GB2177772A - Clutch release lever arrangement - Google Patents

Abstract

A pull-type clutch 12 in a bell- housing 4 between an engine and a gear box has a release bearing 40 with two diametrically opposed radial lugs 92 each carrying a clip 100. A vertical clutch release lever 52 has opposite vertical side walls 58 each with an horizontal trunnion 62 engaged in one of the clips. Mounted on the bell-housing is a fulcrum arrangement 70 having a shank 74 and a semi-cylindrical bearing head 82 on which the release lever 52 can pivot; the release lever having a vertical slot 68 receiving shank 74. The slot 68 allows the release lever to be lifted a distance X to a position Y where the trunnions are clear of the clips. Then the release lever can be swung in direction C so that the trunnions pass over the lugs after which the release lever can be dropped so that the trunnions come to position Z so that the release lever will not obstruct separation of the engine and bell-housing. In a second embodiment the lever is in the form of a Y-shaped fork with the slot and fulchrum being located intermediately of the ends of the lever below the release bearing. <IMAGE>

Description

SPECIFICATION Clutch This invention concerns a clutch.

The clutch may be in a combination of the type (hereinafter called "the type referred to") comprising a source of rotary motion, rotary motion transmission means, and the clutch, said clutch being engageable to transmit rotary motion to the transmission means from the source and releasable to interrupt the transmitting of the rotary motion to said transmission.

The source of rotary motion may be an engine or motor, for example an engine of a motor vehicle. The rotary motion transmission means may be or comprise gearing and may be, for example a change-speed gear box of a motor vehicle through which gear box one or more road running wheels of the vehicle are driven.

In a known combination of the type referred to for a motor vehicle, the clutch has a driving plate formed by or mounted on a fly-wheel of the engine. The clutch further comprises a cover secured to the driving plate, a pressure plate attached to the cover, a driven plate disposed between the driving and pressure plates, and spring means acting between the cover and pressure plates to clamp the driven plate between the driving and pressure plates.

The clutch is mounted in a bell-shaped housing having its wide end fastened to the engine casing and its other end fastened to the gearbox cover. An input shaft to the gear-box extends therefrom into the bell-housing. This shaft is splined to the driven plate and is surrounded by a release bearing which connects with clutch disengaging levers acting on the spring means. When the clutch is of the pulltype the release bearing is moved towards the gear-box to pull the disengaging levers outwardly of the clutch and thereby relieve the spring pressure and thus release the driven plate from the clamping load.The release bearing is moved towards the gear-box by the pivoting in one sense of a release fork or lever, in the bell-housing, about a pivot on the bell-housing; the release lever being in operative engagement with a flange or other projection means on the release bearing on the side of the projection means facing towards the engine and therefore remote from the gearbox.

Thus when one wishes to separate the bellhousing from the engine, the release fork or lever immediately catches on the release bearing held by the clutch and either prevents the desired separation or unduly restricts it. In German ops2935079 Al the release lever or fork is provided with resilient means biasing the lever or fork into the operative engagement position. The release lever or fork is deformable by a telescoping action (or a pivotal expansion) against the resilient biasing to allow the lever or fork to clear the release bearing and so permit the bell-housing to be moved well away from the engine.

An object of the invention is to provide a combination of the type referred to in which the arrangement of a release lever may be of simple construction allowing ready displacement of the lever from its operative engagement position with a clutch release bearing so that the bearing does not obstruct the lever along an axial direction of the clutch away from the latter and the engine.

According to a first aspect of the invention there is provided a combination of the type referred to further comprising a release lever mounted to pivot relative to fulcrum means disposed in a slot in the lever, release bearing means acting on the clutch to cause release of the clutch when the release bearing means is moved in a first direction by a pivoting movement in a first sense of the release lever in operative engagement with the release bearing means, and the arrangement being such that the release lever is movable out of said operative engagement by moving the lever so as to translate the slot relative to the fulcrum means along a longitudinal direction of at least a portion of the slot.

