CHAPTER 1

INTRODUCTION

India has the highest number of road accidents in the world. With over
130,000 deaths annually, the country has overtaken China and now has the worst
road traffic accident rate worldwide. This has been revealed by the World Health
Organization (WHO) in its first ever Global Status Report on Road Safety. The
report pointed to speeding, drunk driving and low use of helmets, seat belts and
child restraints in vehicles as the main contributing factors.
In any accident scene, rapid removal of the casualty to hospital improves
their chances of survival. The term the Golden Hour was first introduced in
1961, but because of misinterpretation as to what period this actually referred to, a
second concept, the Platinum Ten Minutes" was proposed as the time taken to
move a casualty to the ambulance.
A faster method to remove the victims trapped in the vehicle is required as
the traditional methods are time consuming . The process of removing a vehicle
from around a person who has been involved in a motor vehicle accident is
commonly known as Vehicle extrication. Rescue personnel use a number of tools
to extricate victims. There are two main types pneumatic and hydraulic.
The objective of this project is to fabricate a rescue tool called hydraulic
jaws to shear apart vehicle parts and also to lift heavy materials so as to save
victims trapped under slabs during earthquakes. It is designed with low operating
sound so that the victims are not stressed while its working.

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CHAPTER 2
DESIGN AND WORKING
2.1 Schematic Diagram

SL no

PARTS

1.

Jaws

2.

Slot

3.

Hinge of Jaws

4.

DC Motor

5.

Connecting Rod

6.

Casing

7.

Hydraulic Jack

8.

Handle

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Table 2.1 Parts Of Hydraulic Jaws

Fig 2.1 Schematic diagram of Hydraulic Jaws

Fig 2.2 Front View

Fig 2.3 Side View

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Fig 2.4 Top View

Fig 2.5 Isometric View

2.2 Working
Hydraulic jaw comes under Class 1 lever in which the fulcrum (levers
point of rotation) is between the effort and the load. It utilizes a six-bar linkage in
which the vertical motion of the piston is transferred to the two hydraulic jaws
using the links. It is a hydraulic tool designed with two arms which come together
in a narrow tip and which uses pressure from a hydraulic jack to separate or
spread the arms . The tip of the tool can be inserted into a narrow gap between two
vehicle panels such as between two doors , or between a door and a fender . When
the tool is operated , the arms are opened , pushing apart the metal in the panels
.Spreaders may also be used to pop vehicle doors from their hinges.
The force required to lift the piston is provided by the hand operated
hydraulic jack and this force is transferred to the jaws using the links which result
in spreading of the jaws and this motion can be utilized for shearing apart metal.

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CHAPTER 3
COMPONENTS

3.1 Angle Iron & MS Flat

Structural steel is a category of steel used as a construction material for
making structural steel shapes. A structural steel shape is a profile, formed with a
specific cross section and following certain standards for chemical
composition and mechanical properties. Most steels used throughout Europe are
specified to comply with the European standard EN 10025.The normal yield
strength grades available are 195, 235, 275, 355, 420, and 460, although some
grades are more commonly used than others e.g. in the UK, almost all structural
steel is grades S275 and S355.

Fig 3.1 Angle Iron

Fig 3.2 M S Flat

Fabricating flat plate is performed on a plate processing centre where

the plate is laid flat on a stationary 'table' and different cutting heads traverse the
plate from a gantry-style arm or "bridge." The cutting heads can include a punch,
drill or torch.

3.2 Nut & Bolt

A nut is a type of fastener with a threaded hole. Nuts are almost always
used opposite a mating bolt to fasten a stack of parts together. The two partners

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are kept together by a combination of their threads' friction, a slight stretch of the
bolt, and compression of the parts.

Fig 3.3 Nut

A bolt is an externally threaded fastener designed for insertion through
holes in assembled parts, and is normally intended to be tightened or released by
torqueing a nut. An externally threaded fastener which is prevented from being
turned during assembly and which can be tightened or released only by torqueing
a nut is a bolt.

3.3 MS Rod
Fig 3.4 Nut and Bolt
Mild steel also known as plain-carbon steel, is now the most common
form of steel because its price is relatively low while it provides material
properties that are acceptable for many applications. Low-carbon steel contains
approximately 0.050.25% carbon making it malleable and ductile. Mild steel has
a relatively low tensile strength, but it is cheap and easy to form; surface hardness
can be increased through carburizing. Low-carbon steels suffer from yield-point
runout where the material has two yield points. The first yield point (or upper
yield point) is higher than the second and the yield drops dramatically after the
upper yield point.

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Fig 3.5 MS rod

3.4 Hydraulic Jack
A bottle jack is a hydraulic jack which resembles a bottle in shape,
having a cylindrical body and a neck, from which the hydraulic ram emerges. In a
bottle jack the piston is vertical and directly supports a bearing pad that contacts
the object being lifted. With a single action piston the lift is somewhat less than
twice the collapsed height of the jack, making it suitable only for vehicles with a
relatively high clearance.

