DOUBLE ACTING HACKSAW USING SCOTCH YOKE
MECHANISM
CONTENTS
1. Introduction about the project
1.1 Introduction
1.2 Scotch yoke mechanism
1.3 Problem statement
2. Mechanism
2.1 Principle
2.2 Mathematical explanation
3. Description
4. Parameters
5. Construction of Scotch yoke mechanism
6. Result
7. Discussion
8. Industrial Purposes
9. Cost Estimation
10. Conclusion
11. Reference
1. Introduction of the project
1.1 Introduction
To satisfy the needs of the industries, we have designed a machine. The machine is exclusively
intended for the mass production and they represent fast and more effective way to cut the materials.
There are numerous types of cutting machines in engineering field, which are useful in fulfilling the
requirements. This new machine is used to avoid the energy loss and save time. Scotch yoke
mechanism is used for this purpose.
1.2 SCOTCH YOKE MECHANISM
The Scotch yoke mechanism is a reciprocating motion mechanism, converting the linear motion of a
slider into rotational motion, or vice versa. The piston or other reciprocating part is directly coupled to
a sliding yoke with a slot that engages a pin on the rotating part. In many internal combustion engines,
linear motion is converted into rotational motion by means of a crankshaft, a piston and a rod that
connects them. The Scotch yoke is considered to be a more efficient means of producing the rotational
motion as it spends more time at the high point of its rotation than a piston and it has fewer parts.
1.2 Problem Statement
Current scenario of industry focuses on the high production rate with less consumption of resources.
To achieve this we need to minimize idle time and machine time per unit. The multi-way power
hacksaw improves those factors by reducing time per unit to increase the production.
Problem Definition
To cut different metal bar pieces with high rate and accuracy to minimize an idle time.
Present method and problems associated
In present situation electrical as well as hydraulic operated machines are used but the output from
them is not satisfactory as it has low cutting rate.
2. Mechanism
2.1 Principle
This Mechanism is an inversion of Double Slider Crank Mechanism. The inversion is obtained by
fixing either the link 1 or link 3.In figure, link 1 is fixed. In this mechanism when the link 2 (which
corresponds to crank) rotates about B as center, the link 4(which corresponds to the frame)
reciprocates. The fixed link 1 guides the frame.
2.2 Mathematical Explanation
Suppose crankshaft is rotating at an angular velocity ‘w’. If ‘r’ is the radius of crank then,
Tangential velocity, V=rw
From the mechanism, I have the following relations- Component of tangential velocity in Y-direction
is given by, U=Reciprocating velocity of U-slot.
If ‘a’ is the angle made by the tangential velocity with X-axis at any point of time, Component of
tangential velocity in Y-direction is
U=rw sin (a) U=v sin (a)
So, Velocity of U-slot=V sin a
As a result, Velocity of U-slot is a function of sine function of a.
Now, as I know that is directly proportional to the time. This implies that the velocity of u-slot is a
sine function of a so the motion of U-slot is a simple harmonic motion.
3. Description
Double acting power hacksaw cuts two material simultaneously by its scotch yoke mechanism, so the
production rate increase twice then that of power hacksaw. Double acting power hacksaw works under
by the scotch yoke mechanism. The scotch yoke mechanism convert the rotary motion into the
reciprocating motion.
4. Parameter
1. Frame Work 2. Scotch Yoke Mechanism
Length: 68.5 cm Tube length: 85.5cm Slider height: 13cm
Breadth: 18.5 cm Tube diameter: 2.5cm Slider width: 5cm
Height:71 cm Disc: 14cm Rectangular frame length: 68.5cm
Rectangular frame height: 36cm
5. Construction of Scotch yoke mechanism
The scotch yoke mechanism is constructed with iron bars. Here the crank is made in some length and
the yoke is also made using the same material. It is noted that the minimum length of the yoke should
be double the length of the crank. The crank and yoke is connected with a pin. Iron bars are welded to
both sides of the yoke to get the reciprocating motion. The yoke with the iron bars is fixed on the
display board with the help of c clamp. Now the crank is welded to the end of the shaft of the motor.
Now the pin on the crank is connected to the yoke. The pin used to connect yoke and crank is a bolt
Fig: Velocity Diagram
6. Result
This project employs the Scotch yoke mechanism in power hacksaw machine which enables it to cut
two components at a time thereby improving the productivity. In today’s world time a machine should
be less time consuming. Power hacksaw cut one piece at one time so there was a loss in production
rate. Double acting power hacksaw overcome this time consuming problem. Power hacksaw is a fine
tooth power saw with blade held under tension in the frame.
7. Discussion
After studying this report, we have to know that how the A hacksaw machine will work and knowing
the construction and how mechanism work in the machine. We learnt how the theoretical design is
possible in practice. Another hacksaw machine is only cut one part at one time but this machine cut
the four parts at a time, this hacksaw machine has lighter weight compared to another machine. The
cost of the machine is less and easy to operate so it affordable for all industry. The material cast iron
which is used will give the high strength than alloy steels. This project is very much useful and easy
to install by the user and also the motor used will not only operate with the help of electricity but also
through conventional source of energy like solar energy.
8. Industrial Purposes
Advantages
The weight of the machine is less.
It reduces the work of labor.
Easy to make because of simpleconstruction.
High production rate.
Cost is less.
Easy maintenance and maintenancecost is less.
It resists all atmospheric effects.
Disadvantages
Time consume more.
Speed variation is required for cuttingthe different metal
Applications
In engineering industry.
In construction industry.
In Workshop.
9. Cost estimation
This cost estimation is an attempt to forecast the total expenses that may include to manufacture apart
from material cost. Cost estimation of manufactured parts can be considered as judgment on and after
careful consideration which includes lab our, material and factory services required to produce the
required.
Cost estimation is done as under:
Cost of project = Material cost + Machining cost + labor cost
10. Conclusion
As per the above discussion we concluded that to overcome problems in conventional hacksaw
machines, due to high efficiency, easy to operate and affordable price the proposed model of multi-
way power hacksaw machine is helpful and completes all the expectations needed in the mini
industries. Future scope of proposed research work to increase the production rate, cuts the metal bars
easily. It can withstand the vibrations, no hazards from jerk, no special training required to operate it.
11. Reference
[1]. Build a power hacksaw with vise, Authors: - Vincent Gingery
[2]. D.V. Sabarinanda, Siddhartha, B. Sushil Krishnana, T. Mohanraj , “Design and Fabrication Of
Automated Hacksaw Machine”, International Journal of Innovative Research in Science,Engineering
and Technology, ISSN (Online): 2319-8753, volume 3, April 2014.
[3]. R. Subhash, C.M. Meenakshi, K. Samuel Jayakaran, C. Venkateswaran, R. Sasidharan,
“Fabrication pedal powered hacksaw using dual
[4]. Prof. Nitinchandra R. Patel, Mohammad A. Vasanwala, Balkrushna B. Jani, Ravi Thakkar,
Miteshkumar D. Rathwa,”Material selection and testing of hacksaw blade based on mechanical
Properties”, International Journal of Innovative Research in Science, Engineering and Technology,
ISSN: 2319-8753, volume 2, Issue 6, June 2013.
