23-09-2014, 11:28 AM
DESIGN AND FABRICATION OF PEDAL POWERED HACKSAW
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ABSTRACT
This project deals with the design and fabrication of pedal powered
hacksaw setup .The aim of our project work is to develop a modernized
operation for cutting wood and plastic materials.
It is very useful for cutting PVC materials. It can be used widely in
lathe and in furniture making industries.
Since the manual effort by cutting through pedaling a wheel is
much lower than cutting by hand. Hence this project is very useful in our
day to day life.
INTRODUCTION
The pedal powered hacksaw set up, has a simple mechanism
operate with chain and sprocket gear arrangement. As by pedaling the
wheel rotary motion is converted into the To and Fro motion of the
cutting tool (hacksaw). It takes very simple. The rotary motion is
converted in to linear motion by crank and pinion arrangement.
The size and shape of this setup is similar to cycle. It is like a cycle
is added with a bed for cutting a work piece. As it required very low
pedaling power it can be operated by very low power. Chain mechanism
is used thus it transmit power without much of loss. Lubrication of chain
and crank arrangement is made by grease and oil. Bearing is used for the
smooth transmission of rotary motion in to the rake and pinion
arrangement.
NEED FOR AUTOMATION
Automation is the use of control systems (such as numerical control,
programmable logic control, and other industrial control systems), in concert with
other applications of information technology (such as computer-aided technologies
[CAD, CAM, CAx]), to control industrial machinery and processes, reducing the
need for human intervention. In the scope of industrialization, automation is a step
beyond mechanization. Whereas mechanization provided human operators with
machinery to assist them with the muscular requirements of work, automation
greatly reduces the need for human sensory and mental requirements as well.
Processes and systems can also be automated.
Automation plays an increasingly important role in the world economy and
in daily experience. Engineers strive to combine automated devices with
mathematical and organizational tools to create complex systems for a rapidly
expanding range of applications and human activities.
COMPONENTS
BEARING
A bearing is a machine element that constrains relative motion
between moving parts to only the desired motion.
The design of the bearing may, for example, provide for free linear
movement of the moving part or for free rotation around a fixed axis; or,
it may prevent a motion by controlling the vectors of normal forces that
bear on the moving parts.
Bearings are classified broadly according to the type of operation, the
motions allowed, or to the directions of the loads (forces) applied to the
parts
TYPES OF BEARINGS
There are numerous different kinds of bearings that are designed to
handle radial load, thrust load, or some combination of the two. Because different applications require bearings that are designed to handle a
specific kind of load and different amounts of weight, the differences
between types of bearings concern load type and ability to handle
weight.
ROLLER BEARING
Roller bearings are designed to carry heavy loads the primary
roller is a cylinder, which means the load is distributed over a larger
area, enabling the bearing to handle larger amounts of weight.
This structure, however, means the bearing can handle primarily
radial loads, but is not suited to thrust loads. For applications where
space is an issue, a needle bearing can be used.
Needle bearings work with small diameter cylinders, so they are easier
to fit in smaller applications.
CONSTRUCTION OF CHAIN
There are actually two types of links alternating in the bush roller
chain. The first type is inner links, having two inner plates held together
by two sleeves or bushings upon which rotate two rollers.
Inner links alternate with the second type, the outer links,
consisting of two outer plates held together by pins passing through the
bushings of the inner links.
The "bushingless" roller chain is similar in operation though not in
construction; instead of separate bushings or sleeves holding the inner
plates together, the plate has a tube stamped into it protruding from the
hole which serves the same purpose.
This has the advantage of removing one step in assembly of the
chain.
The roller chain design reduces friction compared to simpler
designs, resulting in higher efficiency and less wear.
TRANSPORTATION
In the case of bicycle chains, it is possible to modify the
overall gear ratio of the chain drive by varying the diameter (and
therefore, the tooth count) of the sprockets on each side of the chain.
This is the basis of derailleur gears. A 10-speed bicycle, by
providing two different-sized driving sprockets and five different-sized
driven sprockets, allows up to ten different gear ratios.
The resulting lower gear ratios make the bike easier to pedal up
hills while the higher gear ratios make the bike faster to pedal on flat
roads.
In a similar way, manually changing the sprockets on a
motorcycle can change the characteristics of acceleration and
top speed by modifying the final drive gear ratio
HACKSAW
A hacksaw is a fine-tooth hand saw with a blade held
under tension in a frame, used for cutting materials such
as metal or plastics. Hand-held hacksaws consist of a metal arch with a
handle, usually a pistol grip, with pins for attaching a narrow disposable
blade.
A screw or other mechanism is used to put the thin blade under
tension. The blade can be mounted with the teeth facing toward or away
from the handle, resulting in cutting action on either the push or pull
stroke.
On the push stroke, the arch will flex slightly, decreasing the
tension on the blade, often resulting in an increased tendency of the
blade to buckle and crack. Cutting on the pull stroke increases the blade
tension and will result in greater control of the cut and longer blade life.
CONCLUSION
Thus this project work might be useful in all industries. For practical
applications this is fabricated for light duty operation. Its height, weight and other
mechanical designs are may be not suitable for any other heavy operation or work
on hardened material.
We are proud that we have completed the work with the limited time
successfully. The PEDAL POWERED HACKSAW works with satisfactory
conditions. We are able to understand the difficulties in maintaining the tolerances
and also quality. We have done to our ability and skill making maximum use of
available facilities.
In conclusion remarks of our project work, let us add a few more lines about
our impression on project work. Thus we have developed a “PEDAL POWERED
HACKSAW ” which helps to know how to achieve simple cycling mechanism.
The application of this machine is comparatively wide with respect to the cost of
the machine.