This handbook provides basic information about the design, recommended operation, troubleshooting and maintenance

of the drive system and lower works components used on P&H mining shovels. The material presented in these pages
is not a substitute for P&H operating, maintenance or service manuals, but rather it is a complimentary piece to them.

© 2005 Harnischfeger Corporation. All rights reserved. All materials contained herein are protected by the United
States copyright law and may not be reproduced, distributed, transmitted, displayed, published or broadcast without
the prior permission of Harnischfeger Corporation. You may not alter or remove any trademark, copyright or other
notice from copies of the content.
LOWER WORKS
CONTENTS
Section Page
1 Introduction . . . . . . . . . . . . . . 1

2 Propel System . . . . . . . . . . . . 3

3 Crawler System . . . . . . . . . . 11

4 Lower Works Lube and

Air Systems . . . . . . . . . . . . . 31

5 Lower Works Structural

System . . . . . . . . . . . . . . . . . 33

6 Operating Tips to
Minimize Maintenance . . . . 39

Lower Works Maintenance/

Inspection Summary . . . . . . 41

Glossary . . . . . . . . . . . . . . . . . . 43

Index . . . . . . . . . . . . . . . . . . . . . 45
1 - Introduction

Background Scope
This publication provides recommended best prac- The procedures required to achieve peak perfor-
tices for achieving lower works peak performance mance, durability and value from P&H mining
on P&H electric mining shovels. It is intended for shovels vary from model to model. For example,
a general audience, including mine management, starting in the late 1960s, P&H shovels were
purchasing personnel, maintenance technicians, designed with a single DC propel motor and a sin-
shovel operators and instructors, as well as mining gle spur gear transmission mounted on the car-
engineering students and other individuals with an body, with relatively large tumblers mounted close
interest in mining equipment. to the ground on bushings (Figure 1). A final gear
set was mounted on bushings in the crawler
The focus of the material in the following pages is frame. These shovels were referred to as “Propel
what constitutes best practices for P&H drive sys- in the Lower” models to differentiate them from
tems and lower works components and why they previous designs using propel transmissions in the
are recommended, not how to perform those prac- upper and using bevel gears to bring power to the
tices. lower. These “Propel in the Lower” machines

Low Drive System High Drive System

Figure 1 The low drive system (left), was replaced with the more efficient high drive system (right)
beginning with the P&H XPA and XPB shovel models in the mid 1980s.

Page 1
 PEAK PERFORMANCE PRACTICES – LOWER WORKS

were later referred to as

“Low Drive” to differen-
tiate them from the
“High Drive” machines
(Figures 2 and 3).
With the introduction of
P&H XP, XPA and XPB
models came dual motor
drive with two separate
but identical sets of drive
machinery mounted in the
lower, one for each
crawler track. The XPA
and XPB shovels feature a
DC propel motor and a
planetary transmission
with a smaller tumbler
mounted higher off the Figure 2 A P&H shovel equipped with a low drive system.
ground. These shovels are
referred to as “High
Drive” models (Figure 3).
Due to the differences
between low drive and
high drive machines, and
other model-specific
design differences,
detailed descriptions of
procedures for various
models are beyond the
scope of this publication.
Still, general principles
apply to all models, and it
is these principles that are
at the heart of this publi-
cation. Please refer to the
appropriate operating, ser-
vice and maintenance
manuals for instructions
for specific models.
Figure 3 A P&H shovel equipped with a high drive system.
In addition to serving as a
general guide to peak per-
formance practices, this publication also provides
information about various upgrades available to
maximize the performance, service life and value
of various models.

Page 2
2 - Propel System

Overview Side Frame Carbody

The propel system
includes propel motors,
blower motors, propel
transmissions, drive shafts,
brakes and drive tumblers
(Figure 4). The propel
motors, blower motors and
brakes are mounted on the
propel motor base, which
is mounted on the shovel’s Propel
Propel
carbody. The transmis- Motor
sions, drive shafts, and Motors
Base
tumblers, as well as the
crawler track assemblies,
are mounted on the side Blower
frames. While the tumblers Motors Brake
are part of the propel sys-
tem, they are also integral Crawler
Propel Track
to the crawler system and
Transmission Assembly
are therefore covered in
Section 3. Figure 4 Dual propel, planetary high drive system components.
The propel system is used
to position the shovel to
optimize digging geometry with the bank, to repo- Single Propel vs. Dual Propel
sition the shovel as it digs in the bank, and to relo- As explained in Section 1, P&H introduced spur
cate the shovel in the mine. gear, low drive, dual propel to P&H shovels in the
early 1980s. The XPA and XPB models intro-
Depending on the individual mine, a shovel’s pro-
duced the dual propel, planetary high drive in the
pel systems is active approximately 4% to 7% of
mid 1980s. Previous models used a single motor
the time the shovel is operating. The hoist, crowd
to drive both crawler tracks. The single-motor,
and swing motors are far more active but the track
spur gear drive design required high-maintenance
system experiences higher loading. As a result, the
operational jaw clutches between the transmission
propel motors and transmissions are nearly as vul-
and final drives mounted in the crawlers, as well
nerable to abuse and/or premature fatigue prob-
as high-maintenance open V-brakes.
lems but require somewhat less maintenance than
their hoist, crowd and swing counterparts. With a dedicated motor and transmission for each
crawler track, dual propel provides significant

Page 3
 PEAK PERFORMANCE PRACTICES – LOWER WORKS

benefits. Dual propel enables differential steer- with the tumblers, all the propel machinery is
ing, which means if the operator is propelling mounted higher than its low drive counterparts,
and there is room, the operator should turn at a elevating the machinery further from the dangers
larger radius to reduce wear (Figure 5). of damage and/or contamination from the pit
floor.

Propel Motor and Blower

“Differential speed” Description
steering
Each dual propel drive system consists of a fast-
response, reversible, direct current (DC) propel
motor, which is direct-coupled to a propel trans-
mission. Heavy propel loads and tight turning
radii generate large amounts of heat in the motors,
which can cause thermal damage to insulation
materials. Each propel motor therefore incorpo-
Clutch-brake rates an externally mounted forced-air blower to
“skid” steering ventilate and cool the motor (Figure 6).

Propel
Motor
Figure 5 Differential steering provides
the opportunity to turn at a larger
radius when a tight radius is not
required. With lock and steer there is
no choice.

Planetary dual propel substantially sim- External

plified the linkage from the motor to Blower
the final drives by eliminating:
• Clutches
Planetary Transmission
• Bushing-mounted drive shafts and
horizontal shafts Figure 6 Each propel motor, with an external
• Exposed brakes blower, is direct-coupled to the planetary propel
transmission.
The planetary dual propel resulted in more effi-
cient power utilization, greater dependability, and
as much as a 50% reduction in maintenance cost Propel motors are designed to provide speed and
of low drive shovels. torque to produce the tractive effort required to
move the shovel forward and back, and to steer.
With dual propel, each track’s speed and Design criteria considered for a propel motor of a
forward/reverse direction can be controlled inde- particular shovel model are the tractive effort
pendently, allowing more efficient turning with required for the application, and proficient grade-
differential steering, and counter rotation of the ability of a typical mine. An example of tractive
shovel. Furthermore, on planetary lowers, along effort and shovel speed at various grades is shown

Page 4
 2 – Propel System

in Figure 7. For more information on P&H All ENCORE motors are completely rebuilt to
motors, please refer to the Peak Performance original equipment specifications, incorporating
Practices for Electric Mining Shovel DC Motors the latest design improvements.
(XS-2321) publication.
All motors and transmissions
are disassembled, steam
cleaned and thoroughly
inspected, with micrometer
verification of tolerances, and
tested for mechanical and
electrical performance
(Figure 8).

Tractive Effort, K#
Speed (MPH)

In addition to providing OEM

performance and reliability at
a fraction of the cost of a new
component, each ENCORE
replacement comes with the
same full warranty as a brand
new unit. Your MinePro
Services representative will be
glad to provide full details of
the ENCORE program.
-10 0 10 20 30 40 50

% Grade

Speed Effort

Figure 7 As the grade increases, the tractive

effort required to propel the shovel increases.

Motor Repair, Rebuild, and

Exchange
As the only mining equipment manufacturer
that designs and builds its own heavy-duty
mining motors, P&H enjoys a unique place
in the industry. In addition to supplying its
own hoist, crowd, swing, and propel motors,
P&H MinePro Services maintains motor
repair and rebuild centers with fully quali-
fied technicians providing expert service.
MinePro also offers the ENCORE remanu-
factured component exchange program, Figure 8 An ENCORE armature is re-worked to
which includes motors and transmissions. original equipment specifications.

Page 5
 PEAK PERFORMANCE PRACTICES – LOWER WORKS

Propel Transmission 3) Inspect the oil seals for leaks

4) Check the oil level
General
5) Conduct regular oil changes with correct ISO
The propel transmission transfers power from the
grade oil
shovel’s propel motor to the drive tumblers via the
crawler drive shaft. Prior to the introduction of 6) Clean the air breather
XPA and XPB models, P&H shovels incorporated
With proper care, P&H transmissions will
spur gear propel transmissions and final drives
provide thousands of hours of reliable, trouble-
(Figure 9). All models since those introductions
free performance.
incorporate planetary gear transmissions.
The planetary transmission simplifies the linkage Transmission Repair, Rebuild, and
between the transmission, drive shaft and tum- Exchange
blers, significantly reducing component wear and Strict adherence to procedures is necessary to
maintenance, improving the efficiency of power assure proper transmission performance. P&H
delivery to the tracks. Moreover, the single-mod- strongly recommends that propel transmissions be
ule, sealed transmission prevents contaminants sent to a P&H MinePro Services motor and trans-
from entering the gearbox, further reducing main- mission repair and rebuild center where a factory
tenance requirements. The compact size of the specification overhaul is available (Figure 10).
planetary transmission also simplifies placement Contact your P&H MinePro Services representa-
in the lower works. tive for assistance.
The keys to maintaining peak transmission perfor- When replacing a transmission, never reuse the
mance are to: existing mounting bolts. Always replace bolts with
new ones of the proper geometry and grade, and
1) Ensure that each transmission is properly bolt-
torque them to the specifications provided in the
ed to the crawler frame
mechanical maintenance manual. Since bolts may
2) Check for a properly greased motor coupling loosen, it is very important to re-torque these bolts

Motors Motors

Spur
Gear
Transmissions
Planetary
Spur Gear Transmissions
Set in Crawler Frame
Spur Gear Drive System Planetary Drive System
Figure 9 The efficiency of the planetary drive system (right) is superior to the spur gear drive system
(left) due in part to the direct-coupled power flow from the motor to the output shaft to the drive tumbler
in each crawler frame. The inherent design of the planetary transmission reduces peak tooth loads by
20%, further enhancing performance and longevity of components.

