Fast release mechanism for twin plate friction clutches

A fast release mechanism for a twin plate friction clutch including a biasing member positioned between the intermediate plate and the flywheel surface, and a retaining member for retaining the biasing member in place relative to the intermediate plate or flywheel surface during installation. In one embodiment, the fast release mechanism comprises a spring and a clip that retains the spring in place relative to the intermediate plate. When used with positioner pins extending through the intermediate plate, each clip may be U-shaped and includes a hole on its upper wall and a slot on its lower wall sized to receive the pin. The arms defining the slot extend partly over the end of the springs to keep the spring in place.

FIELD OF THE INVENTION

This invention relates generally to twin plate friction clutches and, more particularly, to fast release mechanisms for twin plate friction clutches.

BACKGROUND OF THE INVENTION

Clutches engage and disengage two moving parts relative to one another. In vehicles, clutches are used to transfer or interrupt the transfer of torque from the engine to the transmission or other drivetrain components. Particularly, they are used to change gears to control the amount of power that is transferred from the vehicle's engine to the transmission to make the vehicle move. This is accomplished through a clutch disc or driving member that can be selectively frictionally engaged with a driving surface of a flywheel that is connected to the engine crankshaft.

Commonly, the clutch cover is bolted to the flywheel, and an axially movable pressure plate is attached to the clutch cover through a mechanism controlled by a release bearing. When the clutch is engaged, the pressure plate is biased against a clutch disc and compressed together with the driving member or flywheel by springs acting against the clutch cover. Disengagement of the clutch by depressing the clutch pedal releases the pressure plate from contact with the flywheel to allow the gears to be changed in the vehicle.

Twin plate clutches utilize an intermediate pressure plate between the pressure plate and the clutch disc or driven member. A first friction disc assembly or clutch disc is positioned between the driving surface of the flywheel on one side and the intermediate plate surface on the other side. A second friction disc assembly or clutch disc is positioned between the other side of the intermediate plate on one side and the pressure plate on the other side. In operation, springs urge the pressure plate towards the flywheel, wherein the first friction disc assembly, the second friction disc assembly and the intermediate plate are compressed together into the flywheel to transfer torque from the flywheel to the transmission.

When the clutch pedal is depressed, it moves a release bearing or member, through springs, straps and/or levers, that pulls the pressure plate away from the flywheel. As the surfaces of the friction disc assemblies wear during use, the length of travel of the components of the clutch assembly thereby increases between the engaged and disengaged positions. As movement of the release member tended to urge the intermediate plate towards its original position, positioner pins have been utilized to adjust the relative position of the intermediate plate during continued operation of the clutch. One example of such positioner pins is disclosed in U.S. Pat. No. 4,941,557, the entirety of which is hereby incorporated by reference.

In the current design of twin plate clutches, there is a time delay between when the pressure plate is moved away or retracted and when the front disc assembly friction surface is completely disengaged from the flywheel and intermediate surfaces. This can negatively affect the ability to utilize the clutch in connection with computer controlled automatic transmissions. Thus, it would be advantageous to provide a mechanism that improves the speed of completely separating the front disc assembly friction surfaces from the flywheel and the intermediate plate surfaces when the clutch is disengaged.

BRIEF SUMMARY OF THE INVENTION

The present invention comprises a fast release mechanism for a twin plate friction clutch. A plurality of springs or other biasing members are positioned in between the intermediate plate and the flywheel surface around the clutch. In one embodiment of a twin plate friction clutch utilizing positioner pins that act to vary the position of the intermediate plate relative to the clutch cover, the springs may be positioned to extend around at least part of the positioner pins. In order to retain the springs in place, especially relative to installation, a clip may be used to secure the spring relative to the intermediate plate or the flywheel.

The clip is generally U-shaped with upper and lower walls connected together by a connecting wall. When used on the intermediate plate having a hole extending therethrough for the positioner pin, the upper wall includes an opening sized to receive the positioner pin and which allows the pin to move therein to adjust the relative position of the intermediate plate during operation. The lower wall may include a slot defined by a pair of arms extending outwardly therefrom to allow the arms to extend around the positioner pin and over part of the spring to secure it in place thereto.

Accordingly, it is an object of the present invention to provide a mechanism for facilitating the disengagement of the clutch.

It is another object of the present invention to provide a mechanism for improving the speed of disengaging the clutch.

It is yet another object of the present invention is to provide a mechanism to improve the disengagement of the clutch that is economical and easy to install.

Other objects, features and advantages of the invention will be apparent from the following detailed disclosure, taken in conjunction with the accompanying sheets of drawings, wherein like reference numerals refer to like parts.

DETAILED DESCRIPTION OF THE INVENTION

While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail several specific embodiments, with the understanding that the present disclosure is to be considered merely an exemplification of the principles of the invention and the application is limited only to the appended claims.