Fig 3.6 Hydraulic Jack

3.5 Jaw
It is one of the main working parts of the Hydraulic jaw. Jaws are
made of mild steel.The mild steel used to make this jaw is of thickness 1.5 inch
that is about 36mm thickness. Being mild steel the jaws are bulky. A step cut is
given at the top end of the jaw to make it easier to enter in to the gap for spreading

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purpose.

Fig 3.7 Jaws

3.6 Seating
Seating is one another major part of the Hydraulic jaw. Jaws are hinged
to the seating with the help of nut and bolts. Piston is moved up and down through
the hole in the center of the seating. So now we get the idea that seating gives the
structure and shape. Seating is made of mild steel. Properties of mild steel are
mentioned earlier. Mild steel used here is of thickness 3 inch that is about 50mm
thicknes.The length*breadth*height of the seating is about 120mm*80mm*50mm.

3.7 MS Piston Rod With Prism Head

Fig 3.8 Seating
. The prism head of piston is made of mild steel .Thickness of the mild
steel used here is about 36 mm. The MS rod is welded to the prism head and there

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is two holes on the prism head for bolts.

Fig 3.9 M S piston rod with prism head

3.8 MS Cylindrical Collar & Pin
A mild steel cylindrical collar is used to connect Hydraulic Jacks piston to
the MS rod piston. The collar is bolted to the MS piston rod using a pin which can
be fastened using Allen key.

Fig 3.10 M S cylindrical collar and pin

3.9 Links
Links are the main part which is used to connect the Jaws and the piston
rod. They convert vertical movement of piston into horizontal (or sidewise)
movement of the jaws. The holes on links used here are of two different
diameters. They are 16mm on piston side and 20mm on jaw side respectively.

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Fig 3.11 Links

3.10 Base
Hydraulic jack is placed on the base. Base is made of MS flat and angle
iron. It is made so that jack can be held rigidly. It provide support for seating and
also for hydraulic jack.

Fig 3.124 Base

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CHAPTER 4
OPERATIONAL EXPLANATION
Hydraulic pressure: The hydraulic jaw is mainly powered by hydraulic
pressure exerted from the hydraulic bottle jack (which is mainly used in auto
motives). The hydraulic jack is an example of hydraulic press where it uses
Pascals law (pressure is equally distributed over a fluid). Consider the following
figure

Fig 4.1 Figure showing Pascals Law

Here two pistons are connected to two mutually connected chambers
which are filled with incompressible fluid (which is denoted by blue color). Let
the cross sectional areas of piston 1 and piston 2 are A1 and A2 respectively; their
corresponding forces are F1 and F2
By Pascals law pressure distribution is same in both the chambers then,
F1/A1 = F2/A2
implies F2 = (A2/A1)*F1
Since A1<< A2, F2>>F1
Which implicate that with the small applied force on piston 1, we get bigger
vertical force.Lets get back to the hydraulic jack here, on the other hand
displacement of piston 1 is greater (which equal to (A2/A1) times of piston it is
because the volume change after displacement are for both pistons are same
(incompressible fluid Never compresses hence it makes volume change to nullify
the effect)

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Fig 4.2 Side and Front View of hydraulic Jack

Table 4.1 Parts of the hydraulic Jack

SLNO:
1.
2
3.
4.
5.
6.
7.

NAME OF PARTS
Top Cap
Adjustment Screw
Oil Tight tank
Oil plug
Cylinder
Piston rod
Backing

SLNO:
8.
9.
10.
11.
12.
13.
14.

NAME OF PARTS
Oil Drain valve
Hydraulic Fluid
Pressure at the hand
Pump Casing
Pump plunger
Handle
Safe valve

Hydraulic bottle jacks works in the same principle of hydraulic

press, but it varies from press in the case of mode of application of

hydraulic

pressure. In the bottle jack the hydraulic pressure is not applied continuously but it
applied step by step (built-up hydraulic pressure).The piston rod of the jack makes
displacement with a set pumping actions by pump plunger .In each action the
piston moves a certain displacement and stops, hydraulic fluid flow from reservoir
oil tight-tank to cylinder is temporally restricted

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Fig 4.3 Suction of hydraulic fluid from the reservoir

Fig 4.4 Pumping of hydraulic fluid from plunger chamber to piston cylinder
When the piston rod of hydraulic jack reaches the maximum height , it
can be put back into initial position(after the use of the jack ) by turning oil drain
valve anticlockwise. This valve enables a bypass path to oil tight-tank from piston
cylinder, thus the oil refills in the reservoir. After this operation the oil drain valve
is turned clockwise in order to close the path.

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CHAPTER 5
COST ESTIMATION

Table 5.1 Cost Estimation

SL NO:

PARTICULARS

QUANTITY

COST/UNIT:

TOTAL
COST

1.

930

930

1
1
1

200
200
1020

200
200
1020

1
4

475
120

475
480

100

200

8.

50

100

9.
10.

1
1

750
20

750
20

2.
3.
4.
5.
6.
7.

