Abstract: A rack and pinion steering gear assembly including a housing, a rack that is translatably moveable relative to the housing along an axis and a bushing operably disposed between the rack and housing. The bushing defines a gap which extends the entire axial length of the bushing. At least one compressible member may be disposed between the bushing and the housing with the compressible member extending across the gap in the bushing and fully encircling the bushing. The bushing may also include a radial flange that acts as a travel stop. The bushing may also be formed of an acetal material wherein the flange and a tubular portion of the bushing are axially separated by an intermediate portion having a relatively thin radial thickness. Axially extending recesses may be provided to enhance the flexibility of the bushing.

Abstract: A support device for a bearing assembly includes a housing with a bore and a centerline and a bearing having a bore for receiving a rotatable shaft. The support device has an annular body disposable within the housing bore and having a central axis and inner and outer surfaces extending circumferentially about the axis, the inner surface defining a central bore for receiving the bearing. One or more first integral spring portions extend generally between the inner and outer surfaces and have a first stiffness and one or more second integral spring portions are each spaced circumferentially from the first spring(s). The second spring extends generally between the inner and outer surfaces and has a second, greater stiffness. The body is adjustably angularly positionable about the body axis to adjust a position of the shaft axis with respect to the housing centerline when disposed within the support bore.

Abstract: The present invention provides a rotating-body support structure that is capable of obtaining a damping effect of a rotating body with a simple configuration. To this end, the rotating-body support structure is configured to include a housing (21) and a bush portion (24) which is supported by the housing (21) and which rotatably supports a boring bar (11); and to have oil filled between the housing (21) and the bush portion (24).

Abstract: A tilting pad journal bearing, an annular housing for an array of arcuate bearing pads resiliently mounted by spring means which biases the pads against heads of restraining bosses that limit radial displacement and cause the bearing pads to define a shaft space. The pads have associated therewith support pegs secured to housing or pad at one end and movable relative to the pad or housing at the other, and the spring means comprises stacks of individually deflectable elements mounted between relatively moving pad, housing or peg and pre-loaded by adjusting the effective gap with the pads against the bosses. Relative movement between springs provide friction damping. The restraining bosses may be displaceable together to eliminate the shaft space clearance if the magnetic suspension fails or shows signs of failing.

Abstract: To provide a bearing support structure and a gas turbine that prevent damage of device induced by a rotor shaft when the rotor shaft is unbalanced, the bearing support structure and the gas turbine includes: a casing (7) formed in a cylindrical shape; a bearing unit (8) formed in a cylindrical shape and housed in the casing (7); a rotation shaft (5) rotatably supported by the bearing unit (8); and a reaction-force decreasing unit (13) that connects the casing and the bearing unit, and is configured to decrease a radial reaction force on the bearing unit side.

Abstract: A support for a bearing that guides a shaft in a turbomachine, comprising an annular part made of a shape memory material which retains an initial shape when the load applied to it remains below a threshold value and which deforms, absorbing energy when the applied load becomes at least equal to the threshold value, this annular part being capable of reverting at least approximately to its initial shape when the applied load drops back below the threshold value.

Abstract: A bushing assembly is disclosed and includes a bushing that can have an outer surface and an inner surface that can define an opening. The bushing can be configured to fit into a bore and receive a shaft through the opening. An engagement torque, T, between bushing and the shaft does not increase more than twenty-five percent as an interference fit between the bushing and the bore increases. The interference fit can be quantified by a reduction in outer radius, I, by at least 0.025 mm.

Abstract: A bearing device is composed of a shaft, a sleeve for supporting the shaft so as to be rotatable freely and a housing having a through hole into which the sleeve is inserted. A circumferential groove that extends in a circumferential direction is formed on either one surface of an outer circumferential surface of the sleeve and an inner circumferential surface of the housing. An axial groove that extends approximately in parallel to a central axis of the sleeve is formed on either one surface of the outer circumferential surface of the sleeve and the inner circumferential surface of the housing. The outer circumferential surface of the sleeve is glued to the inner circumferential surface of the housing by adhesive that intervenes in both the circumferential groove and the axial groove.