The release lever in operative engagement with the release bearing can urge flange means on the release bearing when the release lever is pivoted in said first sense.

Hook means may be provided on one of said release bearing means and said release lever to engage with projection means on the other of said release bearing means and release lever when the release lever is in said operative engagement, and the arangement being such that the hook means and the projection means become disengaged by the movement of the release lever which translates the slot as aforesaid.

The release bearing means may have the hook means clipped thereto.

The hook means may comprise at least one resilient hook.

The slot may have an enlarged portion which can fit over a head on the fulcrum means to allow the release lever to be placed on and removed from the fulcrum means.

The combination may be arranged so that the release lever after being moved out of said operative engagement can be moved to a position where the release bearing can hold the release lever away from the position of operative engagement.

According to a second aspect of the invention there is provided a combination according to the first aspect in which the release lever is arranged with a point to be acted upon by an applied force to cause the lever to pivot in the first sense, and the fulcrum means is disposed intermediate said point and the position where the release lever is in operative engagement with the release bearing means.

According to a third aspect of the invention there is provided a combination according to the first aspect in which the release lever is arranged with a point to be acted upon by an applied force to cause the lever to pivot in the first sense so as to move said point in a direction towards the clutch.

The invention will now be further described, by way of example, with reference to the accompanying drawings in which: Fig 1 is a diagrammatic elevation of an embodiment of a combination formed according to the invention; Fig 2 is a partial section on an enlarged scale (relative to Fig 1) of the clutch in the clutch housing of Fig 1 in which the release lever is shown in section on line Il-Il in Fig 3, a clutch release bearing being shown in silhouette for simplicity and a clutch driven plate being shown in plantom lines also for simplicity; Fig 3 is a fragmentary section on line Ill-Ill in Fig 2 in which inner and outer races of the clutch release bearing are represented diagramatically; Fig 4 is a view on an enlarged scale of the portion circled at A in Fig 2;; Fig 5 is a view of the same portion as in Fig 4 with the portion of the release lever in elevation; Fig 6 is a perspective view on enlarged scale of a clip in Fig 2; Fig 7 is a fragment of a front elevation of another embodiment of a release lever for use in the clutch in Fig 2; Fig 8 is a view similar to Fig 2 but shows a modified release lever and modified fulcrum means, the release lever being shown in section on line VIlI-VIlI in Fig 9; Fig 9 is a fragmentary section on enlarged scale on line IX-IX in Fig 8; Fig.10 is a view simillar to Fig.8 showing a modified release bearing in conjunction with the release lever of Fig.8, the release lever being shown in section on line X-X in Fig.11;; Fig. 11 is a fragmentary section on enlarged scale on line Xl-Xl in Fig.10.

Figs.12 and 13 are respectively diagrammatic plan and fragmentary side elevations of the release lever and a modification of the release bearing in Figs. 10 and 11, and Figs.14 and 15 are respectively diagrammatic plan and fragmentary side elevations of a modification of the release lever and of a modification of the release bearing in Figs. 10 and 11.

In the drawings like reference numerals refer to like parts.

With reference to Fig 1 a source of rotary motion 2 exemplified as an engine known per se for a motor vehicle is connected in any suitable manner known per se to a bellshaped housing 4 of a clutch (not shown).

The bell-housing 4 is connected in any suitable manner known per se to a transmission 6 comprising a known change-speed gear box 8 having an output shaft 10 from which drive to one or more road wheels of the vehicle is taken in any suitable manner known per se.

Referring to Figs 2 to 6 the clutch in the bell-housing 4 is shown at 12 and comprises an annular driving plate 14 which may be a fly-wheel driven by a crank-shaft (not shown) of the engine, a driven plate 16 known per se having friction facing material 18 and a central hub 20, and a clutch cover assembly 22 known per se. The cover assembly 22 comprises a dish-shaped cover 24 secured to the driving plate 14, an annular pressure plate 26 connected to rotate with the cover but capable of axial movement relative thereto, and a diaphragm spring 28 known per se.

