Abstract: Suspension strut comprising a cylinder and a spring perch which is axially displaceable relative to the cylinder for adjustment of the position, wherein the spring perch has a sleeve portion by which the connection to the cylinder is carried out. A chamber is arranged on the cylinder side which is at least partly filled with a moldable material. The sleeve portion contacts the moldable material, which in a solid state transmits a supporting force from the cylinder to the spring perch.

Abstract: A lower spring sheet has receiving portions on a sheet surface that supports a coil spring. Thus the sheet surface and a spring end portion of the coil spring come into contact discretely. The contact positions between the coil spring and the sheet surface maintain unchanged, however a undulated portion the spring end portion may have due to the manufacturing tolerance is extended when the coil spring is compressed.

Abstract: A dust cover receiving structure of a hydraulic shock absorber in which a sheet rubber is interposed between a suspension spring and a spring sheet. The sheet rubber has a spring receiving portion which is arranged and clamped between the suspension spring and the spring sheet, a centering portion which is fitted to a damper tube and guides an end portion of a dust cover in such a manner as to align the dust cover with an axial center of the damper tube, and a cover receiving portion which is provided between the spring receiving portion and the centering portion, and which receives an end surface of the dust cover.

Abstract: A spring element has a substantially cylindrical housing (125) and at least one spring (128) arranged therein. At least one guidance member (129) that radially braces the spring (128) is arranged between an outer side of the spring (128) and an inner wall of the housing (125).

Abstract: A vibration isolation spring mount is disclosed. A compression coil spring is inserted between an inner sleeve and an outer sleeve and a pair of pads are disposed on the inner sleeve and the outer sleeve. Outwardly extending blades disposed on the open end of the inner sleeve are inserted into the spaces defined by inwardly extending teeth disposed on the open end of the outer sleeve, then the blades are rotated relative to the teeth until the teeth and the blades impingingly engage due to the compressed compression coil spring biasing the teeth against the blades.

Abstract: The present invention is directed to a helical compression spring for a vehicle suspension to be compressed between an upper seat and a lower seat. The spring is formed to provide an end coil center line connecting the centers of an upper end coil and a lower end coil to be offset to a coil axis of a body portion of the spring. A pitch of the lower end coil is set to tilt a lower end plane of the spring at a first predetermined angle to the lower seat in a direction for shortening the longitudinal length of one side of the spring closer to the end coil center line than the coil axis, in an unloaded state of the spring, and/or a pitch of the upper end coil is set to tilt an upper end plane of the spring at a second predetermined angle in a direction for shortening the longitudinal length of the other side of the spring closer to the coil axis than the end coil center line, in the unloaded state of the spring.

Abstract: A lower spring sheet has receiving portions on a sheet surface that supports a coil spring. Thus the sheet surface and a spring end portion of the coil spring come into contact discretely. The contact positions between the coil spring and the sheet surface maintain unchanged, however a undulated portion the spring end portion may have due to the manufacturing tolerance is extended when the coil spring is compressed.

Abstract: A coil spring (1) and support bearing (2) arrangement for suspension struts (3) with a shock absorber, supporting a steering knuckle of an automobile has a rolling-contact bearing (7), with an axis (x); a receiving body (6), arranged below the rolling-contact bearing (7) in which the rolling-contact bearing is inserted; and a coil spring (1). The coil spring (1) has a force application line (f), which is offset relative to the axis (x) of the rolling-contact bearing (7) at an angle (a). The coil spring (1) has a first portion (8), which, starting from the winding end (17), winds around the receiving body (6). The first portion (8) abuts the receiving body (6). The winding end (17) of the coil spring (1) is arranged in the area of the plane E1 formed by the force application line (f) and the axis (x).

Abstract: The restoring coil spring of a vehicle shock absorber can be seated on an annular elastomeric pad that is equipped with a reinforced peripheral flange adapted to maintain the lowermost convolution of the spring on the elastomeric pad should the spring break during service. An annular steel band is incorporated into the elastomeric flange to provide a reinforced flange structure resistant to radial deformation.

