Abstract: A variable damping force shock absorber comprises a pressure cylinder forming a working chamber having first and second portions operable to store damping field. A valve is provided to control a first flow of damping fluid between said first and second portions of said working chamber during compression or rebound of the shock absorber. A bypass passageway is in fluid communication with the first and second portions of the working chamber. An angularly adjustable flow restrictor is provided for regulating a second flow of damping fluid through the bypass passageway. A pressure chamber is in fluid communication with the first (or the second portion) of the working chamber and the valve. The flow restrictor is operable to regulate also a third flow of damping fluid displaced out of the pressure chamber.

Abstract: A controllable shock absorber of the externally actuated type with greatly decreased valve response time. The shock absorber assembly utilizes valve rotation stops on the rotary valve for limiting the rotational motion of the valve. The valve is attached to a bendingly flexible control rod which is supported by a sealing and support assembly located down inside the piston rod, thus allowing easy assembly of the rotational motor by way of a bendingly alignable self-locating feature. The use of the one seal and support assembly further reduces the rotational forces needed to allow faster actuation of the valve. The valve actuation torque requirements have been further decreased by reducing the viscous drag on the valve body and reducing the inertia of the rotational valve assembly by hollowing out the valve. Performance robbing, side loading on the valve is minimized by using a at least two preferably symmetrical ports.

Abstract: A method for varying the damping force of a hydraulic damper in a vehicular suspension system includes rotatably fixing a reciprocable piston slidably mounted in a fluid-filled cylinder to the vehicular body and rotatably fixing the cylinder to a steerable wheel assembly. A variable flow fluid bypass is provided between upper and lower chambers of the cylinder. As the wheel assembly is steered, the bypass is opened and closed to vary fluid flow between the chambers and thus vary the damping force of the damper.

Abstract: A shock absorber is constructed with a hollow cylinder within which a first piston is disposed to move coaxially. A well is defined within the first piston to receive a second piston. The first piston is also provided with longitudinally extending dampening passageways and relief passageways. A cavity of variable volume filled with a compressible fluid, such as air, is defined between the two cylinders. At the start of a stroke of movement of the first piston within the cylinder, the additional length of the piston rod which enters the cylinder as the first piston moves toward the blind end of the cylinder increases pressure on the compressible fluid within the cylinder. The second piston is thereby pressed further into the first piston and ultimately closes off the dampening passageways, thereby preventing further movement of the first piston and increasing the dampening characteristics of the shock absorber.

Abstract: A miniature shock absorber including an outer tubular housing, an inner tubular housing positioned within the outer tubular housing to define a pressure chamber within the inner housing and an annular accumulator chamber between the housings, a piston mounted for movement in the inner tubular housing, and a piston rod extending out of the front end of the tubular housings for impact by an object to be decelerated. A needle valve is positioned in the rear end of the shock absorber for coaction with an axial passage defined at the rear end of the pressure chamber. The needle valve is threadably received in the rear end wall of the shock absorber and includes an external knob to threadably move the needle valve relative to the axial passage to thereby vary the resistance offered to an impacting object.

Abstract: According to an illustrative example of the invention, a gas spring comprises a cylinder which is closed at both ends thereof. A piston is provided within the cylinder and separates two working chambers within the cylinder. The working chambers are filled with a pressurized gas. The piston is connected with a piston rod which extends axially through one end of the cylinder. The working chambers can be selectively connected or separated from each other through an axial channel extending through the piston. This axial channel accommodates a valve pin. The valve pin is axially movable by an actuating rod accommodated by an axial bore of the piston rod. The piston is in sealing engagement with an inner circumferential face of the cylinder. The valve pin is in sealing engagement with the channel. The piston is provided with an elastic covering layer, which covering layer provides both the sealing engagement of the piston with the cylinder and the sealing engagement of the valve pin with the piston.

