Abstract: A damping apparatus for damping vibrations in a vibrating system including a piston which is reciprocally movable in a fluid filled chamber, piston movement in either direction of movement being resisted by fluid pressure in the chamber behind the piston, which resistance provides damping forces which act to oppose piston movement, the piston being connected to one component of the vibrating system and the chamber being connected to a second component of the vibrating system, characterised in that structure is provided to relieve the fluid pressure behind the piston to allow substantially unopposed piston movement in the chamber without damping forces being provided, during piston movements which occur in response to vibrations in the vibrating system at frequencies other than a fundamental frequency which the damping apparatus primarily is intended to damp.

Abstract: A device and method 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 vehicle and vehicle suspension including a number of shock chambers to provide different levels of incrementally increasing shock absorption/cushioning. The suspension includes a shock tube having a first end and a second end; a first member telescopically receiving the first end of the shock tube; a first piston coupled to the first member and sealingly received in the first end of the shock tube; a second member telescopically receiving the second end of the shock tube; and a second piston coupled to the second member and sealingly received in the second end of the shock tube. The first and second pistons form at least one shock tube sealed chamber in the shock tube, and the first member and second member are distanced from one another by the shock tube.

Abstract: A monotube damper and suspension spring assembly for a motor vehicle includes a tubular housing defining a chamber filled with damping fluid. A piston and piston rod reciprocate within the chamber. In order to compensate for volumetric changes of the chamber due to extension and retraction of the piston rod within the chamber, either the upper seal cover or lower bottom ring assembly is slidable within the housing. A preload is applied either to the housing or to the seal cover to thereby bias these elements to compensate for volumetric changes in the chamber.

Abstract: A vibration damping system for absorbing shock loads includes a hydraulic damper containing a piston slidably reciprocating within an oil filled chamber and dividing the chamber into a pair of subchambers. A hydraulic motor is in fluid communication with and located between the subchambers and is controlled by a field responsive fluid, such as an electrorheological (ER) actuated device. The hydraulic motor transforms fluid motion into rotating motion by a pair of meshing gears. The ER device is a flow cell and is connected to a shaft of one or both of the meshing gears. The magnitude of an electric field applied to the ER fluid controls the flow rate of the hydraulic fluid passing through the hydraulic motor by controlling the resistive force to the rotary motion of the gears. A plurality of check valves controls the direction of flow of the hydraulic fluid between the hydraulic motor and the subchambers.

Abstract: An air damper suitably used in the glove box of an automobile comprises a cylinder having a first open end and a second end, a guide cap covering the first open end, and a piston movable in the cylinder. A compression coil spring is inserted in the cylinder between the piston and the guide cap. The coil spring forces the piston toward the second end of the cylinder in the free state. The piston has a hook piece, which is threaded with a spring. At least one end of the spring is taken out of the cylinder via the guide cap, and connected to the glove box. The guide cap has a stopper means projecting inside the coil spring and toward the piston. If the glove box is opened and the string is pulled out of the cylinder, the piston moves toward the guide cap. The piston then strikes the stopper means of the guide cap before the coil spring is fully compressed.

Abstract: The present invention is a motorcycle suspension fork that combines a presently available conventional suspension with a presently available inverted suspension. The suspension of the present invention has two telescoping segments, with each segment capable of moving independently from the other. This design allows one segment to compress to absorb a shock while allowing the other segment to expand in preparation of absorbing another shock, thus allowing better shock absorption and a more comfortable ride.

Abstract: Power shovels include a dipper door which must be held shut to retain a load of material within a dipper and which must be allowed to open to discharge the load of material from the dipper. Such dipper doors are extremely heavy and, as a result, the opening and closing of the dipper doors must be dampened in order to prevent the dipper doors from banging against other components of the power shovels. There is provided a hydraulic assembly which is mounted to a dipper body and a dipper door of a dipper of a power shovel. The hydraulic assembly includes a restricted flow conduit to prevent unrestricted flow of hydraulic fluid between fluid chambers of the hydraulic assembly. Accordingly, as the dipper door opens or closes, as the hydraulic fluid moves from one chamber of the hydraulic assembly to the other, the restricted movement of the fluid causes the dipper door to open or close in a controlled manner thereby dampening the effect of movement of the dipper door.

