Cotter and Knuckle Joints:
- Introduction :Ā A cotter is a flat wedge shaped piece of rectangularĀ cross-section and its width is tapered (either on one side orĀ both sides) from one end to another for an easy adjustment.Ā The taper varies from 1 in 48 to 1 in 24 and it may beĀ increased up to 1 in 8, if a locking device is provided. TheĀ locking device may be a taper pin or a set screw used on theĀ lower end of the cotter. The cotter is usually made of mildĀ steel or wrought iron. A cotter joint is a temporary fasteningĀ and is used to connect rigidly two co-axial rods or barsĀ which are subjected to axial tensile or compressive forces.Ā It is usually used in connecting a piston rod to the cross headĀ of a reciprocating steam engine, a piston rod and itsĀ extension as a tail or pump rod, strap end of connecting rod
etc. - Types of Cotter Joints :Ā Following are the three commonly used cotter joints to connect two rods by a cotter :
1. Socket and spigot cotter joint Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā 2. Sleeve and cotter joint, and Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā 3. Gib and cotter joint.
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The design of these types of joints are discussed, in detail, in the following pages.
- Socket and Spigot Cotter Joint
- Design of Socket andĀ Spigot Cotter Joint
- Sleeve and Cotter Joint
- Design of Sleeve andĀ Cotter Joint
- Gib and Cotter Joint
- A Design of Gib and CotterĀ Joint for Strap End of aĀ Connecting Rod
- Design of Gib and CotterĀ Joint for Square Rods
- A Design of Cotter Joint toĀ Connect Piston Rod andĀ Cross head
- Design of CotterĀ Foundation Bolt
- Knuckle Joint
- Dimensions of Various PartsĀ of the Knuckle Joint
- Methods of Failure ofĀ Knuckle Joint
- Design Procedure ofĀ Knuckle Joint
- Adjustable Screwed JointĀ for Round Rods (TurnĀ Buckle).
- Design of Turn Buckle.
Reference A Textbook of a Machine Design by R.S. Khurmi and J.K. Gupta