Abstract: A coiled disk spring is prepared by closely winding a strip having a noncircular cross section into a coil shape with the face inclined at a predetermined angle with respect to the axis of the coil. The sectional shape of the strip may be appropriately selected in accordance with the intended use and, for example, when it is triangular or trapezoidal, a coiled disk spring having progressive nonlinear characteristics can be obtained. A coiled wave disk spring having progressive nonlinear characteristics can also be prepared by closely coiling the strip while bending the strip into a wavy form in the circumferential direction of the coiled spring.

Abstract: Disclosed is a seismic damper for ground equipment such as high voltage breakers and disconnect switches. The disclosed seismic damper is reactive to low frequency seismic disturbances and provides damping in response to both upward and downward vertical forces. The seismic damper is adapted to be connected to such equipment without modifying the equipment. When the seismic dampers are connected to the equipment, the equipment's natural frequency in response to seismic disturbances is reduced. This reduction results from the particular use of a stacked ring compression spring and the particular configuration and assembly of the components of the seismic damper.

Abstract: A circular plate spring for use in a flexible pipe unit comprises an annular base portion constructed of a spring metal plate and a plurality of equally spaced resilient support portions integral with the annular base portion. The resilient support portions are raised from the annular base portion so that each support portion is inclined relative to an imaginary plane on which the annular base portion lies.

Abstract: The conical disc spring column has a central shaft with retention shields at both ends thereof and with aligned superposed conical discs positioned about the shaft, the shaft being formed of two coaxial telescopic sections having a sliding connection therebetween for controlled retraction and extension of the shaft.

Abstract: The invention is directed to a damped brake rod for use in an aircraft landing gear, the landing gear comprising a strut and a wheel and brake assembly carried on the strut. The brake rod connects the wheel and brake assembly to the strut and bears an axial load during braking. The brake rod is laterally damped to dissipate lateral vibrations imparted to the brake rod during braking.

Abstract: A spring unit for installation in a pivot pin assembly. The spring unit including a pair of disc springs each with an axially centered aperture and each with, when in an uncompressed condition, a concave side and a convex side. A retaining element, such as an adhesive, retains the disc springs to a returning member such that the spring unit can be easily installed in the pin assembly as a unit. The spring unit further includes a centering structure whereby the disc springs can be centered about the pin assembly when fully compressed.

Abstract: A washer faced spring assembly is disclosed for a motion absorbing and motion damping application which includes a first washer having a circular or polygonal hole therethrough centered about a central axis, a second washer disposed opposite to the first washer also having a circular or polygonal hole therethrough centered about a central axis disposed generally coincident with the hole of the first washer, and a spring connected between the first washer and the second washer, the spring including a plurality of fingers providing planar or full surface contact between the first and second washers. The washer faced spring assembly may also include a base portion utilized in conjunction with the plurality of fingers, where the base portion has one of several alternative shapes, such as circular or polygonal.

Abstract: A method for maintaining alignment of a stack of spring washers mounted on a shaft. A retainer (44) is provided with an opening (41) for mounting on a shaft (49), a planar surface (42) for contacting outer contact edge (46) of spring washer (47) and a retaining lip (43) for limiting the lateral movement of spring washer (47).

Abstract: An interlaced wave spring is formed from two constituent wave springs of similar thickness, amplitude and frequency. The two constituent wave springs are combined together by interlacing them so that the spring turns of each spring abut each other for substantially the entire length of the interlaced spring. This interlacing effectively increases the thickness of the spring turns of the interlaced spring to thereby provide increased loading and greater fatigue resistance characteristics.

Abstract: A circular multi-wave composite compression spring is formed from a carbon fiber reinforced laminate. The circular compression spring is comprised of unidirectional graphite fibers encased in a polymeric resin of generally rectangular cross-section such that adjacent crests and troughs of the waves in adjacent turns of the spring contact each other along a radial line generally extending from the longitudinal axis of the spring. The line contact provides for increased fatigue life and more stable loading of the spring under compression. The carbon fiber reinforced laminate provides comparable strength characteristics similarly configured springs fabricated from conventional materials while providing significantly reduced weight. Furthermore, the composite spring offers increased performance parameters such as increased linearity response over a wider spring deflection range and with insignificant hysteresis.

