Engineers Gallery

Cotter and Knuckle Joints Understanding

Cotter and Knuckle Joints

Cotter and Knuckle Joints

Cotter and Knuckle Joints:

  1. Introduction : A cotter is a flat wedge shaped piece of rectangular cross-section and its width is tapered (either on one side or both sides) from one end to another for an easy adjustment. The taper varies from 1 in 48 to 1 in 24 and it may be increased up to 1 in 8, if a locking device is provided. The locking device may be a taper pin or a set screw used on the lower end of the cotter. The cotter is usually made of mild steel or wrought iron. A cotter joint is a temporary fastening and is used to connect rigidly two co-axial rods or bars which are subjected to axial tensile or compressive forces. It is usually used in connecting a piston rod to the cross head of a reciprocating steam engine, a piston rod and its extension as a tail or pump rod, strap end of connecting rod
    etc.
  2. Types of Cotter Joints : Following are the three commonly used cotter joints to connect two rods by a cotter :
    1. Socket and spigot cotter joint                                                      
    2. Sleeve and cotter joint, and                                                          3. Gib and cotter joint.

Reference A Textbook of a Machine Design by R.S. Khurmi and J.K. Gupta

Exit mobile version