This spring has a circumferential Belleville portion 30 acting between a fulcrum ring 32 on the cover 24 and annular fulcrum 34 on the pressure plate to clamp the friction material 18 between the pressure plate and the driving plate 14. In known manner the diaphragm spring 28 is formed with dis-engaging levers constituted by known radially inwardly extending fingers 36 spaced by radial slots (not shown). The radial inner ends of the fingers are engaged by a ring 38 held around a release bearing 40 by a circlip 42.

The release bearing 40 comprises an outer race 44 and an inner race 46 (Fig 3) surrounding a guide tube 48. The guide tube fits in an opening in an end wall 50 of the bell-housing 4 and contains an input shaft (not shown) to the gear-box 8. This input shaft meshes in known manner with splines (not shown) lining the central bore of hub 20.

Clutch 12 is a pull-type so that when the diaphragm spring's fingers 36 are pulled in axial direction B by movement in that direction by the release bearing 40 the clamping pressure exerted by the diaphragm spring 28 is relieved and the clutch is released.

A substantially vertical release lever is shown at 52. It is of channel section having a mainly planar base 54 with longitudinally extending side walls 56 and 58; the base being formed with a curved lip 60 at its upper end.

Intermediate its ends the lever 52 has two facing, spaced, co-axial stub-shafts or trunnions 62 and 64 respectively mounted on the facing inner surfaces of the walls 56 and 58; in Figs 2 and 4 the trunnion 62 of the absent wall 56 is shown in dotted line. Between the trunnions the base 54 has an enlongated opening 66 accommodating the guide tube 48. Adjacent its upper end the release lever 52 has a through slot 68 extending some distance along the longitudinal axis of the release lever and formed partially in the lip 60 and partially in the planar portion of the base 54.

Inside the bell-housing 4 the release lever 52 can pivot relative to a fulcrum arrangement 70 comprising a bolt 72 having a wider diameter shank part 74 screwed into the end wall 50 and a narrower diameter shank end part 76 on which a nut 78 and locking device 80 are threaded to retain a plastics bearing 82 bored to receive the bolt shank. The bearing 82 is of semi-cylindrical form with its rounded surface proximate the release lever 52 for the upper end of the latter to roll over that rounded surface during (with respect to Fig 2) clockwise and anti-clockwise pivoting of the release lever relative to the fulcrum arrangement 70. Horizontally the bearing 82 has a length dimension greater than the width dimension of the slot 68.

The lower end of the release lever 52 projects through an opening 84 in skirt 86 of the bell-housing and has an aperture 88 for connection with a clutch actuating arrangement (not shown) worked by the clutch pedal in the vehicle.

The release bearing 40 has two substantially diametrically opposed horizontal lugs 92 and 94 each directed radially outwardly and each adjacent to a respective trunnion 62 or 64 with which the lug co-operates in use. The release bearing 40 includes a plastics sleeve to locate it upon the guide tube 48. This plastics sleeve has at one end a circumferential flange 90 forming two, radial, plastics lugs 95 each overlying a respective radial lug 96 on the release bearing 40 such that each lug 92, 94 comprises a said lug 95 and a said lug 96.

Each lug 92, 94 is gripped by a respective resilient clip arrangement 100 or 102 which can be of metal. The clip arrangement 102 is substantially a mirror image of the clip arrangement 100 and each is mounted on the corresponding lug 92 or 94 in a substantially simillar manner. How each clip is formed and mounted can be more clearly appreciated from Figs 4 and 6 showing the clip arrangement 100. The clip arrangement has two U-shaped clips 104 and 106 at substantially a rightangle to one another so that clip 104 is vertical and clip 106 horizontal with an arm 108 common to both clips. The other arm 110 of clip 104 has an upper free end formed, with respect to the U, with an inturned crook part 112 forming with the arm 108 a narrow entrance neck, in the vertical direction, to the U 104.

