Abstract: The hydraulic shock absorber includes: a first cylinder containing fluid; a piston body including extension-side oil paths permitting flow of oil along with relative movement of the piston rod in the axial direction of the first cylinder; and an extension-side damping valve configured to open and close the extension-side oil paths of the piston body. The extension-side damping valve includes: a valve plate configured to close the extension-side oil paths by covering them and open them by deforming under pressure of oil; and a preload member configured to apply a preload to the valve plate. The preload member includes: a ring-shaped portion; and axis alignment portions configured to protrude from an outer periphery of the ring-shaped portion and contact the piston body to thereby perform axis alignment.

Abstract: A damping valve includes a valve seat member, a first valve element stacked on the valve seat member, a second valve element provided between an inner circumference valve seat of the valve seat member and the first valve element, the second valve element being configured to open and close a hole of the first valve element, and a biasing member configured to bias the first valve element towards the second valve element, wherein a surface of the second valve element on an opposite side from the valve seat member is higher than the outer circumference valve seat of the valve seat member.

Abstract: A damper includes a first passage and a second passage in parallel, a first damping force generation mechanism of the first passage, a case member in which a portion of the second passage is formed, an annular disc disposed to face a bottom part in the case member to be able to be bent by a working fluid in the case member, a first chamber communicating with a first cylinder chamber and a second chamber communicating with a second cylinder chamber which are provided by the disc partitioning the inside of the case member, a first through hole provided in the bottom part of the case member to communicate with the second chamber, a bypass passage provided in parallel to the first through hole and configured to allow communication between the first chamber and the second cylinder chamber, and a second damping force generation mechanism provided in the bypass passage.

Abstract: A damping valve for a vibration damper includes a damping valve body with at least one through-channel, the outlet side of which is at least partially covered by at least one valve disk. The at least one valve disk lifts from a valve seat surface when there is an incident flow via the through-channel, and a supporting disk, as stop, limits the lift movement. An elastomer intermediate layer is arranged between the supporting disk and the valve disk. The elastomer intermediate layer is formed by an elastomer ring which has at least one raised deformation area in direction of the valve disk and/or supporting disk.

Abstract: A frequency dependent piston assembly (1) for a shock absorber comprising: a piston (10) disposed within a portion of cylinder (20), dividing volume enclosed within said portion of cylinder (20) into a first chamber (21) and a second chamber (22), said piston (10) comprising a first flow channel (111) connecting said first chamber (21) and said second chamber (22); characterized in that said piston assembly (1) further comprises: a first fluid accumulator (300); a first fluid channel (200) connecting said first fluid accumulator (300) with the side of said piston (10) closest to said first accumulator (300); a first valve assembly (100) controlling the passage of fluid (150) from said first chamber (21) to said second chamber (22), said first valve assembly (100) being configured in such a way that its preload force is controlled by said first fluid accumulator (300).

Abstract: A damping valve arrangement (1) for a vibration damper includes a damping piston (2) with a check valve, which damping piston (2) divides a cylinder (31) of the vibration damper into a first working chamber (32) and a second working chamber (33), and a control arrangement (3) with a control pot (8) and a control piston (9) which is axially movable therein. A connection channel (41) connects the first working chamber (32) to the second working chamber (33). The connection channel (41) is arranged such that it is at least partially closed by the control piston (9) during an axial displacement of the control piston (9) in direction of the damping piston (2) and opened again during an axial displacement of the control piston (9) in direction of the pot base (30).

Abstract: A control arrangement for a frequency-dependent damping valve having a control pot and an axaially displaceable control piston that axially limits a control space in the control pot and is connected to the damping valve device via an inlet connection. A spring element is arranged between the control piston and the damping valve that introduces a spring force axially into the control piston and the damping valve. When the control piston displaces towards the damping valve and the spring element increases the pressing pressure of the valve disks to increase the damping force. An axial position of a stop in the control arrangement is adjusted by plastic deformation of the pot base. A deformation portion produced by the plastic deformation and a depression partially receives the guide bush. A cross section of the depression corresponds to an outer cross section of the guide bush received in the depression.

Abstract: One embodiment discloses a pressure buffer device, which includes a pipe-shaped member that stores fluid, and a partitioning member that is movably provided in the pipe-shaped member to partition its space into a first space and a second space. The pressure buffer device further includes a fluid reservoir portion that is arranged at the a radial outer side of the pipe-shaped member to store fluid, and a communication path that is arranged at a radial outer side of the fluid reservoir portion to communicate between the first space and the second space.