MS Plate 50mm thick

MS Rod
MS flat
MS plate 36mm thick
Angle iron
Nut and bolt 20mm dia
Nut and bolt 16mm dia
Nut and bolt 12mm dia
Hydraulic jack
Collar pin

CHAPTER 6

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CALCULATIONS
6.1 Maximum Load Calculation

Fig 6.1 Force Diagram

Maximum force acting on link,
Assume maximum angle displacement between links , =80
<COE = ( ) = 90-40 = 50
F = 5000N
Resolving the forces F for getting F1 force
F+F1sin( )-F1sin( ) = 0
F1=3263N
Maximum Force Acting on Jaw
PA=210mm
PB=140mm
Taking moment about p
Mp=0
0 = (F1xPB)-(PAxF2xcos(90- ))
F2 = 1609.344N~1610N

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6.2 Bolt Design

Material : Medium carbon steel
Yield stress yt =3600 psi
= 248.21 N / mm2
Assuming factor of safety = 3
Shear stress , =yt /2 FS
= 82.737/(2*3)
= 41.368 N / mm2
At hinge joint
Bolt diameter d = 20mm
Area A =

)/4

= ( 20

)/4

= 314.25mm2
Force acting on the bolt F= 2 A
= 41.368*2*314.25
=25992.59N
The maximum force acting on the bolt is 5000N.
Hence designing of bolt is safe.
Similarly the diameter of the bolt at pivot joint = 16mm
A=

)/4

= ( 16

)/4
=201.14mm2

Force acting on the bolt F= 2A

=41.368*2*201.14
=16633.85N

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The maximum force acting on the bolt is 5000N.

Hence designing of bolt is safe.

6.3 Link Design

Material: Mild steel
yt=248 N / mm2
= yt /2FS

Assume FS =3
= 248/(2*3)
= 41.33N/mm2
Maximum force acting on link F= *A
Breadth b=30mm
Thickness t=5mm
A = b*t
= 30*5
=150mm2
F = 41.33*150
= 6199.5N
So the link is safe
6.4.Compressive Spring
Maximum load possible
K = spring constant
G = spring material's shear modulus
d

= Diameter of spring wire = 5mm

D = mean diameter of spring = Douter- d = 43mm-5mm=38mm

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Lfree = Free length of spring=125mm

Solid length LSolid= nt * d= (8+2)*5 =50mm

(nt= na +2=8+2=10)

na = Number of active coils = 8 coils

E = elastic modulus = 2*10^5 n/mm2
= Poisson ratio = 0.3
G = E/ (2*(1+))= (2*10^5)/(2*(1+0.3))= 76923.07 N/mm2
K = G*d4 /8*D3 *na = ((76923.07)*(5)^4)/(8*38^3*8) =13.69N/mm
Fmax = k*(Lfree LSolid)= 13.69*(125-50) = 1026N
Maximum shear stress in the spring
W = Wahl correction factor
W= (4C-1/4C-4) + (0.615/C)=[4(7.6)-1)/(4(7.6)-4)]+(0.615/7.6) =1.19
C = spring index
C=D/d = 38/5=7.6m
Tmax= ((8*W*D)/(*d3 ))*Fmax=8*1.19*38*1026/(pi*5^3)=945N/mm2

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CHAPTER 7
BENEFITS AND PROBLEMS
7.1 Benefits
The hydraulic jaws has got a simple design so it is easy to repair. As it is
hydraulically operated it produces less noise. It is possible to shear apart metal
parts and also lift heavy materials using this hydraulic jaws. It produces no spark
while operation and is also eco friendly.
7.2 Problems
The fabricated hydraulic jaws is slightly heavy so it cannot be carried away
by an individual alone. Although it works in horizontal and vertical position ,it
doesnot work in all positions .I t can be used only for low load application.

CHAPTER 8
RESULT
A prototype of hydraulic jaw was fabricated and was tested for its
working.It was successfully able to lift heavy materials as well as shear apart

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metal parts.

Fig 8.1 Fabricated model

CHAPTER 9
CONCLUSION

Our project is a prototype working model of Hydraulic Jaws.

The model is completed and tested successfully. Our aim was to build a portable
hydraulic jaw which can be mechanically operated. On the basis of operation the
model is working perfectly, even though it is heavy. So by reducing its weight it

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could be actually used as a rescue tool to save victims trapped during accidents.

REFERENCES
1. Thomas A. Sullivan, James D. Van de Van , Multi-objective, multi-domain
genetic optimization of a hydraulic rescue spreader ,Department of
Mechanical Engineering , University of Minnesota, United States(2014)
2. "Hurst Rescue Tool". Motor Trend (Petersen Publishing Co.). 23 Number 9:
8283. September 1971.
3. NFPA Standard On Powered Rescue Tools, 2010 edition, Chap. (2010) 78
Quincy, MA

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4. A Textbook of Machine Design, R.S Khurmi & J K Gupta

5.

Structural Analysis ,Russell.C.Hibbler

6.

Design data - data book of engineers, P S G College of engineering

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HYDRAULIC JAWS

GROUP MEMBERS
ASWIN KUMAR
DIPSON K.P
JOBIN JOHNSON
LIBIN LAZAR
LIJO JOY

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GUIDE
SANDEEP.K