Abstract: A shock absorber of the linear deceleration type in which the housing includes a forward reduced diameter threaded portion and a fixed flange at the rear end of the housing. This arrangement combines the advantages of the primary type of shock absorber and the fixed flange type of shock absorber and allows the invention shock absorber to be mounted in a wide variety of work situations with the mounting in each situation providing a positive position of the shock absorber relative to the mounting structure so that the shock absorber may be exchanged without fear of losing the precise positioning of the shock absorber relative to the object to be decelerated and with the mounting in each situation allowing the ready provision of a stop member to accurately position the component being stopped and to assure that the shock absorber will not bottom out internally.

Abstract: A damping mechanism is disclosed for use with a displacement measuring device, such as a load cell of the type immersed in a motion damping liquid contained within a housing. The mechanism includes a shear plate adjustably supported by the housing within the damping liquid for movement towards and away from a facing surface of the load cell, which is supported for movement within a plane disposed parallel to the shear plate, for purposes of controlling the thickness of the layer of damping liquid disposed there-between. The thickness of the layer determines the damping characteristics of the mechanism.

Abstract: The invention concerns a two-way magnetic valve for controlling a bypass in a semi-active chassis. A valve slide is accommodated inside the piston of a vibration attenuator, where it slides back and forth subject to an electromagnet.

Abstract: A shock absorber wherein the piston of the piston-piston rod assembly divides the internal space of the cylinder into first and second chambers. The piston has first and second passages for the flow of fluid between the chambers in response to shifting the assembly relative to the cylinder and/or vice versa. One of these passages is controlled by a first check valve which prevents the flow of fluid through the one passage from the first chamber into the second chamber. A second check valve prevents the flow of fluid through the other passage from the second chamber into the first chamber. The piston-piston rod assembly further defines a plurality of bypasses each of which is controlled by a solenoid valve as well as by a pressure-responsive valve.

Abstract: Adjustable vibration damper for motor vehicles with a cylinder containing damping fluid, an axially-movable piston rod immersed therein, and a damping piston attached to the piston rod, which divides the cylinder into two work chambers, whereby a damping valve equipped with a valve body and a control edge controls the effective cross section of a damping passage. The valve body has an antechamber which is in communication with the upper and lower work chamber by means of at least one passage having a check valve, and that starting from the antechamber, there is a constant throttle cross section to the back side of the valve body to pressurize a control pin controlling a throttle passsage of the valve body.

Abstract: A hydraulic type vehicle height adjusting device for a vehicle shock absorber. The device has a mechanical locking means for holding relative positions before and after adjustment in vehicle height between the piston rod of the shock absorber and one of the mounting members for attaching the above absorber to the axle or the vehicle body.

Abstract: A hydraulic damper for use in a vehicle capable of adjusting a damping force in accordance with road conditions. The hydraulic damper includes a cylinder chamber divided into two chambers by a piston, a bypass passage formed in the piston for communicating the two chambers, a plurality of damping force generation valves adaped to generate the damping forces in the extension side and the contraction side strokes, and a shutter for controlling the flow passage area of the bypass passage. Rotation of the shutter permits selective switching of the damping force generation valves to provide various kinds of damping force characteristics as suitable for the road condition.

Abstract: A variable damping characteristics shock absorber includes a piezoelectric transducer which is responsive to piston stroke for producing a piston stroke indicative signal. The piston stroke indicative signal includes component indicative of piston strike direction so as to enable control of the damping characteristics depending upon the piston stroke direction.

Abstract: A hydraulic telescopic shock absorber wherein damping characteristic can be varied by means of an electromagnetic valve arrangement, the coil of which is accommodated so as to be protected against the hydraulic medium of the shock absorber. The control preferably takes place as a function of the pressure difference between the spaces above and below the piston of the shock absorber.

Abstract: An adjustable shock absorber includes a valve in the piston which has a flow path. The valve can be adjusted both rotationally and longitudinally to alter different characteristics of the flow path.

