Cotter Joint & Knuckle

joint

Presented By:- SHUBHAM ANAND mechanical engg. dept

Cotter Joint

What Is A Cotter Joint?• Cotter joints are the joints made with the help of cotter.• Cotter joint is a flat wedge shaped piece of steel.

• cotter is used to connect rigidly two rods which transmit motion in the axial direction, without rotation.

• These joints may be subjected to tensile or compressive forces along the axes of the rods.

• Examples of cotter joint connections are: connection of piston rod to the crosshead of a steam engine, valve rod and its stem etc.

Cotter joint contains has mainly three components

1. Socket2. Spigot3. cotter

• In cotter joint there are two pipes having connection with the help of cotter.

• One of the rods has a socket end into which the other rod is inserted.

• the cotter is driven into a slot, made in both the socket and the rod. The cotter tapers in width (usually 1:24)* on one side of it.

*Reference: design of machine elements by V B bhandari, Tata Mc Graw Hill edu.

APPLICATION OF COTTER JOINT

Advantages of cotter joint

• Simple to design and manufacture

• Simple to assemble and dismantle

• Very high tightening force due to wedge action which prevents loosening of parts in service

Applications of cotter joint

• Joint between the piston rod and the cross head of a steam engine.

• Joint between the slide spindle and the fork of valve mechanism.

• Joint between the piston rod and the tail and pump rod

• Foundation bolt

Knuckle Joint

What is a knuckle joint?• The knuckle joint is used to connect two rods under tensile

load.• This joint permits angular misalignment of the rods and may

take compressive load if it is guided.

Components of Knuckle joint

• Eye• Fork• Pin

• These joints are used for different types of connections e.g. tie rods, tension links in bridge structure. In this, one of the rods has an eye at the rod end.

• The other one is forked with eyes at both the legs. A pin (knuckle pin) is inserted through the rod-end eye and fork-end eyes and is secured by a collar and a split pin.

APPLICATION OF KNUCKLE JOINT

Advantages of knuckle joint

• simple to design and manufacture

• fewer parts -less cost more realibility

• simple to assemble and dismantle

Application of knuckle joint

• Joints between the tie bars in a roof trusses.• Between the links of suspension bridge.• In valve mechanism of a reciprocating engine.• Fulcrum for the levers.• Joints between the links of a bicycle chain.

Thank you