Abstract: Provided is a shock absorber capable of suppressing a great change in a damping force even upon a stroke change. The shock absorber with a pilot chamber includes: a housing that constitutes the pilot chamber and includes a pilot hole and an inflow passage; a disk valve body that allows a fluid inside the pilot chamber to be discharged outside via the pilot hole; and a check valve body that allows the fluid to flow into the pilot chamber through the inflow passage.

Abstract: A vibration damper for a vehicle is provided. The vibration damper includes at least one damping cylinder made from a fiber composite material; a guiding element for guiding a piston rod of a piston movably arranged in the damping cylinder. The guiding element is located in a guiding end region at one end of the damping cylinder. A fastening element for use in attaching the at least one damping cylinder to a vehicle is located at a fastening end of the cylinder. At least one of the two end regions of the damping cylinder is conical or wedge-shaped and its element has a corresponding external form that is conical or wedge-shaped. A conical or wedge-shaped clamping sleeve located around the conical or wedge-shaped end regions of the damping cylinder.

Abstract: A circulation tool includes a tubular outer body having a main bore and at least one flow port in a wall thereof, and a valve seat assembly including a valve body, a valve member, and locking elements are movably mounted within the outer body main bore. The valve seat assembly is biased towards a first position in which flow through the outer body flow port is prevented and the locking element is in the extended position, restricting passage of the valve member along the valve body bore and out of the valve body. The valve seat assembly is movable to a second position in which the locking element is in the retracted position, permitting passage of the valve member along the body bore and out of the body. The valve seat is also movable to a third position in which flow through the outer body flow port is permitted.

Abstract: A shock absorber includes a cylinder; a piston movable therein and dividing the cylinder in first and second cylinder chambers; a cylinder attachment for attachment to a first part of a vehicle and connected to the cylinder; and a piston attachment for attachment to a second part of a vehicle and connected to the piston. The piston attachment and cylinder attachment move towards one another on an inward movement and away from one another on an outward movement. The piston includes a first inward channel; a first inward valve to open the first inward channel on inward movement; a first outward channel; a first outward valve to open the first outward channel on outward movement; a second inward channel; a second inward valve to open the second inward channel on inward movement; a second outward channel; and a second outward valve to open the second outward channel on outward movement.

Abstract: A spring for a suspension is described. The spring includes: a spring chamber divided into at least a primary portion and a secondary portion, and a fluid flow path coupled with and between the primary portion and the secondary portion. The fluid flow path includes a bypass mechanism, wherein the bypass mechanism is configured for automatically providing resistance within the fluid flow path in response to a compressed condition of the suspension.

Abstract: A shock absorber includes a push rod, a first piston, a cylinder, a piston rod, a second piston, and a third piston. The cylinder and the first piston cooperatively define a first oil cavity. The second piston, the first piston, and the cylinder cooperatively define a second oil cavity. The third piston and the cylinder cooperatively define a gas cavity. The first piston is configured to urge the hydraulic oil of the second oil cavity to flow into the first oil cavity and the third oil cavity in event the push rod is pushed. The third piston is configured to compress the gas in the gas cavity in event the third piston is urged toward the gas cavity, thereby creating a damping effect.

Abstract: A monotube shock absorber which is capable of high compression damping forces while operating at low pressure for reduced friction is disclosed. The monotube shock absorber includes a pressure tube, a piston assembly, a piston rod, a fixed valve assembly and a floating piston. A variety of methods for securing the fixed valve assembly to the pressure tube are disclosed including use of single piece pressure tubes and pressure tube assemblies. In addition, a method for assembling the monotube shock absorber including an oil filling technique is described.

Abstract: A shock absorber includes a first passage (111) or (112) and a second passage (32), (99) or (235) in communication with each other and configured to allow a working fluid to flow between two chambers (16) and (17) based on movement of a piston (15), and a passage area adjustment mechanism (101) or (236) configured to adjust a passage area of the second passage (99) or (235) depending on a position of a piston rod (18) is installed to have at least one of a maximum length-side property in which an extension-side damping force becomes soft and a compression-side damping force becomes hard in a range in which the piston rod (18) extends to an outside of a cylinder (11) farther than a maximum length-side predetermined position, and a minimum length-side property in which the extension-side damping force becomes hard and the compression-side damping force becomes soft in a range in which the piston rod (18) enters an inside of the cylinder (11) further than a minimum length side predetermined position.

