Abstract: A hydraulic shock absorber includes an enclosure member. The enclosure member has an inflow path which guides oil from the outside to the inside. The inflow path is arranged so that an axis of the inflow path deviates from a central axis of a rod.

Abstract: A shock absorber includes a first end configured to be mechanically fastened to a first component, a second end configured to be mechanically fastened to a second component, a main body, a main shaft, and a primary piston. The primary piston configured to move within the main body and further configured to provide a first damping force by movement of a fluid through the primary piston while the main shaft moves a first distance. The shock absorber also includes a deformable solid material arranged in the main body. The primary piston configured to further move within the main body and further configured to provide a second damping force by deforming the deformable solid material after the main shaft moves the first distance.

Abstract: A shock strut may comprise a strut cylinder, a strut piston operatively coupled to the strut cylinder, a shrink piston disposed at least partially within the strut cylinder, and a shrink chamber at least partially defined by the shrink piston. The shrink piston may comprise a shrink piston head, a sleeve extending from the shrink piston head, and a mechanical stop. A hydraulic fluid may be moved into the shrink chamber to compress the shrink piston and the strut piston into the strut cylinder to reduce an overall length of the shock strut.

Abstract: A gas spring for forming equipment may have a casing with an axially extending side wall, an open end, and a closed end wall with the walls defining in part a pressure chamber to receive a gas under pressure, a bearing assembly received in the casing, a piston rod slidably received in the bearing assembly for reciprocation between extended and retracted positions, a piston retainer received in the casing and separate from and normally carried by the piston rod, a deforming member in the casing adjacent its closed end wall, and configured to plastically deform the retainer when the piston rod is forced into the pressure chamber into an overtravel retracted position beyond its designed intended maximum retracted position and after such overtravel the piston rod returns to at least its extended position and the deformed retainer engages the bearing assembly and is fractured and separated from the piston rod.

Abstract: A rod assembly for spinal stabilization is provided comprising a flexible tubular element having a first end section and a second end section, an adapter connected to the second end section, the adapter having an engagement structure for connection to other rod portions or other rod assemblies of a spinal stabilization device, wherein at least a portion of the adapter extends into or onto the second end section, a longitudinal core extending through the tubular element, the core having a first end extending through at least a portion of the first end section and a second end extending into the portion of the adapter and being freely movable therein.

Abstract: A support for supporting a structure on a surface, comprising at least one support element, each support element comprising a piston, a cylinder in which the piston is moveable, and a brake for maintaining the piston in a position that is stable relative to the cylinder, wherein the piston and the cylinder are arranged so that a loading associated with the structure effects an adjustment of the support element, and wherein an increase in hydraulic pressure within the cylinder, effected by the loading associated with the structure, activates the brake.

Abstract: An air dampening assembly for an electronic device comprises a base member. A first piston housing is disposed on the base member. A second piston housing is disposed on the based member opposite the first piston housing. A sliding member is disposed between the first and second piston housing. A first piston is disposed on a first elongated member of the sliding member. The first piston housing is configured to receive the first piston. A second piston is disposed on a second elongated member of the sliding member. The second piston housing is configured to receive the second piston.

Abstract: A bellows is provided as part of a crossway between two vehicles connected to each other in an articulated manner or as a telescopic gangway, with a material web which is provided with a layer of synthetic material. The material web has a top (upper) side made of a textile and a bottom (under) side made of textile (11, 12). The spacer fibers/pile threads (13) are provided between the top side and the bottom side, such that a space between the top side and bottom side results when the material web is in a non-loaded condition.

Abstract: A roll-off piston made of plastic is for an air spring rolling-lobe flexible member (19) of the air spring. The roll-off piston (1) is configured as a plunge piston and has a preferably central support (2) for a stop buffer (3) acting in an axial direction of the air spring. The support (2) is preferably made of steel and can be received in a recess in the roll-off piston. The recess is of complementary configuration to the shape of the support and can be connected to the piston.

Abstract: Lateral support elements for engaging an associated flexible wall of an associated gas spring assembly can be displaceably mounted along an associated end member of the associated gas spring assembly, such as by way of an elastomeric mounting element. The elastomeric mounting element can be formed as an endless annular ring, from an elongated length of elastomeric material wound helically about an axis, a plurality of support element sections disposed in peripherally spaced relation to one another about an axis or from a plurality of concentric element rings formed from elastomeric and comparatively rigid materials. Gas spring assemblies including one or more of such lateral support element as well as suspension systems that includes one or more of such gas spring assemblies and methods of manufacture are also included.