Page 6
 2 – Propel System

If cracking is found in the root of the spline at the

transmission end or the tumbler end of the shaft,
the splines should be monitored more frequently
and more closely (Figure 12). If the cracking
extends beyond the spline and into the shaft itself,
the shaft must be replaced immediately. Once
cracks extend beyond the splines, they will
abruptly angle towards an adjacent crack (“Crows
Feet”), and intersect. At the point where the
cracks intersect, a shaft could shatter under load
and cause severe damage to the transmission or
the tumbler. Shafts often fracture in a star pattern
that applies axial pressure on the transmission
Figure 10 P&H MinePro Services provides com-
when fracture occurs.
pletely remanufactured transmissions, with the
same strong warranty as new equipment, at a
fraction of the cost of new.

a week after installation to the specifications pro-

vided in the mechanical maintenance manual.
To transmit torque from the motor to the transmis-
sion, a motor coupling is used. Proper alignment
between the motor and transmission is essential.
Misalignment can cause the coupling or a bearing
to quickly fail and possibly damage the motor or
transmission bearings.
Figure 11 Inspecting drive shaft splines for
cracking.
Crawler Drive Shafts
Description
The crawler drive shafts drive the shovel’s tum-
blers. Each drive shaft is splined to its respective
transmission and track drive tumbler, and is sup-
ported by bearings at each end.

Drive Shaft Inspection

Crawler drive shafts should be inspected periodi-
cally as specified in the maintenance manual for
proper lubrication, excessively worn or damaged
components, shaft cracking, loose or missing bolts Figure 12 If cracking is not immediately visible,
and capscrews, and for proper engagement mag particle or dye penetrant testing may be
between the drive tumbler and crawler belt required. Minor cracking as shown above does
(Figure 11). not necessitate shaft removal, but requires period-
ic monitoring.

Page 7
 PEAK PERFORMANCE PRACTICES – LOWER WORKS

Drive Shaft Upgrades (Figure 14). Both types are spring-set and air-
Beyond the design differences between spur gear released.
and planetary transmissions, propel transmissions When the brakes are released, air pressure
use essentially the same planetary gearboxes. The piped through a solenoid-controlled directional
primary difference between gearboxes is with the control valve keeps the springs compressed and
drive shafts. To handle the greater torque demands allows the propel motors to turn. If electric
of P&H’s largest shovels; the 4100TS, power is lost, or if air pressure is lost, the con-
4100BOSS, and 4100XPB, a larger output spline
trol valve will close, causing air pressure to be
and a larger diameter drive shaft were developed.
removed from the brake. The springs will
To match the performance of P&H’s largest expand and exert pressure to the brake linings,
machines, drive shaft upgrades were made avail- preventing free movement of the propel motor.
able for the 4100, 4100A and 2800XPB shovel
models. While the upgrade will not enhance actual
propelling performance, mines appreciate
the longer life, and reduced maintenance
requirements associated with these more
robust drive shafts. For inventory and
rebuild planning, customers are now able
to enjoy the interchangeability of trans-
missions between various machines,
enhancing mine economies of scale.

Propel Brakes
Description
A parking brake is mounted on Male Brake Arm
each propel motor shaft to prevent Clutch
Member Male
the shovel from moving
Female Clutch Female Clutch Clutch
when it is digging or after Member
it has been shut down. Member Member
These brakes are holding
brakes only, and are not
used to stop the shovel
when it is propelling
Final Drive Final Drive
(dynamic braking is
Pinion Shaft Pinion
achieved electrically). Propel Shaft
Transmission Brake
Output Shaft Propel Brake
Propel brakes are of two Wheel
Transmission Wheel
types depending on the Brake arm Output Shaft
Brake Arm
shovel model. Earlier mod-
els use a V-brake system (Jaw Clutch Engaged (Jaw Clutch Disengaged
(Figure 13), while later for Propel) for Skid Steering)
models use disc brakes Figure 13 A V-brake type propel brake was used on earlier P&H shovels.

Page 8
 2 – Propel System

Brakes are released by air pressure. If there is tem to ensure that both brakes will set when the
not enough pressure in the shovel’s air receiver brakes are set. This line interconnects exhaust
tank, the shovel will not be able to start until valves, so that even if one exhaust valve fails,
the air compressor produces sufficient air pres- the air from both brakes will exhaust through
sure to cause the brakes to release. When the the remaining good valve. Another solenoid-
operator presses the brake release button, a controlled directional control valve is installed
solenoid valve allows air from the air receiver in the redundant air line that works in conjunc-
to enter the brake. The air pressure causes the tion with electronic controls in the propel brake
springs to be compressed, and the propel maintenance box to permit the release of one
motor is free to rotate. brake at a time during maintenance procedures.

To assure proper operation, air pressure must be Propel Brake Maintenance

regulated to the proper level. Too little pressure
could cause the brake to drag, overheat and fail;
As the brake friction pads wear, the dis-
too much pressure can damage brake compo- tance the piston travels between the set
nents. position and the release position increases.
The amount of piston travel should be mea-
A redundant air line has been added to the sys- sured during maintenance activities. Each

Brake Housing
Split Shims

Brake Hub Outer O-ring

Brake Rotors Dust Seal

Wear Ring
Brake Springs

Brake Piston
Center Plate

Brake Cylinder
Pressure Plate
Inner Piston Ring

Figure 14 Disc type propel brakes are offered as an upgrade on 2300XP and 2800XP machines and are
standard equipment on all later machines.

Page 9
 PEAK PERFORMANCE PRACTICES – LOWER WORKS

brake has its own dimension criteria.

Obtain measurement criteria from P&H The only maintenance recommended by
MinePro Services. P&H Mining Equipment is the replace-
ment of O-rings and the replacement of
During inspections, determine whether the complete brake discs. Brakes should be
air seal around the piston is leaking. Dark returned to P&H MinePro Services for
streaks on the brake housing, roughly per- complete rebuild when necessary. When the
pendicular to the edge of the piston, indi- brake is rebuilt, it will receive new springs,
cate a leaking piston seal (O-ring), as does as well as new rotors with new friction
excessive heat or noise during operation. pads. Other components (wear plate, center
Replace leaking O-rings (each piston has an plate, pressure plate, piston, mounting
outer O-ring and an inner O-ring). studs, etc.) will be replaced with new com-
ponents as necessary.
Excessive heat or noise during operation
could also result from warped discs or dam- P&H Disc Brake Upgrade
aged/missing friction pads.

Transmission
Input Shaft

Disc Brake
Upgrade

Figure 15 P&H disc brakes provide greater reliability and perfor-

mance than earlier V-brakes and easy installation simplifies upgrades.

Page 10
3 - Crawler System

Overview Shoes, Tumblers, and Pitch

The crawler system consists of a crawler track Description
assembly made up of crawler shoes pinned togeth- The propulsion of an electric mining shovel
er forming a movable track upon which the shovel depends upon the smooth interaction of its crawler
rides, front and rear idlers, lower rollers, and shoes and drive tumblers. The crawler shoes are
guide rails. The crawler system is responsible for pinned to each other in a continuous belt forming
carrying and evenly distributing the weight of the a track on which the shovel travels (Figure 16).
entire machine. While the tumblers are part of the
propel system (Section 2), they are covered in this Each belt is wrapped around a drive tumbler at the
section as they are integral to the operation of the rear of the machine and an idler wheel at the
crawler system. front. As the tumbler turns, its drive lugs mesh

Crawler Belt
Front
Idler
Guide Rails
Belt Adjustment
Shims

Shoe Lugs
Lower Rollers
Drive Tumbler
Front
Lower Roller
Tumbler Drive Lugs Rear Idler

Figure 16 Shoe lugs must mesh with the tumbler’s drive lugs to propel the shovel forward or reverse.

Page 11
 PEAK PERFORMANCE PRACTICES – LOWER WORKS

with the shoe lugs, driving the track and pro- Measuring Shoe Pitch
pelling the shovel forward or back. The recommended method of measuring shoe
In order for the tumbler and shoes to engage prop- pitch is to measure the pitch of a section of six
erly, the spacing between the shoe lugs and tum- crawler shoes while under tension after forward
bler drive lugs must match. This spacing is called propel (Figure 17). The section of track must be
“pitch.” A crawler shoe’s pitch is the linear dis- flat on the ground from end to end to ensure that
tance measured from the centerline of one link (or any slack is taken up. Measure from the center of
shoe) pin to the centerline of the next link or shoe one link pin to the center of the sixth pin, and
pin when the belt is straight and under tension divide by six. This will provide a more reliable
(Figure 17). dimension than measuring the pitch of a single
shoe or smaller section of shoes. Measurement
may also be made from the edge of one pin to the
same corresponding edge on the sixth pin.

Dynamic Track Tension

Inspection
Even after taking a static pitch mea-
surement, experience dictates that a
dynamic pitch inspection is necessary.
Pitch for Six Shoes Mine and field service personnel should monitor
pitch by observing the engagement and disengage-
Figure 17 Shoe pitch is determined by measur- ment of the shoe lugs with the drive tumbler and
ing the pitch of a section of six shoes, from the the manner in which the belt wraps around the
center of one link pin to the center of the link drive tumbler (Figure 18).
pin at the opposite end of the section, and
dividing by six. Tension Loose
Readjust
Proper
Tension

Tension Unacceptable
Damage to Components

Figure 18 Shoe tumbler engagement.

