Hydraulic brake actuating and locking device

Claim 1

A hydraulic brake actuating and locking device for applying brakes of a vehicle comprising an elongated brake cylinder having a tubular push rod axially operable therein for actuating the brakes and a hydraulically controlled locking means for selectively locking axial movement of the push rod relative to the brake cylinder wherein improved locking and control means comprises; a. a brake cylinder secured between a pressure end flange at one end and a push rod bearing end flange at the other end, b. an annular locking device disposed within the tubular push rod and operable when rendered effective for acting on a uniform smooth inner periphery of the push rod to restrain the push rod against axial movement relative to the brake cylinder, irrespective of the extent to which the push rod is contained within the brake cylinder, the annular locking device comprising; 1. a fixed locking rod coaxial within the push rod having a plurality of wedges disposed about the periphery thereof at one end and having its other end secured within the pressure end flange, 2. an axially operable tubular locking rod slideable on the fixed locking rod within the push rod and carrying rollers at one end thereof adapted to be wedged between the respective wedges of the first locking rod and the inner periphery of the tubular push rod for use in locking the push rod to the fixed lock rod for preventing retraction of the push rod within the cylinder, and 3. a piston secured on the axially operable locking rod at its other end and disposed in a pressure compartment within the pressure flange whereby the locking of the push rod can be rendered selectively effective or ineffective in accordance with the application of fluid pressure at one side or the other respectively of the locking piston in the pressure chamber.