Manufacturing method of COTTER

joint

By – JADHAV AKSHAY(TM114) JADHAV AMIT (TM115) JADHAV AJAY (TM113)

COTTER JOINTA cotter joints is a flat wedge link piece of steel of

rectangular cross section which is inserted through the rods at high angle to their axes .It is uniform in thickness but tapering in width , generally on one side only. Usually the taper is 1 in 30. when a special arrangement like a set-screw is provided for keeping the cotter from slackening ,its taper may be as large as 1 in 7. the end of the cotter are made narrow to facilitate the hammering for fixing and removing.

cotter joins are generally use to fasten rigidly two rod s which is subjected to tensile or compressive stress along their axes. this joint is used to connect two circular rods.

This joint in not suitable where the member are subjected under rotation.

Thus they differ from key joints which are used to fasten shaft and hubs subjected to tensional stress:

The Cotter joint assembly consist of following major components: 1.Socket. 2. Spigot 3.cotter

The construction of a cotter joint used to connect two rods .consider rod A & B . Rod A is provided with a socket end whereas rod B is provided with a spigot end and inserted into a socket .

The socket and spigot is provided with a narrow rectangular slot with taper on one side and a cotter is tightly fits into the slots .

A cotter is wedge-shaped piece made of a steel plate having rectangular c/s with its width tapered on one side to match the taper in slots provided in socket and spigot .

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Exploded view of Cotter joint

Mainly cotter joint is manufacture by using deformation process

a metal is either hot or cold, is plastically deform into the

desire shape. Forging , rolling, extrusion, press working are the examples of deformation process

All parts of cotter joint are manufacture by forging process

In forging metal is in plastic stage, rather than in the molten stage is force to flow in the desired shape

Further cotter joint is manufactured by cold forging

Application:1.Joint the piston rod and the crosshead of

steam engine2.to joint spindle and fork of the valve

mechanism.3.to joint piston rod and tail of pump rod.Foundation bolts.

Why forging process is useThe fiber lines of a forged components can be arranged in a

predetermined way to suit the direction of external forces that will act on the component when in service

Therefore forged components have inherent strength & they are ideally suitable for applications like connecting rods and crankshafts

Forged components can be provided with thin section without reducing the strength . This result in lightweight construction

Forging the cotter as a separate part provides greater flexibility in the selection of forging techniques and also provides a smaller part for the machining and boring operations

Actual forging process

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