Abstract: A shock absorber includes a piston assembly which includes separate flow paths. Each flow path is controlled by a valve assembly and each flow path is in parallel with the other two flow paths. One flow path will generate firm damping characteristics. A second flow path opens depending on either the frequency of the shock absorber movement or the amount of movement or stroke of the shock absorber. The third flow path includes an on/off control valve and generates a soft damping characteristic when the control valve is activated. The soft damping characteristic can be generated by a tunable bleed restriction or by a passive valve assembly.

Abstract: A vehicle suspension damper is described. The vehicle suspension damper includes: a pilot valve assembly; a primary valve; and an adjuster, wherein the pilot valve assembly meters fluid to the primary valve, and the adjuster moves the primary valve.

Abstract: A valve structure includes a piston valve assembly, and a frequency unit including a hollow housing, a free piston and an auxiliary valve assembly. The piston valve assembly, installed at one end of a piston rod, operates with the inside of a cylinder being divided into upper and lower chambers, and generates a damping force varying according to a moving speed. The frequency unit moves together with the piston valve assembly and generates a damping force varying according to a frequency. The housing is mounted at a lower end of the piston rod such that the housing is disposed under the piston valve assembly. An inner space of the housing is partitioned into upper and lower spaces by the free piston. The free piston is disposed to be vertically movable within the housing. The auxiliary valve assembly is mounted at a lower end of the housing.

Abstract: A vehicle shock absorber generates an additional counter-force acting counter to the direction of movement near the limit position of movement. The shock absorber substantially comprises a damping medium-filled damping cylinder that is divided into two damping chambers by a main piston. The main piston is axially moveable relative to the damping cylinder and is attached to a piston rod. A second piston/damping piston that contains one or more first and second through-ducts is mounted to the piston rod. The ducts are defined by first and second flow-limiting devices such as multiple thin washers. The damping piston slides in a restricting space located in the damping cylinder. The restricting space has an inside diameter smaller than the inside diameter of the damping cylinder. The additional counter-force is substantially constant throughout the entire stroke in order to create gentle braking of the damping movement.

Abstract: Shock absorber comprising a piston inside which a sleeve is present which can be operated separately from the piston. This sleeve is provided with through-flow conduits which can cooperate with apertures, which are fitted at a vertical distance, of a part of the piston in order to provide an auxiliary flow when the piston is displaced in the cylinder. Such auxiliary flow enters into a chamber which is delimited by one or more spring plates which act on a sleeve which loads the main valve against opening when it is pressed down by the spring plate. By filling the chamber with fluid, the load applied on the sleeve by the spring plate is reduced and the load on the main valve decreases, as a result of which the latter opens more readily.

Abstract: A progressive damping device for furniture is designed to prevent impacts between the mobile parts of furniture provided with self-closing systems, and provides progressive closure according to the speed and energy acquired in the closure. The damping device generally includes a cylinder in which a dynamic fluid circulates, and in the interior of which there is displaced a piston which has a rod provided with an elastoplastic valve, which delimits respective compression and expansion chambers.

Abstract: The invention relates to a hydraulic damper (1), in particular for the suspension system of a motor vehicle comprising a tube (2) filled with working liquid, inside of which a slidable piston assembly (3) is placed.

Abstract: In one embodiment, an internal bypass shock absorber is disclosed whose compression and rebound resistance can be independently adjusted and is position dependent. The shock absorber features a fluid flow regulator coupled to a hollow chamber opening of a partially hollow piston rod. The fluid flow regulator may also feature a plurality of compression orifices and rebound orifices, and a compression valve stack and rebound valve stack each having one or more deflection discs. The number, diameter, and thickness of the deflection discs of the stacks can be adjusted to independently control compression and rebound resistance by controlling the flow of fluid between the first and second chambers of the cylinder housing of the shock absorber. The shock absorber may also have a tapered needle that controls the position at which the shock exhibits its maximum resistance.

Abstract: A shock absorber has a valve assembly having a valve that is biased away from a valve body. A controlled restriction is defined between the valve and the valve body. During stroking of the piston of the shock absorber, the valve moves toward the valve body to close the restriction. The valve assembly can be used in the piston assembly, the base valve assembly or both.

