摘要:
A system that can recover flows of a hydraulic pressure fluid returned from a plurality of hydraulic actuators is disclosed which includes a plurality of fluid recovery circuits (15, 19, 25 and 27) into which flows of a hydraulic pressure fluid returned from such a plurality of actuators are admitted, and a main fluid recovery circuit (36). There is provided a selector means (30, 31, 32, 33, 34, 35, 37) for permitting at least one of the plural fluid recovery circuits (15, 19, 25 and 27) selectively to communicate with the main fluid recovery circuit (36). The system, by permitting at least one of a plurality of fluid recovery circuits to communicate with a main fluid recovery circuit, enables a hydraulic return pressure fluid from at least one of a plurality of actuators to be recovered and hence is applicable to a working machine involving a plurality of hydraulic actuators.
摘要:
An actuation system particularly for the operation of a vehicle clutch and/or gearbox ratio selector members in which a pump charges an accumulator via a non-return valve. A slave cylinder receives pressurised fluid from the accumulator via a solenoid-operated control valve. The control valve also controls the exhaust of fluid from the slave cylinder. The control valve has a rest position in which pressurised fluid from the pump is returned to sump and the slave cylinder is vented to sump, a first energised position in which the return of pressured fluid to sump is cut-off and the slave cylinder remains vented to sump, and a further energised position in which venting of the slave cylinder is cut-off and the slave cylinder is supplied with pressurised fluid from the accumulator. The pump may be electrically driven and stopped when the accumulator pressure is above a pre-determined level.
摘要:
In a flow control device for vehicles and like, a union 17 of a pump receives a load pressure responsive valve 24. The union 17 is provided with outlet port to supply operating fluid regulated by a flow control valve to a control valve. The load pressure responsive valve, received in the union, has a variable orifice. The load pressure responsive valve brings the spring chamber into communication with the reservoir when road pressure, caused by operation of a steering wheel, is relatively low and the load pressure responsive valve shuts the communication between the spring chamber and the reservoir in response to rising of the road pressure. Therefore, the flow control device provides the power saving caused by decreasing the flow rate supplied from the pump to the control valve at low load pressure without substantial improvement of a pump housing.
摘要:
In order to stretch an injection-molded preform by a stretching rod in the axis direction and to blow mold it into a hollow product such as a vessel with a predetermined shape in a blow mold, some of the blow air after used is collected in a low-pressure working-air tank set separately from a high-pressure blow-air tank and operating selector valves in a circuit and the collected air is used for some of the working air for an air cylinder for operating units related to stretch-blow molding by air cylinders. To decrease the availability factor of a compressor by collecting used blow air and thereby, make it possible to cut the cost required for compressed air and decrease exhaust noises.
摘要:
A method for butt welding first and second thermoplastic pipes to each other including the steps of locating the end portions of first and second pipes to be joined in clamps that are moveable towards and away from each other by the application of hydraulic pressure, the pipe end portions being moveable against a facer for trimming the pipe ends at a first predetermined optimum hydraulic pressure, moveable against a heater for heating the pipe ends to a molten state at a second predetermined optimum hydraulic pressure and moveable towards each other while the ends are in a molten state to fuse the pipes at a third predetermined optimum hydraulic pressure, determining the hydraulic pressure required to move the pipe end portions towards each to determine a drag force hydraulic pressure, adding the drag force hydraulic pressure to each predetermined optimum hydraulic pressure to obtain first, second and third operating hydraulic pressures, and butt welding the pipes to each other using the first, second and third determined operating hydraulic pressures.
摘要:
The present invention proceeds from a control arrangement for at least two hydraulic consumers which has a positive displacement pump the setting of which is variable by a load-sensing regulator which can be acted on via a load-signaling line by the highest load pressure, on which a maximum-pressure and an output regulation are superimposed, two displaceable metering diaphragms a first one of which is connected between the positive displacement pump and a first hydraulic consumer and the second between the positive displacement pump and a second hydraulic consumer, and two pressure compensators a first one of which is arranged behind the first metering diaphragm and the second behind the second metering diaphragm and the regulating pistons of which can be acted on, in opening direction on a front side, by the pressure behind the corresponding metering diaphragm and in closing direction on the rear side by the pressure in the load-signaling line. In order that the pump pressure does not become maximum, since, upon simultaneous actuation of the two hydraulic consumers, the one consumer is moved against a stop or carries out a clamping function, it is provided that, in the event of such joint control of only the first and the second hydraulic consumers, the load-sensing regulator as from a limiting pressure which lies below the maximum pressure can be acted on by a pressure which is dependent only on the load pressure of the one first hydraulic consumer.
摘要:
A hydraulic control system has a closed center control valve disposed to control flow of pressurized fluid from a pump to an actuator and a bypass valve disposed to control fluid flow through a bypass line connecting the pump to a reservoir. A controller connected to the control valve and the bypass valve is operative to controllably move the control valve toward an open, flow communicating position and the bypass valve toward a closed flow blocking position. A pressure compensating valve is disposed in the bypass line to maintain a predetermined pressure differential across the bypass valve when the pressure upstream of the bypass valve exceeds a predetermined level so that the flow through a area opening in the bypass valve is substantially commensurate with the opening at pressures above the predetermined level.
摘要:
The procedure serves the purpose of molding a container from a thermoplastic material. After a temperature treatment a moldable object is fed to a blow station, which has a blow mold that is provided for the purpose of contouring the container. The temperature-treated moldable object is inserted into the blow mold. By feeding in high-pressure blow air, the moldable object is expanded. In addition at least one other pneumatic working step with low-pressure air is carried out, with this air being taken from a low-pressure air supply. The low-pressure air supply has a smaller pressure level than the high-pressure blow-air supply. After the moldable object has been expanded, high-pressure blow air streaming out of the molded container held in the blow mold is fed to the low-pressure air supply during a transition phase. In the region of the low-pressure air supply a pressure monitoring is carried out for the purpose of defining a maximum low-air pressure to be provided. After the transition phase a venting of the container that is held in the blow mold is performed vis-a-vis an ambient pressure.
摘要:
A variable priority device for heavy construction equipment for establishing a priority of the boom over the bucket by limiting an amount of fluid passing through a bucket-side parallel fluid line when the boom operates alone and thereby decreasing the amount of fluid supplied to the bucket actuator. The device is installed in the bucket-side parallel fluid line and adapted to be switched between an orifice state and an orifice release state, the priority control valve being initially maintained at the orifice release state by a resilience device while being switched from the orifice release state to the orifice state against a resilience of the resilience device in response to a pilot pressure for moving the spool of a boom-side switching valve communicating with the boom actuator.
摘要:
A linear hydraulic actuator has a reciprocating pump which provides pressurized hydraulic fluid contained in a reservoir to a hydraulic cylinder in which slides a piston which supplies the actuator output. A diverter valve in flow communication with the pressurized hydraulic fluid has an adjustment shaft allowing manual adjustment of the rate of flow of pressurized hydraulic fluid to the cylinder. Preferably the pump is immersed in the hydraulic fluid held by the reservoir, and the adjustment shaft of the diverter valve penetrates a wall of the reservoir to allow external adjustment of the diverter valve.