Page 12
 3 – Crawler System

Tumbler Pitch Range tem (incorporated on newer, heavier machines)

Just as crawler shoes have pitch, the drive tum- (Figure 19). The lug style ADS (Advanced Drive
blers have a pitch range. This range is a function System) tumbler and sprocket style DELTA
of the tumbler’s geometry and the radial distance (Deep Engaging Long-Life Track Assembly) tum-
on the tumbler where the shoe pins drive. For bler are central to drive system performance.
example, a shoe may have a pitch of 21.3 inches A major feature of both systems is the larger sur-
and the tumbler’s pitch range is 21.2 to 22.2 inch- face engagement area between the tumbler pock-
es. Shoe and tumbler pitch are defined during the ets and shoe lugs over earlier systems. This results
engineering design process. in increased side and bottom contact, and
When the shoes and tumblers are new, the improved shoe-to-tumbler engagement.
matched pitch provides proper engagement with
the leading tumbler lugs driving the shoes. Over Lug Drive
time the track system will wear, causing the pitch Tumbler
to elongate. This elongation can be greater on one
track than the other. Pockets
Pitch elongation can be caused by shoe pin wear
or shoe pin bore wear, and if it increases beyond
the allowable range for the tumbler it will result in
a pitch mismatch. Pitch mismatch causes the shoe
lugs to interfere with the tumbler lugs, thus accel-
erating wear on both parts as they fight each other Lugs
to occupy the same space. This is evidenced by
visually observing and hearing the rough engage-
ment between shoes and tumblers.
Identifying and correcting for pitch mismatch is
essential for proper shoe and tumbler performance
and long service life.
Sprocket Drive
Over-Pitch Tumblers Tumbler
Over-pitch tumblers are designed with larger
pockets between the drive lugs, and a larger
operating radius in the lug area to allow shoes
with elongated pitch to mesh with the tumbler.
This is a good solution for a mismatch between Pockets
shoes and standard tumblers, provided the shoes
have significant life left.

Drive Systems Sprockets

Description
Figure 19 The larger surface areas between the
Today’s P&H shovels use two types of drive sys-
tumbler pockets and shoe lugs provide increased
tems: either a lug drive system (common with ear-
side and bottom contact for improved shoe-to-
lier, smaller machines), or a sprocket driven sys-
tumbler engagement.

Page 13
 PEAK PERFORMANCE PRACTICES – LOWER WORKS

Both of these systems were designed to provide shoe pins and lugs, thus significantly reducing
superior performance and longer component service maintenance requirements and the likelihood of
life compared to their predecessors, the lug-style premature failure.
“24J” Series and “R” Series shoes.
Drive System Availability
ADS System 24J and R ADS DELTA
The lug-style ADS system represents a complete Model Series Series Series
re-engineering of earlier lug drive system com- Lug Lug Sprocket
ponents, including the drive tumblers, shoes, Drive Drive Drive
link pins and pin lugs. With some 300 lbs. more 1900, 1900AL •
material than its predecessors, the more robust
2100, 2100XP,
ADS shoe design combines 30% lower peak 2100XPA, 2100BLE III •
stresses and a 77% improvement in male lug
2300MKI, 2300MKII,
fatigue life. All the improvements add up to
2300XP •
greater strength and longer component life with
2300XPA, 2300XPB • • •
reduced maintenance and lower operating cost.
2800MKI, 2800MKII
2800XP •
DELTA System
2800XPA, 2800XPB • •
The DELTA system incorporates sprocket-style
tumbler lugs that engage deeply into the shoe, 4100, 4100A • •
driving near the pitch line, and substantially 4100TS, 4100XPB
4100BOSS •
reducing pitch mismatch. By driving nearly at
the pitch radius of the pins, there is virtually no 5700 •
sliding between the tumbler and shoe lugs when
Figure 20 Available crawler drive systems for P&H
engaged, significantly reducing wear.
shovels.
The DELTA system’s tumbler is
also designed with a wide pitch
range, eliminating the need for use
of “over-pitch” tumblers.
Originally developed for the
extreme load demands of the
4100TS, the DELTA system is
available as an upgrade for other
P&H models (Figures 20 and 21).
The pressure angle of the DELTA
drive system is much lower than
other designs due to the inherent
nature of a sprocket, resulting in
little need for high overall track
tension. The lower pressure angle
requires virtually no radial force to
keep the shoes in proper
engagement. The ability to operate Figure 21 The P&H DELTA drive system can be retrofitted onto
with lower track tension allows several shovel models for longer service life and lower operating
substantially reduced loads on costs.

Page 14
 3 – Crawler System

Crawler Shoes environments where floatation is paramount to

proper machine operation (oil sands, coal, marshy
General areas, etc.). Distributing a machine’s weight over
The importance of design and engineering princi- too narrow a belt of shoes may cause excessive
ples, and manufacturing techniques involved in sinking, while too wide a shoe on a hard pit floor
crawler shoe development and production cannot could result in isolated incidents of point loading.
be overemphasized. This is where “the rubber Either condition will lead to premature failure of
meets the road,” so to speak. various drive system components, and unneces-
sary repairs.
Crawler shoes must support the entire weight of
the shovel while responding to forward/reverse
motion and direction changes. They must also be
Shoe Construction
able to withstand abrasive ground conditions, All P&H shoes feature hollow-core construction
rocky and uneven terrain. The shovel’s front shoes to provide an efficient strength-to-weight ratio,
are further subjected to potential dipper strikes and even distribution of loads throughout the
while the shovel is digging, and to the machine’s shoe. Box section construction also helps prevent
harsh tipping motion, which concentrates most of the ends of the shoe from curling up when used on
the shovel’s weight on the front shoes. irregular hard surfaces or from dipper strikes. The
ends of the shoes are also slightly beveled to ease
Similarly, the individual components linking the steering and reduce peak bending stresses.
shoes together must endure extreme turning, twist-
ing, compression and deformation forces while The shoe’s male and female link pin lugs allow
resisting cracking, bending and fracturing under one shoe to be pinned to the next shoe, forming a
stress. The crawler belt must also resist stretching crawler belt (Figure 22). The shoe’s drive lugs
to maintain proper pitch. mesh with the tumbler’s lugs to drive the crawler
belt forward or reverse. The shoe’s roller path pro-
With these considerations in mind, shoe selection vides the surface on which the crawler assembly’s
is an important first step in obtaining long-term lower rollers revolve. Peening grooves are provid-
peak performance from the drive system. ed to absorb metal flow as the manganese shoe
work hardens.
Selecting the Proper Shoe
The two primary criteria for selecting the proper
shoe for a shovel are:
Link Pin Lugs Drive Lugs
1) The shovel’s size, including its weight and the
ground bearing pressure required for the type
of soil on which the shovel will operate.
2) The shoe style, based on the shovel’s
drive system, either the traditional lug
drive or the more recent sprocket
drive.
Soil conditions and desired ground bear-
ing pressure determine the size of shoe
that should be used. Narrow shoes typical- Peening
ly should be used on harder ground, as in Roller Path Grooves
hard rock mining (copper, iron ore, gold, etc.).
Wider shoes are better suited for softer ground Figure 22 Crawler shoe showing key elements.

Page 15
 PEAK PERFORMANCE PRACTICES – LOWER WORKS

Virtually all P&H electric shovels, regardless of gation. Lubrication with open gear lube at the
the machine type, employ extensive use of cast time of installation assists pin rotation, which in
manganese shoes. The exception is the 138-inch turn aids in the process of work hardening the pin
shoe designed for the 4100TS and 4100BOSS bores, thereby enhancing pin life (Figure 24). The
models, which is of cast alloy steel. lube used in the “break-in” period will have a ben-
eficial effect on pin and shoe life long after the
A heat-treated manganese shoe will work harden lube is gone.
to more than twice its original
surface hardness in the roller
path, drive lugs, pin bores, and
ground contacting surface areas.
Typically, new manganese shoes
Pin Keeper
have a surface hardness of 180 Pin Bore
Assembly
BHN (Brinnell), work hardening
to 350–500+ BHN during the
first 3,000 hours of operation.
Manganese shoes characteristi-
cally provide very high impact
resistance and wear resistance.
The 138-inch shoes used on
P&H 4100TS and 4100BOSS
shovels, designed specifically Link Pin
for mining in Canada’s oil sands
region, are substantially wider
than the shoes used in more tra-
ditional mining applications Figure 23 Link pin assembly.
such as copper, coal or iron.
These extra-wide shoes are necessary to distribute
the shovels’ weight and prevent them from sinking
into the soft ground. Due to the weight efficiency
of alloy steel, the 138-inch shoes are of cast alloy
steel.

Link Pins
Description
Link pins provide a solid connection between two
crawler shoes (Figure 23). Link pin wear and
breakage are among the most common problems
associated with crawler shoe maintenance.
Selecting the proper pin and providing pin lubri-
cation at the time of installation are key to long-
lasting pin performance.
The rotating action of the pins reduces loading in Figure 24 Lubing pins during installation.
shoe lugs and limits shoe breakage and pitch elon-

Page 16
 3 – Crawler System

Induction Hardened and Thru associated stress and limit the life of these pins are
Hardened Link Pin Comparison as follows:
Two types of link pins are used on P&H shovels: 1) Adhesive wear occurs when the pin and shoe
induction hardened and thru hardened. P&H pin bore cold weld together and then break
strongly recommends using induction hardened apart while rotating under very high loads,
pins wherever possible due to their superior sur- leaving the pin surface pitted, and the area
face strength and wear durability (Figure 25). The between the pin surface and pin bore contami-
case hardening process associated with induction nated with loose metallic particles. Under high
hardened pins offers 27% greater surface hardness sliding pressure, sufficient heat can be generat-
than thru hardened pins, resulting in substantially ed to locally affect the heat treatment and
reduced wear and breakage. Breakage, however, is microstructure of the pin. This is partly why
not limited by the superior surface hardness of the pre-lubing the pins is so important.
induction hardened pin, but rather by the pin’s
tough, ductile core. 2) Abrasive wear occurs when contaminants
(grains of dirt, sand, etc.) come between the
While thru hardened pin diameters range from pin and shoe pin bore.
3.25" to 5.0", their usage should be limited to
smaller machines and early low drive shovels. On These two wear conditions promote uneven wear
larger shovels, the surface hardness of these pins in the shoe lug and on the pin, creating even more
cannot withstand the stresses induced by the track stress due to point loading. Eventually, the pin
system. Two types of wear that exacerbate the could be prevented from rotating, resulting in pin
or lug fracture.
Induction hardened pin diameters
ranging from 4.0" to 5.0" are used
exclusively on all ADS and
DELTA systems. These pins are
also in wide scale use with most
P&H high drive shovels. These
larger diameter pins are induction
hardened for a higher surface
hardness and increased bending
strength. The tough ductile core of
this pin provides greater resistance
to breakage than smaller diameter,
thru hardened pins.
For P&H 2800 Series shovels, the
4.5" diameter pins used on the
“R” Series and DELTA drive sys-
tems provide a 75% increase in
bending strength over the 3.75"
pins used on earlier systems. And
for the 4100 Series, the ADS and
DELTA systems’ 5" pins provide
95% greater bending strength than
Figure 25 P&H induction hardens pins to provide superior their earlier 4" counterparts
surface strength and wear durability. (Figure 25).

