Abstract: An improved parking brake system for a vehicle capable of switching the operation of the parking brake between an automatic control mode and a manual control mode at the operator's will. The parking brake is applied and released by an electromagnetic device which is controlled by a brake-application command signal and a brake-release command signal produced by a controller. The controller is adapted to be manually switched between a manual brake-application and brake-release control mode and an automatic control mode under the action of a switch. A power supply circuit is provided which has a battery and an ignition power source for supplying power to the electromagnetic device.

Abstract: An automatic locking gear is adapted to drivingly connect a drive axle and wheel hub automatically in response to application of torque to the drive axle which has a stationary housing in which said drive axle is journaled, a drive gear keyed for rotation with the drive axle while being slidable in an axial direction independently of the drive axle, and a driven gear is keyed for rotation with the wheel hub while being slidable in an axial direction independently of the wheel hub. The locking member is mounted on the stationary housing, and the cam follower mounted on the drive gear.

Abstract: A mechanism for machining an object, such as a key blank, to a desired shape at a plurality of successive positions in an axial direction of the object, includes a holder for the object. The holder is axially movable by means of a transfer mechanism with a rotatable shaft. There is a feeder member connected to the rotatable shaft and cooperating with a clutch device axially stationary relatively to the holder. Cooperating guiding surfaces are arranged to transmit to the holder an axial movement during a limited turning of the rotatable shaft. This turning is only a small portion of a full turn of the rotatable shaft. The machining of the object takes place as a continuous guided operation during such a turning of the rotatable shaft which is separate from the turning thereof causing the holder to move axially.

Abstract: An apparatus for positively engaging and releasing a roller clutch actuator in a two-way overrunning roller clutch system 10 includes an actuator ring 54 having a plurality of detents 58 for receiving a radially extending, reciprocably moveable plunger 60. In a preferred form, the roller clutch drive system includes an axle case 38 containing a complimentary pair of drive and driven rotary members. The drive member 46 includes an axially extending bore, and the driven member 48 has one end thereof disposed within the bore. The drive and driven members together define an axially extending annulus 51 which contains a plurality of axially oriented rollers 42 circumferentially contained therein by a cage 50. The cage maintains the rollers in uniformly spaced relationship, and includes a friction ring 52 preferably integral therewith. The actuator ring surrounds the friction ring in constant, resilient, frictional engagement therewith.

Abstract: A drive shaft is connected with one coupling half of a synchronizing tooth clutch and with a primary part of a fluid coupling. A driven shaft is connected with another clutch half of the tooth clutch and with a secondary part of the fluid coupling. The tooth clutch has a clutch star which is axially displaceably guided by a first straight tooth system at the one clutch half by continuous tooth mesh and can be engageable with a second straight tooth system provided at the second clutch half. Threadably connected with the second clutch half a is also connected by a ratchet with the clutch star and is conjointly axially displaceable therewith. The ratchet engages and causes a screw-like relative movement of the screw socket in relation to the second clutch half causing of the clutch star to engage, when the rotational speed of the first clutch half, in normal forward rotation, is about to fall below the rotational speed of the second clutch half.

Abstract: A recoil starter mechanism (10) mounted in axial alignment with the flywheel (12) of an internal combustion engine has a drive plate (16) with clutch teeth (34) which moves axially when rotated to engage clutch teeth (17) on the flywheel and rotate the flywheel (12) to start the engine. The drive plate (16) is driven axially and rotationally by ramps (30) on the starter pulley (14) when the starter rope (24) is pulled. A brake plate (18) frictionally engaging the starter housing (13) has arms (37) engaging the drive plate to resist rotation of the drive plate (16), thereby forcing the drive plate to move axially as the starter pulley (14) is rotated.

Abstract: A valve operator has a de-clutch mechanism for automatically shifting the clutch out of handwheel drive and into electric motor drive upon actuation of the electric motor. The motor drive sleeve 23 has an annular step 25 which has a flat 26. The clutch 50 is biased by spring 55 toward the motor drive sleeve 23 but is prevented from moving in the direction of the motor drive sleeve by the clutch fork 40 which has extending therefrom two latch arms 71,72 one of which 71 is longer than the other 72. The longer latch arm 71 abuts against the step 25 on the motor drive sleeve. When the electric motor M is energized, the motor drive sleeve rotates and the flat 26 comes into alignment first with the longer latch arm 71 and later with the shorter latch arm 72, thereby releasing in two steps the clutch fork 40 and allowing the clutch 50 to shift out of handwheel drive and into electric motor drive.

