Abstract: A metering lockout check valve which lowers gravity loads without chatter. The poppet has a conical concave face which surrounds an annular seat and is shaped so that as the poppet opens, the effective closing force increases requiring higher pressures in the opposite motor port to open the poppet. Conversely an overrun condition is prevented since when the pressure drops in the pump pressure side of the circuit, the poppet will reduce its opening and provide a metering function.

Abstract: A control arrangement for a hydraulic motor has an adjustable pressure medium supply device with a container, an unblockable check valve with a control connection, a plurality of chambers including a supply chamber, a motor chamber, first and second return chambers, and a control chamber, a control slider displaceable relative to the chambers, wherein a control conduit extends from the supply device and leads to the control chamber, a first pressure control member is arranged on the control slider so that in a lowered position of the latter the first pressure controlling member is located between the control chamber and the second return chamber and the control slider in its raised position blocks the control chamber, and a second pressure controlling member located between the control chamber and the motor chamber and opening into the latter.

Abstract: An energy-saving hydraulic driving arrangement includes a motor having two chambers separated by a reciprocable or angularly movable output element which can accelerate or decelerate a mass. One of the chambers receives pressurized fluid from one of a battery of accumulators containing fluid at different pressures (namely, from the accumulator wherein the pressure is slightly higher than the desired pressure in the one chamber) during acceleration of the output element while the other chamber discharges fluid directly into a sump. During deceleration of the output element, the one chamber draws fluid directly from the sump whereas the other chamber discharges pressurized fluid into that accumulator wherein the pressure is slightly less than the pressure of fluid in the other chamber.

Abstract: A piston arrangement with a metal shaft, a piston head that is attached to it with a shrink ring, and a member made of partially stabilized zirconium ozide. The top which demarcates the combustion chamber, of the piston head, consists entirely of the member made of partially stabilized zirconium oxide. The bottom of the zirconium-oxide member is a truncated cone and the top of the shaft is a truncated cone. They are surrounded by an annular component that is split into two sections parallel to the longitudinal axis of the piston. The annular ocmponent is secured with an outside shrink ring.

Abstract: In connection with a plunger piston for internal combustion engines, the connecting rod, which is hinged thereto via a gudgeon pin, is laterally guided at its small end by being in abutting contact with the internal faces of the gudgeon pin bosses. For this purpose, there are provided, only in the zone at the level of the gudgeon pin axis, limited contact surfaces between the connecting rod small end and the gudgeon pin bosses. By this means, the influence of deformations of the piston on the guidance of the connecting rod is eliminated to a very large extent.

Abstract: A power transmission system is provided, suitable e.g. for driving an electrical vehicle from a power supply such as on an electrochemical battery. The system provides an electric motor having two relatively rotatable motor portions. Each motor portion is relatively rotatable to an anchorage or mounting for the motor, coaxially with the axis of rotation between the motor portions. One motor portion is provided with the power output for the system and the other motor portion is drivingly connected to a hydrostatic machine capable of acting as a pump or motor which is in liquid flow communication with a hydrostatic accumulator and liquid source.

Abstract: A pump jack having a walking beam oscillated in a vertical arc by a hydraulic actuating cylinder that receives pressurized hydraulic fluid from a variable displacement pump. The hydraulic actuating cylinder is controlled by a hydraulic valve having an operating member mechanically shifted by a second hydraulic actuating cylinder near the end points of the pivotation arc of the walking beam to reverse the direction of movement of the walking beam during the shifting of the operating member of the hydraulic valve. The second hydraulic actuating cylinder is controlled by a second hydraulic valve that transmits pressure to the second hydraulic actuating cylinder from the variable displacement pump and reverses the flow of pressurized hydraulic fluid to the ports of the second hydraulic actuating cylinder near the end points of the pivotation arc of the walking beam.

Abstract: There is disclosed a hydraulic circuit system for use in a swivel type excavator. The circuit system having a plurality of variable displacement pumps for supplying pressurized fluid for manipulations of work implements and swivel means of the excavator, and control means operative to automatically adjust pump displacement to the output hosepower of a prime mover driving the pumps. The control means includes hydraulic pressure detector means, servo-control means respectively provided in the pumps, negative control valves for respectively controlling the servo-control means by the action of the pressure detector means, cut off valves respectively connected in series with the negative control valves, and summing valves respectively connected in series with some of the cut off valves so as to control pressurized fluid to be supplied into the servo-control means by the action of the fluid pressure delivered from the pumps.

Abstract: A control system for a hydrostatic power transmission having a variable displacement hydraulic pump (2) and a hydraulic actuator (3) connected in a closed or semi-closed circuit, wherein the displacement of the pump or the delivery thereby is adjustable in accordance with a manipulated variable of an operating lever (13). A control unit of the system (16) is operative to calculate a hydraulic pump displacement command (X) on the basis of a manipulated variable signal (X.sub.

Abstract: A hydraulic circuit system of a construction machine having first and second hydraulic circuit, and a bypass circuit for connecting the first and second circuits together. The first circuit includes a first hydraulic pump and a first valve group having a plurality of directional control valves for controlling a flow of hydraulic fluid from the first pump, and the second circuit includes a second hydraulic pump and a second valve group having a plurality of directional control valves for controlling a flow of hydraulic fluid from the second pump. A plurality of actuators are driven by the hydraulic fluid supplied from the first and second pumps through the valves. The bypass circuit includes a bypass line for connecting the first travel valve in series with the second travel valve in a position downstream thereof through the selecting valve.