Abstract: A damper including a cylinder, opposite end walls in the cylinder, an elongated shaft mounted for axial movement in seals in the end walls, a piston head on the shaft between the end walls, fluid-tight bellows mounted in sealed relationship between the shaft and the end walls, fluid in the cylinder and in the bellows, and flexible washers mounted between the shaft and the end walls for maintaining the shaft centered in the seals. The damper can function as a snubber when it utilizes a valved piston head.

Abstract: A vibration control system is provided for an appendage such as an antenna 10 coupled to a platform such as a spacecraft 12. The antenna 10 is coupled at a base 14 so as to extend from the spacecraft 12. A plurality of guidelines 20 extend between remote portions 22 of the antenna 10 and the antenna base 14. A plurality of motion control elements 36 are provided within the antenna structure for reducing oscillation settling time of the antenna 10 relative to the spacecraft 12. The motion control elements 36 include a material disposed therein having its damping response changed according to the magnitude of an electric or magnetic field applied thereto.

Abstract: A damping system having a lightweight, low-cost, thin-walled cartridge body sealed on both ends by mechanically deforming the cartridge body wall into sealing elements that seal the ends of the cartridge body. Preferably, the cartridge body wall is roll crimped to compress the sealing elements and thereby create a seal between the wall and the sealing elements. The cartridge body is preferably also provided with a retaining ring having an internally formed ridge that engages the mechanically deformed portion of the cartridge body wall. The retaining ring is thereby axially fixed with respect to the cartridge body. Because the retaining ring is positioned about the cartridge body, the retaining ring forms a shoulder with respect thereto. The shoulder thereby formed may be inserted within the recess of a bicycle suspension fork strut to fix the damping cartridge therein against movement.

Abstract: A cushioned braking system for cushioning the impact of a moving vehicle for amusement for children is disclosed. The braking system comprises a double ended air cylinder having a first cylinder end and a second cylinder end. A first head member and a second head member close the first and second cylinder ends, respectively. A first piston rod extends axially outward from the cylinder through the first head member. A first piston is on the first piston rod within the cylinder. A second piston rod extends axially outward from the cylinder through the second head member. A second piston is on the second piston rod within the cylinder. A spring assembly resiliently connects the first piston to the second piston within the cylinder. The spring assembly serves to bias the first and second pistons toward a reference position. The cylinder also has a vent for controlling air flow within the cylinder.

Abstract: A damping mounting structure for use between two members for isolating motion changes which incorporates a plurality of dampers connected between the two members in a closed geometric shape and which uses cross connections between the dampers located on opposite sides of the geometric shape so that translation motion between the two members is damped less than rotational motion between the two members and an accumulator to provide pressurization of the system but to prevent loss of pressure due to slow rotational vibrations, one-way valves are connected between the system and the accumulator to allow fluid flow only from the accumulator to the system and not from the system to the accumulator and pressure relief or burp valves are used to allow short duration fluid flow from system back to the accumulator when a predetermined system over-pressure is exceeded.

Abstract: A damping mounting structure for use between two members for isolating motion changes which incorporates a plurality of dampers connected between the two members in a closed geometric shape and which uses cross connections between the dampers located on opposite sides of the geometric shape so that translation motion between the two members is less stiff than rotational motion between the two members.

Abstract: A shock absorbing system wherein arrangements are provided for altering the hysteresis effects of the fluid utilized so as to obtain desired damping curves. Particularly, by employing different hysteresis effects it is possible to obtain larger damping forces at the end of the piston stroke. The hysteresis effect can be altered by changing the effective area of the shock absorber piston by controlling the flow paths between the piston chambers and an accumulator chamber and the pressures necessary to open these flow paths. In addition, by employing selectively openable variable volume chambers and variable pressure accumulator chambers, further changes in the hysteresis effect can be accomplished.

