Abstract: A hydraulic machine includes: a casing; a differential piston having an upper ring and a lower base, sliding reciprocally in the casing and a cylindrical housing inside the envelope, separating two chambers of the casing; a hydraulic switch conveying liquid to/from the chambers, the switch controlled by movement of the piston and including at least one rod acting on a distribution member that includes an upper valve cooperating with a first seat in the upper ring of the piston and at least one lower valve cooperating with a second seat in the lower base of the piston; and a trigger causing, at the end of the stroke, a sudden change in the position of the switch to reverse the stroke. The lower and upper valve seats accept upper and lower frustoconical portions and a lower frustoconical portion tapering in opposite directions. Also disclosed is a reversible metering pump.

Abstract: A hydraulic machine includes: a casing; a differential piston having an upper ring and a lower base, sliding reciprocally in the casing and a cylindrical housing inside the envelope, separating two chambers of the casing; a hydraulic switch conveying liquid to/from the chambers, the switch controlled by movement of the piston and including at least one rod acting on a distribution member that includes an upper valve cooperating with a first seat in the upper ring of the piston and at least one lower valve cooperating with a second seat in the lower base of the piston; and a trigger causing, at the end of the stroke, a sudden change in the position of the switch to reverse the stroke. The lower and upper valve seats accept upper and lower frustoconical portions and a lower frustoconical portion tapering in opposite directions. Also disclosed is a reversible metering pump.

Abstract: A liquid metering pump includes an intake nozzle (2) provided with an intake valve (3) communicating with a working chamber (4) in which a piston (5) can be moved in an alternating translation movement, suction being produced, with the intake valve open, when the piston moves away from the nozzle, and delivery being produced, with the intake valve closed and liquid emerging through an outlet valve, when the piston moves towards the nozzle. The pump includes, between the intake valve (3) and the working chamber (4), a device (D) for detecting the variation in pressure, the device (D) including a duct (10), which is connected at one end to the working chamber (4) and is provided at its other end with the intake valve (3), and an element (11) which is sensitive to the pressure in the duct, the element (11) being mounted in the wall of the duct.

Abstract: A liquid metering pump includes an intake nozzle (2) provided with an intake valve (3) communicating with a working chamber (4) in which a piston (5) can be moved in an alternating translation movement, suction being produced, with the intake valve open, when the piston moves away from the nozzle, and delivery being produced, with the intake valve closed and liquid emerging through an outlet valve, when the piston moves towards the nozzle. The pump includes, between the intake valve (3) and the working chamber (4), a device (D) for detecting the variation in pressure, the device (D) including a duct (10), which is connected at one end to the working chamber (4) and is provided at its other end with the intake valve (3), and an element (11) which is sensitive to the pressure in the duct, the element (11) being mounted in the wall of the duct.

Abstract: A hydraulic motor comprises a body and a piston able to slide in a reciprocating movement in a cylindrical housing of the body. A chamber (C1, C2) is formed on each side of the piston and hydraulic switching means are provided for feeding and evacuating the respective chambers (C1, C2), these switching means being able to adopt two stable positions. Control means (H) having elastic means for abruptly bringing about changes in the position of the switching means are included. There are triggering means (13, 15) able, at the end of the stroke of the piston (9), to bring about the change in position of the switching means (G). The piston (9) has a closed cross section and the switching means (G) are arranged in the body (1) of the machine, redially on the outside of the cylindrical housing (7) in which the piston (9) slides.

Abstract: The invention concerns a hydraulic machine, in particular a hydraulic motor, comprising: a body (1), a piston (9) adapted to slide in reciprocating motion in a cylindrical housing (7) of the body, a chamber (C1, C2) being formed on either side of the piston, hydraulic switching means for feeding and evacuating the respective chambers (C1, C2), control means (H) for abrupt change of the position of the switching means, and triggering means (13, 15) for, at the end of the stroke of the piston (9), changing the position of the switching means. The piston (9) is a single acting and non-differential piston, having a closed cross-section and the switching means are arranged in the body (1) of the machine, radially outside the cylindrical housing (7) wherein slides the piston (9).