Abstract: A hydraulic shock absorber is used, for example, in a vehicle, wherein the level of damping force is adjustable in accordance with the road surface conditions or the like during operation of the vehicle. The hydraulic shock absorber includes a piston attached to one end of a piston rod and slidably fitted in a cylinder, the piston dividing the interior of the cylinder into two cylinder chambers. A passage is provided in the piston, the passage communicating with each of the two cylinder chambers. A damping force generating valve is provided at the downstream side of the passage to generate damping force. A back-pressure chamber is formed at the side of the damping force generating valve which is remote from the piston to apply pressure to the valve. A bypass passage is formed in the piston rod to provide communication between the back-pressure chamber and the upstream cylinder chamber that is provided at the upstream side of the passage.

Abstract: The fluid circuitry connecting variable volume chambers of the semiactive damper includes valve assemblies which collectively effect mechanical implementation of a preselected damper control policy that is based in part upon changes in the sign of the absolute velocity of a supported member of the system of which the damper forms a part. One of the valve assemblies has an inertial body which is connected to a movable system member but which remains substantially stationary during system operation. The inertial body and a valve member of the assembly are interconnected by a linkage which in one embodiment includes a frictional type connector, and which in another embodiment includes a dashpot.

Abstract: An adjustable fluid amplified shock absorber including a casing having a chamber, a piston rod slidable in the casing, a piston head mounted on the piston rod within the chamber, an adjustable channel located between the piston head and piston rod for providing different levels of fluid amplified flow, the adjustable channel being changed in size by axially moving the piston head relative to the piston rod by a threaded connection therebetween, and serrations on the piston head for engagement with grooves on the casing to hold the piston head against rotation while the piston rod is being turned during adjustment.

Abstract: A damper of the semi-active type is controlled such that the damping forces generated by the damper, in response to relative movement between spaced members interconnected by it, are caused to be of minimal (ideally zero) magnitude when the product of the relative displacement between the members and the relative velocity between the members is greater than zero. The foregoing control policy may be implemented by purely mechanical elements, or by electronic elements of relatively simple and inexpensive types.

Abstract: A cylinder piston apparatus according to the present invention comprises a cylinder housing having an oil chamber therein, and a rod fitted in the cylinder housing. A piston-shaped partition member is arranged in the cylinder assembly. The oil chamber is divided into first and second oil chambers by the partition member. The partition member is provided with a valve housing, which has an outside circulation hole capable of communicating with the second oil chamber. A rotary valve is fitted in the valve housing. The valve has an inside circulation hole, which is situated at a position corresponding to the outside circulation hole, and can communicate with the first oil chamber. A stepping motor for driving the rotary valve is housed in a motor-holding chamber which is defined inside the cylinder assembly. The motor-holding chamber is filled with oil, so that the motor is immersed in the oil.

Abstract: A weld gun assembly including a support structure; a pair of arm members pivotally mounted intermediate their ends on the support structure on a common pivot axis; a weld tip at one end of each arm members; an air cylinder interconnected between the other ends of the arm members and operative when actuated to move the weld tips together in a closing direction; and a pair of hydraulic control devices extending respectively between the support structure and one arm member and between the support structure and the other arm member. The control devices function to ensure that the weld tips arrive at their closed welding position adjacent the panels to be welded at the same time irrespective of unbalancing forces acting on the weld gun and further function to ensure that there are no unbalancing forces tending to move the closed tips away from their closed positions.

Abstract: A hydraulic shock absorber of the adjustable damping force type includes a piston rod which is projected out of a cylinder and provided with a damping factor adjusting actuator includes a casing. The actuator accommodating a rotor for rotation with an adjusting rod, an ultrasonic vibratory element and a vibration transmitting member. A high frequency voltage is applied to the ultrasonic vibratory element from outside to generate surface waves of a high frequency on the surface of the vibration transmitting member to rotationally drive the rotor. The rotor thus rotates the adjusting rod to adjust the damping force of the hydraulic shock absorber.