Abstract: The invention relates to spring strut with a flexible pad between a coil spring and a spring-plate which is firmly connected to a cylindrical container of an oscillation damper. The flexible pad, which is used, in particular, for noise damping, is formed by a component of disk-shaped design which is flat on both sides, is composed of rubber, PU or some other plastic, and is connected in a captive and positionally correct manner to the spring-plate. For this purpose, at least one inward-pointing projection and/or at least one aperture is arranged on the flexible pad, interacting with a corresponding aperture and/or projection of the spring-plate. The flexible pad is adapted to the surface of the spring receptacle of the spring-plate by the prestressed coil spring.

Abstract: A non-linear non-circular coiled spring comprises a first coil portion of rectangular cross-section having a lateral length “a” and a longitudinal length “b”, a second coil portion of rectangular in cross-section having a lateral length “b” and a longitudinal length “a”, and a transition coil portion connecting the first coil portion and the second coil portion by gradually twisting one of first and second coil portions toward the other of first and second portions. The non-linear non-circular coiled spring is adapted to be used as a car suspension or a machine spring.

Abstract: The coil spring of a vehicle shock absorber can be seated on an elastomeric sound isolator pad whose spring engagement surface has plural slot-like depressions evenly spaced around the pad circumference. These slot-like depressions form raised ribs that provide the contact surfaces for the lowermost convolution of the coil spring. Each rib can readily deform under the spring force. Side surfaces of the ribs can act as heat-dissipating surfaces. The slot construction allows the pad to be formed out of a reasonably high durometer and highly wear-resistant elastomer without adversely affecting the desired rib deflection.

Abstract: A flexible connector which is a combination of a coil spring and an elastomeric sleeve is disclosed. This combination allows for greater strength and resistance to exceeding the strain limit of the coil spring.

Abstract: A vibration-damping rubber for a suspension of a vehicle is composed of a resilient rubber body adapted to be interposed between a plurality of members of the suspension. The resilient rubber body has a slide surface adapted to contact one of the plurality of members. One part of the resilient rubber body, which includes at least the slide surface, is composed of a rubber having high sliding characteristics.

Abstract: To avoid an increase of the number of steps for assembling a coil spring and seat members and a reduction in mechanical strength of the coil spring or the like, a coil spring assembly 20 is provided with the coil spring 25 and the seat members 26. Each seat member 26 has receivers 27 for contacting both ends of the coil spring 25 and projections 28 extending into the coil spring 25 from the receivers 27. Ribs 29 are formed on an outer circumferential surface of the projections 28 for engagement with the coil spring 25.

Abstract: A suspension system includes a shock absorber, a coil spring, a tubular dust cover, and an insulator. The shock absorber is provided with a first seat and a second seat at the opposite ends. The insulator is disposed between the first seat and the coil spring, and includes a body for holding the coil spring, and a contact projecting from the body in a centripetal direction and having a portion being brought into contact with one of the opposite ends of the dust cover. The insulator forms a space between the first seat and an outer portion with respect to the portion of the contact. Thus, the insulator reduces the wear of the first seat resulting from the contact with the dust cover, inhibits the first seat from corroding, and keeps the strength of the first seat from decreasing.

Abstract: A shock mitigating tether system includes a helical coil spring mounted within a tubular housing between opposing retention plates. A first cable is folded in half and journaled through the longitudinal axis of the spring such that a loop end projects from a first end of the spring and a pair of opposing ends of the cable are mounted to the tension plate on the second end of the spring. A second cable is also journaled longitudinally through the spring with a second cable loop projecting outwardly through an opening in the second plate and the second cable free ends mounted to the first plate, such that the cable loops project in opposing directions along the longitudinal axis of the coil spring. A pair of pins are mounted through diametric apertures in the ends of the housing outwardly of the plates, to retain the spring and plates within the housing.

Abstract: A bearing assembly is disclosed for supporting a coil spring, for example for an automobile suspension system. The bearing assembly includes an elastic support having a sloped spring supporting surface corresponding to the pitch of the spring. At the side opposite the spring, the elastic support is supported by a distance element. The distance element and elastic support are geometrically configured so that a uniform axial length of the elastic support member is disposed between the spring and the distance element over a substantial circumference of the coil spring. In certain embodiments, recesses are formed in the elastic support member for engaging with cams at the distance element, with the ends of the cams and the bottoms of the recesses dimensioned so that there is a constant height of the elastic support between the spring and the distance element.

