Abstract: Various buoyant valve arrangements are utilized to prevent quick take-up pressure from entering the master cylinder reservoir chamber until the quick take-up pressure reaches the desired value. A resiliently biased check valve is provided which opens at a predetermined quick take-up pressure to limit the amount of quick take-up pressure generated and then vents excess brake fluid from the quick take-up chamber into the reservoir chamber. The check valve may be resiliently biased by a spring or by elastic tension in an O-ring valve member.

Abstract: A brake booster having a constant pressure chamber and a variable pressure chamber formed respectively at both front and rear sides of a power piston within a housing, characterized in that a hollow expansion body expansible axially of the power piston is disposed within the constant pressure chamber and one end of the hollow expansion body is secured fixedly to the housing while the other end of the expansion body is connected to a push rod so that the force magnifying ratio of the brake booster is varied by adjusting the internal pressure in the hollow expansion body.

Abstract: A housing (10, 12, 14) has first and second flexible membranes (32, 42) dividing it into two sealed chambers plus a third chamber from which the movable member (38) projects. Each membrane co-operates with a respective cup (40, 50) and return springs (54, 56) tend to urge both cups away from an end wall (26). The two cups are interconnected by a single piece member (58) which is inextensible but which can readily be bent in two to enable the cups to come into contact with one another. Each sealed chamber can individually be selectively connected to a source of reduced pressure via a respective orifice or pipe fitting (30, 28). The position of the movable member (38) can thus be changed.

Abstract: A bellows for protecting spindles, guideways, and the like of machine tools comprises a pleated cover having inner and outer cover elements and support members between adjacent pleats. The inner cover element has inwardly extending flaps which may be secured to the support members or to each other to form such support members.

Abstract: A mineral mining installation comprises a roof support unit and an advance mechanism. The roof support unit has a floor sill constituted by two floor girders. The advance mechanism comprises a hydraulic advance ram, the advance ram having a relatively-displaceable cylinder and a piston rod, and a device for selectively limiting the working stroke of the ram. The stroke-limiting device comprises a stop fixed to the cylinder of the advance ram, and an adjustable stop member which is mounted on the side wall of one of the floor girders.

Abstract: An electro-hydraulic control system includes a plurality of two-position control valves, each controlling fluid flow into and out of a corresponding one of a plurality of hydraulic functions. First and second pressure responsive servo actuators associated with each control valve operate to move each control valve to first and second positions, respectively. A two-position, solenoid-operated, pilot valve controls fluid flow into and out of a pilot circuit. The pilot circuit communicates fluid to and from the second servo actuator of each control valve and to and from a plurality of two-position, soleniod-operated, pilot valves. Each pilot valve controls fluid flow into and out of the first servo actuator of a corresponding one of the control valves. A detent mechanism holds each control valve in either its first or its second position in the absence of fluid pressure in the servo actuators.

Abstract: Hydraulic assistance device incorporating a casing provided with a bore in which a first piston is mounted so as to slide, the piston being able to move under the effect of a brake pedal between a first position, isolating a first chamber which is joined to the brakes of the vehicle, from a source of high pressure fluid, and a second position, causing the first chamber to communicate with the high pressure source, the device also incorporating a second chamber formed in the casing, a passage joining the first and second chambers and a valve mechanism in the passage in such a way that the passage is normally closed, under the effect of the pressure in the second chamber, characterized in that the device incorporates a second passage, causing the second chamber to communicate with a low pressure reservoir, and a second valve mechanism in the passage, the valve mechanism being sensitive to the pressures in the first and second chambers in such a way that the passage normally remains closed during the operation o

Abstract: A hydraulically operated impacting device includes a differential piston slidably disposed in a bore, and having an impacting surface and a piston rod facing at the other end a valve sleeve circumscribing the piston rod, there being an annular space between the rod and the valve, the valve having a first and a second position; a first duct leads from a pressure source to the bore and is governed by the valve for acting or not acting on the larger one of the two piston surfaces respectively in the first and second positions of the valve; a second duct leads from the source to the bore for acting on the smaller one of the piston surfaces; a third duct leads from the bore at a location below the valve to a ring chamber adjacent the valve, the valve having a collar which is movable in the ring chamber, the piston has a portion which depending on the position of the piston permits or prevents communication between the annular space and the third duct to obtain or not obtain pressurization of the ring chamber for s