Abstract: A damping valve arrangement for a vibration damper includes a damping valve body, which has at least one through-flow opening for the damping medium, and at least one valve disk which at least partly covers the through-flow openings under the influence of a closing force. The damping valve arrangement includes at least one spring element which has at least one supporting portion axially supported at another structural component part of the damping valve arrangement, and at least one spring portion disposed at a distance from the supporting portion and which introduces a spring force into the valve disk at least indirectly, wherein the spring force of the spring element is directed counter to the closing force acting on the valve disk, and wherein the spring force of the spring element is less than the closing force of the valve disk.

Abstract: A damping mechanism (1) generates a damping force in response to movement of a fluid between a first fluid chamber (R1) and a second fluid chamber (R2) of a fluid pressure shock absorber. The damping mechanism (1) comprises a partition wall member (2) that defines the first fluid chamber (R1) and the second fluid chamber (R2), and a plurality of chokes (4) provided in parallel, which penetrate the partition wall member (2) to connect the first fluid chamber (R1) and the second fluid chamber (R2). A leaf valve (8, 9) having a valve body that is constituted by only a single leaf is preferably provided in an opening portion of the chokes (4). The chokes (4) generate a damping force that is substantially commensurate with a speed of the fluid passing therethrough, and the damping mechanism (1) exhibits a linear damping force characteristic while having a simple and compact constitution.

Abstract: A valve assembly for a shock absorber includes a valve body defining a fluid passage. A valve disc engages the valve body to close the fluid passage. A fulcrum disc engages the valve disc at a first position and a second position radially outward from the first position. The fulcrum disc is designed such that the second position is closer to the valve body. In one embodiment, the fulcrum disc is concave with respect to the valve body.

Abstract: A shock absorber includes a hydraulic compression stop. The hydraulic stop includes a pressure tube surrounding the pressure tube of the shock absorber and a piston in hydraulic communication with the interior of the pressure tube. The piston can be disposed within the pressure tube and can be attached to the pressure tube or to the shock absorber. The hydraulic stop can also include a hydraulic fluid chamber and the piston can be disposed within the hydraulic fluid chamber.

Abstract: A shock absorber includes first passages configured to communicate two chambers to flow a working fluid therebetween by movement of a piston, and a second passage configured to communicate with one chamber of the two chambers. The first passages have damping valves configured to suppress a flow of the working fluid generated by movement of the piston to generate a damping force. The second passage has a variable orifice having an area adjusted by an elastic member when a piston rod moves in an extension direction, a pressure chamber installed in series with the variable orifice, and a free piston configured to vary a volume of the pressure chamber by movement of the piston.

Abstract: A shock absorber includes a piston disposed within a pressure tube. A valve assembly is attached to the piston. The valve assembly defines a first fluid flow through an always open fluid passage; a second fluid flow due to elastic deformation of a valve disc of the piston assembly; and a third fluid flow due to movement of the entire valve disc away from the piston. In one embodiment, the valve assembly is designed to be pre-assembled at an off-line and/or off-site location.

Abstract: An active suspension system for a vehicle including at least one fluid operated ram having a cylinder and a main piston mounted therein for reciprocating movement, control means for controlling an equilibrium position of the piston in the ram in response to lateral acceleration of the vehicle in order to counter the effects of body roll of the vehicle, and wherein the ram includes shock absorbing means for permitting rapid movement of the piston from the equilibrium position when operating fluid in the ram is subjected to transient increases in pressure.

Abstract: A shock absorber which facilitates an insertion/fixation operation. The shock absorber includes a spring-force application unit (84) for applying a force in a valve-closing direction to a disc valve while allowing the fixed shaft to be inserted therethrough; and a cylindrical member (47) for allowing the fixed shaft (21) to be inserted therethrough. The disc valve includes a plurality of valve discs (53) to (58). The cylindrical member is inserted into each of the valve discs (53) to (58) and the spring-force application unit (84), in which: the cylindrical member (47) is provided so as to have a radially extending gap on an inner side of the inner seat (31) of the valve main body (14).

Abstract: A fluid pressure shock absorber in which valve opening of the main valve is controlled by an inner pressure of a backpressure chamber. A first piston (3) and a second piston (4) coupled to a piston rod (10) are fitted in a cylinder (2) such that a piston chamber (2C) is defined between the first and second pistons. An extension-side main valve (18) and a compression-side main valve (23) are provided in the piston chamber (2C). Valve opening of the main valves is controlled by an extension-side backpressure chamber (19) and a compression-side backpressure chamber (24). A compression-side check valve (13) and an extension-side check valve (16) are provided at the first piston (3) and the second piston (4). During an extension stroke of the piston rod (10), the compression-side check valve (13) is closed, whereby action of a pressure of a cylinder upper chamber (2A) on the compression-side main valve (23) is prevented.