Abstract: A first end surface of a coiled compression spring at its relaxed length is machined to a plane transverse to the spring axis. The spring is then placed in a press structure having first and second opposed planar support surfaces, with the machined spring end surface bearing against the first support surface, the unmachined spring end surface bearing against a planar first surface of a lateral force compensation member, and an opposite, generally spherically curved surface of the compensation member bearing against the second press structure support surface. The spring is then compressed generally to its loaded length, and a circumferentially spaced series of marks, lying in a plane parallel to the second press structure support surface, are formed on the spring coil on which the second spring end surface lies. The spring is then removed from the press structure, and the second spring end surface is machined to the mark plane.

Abstract: A variable force die spring is disclosed which combines high force, short axial compression distance spring assembly, such as belleville springs, and low force, high axial compression distance springs, such as coil springs, in a telescoping casing having an internal cavity. The springs are arranged within the cavity so that upon receiving a load the low force spring will compress first resulting in a large axial compression and low force resistance. The load applied to the telescoping casing will then transition from the low force spring to the high force spring. The high force spring then compresses as the load continues to be applied. In alternative embodiments, a third intermediate spring is added that compresses moderate distances under moderate pressure thereby increasing the overall axial compression and load capacity capabilities of the spring assembly.

Abstract: In disc brakes, disturbing noises, such as whistling or squealing, occurring during braking operations can be prevented if the brake shoe, to be pressed against a brake disc by a pressure member, for example a hydraulically actuated piston, is taken along in the circumferential direction of the latter as soon as the brake shoe comes into contact with the brake disc, and is laid against bearing faces of a brake anchor plate. Accordingly, the pressure member is provided, on its end face facing the brake shoe, a pressing element which projects beyond the end face, is transversely movable to a limited extent and returns automatically to its initial position again, and which is arranged in the pressure member so as to be axially displaceable counter to a return force which, in the event of mutual contact between the pressing element and brake shoe, is lower than the pressing force of the pressure member.

Abstract: A sugar cane piler having a mechanical spring suspension device connected between the piler and the front end of the loader, the device including a precompressed spring to absorb a major portion of the weight of the piler and reduce the force of the piler acting on the ground. The device permits the piler to readily float over the ground and minimizes penetration of the piler's tips into the ground.

Abstract: A support for a coil spring of a spring strut of a motor vehicle, which is cardanically disposed on the vehicle body, comprises a coil spring which, on one side, on the side of the vehicle body, is supported on an upper first elastic spring pocket and, on the other side, is supported by way of another lower second spring pocket which is stationarily held on the spring strut. In the operating direction of the coil spring, the upper spring pocket has areas of different elastic characteristics. In an area of high axial pressure forces of the compressed coil spring, the elastic characteristic of the spring pocket is less than in an opposite area of the spring pocket of lower axial pressure forces of the compressed coil spring. By means of this development of the spring pocket, a disadvantageous bulging of the coil spring during compression and rebounding movements is largely prevented.

Abstract: A spring system for applying an elastic restoring force to a moveable member undergoing a reciprocating movement. This spring system includes a coil spring made of steel and having a moveable end engaged to a moveable member and a fixed end engaged to a fixed member. The moveable end is formed as an open end. A spring seat member is interposed between the moveable end of the coil spring and the moveable member. The spring seat member has a receiving surface contoured to snugly receive the moveable end of the coil spring.

Abstract: A spring connector accumulator includes a helical compression spring, and a pair of connector body members that extend in opposite directions through the spring for maintaining the same in a predetermined preloaded partially compressed condition. The body members include first end portions adapted for connection with cable end fittings, respectively, intermediate portions that extend through the spring, and second end portions that abut opposite ends of the spring. In a first embodiment, the body members include main abutment surfaces that are snapped into abutting engagement to maintain the spring in a preloaded partially compressed condition. In a second embodiment, the spring is partially compressed to the desired preloaded condition between a pair of opposed spaced hook portions on each of the body members, respectively.

Abstract: A coil spring device comprises a coil spring formed of a spiral wire having a first end and a second end, a first end support mechanism supporting the first end of the wire, and a second end support mechanism supporting the second end of the wire. The paired support mechanisms are movable relatively to each other in the axial direction of the coil spring. The first support mechanism supports the first end of the wire for rotation only around a first diametrical axis which extends toward a coil central axis. The second support mechanism supports the second end of the wire for rotation only around a second diametrical axis which extends toward the central axis.

