Abstract: Safety valve for a hydraulic circuit supplying a hydraulic receiver having an inlet and an outlet connected to the receiver which includes between the inlet and the outlet a non-return module which has a non-return valve and a selectively operable valve having an unoperated position in which the non-return valve prevents any reverse flow of fluid from the outlet to the inlet and an operated position in which such reverse flow is made possible. A control inlet is provided for applying control pressure to the selectively operable valve. A pressure relief valve is provided between the outlet and the control inlet which is adapted to enable flow from the outlet to the control inlet from a predetermined pressure threshold.

Abstract: A hydraulic valve is adapted to be connected between a pressurized supply line and first and second lines feeding respective first and second circuits with different functions, such as the steering and braking functions of an automobile vehicle. It comprises a first control member adapted to connect the supply line to the first feed line, a two-way distributor device for the second feed line and a second control member adapted to apply to the second feed line a pressure proportional to the force exerted by the user damped by virtue of a dashpot effect.

Abstract: A valve for retaining a jack which retains a drive load. The braking valve includes a pressure reducing valve and safety valve, one of which ensures that the pressure in the chamber is retained, while the other modulates the pilot-control pressure P.sub.p. Thus, at each moment, the pilot-control pressure P.sub.p is adjusted to the value of the retaining pressure P.sub.l.

Abstract: A proportional type hydraulic distributor incorporates a distributor slide valve including a feed chamber. It is provided with a pressure compensator device for regulating the feed pressure to the feed chamber according to the output (load) pressure of the slide valve. This device includes an inlet channel, an outlet channel communicating with the feed chamber and a stator communicating with the inlet and outlet channels. A compensator slide valve slides in a housing in the stator. A spring exerts an axial force on the compensator slide valve in the same direction as the force exerted on it by the output pressure and in the opposite direction to the force exerted on it by the feed pressure. An annular obturator member on the compensator slide valve isolates the inlet and feed channels and is acted on by a return spring on the compensator slide valve. The latter has a recessed part on which the obturator member slides without clearance.

Abstract: A progressive hydraulic distributor with a slide for controlling a hydraulic actuator. The distributor has an internal load sensing passage that detects the operating pressure in the hydraulic fluid inlet or outlet passage and superimposes this pressure on the action of the spring of a feed valve. Thus, the difference between the up-flow and the down-flow of progressivity in the slide of the distributor is constant.

Abstract: A proportional hydraulic distributor with a hollow, cylindrical compensating slide, a seat at one end of the compensating slide, a reciprocable piston, an end of which is urged against the seat by a spring, a pressure assistance chamber surrounding the seat, and a choke connecting the entry pressure of the hydraulic distributor to the pressure assistance chamber. The balance of forces on the reciprocable piston and on the cylindrical compensating slide is equal to and oppositely directed with respect to the hydrodynamic drag force that develops during transitional phases of the operation of the hydraulic distributor.

Abstract: A speed limiting hydraulic slide valve. The slide valve is provided with control pressure chambers at each end thereof. The slide is provided with a longitudinal passage at each end and this passage opens into the adjacent control pressure chamber. Each passage is normally closed by a check valve. Each longitudinal passage communicates with a peripheral passage on the valve of the slide by means of a radial passage. If the hydraulic actuator, such as a cylinder, begins to move too rapidly, the pressure in the radial passage will drop, and the pressure in the appropriate control pressure chamber will thereupon overcome the check valve in the passage which opens into such chamber, and this will cause the valve slide to move in a direction which will decelerate the action of the cylinder.

Abstract: A spring return for the reciprocable slide of an hydraulic distributor. The return spring is trapped between flanges of opposed cup-shaped rings. The cup-shaped rings have conical sections which are positioned inside of the spring, but which do not contact the spring. Each cup-shaped ring has a transverse bottom, and each of the transverse bottoms surrounds the slide and contacts only a cylindrical centering section on the slide. The cylindrical centering sections on the slide are short, and each cylindrial centering section loses contact with the surrounding transverse bottom of the cup-shaped ring shortly after the slide moves relative to such cup-shaped ring.

Abstract: A hydraulic control valve whose spool slides within a stator in which gaskets are provided to insure the watertightness of the sliding motion. Due to the placement of various bores, the ports may be crossed by the gaskets without damage because the gaskets are either under balanced pressure upon crossing the ports, or under the prevailing pressure of the port which is being crossed. A watertight hydraulic slide control valve having a stator with distribution ports is positioned along the wall of a longitudinal bore. A grooved slide spool having a plurality of gaskets is positioned to slide inside the bore of the stator. When any one of the plurality of gaskets crosses a distribution port during a switching operation, the pressure acting on the gasket within the bore is less than or equal to the pressure applied to the gasket from the distribution port when the gasket passes across the distribution port.

Abstract: The body of the braking valve includes a front chamber, an intermediate chamber and a rear chamber which surround a blocking component and a governing piston. The diameter of the bore, in which slides the governing piston at the rear of the chamber, is equal to the diameter of the line along which the truncated conical bearing surface of the blocking component comes into contact with a seat situated between the front and intermediate chambers. The pressure in the intermediate chamber is connected to an outlet of a distributor which has no effect on the balance position on the blocking component.

Abstract: A hydraulic valve includes a valve body and slide, along with control pieces consisting of two thrust bearings rigidly mounted with a link which is mounted through an axial hole of the slide valve and through the axial holes of the two respective secondary pistons. The slide valve and the secondary pistons are mounted so as to provide an ample gap between the thrust bearings. The secondary pistons, located on either side of the slide valve, delineate two rear chambers which are fed with low pressure fluid. Thus, a gradual displacement of the slide valve is permitted.

Abstract: A selective and proportional hydraulic remote control device including jacks which are connected to a high pressure oil circuit commutated by distributors. The distributors are remotely controlled by a low pressure circuit which is connected to a fluid emitter. The emitter causes the input flow of the low pressure circuit for the distributors to vary. Only the input to the low pressure circuit takes place from the emitter through connections, while the return to the tank takes place from the distributors through jets, the sections of which are fixed. The same distributor can be controlled from several different locations.

Abstract: The present invention relates to a control device for a controlled non-return valve provided in large hydraulic distributors. During the mode of operation where the double acting hydraulic ram is in a non-movable state, a means is utilized to communicate a control pressure to the one-way non-return check valve to positively maintain the check valve in a closed state thereby eliminating the accidental opening of the return valve and maintaining the double acting hydraulic ram in its initial position.

Abstract: A selective and proportional hydraulic remote control device including jacks which are connected to a high pressure oil circuit commutated by distributors. The distributors are remotely controlled by a low pressure circuit which is connected to a fluid emitter. The emitter causes the input flow of the low pressure circuit for the distributors to vary. Only the input to the low pressure circuit takes place from the emitter through connections, while the return to the tank takes place from the distributors through jets, the sections of which are fixed. The same distributor can be controlled from several different locations.