The clip arrangement 100 (102) can be push fitted on the corresponding lug 92 (94) which is firmly gripped between clip arms 108 and 116. Cross-piece 114 of the U106 can abut the radially outer free end of the lug 92 (94). To resist dislodgement of the clip arrangement 100 (102), in a vertical direction, the lugs 92 and 94 have obstructions 98 formed by sides of a radial recess or channel 118 (Fig 4) receiving the clip arm 116.

At the clip arrangements 100 and 102, the clips 104 act as retaining hooks in which the respective trunnions 62 and 64 are in operative engagement with the release bearing 40 which is moved in the direction B to release the clutch when the actuating arrangement pivots the release lever 52 anti-clockwise (Fig 2) as indicated by arrow C. During that pivoting movement of the release lever 52 the trunnions 62 and 64 push the lugs 92 via the clip arms 108. As shown (Figs 2 and 4) the arm 110 of each clip 104 can resiliently press the corresponding trunnion 62 or 64 against the corresponding clip arm 108.

In the normal operating position of the release lever 52 in Figs 2 to 5, the crook parts 112 of the clip arrangements 100 and 102 act to resist the trunnions 62 and 64 inadvertently jumping out of the corresponding clips 104.

To move the clutch release lever 52 from its operative engagement with the release bearing 40, the release lever is pushed upwardly from its lower end by a distance X as allowed by the opening 66 and slot 68 which is translated upwardly relatively to the fulcrum arrangement 70. In moving the distance X to position Y the trunnions 62 and 64 push the corresponding clip arms 110 aside which thereafter spring back resiliently. When the trunnions reach position Y neither the flange 90 nor the lugs 92, 94 can prevent the release lever being moved generally along the axial direction B relatively to the release bearing 40. Therefore the release lever 52 can be swung anti-clockwise (Fig 2) to pass over the lugs 92 and 94, so that when the lever descends the trunnions come to position Z at the other side of the lugs 92, 94.Therefore, without needing to keep the release lever 52 raised, the bell-housing 4 and engine 2 may be separated without the release bearing 40 or the release lever 52 obstructing one another.

The curved character of each crook part 112 provides a lead-in enabling the corresponding trunnions 62 or 64 to be located in the corresponding clip 104 when the trunnions are positioned over the clips and the release lever 52 is pulled down enabling the trunnions to push the resilient walls 110 aside as the trunnions pass the crook parts 112.

In Fig 7 the release lever 52 has a key-hole shaped slot 68' with a widened lower end 130. The slot 68' receives fulcrum arrangement 70' which may be similar to the fulcrum arrangement 70 (Fig 2 and 3) except that bearing 82' is substantially hemi-spherical.

When the release lever 52 is lifted so that the widened slot end 130 is alongside the head formed by the bearing 82' and the nut 78, the release lever can be slipped off and onto the fulcrum arrangement 70' by moving the slot portion 130 over the aforesaid head.

In the modification in Figs. 8 and 9 the substantially vertical release lever is in the form of a Y-shaped fork 200 of channel section having a planar base 202 which divides at its upper end into bifurcations 204 separated by a gap 206 accommodating with good clearance the guide tube 48. The base 202 has longitudinally extending side walls 208 and 210 respectively mounting the trunnions 62 and 64 at the upper ends of the side walls.

The lugs 92 and 94 of the release bearing 40 have the respective clip arangements 100 and 102 thereon which provide the retaining hooks 104 in which the trunnions are engaged.

A yoke 212 bolted to the end wall 50 of the bell-housing 4 has two arms 214 and 216 carrying a fulcrum arrangement 218 formed by a substantially horizontal axle comprising a bolt 220 surrounded by a rotatable sleeve 222. This fulcrum arrangement is lower than the release bearing 40 and extends substantially horizontaliy at substantially 90" to the axis D of the release bearing.