Abstract: An energy absorbing system for controlling the force where a moving object engages a stationary stop and where the system utilized telescopic tubular members, energy absorbing diaphragm elements, force regulating disc springs, and a return spring to return the telescoping member to its start position after stroking. The energy absorbing system has frusto-conical diaphragm elements frictionally engaging the shaft and are opposed by a force regulating set of disc springs. In principle, this force feedback mechanism serves to keep the stroking load at a reasonable level even if the friction coefficient increases greatly. This force feedback device also services desensitize the singular and combined effects of manufacturing tolerances, sliding surface wear, temperature changes, dynamic effects, and lubricity.

Abstract: A lightweight, high performance, active suspension system utilizing piezoelectric regulated springs, and a method of manufacturing the suspension system, is described. Piezoelectric material is bonded to suspension springs, and excited appropriately to vary the stiffness of the suspension system. A method of controlling the stiffness of a spring includes piezoelectric material bonded to the spring, a sensor system for generating a signal proportional to the loading imposed on the spring, and controller for exciting the piezoelectric material in response to the signal. A control system for controlling the stiffness of a spring including embedding a plurality of piezoelectric particles within an electrically conductive matrix forming the body of the spring is also described.

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: A constant tensioning device in the form of an elastic member interposed in the handbrake chain between a railway car handwheel and a handbrake lever of the railway car brake apparatus for maintaining tension in the handbrake chain in accordance with the applied handbrake force, irrespective of such shifting of the railway car relative to its truck, as would otherwise cause slack to develop in the handbrake chain and thereby cause an undesired loss of handbrake force.

Abstract: A film coater for applying a coating material to selected areas on a target substrate, such as a printed circuit board, having a vented dispenser body with a plunger moveable therein between an open and closed position. A flow of pressurized air which moves the plunger to the open position is controlled by a valve carried by the dispenser body, and a plurality of springs return the plunger to the closed position. The number of return springs is selected to provide a variable biasing force so that movement of the plunger is controlled to eliminate or at least significantly reduce hammering, tapering and drooling, particularly when the dispenser is operated intermittently.

Abstract: A liveload assembly having a stack guide with a thread on the exterior side wall, a plurality of compressible belleville washers stacked inside the stack guide, and a retainer cap having a thread on an inner side wall for matingly engaging with the stack guide to hold the belleville washers in compression. The gland follower of a fluid flow apparatus is liveloaded by placing the liveload assembly over the bolt extending upwardly from the gland follower. A nut is threaded on the bolt to contact the stack of belleville washers and the retainer cap is unscrewed to a second position on the stack guide and fixed by turning a set screw through a bore in the cap and against the side of the stack guide. Compression of the gland follower is monitored by viewing the relative movement of the stack of belleville washers through a longitudinal slot in the side wall.

Abstract: A drop-in type shifter is provided for an automotive transmission, the shifter employing one or more washer-like flat springs for spring biasing a shift stick to a predetermined position on the shifter and actuatable for changing the drive ratio of the transmission when the shift stick is pivoted. A base is adapted for mounting the shifter on the transmission. A spherical socket is disposed on the base, and a spherical ball is disposed on the shift stick, the shift stick being received in the ball for pivotally mounting the shift stick on the base. One or more flat washer-like springs are provided having an aperture through which the upper end of the shift stick extends, the washer-like spring being normally planar in an unstressed condition but being compressible into a curvilinear predetermined cross-sectional shape as installed.

Abstract: An upper mount assembly includes a pair of plates seating at least one Belleville spring. The plates are concentrically mounted about a hydraulic damper so that the Belleville spring is in series with a coil suspension spring. During use, deflection of the Belleville spring provides an additional degree of motion to reduce transmission of vibration to the vehicular body.

Abstract: A generally flat, flexible, resilient, double faced spring used in combination with a generally flat spacer with the spring having the same number of uniform protrusions on each of its flat surfaces, the protrusions on each surface being equidistant from each other. The protrusions have spherical tips which function as multiple fulcrums, a spherical tip protrusion on one side of the spring surface being precisely halfway between the spherical protrusion on the other surface such that no protrusion on one surface is exactly opposite a protrusion on the other. The essentially flat spacer is equipped with protrusion receiving recesses spaced to coincide with the locations of the protrusion on the adjacent spring. The tip of each protrusion of a spring is in alignment with a respective spacer recess so that when multiprotrusion springs are combined with a spacer, they are prevented by the recesses from laterally shifing or moving into a rotational position.