Abstract: The invention relates to a diameter-variable cylindrical air pressure spring. The current air pressure spring has the shortcomings of complex structure, insufficient deformation stroke and poor ventilation effect.

Abstract: A gas spring assembly includes an unreinforced flexible wall formed from a polymeric material and an external reinforcing structure extending lengthwise along and around the periphery of the unreinforced flexible wall. The external reinforcing structure is capable of extending and collapsing together with corresponding extension and compression of the flexible wall. The gas spring assembly also includes opposing end members. The external reinforcing structure can be formed from a plurality of interconnecting wall segments that at least partially define a plurality of openings extending through the external reinforcing structure. A suspension system is also included.

Abstract: An air damper is provided which can exhibit an appropriate braking force in accordance with an input load. There is provided an air damper including: a tubular cylinder 1 in which both end portions are opened; a piston 2 which moves within the cylinder 1; and a cap 3 which closes a one-end opening of the cylinder 1, wherein the cylinder 1 has an annular seal surface 4 formed on a circumferential surface of the one-end opening, wherein the cap is mounted on the one-end opening side of the cylinder 1 so as to be moveable or deformable along an axial direction of the cylinder 1, wherein the cap is brought into contact with or separated from the seal surface 4 in accordance with a pressure change due to a movement of the piston 2 within the cylinder 1, and wherein a first orifice 14 is opened in a base plate 12 of the cap, characterized in that: a second orifice having an inlet area smaller than the first orifice is defined between the cap 3 and the cylinder 1 during an operation of the first orifice 14.

Abstract: A reinforced rubber article containing a rubber article and a fibrous layer embedded into the rubber article. The fibrous layer contains monoaxially drawn tape elements having at least a first layer, an upper surface and a lower surface. The first layer comprises a blend of polyester and nylon 6. Methods of forming the reinforced rubber article are also disclosed.

Abstract: In an oil buffer for an elevator, at least one cylindrical intermediate plunger is inserted into a base cylinder. An upper-stage plunger is inserted into the intermediate plunger. An orifice is provided in a bottom surface portion of the upper-stage plunger. A pin rod is provided upright in the base cylinder. The pin rod is inserted into the orifice in a middle of a stroke of the upper-stage plunger. A return spring causes the intermediate plunger and the upper-stage plunger to return to positions in an unloaded state.

Abstract: An apparatus may have a cylinder including a piston rod and a chamber in which a working fluid is received to resist movement of the piston rod into the chamber, and an accumulator having a first chamber in communication with the cylinder chamber to receive fluid from the cylinder chamber upon movement of the piston rod into the cylinder chamber. The apparatus may also have a pressure controller having a fluid chamber where some of the working fluid may be received and an actuator operable to increase the volume of the fluid chamber when the piston rod is retracted into the cylinder chamber to increase the total volume in which the working fluid may be received, wherein the increased volume of the fluid chamber may accommodate fluid movement in the assembly not caused by movement of the piston rod.

Abstract: A support for supporting a structure on a surface, comprising at least one support element, each support element comprising a piston, a cylinder in which the piston is moveable, and a brake for maintaining the piston in a position that is stable relative to the cylinder, wherein the piston and the cylinder are arranged so that a loading associated with the structure effects an adjustment of the support element, and wherein an increase in hydraulic pressure within the cylinder, effected by the loading associated with the structure, activates the brake.

Abstract: A fluid filled type vibration damping device wherein an outer tubular mounting member is externally fitted onto the collar sleeve at an externally fitted section formed by a tapered tube portion of the outer tubular mounting member, by means of a diameter reduction process. A mating projection projecting diametrically inward is formed on an inside peripheral face of the outer tubular mounting member, while a seal rubber layer having a thickness greater than a projecting height of the mating projection is formed covering the inside peripheral face of the outer tubular mounting member with the mating projection covered by the seal rubber layer. A location and projecting height of the mating projection are arranged so as to prevent an entry of another outer tubular mounting member into a large-diameter opening of the tapered tube portion during pre-treatment.

