Abstract: A gas spring includes an outer tube; a base plate; a head plate; an inner tube mounted to extend between the head plate and the base plate; a piston/rod assembly mounted to reciprocate vertically in the inner tube between a retracted, compressed position and an extended, rest position; a valve ring coaxially mounted around the rod to reciprocate between the main piston and head plate; a primary gas chamber; a relief chamber; seals for preventing fluid flow from the primary and relief chambers; a passageway providing communication between the primary gas chamber and relief chamber; and, valve apparatus for controlling fluid flow between the primary and relief chambers. The valve apparatus operates to open and close the fluid flow as a function of the position and direction of travel of the piston/rod assembly.

Abstract: A gas shock absorber has a pressure tube which defines a working chamber. A piston divides the working chamber into an upper working chamber and a lower working chamber. A series of extension passages extend through the piston and are opened and closed by an extension valve assembly. A first and a second series of compression passages extend through the piston and are opened and closed by a first and a second compression valve assembly, respectively. A rod guide assembly is located between the pressure tube and a piston rod. The rod guide assembly includes an oil chamber for sealing and lubricating the piston rod.

Abstract: A two-stage shock absorber has a pressure tube within which a valve assembly is slidably disposed. A piston rod is attached to the valve assembly and extends out of the pressure tube. A ring is slidably disposed within the pressure tube and engages the valve assembly. After a specified amount of movement of the valve assembly with respect to the pressure tube in an extension movement of the shock absorber, the sleeve engages a metered slot and reduces the fluid flow through the valve assembly to progressively switch the shock absorber from soft damping to firm damping.

Abstract: A pilot chamber is formed at the back of a disk valve for each of the fluid flow systems for the extension and compression strokes. Damping force in a low piston speed region is controlled with a pressure control valve. The valve opening pressure of the disk valve is controlled by varying a pilot pressure introduced into the pilot chamber from a cylinder's hydraulic fluid chamber through a cut portion in a piston bolt and an orifice groove formed in a fixed member supporting the disk valve, thereby controlling damping force in a high piston speed region. A sharp pressure change occurring when the stroke direction of a piston rod changes is attenuated by the restricting action of the orifice groove so as not to be readily transmittable to the pilot chamber. Accordingly, it is possible to suppress a change in damping force due to the sharp pressure change and hence possible to obtain stable damping force.

Abstract: The present invention is directed to shock absorbers, including position-sensitive shock absorbers (2) in which the position-sensitive damping can be different during compression and rebound strokes, and shock absorbers (60) with damping adjusters (80, 118) which vary the damping provided during compression and rebound strokes. The position-sensitive shock absorber includes a cylinder (4) within which a piston (122) is movably mounted for movement between the first and second ends of the cylinder. Bypass openings (24-32) open into the cylinder interior (6) at axially spaced-apart positions. The bypass openings are coupled by a bypass channel (38). A flow valve (40, 42) may be positioned along the bypass channel permitting fluid flow from the first opening to the second opening and restricting fluid flow from the second opening to the first opening.

Abstract: In a damping force generator for a hydraulic damper, the valve is protected from pressure rise in the damper and its durability is thereby enhanced. The damping force characteristics can be vary in stepwise fashion by providing a main leaf valve 21 and a sub-leaf valve which closes an opening 21A formed in the main leaf valve 21, and the approximate mid-point of the main leaf valve 21 is supported by a plurality of intermediate seat surfaces 16 from the side of a port 13. The outer circumference of a main leaf valve 64 is supported by an outer circumferential seat surface 62, and the outer circumference of a sub-leaf valve 65 extends outwards to the vicinity of a part where the outer circumference of the main leaf valve 64 and the outer circumferential seat surface 62 overlap.

Abstract: A hydraulic shock absorber (10) is composed of a piston (3) that partitions the inside of a cylinder (1) into an extension side chamber (R1) and a compression side chamber (R2), a throttler (3c) for connecting the extension side chamber (R1) and the compression side chamber (R2), a piston rod (2) that extends from the cylinder (1) interlocking with the piston (3), an accumulator (11) that allows entrance and exit of a volume of hydraulic operating fluid equivalent to the volume of a portion of the piston rod (2) entered within the cylinder (1), and a spring (8) that pushes the piston (3) against the piston rod (2).