Abstract: The starting device includes a starting pinion mounted on a thrust rod and movable between a disengaged and engaged position with an internal combustion engine; a movable switching bolt located in a solenoid; a sphere mounted at an end face of the switching bolt closest to the thrust rod; a disc and a spring device arranged between the sphere and the end face of the switching bolt, the spring device being located between the disc and the end face, and a holding device for retaining the sphere on the end face of the switching bolt.

Abstract: A flanged washer spring is provided, comprising a first disk having a central opening, outer periphery, a first side and a second side, the first disk further having an annular inner flange extending axially from the first side, and an annular outer flange extending axially from the second side, wherein a radial distance from the outer flange to the central opening is greater than a radial distance from the inner flange to the central opening. The disks are normally used in pairs with the outer flanges of the disks positioned axially adjacent to each other. The springs may be used in combination with a tool, such as a drilling accelerator or jar, having an elongated tubular body having a body stop for axially retaining a spring, and an elongated mandrel slidingly mounted within the tubular body, the mandrel having a mandrel stop for axially retaining a spring, the spring comprising a plurality of stacked disks.

Abstract: A live-load device for applying a compressive force to packing or gasket material in a valve or pipe conduit junction. The device incorporates spring-washers having resilient blades for imparting a spring force. The spring force is transmitted from each blade through a ball-bearing seated at a selected one of a plurality of contact points along the blade tip. The spring constant of the device is selected by positioning the ball-bearing at a particular one of the contact points. This adjustment capability makes the spring device universally adaptable to a wide variety of valves and conduit junctions.

Abstract: A support is provided for use in a thermionic converter to support an end of an emitter to keep it out of contact with a surrounding collector while allowing the emitter end to move axially as its temperature changes. The emitter end (34) is supported by a spring structure (44) that includes a pair of Belleville springs, and the spring structure is supported by a support structure (42) fixed to the housing that includes the collector. The support structure is in the form of a sandwich with a small metal spring-engaging element (74) at the front end, a larger metal main support (76) at the rear end that is attached to the housing, and with a ceramic layer (80) between them that is bonded by hot isostatic pressing to the metal element and metal main support. The spring structure can include a loose wafer (120) captured between the Belleville springs.

Abstract: The springs in accordance with this invention comprise flat, double surfaced components of resilient, flexible material, which components have an equal number of uniform projections or protrusions on each side. The protrusions or projections are rounded or generally spherically shaped, and equally spaced one from another, with the protrusions on one surface of the flat component being precisely intermediate the protrusions on the other surface. Where protrusions are formed by a press which forms a dent in one surface, dents and protrusions alternate on each surface, whereas the side or surface of the component opposite each solid protrusion is flat. The springs are controlled by simple beam deflection. They are inexpensive to produce and may be employed in numerous systems to minimize friction, overheating, stress, fatigue or deformation, damp oscillations or vibrations and maintain alignment.

Abstract: A liveload assembly including an stack guide, compressed belleville washers stacked inside the stack guide and a retainer to hold the compressed washers in the stack guide. A longitudinal slot in the wall of the stack guide permits visual checking of the compression provided by the liveload assembly on the gland follower of the valve or pump. The rotary or reciprocating shaft of a valve or pump is liveloaded by placing the liveload assembly over the bolt securing the gland follower to the stuffing box. A nut is threaded on the bolt until it contacts the washers and the retainer removed.

Abstract: A cutting apparatus for forming a noncircular cross-section on a workpiece that includes a tool advancing and retreating device. The tool advancing and retreating device includes a central shaft on which is to be mounted a tool, a journal for supporting the central shaft, a movable plate fixed to the central shaft, and electromagnets positioned opposite to one another such that the movable plate is interposed between the electromagnets with a clearance between the plate and the electromagnets. A device is provided for detecting the rotational angle of the main shaft and a displacement sensor is included for detecting the longitudinal displacement of the central shaft. A speed sensor detects the speed of the longitudinal displacement of the central shaft and an arrangement is provided for controlling the electric current passing through the electromagnets based on the output signals from the rotational angle detecting device, from the displacement sensor and from the speed sensor.

