Abstract: A hydraulic booster for a vehicle and more particularly an improved hydraulic booster with improved brake-relieving action, among other improvements.

Abstract: A railroad car brake system, comprising, a pneumatic-to-hydraulic transducer connected to a brake control unit for developing braking pressure in response to a brake command request, and a plurality of disc brake units connected to the pneumatic-to-hydraulic brake pressure transducer and being characterized by the fact that the disc brake units are divided into high speed disc brake units and low speed disc brake units and a control valve is installed between the brake pressure transducer and the disc brake units so that the pressurized fluid may be supplied from the brake pressure transducer either to the high speed disc brake units, or to the low speed disc brake units.

Abstract: An electromagnetic valve control system employing a controller circuit for controlling the position of a pneumatic valve by regulating the magnetizing current provided to the electrical solenoid by establishing a first magnetizing current set point when the valve is to be moved from a release position to a lap position and by establishing a second magnetizing current set point when the valve is to be moved from an application position to a lap position.

Abstract: When a hydraulic circuit for driving actuators of a construction machine or the like includes a single hydraulic pump and a plurality of direction changeover valves connected to the hydraulic pump for controlling the respective actuators, operation of one of the direction changeover valves may result in undesirable change in the output oil pressure of the other direction changeover valves. The inventive hydraulic circuit includes means for driving a regulator of the hydraulic pump in response to any oil puressure change at the inlets of the direction changeover valves corresponding to the output oil pressure change, thereby compensating for the pressure change.

Abstract: A braking system for a vehicle which includes a master cylinder, and a wheel cylinder for braking a wheel with a brake fluid pressure supplied from the master cylinder. A pulsating-pressure absorbing apparatus is arranged between the master cylinder and the wheel cylinder. The pulsating-pressure absorbing apparatus includes a main body, an inlet formed in the main body and connected to the master cylinder, an outlet formed in the main body and connected to a side of the wheel cylinder, and a stepped hole formed in communication with the inlet and outlet. A stepped plunger is slidably fitted into the stepped hole, and a check valve is arranged in a path defined within the plunger for permitting brake fluid to flow from the inlet towards the outlet and for inhibiting brake fluid from flowing from the outlet towards the inlet.

Abstract: In a fluid pressure control apparatus for a vehicle which includes a main body in which an input opening is formed in communication with a master cylinder side and an output opening is formed in communication with a wheel cylinder side, a stepped bore made in the main body, in communication with the input opening and output opening; a stepped piston slidably fitted into the stepped bore, a poppet type movable body for limiting fluid flowing from the wheel cylinder side towards the master cylinder side in response to a predetermined length movement of the stepped piston; a path for connecting the input opening side of the stepped piston with the output opening side of the stepped piston; and a valve for closing the path in response to a movement longer than the predetermined length.

Abstract: There is disclosed a liquid-operated booster having a jump-up function, in which the production of an internal pressure in a reaction force chamber in accordance with a reduction of the volume of the reaction force chamber is prevented. To achieve this, a mechanism for relieving the reduction of the volume of the reaction force chamber due to a relative movement of a piston and an input member toward each other is provided at a position facing the reaction force chamber. Most preferably, this relieving mechanism is constituted by a movable small piston provided at the side of an operating input.

Abstract: A control valve device for a railway car having an arrangement for changing the axial position of a variable area piston in order to adjust the output pressure of a piston valve assembly in accordance with a high or low speed of the railway car. The axial position of a supply valve seat is set in accordance with a high or low speed signal to in turn set the axial posiiton at which the piston assembly, including the variable area piston, assumes a lap condition.

Abstract: A variable load valve device for a railway car having an arrangement for changing the axial position of a variable area piston in order to adjust the output pressure of piston valve assembly in accordance with different load weights of the railway car. The axial position of a supply valve seat is set in accordance with a load weight signal to in turn set the axial position at which the piston assembly, including the variable area piston, assumes a lap condition.

Abstract: A pump apparatus includes a plunger, an eccentric cam for moving the plunger toward a pressure chamber, a drive shaft supporting the eccentric cam, and an output shaft of a motor for imparting a rotational force to the drive shaft. A convex portion is formed on one end of one of the drive shaft and the output shaft whereas a concave portion is formed in one end of the other of the two shafts. The convex portion is fitted in the concave portion to interconnect the drive shaft and the output shaft. The convex portion is fitted in the concave portion with a clearance therebetween. A holder member for always holding the convex portion and the concave portion in engagement with each other in the direction of rotation of the drive shaft is provided at an area of fitting between the convex portion and the concave portion. With this arrangement, noises resulting from the impingement of one of the convex portion and the concave portion upon the other during the operation of the pump apparatus are eliminated.

Abstract: A load compensation control valve for an air brake system for railway vehicles having air springs for producing control pressures proportional to the load sustained by the given vehicle. The load compensation control valve includes a supply chamber, an output chamber, a supply vlave, a supply valve seat, an exhaust valve rod, a balance piston, and an adjusting mechanism for controlling the pressure in the output chamber in accordance with the level of the control pressures.