Abstract: The star-shaped rotor (10) accommodated in a discoid cavity (9) defines first chambers (27) formed in the arms (20) of the rotor and second chambers (26) for receiving fluid under pressure delimited between two adjacent arms of the rotor, the constitutive elements of the stator (3-5) being joined together by fastening means (50) extending through the second chambers (26), the lateral faces of the cavity opposite the stator incorporating passage apertures (32', 33) which have a trapezoidal profile with radial edges coincide substantially with the web zones (31) of the arms of the rotor, the edges of which define with the edges of the apertures adjustable restrictions (250, 280) the first chambers (27) communicating permanently with return passages (38) in the stator.

Abstract: A pneumatic actuator for deploying flexible bodies and the like is disclosed. The actuator is a plurality of telescoping tubes made of high temperature resistant graphite material which are extended by the pressure of gases produced internally by a gas generator contained within the innermost tube. The extended tubes are locked in position automatically and venting of the gases from the tube interior is provided for simultaneously with full and locked extension of the tubes.

Abstract: A pneumatic door control equipped with a door control valve for operating a door drive to an open or a closed position. The door control valve has an opening and a closing solenoid-operated pilot valve and an opening and closing spool valve, each operable to a passage or a vent position. A shuttle valve is part of the control valve and works in conjunction with an operator-controlled emergency valve to vent both spool valves simultaneously. A differential pressure switch is connected to the door drive to sense abnormal pressure expended in a door-opening or closing movement. Such an occurrence will output a signal to an electronic switching device which also monitors, via limit switches, whether a door is fully opened or fully closed. If excess pressure occurs during a door-closing movement, the switching device will trigger the control valve to reverse to the opening position.

Abstract: A load responsive fluid power and control system in which the speed of the prime mover, driving a fixed displacement pump, is varied to maintain a constant pressure differential between pump discharge pressure and maximum system load pressure, above a certain predetermined system flow level and in which this constant pressure differential is maintained by pump flow bypass control, at system flows below this predetermined level.

Abstract: A filled piston (10) has a tube (19) extending axially through the core (13) of filler material. The tube (19) provides the passage (23) through which hydraulic fluid passes to lubricate the bearing surfaces of components associated with the piston (10). This eliminates the problem of the hydraulic fluid eroding the filler material and thus the need for visual inspection of the passage through the piston.

Abstract: A control system has two fixed-displacement pumps for supplying pressurized fluid to a pair of steering cylinders via a steering valve and to a pair of implement cylinders via an implement valve. Connected next to the pumps is a demand valve which is pilot operated to deliver to the steering cylinder pair the pressurized fluid from only one pump upon slight displacement of the steering valve and the pressurized fluid from both pumps upon greater displacement of the steering valve. The demand valve is further pilot operated to deliver to the implement cylinder pair the pressurized fluid from only one pump when the implement valve is actuated in a direction to lower the implement assembly, and the pressurized fluid from both pumps when the implement valve is actuated in a direction to raise the implement assembly.

Abstract: The piston has at least one first piston ring groove for receiving a first compression ring and a flame damper ring groove located above said first compression ring for receiving a floating type flame damper ring. According to the invention, on the outer surface of the flame damper ring there is provided a groove adapted to receive a second compression ring having tips defining a gap, the radial thickness of the second compression ring is lower than that of said first compression ring. The second compression ring is so conformed not to close on the tips when subjected to external pressure but to act with its inner surface on the bottom of its groove.

Abstract: A hydraulic coupling is disclosed which has a primary bladed wheel and a secondary bladed wheel confining a torus-shaped operating space. A blade-free ram space is provided inside the blading of the primary wheel. A delay chamber rotating with the primary wheel is connected by channels respectively to the ram space and to the operating space. In each of the channels, a switchable valve is provided which operates depending on the primary speed. A scoop tube is fixed to the secondary wheel. The scoop tube has inlet opening of the tube in the radially outermost region of the inner space of the coupling. The scoop tube directs operating fluid into the radially inner region of the coupling, from where the fluid can reach the delay chamber through the valve assigned to the channel.

Abstract: A motor vehicle having a pair of front drive wheels and a rear steerable drive wheel mounted on a main frame. A sub-frame secured to the main frame intermediate the front and rear drive wheels carries an internal combustion engine and a pump assembly. The pump assembly has a first pump operable to deliver fluid under pressure to fluid operated motors operably connected to the front drive wheels and a second pump operable to deliver fluid under pressure to a fluid operated motor operably connected to the rear drive wheel. The internal combustion engine and pump assembly are located below a seat and floor with both the engine and pump assembly positioned transversely of the main frame of the vehicle. The rear wheel is mounted on the frame for angular movement about a generally upright axis. A fluid operated double acting piston and cylinder assembly operates to angularly move the rear wheel about the upright axis to steer the vehicle.

Abstract: A fluid system (10) having a directional control valve (12) operated by a pilot valve (11) having a manually operable control handle (22) for selectively controlling a fluid motor (14) in positioning a load (17). The pilot valve (11) includes a spool (31) cooperating with associated portions of the pilot valve to provide a pressure regulated pilot signal to the directional control valve during normal operation of the system. Spool (31) includes a recess (98) which is placed in communication with the high pressure portion of the motor cylinder (16) during a dead engine condition by manipulation of handle (22) to provide pressure regulated delivery of the fluid from the motor (14) through recess (98) and to the conduit normally controlling the directional control valve for effecting a controlled lowering or retraction of the load. A single pilot valve is utilized for effecting the pressure regulated control in both normal and dead engine conditions.