Grove Training Institute

Section 3

Crane Hydraulic Symbols

Crane Terms and Nomenclature

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GROVE
HYDRAULIC
SYMBOLS
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Table of Contents

Introduction

Hydraulic Symbols Pages 1-1 through 1-19

Memory Challenge Page 1-20

Glossary Page 1-21 to 1-22

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Grove Hydraulic Symbols
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Introduction
The Grove crane schematic study guide has been developed to equip a
novice technician with navigational skills necessary to use system schematics.
The content of the handbook is intended to increase a technicians general
knowledge level of Grove hydraulic schematics. Schematic symbols emphasize
the function and describe the operation of the components and their respective
circuits. an overall system schematic will show the entire machine’s circuitry
on one or in some cases, multiple pages. A technician equipped with the ability
to read schematics has the advantage of viewing the cranes complete hydraulic
circuit. When presented with a machine fault, they can systematically eliminate
possible causes, thus arriving at a solution much quicker. It is beneficial to a
technician to have the fundamental understanding of schematic symbols in
order to become an effective troubleshooter.

This study guide and the information contained here in was developed based on
ISO - 1219 Fluid Power and ANSI - Y32.10 Graphic Symbols.

Further information on this study guide or other related material may be

obtained by contacting the Grove Training Institute at.

Grove Worldwide Headquarters

Grove Training Institute
P.O. Box 21
1565 Buchanan Trail East
Shady Grove, PA. 17256

Telephone: 1-717-593-5316
Fax: 1-717-593-5059
Email: www.grovetraining@groveworld.com

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Description Symbol

Reservoir: The hydraulic reservoir is designed to

store, cool, and clean the machines hydraulic oil
supply. The vented reservoir allows atmospheric
pressure to push the oil into the hydraulic pumps
inlet ports.

1. 2.
Hydraulic Return Lines: Are either terminated,
1. below fluid level, 2. above fluid level.
Grove terminates below fluid level to prevent excess
air in system.

Grove Hydraulic Symbols 1-1

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Description Symbol

Pumps: Hydraulic pumps convert mechanical

energy transmitted by a power source, into
hydraulic working energy, flow. form 1 27.7
Grove uses a fixed positive displacement 26.5
gear pump in most of its mobile hydraulic
systems, as shown in form 1.
In some applications a variable
displacement pump may be used, form 2.

form 2

Power Source: A power source can be in the

form of a combustion engine, form 1 or form 1
electric motor form 2.
Both provide power to operate the hydraulic pumps.
Either as a main power source or an emergency
backup.

form 2 M

Grove Hydraulic Symbols 1-2

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Description Symbol

Hydraulic Motors: Convert the working energy

of the hydraulic system into mechanical energy.
Hydraulic motors are positive displacement and are
either Vane, Gear or Piston. form 1
These motors are installed in the hoist circuit, vane,
piston, and the swing circuit, gear, on a Grove crane.
Schematic symbol for the Unidirectional, form 1
and the BI - directional. form 2

form 2

Pump Disconnect: Used to disconnect pump

from power source, for extended travel, repairs,
cold weather starts.

Grove Hydraulic Symbols 1-3

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Description Symbol

Continuous Line: Supply line or Return Line.

Depending on direction of oil flow.

Connecting Lines: Branch lines connected

to main line.

Lines Crossing: A line crossing over another

line, but not connected.
Note: This symbol has been removed from
latest Grove schematics.

Dashed Line: Pilot Pressure.

Grove Hydraulic Symbols 1-4

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Description Symbol

Dotted line: Case drain or load sense

Chain Line: Enclosure of two or more functions

contained in one unit.( outrigger control)

Pressure Transducer: Is a hydraulic / electrical

WWW

device located in the lift cylinder circuit.

It is used in conjunction with the cranes load
moment indicator system, (L.M.I.).

Grove Hydraulic Symbols 1-5

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Description Symbol

Filter: Removes contamination from hydraulic

system.

Filter with Bypass Valve: The bypass valve allows

the oil to bypass the filter if it is plugged or the oil is
too thick to pass through filter.
W
25

Accumulator: Used in a hydraulic circuit to either

develop system flow or absorb system shock.
Grove normally uses a hydro-pneumatic accumulator.
This type uses compressed gas to apply force to the
liquid.
Most accumulators are charged with nitrogen gas.

Grove Hydraulic Symbols 1-6

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Description Symbol

Check Valve: Is designed to create back pressure

in a specific circuit. Swing, Oil Cooler. W

Orifice: An in line fixed restriction, that functions

as a flow control device. Designed to reduce
pressure and oil flow in specific circuits.

Adjustable Orifice: An inline restriction that

functions as a flow control device, this device is
manually adjustable for fine tuning pressure and
flow rate.