Abstract: An adjustable damping force type shock absorber having a function to detect a damping force generated thereon and a function to adjust the damping force thereof.

Abstract: Landing gear mechanism includes a restrictor assembly containing a main orifice for controlling the rate of instroke of the landing gear mechanism during landing and a taxi instroke bypass valve which provides for increased flow of hydraulic fluid within the landing gear mechanism whenever the landing gear mechanism engages a bump during taxiing to reduce the damping loads that would otherwise occur if all of the hydraulic fluid were required to flow through the main orifice. The taxi instroke bypass valve assembly includes a slide member axially movable relative to the restrictor assembly for opening and closing one or more bypass orifices in the restrictor assembly. The slide member is held in the closed position whenever the landing gear mechanism is in a specified stroke range from fully extended by a secondary piston which is acted upon by the pressure in a precharged secondary chamber urging the secondary piston into engagement with a probe connected to the slide member.

Abstract: A shock absorber for providing a linear decelerating force to a machine part by the use of a piston which forces fluid through a series of metering orifices formed by coaction of holes in the piston cylinder and internal annular grooves formed in a metering sleeve which fits over the cylinder. An infinite number of adjustments in the shock absorber characteristics are achieved by moving the grooves in the metering sleeve in orbital pattern relative to the holes in the cylinder. The annular grooves have a semicircular cross section to provide smooth flow through the metering passages and to concentrate the pressure drop in the shock absorber as turbulent flow occurring at the metering point defined by the overlap between the semicircular annular grooves and the associated holes in the cylinder.

Abstract: An air pressure shock absorber for smoothly stopping a moving object reciprocated by a rod in an air pressure cylinder. The shock absorber absorbs and reduces the internal pressure of a chamber in the cylinder to smoothly stop the moving object by the communication of air compressed in the chamber to the atmosphere through a bypass passage formed in a cylinder wall. The air pressure is released to the atmosphere after the piston has moved through a predetermined stroke.

Abstract: A variable rate shock absorber having the interior of a working cylinder divided by a piston into an upper and lower working chamber. The lower working chamber is connected to a reservoir by a bi-directional valve member. A solenoid valve housed in a hollow piston rod has an actuated state connecting the upper working chamber to the reservoir. The output of the solenoid valve is connected to the reservoir by means of an axially disposed telescoping cylinder passing through the piston and the bi-directional valve member.

Abstract: The mounting of an engine with at least one hydraulically damped spring element on the body of a motor vehicle having a wheel which is spring-mounted with respect to the body. Movements of the engine as a result of irregularities in its path are damped by a displacement transducer placed between the body and the wheel, and the hydraulically damped spring element is operatively connected to the displacement transducer in such a way that as the signal from the displacement transducer increases as a result of a change in displacement between the body and the wheel, the hydraulic damping of the spring element increases.

Abstract: An adjustable shock absorber for motor vehicles comprises a cylinder containing damping fluid, a piston rod arranged to be axially displaceable in the cylinder, and a damping piston secured to the inner end of the piston rod. The damping piston divides the cylinder chamber into two working chamber compartments and is provided with fluid flow passages which produce damping forces, the effective cross-section of these flow passages being controllable by a throttling member and an electromagnetic drive controlling the throttling member, with the electromagnetic drive including a coil winding which is mounted in the damping piston. In order to achieve improved control of the damping force the throttling member is under the influence on the one hand of the fluid pressure difference between the two working chamber compartments and on the other hand of a restoring force which is created by the electromagnetic drive.