The fulcrum 218 extends through coincident slots 224 and 226 in the walls 208 and 210 respectively, the slots extending generally along the longitundinal direction of the release lever 200.

An aperture 228 at the lower end of the release lever 200 is for connection with a clutch actuating arrangement. When that arrangement applies a force in direction E to the lower end of the release lever 200 to move its lower end towards the pull-type clutch 12, the release bearing 40 is moved in the direction B by the pivoting release lever to release the clutch.

By lifting the release lever 200 the distance X to translate the slots 224 and 226 upwards relatively to the fulcrum arrangement 218, trunnions 62, 64 are lifted from the clip arrangements 100 and 102 to the position Y.

Then by swinging the release lever clockwise in Fig.8, the trunnions pass over the lugs 92 and 94 so that the release lever can be dropped to bring the trunnions to the position Z.

If desired, the trunnions 62 and 64 in Figs.2 to 9 can be mounted on the release bearing 40 in place of the lugs 92 and 94. Instead lugs can be provided on the release lever 52 and 20 to which lugs the clip arrangements 100,102 are attached. But in this case each clip 104 is upside down to its previously described attitude so as to enable the clip arrangements to be lifted off the trunnions when the release lever is lifted.

In the modification in Figs.10 and 11 a clutch release bearing 40A is used, this bearing has an outer race 44 having a pair of annular axially spaced flanges 230 and 232 secured thereto and defining an annular groove 234 in which the trunnions 62 and 64 fit to engage the release bearing and move the latter when the forked release lever 200 is pivoted. To restrict relative rotation of the outer race 44 a stop 236 in the form of a pin bridges the groove 234 so that rotation of the race 44 in one sense or the other ceases when the stop contacts either trunnion 62 or 64.

To disengage the release lever 200 from the bearing 40A the release lever is lifted vertically the distance X to bring the trunnions 62, 64 to position Y where they can clear the circumference of the flange 230 when the lifted release lever is pivoted in the direction E about the fulcrum 218. Then the release lever 200 can be lowered bringing the trunnions to position Z. A reverse procedure can re-engage the trunnions in the groove 234.

In the modifications in Fig.12 and 13 a further modified release bearing 40B is used in which flange 232 in Figs.10 and 11 is replaced by an annular flange 232B of greater diameter than the flange 230. Thus the flange 232B prevents the trunnions 62 and 64 passing over the flange when they are in position Y Figs.10 and 11 so that they cannot become located between the release bearing and the diaphragm spring. Also the flange 232B is of a dished shape flaring outwardly and away from the groove 234 towards the diaphragm spring. This flaring of the flange 232B provides a lead-in for the trunnions 62 and 64 when they are being introduced into the groove 234.

Figs.14 and 15 show a further modification of the arrangement in Figs.10 and 11. In this case trunnions 62C and 64C on the release lever 200 are cranked somewhat upwardly and towards the clutch, and on release bearing 40C flange 232C is substantially planar and of greater diameter than the flange 230 so that the flange 232C will prevent the trunnions becoming located between the release bearing and the diaphragm spring.

The release bearing 40A, 40B or 40C can be used in place of the bearing 40 in the arrangement in Figs.1 to 7 in which case trunnions of the type shown at 62C and 64C may be used on the release lever 52.

Claims (26)

1. A combination comprising a source of rotary motion a rotary motion transmission means, and a clutch which is engageable to transmit rotary motion to the transmission means from the source and releasable to interrupt the transmitting of the rotary motion to said transmission means, a release lever mounted to pivot relative to fulcrum means disposed in a slot in the lever, release bearing means acting on the clutch to cause release of the clutch when the release bearing means is moved in a first direction by a pivoting movement in a first sense of the release lever in operative engagement with the release bearing means, and the arrangement being such that the release lever is movable out of said operative engagement by moving the lever so as to translate the slot relatively to the fulcrum means, and said translation being along a longitudinal direction of at least a por tion of the slot.