Hydraulic Oil Cooler: Because of viscosity,

friction, and changing direction, hydraulic oil
generates heat during operation. To keep the oil
within the required operating temperature range
air coolers are installed in the system to aid in
the cooling process.

Grove Hydraulic Symbols 1-7

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Description Symbol

Temperature Switch: An electric switch that

regulates the temperature of the hydraulic 100o
oil.

W
Hydraulic Pressure Switch : Senses hydraulic
pressure for the purpose of energizing electrical 125
components. (relay coils, indicator lights) PSI

Flow Switch: Provides ground for a specific W

electrical circuit, shown in normal position it X
will illuminate an indicator light indicating a fault.
When operating properly oil flow will enter the
valve and at the same time as pressure builds in
pilot line shifting the valve spool open thus opening
the switch contacts and turning off indicator light.

Grove Hydraulic Symbols 1-8

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Description Symbol

Relief Valve: Installed in a hydraulic

W
2500
circuit to protect the system from being
over pressurized.

W
Pressure Reducing Valve: Regulates max
pressure allowed into individual circuits.
(swing brake, function controllers)
250 PSI

Shuttle Valve: The inlet port connected to

the high pressure is automatically connected to
IN IN
the outlet port, while the other port is closed.
Used to direct maximum pressure to components
OUT
depending on application.

Grove Hydraulic Symbols 1-9

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Description Symbol

Manually Operated: Two way valve, the oil flow

has two paths to travel, in the neutral position as
shown, the oil, once enough pressure is built to
unseat the check, the oil can flow to tank.

W
Pneumatic: One position valve, once the spool is shifted,
the oil has a path to flow to function, in the neutral
position flow is blocked.

Pilot: Operated one position valve, same as pneumatic

operated valve, only the spool is shifted by pilot oil.
W

Grove Hydraulic Symbols 1-10

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Description Symbol

Electric Operated: Two way valve, once the

spool is shifted the oil has two paths to travel,
to the specific circuit and a path for oil to return
to tank.

W
Electric Operated: One position valve, once the spool is
shifted, the oil has a path to flow to a function, in the
neutral to flow is blocked, this spool is shifted
electrically.

Brake Valve: Supplies hydraulic oil to swing brake

assembly to assist the springs to apply pressure to
stop the rotation of the superstructure, during crane to
operation. swing
brake D
p
W

Grove Hydraulic Symbols 1-11

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Description Symbol

. control lever

W
Open Center Cylinder Spool: Used in the
directional control valve that controls oil flow
to and from a cylinder function. When in the
neutral position, as shown here, the oil is trapped
in the circuit. With the crane running and the gear
pump engaged, and the spool is in neutral position, B A
the oil will flow through the center of valve (A) and
returned to tank (B). This spool is shifted with a
control lever.
(outriggers, lift, telescope)

W
W

Open Center Motor Spool: Used in the

.
directional control valve that controls oil flow
to and from a hydraulic motor function. When in
the neutral position, as shown here, the circuit is
open to a return line to tank. This prevents
build up of hydraulic oil back pressure in the
motor circuit.
( hoist, swing)
W

Grove Hydraulic Symbols 1-12

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Description Symbol

pilot pressure

W
Closed Center Cylinder Spool: Used in a
pressure compensated directional control valve that
controls oil flow to and from a cylinder function,
oil in the cylinder circuit is trapped in the circuit
when the spool is in the neutral position. But
unlike the spool on p 1-12, if no functions are
being operated the oil cannot pass through the
center of the valve back to tank,instead unloader
valve cartridge.
This spool is shifted with hydraulic pilot pressure.

W
( lift, telescope)

Closed Center Motor Spool: Functions the same

as the closed center cylinder spool above,
except that this spool has a open port for oil flow
back to tank. This prevents build up of back
pressure in the motor circuit.
W

Grove Hydraulic Symbols 1-13

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Description Symbol

Single Acting Cylinder: Can be extended

hydraulically or pneumatically depending on
application. The cylinder is retracted
utilizing
a spring.
(axle disconnect, park brake,).

Double Acting Cylinder: Extended and

retracted hydraulically.
(steer).

B
Double Acting Telescope Cylinder: With A
W

holding valve. EXTEND

The rod of the cylinder is anchored, as oil flow RETRACT
unseats the one way check valve in the holding
valve (A),the oil flow to the piston side of the
cylinder (B) filling up with oil, causing the barrel
to move outward, the boom section that it is
anchored to is pushed outward.