Abstract: A damper variably moderates movement of a piston on a rod in a cylinder filled with highly pressurized elastomeric gum. An axial bore through the piston allows relative ease of movement when a relatively low force is applied to a rod driving the cylinder. A high stress or acceleration on the rod forces a steel washer carried on the cylinder to deform and block the bore. The stiffness of the washer is proportioned to the ability of the clearance of the piston in the cylinder and the pressure and stiffness of the gum to establish a threshold. Damping is provided according to a preselected function, namely low initial resistance, and sharp increase is resistance to movement of the piston in response to stress exceeding the threshold. This function is suitable for damping in such applications as earthquake protection for structures and high stress protection for railroad beds.

Abstract: A damping mounting structure for use between two members for isolating motion changes which incorporates a plurality of dampers connected between the two members with spring members operating in parallel with the dampers to provide stiffness and where the springs are pneumatic to provide proper stiffness when the load is heavy without damage to the springs and/or to provide variable stiffness when desired.

Abstract: A universal stabilizer strut for a truck camper includes a hydraulic unit that is made in only one standard length and one or more interchangeable extension units, so that different designs of cabs with different heights and widths can be accommodated. Each end of the stabilizer strut is provided with a spherical mount that accommodates angular deviations between the strut and its attachment to the truck and to the camper. One end of the stabilizer strut is secured to an upper bracket extending downwardly and forwardly from a lower surface of the cabover portion of the camper and the other end of the stabilizer strut is secured to a lower bracket expending upwardly and rearwardly from the front bulkhead region of the truck chassis, with the two ends of the stabilizer strut being adapted to be quickly installed and removed from the two respective brackets.

Abstract: Disclosed is an improved connection between the forwardly-positioned towing-vehicle and the tow-bar (for a towed-vehicle behind a rearward-mount of the towing-vehicle) such connection can for certain purposes can eliminate a "ball"-type connection in favor of a pivotal-pin-type connection; and, for the forward-tube of such tow-bar, is internally provideable with strategically-located helical-spring and manually-accessible adjusting-nut together functionable to guard the towed-vehicles' brakes from overheating during extremely downwardly-inclined roadway conditions.

Abstract: The present invention relates to a high pressure servo-mechanism to be installed in a civil or architectural structure to alleviate dynamic reaction of the protected structure and to prevent the possible damages to the structure by earthquakes or typhoons thus assuring the security of human lives and properties inside the structure.

Abstract: A double acting center-of-car cushioning device mounted in the sliding sill of a rail car includes two pistons and rods, two pressure cylinders and mirror image sets of flow orifices in the pressure cylinders. The piston rods extend out from ends of the pressure cylinders and engage a fixed sill of the rail car. Movement of the pistons within the pressure cylinders forces fluid through the flow orifices resulting in efficient dampening.

Abstract: A shock absorber for a vehicle includes telescoping cylinder and piston assemblies, with the piston assembly including two pistons connected by a piston shaft which passes through a transverse headwall in the cylinder. Fluid flow from one side of the headwall to the other is restricted by ports in the headwall and, in an alternative embodiment, by external flutes in the piston shaft. The piston and cylinder may be spring loaded with an external coil suspension spring, or may be biased toward an extended position by a pressurized internal gas reservoir. The dual piston design of the shock absorber eliminates the need for a separate gas reservoir, either within the shock absorber or external to the shock absorber, while also obtaining an efficiency of design by stabilizing the piston against rocking loads without the need for a separate piston rod seal.

Abstract: A snubber is disclosed for use on an airplane translating door hinge arm (13) comprising a hydraulic device (41) and a flow regulation system (40). The hinge arm (13) includes sprockets (25, 27) placed at the ends (15, 17) of the hinge arm (13). Roller chain pieces (31) rotate partially about the sprockets (25, 27). A pneumatic actuator (33) having a through-rod (37) and housing (35) is located on one side of the hinge arm (13). The actuator housing (35) is supported by a support member (23) integral with the hinge arm (13). The ends of the actuator through-rod (43) are each coupled to first ends of each of the roller chain pieces (31). The hydraulic device (41) comprising a housing (47), a through-rod (43), a piston 45, a first compartment (49), a second compartment (51), and hydraulic fluid, is also supported by the support member (23). The ends of the hydraulic device through-rod (43) are each coupled to second ends of each of the roller chain pieces (31).