2. A combination as claimed in Claim 1, in which hook means provided on one of said release bearing means and said release lever engages projection means on the other of said release bearing means and release lever when the release lever is in said operative engagement, and the arrangement being such that the hook means and projection means become disengaged by the movement of the release lever which translates the slot as aforesaid.

3. A combination as claimed in Claim 2, in which the release bearing means has the hook means clipped thereto.

4. A combination as claimed in Claim 2, in which the release lever has the hook means clipped thereto.

5. A combination as claimed in Claim 2, in which the hook means comprises at least one resilient hook.

6. A combination as claimed in Claim 5, in which the projection means comprises at least one stub shaft or trunnion on the release lever, and the resilient hook clips to said trun non.

7. A combination as claimed in Claim 5, in which the projection means comprises at least one stub shaft or trunnion on the release bearing means and the resilient hook means clips to said trunnion.

8. A combination as claimed in Claim 5 and Claim 6, in which the resilient hook has a clip gnpping the release bearing means.

9. A combination as claimed in Claim 5 and Claim 7, in which the resilient hook has a clip gripping the release lever.

10. A combination as claimed in Claim 1, in which the release lever in operative engagement with the release bearing urges flange means on the release bearing when the release lever is pivoted in said first sense.

11. A combination as claimed in Claim 10, in which the flange means defines a side part of a groove in which a projection on the release lever is located when the release lever is located when the release lever is in operative engagement with the release bearing.

12. A combination as claimed in Claim 11, in which the groove extends about the release bearing.

13. A combination as claimed in Claim 11 or Claim 12, in which the projection is a stubshaft or trunnion.

14. A combination as claimed in Claim 13, in which the stub-shaft or trunnion is cranked.

15. A combination as claimed in any one of Claims 11 to 14, in which the groove is disposed between first and second flanges spaced apart axially of the release bearing, the second flange is nearer to the clutch than the first flange, and radially of the release bearing the second flange extends radially outwardly to a greater extent than the first flange.

16. A combination as claimed in any one preceding claim in which the release lever is arranged for lifting to translate the slot as aforesaid.

17. A combination as claimed in any one preceding claim in which the release lever after being moved out of said operative engagement can be moved to a position where the release bearing means can hold the release lever away from the position of operative engagement.

18. A combination as claimed in any one preceding claim, in which the release lever is arranged with a point to be acted upon by an applied force to cause the lever to pivot in the first sense, and the fulcrum means is diposed intermediate said point and the position where the release lever is in operative engagement with the release bearing means.

19. A combination as claimed in any one of Claims 1 to 17, in which the release lever is arranged with a point to be acted upon by an applied force to cause the lever to pivot in the first sense so as to move said point in a direction towards the clutch.

20. A combination as claimed in any one of Claims 1 to 17, in which the fulcrum means is disposed at a higher vertical position than the release bearing means.

21. A combination as claimed in any one of Claims 1 to 17, in which the fulcrum means is disposed at a lower vertical position than the release bearing means.

22. A combination as claimed in any one preceding claim, in which the slot has an enlarged portion which can fit over a head on the fulcrum means to allow the release lever to be placed on and removed from the fulcrum means.

23. A combination as claimed in any one of Claims 1 to 21, in which the fulcrum means comprises axle means extending transversely to the axis of the release bearing means.

24. A combination as claimed in any one preceding claim, in which the release lever is a fork, and with the fork in operative engagement with the release bearing means said bearing means is disposed between the bifurcation of the fork.

25. A combination comprising a source of rotary motion, rotary motion transmission means, and a clutch which is engageable to transmit rotary motion to the transmission means from the source and releasable to interrupt the transmitting of the rotary motion to said transmission, said combination being substantially as hereinbefore described with reference to Figs.1 to 6, Figs.1 to 7, or Figs.8 and 9, or Figs.10 and 11, or Figs. 12 and 13, or Figs. 14 and 15 of the accompanying drawings.

26. A motor vehicle provided with a combination as claimed in any one preceding claim.