CBSE Class 12 Engineering Rod Joints

ROD JOINTS

All of you have seen a tractor and its trolley/ trailer. The trolley can be easily joined or removed from the tractor as per the need. Have you ever noticed that how this trolley is joined or detached from the tractor? This work is made so simple by a joint between the tractor and the trolley using a pin or a cotter. A fork end is there at the back of the tractor and an eye end is there in front of the trolley and a round rod is inserted in between these two to make the joint. In industry also different cotter joints are used some of these we shall learn in the following paragraphs. First of all we shall learn about the cotter.

COTTER
A cotter is a flat rectangular cross section wedge-shaped piece or bar of mild steel block which is uniform in thickness but tapering in width on one side in general. It is used to connect rigidly two rods, whose axes are collinear and which transmit motion in the axial direction (tensile or compressive forces) without rotation. The cotter is inserted perpendicular to the axes of the shafts which are subjected to tensile forces. Cotter provides rigid joint support. 

Exercises

Q.1. What is cotter?

Q.2. What are dimensions of a cotter in terms of the diameter of the shafts to be joined?

Q.3. Why clearance is necessary in a cotter joint?

Q.4. What do you understand by the self locking of the cotter?

Q.5. Why a Gib is used along with a cotter in a Gib and cotter joint?

Q.6. Where knuckle joint is used?

Please refer to the link below for - CBSE Class 12 Engineering Rod Joints