Abstract: A speedup device or valve means comprises a check-valve disposed in an oil passage connected with the rod-end chamber of a double-acting cylinder for preventing working oil from returning toward a tank only, a circulation valve provided in the upstream of said check valve, said circulation valve being usually urged by a spring to block communication between the oil passages connected with the rod-end and the piston-end chambers, respectively, said circulation valve being designed to move against the spring so as to connect the oil passages with each other in response to the pressure rise in the return oil from the rod-end chamber when said double-acting cylinder is in its rod-extending motion, causing the return oil from the rod-end chamber to shift into the piston-end chamber through a variable restriction, and a circuit set up in a portion of said circulation valve for allowing a portion of the return oil from the rod-end chamber to return to the tank through a variable restriction and a restriction passage

Abstract: Various buoyant valve arrangements are utilized to prevent quick take-up pressure from entering the master cylinder reservoir chamber until the quick take-up pressure reaches the desired value. A resiliently biased check valve is provided which opens at a predetermined quick take-up pressure to limit the amount of quick take-up pressure generated and then vents excess brake fluid from the quick take-up chamber into the reservoir chamber. The check valve may be resiliently biased by a spring or by elastic tension in an O-ring valve member.

Abstract: A double action piston/cylinder unit has a piston guided in a cylinder and attached to a piston rod, the piston to be charged with a pressure agent, particularly hydraulic fluid at a first end face, the hydraulic fluid to be conducted in a controlled manner into the cylinder via a first fitting disposed at an end section of the cylinder and is to be charged at its other, second end face with a pressure agent which is located in an annular chamber formed by a central section of the piston rod and the inner wall of the cylinder, the second end face of the piston and a cylinder end piece, the annular chamber is in communication with a pressure agent reservoir which is connected to the annular chamber via a second fitting disposed at the other end section of the cylinder.

Abstract: A brake booster can switch operating mode from a positive-pressure mode using a signal-controlled fluid pressure supplier to a vacuum-pressure mode and vice versa. The booster includes a booster converter holding both an air valve and a vacuum valve of the booster closed in the positive-pressure mode or holding the booster air valve in its closed and open positions while holding the booster vacuum valve in its open and closed positions respectively when the brake pedal is released and depressed in the vacuum mode. The fluid pressure supplier is enabled while both booster valves are in the closed position in the positive-pressure mode.

Abstract: A switch and valve assembly for inflating or deflating a pair of bladders mounted in the back and seat regions of a vehicle seat. The assembly houses two normally-closed valve assemblies and two normally-open electrical switch assemblies, with two pushbutton-actuated stems adapted to selectively either partially open the valve assemblies by partial depression of the pushbuttons to thereby bleed-off fluid under pressure from respective bladders, or to fully open the valve assemblies while closing the switch assemblies by full depression of the pushbuttons to thereby actuate the pump to provide fluid under pressure to fill the respective bladders as desired for operator riding comfort or support. Pressures in the two bladders may be changed individually or concurrently.

Abstract: A hydraulic driving system for motorcycle gear shift includes a primary cylinder combination, a secondary cylinder and a set of delivery conduits for handling hydraulic fluid connected therebetween, in which two primary cylinders with different diameters are oppositely formed in a hollow portion of a motorcycle handle and the two primary cylinders are respectively fluidically communicated with the secondary cylinder to reciprocatively and linearly move a gear rack and to drive the shaft of the gear shift by rotating a twist bar, formed on the handle, having an inclined-plane tongue alternatively actuating the two primary cylinders in the handle.

