Shih Zen Sheng

44717970, Sep 18, 1984

Mar 19, 1982

6/359957

Ronald F. Cass - Yorba Linda CA
Shih Y. Sheng - Santa Ana CA

Parker-Hannifin Corporation - Cleveland OH

F15B 1108

137100

A hydraulic system includes a pump, a reservoir, and an actuator system. A hydraulic circuit breaker is arranged to compare fluid flow to and from the actuator system and to shut off this flow in the event the flow to the actuator system is greater than the flow returning from the actuator system by more than a predetermined differential, thereby indicating a leakage condition. A hydraulic circuit breaker reset device is hydraulically connected to the actuator system and to the circuit breaker. When the circuit breaker is in a shut-off condition, the reset device continuously pressure tests the actuator system. If the pressure in the actuator system increases to indicate the absence of fluid leakage, the reset device responds to the pressure increase in the actuator system to provide a reset signal to the circuit breaker. After the circuit breaker is reset to its normal operating position, a timing piston returns the reset device to its normal operating condition.

45256950, Jun 25, 1985

Apr 4, 1984

6/596489

Shih Y. Sheng - Santa Ana CA
Ray A. York - Villa Park CA

Parker Hannifin Corporation - Cleveland OH

H01F 708

335262

A direct drive valve wherein a force motor (10) controls the position of a valve slide (20) through a linkage (14). The force motor includes a spring assembly (62) having cantilevered springs (68 and 70) that include petals (72). The armature (48) of the force motor is guided by a plurality of balls (84) that contact both an internal tube assembly (47) and the armature.