Abstract: A hydraulic exerciser formed with a structure comprising a cylinder and an oil reservoir surrounding the cylinder and communicated therewith, a piston is slidably mounted in the cylinder, the upper end of the piston rod is protruded beyond a bearing which is supported on the upper end of the cylinder and the oil reservoir and provided with oil passages. There is a controlling mechanism provided with respect to the oil passages, which comprises a disc member has a sloped outer ring portion and an inner ring portion with a spiral contour; and a bushing member associated with the disc member and on which an oil hole is provided, with the turning of the bushing member relative to the disc member, the oil hole is covered by the spiral inner ring portion with different degrees and so that the opening thereof can be adjusted, the resistance of the oil when passing the oil hole and the oil passages thus can be varied.

Abstract: A hydraulic damping unit, particularly for use in artificial joints. The unit includes a cylinder housing having a screw-in bottom part. A hollow piston is guided in the housing and has on its jacket a shoulder which delimits with corresponding flanges on the inner wall of the housing two chambers of variable volume for storing a hydraulic liquid. A hollow throttling piston is guided in the main piston and is formed with an annular recess which communicates with respective variable volume chambers via passages passing through the jacket of the main piston at both sides of the shoulder. In the range of both passages, the bottom of the recess of the throttling piston is connected to the outer surface of the latter via a sloping annular surface which, depending on the relative position of the throttling piston to the main piston, adjusts the clearance of the passages to control the resistance to flow of the hydraulic liquid.

Abstract: Landing gear mechanism includes a built-in hydraulic actuator which may be actuated to provide a heavy load range, soft spring rate during take-off with a heavy take-off weight and a lower load range, softer spring rate after take-off and prior to landing with a lighter landing weight to yield more shock strut stroke for a given range of vertical load during landing. A special taxi valve allows for some fluid to bypass the main orifice more freely to and from the lower piston damping chamber to the shock strut air-oil chamber as soon as the landing energy stroke is complete to greatly reduce or eliminate high damping loads that might otherwise take place as the gear negotiates bumps. Such a valve may automatically be set to close for landing by the action of the gear extension during a subsquent take-off, thus reactivating the main orifice.

Abstract: A hydraulic shock absorber comprising a cylinder containing a working oil; a piston received in a slidable manner in the cylinder and formed with a communication passage for generating a damping force, a piston rod protruding from one end of the cylinder; a valve chamber formed at the other end of the cylinder in fluid communication with the inside of the cylinder; an oil tank having an oil port for communication with the valve chamber; a disc-shaped valve arranged in the valve chamber and formed with a plurality of oil holes which have different effective areas and which can selectively be brought to face the oil port which communicates with the valve chamber and oil tank when the disc-shaped valve is turned. The disc-shaped valve is preferably mounted slidably but non-rotatably upon a valve stem. A coil spring is preferably provided to urge the disc-shaped valve against the valve chamber.

Abstract: A spring load adjusting device for cushioning equipment including a pressure chamber which hydraulically controls a spring load of a coil spring.A hydraulic cylinder is hydraulically connected to the pressure chamber, a piston is slidably fitted in the cylinder, an adjust screw is provided for sliding the piston, and a protection member is provided for protecting a threaded portion of the adjust screw.The threaded portion of the adjust screw is protected from exposure to the outside and is thus protected from dust and the like, while the appearance is improved.

Abstract: A tensioner for a power transmission belt that is adapted to be operated in an endless path and a method of making the same are provided, the tensioner comprising a support unit for being fixed relative to the belt, a belt engaging unit carried by the support unit and being movable relative thereto, a mechanical spring unit operatively associated with the support unit and the belt engaging unit for urging the belt engaging unit relative to the support unit and against the belt with a force to tension the belt, and a fluid dampening unit operatively associated with the support unit and the belt engaging unit to dampen the movement of the belt engaging unit relative to the support unit in at least one direction of movement thereof with a restricting force of the dampening unit.

Abstract: When detecting means detects that changes have been achieved by an automatic transmission in lever position and/or gear position, a solenoid drive circuit is actuated for a predetermined period of time to drive shock absorbers which control the rolling of the engine of an automobile. More specifically, when it is actuated, the solenoid drive circuit energizes solenoids, whereby the rotary valves of the shock absorbers are rotated for said period. As a result, one of the two orifices of either shock absorber is closed, thus increasing the force damping the vibrations of the engine. Hence, the vibrations caused by a large torque of the engine are not transmitted to the chassis of the automobile.