Page 17
 PEAK PERFORMANCE PRACTICES – LOWER WORKS

P&H strongly recommends using induction hard- tion and cracking. Should cumulative wear exceed
ened pins whenever possible because they: 3/8" on each shoe pin as shown in Figure 27, the
• Provide greater toughness mine may consider replacing all pins to remedy a
pitch mismatch situation.
• Provide greater surface hardness
• Reduce pin and lug wear A C A
• Reduce risk of crank-shafting
• Help maintain a straight shoe bore
• Help reduce pitch elongation
• Typically last the life of the shoe
Signs of a Worn Link Pin
The life of a link pin is greatly enhanced if it is D B D
able to rotate within the lugs of a crawler shoe. Cumulative wear = A + B or C + D
The best indicator of a rotating pin is the ring left
at the base of the link pin caused by the retaining Figure 27 Typical rotating pin wear pattern (good
nut rubbing against the pin’s surface (Figure 26). pin lubrication).
A non-rotating pin will not exhibit this ring, and
A A
will wear faster than a rotating pin.

Pin Rotation Ring

Figure 28 Typical non-rotating pin wear pattern

Pin Keeper Assembly (poor or no pin lubrication).

Figure 26 Pin rotation ring and keeper assembly. Replacing Worn and Broken Link Pins
Both thru hardened and induction hardened pins
The wear pattern typical of a rotating pin is shown should be replaced immediately when fracture
in Figure 27. A pin properly lubricated at the time occurs or soon after the shoe pitch falls outside of
of installation exhibits signs of wear in the center specifications. Running with a broken pin also
of the pin and toward its outer edges on opposite effects the load on all neighboring shoes and pins.
sides of the pin in a symmetrical pattern. Pins not Failure to replace a broken pin can cause the shoe
lubricated at the time of installation display a non- pin bores to be severely damaged or cause the
symmetrical wear pattern, referred to as “crank- shoe lugs to break. Fracturing of a second bore is
shafting” (Figure 28). Other signs of wear include often the result of a prying action subsequent to
out-of-round pins and other types of pin deforma- the first break.

Page 18
 3 – Crawler System

Examine the pins and pin bores to help determine

the cause of pitch elongation. If pin replacement
does not bring pitch into tolerance, an over-pitch
tumbler may be required to take up the slack.
Pin keeper assemblies prevent pins from working
their way out of the pin bores. When replacing
pins, inspect the pin keeper nuts and bolts and
replace them as needed (Figure 26).

Assembling New
Figure 29 Installation of the crawler shoes with
Crawler Shoes the male shoe lugs facing downward as they hang
General off the front idler. Shoes can be installed with
A new crawler shoe belt should never be installed male or female lugs facing downward.
with a worn drive tumbler or worn crawler rollers
and idlers. Doing so will cause premature wear of The life of a belt that has sustained shoe damage
the new belt. Remember, manganese shoes go due to numerous dipper strikes may however, be
through a work hardening process, and the wear extended by turning the belt from end to end. This
pattern in the roller path and drive lugs will follow will expose the inboard side of the belt to the out-
the contours of the associated components. board side of the shovel and vice versa.

When assembling the crawler shoes, it is impor- Turning the belt end for end may also extend the
tant to lubricate the link pins with a high solids belt’s life if the lug wear on the shoes is greater in
lubricant such as an open gear compound. When one direction. The drive tumblers should also be
the machine is first propelled, the lubrication will turned end for end at the same time, as the worn
assist initial pin rotation, which will facilitate the side of the tumbler lugs would accelerate wear on
work hardening process of the pin bores. If the the shoes.
pins and bores are not properly lubricated they
may suffer adhesive and premature abrasive wear
that could ultimately inhibit the life of the track
system.
Maintaining Correct
Track Tension
Direction of Shoes for Assembly General
Traditionally, the recommended direction of Track tension that is set too tight or too loose
crawler shoes was with the male lugs facing down results in excessive loading of the crawler shoe
as they hang over the front idler (Figure 29). With pins and pin lugs. Moderate to loose tension is
today’s heavier shovels and the limited use of ideal. It is better to adjust the tracks more often to
cleated shoes, directionality is no longer an issue loose tension than to do so less frequently to tight
with the sprocket drive. The direction of the tension. Ideal track tension settings are shown in
shoes; however, will need to be consistent on both Figure 30.
sides of the same machine. For lug drive shoes,
install with male lugs down. This will provide the Loose tension reduces pin and pin lug loading
best shoe-tumbler engagement in forward propel. when operating on uneven ground. A set of shims
on the front idler assemblies allows adjustment of

Page 19
 PEAK PERFORMANCE PRACTICES – LOWER WORKS

Lug Drive Sprocket Drive

Torque

Torque

Sprocket
Teeth
Exiting Lug Proper Amount of Sag Here
Partially Disengaged from Tumbler

Track dynamically observed with torque in reverse Track observed with stationary track after
propel direction reverse propel
Figure 30 Ideal track tension for lug and sprocket drive systems.

track tension. The DELTA (sprocket) system has a Effects of Tight Track Tension
real advantage here, in that it is very tolerant of With too little slack under dynamic loading during
loose track belt tension without causing a poor propel, very high peak track loads can be experi-
mesh situation. Too loose tracks, regardless of the enced (Figure 32). If left this way, severe damage
drive system, will bind behind the front idler and to pins and pin lugs can result. Over-tensioning
front of the tumbler, creating additional stress to the tracks can cause binding between the shoe
the track system. drive lugs and tumbler lugs. Tight track tension
The front idler rollers are used to
Abutment
maintain track tension.
Adjustments are made with
hydraulic jacks placed between
the journals and abutments on Journal
each side of the crawler frame
(Figure 31). Self-storing shim
plates are inserted between the
journals and frame to maintain
belt tension after the jacks are
removed. It is important to con-
sult the service manual to know
how much force is to be exerted
with the hydraulic jacks to avoid Hydraulic
over-tightening the track system. Jack

Figure 31 Removal and insertion of shims on the front idler

assembly provide for track tension to be loosened or tightened as
needed. Moderate to loose tension is ideal.
Page 20
 3 – Crawler System

Lug Drive Sprocket Drive

Torque
Torque

Sprocket
Teeth

No Gap on Exiting Tumbler No Sag or Slack in the System

Dynamic observation Static observation, after a reverse propel
Figure 32 Tight track tension on lug and sprocket drive systems.

has been found to be a very strong contributor to improper meshing between the shoes and tumblers
overloading shoes and to link pin and/or shoe fail- (Figure 33). In extreme cases, the shoes can
ure, particularly on uneven ground. become fully disengaged from the tumbler. The
result of improper meshing will be accelerated
Effects of Loose Track Tension wear to the shoe and tumbler drive lugs.
Depending on the type of track system (lug or
Unlike tight track tension, loose tension has a few
sprocket) if track tension is too loose the shoes
favorable characteristics as well as unfavorable
can move outward on the tumbler resulting in
ones. A relatively loose track reduces nominal

Lug Drive Sprocket Drive

Torque

Torque

Sprocket
Teeth
Large Gap on Exiting Shoe Large Sag
Dynamic observation Static observation, after a reverse propel
Figure 33 Loose track tension on lug and sprocket drive systems.

Page 21
 PEAK PERFORMANCE PRACTICES – LOWER WORKS

shoe loading and allows the shoes to conform to Keys to Prolonging Shoe and Pin Life
the ground better. Loose track tension is also criti-
Figure 34 lists key practices that will prolong shoe
cal to reducing propel loading.
and pin life on P&H shovels.
When track tension is excessively loose, however,
it can cause pitch interference. Smooth entry/exit
of shoes will not be possible and the shoes and Keys to Prolonging
pins will experience increased loading as they exit Shoe and Pin Life
the tumbler pocket. This can accelerate tumbler
wear and shoes may actually skip over the drive z Use induction hardened pins.
tumbler lugs. Too loose tracks will also bind
behind the front idler and front of the tumbler, and z Lubricate pins at the time of
depending on machine movement, may rub installation.
against the side frame structure. z Trim toenails, side flow, and pin eye
metal flow before interference
Pulling Shoes After Initial Wear-in occurs.
As a new crawler belt is broken in, the belt z Replace broken pins promptly.
stretches, causing the belt tension to loosen. Often
the tension will loosen enough that one shoe may z Maintain proper track tension and
be removed from the belt to restore prop- pitch.
er tension. These shoes may be set aside z Replace worn tumblers.
for future replacements.
z Do not use new shoes with used
rollers or tumblers.
Insertion of New or Worn Shoes in a
Worn Belt z Maintain a smooth pit floor.
When inserting one or more new shoes in a worn
belt, the roller paths of the worn shoes will be
Figure 34 Prolonging shoe and pin life.
lower than the new shoes to varying degrees
depending on the age of the old shoes. It is, there-
fore, good practice to avoid spacing individual
new shoes across a worn belt of shoes whenever
possible. Try to group new shoes next to each
Identifying and Preventing
other to minimize the up-and-down motion of the Shoe Problems
lower rollers, which concentrates the roller load
on the corner of the roller path.
General
Due to the harsh working conditions encountered
Worn shoes or shoes with high hours may be used in a mining environment, crawler shoes are sus-
as replacements, but the same principle applies. ceptible to cracking, breaking, abrasion, exces-
Whenever possible, group similarly aged shoes sive metal flow and yielding, and other kinds of
together to limit the up-and-down motion of the damage, as well as normal wear and tear. Shoe
lower rollers. Remember, manganese is a dynamic replacements can be costly in terms of labor and
material and worn shoes will grow in length and downtime, but several kinds of problems can be
width. Therefore, for proper alignment it may be prevented by early detection through routine
necessary to remove material from the lugs of new visual inspection, and timely corrective action
and used shoes to fit. (Figure 35).