Abstract: An automatic hub clutch used for connection and disconnection of a drive axle with a wheel of a four-wheel drive vehicle, has a simple mechanism and a short axial length. The hub clutch includes a first spring adapted to bias a slide gear toward disengagement, and a second spring disposed radially inwardly of the slide gear and adapted to bias the slide gear toward engagement through a cam.

Abstract: An electromagnetic spring clutch comprises a driving member, to be driven by a belt, and a driven member, which is connected to a load shaft, and to which revolving power is to be transmitted from the driving member by a clutching coil spring.One end of the coil spring is fixed to the driving member and the other end is fixed to a rotor which is freely rotatable and has several rotor windings, each shortcircuited.A stator having several windings to be excited by a power source is disposed closely parallel to the rotor for electromagnetically braking it, to thus twist the coil spring and make it grip the driven member.

Abstract: An automatic hub clutch used for connection and disconnection of a drive axle with a wheel of a four-wheel drive vehicle includes a simple mechanism having a short axial length. The hub clutch includes a first spring adapted to bias a slide gear toward disengagement, and a second spring disposed between and coaxially with the first spring and the slide gear, and adapted to bias the slide gear toward engagement through a cam.

Abstract: An automatic clutch disposed between driving and driven members comprises, on the driving side, a drive clutch movable only axially relative to other parts and normally biased in the declutching direction, an outer cam located on the side where the drive clutch is biased and moved, the cam being adapted to move in the same way as the drive clutch, with a spring disposed between the outer cam and the drive clutch to bias them away from each other, and a stationary inner cam adapted to be connected to or disconnected from the outer cam according as the clutch disengages or engages, the inner cam having projections. A holdout ring has projections to be engaged with the projections of the inner cam and adapted to keep the outer and inner cams out of connection when the driving side stops, the holdout ring being fitted over the outer cam under such frictional conditions that, only when the ring has engaged the inner cam, it can circumferentially slide relative to the outer cam.

Abstract: A magnetically actuated clutch in which a helical spring is carried by an input clutch member with portions surrounding a relatively rotatable output clutch member. An electromagnet is positioned with its poles lightly engaging the surrounding spring portions at circumferentially spaced locations, while either the spring or the output clutch member or both are formed of a magnetically permeable material to complete a magnetic circuit. Energizing the electromagnet causes the poles to clamp the spring to retard its rotation with the input member, thereby causing the spring to wrap down on the output clutch member and engage the clutch.

Abstract: Pilot torque is transmitted from the input member to the output member of a clutch when a shoe is pressed axially against the input member. When initially turned by the input member, the shoe causes a helical spring to wrap down on angularly spaced shoe segments and to contract the shoe segments into radial gripping engagement with the input member. The shoe segments engage angularly spaced drive lugs on the output member to transmit torque to the output member.

Abstract: An improved clutch of the type having concentric and spaced apart driving and driven members with a clutch ring in engagement with one of the members and urgeable into a simultaneous engagement with the other member is provided. A fixed cam member is provided nonrotational with respect to the driving and driven members. A second cam member is slidably movable around the first cam member whenever the clutch ring is in simultaneous engagement with the driving and driven members. A cam follower is in a cammed engagement with the first cam member and is movable axially apart from the first cam member into cammed engagement with the second cam member. The cam follower further urges the clutch ring into a simultaneous engagement with the driving and driven member whenever the driving member rotates with respect to the driven member.

Abstract: A wrap-down spring clutch includes a drum and a spring which are selectively engaged by a solenoid. The solenoid has a coil, which when energized, extends a ferromagnetic plunger. When the coil is energized the plunger is extended out against the spring and urges the same into frictional engagement with the drum. The drum is also ferromagnetic, such that the activation of the coil simultaneously magnetizes the plunger, and creates a magnetic attraction between the plunger and the drum which further urges the plunger against the spring and the drum to produce a wrap-down pressure which effects quick and secure clutch engagement.

Abstract: A free wheel hub mechanism made up of a body secured to a wheel, an inner race secured to an axle shaft and rotatable therewith, means for engaging the inner race with the body only upon rotation of the shaft and for otherwise permitting free rotation of the body. A shoe receiving member is secured to a spindle sleeve of the axle shaft and has a receiving surface which crosses the axle shaft at substantially a right angle. A shoe means maintains the engaging means in its engaged condition, the shoe means having a sliding surface which crosses the axle shaft at a substantially right angle, and a spring biases the sliding surface of the shoe means against the receiving surface of the shoe receiving member.