Abstract: Snubbers are useful in dampening inertia loads at the end of stroke movement of a hydraulic motor. Known snubbers usually have a spear type annular orifice with an associated plunger which usually restrict fluid flow in the non-snubbing mode thereby slowing response in the opposite direction. The subject snubber includes a snubber stem which is moved to contact the end of a tubular hydraulic cylinder so that all fluid from an actuating chamber must pass through a circular orifice which will build up pressure in the actuating chamber to provide a dampening effect on a piston rod assembly. When fluid is directed into the actuating chamber the snubber stem will move away from the end of the tubular hydraulic cylinder to allow free flow into the actuating chamber to provide quick response for extension of the piston rod assembly.

Abstract: A method and apparatus for controlling relative movement such as rotary movement between a railway truck and a car body supported thereby to control truck hunting through application of reaction forces resisting such rotary movement which are effective primarily to resist higher velocity relative rotational movements.

Abstract: A damping device adapted for use in exercise apparatus includes a cylinder with internally threaded front and and rear end portions, a front cylinder cover and a rear cylinder cover, each of which has a threaded raised portion for engaging the internal threads of the cylinder and a central through hole as well as a valve hole in an upper side thereof; two valves respectively disposed in the valve holes of the cylinder covers; two C-clips for positioning the valve bodies inside the valve holes; a piston located inside the cylinder; a tube fixedly secured to the upper sides of the cylinder covers; a regulating rod disposed inside the tube and provided with valves for cooperating with vents in the bottom side of the tube, spring being fitted to a rear end thereof; and a stop element for controlling the displacement of the regulating rod inside the tube. The damping device does not require damping oil and permits regulation of the desired damping force.

Abstract: A vibration damping device comprises two cylindrical and flexible membrane members, a restricted passage constituting member connected at both end portions to these membrane members, two face plates connected at their end portion to the membrane members, a closed chamber defined by these members and face plates, a rigid member connecting both the face plates to each other at inside or outside of the closed chamber, a fluid filled in the closed chamber, and a fastening member disposed at each side of the restricted passage constituting member and the face plate.

Abstract: A conveying or transportation system having a haul rope (22) mounted for movement along a path, a terminal (31) positioned along the path and having a docking surface (52), and a carrier unit (27) coupled to the haul rope (22). The carrier unit (27) is coupled to the haul rope (22) by a rope coupling assembly (51), preferably in the form of a hydraulic piston-cylinder assembly (53) and fluid circuit (54), formed to create and maintain tension in the haul rope (22) during transport of the carrier unit (27) and formed for yieldable displacement of the haul rope (22) relative to the carrier unit (27) upon engagement of the carrier unit (27) with the docking surface (52) at the terminal (31).

Abstract: A hydraulic cylinder type high damping device in which a cylinder member or a piston rod member is connected to the frame of a structure and the other member is connected to an earthquake-resisting element integrally secured to the frame. A plurality of passages through the piston connect hydraulic chambers on opposite sides of the piston. The passages are provided with pressure-governing valves which control the flow of oil between the hydraulic chambers. In addition, an accumulator system provides a bypass for oil to flow between the hydraulic cylinders in order to modulate the oil pressure in the damping device. Relief valves are provided in parallel with the pressure governing valves to provide a variable damping coefficient which protects the damping device from overloads caused by excessive seismic shock.

Abstract: A shock absorbing apparatus comprises a cylinder body having a cylinder chamber formed therein, a piston body reciprocatively held in the cylinder chamber and having a pair of piston rods outwardly projecting through hole portions respectively formed at the two end portions of the cylinder chamber, and a shock absorber for absorbing motion when one of the piston rods projects over one of the hole portions and the leading portion of the other piston rod is stopped in the other hole portion, so that a shock generated at the time of collision with an object is absorbed.

Abstract: A damping apparatus including a piston having an axis therethrough. The piston includes a coaxial body portion and a first and second end extending oppositely therefrom along the axis. A rigid housing is coaxial with and surrounds the body of the piston for forming a rigid fluid volume between the piston and the rigid housing. The rigid fluid volume includes a first fluid chamber at a first end of the piston and a second fluid chamber at the second end of the piston. The first and second fluid chambers are connected by a damping path. The damping apparatus further includes a flexible housing coupled to the first and second ends of the piston and surrounding the rigid housing to form a fluid return of lower resistance to flow than the damping path between the rigid housing and the flexible housing and to allow movement of the rigid housing with respect to the piston.

