Cotter and Knuckle Joints:
- 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
- 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.
The design of these types of joints are discussed, in detail, in the following pages.
- Socket and Spigot Cotter Joint
- Design of Socket and Spigot Cotter Joint
- Sleeve and Cotter Joint
- Design of Sleeve and Cotter Joint
- Gib and Cotter Joint
- Design of Gib and Cotter Joint for Strap End of a Connecting Rod
- Design of Gib and Cotter Joint for Square Rods
- Design of Cotter Joint to Connect Piston Rod and Cross head
- Design of Cotter Foundation Bolt
- Knuckle Joint
- Dimensions of Various Parts of the Knuckle Joint
- Methods of Failure of Knuckle Joint
- Design Procedure of Knuckle Joint
- Adjustable Screwed Joint for Round Rods (Turn Buckle).
- Design of Turn Buckle.
Reference A Textbook of a Machine Design by R.S. Khurmi and J.K. Gupta