FIGS. 1 through 3illustrate a standard twin plate clutch system100utilizing positioner pins102to adjust the relative position of the intermediate plate104relative to the clutch cover106during continued operation of the clutch. The clutch cover106of the clutch assembly100is shown bolted or otherwise attached to a flywheel108of a vehicle to allow the cover106and flywheel108to rotate together about an axis110defined by a driven shaft112. A spacer ring114or other adapter is positioned between the cover106and flywheel108to provide space for a pressure plate116and intermediate plate104therebetween. Both the intermediate plate104and pressure plate116are rotatably disposed about the shaft112. First and second friction disc assemblies or clutch discs118,120each include friction surfaces or members122,124on opposite sides and a hub126,128that connects each of the friction disc assemblies118,120to the driven shaft112that extends therethrough and is operatively connected to a set of gears in a transmission (not shown).

The first friction disc assembly118is positioned between the surface of the flywheel108and the intermediate plate104. The second friction disc assembly120is positioned between the intermediate plate104and the pressure plate116. The cover106is rotationally connected to the pressure plate116through a first plurality of drive strap assemblies130and to the intermediate plate104through a second plurality of drive strap assemblies132. One example of the structure and operation of the drive strap assemblies is disclosed in U.S. Pat. No. 4,566,573, the entirety of which is hereby incorporated by reference.

A release bearing or release member140is attached by springs142to a plurality of levers144to selectively engage and disengage the clutch. When the release member140is engaged, the levers144pivot anti-clockwise to move the pressure plate116away from engagement with the flywheel108. When the release bearing140is disengaged, the springs142will act to pivot the levers144to move the pressure plate116to compress the first friction disc assembly118, intermediate plate104and second friction disc assembly120together and towards the flywheel108to transfer torque from the flywheel108to the center hubs126,128of the disc assemblies118,120to the transmission.

Repeated engaging and disengaging of the clutch wears down the friction surfaces122,124of the first and second friction disc assemblies118,120, which varies of the position of the clutch components relative to one another and may cause unwanted contact between the intermediate plate104and the friction disc assemblies118,120. Adjustment of the relative position of the intermediate plate104may be done using a plurality of apertures150located around the outer portion158of the intermediate plate104for receiving positioner pins102therethrough. The pins102are sized so that they provide an interference fit with the apertures150so that they may move axially when a force is applied that exceeds the frictional force created by the interference fit.

Referring toFIG. 2, when the clutch assembly100is engaged, the ends152of the positioner pins102contact the flywheel surface108. As the friction members or surfaces122,124of the friction disc assemblies118,120wear away from use, the intermediate plate104will be moved toward the flywheel108along the positioner pins102.FIG. 3shows the clutch assembly100in the disengaged position, wherein the other ends154of the positioner pins102contact the clutch cover106and maintain the intermediate plate104in spaced position between the pressure plate116and flywheel108.

Referring toFIGS. 4 and 5, one embodiment of the fast release mechanism200of the present invention is shown as applied to the intermediate plate104. The fast release mechanism200includes a spring202and a clip204. While a coil spring is shown and disclosed, it is appreciated that the fast release mechanism may utilize a variety of other known biasing members including, but not limited to, strap springs, Belleville washers or leaf springs and not depart from the scope of the present invention. Further, while the fast release mechanism is shown being positioned relative to the intermediate plate, it is appreciated that it may alternatively be positioned or attached to or relative to the flywheel surface.

The clip204is generally U-shaped with upper and lower walls206,208connected together by a connecting wall210. The clip204may be made of steel or other materials having a suitable strength for retaining the end220of the spring202in place. When used on the intermediate plate104having a hole156extending therethrough for the positioner pin102, the upper wall206includes an opening212sized to receive the positioner pin102and which allows it to move therein to adjust the relative position of the intermediate plate104during operation. The lower wall208includes a slot214defined by a pair of arms216extending outwardly therefrom. As shown inFIG. 5, one end220of the spring202is held in place by the arms216of the clip204to retain the spring202in place during installation of the clutch, while the other end222of the spring202remains free. While a clip is shown and disclosed, other retaining members may be used to secure the end of the spring relative to the intermediate plate or flywheel including, but not limited to, screws, rivets or snap rings.

In operation relative to the embodiment shown and disclosed in the drawings, after the springs202are placed over the positioner pins102, the clips204are slid over the outer portions158of the intermediate plate104such that the positioner pins102extend through the holes212on the upper walls206of the clips204and the arms216of the lower walls208of the clips204extend over parts of the ends220of the springs202, thus securing the springs202in place to facilitate attachment of the clutch to the flywheel108.

It will be understood that modifications and variations may be effected without departing from the spirit and scope of the present invention. It will be appreciated that the present disclosure is intended as an exemplification of the invention and is not intended to limit the invention to the specific embodiment illustrated and described. The disclosure is intended to cover, by the appended claims, all such modifications as fall within the scope of the claims.