Abstract: A solenoid powered flow control valve in which the valve spool has split the pump flow across a primary metering orifice and a pilot metering orifice which regardless of spool position maintains a substantially constant flow ratio between the main and pilot flow. The valve spool is controlled by opposing servo chambers which sense the pressure drop in the pilot flow path across a solenoid powered variable orifice.

Abstract: A control circuit comprises pressurized fluid source (11), a two-position directional control valve (14) and an actuator (13), such as the pump of a hydrostatic transmission, connected to the fluid source and the control valve to be selectively actuated thereby.

Abstract: A device for controlling both the displacement of, and the transmittal of force by, a longitudinally movable driving apparatus comprising a piston rod which is hydraulically movable inside a cylinder, an emitter and receiver for ultrasonic waves, which are transmitted between a movable and a fixed part of the driving apparatus, a logic circuit and a controllable source of force, said receiver being electronically connected to said controllable source of force via said logic circuit.

Abstract: A drum brake assembly provides a pair of brake shoes which are movable by a hydraulic actuator to a braking position. The hydraulic actuator is carried by a backing plate and the pair of brake shoes is movable relative to the backing plate. A piston is slidably mounted within a bore on the hydraulic actuator and pressurized fluid communicated to the bore acts against the piston to move the piston and pair of brake shoes. A partition is also disposed within the bore to substantially define a secondary chamber which receives pressurized fluid from the bore. The partition is movably disposed within the bore and resiliently engaged with the piston so that increased pressure within the bore is transmitted to the piston via the partition and the resilient engagement. Moreover, the partition controls venting of the secondary chamber so that upon contact of the pair of brake shoes with a drum, backlash or retraction of the pair of brake shoes is limited.

Abstract: A first control valve of a fluid circuit connecting a first pump to a fluid motor has a signal port in communication with an inlet port when the first control valve is at a selected position at which substantially the total output of the first pump is directed to the motor. A valve device connects a second pump to the fluid circuit in response to a valve spool of the first control valve being moved to said selected position. The valve device has a valve member movable between a first position at which the second pump is in communication with a tank and a second position at which the output of the second pump is combined with the output of the first pump in the fluid circuit. A device moves the valve member to the second position in response to the valve spool of the first control valve being moved to said selected position. The device includes first and second actuation devices associated with the first and second ends of the valve member.

Abstract: A pressure responsive sequence device wherein in order to carry out the pressure responsive sequencing operation in both the meter-in and meter-out flow control modes, between a supply line and a discharge line of a primary actuator is inserted a switching valve which automatically switches, in response to the pressure difference between the supply and discharge lines, to communicate either of them having a lower pressure than the other with a tank through a low pressure relief valve; and a sequencing valve is inserted in a supply line which communicates a pump in a hydraulic power source with a secondary actuator.

Abstract: A two-stage regulator valve, particularly for regulating the operation of single acting hydraulic lift motors in lift trucks, which embodies a spool valve controlling first and second ports in the valve body and responsive at one end to lift motor fluid pressure. At the opposite end the valve is responsive first to the force of a first spring which closes the spool on one port when lift motor fluid is below a predetermined pressure, and secondly, following predetermined compression of the first spring during which both ports are opened to exhaust pressure fluid from the lift motor, to the added combined force of a lift motor pressure responsive piston and a second spring. The piston forms with the spool valve a differential area response to said fluid pressure and together with the second spring regulates the position of the spool valve so as to variably restrict the other port to control the exhaust from the lift motor inversely as a function of the fluid pressure therein.

Abstract: A device for accelerating the initial stroke of hydraulic jacks, comprising a cylinder, a piston provided with sealing-rings, said cylinder fluid feed-orifices and orifices for exhausting fluid through a plurality of calibrated ports arranged in rows in the cylinder periphery at both ends thereof, characterized in that at least one piston-ring (S.sub.2, S.sub.4) at one end of piston (P) is mounted in its respective groove (R.sub.1) with a certain amount of axial and lateral clearance, said groove communicating with the bottom of the piston through at least one port (B.sub.1).

Abstract: A safety valve for use in a compressed air line having a supply valve and a control valve, to prevent inadvertent sudden shifting of the controlled part when the line is exhausted and later repressurized. The safety valve comprises a normally closed piston-operated poppet valve, the piston chamber and outlet port being connected to the supply port through a bypass with an adjustable restriction upstream of the valve member. In one embodiment, the adjustable restriction comprises a replaceable plug threaded in the valve body. In a second version, the adjustable restriction comprises a needle valve mounted in a housing cover.

Abstract: The invention relates to a hydraulic control apparatus of the type used in vehicle steering systems. In all such systems there is a reversible type hydraulic motor connected to the steering linkage. The motor has complementary expansible chambers. With the use of control means pressurized fluid is selectively delivered to one chamber which is caused to expand concomitantly with the collapsing of the other chamber from which fluid is returned to a sump. There is provided in the control and power circuit throttle valves having respective opening positions which correspond to the pressure difference on both sides of the valves. Between the passages which extend to the two control circuit throttle valves is a pressure comparator which is operable to vary the pressure upstream of the power circuit throttle valve in proportion to the pressure upstream of the control circuit throttle valve.