Page 22
 3 – Crawler System

Metal Flow and Toe Nails ment and premature wear of pins, pin lugs and
As manganese work hardens under the weight of other drive components.
the shovel, a front-to-rear and side-to-side flow of To avoid these problems, toenails should be
manganese in the roller path area ensues (Figure trimmed before they begin to interfere with the
35). The front-to-rear flow of material at the ends smooth operation of the belt, usually within the
of the shoe’s roller path will sometimes extrude to first 3,000 hours of the belt’s operation (Figure
a wedge-shaped geometry known as a “toe nail” 37). This can be done with air arc cutting in the
(Figure 36). Peening grooves are provided to roller path area, followed by grinding the rough
absorb side-to-side and front to rear metal flow. edges smooth. It is also recommended to gouge
Once the peening grooves have filled up, if side- and grind the chamfers around pin bores to elimi-
to-side metal flow continues it can cause back nate cracks due to initial metal flow. Contact your
bending of the crawler shoe. P&H MinePro Services representative for infor-
Toe nailing can become severe enough that the mation concerning the gauges and techniques
flow from the ends of the roller path will interfere required to prevent compromising the metallurgy
with the adjacent shoe. This can create hairline of the crawler shoes.
cracks in the toe nail and put high stresses on the
pins and pin bores, contributing to harsh engage-

Before

After

Figure 35 Metal flow is exhibited in the roller

path of most crawler shoes.

Figure 37 Material that extrudes from the roller

path (before) will need to be trimmed when
excessive (after).

Roller Path Crush

Lower rollers help distribute a shovel’s weight
over the length of the crawler track. Peak digging
Toe Nail moments and uneven floors cause peak loading on
some rollers causing some crushing or compres-
sion of the roller path. This can cause the path of
Figure 36 Toe nails have formed on these crawler the lower rollers to deform slightly, increasing
shoes as a result of metal flow.

Page 23
 PEAK PERFORMANCE PRACTICES – LOWER WORKS

stress on the rollers. DELTA and ADS shoes fea- Lost Pin Keepers
ture enhanced roller path geometry to reduce peak Link pin retention nuts and bolts can work loose
contact stresses and increase resistance to shoe with the stresses and vibration of digging, pro-
crushing. pelling and ground hazards. The best way to mini-
Crushing can be measured with straight edges and mize pin keepers from working loose, is to weld
measuring devices, and the amount of crush is a the nuts to the bolts at the time of installation. To
good indicator of the remaining life of shoes and be effective the nuts are to be tightened to the
tracks. The extent to which shoes exibit crush can bolts as per service manual. Hardware that is
be seen with a “Go” gauge (Figure 38). missing must be replaced immediately or the pins
could work their way out of the pin bores and
cause serious shoe damage. Daily pre-operational
walk-around inspections can identify such defects.

Cracked Shoe Lugs

In severe stages, lug cracking is easy to see but to
catch the problem in its early stages requires clos-
“Go” er scrutiny. Like lost pin keepers, cracking can
Gauge result in pin loss or distortion.

Broken Pins
Figure 38 “Go” gauge is used to verify clearance
When a pin breaks it may appear cocked or dis-
between adjacent crawler shoes.
torted in the pin bore as opposed to being flush.
Unless it is caught early, this can cause the pin
bore to wallow from a circular shape to an oval
Wing Damage shape, preventing the pin from rotating and
Shoe wings are vulnerable to dipper strikes, and increasing stress on both the pin and pin bore
the vulnerability increases with the width of the (Figure 40). Again, use the telltale sign of the ring
shoe. Multiple impacts with a dipper not only left at the base of the link pin caused by the
damages shoes, but will cause side frame and dip- retaining nut rubbing against the pin as it rotates.
per structural cracking (Figure 39). This kind of A non-rotating pin will not exhibit this ring. When
damage is usually not a serious problem and it can one of a shoe’s pins breaks it puts an enormous
be minimized with careful operator technique. load on the remaining pin, which can quickly
cause the second pin or lug to bend and fail.

Broken
Pin

Figure 39 Damaged shoe wings. Figure 40 Broken pin.

Page 24
 3 – Crawler System

Back Bending Pit Floor Maintenance

Back bending is a natural phenomenon that occurs Keeping the pit floor level and even will help
with manganese crawler shoes due to metal flow extend the life of shoes and link pins. An uneven
and is seldom the cause of shoe failure. Excessive floor may cause the shovel to rest on just a few
back bending may result when roller path crush is shoes, creating point loading and unnecessary
great, and the shoe is nearing the end of its useful fatiguing of shoe pin lugs and pins. Propelling
life (Figure 41). over rocks, berms, and ruts on uneven ground can
cause high loading on the link pins and pin lugs,
making them more susceptible to breakage.

Rollers and Idlers

Description
Rollers and idlers are used to support and guide
the crawler belt, while transmitting force and
motion to the belt without changing its speed or
direction.
In addition to the front and rear idler rollers, a
row of lower rollers is located at the bottom of
Figure 41 Back bending can be measured using a
the side frames to distribute the shovel’s weight
straight edge to determine the amount of deflection.
more evenly over the length of the crawler track
(Figure 42).
A common misconception is that back bending
creates a convex shape in the bottom of the shoe,
not a concave shape. One might think that
since the weight of the shovel pushes
down in the middle of the shoe that
the shoe would bow up and take
on a convex shape. This is not the
case.
Under the shovel’s weight, a lot
of metal deformation and deflec-
tion occur in the shoe’s roller
path. As this continues, the defor-
mation extrudes and pushes out
in all directions away from the
center of the roller path, creating
residual compressive stress. This Rear Idler
stress is most constrained in the
longitudinal direction. The com-
bination of high residual stress
and high restraint cause the roller Rollers
path area to lengthen, resulting in
back bending. Figure 42 Crawler roller and rear idler components.

Page 25
 PEAK PERFORMANCE PRACTICES – LOWER WORKS

Each roller is bronze bushed from both sides and Selecting the Proper Rollers
turns on a fixed, hardened steel shaft that is Metal rubbing against metal generates high friction
pinned to the crawler frame (Figure 43). and wear. Bushings and thrust washers are the first
Lubrication is provided via a passage through the line of defense for the rollers and side frames.
center of the shaft. Lubricating grease flows out They are designed to be softer than the rollers to
the roller sides, causing a natural flow of contami- absorb abrasive wear rather than allowing the more
nants away from the bushings. costly rollers and side frames to absorb such wear.
Lower rollers and associated components are very P&H uses numerous alloys to precisely match the
close to the pit floor and therefore are exposed to delicate balance of toughness and softness needed
abrasive material. Seals and purging lubricant help for the bushings and thrust washers to protect
protect sensitive roller components by limiting roller and side frame surfaces and maximize ser-
contamination. The manufacturing process of the vice life.
hardened wear surfaces used in the rollers them-
selves provides additional protection. Generally, Similarly, on the outer surface of the rollers, P&H
the harder the wear surface, the less wear there is 50+ lower rollers provide superior hardness
when exposed to contamination and abrasion. (Rockwell 50-54c) for 20-25% longer life than

Bushings Roller
Crawler Frame View of Front Roller
(right-hand sideframe*)

Hardened
Wear
Plates

Retainer Tube

Retainer Pin
View of all Rollers Other
Thrust Than the Front Roller
V-ring Seal Thrust
Washer (right-hand sideframe*)
Washer
Lubricant
Passage *Lube flats go to the rear on all pins except the Rear Idler Pin.
Rear Idler Pin flats go towards the front of the machine.

Figure 43 Lower roller assembly.

Page 26
 3 – Crawler System

conventional rollers (Figure 44). They are Lubrication of Lower Rollers and Idlers
designed to provide a better hardness match with
Lower roller bushings are pressure lubricated
the work hardened manganese ADS and DELTA
through an axial hole in the pin, traveling through
shoes. They are also matched to specific frames,
the pin and exiting through a radial hole (Figure
however, and may not be suitable for all applica-
43). The lubricant works into the roller’s two
tions (Figure 45). bushings. As the volume fills up, the lubricant is
purged out of the roller. Excluder seals
P&H 50+ Hardening Compared
allow the grease to be expelled while
With Other Processes In The Industry
keeping contaminants from entering.
530 BHN P&H 50+ General Maintenance of Lower
hardened rollers
Rollers and Idlers
As the lower rollers, idlers, pins and
Current thru bushings wear, the entire shovel tends
400 BHN hardened rollers to descend a little closer to the ground.
If the wear becomes significant, lower
350 BHN
Original rollers will show signs of spalling, and
the crawler shoes can begin to wear
thru
into the crawler frames (Figure 46).
hardened
Gauges are available to measure the
rollers
profile of rollers and idlers for wear
and side frame clearance. If the mea-
surements exceed the wear limits speci-
fied, the worn components should be
replaced. The easiest method is to sim-
ply monitor the clearence from the
Crawler
Frame
Figure 44 P&H 50+ rollers (530 BHN) and work
hardened manganese shoes are closely matched, pro-
viding longer life for the shoes as well as the rollers.

Drive
Lugs

Figure 45 P&H 50+ spin hardened rollers pro- Figure 46 These crawler shoe drive lugs are
vide 20-25% longer life than conventional rubbing against the crawler frame due, in part, to
rollers. excessive wear of the roller assembly.

Page 27
 PEAK PERFORMANCE PRACTICES – LOWER WORKS

shoes to the crawler frame. If the shoes drag on inch or more. Gauges are available to measure the
the crawler frame, the shoes and/or rollers need to outside diameter of the roller for wear.
be replaced and are at the end of their useable life.
Sealed Idler Upgrade Kits
Rotating Rollers When a shovel is digging, the front idlers are
Of the eight lower rollers on each track, the ones under very heavy loads. They are also susceptible
that are the most heavily loaded are the two in to external forces such as the entry of contami-
front, where the digging takes place, and the two nants, side stresses during steering, and the impact
in back where the drive tumbler is located. To pro- of dipper strikes. To address these issues, front
vide even wear and extend the service life of the idler upgrades are available for retrofit on the fol-
rollers, the two front rollers and two rear rollers lowing shovels: 2300XPA/XPB, 2800XPA/XPB,
may be exchanged with the four inner rollers. and 4100A/TS (Figure 47).

Inspecting Bushings on Rollers Front Idler Maintenance

and Idlers Removal of the front idler for maintenance is
Roller and idler bushings can be inspected using a accomplished by using the hydraulic jack bracket
suitable pry bar to lift the roller/idler and measur- in conjunction with the track adjusting hydraulic
ing the movement. The bushings and thrust wash- ram on later machines and those equipped with an
ers should be replaced if the movement is 3/16 upgrade (Figure 48).