Abstract: A damping force generating device for an oil damper including a hydraulic cylinder, a sub-tank having in the interior thereof an oil chamber and a gas chamber, and a first oil passage which hydraulically connects the hydraulic cylinder to the oil chamber. The damping force generating device comprises a valve seat having second and third oil passages for passing therethrough an operating oil when it is flowing in first and second directions of the first oil passage, respectively; a first valve for opening and closing the second oil passage; and a second valve for opening and closing the third oil passage. The first or second valve comprises a valve body, a mechanism for normally urging the valve body in a closing direction, and an urging force adjusting arrangement for adjusting the urging force of the urging mechanism from the exterior. The damping force generating device is simplified in structure and provides for a reduction in size of the oil damper as well as facilitated adjustment of the damping force.

Abstract: A tensioner for a power transmission belt that is adapted to be operated in an endless path and a method of making the same are provided, the tensioner comprising a support unit for being fixed relative to the belt, a belt engaging unit carried by the support unit and being movable relative thereto, a mechanical spring unit operatively associated with the support unit and the belt engaging unit for urging the belt engaging unit relative to the support unit and against the belt with a force to tension the belt, and a fluid dampening unit operatively associated with the support unit and the belt engaging unit to dampen the movement of the belt engaging unit relative to the support unit in at least one direction of movement thereof, the dampening unit comprising a piston unit and a cylinder unit having the piston unit therein and defining two chambers for fluid in the cylinder unit on opposite sides of the piston unit.

Abstract: Disclosed is a tilt cab truck having a shock absorber assembly in which a path of fluid communication between the fluid reservoir and the interior of the shock absorber assembly is automatically blocked both when the brake is applied and when a roll-angle sensing device senses a roll angle greater than a predetermined value, thereby strengthening the shock absorbing function. Two embodiments of the invention are disclosed.

Abstract: A shock absorber for providing a linear decelerating force to a machine part by means of a piston which forces fluid through a series of orifices formed by co-action of holes in the piston cylinder and holes formed in a sleeve forming a metering tube which fits over the cylinder. An infinite number of adjustments in the shock absorber characteristics is achieved by moving the holes in the metering tubes in orbital pattern relative to the holes in the cylinders.

Abstract: A tensioner for a power transmission belt that is adapted to be operated in an endless path and a method of making the same are provided, the tensioner comprising a support unit for being fixed relative to the belt, a belt engaging unit carried by the support unit and being movable relative thereto, a mechanical spring unit operatively associated with the support unit and the belt engaging unit for urging the belt engaging unit relative to the support unit and against the belt with a force to tension the belt, and a fluid operated transmitting unit operatively associated with the spring unit and the belt engaging unit for translating motion therebetween whereby the spring unit is adapted to be disposed remote from the belt engaging unit.

Abstract: A rectangular metering member with transversal grooves is located with respect to specially formed apertures in a pressure tube of a hydraulic shock absorber to form orifices communicating between the shock absorber pressure tube and a reservoir. The orifices are adjusted in size automatically to account for hydraulic fluid viscosity changes as a function of temperature by a thermal expansion plug which moves the metering member to increase or decrease the size of the orifices. The metering member is also manually positionable to adjust the size of the orifices for loads of varying mass and velocity. The specially formed apertures in the pressure tube allow the automatic temperature compensation to operate independently of the initial manual adjustment of the metering member.

Abstract: A counterbalancing mechanism for applying an upward force to the brake pedal (37) operable by the left foot of the driver of an automobile, comprising an actuator rod (66) transmitting force from a pressure-actuated diaphragm (74) to said pedal (37) to counterbalance the effective weight of the driver's left foot and leg when resting on said pedal (37), the pressure applied to said diaphragm (74) being adjustable by a pressure regulator (83) in the supply line (80, 89, 90) directing pressure against said diaphragm (74).