Abstract: A device for controlling an adjustable arm 1 has an operating circuit 10 including a movable valve 3 with two control mechanisms 11, 12 bidirectionally actuated by pressure. A control circuit to activate the movable valve is connected to a pressure source 19, to the two control mechanism 11, 12, and to an adjustable throttle 22 attached to one of the two control mechanism 12. The control circuit also includes an adjustable throttle 24, series connected adjustable throttles 27, 28 attached to the other control mechanism 11 and a fifth adjustable throttle 57. The fifth throttle is used to create an additional actual value input. An adjustable control valve 53 employs the desired and actual value inputs supplied by the adjustable throttles in various ways by interconnecting the throttles with the control devices and a pressure ratio valve 45 so that the system responds to applied force, position or both.

Abstract: A vacuum booster assembly comprises front and rear shells of pressed sheet metal coupled to each other at their annular opening end portions, a power piston housed within the coupled shells, a diaphragm member attached to a pressure receiving portion of the power piston and having an outer annular bead clamped between the annular opening end portions of the shells, an inner annular bead coupled over a cylindrical portion of the power piston, a flexible portion extending along the contour of the pressure receiving portion of the power piston, and a pair of support portions formed to correspond with a pair of radial recesses formed in the pressure receiving portion of the power piston, a pair of support members attached to the support portions of the diaphragm member in such a manner to permit axial movement of the power piston, and a pair of tie bars extending in parallel respectively across the front shell, the support member, the support portion of the diaphragm member and the rear shell and fastened at oppo

Abstract: A reservoir (20) for a master cylinder (16) has a body (22) with an end member (82) attached thereto by tangs (92, 92' . . . 92.sup.N) that engage a surface (69) on a flange (70). A shoulder (86) concentric to peripheral lip (84) on the end member (82) retains a seal (96). A projection (90) that extends from the end member (82) acts as a stop to assure that a pin (52) on a lever (54) that carries a magnet (60) remains attached to arms (44) extending from the body (22). While motion may move the fluid in compartments (34 and 36) toward flange 70, shoulder (86) acts a first barrier and seal (96) acts as a second barrier to prevent fluid from leaking through the mechanically formed joint. If fluid is lost from the compartments (34 and 36) a float (58) tracks the fluid level and moves magnet (60) toward sensor (64) to inform an operator of the change in fluid level.

Abstract: Electrohydraulic regulating device, particularly for aircraft controls, iuding a regulating cylinder having a regulating piston therein capable of being loaded at either end thereof for the positioning of which necessary volumes of operating fluid can be supplied separately to either end space of the cylinder by means of magnetically-operable valves; a computer by which switch pulses of variable duration to be fed to the magnetically-operable valves are determined in dependence on the specified adjustment distance of the regulating piston; restrictors which determine the throughput of operating fluid through the magnetically-operable valves and sensors which after the switching of a respective magnetically-operable valve generate electrical signals which are fed back to the computer purely as a confirmation of operation. The restrictors are so arranged in an operating fluid circuit that, on movement of the piston, operating fluid flows through only one of the restrictors.

Abstract: A tandem master cylinder for an automobile disclosed herein includes a cylinder body having a cylinder bore, a first and a second pistons slidable in the cylinder bore and axially apart from each other, a first and a second power chambers defined, independently from each other, in the cylinder bore by the first and second pistons, and an auxiliary reservoir formed integrally with the cylinder body at its upper side adjacent the first power chamber. The auxiliary reservoir has a first and second reservoir chambers separated from each other by a partition and both connected with a main reservoir. The first power chamber is connected with the first reservoir chamber through a pair of first vent and supply ports. The second power chamber is connected with the second reservoir chamber through an oil passage which is formed in the cylinder body and which uprises in the direction from the latter to the former.

Abstract: An actuator assembly has two actuators mounted back-to-back such that their actuator rods are displaced in opposite directions. Each actuator has a spring embracing the rod between two slidable collars. The spring urges the collars apart towards stops on the rod and stops on the actuator housing, so that, on failure of the actuator, the rod is displaced to a central position. The rod is driven by a motor which also rotates two discs of different diameters. Each disc has a notch in its edge which align only at the central position of the rod and allow a roller to drop into the notch. When the actuator fails, a solenoid releases a locking arm which engages the rollers, keeping them in the notches thereby preventing rotation of the discs and displacement of the rod.