Abstract: A support member 10 for a rotatable element 42 comprising at least two pairs of ribs 30, 32 attached to opposing sides 22 of the support member 10, each pair of ribs 30, 32 adapted to receive guide walls 38 of a housing for the rotatable element 42 tightly therein; a supporting end 18 between the opposing sides 22 into which the rotatable element 42 can be received and supported along its axial length; and a retaining end 20 between the opposing sides 22, and opposite the supporting end 18, adapted to restrict axial movement of the rotatable element 42 when received within the supporting end 18.

Abstract: A bearing structure has a bearing and a shockproof structure. The bearing is disposed in a bushing. The shockproof structure is disposed in the bushing for covering at least one portion of the outer wall of the bearing.

Abstract: A coupling for resilient interconnection of two objects, especially a wheel axle housing and a chassis of a vehicle. The coupling comprises an elongated supporting piece (50), which extends in a longitudinal direction and two end attachment portions (52, 54) and a central portion (56). The coupling also comprises an elastic element (60), which is arranged around the central portion (56) and has an approximately cylindrical outer surface (64) and two end surfaces (68, 70). The coupling further comprises a first and a second abutment member (82, 84), where the first abutment member (82) has a bottom (90) and a tubular portion (86), which is fixed to the bottom (90) and has an open portion and a cylindrical inner surface (98). The bottom has a trough-going hole (106) through which one end attachment portion (52) can extend. The second abutment member (84) has a hole (108) through which the second end attachment portion (54) can extend.

Abstract: A sliding bearing for a steering column includes: a cylindrical bearing body; flat surfaces formed integrally on an inner peripheral surface of the bearing body; first slits extending from one end face of the bearing body to this side of the other end face of the bearing body; second slits extending from this side of the other end face of the bearing body to the one end face of the bearing body; grooves formed in an outer peripheral surface of the bearing body; and elastic rings which are respectively fitted in the grooves in such a manner as to project from the outer peripheral surface of the bearing body and to reduce the diameter of the bearing body.

Abstract: A roller device for attaching to a shaft of a treadmill, includes a tubular housing having two carriers engaged in the end portions, and the carriers each includes a casing directly folded from the end portion of the housing, and two bearing members are engaged in the casings of the carriers, for engaging with the shaft, and for smoothly and rotatably attaching the housing to the shaft, and for allowing the roller device to be easily and readily attached to treadmills. The casing includes an outer peripheral flap formed integral with the housing, and includes an outer diameter smaller than an inner diameter of the housing, for resiliently supporting the casing within the housing.

Abstract: A contour or profile of a bore of a locomotive traction-motor support bearing structure, where such profile preserves the currently center-loading of the upper load zone but moves inboardly the lower load zone to a more general central location. The profile of the bore for the support bearing, according to the invention, takes into account not only truck-axle bending due to locomotive weight, but also that from motor tilt through bearing clearances, and couple action on the axle from heavy radial loads on PE support bearing and adjacent axle gear. The bore is configured such that the upper surface is horizontal, but the lower surface slopes downwardly in the outboard direction at an angle based on a function dependent upon the three misalignment factors.

Abstract: A reciprocating piston mechanism for an air-conditioning compressor in a motor vehicle has a housing, a rotary driven shaft, a shaft seal assembly with a gliding ring seal, at least one radial shaft bearing, and at least one axial shaft bearing.

Abstract: A bearing for rotatably supporting a cylindrical shaft within a frame cylindrical support surface in which the shaft is subject to thermal expansion, the bearing being formed of a tubular member having opposed ends and having an axial passageway therethrough, the outer surface of the bearing member having an external circumferential rib adjacent each of the ends, each rib having an external diameter that permits the bearing member to be slideably positionable in the frame internal cylindrical support surface, the axial passageway being defined by a central bearing surface of internal diameter to rotatably receiving the shaft, the bearing surface having an axial length less than the spacing between said ribs, the bearing being deformable within elastic limits permitting the internal diameter of the bearing surface to expand to accept thermal expansion of the shaft.

Abstract: A pintle bushing assembly for a poppet valve assembly including a tolerance ring which is disposable between the pintle bushing and a bore in the body of the valve to both seal and center the bushing in the bore. The tolerance ring includes a plurality of radially-extending dimples which are deformable during assembly such that the valve pintle can be aligned coaxially with the valve seat under all conditions. An axial flange on the tolerance ring is sealed against axial surfaces of the valve body adjacent the bore and a flange on the bushing to prevent leakage past the bushing.

