Abstract: A hydraulic cartridge valve includes a movable member and a position monitoring mechanism configured to detect the position of the movable member. The position monitoring mechanism is adapted to generate a position signal indicative of the position of the movable member. The position monitoring mechanism can be in the form of a linear variable differential transformer (LVDT).

Abstract: A hydraulic actuator system includes a load sense assembly that is configured to transmit a load sense signal to a variable pump to vary a flow of pressurized fluid from the variable pump in response to the load sense signal to generate a desired flow to the actuator. The load sense assembly includes a load sense boost valve (LSBV) configured to dynamically boost the load-sense signal according to the desired margin pressure and the flow demand from the system. When flow demands are low, margin pressure will be above the set threshold of the adjustable LSBV, and no boosting occurs. When flow demands are high and pressure in the load sense line drops to the set threshold, or minimum margin pressure, the LSBV begins boosting the load sense signal pressure dynamically. The boosted load sense signal signals the variable pump to stroke and displace more fluid to increase flow to the actuator.

Abstract: A hydraulic motor drive system controls the pressure of the hydraulic fluid delivered to a motor by a variable pressure source to control the rotation of a high inertial load rotary member driven by the motor. The speed of the motor and/or rotary component is monitored and changes in the speed are controlled by changing the pressure of the hydraulic fluid delivered to the motor.

Abstract: A hydraulic motor drive system controls the pressure of the hydraulic fluid delivered to a motor by a variable pressure source to control the rotation of a high inertial load rotary member driven by the motor. The speed of the motor and/or rotary component is monitored and changes in the speed are controlled by changing the pressure of the hydraulic fluid delivered to the motor.

Abstract: A data disk storage system utilizing a bipolar stepper motor for use in conjunction with the controlling of the operation of the storage system. The stepper motor imparts a drive force for moving a control arm to which a read/write head is coupled. The operation of the stepper motor through driving of the control arm causes the read/write head to move across the various tracks of the data disk within the data storage system during operation of such system. The stepper motor includes a stator and a rotor coupled to an output shaft of the motor which output shaft in turn is coupled to the read/write head through the control arm. A first drive mechanism within the stepper motor generates a first phase signal within the stator for creating a first drive force for rotating a rotor. A second drive mechanism of the stepper motor generates a second phase signal within the stator for creating a second drive force for rotating the rotor.