Abstract: A vehicle drive system particularly suited for snow blowers includes a main sprocket rotatably carrying a first and second pawl. Each pawl drivably engages a respective sprocket. The first sprocket is fixably mounted to a first axle means such that rotation of the main sprocket causes the first pawl to drivably engage the first sprocket to rotate the first axle means. A second sprocket is fixably engaged to a second axle means such that rotation of said main sprocket causes a second pawl to drivably engage the second sprocket to cause rotation of the second axle means. Friction means supplies sufficient drag to the pawl such that rotation of main sprocket causes each of the pawls to assume an engaging orientation with their respective sprockets. Each of the pawls can be selectively disengaged from a drive orientation by manually advancing the respective axle means, i.e., when an operator maneuvers the vehicle for turning.

Abstract: Torque is transmitted from the input member of a clutch to a primary shoe when the primary shoe is pressed into frictional engagement with the input member by compression springs. When initially turned by the input member, the primary shoe moves a series of balls angularly along inclined ramps to cause a secondary shoe to shift into frictional engagement with the input member and transmit torque to the output member of the clutch. A brake acts through the shoes to retard the output member when the clutch is disengaged.

Abstract: A clutch for automatically engaging a driving member with a driven member upon application of torque to rotate the driving member in either direction, for maintaining engagement in either the drive or coast mode of operation and during the transition between drive and coast, for maintaining engagement in either the forward or reverse mode of operation, and for disengaging automatically upon interruption of the torque and slight rotation in the opposite direction.

Abstract: An overrunning clutch made up of an input member and an output member with locking means between them for positively locking the two members together and a racheting member on the input for moving the locking member from a position to positively lock the input member to the output member when the input member rotates at a higher speed than the output. The clutch has an improved mechanism for engagement of the drive and driven parts.

Abstract: This is a combination accelerator and brake control mechanism wherein there is a single pedal serving both as the gas control and the brake control. The single pedal is pivoted on a pivot fixed in a base, the pedal extending through the vehicle floor board. Pressing with the foot on the superior or upper part of the single pedal controls the gas to the vehicle motor, pressing with the foot on the lower or inferior part of the pedal controls the brakes of the vehicle. A see-saw rod contacts directly or indirectly with the ends of both the vehicle gas control rod or the brake control rod, and the motion of the pedal pressed down on its top end acting through the see-saw rod moves the gas control rod from neutral position to gas control position, and pressing the lower end of the pedal actuates the brake control rod.

Abstract: Input and output member (21), (28) and a clutch disc (32) are coaxially rotatable relative to each other, the clutch disc (32) being frictionally engageable with the input member (21). A coil-wound spring (33) is wound around the input member (21) and connected at its ends to the clutch disc (32) and output member (28). An electromagnetic coil (26) may be energized to attract the clutch disc (32) into frictional engagement with the input member (21), causing the coil-wound spring (33) to tightly wind around the input member (21) and drivably connect the input member (21) to the output member (28). A generally tubular cover (34) surrounds the coil-wound spring (33), the spring means (40) moving the clutch disc (32) toward engagement with the cover (34) when the coil (26) is de-energized.

Abstract: This invention is an overrunning tooth type clutch which is retarder controlled. The clutch engages and disengages two axially aligned shafts with slight relative rotation. The retarder comprises a wrap spring which is circumferentially mounted on the driven shaft and engages the driving shaft. Relative shaft rotation in one direction causes the spring to drag on the driven shaft. In this mode, a force is created in the axially inclined slot through a pin on the driving shaft which causes the driven clutch member to move axially to engage the clutch on the driving shaft. Opposite relative rotation causes the clutch teeth to separate and disengage the two clutch members for slip or overrunning.

Abstract: A disconnect for disengaging an accessory rotor from a driving engine and quickly decelerating the accessory rotor to a stop.

Abstract: A differential gear mechanism of the limited slip type is provided. The mechanism includes a clutch, including a plurality of discs (31 and 33), and a cam mechanism including a main cam member (43) and an intermediate cam member (45). The intermediate cam member is splined to the side gear (19), such that axial forces are not transmitted to the side gear. The main cam member (43) defines a set of internal gear teeth (81), engaging an externally toothed member (79) of an acutating mechanism (71). The arrangement of the cam members and the provision of the gear teeth on the inner periphery of the main cam member results in a differential gear mechanism having a substantially reduced "bearing span", combined with a reduced casing diameter.