Abstract: An end-stop damper including a damper body in the form of a cylinder, wherein a piston is guided so that it is displaceable in the cylinder receiving chamber. An air pressure is formed in the receiving chamber produces a braking force acting on the piston during its displacement. The receiving chamber includes at least one pressure reducing opening and the piston includes a bellows section which is actively connected to the cylinder according to pressure conditions in the receiving chamber. This invention substantially simplifies the structural design of the end-stop damper because the piston and the bellows section are connected to each other so that they are formed in one piece.

Abstract: A lift assist mechanism is provided for assisting lifting of a movable component that can move between lowered and raised positions relative to a fixed structure. The lift assist mechanism includes a lift assist spring connected to a spring shaft, and an elongated track in which an end of the lift assist spring or an end of the spring shaft are movably engaged. A spring lock restrains movement of the spring shaft when a lift assist is not required, and releases the spring shaft when a lift assist is required.

Abstract: A load weighting control apparatus that suppresses deterioration of a controlled object due to impacts or the like during control, and for which energy usage costs required for control are markedly reduced, and that has a simple structure and therefore inexpensive manufacturing costs and running costs. The apparatus includes a main vacuum cylinder provided with a cylinder tube, end walls, an air vent that passes through one end wall, a valve that is provided in the air vent and serves to open/tightly close the atmosphere inside of the cylinder tube to the outside, a piston that slides back and forth within the cylinder tube, and a piston rod that is linked to the piston and passes through the other end wall and an auxiliary vacuum cylinder that includes a slacking portion where a piston rod produces slackness in the main vacuum cylinder.

Abstract: Provided is a viscous fluid-sealed damper which helps to achieve an increase in degree of freedom in terms of the selection of the material of a sealing container, which can be produced with high production efficiency, and which helps to avoid leakage of the viscous fluid. A lid member is fixed to a container main body while compressing and holding a flange portion between a sealing member and the lid member, so an opening end of the container main body can be sealed with the lid member without having to effect fixation through fusion-bonding as in the prior art, and the degree of freedom in terms of material selection can be increased. Further, if the container main body is formed of a butyl rubber, the container main body can be fixed to the lid member without using any adhesive, so it is possible to achieve a reduction in production time and in cost. Further, it is possible to avoid leakage of the viscous fluid due to defective adhesion.

Abstract: An energy absorbing device for the interior of a motor vehicle of the specification is described. The device includes two elements which are arranged movably relative to one another, having at least one actuator which is arranged between these elements and at least one receiving apparatus on the elements for fastening the actuator. The energy absorbing device is simple to manufacture and takes up a small amount of installation space, it uses a receiving apparatus shaped as a recess which is made in the elements and encloses the actuator at least partially.

Abstract: A method and apparatus for a vehicle shock absorber comprising a main damper cylinder, a first reservoir and a second reservoir. One embodiment includes a first operational mode where both reservoirs are in fluid communication with the cylinder. In a second operational mode, only one reservoir communicates with the cylinder during fluid evacuation from the cylinder. In each mode, rebound from either or both reservoirs may travel through a single, user-adjustable metering device.

Abstract: A liquid-filled vibration isolator has a first orifice channel providing communication between a pressure receiving chamber and a balancing chamber. One of the pressure receiving chamber and the balancing chamber is communicated via a second orifice channel with an intermediate liquid chamber. The second orifice channel has a shorter distance or a larger cross-sectional area than the first orifice channel. An elastic film member, such as a membrane, separates the intermediate liquid chamber and the other of the pressure receiving chamber and the balancing chamber from each other. A communicating hole of a predetermined size is formed in the elastic film member. An imaginary orifice channel combined from the two orifice channels provides a high damping effect on input vibration of relatively low frequency. As the vibration frequency increases, a gradual transition is made to the damping characteristic of the second orifice channel only.

Abstract: In a hydraulic shock absorber, a second washer, which is assembled around a lower end projection of a lower spring receiver and is retained to enlarged portions provided at the tip end of the lower end projection so that the enlarged portions are prevented from falling, is attached to a step portion of an axle bracket, and the tip end of an inner tube, which is threadedly engaged with the axle bracket, is supported by the second washer.

