Abstract: A rod clamp device having a rod clamp sleeve with a frusto-conical outer surface and an annular cam with a frusto-conical inner surface and an annular ball guide cage arranged to equalize movement of the bearing balls in circumferentially spaced paths along the clamp sleeve so that the annular cam applies pressure through the bearing balls uniformly around the rod clamp sleeve when the cam is moved axially in one direction to a rod clamp position, and the annular cam uniformly releases pressure on the bearing balls when the cam is moved axially in an opposite direction to a release position. The rod clamp sleeve has slots and the ball guide cage is keyed to the clamp sleeve to maintain a preset angular relation therebetween while allowing relative axial movement.

Abstract: A fluid pressure operated braking device for a piston rod. The braking device includes a clamp sleeve and a cam member spring biased axially in a direction to actuate the clamp sleeve to a clamp condition, and a fluid pressure operator that provides a hydraulically amplified force for moving the cam member in opposition to the spring to release the clamp sleeve. The fluid pressure operator includes a first piston operated in response to fluid pressure applied thereto to produce a force correlative with fluid pressure and the first piston is connected to a second piston that pressurizes a non-compressible fluid in a closed pressure chamber communicating with a third piston, and a third piston actuates the cam ring in opposition to the spring to release the clamp ring.