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 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.

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.

Cushion holes are provided in cover members, tubular cushion rings are provided on a piston and a piston rod so as to be insertable into and withdrawable from the cushion holes as the piston moves, cushion packings capable of slidably contacting the outer circumference of the cushion rings are mounted to be movable in an axial direction, in mounting grooves formed on inner walls of the cover members constituting the cushion holes, the cushion packings each include a plurality of protrusions extending from the outer circumferential surface to the side surface near the piston and disposed circumferentially alongside one another, and cushioning grooves that extend in parallel with the axis of the cushion rings and whose cross-sectional area changes are formed on the outer circumferential surface of the cushion rings.

A pin assembly for a piston block of a hydraulic cylinder includes a pin that is axially engaged with the piston block. The pin assembly also includes a floating bush that is spaced apart from the pin to receive a sleeve therebetween. The floating bush is also configured to exhibit axial and radial play in its movement relative to the sleeve. The axial and radial play in the movement of the floating bush allows the floating bush to align with a cap port of the cylinder housing prior to entering the cap port of the cylinder housing.

A gas cylinder includes supply passages for supplying, to an accommodation chamber, a part of gas supplied to a second port. When the pressure in a first pressure chamber is equal to or lower than a prescribed pressure, a valve element closes a discharge flow passage by the biasing force of a spring member and the pressure in the accommodation chamber. When the pressure in the first pressure chamber exceeds the prescribed pressure, the valve element is moved by the pressure in the first pressure chamber, against the biasing force and the pressure in the accommodation chamber, to thereby open the discharge flow passage.

A fluid pressure cylinder is provided with a cylinder tube having a sliding hole internally; a piston unit disposed along the sliding hole so as to be capable of moving back and forth, and a piston rod projected in the axial direction from the piston unit. The piston unit can shorten the axial dimension of a piston body by mounting a wear ring to an outer circumferential section of a ring-shaped magnet attached to an outer circumferential section of the piston body.

A hydraulic cylinder for operating a work element of a work vehicle includes—a housing defining an inner volume and a piston slidably movable inside the housing in tight manner so as to divide the volume into two fluidly separated portions. The piston is connected by a rod to the work element. The housing defines two openings respectively connected to the two fluidly separated portions for allowing the passage of a fluid in pressure so as to move accordingly the piston. The hydraulic cylinder also includes a cushioning device configured to dampen the movement of piston inside the volume when it receives a sudden movement coming from the work element through the rod. The hydraulic cylinder also includes stroke variation means configured to vary the positioning of cushioning device inside the volume so as to vary a dampened stroke of piston.

A hydraulic cylinder may include a housing having a rod end and a cap end and the cap end may include a snubbing bore. The cylinder may also include a rod having a working end outside the housing and extending through a rod end of the cylinder to a piston end. The cylinder may also include a piston arranged within the housing on the piston end of the rod and configured to articulate within the housing between the rod end and the cap end. The piston may have a longitudinal bore extending into a cap side of the piston and the bore may include a retainer lip. The cylinder may also include a snubber configured for engaging the snubbing bore of the cap end when the piston approaches the cap end of the housing. The snubber may have an annular flange configured for retention by the retainer lip.

Cushion holes are provided in cover members, tubular cushion rings are provided on a piston and a piston rod so as to be insertable into and withdrawable from the cushion holes as the piston moves, cushion packings capable of slidably contacting the outer circumference of the cushion rings are mounted to be movable in an axial direction, in mounting grooves formed on inner walls of the cover members constituting the cushion holes, the cushion packings each include a plurality of protrusions extending from the outer circumferential surface to the side surface near the piston and disposed circumferentially alongside one another, and cushioning grooves that extend in parallel with the axis of the cushion rings and whose cross-sectional area changes are formed on the outer circumferential surface of the cushion rings.