Abstract: An on-road energy conversion and vibration absorber apparatus receives the kinetic energy from moving vehicles and pedestrians when being weighed down, and converts the received kinetic energy into a static energy using a restorable elastic element compressing a fluid thereby storing the static energy in a pressure chamber, and then conducting the pressurized fluid to pass though a check valve along a conduit and drive a vane wheel by releasing its static energy. The vane wheel in turn drives a generator to generate electric energy, the vibration of the vehicles is alleviated by cushion effect provided by the apparatus.

Abstract: A fluid spring is provided with a sleeve, a first chamber configured to accommodate a fluid and formed in the sleeve, a hollow piston rod, a second chamber configured to accommodate the fluid and formed in the hollow piston rod, and a communicating passage configured to make the first chamber and the second chamber communicate with each other and formed in an end portion of the hollow piston rod. A part of the hollow piston rod is displacably accommodated in the first chamber. The communicating passage only permits the fluid to flow in a direction from the first chamber to the second chamber.

Abstract: A vibration transmission damping apparatus (1) is attached to a structural object (13) and supports the structural object (13). The vibration transmission damping apparatus (1) includes a cylinder (2) and a piston (3) arranged inside the cylinder (2). A space enclosed by the piston (3) and the cylinder (2) forms a fluid chamber (4) which is filled with air. The piston (3) supports the structural object (13) by pressure generated by the air. A fluid passage (7) which communicates the fluid chamber (4) with the outside is connected to the fluid chamber (4). Further, the fluid passage (7) is provided with an on-off valve (8V). The on-off valve (8V) is opened/closed at frequency of vibration whose transmission to the structural object (13) is not desirable so as to discharge the air in the fluid chamber (4) to the outside.

Abstract: A vibration suppression apparatus includes three first actuators, at least one second actuator, detectors, and a controller. The first actuators and second actuator support a structure by applying forces to the structure in the vertical direction or horizontal direction, and do not align themselves on the identical straight line. The detectors detect at least one of vibration and a position of the structure with respect to a reference position. The controller controls the forces, applied to the structure by the first actuators, based on the outputs from the detectors. The second actuator is controlled so that a force applied to the structure in the vertical direction or horizontal direction is maintained constant.

Abstract: A Fluid-filled type vibration damping device, which is configured to be free from the necessity of supplying a continuous application of electricity to a coil so as to maintain a movable valve body in either an opened state or a closed state, is provided. The device includes a cam mechanism, which transmits a rotational drive force of a motor to the movable valve body in the form of a reciprocating drive force. In the device, a first rotation angle switch is connected to a first control switch in series relative to a motor coil, and a second rotation angle switch is connected to a second control switch in parallel relative to the first switch. The first rotation angle switch is turned on in a state of a first angular range ?1, and the second rotation angle switch is turned on in a third angular range ?3. When the first control switch and the second control switch receive the same control signal, they are brought into respective inverted ON/OFF states.

Abstract: A gas spring for providing a smooth and generally gradual load distribution between interrelated parts of a press has a casing defining at least in part a gas chamber. A housing is received at least in part in the casing. The housing has a through bore sized for receipt of the piston rod therein for reciprocation between extended and retracted positions. A piston retainer is attached for conjoint movement with the piston rod. An end of the housing flexes between a compressed position when the piston retainer abuts the housing as the piston rod moves toward its extended position and an uncompressed position when the piston retainer moves toward its retracted position and out of engagement with the housing.

Abstract: A flexible wall and end structure assembly includes a flexible wall and an end structure. The flexible wall is formed from an elastomeric material and a filament structure. A bead wire is formed into an open end of the flexible wall. The end structure is received along the open end of the flexible wall and forms a substantially fluid-tight seal therewith. A portion of the filament structure is compressed between the bead wire and the end structure and extends therefrom in radially-outwardly spaced relation to said end structure. A gas spring assembly including such a flexible wall and end structure assembly is included. A method of manufacture is also included.

Abstract: A switch housing is shaped to be coupled to a gas spring and includes a limit switch having a control element which is moved to actuate the limit switch when the gas spring rod moves between first and second positions. The housing includes a cylindrical aperture for receiving the body of a gas spring with one end of the aperture including an annular wall and a coupling for attaching to the rod of a gas spring. In one embodiment the housing mounts the limit switch in offset relationship to the cylindrical aperture with the control element of the switch extending into the aperture to be actuated by the body of a gas spring.