Abstract: A hydraulic damper has a dashpot piston reciprocating in a cylinder bore. Piston rods extend axially from both sides of the piston. Sealing structures at both ends of the cylinder connect to the cylinder and sealingly engage the piston rods to form two symmetrical hydraulic working chambers divided by the dashpot piston. A narrow passage through the piston provides a restricted fluid flow path between the two working chambers for hydraulic damping of piston motion. A cavity in the first piston rod is provided with a spring-biased, sliding reservoir piston forming a pressurized hydraulic fluid reservoir connected to the midpoint of the narrow passage between working chambers by a narrow conduit. Both narrow passage and conduit have fixed dimensions and no valves. A cavity in the second piston rod contains a spring centering mechanism.

Abstract: The hydraulic damper according to the invention has at least one restricted communication passage (47) between its two working chambers (8, 9) whose cross section is controlled by a viscous restriction valve (51) positioned via a control pressure of a fluid of a control damper with at least one secondary chamber (41, 42) delimited in a secondary cylinder (39) by a control piston (40), which cylinder and control piston are integrally attached, one to the main body (1), the other to the damping piston (4) of the damper, such that the damping law of the control fluid positioning said valve (51) is linked to the relative displacements of the main body (1) and damping piston (4).Application to the equipping of elastic-return struts with integral damping, in particular for helicopter rotors and blades. FIG. 2.

Abstract: The hydraulic damper has at least one restricted communication passage (47) between its two working chambers (8, 9) whose cross section is controlled by a viscous restriction valve (51) positioned via a control pressure of a fluid of a control damper with at least one secondary chamber (41, 42) delimited in a secondary cylinder (39) by a control piston (40), which cylinder and control piston are integrally attached, one to the main body (1), the other to the damping piston (4) of the damper, such that the pressure law of the control fluid positioning said valve (51) is linked to the relative displacements of the main body (1) and damping piston (4).

Abstract: A hydraulically-operated piston device installed between the frame of a structure and a vibration-resisting element provided separately from the frame varies the rigidity of the frame by changing the condition of connection between the frame and the vibration-resisting element. A valve controls the operation of the piston device and can be adjusted to change the coefficient of damping of the piston device. To obtain maximum rigidity of the frame, the piston is hydraulically locked in place. For maximum flexiblity of the frame, the piston can be hydraulically released from a locked position to move freely. Hydraulic resistance to movement of the piston can be graduated by metering the flow of oil into and out of the piston device. The coefficient of damping is a function of the metered flow of hydraulic fluid in the piston device.

Abstract: A viscous damper wherein the viscosity of a fluid, such as an oil, is used to generate damping effect when the fluid is passed through a restricted orifice or slit. Electrodes are arranged to face each other across the orifice or slit so that an electric field is created in a direction which is transverse to the direction of the fluid flow in the orifice or slit. The voltage applied to the electrodes is controlled in accordance with a frequency of vibration of a vibrating member to be damped. The viscosity of the fluid is controlled by applying a voltage thereto, so that a desired damping effect is obtained within a wide range of the frequency of the vibrating body.

Abstract: A hydraulic vibration buffer for connection between two members with a case coupled with the first member, a piston rod with its top end coupled with a second member, a piston coupled with a base end of the piston rod and housed within the cylinder case so as to divide the cylinder case into first and second chambers, fluid source, a tank, and a control valve disposed in fluid paths connecting the cylinder case, the fluid source, and the tank with one another. The vibration buffer also includes returning-force application device constituted by a swingable link with its one and other ends coupled with the first member and the housing block through which the fluid paths extend, and a pair of springs disposed between a center portion of the swingable link and the spool of the control valve.