Locking
Thrust Lube Guard
Washers

Grease Idler Shaft

Passage

Bearing
Blocks Flanged
Bushings

Front Idler “V”-Ring Seal

Figure 47 The P&H front idler upgrade shown above will increase front idler dependability.

Page 28
 3 – Crawler System

Front Idler

Bearing Energized
Block Hydraulic
Ram

Hydraulic Ram

Jack
Bracket

Additional
Shims
Initial Number Free
Frozen of Shims Idler Pin
Idler Pin
Figure 48 By energizing the hydraulic ram and varying the number of shims in the jack bracket, the pin is
broken free from the bearing block.

The jack bracket is easily attached to the bearing pin-on guide rails. Pin-on rails feature high hard-
block using the bearing block mounting hardware. ness for high wear resistance.
Once installed, the hydraulic ram is placed into
the bracket, energized, and shimmed as required Determining when to replace the guide rails or
until the pin is free of the bearing block. structural plates is a matter of visual inspection.
Since the crawler shoes are of cast manganese,
their surfaces are work hardened to a higher hard-
Guide Rails
ness than the plates or rails, which are designed to
Guide rails are replaceable castings or structural
plates that are either pinned or welded to the top
of the crawler frames (Figure 49). Each rail
is contoured to the shape of the
shoe’s roller path, and guides the
track system over the top of the
crawler frame, forward or back,
as the shovel propels.
Earlier shovel models used struc-
tural plates instead of guide rails.
When the plates became worn they
were torched off and replaced. Retrofit
kits are available through P&H Guide Rails
MinePro Services to equip older shov-
els with the replacement simplicity of
Figure 49 Guide rail installation on the crawler frame.

Page 29
 PEAK PERFORMANCE PRACTICES – LOWER WORKS

wear faster than the shoes. Allowing the rails to Crawler System Inspection Table
wear excessively may result in the crawler shoes Figure 50 summarizes the key inspections of the
dragging on the carbody. This situation creates crawler system to ensure peak performance.
loose track tension and pitch mismatch between Please reference the operator’s and mechanical
shoes and tumblers, accelerating shoe wear. maintenance manuals for your machine for com-
Improper track tension can also cause premature plete crawler system inspection procedures.
wear of the guide rails or plates; therefore, it is
important to do routine checks of the track system
to ensure tension is neither too tight nor too loose.

Crawler System Inspection

Periodic inspection of the crawler system z Cracking and missing material at the
includes visual checks for: ends of the roller path (excessive toe
z
nailing)
Drive tumbler/shoe engagement
z Roller path collapse
z Loose or missing crawler shoe pin
keepers z Excessive tension or slack in the
z
crawler belt
Pin rotation
z Condition of tumbler lugs
z Broken pin (pin cocked or distorted in
the pin bore) z Spalling of lower rollers (especially
z
corners of tread)
Pin bore wallowed out
z Color and quantity of grease expelled
z Excessive wear (elongation) of shoe
from tumbler, rollers, and idlers
pin eyes
z Contact between rollers and crawler
z Broken shoes (wings/pin lugs)
frame rails
z Binding between shoes (inspect the
z Worn guide rails (shoe contact with
ends of the roller path for binding
carbody)
between adjacent shoes as viewed as
they wrap around the tumbler) z Excessive side frame wear

Figure 50 Crawler system inspection table.

Page 30
4. - Lower Works Lube and Air Systems

Lube System grease and open gear lubricant to the upper works,
and grease to the lower works.
There are basically two types of automatic lubri-
cation systems in use on P&H shovels to lubricate Two banks of injectors on each side frame deliver
the crawler drive system: 1) a mechanical, time- grease to the front and rear idler rollers, the rear
based system, and 2) a PLC-based system devel- idler bushings, lower rollers, drive shaft bearings,
oped initially for the 4100XPB. The PLC-based and the tumbler bearings and seals (Figure 51).
system is also available as an upgrade for 2800XP Without the proper grease, parts will wear
through 4100A shovels. Both systems provide prematurely.

Rear Injector Bank Front Injector Bank

11 Injectors

11 9 8 7 6 5 4 3 2 1 10

Supply
Lube
Hose
Supply
Injector
Hose

Figure 51 Crawler drive system lube system.

Page 31
 PEAK PERFORMANCE PRACTICES – LOWER WORKS

Keeping the lube system operating at peak perfor- The lower air panel, located in the lower control
mance levels requires inspections with each pre- cabinet, houses an air regulator and three direc-
ventive maintenance cycle. Check for dry or tional valves: one valve for each of the propel
cracked hoses and replace them as needed. All brakes, and one for the optional cable reel (Figure
connections should be secure and free of leaks. 52). Air pressure is set at 105 psi on most P&H
shovels.
Also check the injectors for leaks and to see that
the pins move freely. The injectors can be cycled Routine air system inspections will help assure
manually to verify that the pins are moving. proper brake operation and performance. Check
for cracked hoses and leaky fittings, and for prop-
A stuck pin indicates that the injector has become er solenoid valve operation. Brakes can be manu-
contaminated. The injector may be taken apart and ally released to check the performance of the air
cleaned but many mines find this overly demand- system.
ing. If an injector is not working properly the
entire bank of injectors should be replaced. P&H
MinePro Services is authorized to rebuild defec-
tive injectors. Manual release of the propel brakes can
cause unexpected movement of the shovel
and result in severe injury, death or dam-
Air System age to equipment. Be sure all personnel
and equipment are clear of the area before
A reliable supply of clean, dry air at the proper releasing the propel brakes.
pressure is essential to release the propel brakes,
and for operation of a cable reel if the shovel is so
equipped.

Lower
Control
Cabinet

Air Hose

Propel Brake
Maintenance Box Brake
Solenoid Box

Figure 52 The air system supplies air for each propel brake and for an optional cable reel.

Page 32
5 - Lower Works Structural System

Overview the carbody. The 4100XPB uses hardened dowels

along with the shear ledge and rod bolts to prevent
The lower work’s structural system includes the
separation between the crawler frame and carbody
carbody and crawler frames that are made of high
shear ledges (Figure 54).
strength low alloy steel. Shear ledges run the full
length of the carbody’s sides to distribute the ver- The bolts’ sole purpose is to generate a required
tical load of the shovel’s weight and working level of preload, which in turn produces friction
loads over the entire length of the side frames between the carbody and crawler frames. Friction
rather than at point concentrations (Figure 53). is critical to minimize relative motion between the
Shear Ledge structures.
Machined Mating Surfaces
Shear
Carbody Ledge
Crawler
Frame
Dowel

Figure 53 The weight and working loads of the

machine are transferred to the crawler frames
through each shear ledge.

Crawler Frame Bolting

General Rod Bolts
The crawler frames must be bolted tight to the
carbody along the shear ledge, allowing a certain Figure 54 The carbody and side frames support
degree of freedom and elasticity relative to the the shovel’s weight and working loads. Rod bolts
loads applied without overstressing the structures. connect the side frames to the carbody and resist
side loads from steering. Because of the shear
All models except the 4100XPB use rod bolts ledges, the bolts are not required to carry vertical
with the shear ledge to secure the side frames to loads.

Page 33
 PEAK PERFORMANCE PRACTICES – LOWER WORKS

Relative motion stemming from too little preload To avoid costly side frame and carbody repairs,
friction can cause high peak loads on the shear periodic inspection is recommended to check for
ledge, resulting in deformation and cracking of side frame rod bolt tightness and structural cracks.
one or both structures. Too much bolt torque can If the bolts need to be re-tensioned, they should be
distort the structures, causing structural cracking checked again after a week or two. P&H also rec-
and bolt breakage. For these reasons it is critical ommends an ultrasonic test inspection of all rod
to maintain the recommended bolt torque preload bolts for partial failure on a semi-annual basis.
(Figure 55).
Types of Side Frame Fasteners
Bolt failures on a shovel are rarely due to over-
load. Instead, they fail from too little preload or a There are four different types of side frame fasten-
loose carbody/side frame connection. In either ers, each with its own fastening method and
case, cyclical fatigue from bending and tensile equipment.
loading is the result.

Figure 55 Properly preloaded rod bolts produce needed friction between the carbody
and the crawler frames of the P&H electric shovel. Shown above is the ‘TorqueRite’
clamping system available through MinePro.

Page 34
 5 – Lower Works Structural System

1) The Hydraulic Rod Bolt Tensioner is an 2) SuperNut™ Tension System uses a series of
accurate means to preload bolts, but less accu- jackscrews around the circumference of a
rate than the SuperNut™ or P&H threaded tensioner to stretch studs or bolts
TorqueRite™ methods. With the bolt tension- (Figure 56). Great clamping force can be
ing process, rod bolts are tensioned rather than achieved by using many jackscrews without
torqued, eliminating the need to weld nut-lock- having to use great torque on any single
ing plates or “keepers” inside the carbody to jackscrew. No reaction arm or nut retainers are
prevent the inner nuts from turning. In opera- required, only a torque wrench, breaker bar,
tion, the tensioner is threaded onto a standard and impact socket.
rod bolt. When hydraulic pressure is applied,
the rod bolt is stretched and the rod bolt nut Jackscrews are available in various sizes with
turned down with the tensioner’s T-Bolt han- varying numbers around the circumference of
dle. After hydraulic pressure is relieved, the rod the tensioner. This optimizes torque require-
bolt retains the tension. ments, but torquing the individual jackscrews
can be a very time consuming process.

Protective Cover

SuperNut Installation

Typical SuperNutTM shown below...

Jackscrews
Jackscrews Tensioner
Tensioner
1 12
11 1
10 2
3 4
9 3
8 4
2 7 5
6
Hardened Star Pattern Circular Pattern
Washer
Hardened Washer

Figure 56 The SuperNut tensioning system uses a series of jackscrews around the circumference of a
threaded tensioner to tension studs or bolts.

