camming device
noun
1 Mechanics a component that involves a camming action.
2 Mountaineering and Rock Climbing any of various devices inserted into a rock fissure for protection when climbing, in which downwards force exerted on one or more cams causes the device to grip the rock; specifically a device of this type consisting of several spring-loaded cams mounted on an axle or axles.
Origin
Early 20th century; earliest use found in U.S. Patents.