Grove Hydraulic Symbols 1-14

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Description Symbol

Trombone Telescope Cylinder: With B

holding valve. The trombone cylinder is W

utilized in the four section synchronized C

sequenced boom. (RT 635c, TMs 875c)
R
This design allows for one controller
operation of extension and retraction of the
boom sections. The cylinder barrel moves P
the inner-mid out until it is fully extended.
By way of a sequence valve the oil flow is
A
then routed to a double acting cylinder
which extends the outer-mid out, at the same
time the fly is extended by cables.

Multi - Stage Telescope Cylinder:

w

With holding valve. The multi-stage

cylinder is used in the three section
synchronized sequenced boom. (500E &
600E series cranes) It’s design eliminates
the need for two individual cylinders to
extend and retract the boom sections

Grove Hydraulic Symbols 1-15

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Description Symbol

Holding Valve: Used in the lift, telescope

circuits, the primary function of the holding
valve is to trap the oil on the piston side of
the cylinder, when the boom in the raised
position or the boom sections extended.
They also trap the oil in the piston side of the
P
)
cylinder in case of a hose failure if the boom )
is raised or extended. Holding valves are
adjustable and protect the cylinder form

W
becoming over pressurized due to thermal
expansion of the oil, when cylinder is fully V
extended.
G
Holding
Valve

Inverted Outrigger Stabilizer:

With pilot operated check valve.
Used to raise the crane off the ground when
the cranes on outrigger lifting chart.
The pilot operated check traps oil in the piston
side like the holding valve, only they do not
have thermal relief protection and are not
adjustable.
(outrigger circuit)

Grove Hydraulic Symbols 1-16

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Description Symbol

4000
Pilot Operated Check Valve: With thermal relief.
PSI D
The pilot operated check valve requires pilot
pressure to unseat the one way check to allow the P W
oil to escape from the piston side of the cylinder
and return to tank. This valve is not adjustable. W
(outrigger circuit) V C

17.6 GPM
8 GPM
REG BP W 2500
Flow Divider Valve: Regulates oil flow to a PSI
selected circuit. DR
(Steering, Swing)
W
(
(
IN

25.6 GPM

Grove Hydraulic Symbols 1-17

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Description Symbol

4 2 6 3 1 5 9 8 12 7 10 11
Hydraulic Swivel: The hydraulic swivel is
designed to allow 360 degree rotation, while
supplying oil to all superstructure functions. 2 10
5 7
3 12
1 8
4 9
6 11

Hoist Brake: Used to hold the load after

hoist control is returned to neutral, in order
WWWV

VWWW
to keep the load from drifting the brake is
applied in the hoist up mode, this is
accomplished by turning through a sprag
clutch, which is splined to the disc and will
only turn in one direction. To lower the load
the brake will be released, the hoist motor
control valve controls the speed of the hoist
drum in the down mode. The brake is spring
applied and hydraulically released.
M
WW

WW

Swing Brake: Used to stop the rotation of

the superstructure during crane operation.
The swing brake is spring applied and
hydraulically released.

Grove Hydraulic Symbols 1-19

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Memory Challenge :
From memory identify the following symbols.
(refer to book only if necessary)

1. IN IN

OUT

W
2. X
W

3.
250 PSI
W

2500

4.

5. What type of accumulators does Grove normally use, and what are they precharged with ?
, .

Grove Hydraulic Symbols 1-20

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Glossary

A M
Accumulator 1-6 Motors 1-3

B
Hoist Brake 1-19 O
Swing Brake 1-19 Orifice 1-7
Oil Cooler 1-7
C
Single Acting Cylinder 1-14 P
Double Acting Cylinder 1-14 Pumps 1-2
Telescope Cylinder 1-14 Power Source 1-2
Trombone Cylinder 1-15
Multi-Stage Cylinder 1-15
Lift Cylinder 1-16 R
Stabilizer Cylinder 1-16 Reservoir 1-1
Termination of return
D lines 1-1
Disconnect (pump) 1-3
S
F Open center cylinder
Filter 1-6 spool 1-12
Filter with bypass valve 1-6 Open center motor
spool 1-12
L Closed center cylinder
Continuous Line 1-4 spool 1-13
Connecting Line 1-4 Closed center motor
Crossing Line 1-4 spool 1-13
Dashed Lines 1-4 Swivel 1-19
Dotted Line 1-5 Switches 1-8
Chain Line 1-5

Grove Hydraulic Symbols 1-21

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Glossary

T
Transducer 1-5

V
One way check valve 1-7
Relief valve 1-9
Pressure reducing valve 1-9
Shuttle valve 1-9
Manually operated two way
valve 1-10
Pneumatic operated one way
valve 1-10
Pilot operated one way valve 1-10
Electric operated two way valve 1-11
Electric operated one way valve 1-11
Brake valve 1-11
Holding valve 1-16
Pilot operated check valve 1-17
Flow divider valve 1-17

Grove Hydraulic Symbols 1-22