Abstract: A bicycle shock-absorbing apparatus comprises an inner tube and an outer tube. The inner tube is inserted into the outer tube. An upper spring socket and a lower spring socket are disposed in the inner tube and the outer tube separately. A compression spring is disposed between the spring sockets, oil being filled between the spring sockets. The inner tube is fixedly attached to the upper spring socket and corelatedly actuated with the spring to achieve a shock absorbing effect. A hole is formed in the center of the upper spring socket, enabling oil to flow therethrough. An oil seal is disposed inside the top of the outer tube to prevent oil spillage. An air inlet socket is attached inside an upper wall of the inner tube, while an air inlet valve is received by the air inlet socket to enable inflation of the inner tube. The air, in cooperation with the spring and the oil, provide elasticity for the bicycle shock-absorbing apparatus.

Abstract: A hydraulic pressure control device of a load sensing type is provided. The hydraulic pressure control device includes a spring support disposed on a vehicle body side or wheel side for supporting a suspension spring, a support member tiltably disposed in the spring support for supporting a load of the suspension spring at three support portions, and a hydraulic pressure control valve mounted on the support member for controlling hydraulic pressure supplied to a braking unit mounted on a wheel from a source for generating hydraulic braking pressure. Thus, at least a portion of the force applied to one of the support portions can be applied to a control piston of the hydraulic pressure control valve.

Abstract: A spring system for applying a restoring force to a reciprocating member such as an exhaust or intake valve of an internal combustion engine, comprising: a helical spring having open ends and consisting of titanium or an alloy thereof; and a spring seat supporting one of the two ends of the helical spring. Since this helical spring is provided with open ends, mutual striking of the coil wire can be avoided and, thereby, the durability of the helical spring can be ensured in addition to the advantage obtained from the low-mass and high transverse elastic modulus of titanium or its alloy.

Abstract: An interchangeable end mount system for stabilizer shock absorbers. Two types of end mounts are described, an eye ring end mount and a stud end mount. In one preferred embodiment, the eye ring end mount includes an eye ring, a threaded sleeve with a shoulder, and a washer. The end mount is removably screwed onto a threaded piston rod. An improved spring seat provides a bottom support for the shock absorber spring. A stud end mount embodiment includes an internally and externally threaded stud with a shoulder, and a washer. Another embodiment of the stud end mount does not have a shoulder or washer but uses cup washers and urethane doughnuts to retain the shock absorber spring.

Abstract: The rotary actuator includes at least a precompressed spring assembly comprising a compression coil spring the ends of which are engaged by flanged cups adapted to limit the spring extension and carried slidably on a pin provided, at each end, with a circlip which prevents the cups from coming off the pin itself.

Abstract: A two-stage automobile bumper comprising two buffers set in two inner supporting frames which are supported in two outer supporting frames welded at the front of the chassis and a bumper fixed at the front end of the buffers. When the bumper receives a shock, pins combining the buffers with said inner supporting frames are to be cut into two pieces and coiled springs are to be compressed to absorb the shock force.

Abstract: In an accumulator including a piston which slides freely in a cylinder and a spring which presses the piston, a hole of the piston end where, at the bottom, a large diameter section is made, and small diameter section whose diameter is smaller than that of the large diameter section is located at another side of the large diameter section is located at another side of the large diameter section against the bottom of the hole is provided, and the spring assembly having the retaining member and the coil spring whose one end is fixed to the retaining member and another end is free is provided, and the snap ring is provided to hold the retaining member between the bottom of the hole and the snap ring which is installed in the large diameter section with radial expansion force, so that the spring assembly is installed in the hole of the piston.

Abstract: The device comprises two rods which are each intended to be connected to one of the structural elements, and at least one helical spring whose ends are connected to two discs, each associated with one of the rods, so as to oppose the movement apart of the rods through the discs. The latter are mounted for axial sliding relative to the associated discs and are formed in such a way that their movement both towards and away from each other causes tensioning of the spring from its undeformed rest condition. The device acts as a rigid connecting element when thestresses applied to it are less than a predetermined threshold. When the stress exceeds the threshold, however, it deforms resiliently to limit the amount of stress transmitted to the members between which it is connected.

