Abstract: A control system is provided for a hydraulic actuating system having a multi-phase stepping motor with a driver therefor which supplies and controls DC current through each of the motor windings such that no current is induced into the control winding from adjacent windings. The stepping motor precisely controls the rotation of an eccentric cam engaging an actuating plunger which actuates a control valve of the hydraulic actuating system. The driver receives control signals from a computer programmed to calculate, from user input command signals indicative of the desired system condition, and generate those control signals which most quickly achieve a rough approximation of the desired system condition. After this rough approximation is attained, the computer generates new control signals for the driver as a function of feedback signals and/or system component characteristics so as to precisely achieve the desired system condition.

Abstract: A control system is provided for a hydraulic actuating system having a multi-phase stepping motor with a driver therefor which supplies and controls DC current through each of the motor windings such that no current is induced into the control winding from adjacent windings. The stepping motor precisely controls the rotation of an eccentric cam engaging an actuating plunger which actuates a control valve of the hydraulic actuating system. The driver receives control signals from a computer programmed to calculate, from user input command signals indicative of the desired system condition, and generate those control signals which most quickly achieve a rough approximation of the desired system condition. After this rough approximation is attained, the computer generates new control signals for the driver as a function of feedback signals and/or system component characteristics so as to precisely achieve the desired system condition.

Abstract: A control system is provided for a hydraulic actuating system having a multi-phase stepping motor with a driver therefor which supplies and controls DC current through each of the motor windings such that no current is induced into the control winding from adjacent windings. The stepping motor precisely controls the rotation of an eccentric cam engaging an actuating plunger which actuates a control valve of the hydraulic actuating system. The driver receives control signals from a computer programmed to calculate, from user input command signals indicative of the desired system condition, and generate those control signals which most quickly achieve a rough approximation of the desired system condition. After this rough approximation is attained, the computer generates new control signals for the driver as a function of feedback signals and/or system component characteristics so as to precisely achieve the desired system condition.

Abstract: A control system is provided for a hydraulic actuating system having a multi-phase stepping motor with a driver therefor which supplies and controls DC current through each of the motor windings such that no current is induced into the control winding from adjacent windings. The stepping motor precisely controls the rotation of an eccentric cam engaging an actuating plunger which actuates a control valve of the hydraulic actuating system. The driver receives control signals from a computer programmed to calculate, from user input command signals indicative of the desired system condition, and generate those control signals which most quickly achieve a rough approximation of the desired system condition. After this rough approximation is attained, the computer generates new control signals for the driver as a function of feedback signals and/or system component characteristics so as to precisely achieve the desired system condition.

Abstract: A four-way valve is provided, for selectively interconnecting pressure supply and return lines with control pressure lines of a hydraulic device, having means for independently balancing the valve against pressures exerted on the valve by any one or more of the pressure lines and at any operating position of the valve. These pressures exerted on the valve would otherwise restrict or prevent actuation of that valve. This balancing means exposes a minimum surface area of the valve to high pressure forces and isolates the fluid pressure in the pressure lines until interconnection is made by valve actuation.

Abstract: An automatic tool turret for a lathe including a base adapted to be detachably secured to the lathe way. A tool carrying head is mounted on the base for movement between a clutched work performing position and unclutched head rotating position. The movement is hydraulically accomplished so that the head is supported by a hydrostatic bearing created by the hydraulic fluid. The fluid pressures generated during the movement of the head between its clutched and unclutched positions is used to initiate a work performing operation and to initiate turning of the head.