Abstract: Spring clutch is actuated by magnetic field applied radially between non-rotatable source and rotative clutch hub and spring-contracting ring.

Abstract: Input and output members (19), (28) and a clutch disc (32) are coaxially rotatable relative to each other, the clutch disc (32) being frictionally engageable with the input member (19). A coil-would spring (33) is wound around the input member (19) and connected at its ends to the clutch disc (32) and output member (28). An electromagnetic coil (26) may be energized to attract the clutch disc (32) into frictional engagement with the input member (19), causing the coil-wound spring (33) to tightly wind around the input member (19) and drivably connect the input member (19) to the output member (28). A spring (41) quickly and smoothly disengages the clutch disc (32) from the input member (19) when the coil (26) is de-energized. A plurality of pins (36) extending through the clutch disc (32) ensure parallel movement of the clutch disc (32) toward and away from the input member (19).

Abstract: A clutch interposed between a hub mounted for rotation on a spindle and a selectively driveable axle which extends longitudinally through the spindle serves to engage the hub to the axle when the clutch is subjected to torque caused by placement of the axle in a dynamic or driving axle mode. When the axle is in a passive or non-driving axle mode the clutch serves to disengage the hub from the axle whereby the hub is free-wheeling on the spindle.

Abstract: A vehicle braking system including a wheel hub, a hub member separate from the wheel hub, a torsional coupling device and a magnetically actuable brake spring. In a preferred embodiment, the hub member is connected to the vehicle suspension by the torsional coupling device and, upon actuating, the brake spring wraps around the wheel hub to cause the hub member and the wheel hub to be nonrotatably joined together. In another embodiment, the wheel hub is torsionally connected to the hub member and actuation of the brake spring causes the hub member to be nonrotatably joined to the vehicle suspension. The movements of the wheel hub relative to the vehicle suspension permitted by the torsional coupling are monitored by an electronic control circuit that guards against wheel lockup or skid conditions. The electronic control circuit intermittently triggers the brake spring between brake release and approaching wheel lockup so as to incorporate anti-skid performance with the brake function.

Abstract: The hand drive employs two coil springs between the sleeve of the coupling and the shaft to be turned. The hand wheel has a driver with a parallelepiped extension for abutting one or the other of the facing spring ends depending on the direction of rotation of the hand wheel. A brake is also used to restrain movement of the sleeve and limit the torque exerted on the sleeve by the hand wheel.

Abstract: A remotely operable drive coupling for selectively engaging and disengaging a driving shaft and a driven shaft operable in accordance with the direction of shaft rotation. The coupling comprises a splined axially movable member connected to the driven shaft and having a screw-threaded bore, and a screw-threaded terminal part on the driving shaft adapted to be threadably received in the threaded bore when the driving shaft is rotated in one direction and the axially movable member is urged toward and in engagement with the terminal part of the driving shaft coupling the two members. Upon rotation of the driving shaft in the opposite direction, the parts become unscrewed and the axially movable part is resiliently urged away from the driving shaft uncoupling the members.The device can be controlled hydraulically, pneumatically or electrically.

Abstract: An electromagnetic clutch wherein a rotational force is transmitted between a first rotatable member and a second rotatable member by a magnetic attraction of an armature supported on one of the first and second rotatable members to the other member. The armature is rotatable with respect to the member upon which it is mounted within a limited extent. At least one arcuate spring member is provided to connect the armature and the supporting member. The inner surface of the arcuate member faces the annular surface of a portion of the other rotatable member. When the armature is magnetically attracted to, and rotated together with, the other rotatable member, the inner surface of the arcuate spring member comes into contact with an annular surface of the other rotatable member so that the transmission of the rotational force is effected through the arcuate spring in addition to the magentic attraction of the armature.

Abstract: A free wheel hub apparatus for vehicles having a wheel hub and an axle shaft includes a body integrally rotated with the wheel hub, an inner member disposed within the body and integrally rotated with the axle shaft, a bearing member interposed between the inner member and the body, a plurality of rollers interposed between the inner member and the body, a cage for supporting the rollers, and frictional means for engaging or disengaging the cage with or from a knuckle or the body according to the axial movement of the cage by a handle.