Abstract: A flexible bearing for supporting a body, in particular, for supporting an internal-combustion engine, includes a journal bearing that may be attached to a supporting foundation and a support that may be attached to the engine. An elastic spring is connected between the journal bearing and the support while a bearing spring made of a non-creeping material is connected between the journal bearing and the support in parallel with the elastic spring. The bearing spring comprises at least one disk spring having an S-shaped spring constant curve. The disk spring and the elastic spring have load carrying capacities such that, after the weight of the body to be supported is applied to the flexible bearing, the spring rate of the disk spring is essentially zero and the rubber spring is essentially free of elastic tensions.

Abstract: A mechanical connection for providing desirable stiffness and damping of mechanical energy. The connection includes at least one frusto-conical annular disc element having a radial discontinuity extending from inner to outer peripheral edges, and a visco-elastomeric matrix on at least one annular face thereof. The cross sectional configuration of the element enables it to undergo axial displacement due to flexure of the disc as the matrix simultaneously undergoes shearing strains in generally tangential and radial directions.

Abstract: A demountable pin for rotatably connecting together two elements of small axial dimension, consisting of a bolt with a frusto-conical under-head and an inner hexagonal through bore for tightening it by a key. The pin is locked between two frusto-conical flares of the elements by an end nut with a frusto-conical under-head and a washer with a frusto-conical surface of greater taper than the flares. The under-heads of the nut and the bolt cooperate with the flares.

Abstract: A spring support system for a compliant hydrodynamic gas lubricated bearing comprises a plurality of cylindrical spring elements that are retained by floating control rods in circumferential and axially extending arrays for the support of a compliant foil.

Abstract: An arrangement which includes a coned ring forms with the coned portion an interior space. The interior space decreases and increases its volume, when the coned portion of the ring is compressed and de-compressed. The coned ring has a radial outer portion and a radial inner portion. The radial inner portion forms a bore. The radial outer portion is provided with a seat face portion. The seat face portion contacts and bears a respective portion of a body, which may be a second coned ring, a thrust body or an outer ring. The arrangement is utilized to center a coned ring relative to a neighboring body or to provide and effectively seal a working chamber for the reception and expulsion of a fluid.

Abstract: A flexible beam arrangement functioning as a valve member guide in a pressure relief valve for maintaining proper alignment of a valve member and a valve seat is disclosed wherein one end of the flexible beam is affixed to a valve housing and the other end thereof is fixed to the valve member so that opening and closing of the valve is associated with a flexing of the beam, however sliding motion of the valve member relative to the guide is eliminated. This assures an accurate reseating of the valve member on the valve seat. In the preferred form the flexible beam is formed as a relatively flat disc with an outer peripheral portion being the one end that is fastened to the housing and a central portion being the other end which is fastened to the valve member. Fastening of the other end to the valve member may be accomplished by a shoulder and snap ring arrangement so that the valve member may rotate about its axis relative to the disc, however, axial valve movement requires flexing of the disc.

Abstract: A combination of a power transmission belt that is to be operated in an endless path and a tensioner for the belt is provided, the tensioner comprising a support unit fixed relative to the belt, a belt engaging unit carried by the support unit and being movable relative thereto, and a mechanical spring unit operatively associated with the support unit and the belt engaging unit urging the belt engaging unit relative to the support unit in a belt tensioning direction and against the belt with a force to tension the belt, the spring unit being arranged to increase its urging force on the belt engaging unit as the belt engaging unit moves in the belt tensioning direction relative to the support unit throughout the entire normal tensioning range of movement of the belt engaging unit relative to the support unit.

Abstract: A force limiter to be interposed between an actuator and a device to be moved by the actuator to limit the force applied by the actuator. The force limited has a body having a chamber and open at at least one end. There is a piston slidable within the body. A piston rod extends from the piston through, and slidable within, the open end of the body. Resilient members such as Belleville washers are positioned in the chamber between the piston and an end of the chamber away from the piston. The resilient members are calibrated to provide the necessary force limit and are able to apply that force limit in both directions of movement of the actuator. The force limiter can be attached to the actuator.