Abstract: A suspension component achieves progressive resistance via a secondary bleed valve, which functions as a support for the primary compression valve at higher displacements, in conjunction with a secondary nonlinear spring element configured to alter the force on the piston at high displacements.

Abstract: The invention relates to a method for absorbing the displacement, under the influence of an external force, of at least one plunger (10,20) in a linear electrodynamic motor comprising a least an induction coil (11, 21) magnetically coupled with the plunger. Said method comprises the steps of: detecting in said induction coil a current induced (I?ind) amplified relative to the induced current. The invention can be applied to cryogenic machines on board space ships.

Abstract: A valve (1) comprises a spring arrangement comprising a stiff (5) and a weak spring (6). The weak spring (6) has the form of a thin, circular disc having a first spring surface (6?) and a second spring surface (6?), and an inner spring part (6a) and an outer spring part (6b) substantially separated from each other with cavities (6c), yet at two points, at least, connected with legs (6d). The effect of the connection is that the outer spring part (6b) and the inner spring part (6a) can deflect in relation to each other.

Abstract: In a shock absorber of a vehicle, when a moving speed of a piston rod in relation to a cylinder tube is slow and first and second input forces are externally applied to the shock absorber, damping forces of pressure side and extension side first damping force generating devices are larger than that of pressure side and extension side second damping force generating devices. On the other hand, when the moving speed is fast, the damping forces of the pressure side and the extension side second damping force generating devices are larger than that of the pressure side and the extension side first damping force generating devices. A gas enclosure chamber filled with gas is connected to a first chamber through a free piston.

Abstract: A shock absorber for use in lowering a structure in a body of sea water. The shock absorber includes a cylinder with a piston arranged slidably therein, said piston having a piston rod which in use extends downwards out of the cylinder, wherein at least one chamber in the cylinder above the piston is fillable with a fluid and is provided with means for controlled exiting of the fluid from the chamber when the piston rod is subjected to an impact force which presses the piston inwards in the chamber. Said fluid is water deliverable from the body of sea water to said chamber through a valve device having a one-way function in the piston, and the piston and the piston rod alone have sufficient weight to pull the piston down and provide renewed filling of the chamber with water when the impact force has ceased.

Abstract: A vehicle damper of variable damping force including a cylinder, a piston and valves is disclosed. The valves have opening/closing parts and supporting parts. The opening/closing parts and the supporting parts are positioned separately so that a sufficient distance is obtained. Lengthening the distance from the supporting parts to the opening/closing parts makes it possible to reduce the opening and closing force of the opening/closing parts and to obtain highly responsive valves.

Abstract: An electronically-controlled damper arrangement includes a valve assembly. The valve assembly features a valve slide that carries at least two pistons. The first piston controls flow through two separate flow paths while the second piston controls damping provided by the valve slide. The first piston being both axially moveable and radially moveable within a valve housing.

Abstract: A hydraulic damping device includes a cylinder holding a hydraulic fluid, a piston rod moving in and out of the cylinder and having a pin at one end inside the cylinder, a rigid valve block affixed to the inner end of the pin of the piston rod and having equiangularly spaced through holes, a retainer affixed to the outer end of the pin of the piston rod, a piston coupled to the pin of the piston rod and movable along the pin between the rigid valve block and the retainer and having a plurality of axially extending through holes, a number of the through holes of the piston being respectively aimed at the through holes of the rigid valve block for allowing the hydraulic fluid to pass through the piston in one direction at a high speed during outward stroke of the piston rod and to pass through the piston in the other direction at a low speed during inward stroke of the piston, and a shock absorber that buffers the impact of the rigid valve block when the piston rod is extended out of the cylinder.

Abstract: A shock absorber (100) for suppressing vibration in a vehicle includes a valve disk (1) that delimits the interior of a cylinder (40) in which a working fluid is sealed; a first passage (2a), a second passage (2b) and a third passage (2c), which are disposed in series so as to connect pressure chambers (41, 42) delimited by the valve disk (1); a valve body (10) that selectively opens the first passage (2a) and the second passage (2b); a biasing member (15) that biases the valve body (10) in a direction for closing the first passage (2a) against the pressure in one of the pressure chambers (42); and a bypass passage (10a) that connects the first passage (2a) to the third passage (2c) when the valve body (10), having displaced in accordance with the pressure in the one pressure chamber (42) so as to open the first passage (2a), displaces further so as to close the second passage (2b).