Abstract: In a front fork in which a partition wall member is provided in an inner periphery of an inner tube, a working fluid chamber is comparted under the partition wall member and an oil reservoir chamber is comparted over the partition wall member, a main suspension spring is interposed between an upper spring bearing in a piston rod side attached to an outer tube side and a lower spring bearing in a bottom portion side of the inner tube, within the working fluid chamber of the inner tube, and a sub suspension spring is interposed between an upper spring bearing in an upper end portion side of the outer tube side and a lower spring bearing in the partition wall member provided in an inner periphery of the inner tube, within the oil reservoir chamber of the inner tube.

Abstract: An antivibration mounting apparatus (30) is provided with a case (31) fixed to a turning table (13) and a stud (33) fixed to a cab (20). An elastic body (34) is provided between the case (31) and the stud (33), and relative displacement of the stud (33) to the case (31) in the diameter direction is suppressed by the elastic body (34). On the lower part of the case (31), an attenuating mechanism (40) having an attenuating liquid (43) stored in a liquid chamber (42) and an attenuating member (41) fixed by the stud (33) is provided. Furthermore, on the upper part of the case (31), an air spring (50) supported by the stud (33) or the case (31) is provided, and a load transmitted from the cab (20) to the stud (33) in the shaft direction is supported by the air spring (50).

Abstract: A shock absorber with a shock absorber body having a cylinder. A piston is moveably guided in a receiving space of the cylinder. When the piston is moved, an air pressure generated in the receiving space exerts a braking force that acts on the piston. For air pressure reduction, the receiving space has at least one opening that produces an air-carrying connection between the receiving space and the environment. The shock absorber body has a simple design if the piston or the cylinder contains a receptacle into which an insert piece is inserted in a frictionally engaging fashion and if the opening is positioned between the insert piece and the wall of the receptacle that is touched by the insert piece.

Abstract: A pre-compressed gas strut assembly and method of installing it for use as the extension and retraction part of a folding ladder configured for installation in an opening, such as an opening in a ceiling of a house or other building. The pre-compressed gas strut has holding members attached to end caps having radial protrusions arranged on opposite ends of the gas strut that maintain the gas strut in a compressed position during installation of the attic ladder assembly.

Abstract: A crank of a shock absorber for a bicycle has two ends respectively pivotally connected with a bicycle frame and a rear shock absorber, having a round hole and a disc fitted in the round hole, a rear bearing hole, a narrow groove communicating with the round hole and the rear bearing hole, a nut at one side of the groove and a bolt extending from outside through the groove to screw with the nut, the disc having an eccentric hole; a rear shock absorber has a pivot base to face the eccentric hole for a micro-adjusting rod to extend therein stably. Then the micro-adjusting rod is rotated for an angle to alter the angle of the shock absorber relative to the bicycle frame, so a user can adjust elastic force of the shock absorber according to the capability, the body weight and road conditions.

Abstract: A method of manufacturing a gas spring including the steps of fitting and inserting a first seal member, an annular space member, a second seal member, and a rod guide, to an outer periphery of a piston rod in accordance with this order from a side of a piston, a step of providing a piston rod assembly in which a lubricant is previously injected, in an annular chamber defined among the first seal member, the space member and the second seal member, and a step of charging a pressurized gas into an inner portion of a cylinder from an opening portion of the cylinder under a sealed state, and thereafter pressing the rod guide fitted and inserted to the piston rod, thereby inserting the piston rod assembly into the inner portion of the cylinder from the opening portion of the cylinder and fixing the rod guide to the cylinder.

Abstract: An air spring assembly has a pair of spaced end plates and a flexible sleeve extending therebetween forming an internal fluid chamber. One of the end plates is a bead plate which is crimped to an open end of the sleeve. An insert having an internally threaded hole is mounted in a central hole formed in the bead plate. An externally threaded coupler having a hollow bore is mounted in a central opening formed in an end member of an auxiliary reservoir and is threadably engaged with the internally threaded hole to mount the auxiliary reservoir in an abutting relationship on the air spring bead plate to provide a variable rate air spring. A fluid path is provided through the threaded connection for the flow of fluid between the air spring and auxiliary reservoir.