Abstract: In order to automatically switch an open circuit type hydraulic actuating circuit to the meter-in flow control system when the direction of the load is positive or to the meter-out control system when the direction of the load is negative or is reversed to negative, thereby controlling the speed of the load, there is provided a hydraulic actuating system in which an amplifier valve assembly of the type which may produce a main flow whose flow rate is amplified with respect to that of a pilot flow in proportion to the ratio of the opening area of a detector orifice inserted in a pilot flow passage to the opening area of a main orifice inserted in a main flow passage, is hydraulically and operatively combined with a meter-in flow control valve for controlling the flow rate of the pilot supply flow in the amplifier valve assembly, a meter-out flow control valve for controlling the flow rate of the pilot return flow, and a switching valve inserted between the pilot supply and return flow passages and adapted to b

Abstract: An acceleration/deceleration device which, in order to achieve shockless acceleration/deceleration control in starting or stopping of the load by means of a hydraulic actuating circuit of the open circuit type, uses an amplification valve of a type such that the main flow rate may be amplified in proportion to the area ratio between a detection orifice installed in a pilot flow passage and a main orifice installed in the main flow passage and is constructed by combining the said amplification valve with a flow rate control valve for controlling the pilot flow and a control circuit for gradually changing the area of the opening of the main orifice.

Abstract: A hydraulic circuit for a tree harvesting implement having a cutter mounted on a movable frame with a hydraulic ram moving the frame and a hydraulic motor driving the cutter is disclosed herein. The hydraulic circuit includes two separate pressurized fluid sources with one source connected to one end of the fluid ram and the second source connected to the hydraulic motor as well as the opposite end of the fluid ram with both conduit means having pressure relief valves that are settable so that the frame is moved as a function of the resistance encountered by the cutter and/or the movable frame.

Abstract: A control system for controlling the operation of a valve actuator. The system includes a control valve for conveying operating fluid to the actuator in response to an actuator control signal. A single conduit operably connected to the actuator control valve both supplies operating fluid to the control valve and conveys an actuator control signal to the control valve.

Abstract: A conveyor apparatus for elevating loose bulk material from one level to another, as in self-unloading ships, and more particularly a dual belt conveyor-elevator having a relatively long horizontal feed section, and further including a belt take-up apparatus and system including a normal pressure mode for tensioning the outer belt of the dual belt conveyor-elevator under normal operating conditions, the belt take-up apparatus and system also including a high pressure mode which is connected in tensioning relation to the outer belt of the dual belt conveyor-elevator upon loss of motive driving power to the dual belt conveyor-elevator. The high pressure mode is capable of substantially immediately taking up slack which develops in the outer belt, particularly in the horizontal feed portion thereof, with consequent prevention of spillage of load material, when the driving power for the dual belt conveyor-elevator is interrupted.

Abstract: The invention relates to a hydraulic control apparatus of the type used in vehicle steering systems. In all such systems there is a reversible type hydraulic motor connected to the steering linkage. The motor has complementary expansible chambers. With the use of control means pressurized fluid is selectively delivered to one chamber which is caused to expand concomitantly with the collapsing of the other chamber from which fluid is returned to a sump. Forces transmitted to the hydraulic motor through the steering linkage by reason of the wheels striking objects such as stones or curbs cause an objectionable effect by reason of fluid being forced out of the motor back into the system. This effect is avoided by providing two valve assemblies for the two ports of the reversible motor which function in the absence of a steering command as ordinary one way check valves which prevent the undesired flow of fluid from either of the motor ports.

Abstract: A valve is used in a system employed on a vehicle for effecting the selected automatic disengagement of the transmission or main clutch upon the application of the vehicle service brakes, as well as the reengagement of the transmission when the brakes are released. Such valve allows rapid pressure buildup to the brakes, so that they may be rapidly applied, but delays the release of the brakes to allow ample time for reengagement of the transmission.

Abstract: A hydraulic power booster system having a power piston which may be adapted to be connected with an input member of a brake master cylinder and which is actuated when hydraulic pressure fluid is introduced into a power pressure chamber defined at one side of the power piston. An orifice is disposed between a hydraulic pressure source and hydraulic pressure reservoir with an opening that is restrictable for establishing a hydraulic pressure drop thereacross when a brake pedal is actuated. A control valve introduces the hydraulic pressure fluid from the pressure source to the power pressure chamber in response to a pilot hydraulic pressure established in a pilot chamber defined by the control valve upstream of the orifice. The flow of controlled hydraulic fluid through the pilot chamber becomes restricted for establishing the pilot hydraulic pressure therein when the brake pedal is actuated for restricting the opening of the orifice and thus establishing a hydraulic pressure drop thereacross.

Abstract: A torque-applying apparatus having one or more torque motors each arranged for forcibly threading a first threaded member into tightened association with a corresponding second threaded member. A control is provided for controlling the operation of each torque motor to firstly seat the first threaded member relative to the second threaded member by a rapid threading operation at a low torque. When the seated condition of all of the threaded members is sensed, the control automatically operates each torque motor to slowly apply gradually increasing higher torque to provide a preselected maximum-torque, tightened condition of the threaded members.

Abstract: A booster for a fluid pressure operated system in which relatively low pressure is used in the system and the booster is designed to be positioned immediately adjacent the fluid operated mechanism so as to eliminate the need for high pressure fittings and components. The booster has a spool which is shiftable in response to pressure build up in the mechanism. The spool acts as a sliding valve to direct fluid flow through a pressure converter such as a turbine or volumetric motor-pump located inside the spool.

Abstract: A safety valve for use in a compressed air line having a supply valve and a control valve, to prevent inadvertent sudden shifting of the controlled part when the line is exhausted and later repressurized. The safety valve comprises a normally closed piston-operated poppet valve, the piston chamber and outlet port being connected to the supply port through a bypass with an adjustable restriction upstream of the valve member. In one embodiment, the adjustable restriction comprises a replaceable plug threaded in the valve body. In a second version, the adjustable restriction comprises a needle valve mounted in a housing cover.