Abstract: The kinetic energy generated by the rapidly moving contact and coupled operating mechanism of a tripped circuit breaker or similar apparatus is dissipated by a compressible shock-absorbing assembly comprising a loose stack of metal plates and interposed springs which is mounted on a stationary part of the breaker and is struck by a lever fastened to the main operating shaft of the breaker operating mechanism. The metal plates are movable toward and away from one another due to the resiliency of the springs and the resulting multiple impacts between the plates and advancing striker lever produces a momentum exchange phenomenon which quickly dissipates the kinetic energy and brings the breaker operating mechanism and movable contact to a smooth stop. The compressible multiple-impact assembly provides a compact shock absorbing means that is especially adapted for use in medium voltage circuit breakers (5 to 35 KV rating) of various types which is not only durable and efficient but very inexpensive and reliable.

Abstract: A drop-in type shifter for an automotive transmission is provided that is spring biased with relatively flat washer-like springs. The shifter comprises an elongate shift stick having an upper end and a lower end. The upper end is manually actuable and the lower end is adapted for insertion in an automotive transmission for changing the drive ratio of the transmission when the shift stick is pivoted. A base is provided for mounting the shifter on the transmission and a spherical socket is disposed on the base. A spherical ball is disposed on the shift stick between the upper and lower ends of the shift stick and the ball is received in the spherical socket for pivotally mounting the shift stick on the base. A channel is provided which bisects the socket. The ball is provided with a rocking shaft having first and second ends disposed on adjacent sides of the ball and extending into the channel for stabilizing the pivotable shift stick for pivotable movement about first and second orthogonal axes.

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

Abstract: First and second structures are hingedly connected by the engagement of a hinge pin (24) by a hinge knuckle (22). Knuckle (22) is rigidly mounted on the first structure. Pin (24) is attached to a carrier that is slidably mounted on the second structure. A spring, preferably a plurality of stacks of Belleville springs, is positioned between the carrier and the second structure. The slidable mount allows the two structures to move translationally relative to each other to prevent excessive hinge loads. The spring controls such movement and biases the hinge pin, and therefore the hinge axis, into a center position.

Abstract: A tensioning device for chains such as tensioning chains, sling chains, tire chains and the like with a tensioning unit having at least one tensioning spindle which is connected with a tensioning nut and having at least one damping spring. The damping spring is a cup spring package and the cup spring package is installed in the tensioning unit. A multiplicity of the cup springs of the spring package can have a single layer and the remaining cup springs can have multilayer arrangement. More than half of the spring path, preferably approximately 80% of the entire spring path of the spring package is preloaded with a half force which is at least smaller by approximately one half than the preloading force of the remaining spring path. A control device has an indicator connected with a tensioning spindle and this indicator such as a bolt is movable, preferably is journalled longitudinally shiftable in a housing opening.

Abstract: A drill string splined resilient tubular telescopic joint for balanced load deep weel drilling comprises a double acting damper having a very low spring rate upon both extension and contraction from the zero deflection condition. Stacks of spring rings are employed for the spring means, the rings being either shaped elastomer-metal sandwiches or, preferably, roller Belleville springs. The spline and spring means are disposed in an annular chamber formed by mandrel and barrel members constituting the telescopic joint. The chamber containing the spring means, and also containing the spline means, is filled with lubricant, the chamber being sealed with a pressure seal at its lower end and an inverted floating seal at its upper end.A prototype includes of this a bellows seal instead of the floating seal at the upper end of the tool, and a bellows in the side of the lubricant chamber provides volume compensation.

Abstract: A torque transmitting drill string tool is provided that includes an outer member and an inner member telescopically arranged. Spline means between said outer member and said inner member transmits torque. A spring means is positioned between the outer member and the inner member. Means are provided for adjusting the position and/or pre-load of the spring means without disassembling the tool.

Abstract: A drill string splined resilient tubular telescopic joint for balanced load deep well drilling comprises a double acting damper having a very low spring rate upon both extension and contraction from the zero deflection condition. Preferably the spring means itself is a double acting compression spring means wherein the same spring means is compressed whether the joint is extended or contracted. The damper has a like low spring rate over a considerable range of deflection, both upon extension and contraction of the joint, but a gradually then rapidly increased spring rate upon approaching the travel limits in each direction. Stacks of spring rings are employed for the spring means, the rings being either shaped elastomer-metal sandwiches or, preferably, roller Belleville springs. The spline and spring means are disposed in an annular chamber formed by mandrel and barrel members constituting the telescopic joint.