Abstract: A shock absorber including a main housing body having a cylindrical portion and closure portions closing the open ends of the cylindrical portion, an inner cylindrical member disposed within the main body and cooperating therewith to define an inner cylinder chamber and an outer annular space, and a piston slidably received within the cylinder chamber, so as to divide the cylinder chamber into two fluid chambers filled with an electro-viscous fluid. The fluid chambers communicate with each other through communication passage which includes a portion formed within the annular space. An operating and a balancing rod are secured to the piston and extend slidably through the respective two closure portions of the main body. The shock absorber includes at least one pair of electrodes one of which consists of a portion of the cylindrical portion of the main body and the other of which consists of a portion of the inner cylindrical portion.

Abstract: A double-rod hydraulic cylinder for an exerciser including a casing, a piston assembly and a universal joint. The piston assembly includes a piston head and two piston rods. Two bearings are respectively fixed to an inner wall of each closed end of the casing. A disk-type spring washer, a washer, an oil seal and a disk-like fixing gasket are arranged respectively in series from each bearing to said piston head. Each of the bearings, the disk-like fixing gaskets, the disk-type spring washers, the washers and the oil seals have a central hole in alignment for the piston rods to pass through. The washers, the oil seals and the gaskets are axially slidable a short distance within the casing. The two disk-like fixing gaskets and the piston head together define a first chamber and a second chamber. Each disk-type spring washer is compressed when the piston assembly axially moves in either direction. The hydraulic cylinder further includes an oil pipe.

Abstract: An isolating mount for connecting two parts or mechanisms includes a rigid bushing surrounded by a resilient block which includes cavities on opposite sides of the bushing located along a first plane parallel to the longitudinal axis of the bushing and passage formed between the cavities. A quantity of liquid fills the cavities and a passage, providing a liquid column of predetermined inertia in the passage between the cavities for controlling forces transmitted through the bushing to provide tuning of the damping characteristics of the mount to preselected frequencies of vibration. A rigid outer body surrounds and contacts the block and exerts compressive force thereon substantially along the first plane. The bushing is connected to one of the two parts to be isolated and the outer body is connected to the other of the two parts.

Abstract: The invention is directed to an improved exercise apparatus, of the type having a fixed base and an associated movable portion. A hydraulic system is attached to both by a cylinder, on movement of the movable portion with respect to the base, a hydraulic fluid current is generated through a flow control valve. By adjusting the flow control valve resistance to the current can be varied causing greater or lesser resistance to the exertions of the user of the apparatus. Preferably paired flow control valves are utilized providing adjustable accommodating resistance to movement in either direction. The adjustment controls are conveniently mounted on the movable portion for user/operator access.

Abstract: The technical field of the present invention is that of sealing devices between a piston rod and a cylinder of an artillery recoil brake. The piston divides the chamber into a high-pressure chamber and a low-pressure chamber. The volumes of the chambers vary according to the position of the piston relative to the cylinder. The sealing device according to the invention includes a "medium-pressure" chamber through which the piston rod passes, and which communicates with the high pressure chamber by means of a roughly annular channel surrounding the piston rod. The medium-pressure chamber is connected to the low pressure chamber by a pipe having a cross sectional area greater than that of the annular channel. The device is intended for applications to artillery material.

Abstract: Operation of a continuously variable semiactive damper of the system is modified so as to reduce generation in the system of undesirable shocks and noise. The modifications include delaying some or all of the changes in the on/off states of the damper, and/or limiting the rate and/or extent of changes in the damping coefficient of the damper at certain of the times when the damper is in an on state.

Abstract: A shock absorber having a casing containing compressible fluid and a piston head with structure for providing fluid amplification during normal piston head movement, the piston head having a central bore therein for slidably mounting the piston head for axial movement on the piston rod and being biased against a holding member by Bellville washers, a valve on the holding member obstructing conduits between the piston rod and the piston head when the piston head is biased against the holding member, the conduits being uncovered by the valve to permit flow therethrough from one side of the piston head to the other when the pressure in the shock absorber in the area of the holding member exceeds a predetermined value, the conduits between the piston head and piston rod being of a shape to provide a second stage of fluid amplified flow.