Page
35
 PEAK PERFORMANCE PRACTICES – LOWER WORKS

3) P&H TorqueRite™ Clamps use inner and TorqueRite clamps reduce bolt removal/instal-
outer sleeves to stretch rod bolts with hydraulic lation time up to 96%. They maintain proper
torque tools (Figure 57). The inner sleeve is torque even under high-vibration and they
threaded internally to fit onto the bolt, and reduce safety concerns with no actuator arm
externally to fit threads on the outer sleeve. required. As with the SuperNuts, no reaction
The outer sleeve performs all the work, pulling arm or nut retainers are required.
the bolt longitudinally. The clamping force is
achieved by counteraction of the sleeves. Like 4) A Standard Hydraulic Torque Wrench is
SuperNuts, protective covers keep debris away another means to attain the recommended pre-
from the clamps. load setting when mounting crawler frames to
the shovel carbody. This method requires keep-

TorqueRite Clamps Installation

Outer Sleeve
Inner Drive Slots Inner Sleeve
Sleeve

Outer
Sleeve

Bolt

The TorqueRite clamp pulls

the bolt longitudinally, with Washer with
all work performed by the Internal Splines
outer sleeve. Inner Sleeve-to-Washer
Splines
Figure 57 The P&H TorqueRite Clamp uses inner and outer sleeves to stretch rod bolts with
hydraulic tensioning tools.

Page 36
 5 – Lower Works Structural System

ers welded inside the carbody to prevent the

Side Frame Assembly Inspection
rod bolts from turning. When a new shovel is
purchased, if this is the specified tensioning Inspect the side frame assembly for:
method, keepers are factory-installed.
z Cracks in side frames and carbody
(shear ledge area especially)

Carbody and Side Frame z Tightness of side frame rod bolts

z
Inspection Gap between the carbody and
crawler frame shear ledge (front
Periodic inspections of the carbody and side and rear)
frames are recommended to check for structural
z Broken lube lines
cracks, tightness of side frame rod bolts, proper
lubrication, and the condition of propel machinery z Lubricant discharge
(Figure 58).
z Tightly belted propel transmission
Check for evidence of gross movement between (preload of bolts)
the crawler frame and carbody. There will be z Blower motors attached to motors
some movement but the gap between the frame and functioning
and carbody, on the horizontal shear ledge, should
not exceed 1/8 to 3/16 of an inch. Gap geometry z Motor coupling is not leaking, and
is different on a 4100XPB; therefore, a feeler teeth are not broken (uncouple, and
gauge will go in further than on other P&H visually inspect)
machines (over 2").
Gross movement between the crawler frame and Figure 58 Carbody and side frame inspection.
carbody will cause pounding out (material yield-
ing) of the shear ledge, bolt breakage and structur-
al cracking. If corrective action is not taken when
crawler frame movement is excessive, and bolt
breakage frequent, removal of the side frames will
be required, and the shear ledge will need to be
rebuilt.

Page 37
Page 38
6 - Operating Tips to Minimize Maintenance

Overview Motor Settings

Machine downtime for maintenance of lower Propel motor settings are established at the factory
works components and systems can be reduced for peak performance. Do not override the set-
with the operator’s assistance. Following are a tings.
few tips and techniques that can help.

Balancing the Shovel

Use of the Load Share Card A properly balanced machine means a properly
Even with dual propel shovels, propel loads are ballasted machine. Proper ballasting reduces over-
rarely distributed evenly over both crawler tracks. loading the front end of the machine and with it,
One propel motor or the other will develop more the front of the crawler system and structural sys-
torque than the other, pulling the shovel in that tem (Figure 59). Our research indicates that hav-
direction and creating greater stress on the lower ing too little counterweight on a shovel is more
components on that side of the shovel. As a result, harmful than having more than required.
propelling in a straight line can be difficult. To
address this issue,
P&H developed
“Load Share”. It is
highly recommended
for reducing crawler
component wear.
P&H Load Share
automatically adjusts
each propel control
frame and forces the
torque to relative
equilibrium. This
reduces propel skew-
ing to the left or right
in forward propel
mode. Besides reduc-
ing peak loads on one
crawler, it promotes
even loads on the
tracks and the tum-
blers.
Figure 59 A properly balanced machine will reduce stress on lower
components.

Page 39
 PEAK PERFORMANCE PRACTICES – LOWER WORKS

Shovels are designed to dig on nearly level tion the shovel to dig the material that could not
ground. Operation not consistent with the recom- be reached beyond the lines of the tracks.
mended safe gradability limits (see Service
Bulletin 89) will affect the loading on virtually
every component on the shovel. When working
outside these set limits and not complying with P&H MAX – An Effortless
OEM recommended procedures and maintenance
practices, accident, injury, or death could result. Way to Assure Peak
P&H recommends the following when propelling: Performance
• The shovel must have its boom, dipper han- Due to a lack of time, personnel or any number of
dles, and dipper attached reasons, various recommended machine inspec-
• Dipper handles must be horizontal and fully tions may be relegated to low status at a mine, or
extended with the dipper door open neglected altogether. Yet adhering to recommend-
• Propel brakes must be properly maintained ed inspection schedules could prevent unexpected
and adjusted parts failures, saving hundreds of thousands of
• The operator must be thoroughly familiar dollars in parts, service, and lost productivity.
with proper operating procedures To help fill such preventive maintenance voids,
• All mine safety practices and procedures must P&H offers a comprehensive inspection and eval-
be followed when propelling on maximum uation program called MAX, short for Machine
grades Auditing eXam (Figure 60). MAX helps assure
maximum profitability and minimum downtime
with a suite of six inclusive services that cover
Positioning the Shovel every square inch of the lower works. MAX’s six
evaluations:
Closely allied with proper balance is proper posi- • Factors evaluation
tioning of the shovel. Digging from too far away
• Preliminary audit
from the bank not only overloads the front of the
shovel; it is also a very inefficient use of digging • Dynamic inspection
power. • Electrical inspection
• Systems inspection
The shovel should be positioned with the front of
the crawlers close to the toe of the bank. The • Structural
operator can then propel forward until the inspection
crawlers reach the toe of the material.
Alternatively, the operator can position the handle
20° below horizontal with the handle protruding
two to four feet beyond the shipper shaft and pro-
pel forward until the dipper teeth almost touch the Figure 60 The
bank. MAX program
provides an
Dipper Strikes audit of every
Avoiding dipper strikes limits damage to the major
crawler shoes and front idlers. Depending on how component
big a problem it is, some mines have their opera- essential to
tors dig only between the tracks and then reposi- peak machine
performance.

Page 40
Lower Works Maintenance/Inspection
Summary
Keys to Prolonging Side Frame Assembly Inspection
Shoe and Pin Life
Inspect the side frame assembly for:
z Use induction hardened pins. z Cracks in side frames and carbody
z Lubricate pins at the time of (shear ledge area especially)
installation. z Tightness of side frame rod bolts
z Trim toenails, side flow, and pin eye z Gap between the carbody and crawler
metal flow before interference occurs. frame shear ledge (front and rear)
z Replace broken pins promptly. z Broken lube lines
z Maintain proper track tension and z Lubricant discharge
pitch.
z Tightly belted propel transmission
z Replace worn tumblers. (preload of bolts)
z Do not use new shoes with used z Blower motors attached to motors and
rollers or tumblers. functioning
z Maintain a smooth pit floor. z Motor coupling is not leaking, and
teeth are not broken (uncouple, and
(Also shown on page 22.)
visually inspect)

(Also shown on page 37.)

Crawler System Inspection

Periodic inspection of the crawler system z Cracking and missing material at the
includes visual checks for: ends of the roller path (excessive toe
z Drive tumbler/shoe engagement nailing)
z Loose or missing crawler shoe pin z Roller path collapse
keepers z Excessive tension or slack in the
z Pin rotation crawler belt
z Broken pin (pin cocked or distorted in z Condition of tumbler lugs
the pin bore) z Spalling of lower rollers (especially
z Pin bore wallowed out corners of tread)
z Excessive wear (elongation) of shoe z Color and quantity of grease expelled
pin eyes from tumbler, rollers, and idlers
z Broken shoes (wings/pin lugs) z Contact between rollers and crawler
z Binding between shoes (inspect the
frame rails
ends of the roller path for binding z Worn guide rails (shoe contact with
between adjacent shoes as viewed as carbody)
they wrap around the tumbler) z Excessive side frame wear

(Also shown on page 30.)

Page 41
Page 42
Glossary

BRINNELL HARDNESS (BHN) – A standard- sion. Another aspect of the drive is that it uses a
ized system for measuring the medium range of smaller drive tumbler compared to low drives, and
metal hardness by hydraulically pressing a hard a smaller number of shoes are engaged with the
ball under a standard load into the specimen and tumbler at any given moment. Fewer shoes in
measuring the diameter of the indent. Rockwell engagement means less sensitivity to shoe pitch
“C” is a system for measuring high hardness. elongation.
BUSHING – A cylindrical metallic sleeve or liner IDLER – A large roller placed in a track system to
used to reduce friction and abrasion in a pin-con- transmit motion and force without changing speed
nected joint. but enabling a change in direction.
CARBODY – A weldment that serves as the sup- LINK PIN – The central part of a fastening sys-
porting frame of a shovel, similar to a chassis. tem used to connect one crawler shoe to another; a
cylindrical member that enables rotary motion
CRAWLER SYSTEM – A combination of rollers, between one shoe and an adjacent shoe.
idlers, tumblers and tracks that enable a heavy
piece of equipment to propel over rough terrain. LOAD SHARE CARD – An electrical control
system upgrade inherent to P&H control that
GROUND BEARING PRESSURE (OR reduces variance in propel loads between the two
SIMPLY GROUND PRESSURE) – The pressure crawler tracks when propelling straight ahead.
(force/area) exerted under a crawler track due to
the total weight of a shovel, expressed as lbs/in2 LOW DRIVE – A drive system configuration in
(kg/cm2). Ground pressure can be reduced by using which the drive tumblers are mounted close to the
wider tracks, thus distributing the shovel’s weight ground. All machinery is spur gear type, much of it
over a larger surface area. Ground bearing pressure exposed to wear and contamination. Low drive
can be measured as static or dynamic, average or was superseded by high drive in the 1980s.
peak. Specifications normally refer to average
static ground pressure. LUG – A tumbler lug engages in a recess of a
crawler shoe while the shoe lug engages in a
GUIDE RAIL – Replaceable castings or structural recess of the tumbler.
plates that are either pinned or welded to the top of
the crawler frames to support and guide the MAX – A Machine Auditing Examination service
crawler track. The crawler tracks are normally developed by P&H to keep equipment operating at
loose on top, which means the weight of the shoes peak performance levels.
must be supported or they will contact the carbody. PIN – See “link pin”
HIGH DRIVE – A drive system configuration in PIN KEEPER – A bolt-on retainer that keeps the
which the drive tumblers are mounted high on the link pin from disengaging from the two shoes it
track frame. P&H introduced its high drive system connects.
in the late 1980s along with a planetary transmis-

