One or more components of a high pressure pump include a hydraulic surge dampener. The hydraulic surge dampener mitigates or prevents damage that results from a sudden pressure surge that results from impact of components, for example a hydraulic piston and a hydraulic head, of the high pressure pump. The hydraulic surge dampener may include one or more grooves, one or more through holes, or a combination thereof. The hydraulic surge dampener may be carried by or be part of one or more components of the high pressure pump, such as the hydraulic piston, the hydraulic head, or both.

In a cushion mechanism of a gas cylinder, when the pressure of a gas in a first pressure chamber is less than or equal to a prescribed pressure, a valve body cuts off communication between the upstream side and downstream side of a discharge flow passage by mean of the biasing force of a spring member. In addition, when the pressure of the gas exceeds the prescribed pressure, the valve body is displaced to the downstream side of the discharge flow passage against the biasing force, thereby enabling communication between the upstream side and the downstream side of the discharge flow passage.

A spool valve for controlling the flow of a fluid into a reciprocating piston cylinder. A spool is slideably inserted into an outer casing, the spool valve having a first and a second non-waisted end portions and having a waisted middle portion. The casing has an intake port and output port for fluids entering and exiting the casing. A first non-waisted end portion covers the intake port during a first valve-closed event as the spool slides in one direction within the casing. The waisted middle portion is sufficiently wide to uncover both the intake port and the output port during a valve-open event as the spool slides in one direction within the casing. A second non-waisted end portion covers the output port during a second valve-closed event as the spool slides in the same one direction within the casing.

A hydraulic buffer pertains to the field of hydraulic parts. A signal device (X) is installed at a position close to an end of a cylinder stroke to control movement of slide valves (12, 18, 12a, 12b, 12c, 12d, 12e, 12f, F1, F2, F3, F4) of the hydraulic buffer, to dynamically adjust the degree of valve openness and a liquid flow direction of a buffering module (Y), and therefore control pressure of oil entering an oil returning chamber of a cylinder. The high-pressure chamber of the cylinder releases pressure and unloads, and/or the oil returning chamber throttles to load pressure, such that a moving speed of a cylinder piston (6) at the end of the stroke is controlled, realizing buffering of the cylinder. The device eliminates defects in the prior art in which a buffering mechanism of a cylinder is complex, manufacturing accuracy requirements are high, structural arrangement is difficult, it is difficult to employ a combined configuration in which an oil returning chamber throttles to load pressure and a high-pressure chamber releases pressure and unloads, and buffering efficiency is not high. The device has desirable buffering controllability and high reliability, such that the overall quality is improved.

A hydraulic assembly includes a barrel having a head port disposed proximate an end of the barrel, a piston assembly disposed within the barrel and movable relative thereto, the piston assembly including a bore terminating at a back wall, the bore defining a longitudinal axis, and a plunger at least partially received within the bore and translatable along the longitudinal axis. The plunger includes a main body having an end facing the head port, a shoulder extending radially-outwardly from the main body, and a passageway extending through the main body. A spring is disposed in a first region defined between the shoulder and the back wall, the spring configured to exert a biasing force on the shoulder.

In an interior of a cylinder tube of a fluid pressure cylinder, a piston unit is provided, which is displaced along an axial direction under the supply of a pressure fluid. The piston unit includes a disk shaped plate body, which is connected to one end of a piston rod, and a ring body connected to an outer edge portion of the plate body. The plate body is connected to the piston rod by plural second rivets, which are punched in an axial direction with respect to the piston rod.

A steam reciprocating piston engine that uses a pressurized working fluid to drive first and second pistons in reciprocating power strokes is disclosed. A piston is configured for reciprocating motion within the cylinder and traverses between bottom dead center and top dead center positions. An uppermost stop is reached wherein the working fluid is allowed to escape the cylinder through one or more exhaust ports whereby the fluid travels through a closed loop circuit ultimately directing pressurized fluid back into the cylinder inlet. Momentum causes a spring connected mass to continue upward maintaining the piston above the exhaust port so as to allow escape of the working fluid. Return of the piston and mass is caused by opposite movement of a second piston whereby another stroke is initiated. Power output may be transferred to any suitable system.

A hydraulic piston-cylinder group includes a cylinder containing a piston which defines internally of the cylinder at least a first and a second chamber, respectively communicating with a first and a second inlet/outlet hole of a pressurized fluid for actuating the piston between a first and a second position. The piston has a gully defined by a bottom wall, a first lateral wall that is proximal to the first free end, and a second lateral wall distal relative to the first free end, the first and second lateral walls serving as first and second abutments for the piston ring, the gully communicating through at least a passage with the first chamber. A depression is provided on the contact surface between the second lateral wall of the gully and the piston ring, the depression enables a controlled bleeding of the pressurized fluid between the piston ring and the second lateral wall.

A pressure-medium cylinder does not have a component that dynamically seals the piston rod and can be well-cleaned safely from outside. The pressure-medium cylinder includes a cylinder housing, a piston, a piston rod, and a static end-position seal. The piston is axially movably disposed in the cylinder housing. The piston rod is connected to the piston and penetrates the cylinder housing toward an end face through an outlet opening. The piston rod has a stop surface extending radially from the piston rod in a piston rod portion disposed outside of the cylinder housing. The stop surface contacts the cylinder housing in an end position during retracting of the piston rod and thus sealingly covers and/or extends around a gap region or gap regions between the piston rod and an edge of the outlet opening.

A steering system for an articulated truck. The articulated truck is formed of a tractor and a trailer and an articulation joint. The steering system includes a hydraulic cylinder, with a cylinder barrel and a piston. The steering system provides for changes in angle between the tractor and the trailer. The hydraulic cylinder includes a snubbing tube projecting into the cylinder barrel. A hydraulic fluid passage opens into the cylinder barrel within the snubbing tube. The snubbing tube includes a main slot and a plurality of channels each extending between an interior and an exterior of the snubbing tube. The plurality of channels have a cross sectional area smaller than a cross sectional area of the main slot. When the articulated truck is steered, the piston moves in the cylinder barrel and the snubbing tube dampens the movement to prevent forces generated by the piston damaging the articulated truck.