Abstract: The fluid-tight coupling is designed for connecting a fixed hydraulic line with a rotary hydraulic line. The fixed line (1) carries on its end an axially movable tubular piston (7) provided with a hemispherical head (8); the rotary line (2) has an offset end portion (15), the axis (Y) of which is eccentric with respect to the axes (X) and (Z) of the pipes (1) and (2), this end portion (15) being also provided with a hemispherical head (16); between the two hemispherical heads (8, 16) is interposed a wobbling rotary core piece (17) formed with a central orifice (18) and with two opposed concave conical bearing surfaces for fluid-tight engagement with both hemispherical heads (8, 16) respectively. In a preferred embodiment, the axial thrust exerted on the hemispherical head (16) corresponding to the rotary pipe (2) is supported by a hydrostatic bearing (24, 25) and the rotary pipe (2) is also supported by a hydrostatic bearing (22).

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: Sealing joint for parts of hydraulic equipments in rotating relative motion, of the type consisting of the combination of a friction ring (2) of hard material having good friction resistance characteristics and of a ring (1) of flexible material, the two rings (1, 2) being anchored to one another by means of holes made in the face of the ring (2) of hard material in contact with the flexible material (1) , characterized by the fact that the holes consist of blind grooves (8) parallel to the axis of rotation, and that the ring of flexible material (1) has, integrally formed, ribs (7) having practically the same width and the same height as the grooves (8), but a shorter length (V).

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 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: 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.