Abstract: A device enables the pumping of any kind of liquid while giving the liquid very high delivery pressure. The units that cause pumped liquid suction and then its delivery are driven exclusively by hydraulic means excluding mechanical means. So that there is no material contact between the driving units and the pumped product and that the product cannot damage the mechanical driving units, the chamber receiving the hydraulic fluid is, at the end of each compression cycle, placed again in direct communication with the hydraulic fluid reservoir.

Abstract: The casing of the high-pressure pump consists of two integral segments. The first segment comprises a cylindrical borehole receiving the pump shaft 5 and its ball bearings 4. The second segment 1b comprises another borehole receiving a swash plate 9 rigidly affixed to the pump shaft 5, a cylindrical core 11 with parallel sides 11a, 11b and crossed by a plurality of open-end boreholes 12 receiving the pistons 13, a second cylindrical core 16 bearing check-valves 17, and a plug 19 resting against a shoulder 18 of the second core 16 in such manner as to keep the cores 11 and 16 compressed against each other and resting against a circular stop 7 in the second segment 1b of the pump casing 1. The inner boreholes of the two segments 1a and 1b are separated by a seal 2 and the parts located in the second segment 1b are in contact with the injection gasoline.

Abstract: A hydraulic drive system for a battery operated portable compression tool. The tool has an electric motor. The drive system has a self-regulating variable displacement pump with a rotatable conduit frame having radial conduits, pistons reciprocally located in the conduits, and a ring bearing surrounding the conduit frame in an eccentric adjustable location. Ends of the pistons are located against the inside of the ring bearing. A valve plate located against a front end of the rotatable conduit frame to control entry and exit of fluid into and out of the conduit frame as it is rotated.

Abstract: A composite joint for a hydraulic system having two parts which rotate relative to each other is formed by the combination of a friction ring of hard material which is mechanically anchored to one of the relative rotating parts as a supporting collar around a ring of more flexible material mounted in a groove of the one part to exert a force on the ring of hard material providing with the joint a relatively large clearance between the two relatively rotating parts.

Abstract: Hydraulic piston pump driven in an alternating reciprocating motion by bearing, through a stud, against a cam carried by a drive shaft, characterized by the fact that a device acting as non-return feed valve is incorporated in each piston (14) while the discharge pressure is permanently re-injected into the interior of the stud (17) by which said stud (17) takes support on said cam (6).

Abstract: Hydraulic pump with axial pistons (1) in which each piston (1) forces the hydraulic liquid through a nonreturn valve, said nonreturn valves being connected to a control jack (20) by means of which the nonreturn valves can be made inactive, characterized by the fact that the nonreturn valves are placed in a chamber (10) and consist of a sliding support (15) inside of which there is disposed a spring (17) acting on an organ (16) serving as valve, which slides inside the sliding support (15), the latter being able, at will, to be coupled by any suitable means to the control jack (20).

Abstract: A rail car axle (1) carries on one of its ends a hydraulic pump (10) for energizing auxiliary devices. This pump has several pistons (11) driven by a wobble plate (12) carried on the end of a shaft (13). The car axle (1) is supported by bearings (2) placed inside a housing (3) and held in place by a cover (3a) attached to the axle end by bolts (4). The axle (1) is fastened to its undercarriage by an adaptor piece (48) attached to the housing (3). The body (16) of pump (10) is made of two parts, the first one comprising the bores (15) receiving the pistons (11) with the check valves (17) and the outlet (18), while the second part comprises the inlet (19) which opens into the chamber (20) inside which revolves the wobble plate (12). According to this invention, the second part of the pump body (16) comprises a central element (40) having a central bore containing the bearings (21) for the wobble plate shaft (13).

Abstract: A hydraulic pump comprising at least a reciprocating piston, each piston being associated with one suction valve returned to its closing position by a return spring. The return spring is associated on the one hand with the valve and on the other hand with a push-piece cyclically actuated by a cam driven by the pump driving shaft in such manner that the action of the spring on the suction valve is cancelled during the suction phase and reestablished at the end of the suction phase.

Abstract: A hydraulic accumulator comprises two-half shells, the diaphragm therebetween defining two cavities. One cavity contains pressurized gas and the cavity receives hydraulic fluid under pressure. The two-half shells are held together by a mechanical element, such as a belt which has been previously prestressed to a tension selected according to the maximum pressure to which the accumulator will be subjected. The use of the prestressed mechanical element changes the dynamic stresses ordinarily found in a hydraulic accumulator to static stresses, thus minimizing the occurrence of creeks and failure of the device.

Abstract: A hydraulic accumulator comprises two-halfs shells, the diaphragm therebetween defining two cavities. One cavity contains presssurized gas and the cavity receives hydraulic fluid under pressure. The two-half shells are held together by a mechanical element, such as a belt which has been previously prestressed to a tension selected according to the maximum pressure to which the accumulator will be subjected. The use of the prestressed mechanical element changes the dynamic stresses ordinarily found in a hydraulic accumulator to static stresses, thus minimizing the occurrence of creeks and failure of the device.

Abstract: A hydraulic pump having spring loaded valves utilizes a spring providing a constant spring force and a spring providing a varying spring force. The varying spring force depending upon the position of the pump piston. The pump suction valve opens after a variable delay relative to the beginning of the piston suction phase when the pressure prevailing in the pump's dead chamber falls below a predetermined value. Abrupt decompression to the dead chamber is therefore avoided resulting in reduced energy consumption and noise level.

Abstract: An oleopneumatic accumulator having a first chamber receiving hydraulic fluid and a second chamber receiving pressurized gas with the chamber being separated by a flexible diaphragm is disclosed. The accumulator has a cylindrical shell with two open ends closed by plugs. The plugs are held together by at least one pretensioned tie rod and one end has a larger inner diameter than the other end. When a predetermined pressure is exceeded the larger inner diameter cylinder end will separate from its plug reducing hydraulic pressure to a value less than the predetermined pressure.