Table of Contents

Double Acting Hacksaw Using Scotch Yoke Mechanism Report

ABSTRACT

Increasing the productivity is one of the main requirements of production engineering in any kind of manufacturing industry. Either by reducing the operation time or by improving the capability of the machine to produce the components in an increased number at the same time is very essential for an industry to achieve the same. 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. 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.

INTRODUCTION

In this project, we have designed a double acting hacksaw machine. In industries saving the time and saving the manpower is an important thing all over the world.
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.

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.

CONSTRUCTION

Machine has the prime mover at the bottom of the machine. The pulley is attached to the body at the top and end of the side portion. Pulley is connected with disc type plate. The pulley and disc has separate connection with one small metal rod through the bearings.

Double acting hacksaw machine using scotch yoke Mechanism report Download

Motor and pulley is connected with one V type belt. The clamp is fixed with the disc and at the end of two shafts. Hack saw connected to the each shaft at the end.
Construction of double acting hacksaw using scotch yoke mechanism consist the following components.
1. DC Motor
2. Pulleys
3. Bearings
4. Shaft
5. Hack saw
6. V belt

PARTS REQUIRED

Following parts are needed for construction of the construction of Double acting hacksaw using scotch yoke mechanism.

1. D.C. Motor
2. Aluminum strips with holes
3. Power supply
4. Square tubes
5. Hacksaw
6. Nut-bolts
7. Switches
8. Plywood
9. Slots and guides
10. Pulley and belts
11. Miscellaneous

ADVANTAGE:

High torque output with a small cylinder size.
Fewer moving parts.
Smoother operation
Higher percentage of the time spent at top dead centre (dwell) improving theoretical engine efficiency of constant volume combustion cycle though actual gains have not been demonstrated.
In an engine application, elimination of joints typically served by a wrist pin, and near elimination of piston skirt and cylinder scuffing, as side loading of piston due to sine of connecting rod angle is eliminated.

DISADVANTAGE:

Rapid wear of the slot in the yoke caused by sliding friction and high contact pressure.
Increased heat loss during combustion due to extended dwell at top dead center offsets any constant volume combustion improvements in real engines.

APPLICATION:

This setup is most commonly used in control valve actuators in high pressure oil and gas pipelines.
It has been used in various internal combustion engines, such as the Bourke engine, Sytech engine and many hot air engines and steam engines.
It is also used in multipurpose machine and I.C. engines.