Abstract: A bearing system for a rotor shaft is provided in which a bearing prepared from a high performance polymer is surrounded by an elastomer sleeve that dampens the effect of noise and vibration caused by movement of the rotor shaft against the bearing.

Abstract: A sliding bearing for a steering column includes: a cylindrical bearing body; flat surfaces formed integrally on an inner peripheral surface of the bearing body; first slits extending from one end face of the bearing body to this side of the other end face of the bearing body; second slits extending from this side of the other end face of the bearing body to the one end face of the bearing body; grooves formed in an outer peripheral surface of the bearing body; and elastic rings which are respectively fitted in the grooves in such a manner as to project from the outer peripheral surface of the bearing body and to reduce the diameter of the bearing body.

Abstract: Existing bearing spring plates for a certain class of steam turbines fail due to a combination of static stresses and cyclic stresses over a long period of time leaving the bearings unsupported. The failures typically occur at welds between the flexible support plate and the pedestal base plate. A method to replace the broken spring plate to return the steam turbine to service is provided. A replacement bearing spring plate pedestal has a flexible plate integral with top and bottom mounting blocks. The flexible spring plate and mounting blocks meet at large radii, polished and substantially free from stress risers. A drill fixture permits drilling and tapping holes in the pedestal base plate to install the replacement spring plate pedestal at the proper location. The bottom block is secured as by bolting with epoxy to a pedestal base plate, and a top block is bolted onto a bearing-supported yoke.

Abstract: A compressor is driven by a drive shaft rotatably supported by a main bearing housing and a lower bearing housing. The main bearing housing positions a main bearing at or near a nodal point of the drive shaft during vibration by the drive shaft. The main bearing housing is designed such that the main bearing pivots during the vibration of the drive shaft in order to maintain surface contact between the bearing and the drive shaft to eliminate edge loading of the bearing.

Abstract: The concept of the invention is based on a machine housing with a bearing housing, the bearing seat of which is connected to a housing wall of the machine housing by a bearing housing wall provided with ribs (42, 43) and is subjected to radially directed forces (11, 44). The proposal is made that the bearing housing wall possess at least one ring shaped annular rib (42) which at least partially encompasses the bearing seat in an area (21), the angle (&agr;) of inclination of which, relative to its original unloaded condition, would change itself to the greatest extent under load (11). Further proposed is that a plurality of additional ribs (43) run transverse to the annular rib (42). Thereby, with a relatively small consumption of material, a good shape-retention is achieved. In addition, a tilting of the bearing seat and the bearing is held to a lesser extent than is the case of conventional bearing housing structures.

Abstract: A bearing structure includes a bearing having a shaft hole formed by an inner wall of the bearing. The outer periphery of the bearing has multiple outer walls and multiple deformable zones. The multiple outer walls are located at the axial direction of the same radius circumference with the center of the shaft hole as a center of circle thereof. Each of the multiple deformable zones is provided on the outer periphery of the bearing between any two outer walls, and is deformable to absorb an outer stress. When the bearing is closely mounted in a shaft tube during a punching process, the multiple deformable zones of the outer face of the bearing may absorb the outer stress, thereby preventing the inner wall of the bearing from being deformed.

Abstract: In a magnetic bearing apparatus provided at least with a touchdown bearing and a corrugated plate-like damper member inserted into an annular gap between the touchdown bearing and its retainer member, to keep on holding the corrugated plate-like damper member in a predetermined position without fail. A cylindrical retainer member 9 is a thrust bearing retainer member and also a touchdown bearing retainer member. A touchdown bearing 4, i.e., a pair of roller bearings 4a and 4b disposed in upper and lower stages are received in an inner circumferential portion of the cylindrical retainer member 9. An annular gap G is formed between the inner circumferential surface of the cylindrical retainer member 9 and outer races of the pair of roller bearings 4a and 4b. A pair of corrugated strip steel plates 8a and 8b that are the corrugated plate-like damper members are inserted into this annular gap G.

Abstract: The cab is supported at the front by elastic bearings mounted on bearing axles in alignment with each other and supported by at least two brackets attached to the vehicle frame. The elastic bearings are mounted in bearing shells attached to the floor of the cab. Each elastic bearing includes a rubber bearing with a plain bearing coaxial to it. An arresting device between the plain bearing and the elastic bearing presents relative rotation until a threshold torsional load is exceeded.