Abstract: Damping-valve body, in particular for a piston-cylinder unit filled with damping fluid, having separate passages for two directions of flow, at least some of the passages having an outlet opening that is at least partially covered by at least one valve disk. Each passage has a rib that extends radially, relative to a first direction of flow of the damping fluid, from a boundary wall of the passage and bears a valve support surface for the at least one valve disk.

Abstract: A shock absorber has a pressure tube with a piston assembly slidably disposed within the pressure tube and attached to a piston rod. The piston assembly divides the pressure tube into an upper working chamber and a lower working chamber. The piston assembly includes a compression and a rebound valve assembly. The piston assembly also includes a housing attached to the piston rod within which is slidably disposed a piston to define a closed chamber. The closed chamber is in communication with one of the working chambers through a passageway extending through the piston rod. The housing and piston provide two stage damping in rebound and compression with a smooth transition between soft and firm damping.

Abstract: Shock absorber including a cylinder body and a piston cooperating to two chambers one and the other of which respectively function as high-pressure and low-pressure chambers, a piston rod fixed to the piston, and a damping force control device including (i) a hard valve which permits a flow of a working fluid from the high-pressure chamber toward the low-pressure chamber when a difference between fluid pressures in the high-pressure and low-pressure chambers is larger than a predetermined threshold, (ii) a soft valve which permits the fluid flow from the high-pressure chamber toward the low-pressure chamber when the pressure difference is not larger than the threshold, and (iii) a flow restricting fluid passage disposed in parallel with at least one of the hard and soft valves, and wherein at least one of the hard and soft valves and the soft valve permits a flow of the fluid therethrough during both elongation and contraction of the shock absorber.

Abstract: A speed controlling hydraulic dampener comprises a tubular housing defining a closed cylindrical chamber for containing a hydraulic fluid. The chamber containing two separate pistons and piston rods that extend through sealed openings in the ends of the housing. The second piston is spring-biased. First and second orifices are provided in the wall of the housing which are connected by a tubular passageway. A special seal arrangement cooperates with the first piston rod and with the wall of the housing defining the cylindrical chamber. This seal includes a third orifice extending longitudinally therethrough and cooperating with this orifice is a flow-controlling needle valve that can be used to adjust the rate of flow of hydraulic fluid from a first portion of the chamber through the first orifice, the tubular passageway and the second orifice to a zone between the first and second pistons.

Abstract: A piston-type rail retarder includes a shock absorber having a cylinder defining a cavity between a pair of end walls. A piston rod extends axially through one of the end walls, and a piston is mounted on the piston rod between the end walls so as to divide the cavity into first and second working chambers containing a damping fluid. A first array of passages extends through the piston and communicates between the first and second chambers, and a sprung valve assembly is provided for obturating the first array of passages in the event of the velocity of the piston rod relative to the cylinder exceeding a predetermined value. The first valve mechanism includes a valve plate and a spring for biasing the valve plate into an open position. An array of restricted orifices extend through the valve plate and communicate directly with the corresponding array of first passages when the valve plate is closed.

Abstract: A piston-cylinder unit, comprising a cylinder which is subdivided by a piston on a piston rod into two working chambers. Between the two working chambers, there is a fluid connection which can be blocked by means of a valve arrangement having at least two individual closing valves arranged in series, each with a valve inflow side and a valve outflow side. The valves open sequentially. In the flow path between the individual valves, there is a throttle arrangement which produces a pressure reduction between the valve outflow side of the first closing valve towards the valve inflow side of the following closing valve. As the opening of the first closing valve increases, the effect of the throttle arrangement decreases; to the same extent, the pressurization increases on the valve inflow side of the following closing valve. The valve arrangement features two flow-through directions and is made so that each can be blocked.