Abstract: A free wheel hub mechanism is made up of a body secured to a wheel and an inner race rotatable with an axle shaft and having a plurality of cam surfaces at its outer periphery, a plurality of rollers held by a cage arranged between the body and the inner race, the rollers being urged ouwards by the cam surfaces so as to be squeezed against the body when the inner race is rotated with the shaft. The squeezing of the rollers causes them to rotate with the inner race thereby to rotate the wheel. Also provided are means for restraining the rotation of the cage, including a plurality of shoes between which a plurality of projections provided on an innermost portion of the cage are arranged, a shoe receiving member secured to a non-rotatable spindle sleeve which houses the shaft and which has a receiving surface on which the shoes may slide, and an annular spring means urging the shoes against the receiving surface.

Abstract: Rotary input and output members (19), (28) are axially aligned with each other and a rotary clutch disc (32) is axially aligned with and frictionally engageable with the input member (19). A coil-wound spring (33) is wound around the input and output members (19), (28) and connected at its ends to the clutch disc (32) and output member (28) respectively. An electromagnetic coil (26), which energized, attracts the clutch disc (32) into frictional engagement with the input member (19) and causes the coil-wound spring (33) to tightly wind around and embrace the input and output members (19), (28), thereby drivingly connecting the same together.

Abstract: A delay mechanism for providing a delay in the spin cycle of an automatic washer is operated by means of a pawl pivotable about a stud rotating on an eccentric, which in turn is engageable with a spin gear only in one direction of rotation, and thereby provides a delay of substantially one revolution of the eccentric upon a change in direction of rotation of the eccentric.

Abstract: An electromagnet for brakes and clutches having outer and inner poles and an electrical coil for creating a magnetic field between these poles is provided having a circumferential gap in the forward portion of the outer pole. The gap reduces the flux density over the forward portion of the magnet face while increasing the flux density over the rearward portion. The variable flux density over the magnet face thus establishes an unbalance of forces attracting the magnet toward the armature plate causing the magnet to engage the armature plate heel first thereby eliminating "squeal" caused by magnet gouging and two plane wear of the magnet's friction face.

Abstract: The blades of a rotary lawn mower are driven by a constantly rotating shaft through a clutch-brake assembly which, when the operator leaves the operating station of the mower such as the mower handles, automatically disengages the blades from the shaft and brakes the blades while permitting the shaft to continue to rotate. The clutch-brake assembly is self-energizing and normally is engaged but is held in the disengaged condition by an actuator which also is self-energized and which initially is energized by a spring. The latter is effective to disengage the clutch and actuate the brake thereby to prevent the blades from rotating until the operator moves a manual member at the operating station to overcome the spring which initially energizes the actuator. This de-energizes the actuator so that the brake is disengaged and the clutch is engaged whereby the shaft rotates the blades.

Abstract: Torque is transmitted between the driving and driven members of the clutch by a helical spring and a friction shoe. When an electromagnet is excited, pilot torque is applied to the spring to cause the spring to clamp downwardly around the shoe and cause the shoe to contract radially around the driving member and transmit torque to the driven member. The driving member, the driven member, the spring and the friction shoe are arranged in such a manner that the spring effects soft engagement of the clutch while amplifying the pilot torque sufficiently to enable a relatively small and light weight clutch to produce ample output torque.

Abstract: Input and output members and a clutch disc are coaxially rotatable relative to each other, the clutch disc being frictionally engageable with the input member. A coil-wound spring is wound around the input member and connected at its ends to the clutch disc and output member. An electromagnetic coil may be energized to attract the clutch disc into frictional engagement with the input member, causing the coil-wound spring to tightly wind around the input member and drivably connect the input member to the output member. A spring means quickly and smoothly disengages the clutch disc from the input member when the coil is de-energized. A plurality of pins extending through the output member and the clutch disc ensure parallel movement of the clutch disc toward and away from the input member.

Abstract: A free wheel hub device made up of a main body secured to a wheel; an inner race secured to a wheel axle and rotatably supporting the main body at its outer periphery; a toothed wheel axially mounted on the inner race and having a cam face and outer teeth engageable with inner teeth of the main body; a spring located between the inner race and the toothed wheel; a support member secured to the wheel axle tube and connected to the axle; and a shoe located between the toothed wheel and the support member, and having a cam face engageable with that of the toothed wheel. The shoe is rotatable on a guide surface of the support member so that, upon engagement of the cam faces, the outer teeth of the toothed wheel engage with the inner teeth of the main body, against the force of the spring, to slidably rotate the shoe upon the guide surface of the support member.