Abstract: The invention provides a weight-reducing bearing assembly for rotary aircraft. An opposed tapered conical elastomeric flap bearing assembly for rotary aircraft includes an outer housing having an outer surface and an inner surface. The outer surface is configured to mechanically connect the bearing assembly to the attachment sections of the hub center body. The inner surface is configured to receive a pair of opposed taper conical bearing elements. An inboard bearing element and an outboard bearing element are located within the outer housing. The bearing elements are arranged in an opposed manner. An axial pre-load can be applied to the opposed bearing assembly wherein the resulting force couple bearing pre-load path is maintained entirely within the bearing assembly. Consequently, the weight of the main rotor hub is reduced increasing the efficiency of rotary flight.

Abstract: An improved flexible support for a steady bearing in rotational contact with the surface of a shaft allows the bearing and housing to substantially track the contact surface of an impeller shaft when the shaft is subject to elastic deflection during operation. The flexible support employs a flexible disc pack, which is comprised of a plurality of thin, flexible disc elements in a stacked arrangement. The disc pack is mounted to a support ring and is also mounted to the bearing housing such that the bearing housing and other bearing elements are capable of deflection to substantially align with the axis of the impeller shaft when the shaft deflects.

Abstract: The expandable rack bushing has a tubular portion with front slots and rear slots. An axial overlap between the front and rear slots permits expansion and retraction of the tubular portion. Retainer blocks on the tubular portion are received in a radial groove in a rack and pinion housing to axially fix the rack bushing. When the steering rack is positioned in the rack bushing, the retainer blocks cannot be removed from the radial groove. Radial forces on the steering rack expand the rack bushing and move the steering rack toward one side of the rack housing bore. Spring fingers absorb energy as the rack bushing is expanded. These spring fingers continuously urge the steering rack toward the housing bore center.

Abstract: A cap of synthetic resin material for separating the wet and dry spaces of a motor/pump assembly and receiving the rotor of the motor has, at a bottom of the cap remote from the pump, a seat formed by axially-extending centering elements and detent arms which snap onto one of the bearings of the motor shaft and form-fittingly that retains that bearing in the axial and radial directions and prevents rotation thereof.

Abstract: An electric submergible pumping system having a submergible electric motor with a unique rotor bearing system to promote longevity of the motor. The system includes an electric motor having a housing and a stator mounted within the housing. A shaft is rotatably mounted within the housing for rotation within an interior, axial passage through the stator. A rotor bearing assembly is disposed intermediate the stator and the shaft. The assembly includes a bearing sleeve mounted adjacent the shaft, and a main body portion disposed in sliding engagement with the bearing sleeve. A spring mechanism, such as a wave spring, is engaged with the main body portion. A bracelet is located between the spring mechanism and an interior surface of the stator. The spring mechanism biases the bracelet against the stator to prevent the body portion from rotating during rotation of the shaft.

Abstract: A conveyor roller includes a generally cylindrical roller tube and a pair of stub shafts rotatably mounted in each end thereof. At least one of the stub shafts is mounted for axial movement between an extended position and a retracted position. When in the extended position, the stub shafts on each end of the conveyor engage respective mounting holes in the conveyor frame. To insert the conveyor roller in the conveyor frame, the movable stub shaft is moved to a retracted position while the roller is lowered into the conveyor frame. When the stub shaft aligns with the mounting holes in the conveyor frame, the stub shaft is urged back to the extended position by a biasing member to engage the mounting hole in the conveyor frame.

Abstract: The invention relates to a bearing device for a spindle, for example, for a dielectric tuner (13) in a cavity filter for electromagnetic waves. The bearing device comprises at least two sprung tongues (27), each of which has a stud (28) with a partially spherical free end, where at least two of the free ends are in contact with a sliding surface (21, 44). The invention also relates to a cavity filter and a method for assembling the cavity filter.

Abstract: A floating bearing system comprising a bearing supported in a clearance fit within a bearing bracket, for example for use in fractional horsepower shaded pole type electric motors. The bearing system is self aligning, to compensate for deviations in the axial alignment of the rotor shaft. A rotation lock restrains the bearing against rotation within the bearing receptacle while allowing the bearing to settle into proper alignment with the rotor shaft by automatically shifting the pitch of the axis of the bearing. In the preferred embodiment the bracket is composed of an engineering plastic and the bearing is composed of a high performance plastic polymer, so that the bearing system is non-lubricating. In the preferred embodiment the bearing bracket is provided with retaining fingers which hold the bearing in place during the assembly and working life of the motor.