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 multiple stop gas spring that has a second or stop piston assembly in addition to a metering piston assembly, connected and movable with the gas spring shaft. The stop piston assembly is preferably spaced axially from the metering piston assembly. The stop piston assembly may be utilized to stop movement of the shaft in one direction at preselected position(s) along the shaft's normal stroke, and also, or alternatively, to cause the shaft movement in the one direction to slow incrementally to a cushioned stop when the shaft approached the end of its stroke. The shaft may move in the other direction without any impediment to its movement or may stop in both directions.

Abstract: The air bellows device for use with automobiles has a bellows element as commonly understood for use in slidable engagement with for example the struts of an automobile to raise and lower the frame relative to the axles. The air pressure end plate and pressure end plate are attached to the end caps of the bellows element using five or more holes through which bolts pass to threadably engage five or more threaded holes in each end cap. In addition the gap between the strut shaft and the wall of the openings in each end plate to receive the strut shaft is sealed by the use of two O-rings.

Abstract: An annular bellows unit for replacing a vehicle suspension coil spring that encloses a shock absorber or hydraulic actuator includes annular second flange members that are sealingly connected at opposite ends of respective inner and outer bellows members to form a closed chamber, and a fill port in one of the flange members for pressurizing the chamber.

Abstract: A gas spring device includes a pressure adjustor having an actuator mechanism which regulates the rate of discharge through a pressure-release valve in equal bursts small enough to permit precise adjustment of the internal working pressure of the gas spring. Manually turning the actuator mechanism provides a consistent application of intermittent inertial force to the gas spring pressure-release valve so that resultant equal bursts provide a controlled release of pressure, even from imprecise manual operation. The chance of over-bleeding is eliminated since the mechanics of the actuator mechanism provides a single metered burst of released gas regardless of how quickly or slowly it is turned, thus the size of the burst is not dependent on the operator's skill. Because the adjustor mechanism is integrated directly into the device, it is compact and does not interfere with other surrounding mechanical structures.

Abstract: An annular bellows unit for replacing a vehicle suspension coil spring that encloses a shock absorber or hydraulic actuator includes annular second flange members that are sealingly connected at opposite ends of respective inner and outer bellows members to form a closed chamber, and a fill port in one of the flange members for pressurizing the chamber.

Abstract: A device for transferring steering responsibility from a first electro-mechanical actuator to a second electro-mechanical actuator comprises a cylinder and a first piston slideably disposed within the cylinder. A second piston is slideably disposed within an interior chamber of the first piston. A first locking sleeve is disposed within the interior chamber, a second locking sleeve is disposed within the interior chamber in opposition to the first locking sleeve, a first spring is disposed within the interior chamber interposed between the first locking sleeve and the first piston, and a second spring is disposed within the interior chamber interposed between the second locking sleeve and the first piston. The pistons and the locking sleeves also each include at least one groove disposed therein. Snap rings may be disposed within the grooves. A damping mechanism may also be incorporated into the structure of the device.

Abstract: A hydraulic lifting-lowering-system for a working table, a couch or lying furniture or another heavy object allows the height level or position to be frequently adjusted or changed. The system includes a predetermined amount of hydraulic fluid, a hydraulic fluid accumulator, the fluid pressure of which on the hydraulic fluid side is adjustable, a single acting hydraulic cylinder with two end caps, a piston pressure chamber and a piston rod which, via a piston rod sealing ring, extends sealingly out through the one end cap of the cylinder. The piston pressure chamber is pressure fluid connected to the hydraulic fluid side of the accumulator. The hydraulic cylinder is of the plunger piston type, and the cylindric tube of the hydraulic cylinder is slideably and telescopically mounted in a cylindrical guiding tube, which surrounds the piston rod in its entire length and is rigidly secured to the one end of the piston rod via a cross plate or similar construction part.

Abstract: A shock absorber is formed of a cylinder having a stopping surface, a piston slidably situated in the cylinder to be moved when it is pushed by a moving member, and a switching device attached to the cylinder to be actuated right before the piston abuts against the stopping surface of the cylinder. An electromagnetic valve is connected to the switching device. The electromagnetic valve has a first position, and a second position for allowing air in the cylinder to escape outwardly when the piston is moved and the electromagnetic valve is operated by the switching device. A spring cooperates with the piston to return the piston to a position before the switching device is operated when a pressing force applied to the piston is removed by retreat of the moving member after the switching device is actuated.