Abstract: An automatic pressure control device built in a hydraulic actuator driving circuit for driving a plurality of actuators of a construction machine or the like by a single hydraulic pump through respective pilot changeover valves is provided for automatically shuttling the changeover valve of each actuator to reduce its demanded flow rate and uniformly control the operation speeds of all actuators. To this end, the device is arranged to drain an excessive flow rate of the hydraulic pump through a series connection of a flow rate control valve controlled by the highest load pressure of the actuators and a resistance passage including a shuttle and to control the pilot pressure of each pilot changeover valve in response to a pressure at the junction of the series connection.

Abstract: A tube seat installation device having a piping connecting part of a special coupling joint being attached on one side of the input piping opening or the output piping opening of the fluid pressure valve while at the same time having a cylindrical part of the special coupling joint fitted into a connecting hole of the tube seat via an O-ring sealing element. The piping connecting part of the special coupling joint is attached to the other side of an outlet piping opening or an inlet piping opening. The cylindrical part is fitted into the introduction part of the hollow body via an O-ring sealing element, or the introduction part of the hollow body is attached to the piping opening via an O-ring sealing element. A flange part of this hollow body is faced and fixed to another connecting hole of the tube seat via O-ring sealing element to which a fluid pressure valve is fixed by being sandwiched by the hollow body.

Abstract: A pipe coupling consisting of male and female elements for connecting and disconnecting a hydraulic or pneumatic piping used for industrial machinery. Each coupling element includes a check valve therein which is actuated by connecting and disconnecting operation to automatically open the passageway of the coupling when it is connected and to automatically close it when it is disconnected.The inventive pipe coupling is designed for use with a conventional automatic connecting and disconnecting device such as automatic coupling device for large scaled industrial machinery.

Abstract: A hydraulic motor control circuit for use in a device for driving construction equipment, such as shovel loader, which comprises a hydraulic driving motor, a pump for feeding compressed oil to the hydraulic motor and a tank for receiving the compressed oil discharged from the hydraulic motor. The circuit comprises a pilot operation type main valve for controlling the oil flow between the pump and the motor and between the motor and the tank, and a remote control valve for feeding a pilot oil pressure to a pilot chamber of the main valve to turn the main valve to a first position for driving the hydraulic motor. As a feature of this invention, the control circuit further comprises an apparatus for detecting the slanting angle of a downward slope and feeding an oil pressure corresponding to the slanting angle to a second pilot chamber of the main valve.

Abstract: In a mechanical component, a component body includes an opening, a first bore located at the opening and having a diameter of D.sub.1, and a second bore located on the opposite side of the first bore from the opening and having a diameter of D.sub.2, where D.sub.1 is larger than D.sub.2. A step is formed through which the first and second bores are connected to each other. An annular dish-shaped plate is urged against the step of the component body until the dish-shaped plate is deformed into a planar-plate configuration, to bite an outer periphery of the dish-shaped plate to a periphery of the first bore. Thus, an annular element formed by the dish-shaped plate is fixedly mounted to the component body. If the above-mentioned support structure is applied to a valve spring of a hydraulic pressure control valve, it is possible to surely stabilize the support of the valve spring.

Abstract: In a hydraulic pressure control valve for use with a master cylinder, a valve chamber is formed at an attaching section of a valve body. An annular recess is formed in the valve body at a location of an end of the stepped bore, which opens to the valve chamber. A valve element is arranged within the valve chamber for movement therewithin. The valve element has a stud which extends to an interior of the master cylinder and which receives, from the piston within the master cylinder, such a force as to cause the valve element to fall down. An annular preventing element is formed separately from the valve element and the valve body. The preventing element is arranged between the valve element and the end of the stepped bore, which opens to the valve chamber. The preventing element substantially covers an annular end of the annular recess, which opens to the valve chamber, for preventing a seal element from coming out of the recess, which is arranged therewithin.

Abstract: A flow control device includes a control valve having a discharge line to be connected to a hydraulic motor, a supply line to be connected to a hydraulic pump, a first bleed-off control passage having a line connected to a tank, and a second bleed-off control passage having a line connected to the tank through a secondary control valve, a flow dividing valve provided in the supply line and having a first position for allowing a first desired flow of oil discharged from the hydraulic pump and a second position for allowing a second desired flow of the oil, and a selector valve operable for the secondary control valve and the flow dividing valve and having a first selection position for closing the secondary control valve and shifting the flow dividing valve to the first position and a second selection position for opening the secondary control valve and shifting the flow dividing valve to the second position.

Abstract: A filter arrangement for a moisture-removal device used in compressed air systems in which an inner filter adapted to remove water from the air is encircled by an outer filter that is adapted to remove oil from the air. A space between the inner and outer filters is provided to accommodate accumulation of the filtered-out oil with a valving arrangement provided in the area of oil accumulation that is operative in response to a pressure differential when the regeneration phase of operation is initiated to concurrently discharge the accumulated oil.

Abstract: A double operate check valve used in a hydraulic pressure circuit for locking and unlocking a vibration absorbing hydraulic cylinder included in a wheel suspension mechanism of a vehicle, which includes an improvement in its structure for providing the suspension with improved compliance with respect to road surface undulation and corresponding comfortable drive of the vehicle. The check valve pilot pistons have fluid conducting surfaces which are connected by a valve body passageway and which communicate the main fluid paths when hydraulic pressure in the pilot chamber urges the pilot pistons to open the check valves.