Cotter (pin)
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A cotter is a pin or wedge passing through a hole to fix parts tightly together. In British usage cotter pin has the same meaning,[1] but in the U.S. it means a split pin.
Typical applications are in fixing a crank to its crankshaft, as in a bicycle, and a piston rod to a crosshead, as in a steam engine. The angle of the wedge determines the position of the parts being held; therefore, on a bicycle, the pedal arms will only be at 180 degrees to each other if the angle of the cotter pin's wedge is the same on both pins.
Popular usage
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Formerly, it was common to mount bicycle cranks using a cotter, although now a more easily maintained arrangement is typically used, such as a square tapered or splined interface. These cotters have a short threaded section at the narrower end of the taper, which is used to hold the cotter in place with a washer and nut. They are also used to secure ceiling fans to prevent falling if the mounting nut loosens.
See also
[edit]- Bottom bracket – Bicycle component
- Crankset – Bicycle part
- Mechanical joint – Section of a machine which is used to connect one mechanical part to another
- Split pin – Metal fastener with two tines that are bent during installation
- Taper pin – Fastener consisting of a steep conical rod which is forced into a hole
References
[edit]- ^ Van der Plas, Rob (1993), The Bicycle Repair Book: The New Complete Manual of Bicycle Care (2nd ed.), MBI Publishing Company, p. 66, ISBN 978-0-933201-55-2[permanent dead link].
External links
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Media related to Split cotter pins at Wikimedia Commons