Abstract: A deceleration controlled and limited brake incorporates a deceleration sensor to limit the amount of braking torque which can be manually applied to a disc type brake. The deceleration sensor is a weighted lever which responds to deceleration by tending to disengage a disc clutch which the activated normal brake lever is engaging. The clutch force is applied at the end of a lever to provide the torque to engage the disc brake and provide deceleration of the vehicle containing the disc brake. Mechanical advantage together with deceleration control is provided by this clutch-brake assembly.

Abstract: A braking device for a remote actuation system includes a plurality of balls or rollers interposed between a surface of a rotary member and a notched external surface of a housing. A cage for the balls or rollers is frictionally engaged with the rotary member so that when the case is free, it rotates with the rotary member and the balls or rollers moving in their notches thereby brake the rotary member. An electromagnetically operable device is coupled to the cage so that when energized it holds the cage in a central position so that braking does not then occur.

Abstract: An over running clutch having a ball that wedges against the interior of a circular race to move a pawl into engagement with a ratchet.

Abstract: A clutch device interposed between a driving shaft 1 and a drum 2-4 rotatably mounted thereon to drive frictionally a yarn winding bobbin in a spinning, twisting or doubling frame comprises a cylindrical sleeve 5 carried by shaft 1, a string 6 wound on sleeve 5 and having one end attached to the hub 2 of drum 2-4, a plate 9 slidable on shaft 1 and to which the other end of string 6 is attached, a frictional abutment ring 11 secured to shaft 1, a spring 10 to apply plate 9 against ring 11, and a pusher 14 by means of which plate 14 may be moved apart from abutment 11 to de-clutch drum 2-4 from shaft 1. A frictional lining 13 is disposed on ring 11 to enhance its driving effect on plate 9 to more tightly wind string 6 on sleeve 5. Another frictional lining is provided on pusher 11 to act on plate 9 when the latter is disengaged from ring 11.

Abstract: A two-way overrunning clutch is automatically conditioned for operation in either direction of rotation. A plurality of spaced drag springs are in frictional contact with the clutch housing so as to provide balanced radial drag forces on the wedging elements of the clutch, thereby biasing the clutch toward an engaged position thereof. This frictional contact with the clutch housing is reduced by balanced dynamic friction forces developed upon rotation of the clutch.

Abstract: An environmentally protected momentum type, electrically controlled torque producing device consisting of a driving member provided with a multiple of driving shoes with friction lining faces, connecting arms constructed in a manner to hold shoes from engagement with driven member except upon energization of the electrical coil which in turn causes armature to force shoes in an outwardly direction into engagement with the inner periphery of the driven member. Contractile springs are provided to retain driving shoes in the disengaged position while the unit is at zero rotation.

Abstract: A coupling for controlling or limiting the angular velocity or angular acceleration between first and second rotatable members. The coupling has an enclosure containing viscous liquid in which first and second sets of interleaved elements and third and fourth sets of interleaved elements are arranged for rotation about a common axis. The first and third sets of elements have driving connections with the first rotatable member and the second and fourth sets of elements have driving connections with the second rotatable member. Spacing means are provided to space apart the facing surfaces of adjacent elements of at least one of said first and second sets and also at least one of said third and fourth sets so that the facing surfaces of adjacent elements of each spaced set are spaced apart by distances greater than the thicknesses of the portions of the elements of the other set interleaved between said facing surfaces. The spacing means provided for one or both of the third and fourth sets are resilient.

Abstract: A control coupling in which an enclosure houses first and second sets of mutually interleaved elements in a viscous liquid. The first and second sets of elements are arranged for rotation about a common axis and for driving connection with first and second rotatable members respectively. A clutch is provided outside the enclosure and resilient means are arranged to urge the clutch into a disengaged state. A pressure responsive means which is in communication with the enclosure is arranged to engage the clutch against the action of the resilient means when the pressure in the liquid in the enclosure attains a predetermined level.

Abstract: Four wheel drive train including a transfer case adapted to provide full time four wheel drive. A differential is provided in the transfer case and includes both a viscous coupling and a viscous fluid operated mechanical clutch which may be operated to inhibit and prevent differentiation.