Abstract: The invention relates to a method of damping the pressure peak occurring at the end of the die filling phase in die casting machines, with a hydraulic damping device being disposed between the piston rod of the drive piston and the piston rod of the casting piston. The damping chamber of the damping device is closed by a control piston through which no fluid flows in the case of damping and which is not required to move against the direction of movement of the casting piston rod in order to open the control edge. It is here the object of the invention to shorten to a minimum the response time of the control piston. According to the invention, a device is proposed for this purpose which is characterized in that the chamber (25) disposed on the side opposite the reservoir chamber (10) of the control piston (4) is connected to a pressure medium conduit (26) in which a control valve (27) is disposed.

Abstract: The invention relates to an arrangement for damping shifting movements in a mechanical, synchronized multispeed transmission. Where such shifting movements are performed with the aid of a servo-mechanism, for exmaple a pneumatic piston cylinder unit, there is the risk that the gear teeth will be damaged when brought into engagement with each other. In the arrangement according to the invention, a pressure medium-filled damper is used without any communication with a separate pressure medium reservoir, thus eliminating the risk of malfunction due to foam formation in the pressure medium as well as achieving a desirable damping of the shifting movement. The invention is characterized for this purpose in that the piston in the damper is arranged on a piston rod which extends through the cylinder portion of the damper, so that upon relative movement between the piston and the cylinder portion, the volume of the damper filled with pressure medium remains constant.

Abstract: In an apparatus for damping courses of movement of two bodies or masses moving at variable velocities relative to one another and in their absolute positions, in particular for damping resilient wheel suspension systems in vehicles, in which a piston dividing a cylinder into two work chambers is dampingly affected in its particular movement direction (tension stage, compression stage) by controlled hydraulic throttle valves connected in series or in parallel with one another, parallel to the throttle valves, respective check valves opening in the opposite direction are provided, wherein the connections of all the valves remote from the work chamber connections are joined together and that a separate passive and (semi-) active damping effect be initiated. The necessary bandwidth of the frequency response of the electrohydraulic valves of apparatuses of this kind can be reduced drastically as a result.

Abstract: A hydraulic device for controlling the knee-joint function in a leg prosthesis has a cylinder which is divided into first and a second cylinder parts adapted to be fixed to the lower leg of the prosthesis, and a piston rod which carries one piston in each cylinder part and is fixed to the upper leg of the prosthesis. The pistons divide the interior of the respective cylinder parts into two chambers. The adjacent first chambers of the cylinder parts are interconnected by a throttle device. The two, second chambers are also interconnected. One piston has a sealing member which is of a single-acting type to allow leakage of hydraulic fluid from the second chamber to the first chamber when the piston is moved in a direction reducing the volume of the second chamber, while it is completely sealing when the piston is moved in the opposite direction. A connection is provided between one of the first chambers and one of the second chambers.

Abstract: A frictionless hydraulic damper including a cylinder having end walls mounting the opposite ends of a shaft in bushings with a clearance, bellows seals between each end wall and the portions of the shaft extending beyond each end wall, a piston head on the shaft within the cylinder, hydraulic fluid in the cylinder and in both bellows seals, an orifice construction located relative to the piston head for permitting flow of hydraulic fluid past the piston head to produce damping, and a conduit in the shaft for effecting communication between the two bellows. The damper as described above also functions as a snubber by including a valve construction which selectively closes the orifice construction. The damper as described above also includes structure which effectively closes off the clearances at the relevant bushings when the piston head travels above a predetermined velocity, to thereby prevent leakage past the bushings and thus enhance the snubbing action.

Abstract: A viscoelastic damper which is adapted to control the vibration of a structural member, a tank, a pipe, etc. which may be caused by an earthquake or wind while producing minimum reaction force when the structural member and so on is slowly displaced as a result of the thermal deformation of the member itself or another member connected thereto. Such a property of a viscoelastic damper can be obtained by using dilatant liquid which presents relatively small resistance when the speed of the motion is small and produces progressively great resistance as the speed of the motion increases. To the end of enhancing this favorable property of the viscoelastic damper, the shoulder surfaces that are exposed to the dilatant liquid are rounded. By providing a spiral groove or projection in the member exposed to the dilatant liquid to produce rotational motion between the two ends of the damper, this property is enhanced even more.