Abstract: A spring apparatus has a spring body including a plurality of elastic longitudinal beam members and a coupling beam member for holding the elastic longitudinal beam members at a predetermined interval. The apparatus further has a pair of spring retaining members for supporting the both ends of the spring body, and a rotary member rotatable provided around the central axis of the spring body as a center at least one one spring retaining member. At least one of the elastic longitudinal beam member is provided at one end of the rotary member. This spring apparatus is a tightly wound coil and made of the elastic longitudinal beam members in fully compressed state. When extended, each elastic longitudinal beam member is sequentially spirally deformed at larger pitch from the end. The twisting deformation of the elastic longitudinal beam member is released by rotation of the rotary member.

Abstract: A fluid pressure control valve includes a housing having an inner hole and a plunger movably disposed in the inner hole, the housing having inlet and non-pressure chambers defined herein at one end of the plunger and an outlet chamber defined therein at the opposite end of the plunger, the housing also having a passage communicating the outlet chamber with the inlet chamber. A valve device is disposed in the passage and openable and closable in response to movement of the plunger. A preloading spring is disposed in the housing for normally urging the plunger in a direction to open the valve device. The housing comprises a cylindrical member having one open end and a cover member closing the open end. A spring seat is disposed in the cylindrical member in engagement with the cover member, the preloading spring acting between the spring seat and the plunger. The spring seat is force-fitted in the inner hole of the housing or in the cover member.

Abstract: A die spring retainer for vertically affixing a die spring to a die set is configured as a generally circular blank defining a central opening adapted to receive a pilot screw therein. The blank includes a major portion having a first diameter and a minor portion having a second diameter less than the first diameter. The minor portion constitutes approximately 30 degrees to 120 degrees of the external circumference of the blank. The blank is fabricated from a deformable material and deforms under compression to the configuration of the first coil of the spring, thus securely affixing the die spring to a die set.

Abstract: A spring system for resiliently supporting a mass with respect to a base comprises a supporting member mounted for movement and which can be coupled to the mass and is bounded by a portion of a spherical surface which bears against a concentric complementary guiding spherical surface fixed with respect to the base to guide the supporting member to rotate in all directions around the center of the sphere. A circular resilient device is provided in engagement with the supporting member and is supported with respect to the base. The supporting member is coupled to the mass at a point inside the circular resilient device whereby the supporting member is tilted by radial shocks while its spherical surface is guided along the guiding spherical surface and by the deformations of the resilient device as a result thereof, a resilient couple and/or a radial resilient force is developed which tends to move the supporting member into its initial position.

Abstract: A helically-threaded spring holder on which a helically wound spring is mounted has a groove formed in one side of the thread at the end where the spring engages the spring holder. The groove relieves the portion of the side in which it is formed from restricting the spring against axial movement during deflection of the spring. The circumferential length of this groove is chosen to establish the number of spring coils which can be deflected without contacting the side of the thread. The end of the thread is also made rigid to prevent flexing thereof during maximal elongation of the spring.

Abstract: A pair of identical rigid arms are each pivotably attached at one end to a pair of identical brackets, one bracket attached to a boat and the other bracket attached to a dock, and an elongated helically wound spring is threaded on to each end of the arms to connect them together. The arms are held in place at the bracket by pins or rods which, particularly at the boat bracket, can be quickly and easily removed to free the boat.

Abstract: An apparatus for loading a wheelchair or similar object into a vehicle. When in a stored position, the apparatus and wheelchair are fully contained within said vehicle. A first embodiment illustrates use of the apparatus in a rear compartment of a station wagon, van or similar vehicle in which a pair of motor-driven drive links and a pair of drag links are utilized to lift and rotate a chair rack and wheelchair mounted thereon into said vehicle rear compartment. The drive and drag links connect the rack to a carriage which may then be rolled from a rearwardmost to a forwardmost position for final storage of the apparatus and chair in the vehicle. Latching means is provided to latch the carriage in either its forwardmost or rearwardmost positions. A remote control switch and limit switches are used to control power to the electric motor. A second embodiment of the apparatus is designed for use in the trunk of a typical passenger automobile.