Abstract: A double acting damper for use in rotary drilling includes a splined tubular telescopic joint and employs plural paralleled stacks of double acting series stacked roller Belleville spring washers in an annular pocket between the inner and outer tubular members of the joint. The springs, spline and telescopic bearings are in an oil filled volume sealed from the outside by a pressure seal at the lower end of the damper and a floating seal at the upper end. Electric and magnetic means are provided to check on the condition and quantity of the lubricant.

Abstract: An isolator designed to prevent transmission of shock and vibration from one structure to another, comprising a device structured to provide orthogonal excursion in three directions and comprising a plurality of nested, concentrically-arranged component structures, each of which is structured to permit orthogonal excursion and a connector element for securing structures in nested parallel relation so that the composite resistance to displacement is the sum of the resistances of the individual components. The component structure may decrease in size from the outside to the inside or be all of the same size.

Abstract: There is disclosed a shock sub for incorporation in the lower part of a drill string for damping oscillations of the bit and drill string during drilling. The shock sub incorporates a spring assembly including a multiplicity of substantially annular ring springs that exhibit a spring rate of less than about 25,000 pounds per inch of deflection. This is a continuation of application Ser. No. 849,718, filed Nov. 8, 1977 now abandoned.

Abstract: An operating mechanism for a hinged deck portion of a vehicle-carrying auto-rack railway car utilizing a first-class lever to counterbalance the deck end portion. A spring load is provided by a Belleville spring pack of novel, compact construction which has a substantially constant spring-force versus deflection curve such that manual manipulation of the hinged deck by operating personnel is facilitated during loading and unloading of the auto-rack car.

Abstract: In a load system which involves a powered chain hoist wherein raising or lowering of a load is effected by a rotating drive sprocket over which the chain is trained, the amplitude of motion due to resonant response of the load system as a consequence of coincidence between the natural frequency of the load system and the frequency of oscillatory excitation produced by the chain/sprocket drive is significantly reduced by providing an energy dissipation device in series with the load. This device involves a spring mechanism which permits a limited motion at the resonant condition, in combination with a controlled damping factor. The spring compliance of the device normally will lie in the range of about 1/2-3 times the spring compliance of the active length of the chain at the resonant condition and the relation between the spring rate of the device and the effective damping factor is perferably such that the spring rate divided by the damping factor will be at least about 0.006 seconds.

Abstract: Linear acceleration responsive apparatus is disclosed wherein a sensing mass is suspended within a housing by torsion hinge means located along a pair of parallel axes in each of two planes perpendicular to an input axis. Separate torsion hinge means in each plane are attached to the mass and the housing by ring assemblies, and are joined by intermediate arms which may serve as flex leads for carrying electric current to a force rebalance winding on the mass.

Abstract: A steering clutch and brake power drive assembly wherein a clutch pack and a brake pack formed of a plurality of facially engageable plates are respectively retained between a retaining plate and a housing portion of the assembly by a plurality of bolts which, in the assembled arrangement, provide a preselected stress in biasing springs acting on the clutch plates and brake plates, respectively. A novel arrangement of bolts is provided wherein different size bolts are utilized for facilitating the assembly and disassembly. A small number of the bolts is made to be sufficiently large so that the assembly may be maintained by a single one thereof notwithstanding a high biasing force generated by the spring in the assembled arrangement. An improved lubrication oil transfer structure is further provided to the plate stack from a pressurized oil supply defined by a lubricating oil cavity adjacent the plate stack.

Abstract: A power drive assembly having a housing, a drive mechanism removably installed in the housing, an annular biasing spring installed in the housing for biasing the mechanism, and a wear ring arrangement including an undercut annular groove in the mechanism opening coaxially toward an end of the biasing spring and a wear ring removably installed in the groove to engage the end of the biasing spring in the assembled arrangement of the power drive assembly. The wear ring has a cross section complementary to the undercut groove cross section whereby the mechanism may be installed in the housing with the groove opening downwardly and the wear ring maintained in the groove for facilitated assembly of the power drive.