Wednesday, August 18, 2010

Dimensional Details of COTTER AND SLEEVE JOINT


This type of cotter joint is used for connecting two rods which are subjected to axial forces. The ends of the two rods are enlarged in diameter to reduce the effect of reduction in the strength of the rods due to cutting of the slots. The enlarged ends of the rods are introduced from the opposite sides into a cylindrical sleeve to butt against each other at the mid length of the sleeve length. The slots in the rods and as well as in the sleeve are made slightly larger than. The slots in the two rods are so located with respect to the slots in the sleeve such that when assembled, there will be an offset by a small amount, called clearance, between them. This intentionally provided offset requires driving of the cotter into the slots by applying the force. As the cotter is driven, its straight side is forced against the straight faces of the slots in the sleeve, while its tapered side is forced against the tapered faces in the slots in the rods which results in the pulling of the two rods as to hold them rigidly by the friction grip. This assembly leaves clearance in the sleeve and the rods. The provision of these clearances facilitates the axial adjustments of the two connecting rods.

The dimensional details for Cotter Joint with Sleeve will be shown in the next post.

Tuesday, August 17, 2010

Cotter and Pin Joints

Rods of circular and rectangular cross section subjected to axial tensile or compressive forces, are connected together by a cotter joint. It is a temporary method of fastening of the two rods which have to be frequently assembled and disassembled. Its chief advantages are that the joint can be quickly assembled and disassembled and rods occupy exactly the same relative positions after assembly. The cotter joints are used to connect the piston rod, to the same cross head of the steam engine, pump or compressor. Long tie bars in steel structures are some, times built up of round bar, of short lengths and jointed together by cotter joints.

Monday, August 16, 2010


On the cylindrical surface of the nut, number of slots parallel to the axis is cut. The nut is operated by a C-Spanner. These are used in large screws for small pitches where adjustment by a spanner is convenient. The empirical proportions are based on the nominal diameter of the bolt.


This type of nut is used where frequent turning on or off the nut is desired. This nut is operated by the thumb and a finger.


It is cylindrical in shape. Six holes are drilled in the curved surface of the nut for turning it with a Tommy bar introduced in these holes. Sometimes holes are also drilled in the upper flat face of the nut, for turning with a Tommy bar.


The nut is used when finger tightness and quick turning on or off is desired as in the case of terminals of electrical apparatus.

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