Abstract: A shock-absorbing device is intended to be mounted on a spindle headstock of a machine tool. The spindle headstock includes a motor driven spindle unit connected to an upright by a support. The shock-absorbing device comprises a yieldable structure connected on one side to the spindle unit and on the other side to the support, and is adapted to yield upon an accidental collision of the spindle headstock against a workpiece. A collision sensor or is associated with the yieldable structure for detecting the yielding thereof resulting from an accidental collision of the spindle headstock with a workpiece, and for transmitting in response thereto a signal to a machine tool control unit.

Abstract: The cab is supported at the front by elastic bearings mounted on bearing axles in alignment with each other and supported by at least two brackets attached to the vehicle frame. The elastic bearings are mounted in bearing shells attached to the floor of the cab. Each elastic bearing includes a rubber bearing with a plain bearing coaxial to it. An arresting device between the plain bearing and the elastic bearing presents relative rotation until a threshold torsional load is exceeded.

Abstract: This system for fixing and guiding a bearing (3) in a slot (5) in a frame (8) comprises elongate flat fixing members (14) extending straddle-fashion between the coplanar respective end faces of the respective uprights (6, 7) of the frame and of the said bearing (3). Extending through each of said fixing members (14) are three cut-outs, one of which is in the form of an elongate closed opening and the other two in the form of slots open at one of their ends, disposed at the respective two ends of the said elongate opening. A strip perpendicular to the said uprights (6, 7) is formed between said elongate opening and each of said open slots adapted to form in the said fixing member (14) two fixing lugs disposed on either side of said slot, one lug being fixed to the upright (6; 7) and the other to the said bearing (3).

Abstract: With the invention liquid lubricated radial sliding bearings are shown, of which the bearing sleeve is elastically fastened in an outer part and forms an elastic journalling with a shaft part which can follow thermal heat expansions and inclined positions of the shaft to a limited extent. Because the bearing material is fastened in a bearing ring and the outer part is formed in a single part to a resilient ring and a support ring which has resilient support surfaces which are directed inwardly and at which the bearing ring lies under a bias force, elastic bearings for high and low temperatures and for differently corrosive lubrication liquids are possible with the same outer dimensions.

Abstract: A sliding bushing for providing rotational support of a rotating member and axial biasing of that rotating member. The sliding bushing includes a body portion and a biasing portion. The body portion defines an inner periphery and an outer periphery while the biasing portion extends from the body. The sliding bushing is an integral unit.

Abstract: A bearing has a composite elastic member, which supports a shaft. The composite elastic member comprises an elastic cylinder, which is made of an elastic material such as rubber and is provided at a bearing body section; and a spiral member, which projects from the circumferential surface of the elastic cylinder and is spirally assembled on the elastic cylinder. A lubricant is supplied to a spiral gap, which is divisionally formed between threads of the wire material forming the spiral member. When the shaft rotates, leakage of the lubricant is prevented by pumping operation and leakage of a fluid is prevented.

Abstract: In a nutating machine such as a high intensity comminution machine having a nutating drum (1), a support bearing is provided by pairs of rolling bearing surfaces (6 and 8, and 7 and 9). In order to reduce power requirements and wear, each pair of complementary contact paths traced out by the bearing surface pairs has an equal ratio of (a) the path length of the stationary bearing surface (8, 9) to (b) the path length of the nutating bearing surface (6, 7). In one embodiment, irrotational movement of the nutating element is achieved by having equal path lengths as between the stationary bearing surface and the nutating bearing surface in both pairs.

Abstract: The invention provides a submersible pumping system which includes a motor containing self-centering rotor bearing assemblies. Each rotor bearing assembly in accordance with the present invention includes a sleeve, a journal, and at least two seals. The journal is preferably disposed about the sleeve which is keyed to the power transmission shaft of the motor. The journal has a peripheral surface which is configured to have at least two circumferential support regions which are spaced apart from one another. Each of these circumferential support regions supports a corresponding seal. Each seal includes an interface member and an activating member. When in place in a rotor section of a submersible pump motor, the seals frictionally engage the inner surface of the stator and exert a centering force against the journal and thus against the bearing sleeve and the power transmission shaft.