Abstract: An exercising device comprising a frame, actuating means, and a double acting hydraulic cylinder used therewith. The hydraulic cylinder includes a container having first and second chambers and passageways for placing the chambers in fluid communication with one another. A piston is slideably mounted within the first chamber and valve means are mounted with the container for preventing fluid communication into the first chamber when the piston is moved in a first direction and for preventing fluid communication around the piston when the piston is moved in a second direction. A piston rod extends into the container for moving the piston in response to movement of the actuating means. A control means governs the fluid flow through a selected passageway from the first to the second chamber to regulate the amount of force necessary to move the actuating means during exercise of a portion of the body.

Abstract: A hydraulic shock absorber is disclosed of the type including a piston slidably mounted in a cylinder, with a metering sleeve defining variable area orifices utilized to produce variable resistance to movement of the piston in the cylinder. The shock absorber structure includes a piston having two piece construction with head and rod components brazed together into a unitary assembly, as well as a bearing sleeve retainer for the piston rod bearing formed in three separate pieces in order to provide relatively reduced manufacturing costs of these components over one piece construction.

Abstract: A shock absorber for providing a decelerating force employs a piston disposed in a cylinder acting to displace the hydraulic fluid through a programmed series of orifices disposed along the length of the cylinder, with turbulent flow of the hydraulic fluid through the orifices. An adjustment in the shock absorber characteristics is achieved by a sleeve slidably fit over the cylinder, the cylinder having a series of ports with the sleeve being formed with a corresponding series of encircling straight-sided grooves which extend transversely with respect to the radial planes of the cylinder, such that each groove defines a variable area orifice depending on the rotative position of the sleeve over the cylinder by the overlying of the groove and cylinder ports.

Abstract: A shock absorber has a body with a bore and a secondary chamber housing a preloaded floating piston. An apertured piston and rod assembly with a float valve is retracted in the bore when the piston rod extending from the body is engaged by a moving body to be decelerated and smoothly stopped. A variable orifice head in the bore bleeds liquid through a series of passages to a return chamber which communicates with a hollow metering pin. This pin directs liquid through the piston and through outlets into a secondary chamber whose floating piston retracts against a spring as the chamber fills with liquid. This maintains a preload pressure upon the liquid in the bore and pressure chamber. The metering pin is tapered and is loosely received by the piston. When a load is axially applied to the piston rod retracting the pressure piston into the preloaded liquid within the body the liquid initially flows between the piston and metering pin.

Abstract: A door closer is connected to a door. The movements of the door cause a piston member in the door closer to pump a pressure medium through a flow duct. There is also a flow limiting member influencing at least the speed of the opening movement of the door, and this flow limiting member cooperates with an adjustable activating element which, at a desired opening moment mechanically sets the elements of the flow limiting member in a position considerably increasing the flow resistance of the pressure medium. This brakes the movement of the piston member, and thus, also the movement of the door.

Abstract: A hydraulic shock absorber having an outer tube which is closed at one end and open at the other end. An inner tube, having a plurality of metering orifices, and having a closed inner end and an open end, is mounted in the outer tube with its closed end against the closed end of the outer tube. A meter tube, having a plurality of metering openings, is rotatably mounted above the inner tube. The inner tube is retained in its longitudinal operative position by the meter tube, a rotatable retainer member, and a wave washer. A locking pin retains the inner tube against rotation. The inner tube, meter tube, and the rotatable retainer member are all assembled into the outer tube through the open end of the outer tube, and they are retained in the outer tube by a retainer member. A meter tube adjusting ring is rotatably mounted on the outer tube, and it is connected to the meter tube for adjusting the position of the metering holes in the meter tube relative to the metering orifices in the inner tube.