The most commonly used types of cotter joints are; i Cotter joint with Socket and spigot end fig. A cotter is driven tightly through the slots in the rods which are kept slightly mis aligned. The cotter comes in contact with the two rods on opposite sides and leaves clearances on both sides.
Clearances are absolutely required for proper functioning of the joint. The ends of the two rods are inserted from opposite sides in a cylindrical sleeve or steel box. Two cotters are inserted through the slots on each rod end. The slots in the rods and sleeve are made slightly wider than the width of cotter. Pin-Joint or Knuckle Joint:.
The joint is used for rods whose axes intersect i. It is employed in tension or compression. The joint permits angular movement between the rods there fore it is not rigid. Although a cotter joint will resist the rotations of one rod relative to the other, it should not be used to join a rotating shaft.
To prevent this, the gib is used that holds the ends of the strap together. In addition, the gator provides a larger bearing surface for the cotter to slide as the holding power increases. Thus, the friction of the cotter reduces the tendency to slacken back. Gib also enables parallel holes to be used. Gib and cotter joints are used for square or rectangular cross-section rods. The end of one rod fits into the end of the other rod, which is designed as a strap.
Answer: Design of Knuckle joint Failure of rod in tension Q 2 a 8 Question: Explain with the help of neat sketches three basic types of lever. State one application of each type. Answer: In the first type of levers, the fulcrum is in between the load and effort. Answer: Applications of cotter joint: cotter foundation bolt, big end of the connecting rod of a steam engine, joining piston rod with cross head, joining two rods with a pipe Applications of knuckle joint: link of bicycle chain, tie bar of roof truss, link of suspension bridge, valve mechanism, fulcrum of lever, joint for rail shifting mechanism Q 3 b 4 Question: Design single cotter joint to transmit kN.
Allowable stresses for the material are 75 MPa in tension and 50 MPa in shear. Answer: Our Sister Sites www. Q 1a ii. Question: What is a cotter joint? Question: Design a knuckle joint to transmit KN. Question: Why are bushes of softer material inserted in the eyes of levers? Question: Design a foot brake lever from the following data: Length of lever from C. Question: Give two applications of knuckle joint. Question: Explain various failures to be considered in designing a cotter joint along with the necessary sketches and strength equations.
Question: Fig. Question: Write the design procedure for turn buckle. Any four steps Answer: Write any four equation s in the design of turn buckle with relevant sketches Q 2a ii. Question: Why taper is provided on cotter? The normal value of taper varies from 1 in 48 to 01 in 24 and it may increase to 1 in 8 Question: Draw neat sketch showing the details of cotter joint.
Each rod is subjected to a tensile force P. Tensile Failure of Spigot :. Tensile Failure of Socket :. Shear Failure of Spigot End :. The spigot end is subjected to double shear.
Shear Failure of Socket End :. The socket end is subjected to double shear. Crushing Failure of Spigot End :. Crushing Failure of Socket End :. Crushing Stress,. Shear Failure of Spigot Collar :. Crushing Failure of Spigot Collar :. Shear Failure of Cotter :.
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