Page 43
 PEAK PERFORMANCE PRACTICES – LOWER WORKS

PITCH – The linear distance measured from the SUPERNUT™ – A privately labeled threaded nut
center of one crawler shoe link pin to the center of system that enables a very large bolt to be pre-
the adjacent crawler shoe link pin while under ten- loaded using a series of very small bolts, thus sim-
sion. Pitch changes over time due to wear, stretch plifying the process; one of several types of fasten-
and deformation of the shoe in general. ers used to secure shovel components together,
most notably to fasten a shovel’s side frames to its
PITCH MISMATCH – A condition in which the carbody.
crawler shoe pitch and tumbler drive pitch are out
of sync caused by the stretching of a shoe’s pitch THRUST WASHER – A metal washer placed
due to wear. between two moving parts to prevent longitudinal
movement and provide a bearing surface for the
PITCH RANGE – The variation in circular dis- thrust surfaces of the parts; a hardware member
tance over which a crawler shoe will mesh proper- that resists or absorbs axial loading.
ly with a drive tumbler.
TOE NAIL – A thin, wedge-shaped projection of
PRELOAD – The tension created in a fastener metal on a crawler shoe’s roller path caused by the
when it is first tightened. Preload can be reduced flow of metal during the work hardening of man-
over time due to localized yielding, vibration, or ganese; a condition unique to crawler shoes, which
creep. can cause cracking if left unattended.
PROPEL SYSTEM – A drive system comprising TORQUERITE™ – A bolt fastening system that
controls, motors, gear reducers, output shafts and a uses inner and outer sleeves to stretch rod bolts
track system to enable a piece of equipment to tra- with the speed of a hydraulic torque wrench but
verse over terrain. without the need of a nut retainer or reaction arm.
ROD BOLT – A bolt threaded at both ends, used TRACK TENSION – The preload created in the
to secure a shovel’s side frame to its carbody. track system by pushing the front idler outward
ROLLER – A round member used in sets to sup- and re-shimming. Track tension can be very harm-
port the weight of the shovel and distribute its ful to track shoes if it is set too high or too low.
weight over the track shoes. TUMBLER – The large wheel-like component at
SHEAR LEDGE – The joint between the carbody the rear of a shovel that engages with the crawler
and crawler frames, configured to transfer vertical shoes converting rotary torque into linear track
forces from the carbody to the side frames. movement to propel the shovel forward and in
reverse. The tumbler may incorporate lugs or
SIDE FRAMES (SAME AS CRAWLER sprockets that mesh with the shoes.
FRAME) – Two large symmetrical structural com-
ponents mounted to the carbody and on which the V-BRAKE – An open style brake used on earlier
crawler tracks are mounted. P&H shovels that uses a V-shaped rotary member
held from rotation by a V-shaped shoe that wedges
STRUCTURAL SYSTEM – The components into the brake wheel to magnify frictional force.
that make up the skeleton of a shovel; the carbody
and side frames.

Page 44
Index

Air system . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 Motor repair . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Back bending . . . . . . . . . . . . . . . . . . . . . . 23, 25 P&H MAX . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Brake . . . . . . . . . . . . . . . . . . . . . . . . . 4, 8-10, 32 Pin (link pin) . . . 12-19, 16-21, 22-27, 29, 30, 32
V-type . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Bore . . . . . . . . . . . . . . 13, 16-19, 23, 24, 30
Disc . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8, 9 Keeper . . . . . . . . . . . . . . . 16, 18, 19, 24, 30
Springs . . . . . . . . . . . . . . . . . . . . . . . . . . 8, 9 Pitch . . . . . . . . . . . . . . . . . 11-16, 18, 19, 22, 30
Upgrade . . . . . . . . . . . . . . . . . . . . . . . . 9-10 Roller . . . . . 11, 15, 19, 20, 22-24, 25-28, 30, 31
Bushing . . . . . . . . . . . . . . . . . . . 1, 4, 26-28, 31 Path . . . . . . . . . . . 15, 16, 19, 22-25, 29, 30
Carbody . . . . . . . . . . . . . . . . 1, 3, 30, 33-35, 37 Crush . . . . . . . . . . . . . . . . . . . . . . . . .23-25
Crankshafting . . . . . . . . . . . . . . . . . . . . . . . . 10 Geometry . . . . . . . . . . . . . . . . . . 13, 23, 24
Crawler . . . . . 1-3, 6, 7, 11-16, 16, 18-20, 22-27, Selection . . . . . . . . . . . . . . . . . . . . . . . . . 26
29, 30, 33, 34, 37, 39, 40 Shear ledge . . . . . . . . . . . . . . . . . . . . 33, 34, 37
Belt (track) . . . . . . . . . . 3, 4, 6, 7, 11-14, 17, Shoe . . . . . . . . . . . . . . . . . . . . 11-27, 29, 30, 40
19-25, 28, 30, 39, 40 24J . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Frames (see side frames) . . . . 1, 3, 6, 20, 22, ADS . . . . . . . . . . . . . . . . . 13, 14, 17, 24, 27
24-27, 29, 30, 31, 33, 34, 37 Belt . . . . . . . . . . . . . . . . . . . . . 7, 11, 12, 15,
System inspection . . . . . . . . . . . . . . . . . . 30 19, 20, 22, 23, 25, 30, 33
DELTA . . . . . . . . . . . . . . . 13, 14, 17, 19, 24, 27 Identifying problems . . . . . . . . . . . . . . 22-25
Differential steering . . . . . . . . . . . . . . . . . . . . . 4 Lug . . . . . . . . . . . . . . . . . . . . . 11-25, 27, 30
Dipper strike . . . . . . . . . . . . . 15, 19, 24, 28, 40 R Series . . . . . . . . . . . . . . . . . . . . . . . 14, 17
Drive shaft . . . . . . . . . . . . . . . . . . . 3, 4, 6-8, 31 Wing . . . . . . . . . . . . . . . . . . . . . . . . . 24, 30
Upgrade . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Side frames . . . . . . . . . . . . . . . . . 1, 3, 6, 20, 22,
Dual propel . . . . . . . . . . . . . . . . . . 2, 3, 4, 9, 39 24-27, 29, 30, 31, 33, 34, 37
ENCORE® . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Fasteners . . . . . . . . . . . . . . . . . . . . . . 34-37
Ground pressure . . . . . . . . . . . . . . . . . . . . . . 15 Thru hardening . . . . . . . . . . . . . . . . . .17, 18, 27
Guide rail . . . . . . . . . . . . . . . . . . . . . . 11, 29, 30 Toe nail . . . . . . . . . . . . . . . . . . . . . . . . . . 23, 30
High drive . . . . . . . . . . . . . . . . . . . . . . . 2, 3, 17 Track tension . . . . . . . . . . . . . 12, 14, 19-22, 30
Idler . . . . . . . . . . . . . . . 11, 19, 20-22, 25-31, 40 Adjustment . . . . . . . . . . . . . . . . . . . . 19, 20
Upgrade . . . . . . . . . . . . . . . . . . . . . . . . . 28 Transmission . . . . . . . . . . . . . . . 4, 6, 7, 8, 10, 37
Induction hardening . . . . . . . . . . . . . . 17, 18, 22 Planetary . . . . . . . . . . . . . . . . . . . . . . . . 4, 6
Injector . . . . . . . . . . . . . . . . . . . . . . . . . . 31, 32 Spur gear . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Load share card . . . . . . . . . . . . . . . . . . . . . . . 39 Repair . . . . . . . . . . . . . . . . . . . . . . . . . . 6, 7
Low drive . . . . . . . . . . . . . . . . . . . . . 1, 2, 4, 17 Tumbler . . . . . . . 6, 11-15, 19-22, 28, 30, 31, 39
Manganese . . . . . . 15, 16, 19, 22, 23, 25, 27, 29 Work hardening . . . . . . . . 15, 16, 19, 23, 27, 29

Page 45
 Additional Peak Performance Practices handbooks in this series:

XS-1525-1 XS-1755 XS-2219 XS-2321

Peak Performance Peak Performance Peak Performance Peak Performance
Practices Practices Practices Practices
Wire Rope Dippers Excavator Selection Electric Mining Shovel
DC Motors

Suggestions, Ideas?
It is our hope that you have found the information in this publication helpful. Since each mine is unique and has its
own methods of operation we encourage you to share your suggestions, tips or techniques that other mines might find
helpful for achieving peak performance from electric shovel lower works components. We would be pleased to consid-
er them for inclusion in a future edition. Please e-mail your suggestions or comments to P&H Mining Equipment at
ph-min@phmining.com, or call us at (414) 671-4400.
 MinePro Services Answers Your Call
To “Walk A Mile In My Shoes…”
With our people working every day in mines worldwide, you can count on P&H MinePro
Services to understand your challenges from your point of view. In fact, a large number of our
service representatives have come to us with years of first-hand experience as fulltime employ-
ees in mining operations like yours.
When you need a reliable partner to go the extra mile to meet your needs, contact your local
P&H MinePro Services office. We’re ready to meet your needs with products and support ser-
vices that provide for the total life cycle management of your shovels’ crawler shoes and drive
systems.
• Long-life, low-maintenance ADS and DELTA drive systems
• Lug-type and sprocket-type tumblers
• Induction hardened link pins
• Bushings and thrust washers
• 50+ Rollers
• Idlers
• Upgrades
• Shoe failure analysis
• Maintenance contracts
• Operator and maintenance
training

For further information, contact your local P&H MinePro® Services representative or call 1-888-MINEPRO.
Outside the U.S. and Canada, phone (414) 671-4400 or fax (414) 671-7785. Visit us on the internet at
www.minepro.com.

Note: All designs, specifications and components of equipment described above are subject to change at manufacturer's sole discretion at any time
without advance notice. Data published herein is informational in nature and shall not be construed to warrant suitability of product for any particular
purpose as performance may vary with conditions encountered. The only warranty applicable is our standard written warranty for this product.
P&H Mining Equipment, P. O. Box 310, Milwaukee, Wisconsin 53201

XS-2922 5FP-705