Abstract: Brake apparatus, particularly one in which the brake may be both actuated and released by a hydraulic force, held engaged by a mechanical force and in which a strong spring force, tending to restore the brake, prevails while the brake is held engaged; brake applying pressure, after the brake is engaged, is at first slowly released, hydraulic pressure employed to release the brake is maintained at a minimum value even though the brake may be released and certain conditions are sensed for coincidence before generating a signal indicating that the brake release conditions are complied with.

Abstract: A new and improved ram lock for blowout preventer rams which permits locking of the ram at multiple and adjustable positions to compensate for wear on sealing elements of blowout preventer rams and increase sealing action of the ram without requiring separate special control lines. Automatic locking of the ram at a desired position, such as in adjustable sealing positions to compensate for ram elastomer wear, is obtained.

Abstract: A new and improved ram lock for blowout preventer rams which permits locking of the ram at multiple and adjustable positions to compensate for wear on sealing elements of blowout preventer rams and increase sealing action of the ram without requiring separate special control lines. Automatic locking of the ram at a desired position, such as in sealing position, is obtained.

Abstract: An actuator for a spring brake used for parking and emergency has a spring operating on the brake push rod which will apply braking unless fluid pressure in the braking system applied to a piston overcomes spring pressure. To disable the spring brake the rod is retracted by a mechanism coupling the piston to the rod so that the brake is automatically restored into service when the piston is operated by the fluid pressure. The mechanism has a one-way clutch engaging a threaded push rod by means of a nut in non-self-locking engagement on the push rod threads.

Abstract: A hydraulic hand brake for a fluid pressure actuated brake on a railway vehicle has a cylinder and piston assembly extending coaxially from the brake cylinder. A threaded rod having a non-locking thread extends from the piston and has threaded thereon a traveling nut with a coupling surface on a side away from the brake piston engageable with a second coupling surface on a ring attached to the cylinder. A spring urges the nut in the direction to engage the coupling surfaces and a control piston engages the nut to disengage the coupling surfaces when the control piston is subjected to a hydraulic pressure. Subjecting the piston of the cylinder and piston assembly to a hydraulic pressure will cause the threaded rod to engage the brake piston and to move the brake piston in the braking direction.

Abstract: A disc or drum brake fluid pressure actuator incorporates a lock actuator strut acting on an inner part of a telescopic piston assembly, of which the inner and outer parts are normally rendered effectively unitary by pre-stressed spring which can, however, deflect under excess pressure to permit extension of the lock actuator strut when it is desired to operate the strut for parking purposes. An hydraulic control system for operating the actuator is also described and illustrated.

Abstract: A fluid cylinder having a tubular housing with a piston reciprocably mounted therein and capable of fluid pressure actuation in opposite directions. One side of the piston carries an actuating rod which slidably extends through one end of the tubular housing, while a coaxially aligned bore extending from the opposite side of the piston and into the actuating rod has a threaded surface adapted to receive a threaded member which, in turn, is rotatably carried at the other end of the tubular housing. The threaded surfaces of the piston bore and the rotatable threaded member engage in a self-locking relationship such that the piston is incapable of movement when subjected to fluid pressure unless the threaded member is initially and continually rotated. Means are provided for selectively rotating the threaded member upon fluid pressure actuation of the piston in either direction.