KEYS
• Used to prevent the rotation of pulleys, gears, etc., on their shafts.
• A key is a piece of metal placed so that part of it lies in a groove, called the ‘key seat’, cut
in a shaft. The key than extends above the shaft and fits into a ‘keyway’ cut in a hub.
• After assembly, the key is partly in the shaft and partly in the hub, locking the two together
so that one cannot rotate without the other.
KEY TYPES
• Square Key
Placed half in the shaft and half in the hub. Square in cross-section
• Flat Key
Rectangular in cross-section and used in the same manner as square key
• Woodruff Key
• Flat segmental disk with a flat or round bottom
• The key seat is semicylindrical and cut to a depth so that half the width of the key
extends above the shaft and into the hub.
KEY TYPES
• Square Key
Placed half in the shaft and half in the hub. Square in cross-section
• Flat Key
Rectangular in cross-section and used in the same manner as square key
• Gib-head key
Tapered on its upper surface and is driven in to form a very secure fastening.
• Woodruff Key
• Flat segmental disk with a flat or round bottom
• The key seat is semicylindrical and cut to a depth so that half the width of the key
extends above the shaft and into the hub.
COTTERS
• Flat wedge-like pieces of steel used to fasten rods, etc., together when such rods are
subjected to axial forces only.
COTTERED JOINTS
COTTERED JOINTS