Abstract: A seat suspension for resiliently attaching a seat assembly to a support frame on a vehicle so as to cushion the ride for the seat occupant comprises: main biasing springs operatively connected between the seat assembly and support frame to initially absorb energy and limit descent as the seat assembly is forced downward; auxiliary biasing springs, including a "hard" spring and a "soft" spring, to subsequently absorb energy and further limit descent after the main springs have been compressed a predetermined amount; and a shock absorber connected between the seat assembly and support frame to dampen vertical motion. A preloading apparatus is provided for adjusting or preloading the main biasing springs to take into account the weight of the seat occupant. A height adjusting apparatus is provided to adjust the height of the seat assembly and associated biasing springs relative to the support frame.

Abstract: An electromagnetically-actuated fuel injector of the type having a spring-biased flat armature and a ball valve element is provided with an improved arrangement for preventing wobble or flutter of the armature, particularly during operation. The armature and ball valve are urged to the closed position by a helical coil spring coaxially aligned with and acting in compression against the armature. The end of the spring in engagement with the armature is modified or formed such that it includes a portion which is inclined axially from a plane normal to the axis of the armature so as to concentrate most of the axial spring force at the location where it engages the armature. As that location is to one side of the axis of the armature, the remote, or opposite, edge of the armature forms a pivot with a stationary part of the injector and reduces or eliminates armature wobble.

Abstract: An overtravel spring assembly including a helical-type spring secured in a cylindrical housing in a prestressed state between retaining washers inserted adjacent the opposite ends of the housing. The spring is coaxially disposed in the assembly between the inner surface of the housing and the outer surface of a sleeve member inserted within the spring, thereby retaining the spring in a symmetrically coiled state, that is, preventing radial distortion or buckling of the spring spring when subjected to operating stress. The entire spring assembly is retained in its assembled state by radially crimping the opposite ends of the housing against the outer radial surfaces of the retaining washers. The overtravel spring assembly is used in an automatic slack adjuster for vehicle brakes for measuring the extent of overtravel of the piston rod due to excessive wear of the brake shoes.

Abstract: In a shock strut for a vehicle including a spring plate for supporting a helical spring, a receiving or catching member is connected to the spring plate. The receiving member prevents any lateral movement of the helical spring in the event of a spring failure. A simple connection of the receiving member to the spring plate is provided independently of the materials used for these members. The connection is afforded by downwardly projecting parts on the receiving member which extend through suitably dimensioned openings in the spring plate.

Abstract: An adjustable boat motor support means attachable to the boat transom or trailer and motor to prevent damage to the boat transom during transporting which is caused by the motor kicking up or shaking during hauling on a trailer is provided, comprising a vertically expandable first assembly pivotally mounted at one end to the boat transom and having a seating member at its opposite end in which the lower motor housing can rest, and a motor attachment assembly vertically, adjustably attachable at one end to the first assembly and attachable at its opposite end to the lower motor housing.

Abstract: An apparatus for adjusting the spring characteristic of a helical spring has a manually actuatable adjusting element, which comprises a rotational support for the windings of a spiral spring. The apparatus further has a retaining member and an arresting member for retaining and securing the adjusting element in the adjusted positions. To provide a separate adjustability of the spring pitch and the spring biasing, the retaining member and arresting member are embodied such that the adjusting tang is rotatable without its axial position being varied, and is fixable in any rotated position.

Abstract: A pressure operated regulator valve has a regulator spring that is held in place by a spring holder. The spring holder may be inserted into a spring housing and once inserted is locked in place. Adjustment of the valve spring may be made but the spring cannot be removed.

Abstract: A spring return for the reciprocable slide of an hydraulic distributor. The return spring is trapped between flanges of opposed cup-shaped rings. The cup-shaped rings have conical sections which are positioned inside of the spring, but which do not contact the spring. Each cup-shaped ring has a transverse bottom, and each of the transverse bottoms surrounds the slide and contacts only a cylindrical centering section on the slide. The cylindrical centering sections on the slide are short, and each cylindrial centering section loses contact with the surrounding transverse bottom of the cup-shaped ring shortly after the slide moves relative to such cup-shaped ring.

Abstract: A shock absorber assembly for an automotive vehicle suspension prevents transmission of vibrations such as road shocks. The shock absorber assembly has a resiliently shock absorbing spring seat retaining a suspension coil spring. The spring seat is adapted to absorb relatively low-amplitude, high-frequency vibrations and thus prevent the shock absorbing assembly from surging. The spring seat has resilient characteristics in which the minimum damping force occurs at a position normally maintained by the vehicle and in which the spring seat becomes rigid in response to relatively high-amplitude vibrations.