Lockable ball joint apparatus

摘要

A lockable ball joint apparatus including a ball and a ball receiving cavity and at least one annular clamp ring in the casing extending around the ball. The clamp ring has a spherically concave inner clamping surface engaging the outer surface of the ball and a frusto-conical outer surface. An annular cam extends around the clamp ring and has a frusto-conical inner surface engaging the frusto-conical outer surface of the clamp ring. The annular cam is formed on an annular piston and springs are provided for moving the annular piston and cam axially in a first direction to diametrically compress the clamp ring into clamping engagement with the ball, and fluid pressure is applied to the annular piston for moving the annular cam means axially in a second direction to release the clamp ring from clamping engagement with the ball.