Abstract: A hydraulic damping device for drawer includes a cylinder holding a hydraulic fluid, a piston rod moving in and out of the cylinder and having a pin at one end inside the cylinder, a rigid valve block affixed to the inner end of the pin of the piston rod and having equiangularly spaced through holes, a retainer affixed to the outer end of the pin of the piston rod, a piston coupled to the pin of the piston rod and movable along the pin between the rigid valve block and the retainer and having a plurality of axially extending through holes, a number of the through holes of the piston being respectively aimed at the through holes of the rigid valve block for allowing the hydraulic fluid to pass through the piston in one direction at a high speed during outward stroke of the piston rod and to pass through the piston in the other direction at a low speed during inward stroke of the piston and a plurality of spring strips for stopping against the rigid valve block, and a shock absorbing device that buffers the imp

Abstract: A damping force variable shock absorber is provided, which is configured to prevent a ring disc of a damping force variable valve from being excessively bent without increasing the thickness of the ring disc. The damping force variable shock absorber includes a damping force variable valve controlled in a pilot control manner by operating a solenoid. The damping force variable valve includes a disc valve and a pilot chamber provided in a housing to vary damping force. The disc valve includes a main disc, a pilot disc-S provided adjacent to the main disc in the rear thereof, and a ring disc having an outer periphery supported on a supporting portion of the housing. A spacer disc is inserted between the main disc and the pilot disc-S, the spacer disc having an outer diameter smaller than an outer diameter of an arc-shaped slot of the ring disc.

Abstract: A damping valve (10) resists a flow of fluid from a first fluid chamber (41) to a second fluid chamber (42) which are separated by a piston (1). A partitioning member (24, 27-29, 52) partitions an inflow space (A, B) of a passage (2) in the first fluid chamber (41). A spool (17, 31, 51) decreases a flow cross-sectional area of a flow path from the first fluid chamber (41) into the inflow space (A, B) according to a differential pressure between the fluid chambers. By ensuring a gap between the outer circumference of the valve disk (1) and the partitioning member (24, 27-29, 52) which permanently allows fluid to flow from the first chamber (41) into the inflow space (A, B), the damping force characteristic in a high speed region of piston displacement can be set independently of the damping force characteristic in other regions.

Abstract: A shock absorber comprising a damping cylinder is divided into a first damping chamber and a second damping chamber by a main piston device. The main piston device comprises a first main piston and a second main piston. The main pistons comprise continuous ducts that are delimited in a direction of flow by first and second flow limiters. The main pistons are mounted on a piston rod. The piston rod has an axially extending and continuous cavity through which damping medium can flow between a pressurized chamber and a respective damping chamber. The damping medium flows via an interspace delimited by the first main piston and the second main piston out into the damping chambers via pressurization ducts delimited by the first flow limiters.

Abstract: A damping force control valve, which includes a high pressure region in communication with a tension chamber of a cylinder and a low pressure region in communication with a reservoir chamber, and controls a damping force by adjusting pressure of a pilot chamber by first and second variable orifices, the first and second variable orifices having channels controlled to open or close by a spool. The damping force control valve comprises a main valve opened or closed according to pressure of the high pressure region, initial preload and pressure of the pilot chamber, the main valve allowing working fluid to flow from the high pressure region to the low pressure region when being opened; a first fixed orifice formed between the high pressure region and the first variable orifice; and a back pressure forming channel for making the first fixed orifice and the pilot chamber communicate with each other.

Abstract: A shock absorber piston has an upper half, a lower half and a tuning disc disposed between the upper and lower halves. The design for the openings in the tuning disc can be selected to individually tune the high and low speed damping characteristics in both compression and extension movements of the shock absorber.

Abstract: A hydraulic damper includes a cylinder holding a hydraulic fluid, a piston rod movable in and out of the cylinder, a rigid valve block coupled to the piston rod and having equiangularly spaced through holes, a piston coupled to the piston rod and having a plurality of axially extending through holes, a number of the through holes of the piston being respectively aimed at the through holes of the rigid valve block for allowing the hydraulic fluid to pass through the piston in one direction at a high speed during outward stroke of the piston rod and to pass through the piston in the other direction at a low speed during inward stroke of the piston and a plurality of spring strips for stopping against the rigid valve block, and a cushion block that buffers the impact of the rigid valve block when the piston rod is extended out of the cylinder.