Abstract: A conveyor roller includes a generally cylindrical roller tube and a pair of stub shafts rotatably mounted in each end thereof. At least one of the stub shafts is mounted for axial movement between an extended position and a retracted position. When in the extended position, the stub shafts on each end of the conveyor engage respective mounting holes in the conveyor frame. To insert the conveyor roller in the conveyor frame, the movable stub shaft is moved to a retracted position while the roller is lowered into the conveyor frame. When the stub shaft aligns with the mounting holes in the conveyor frame, the stub shaft is urged back to the extended position by a biasing member to engage the mounting hole in the conveyor frame.

Abstract: A bushing mountable in a housing for supporting a rotating member and for providing a bias force to the rotating member in a first direction is disclosed. The bushing includes a body defining an aperture therein and a mounting member for mounting the bushing to the housing. The bushing also includes a biasing member operably associated with said body and said mounting member. At least two of said biasing member, said mounting member and said body are integral with each other.

Abstract: The invention provides a motor and a bearing support and motor housing assembly, wherein the bearing support is detachably mounted to the housing with a flexible fastener, such as a snap ring. A resilient member, such as a spring washer, is seated between the fastener and either the housing or the bearing support to apply a biasing force against the fastener.

Abstract: A spherical bearing used in a rod end housing is modified with an elastomeric member equally precompressed in an amount of about 30% of an unstressed thickness of the elastomeric member to isolate the transmission of vibrations and sound. Such spherical elastomeric bearings can be used in any application where a conventional spherical bearing is used such as cable connections, clutch linkages, etc., in trucks, farm tractors, and various other pieces of equipment.

Abstract: A rotation center type joint has a one-piece body with an inner part, an outer part and a plurality of elastically deformable transverse arms inclined relative to the axis of the body, linking the inner and outer parts and converging towards the rotation center.

Abstract: An improved alternating current generator for a vehicle which is directed to forming a plurality of inserting holes of the rear bracket by concurrently forming the same during a die-casting process or by forming the same during a subsequent process, which includes a plurality of elastic plates spaced-apart from one another at a predetermined interval at the rear bracket so as to prevent a creep phenomenon by elastically supporting an outer circumferential portion of the rear bearing wherein a rear bearing creep prevention apparatus for an alternating current generator for a vehicle comprises a stator fixedly inserted at front and rear brackets; and a rotor supported by a shaft in cooperation with the front and rear bearings assembled at the front and rear brackets to be opposite to a core of the stator and being rotatable by a driving force transferred from an engine.

Abstract: A device for rotatably supporting a gear shift tube within a tubular steering column of an automotive vehicle. The device comprises a support of integral, one-piece construction made of an elastomeric, resinous plastic material disposed within a cup rigidly secured in the lower end of the steering column. The support comprises an open-ended bearing sleeve co-axial with the cup having an end portion extending through an opening in the bottom wall of the cup. The sleeve has angularly spaced abutments inside the cup abutting the inner surface of the bottom wall of the cup around the opening. The sleeve also has angularly spaced tangs outside the cup extending radially outwardly and abutting the outer surface of the bottom wall of the cup around the opening. The abutments and the tangs cooperate in locking the bearing sleeve axially within the cup. The bearing sleeve is preferably made of urethane reinforced with glass fibers.

Abstract: A spring cartridge rotor bearing is inserted into an electric motor during assembly as a preassembled unit. The rotor bearing includes a sleeve having a bore adapted to receive therethrough a shaft of the electric motor, and each end of the sleeve adapted to contact adjacent motor rotor sections. A bearing has a bore extending therethrough with the sleeve received therein. The bearing thermally locks into the stator bore early in motor warm-up and the bearing has sufficient end play on the sleeve to accommodate shaft expansion. One or more springs are located on the sleeve to bias the bearing to a neutral or generally centered position on the sleeve. The springs permit the bearing to move along the sleeve during times of thermal expansion and contraction, and prevent the bearing from becoming locked into an extreme position. This prevents the transmission of thrust loads from the rotor to the bearing.

Abstract: An elastic plane-bearing support for the impeller shaft of a water jet propulsion unit for providing good support and yet accommodating relative movement between the engine and the jet propulsion unit.