Pivot ring for a manual clutch

1. A pivot ring for a clutch, comprising:

a first annular segment, a second annular segment and a radial segment,

the first annular segment having a first face on a front side of the ring and the second annular segment having a second face, predominately opposing the first face, on a back side of the ring, the radial segment disposed between the first annular segment and the second annular segment, connecting the first annular segment and the second annular segment,

the pivot ring being insertable between a pressure plate and a diaphragm spring of the clutch such that the first face contacts the diaphragm spring and the second face contacts the pressure plate, the pivot ring being configured so that tapering of the pressure plate when the pressure plate is overheated is allowed to occur without changing a diameter at which the first face contacts the diaphragm spring,

wherein at least one of the first and second annular segments has protrusions.

2. The pivot ring of claim 1 , wherein at least one of the first and second annular segments has an unbroken outer periphery.

3. The pivot ring of claim 1 , wherein the first and second annular segments are of different lengths and the second annular segment is shorter than the first annular segment.

4. The pivot ring of claim 1 , wherein the first annular segment is radially offset outwardly from the second annular segment.

5. A pivot ring for a clutch, comprising:

a first annular segment, a second annular segment and a radial segment,

and the second annular segment having a first face on a front side of the ring and the second annular segment having a second face, predominately opposing the first face, on a back side of the ring, the radial segment disposed between the first annular segment and the second annular segment, connecting the first annular segment and the second annular segment,

the pivot ring being insertable between a pressure plate and a diaphragm spring of the clutch such that the first face contacts the diaphragm spring and the second face contacts the pressure plate, the pivot ring being configured so that tapering of the pressure plate when the pressure plate is overheated is allowed to occur without changing a diameter at which the first face contacts the diaphragm spring,

wherein the first and second annular segments have axially extending pivot portions.

6. The pivot ring of claim 5 , wherein the portions are arcuately shaped, triangularly shaped, hyperbolically shaped, or oval shaped.

7. A clutch assembly, comprising:

a pressure plate having a recess;

a diaphragm spring; and

a pivot ring disposed between the pressure plate and the diaphragm spring,

the pivot ring having a first annular segment, a second annular segment and a radial segment, the first annular segment having a first face on a front side of the ring, which contacts the diaphragm spring and the second annular segment having a second face on a back side of the ring, predominately opposing the first face, which contacts the pressure plate, the radial segment disposed between the first annular segment and the second annular segment, connecting the first annular segment and the second annular segment,

the pivot ring being configured so that tapering of the pressure plate when the pressure plate is overheated is allowed to occur without changing a diameter at which the second face contacts the diaphragm spring,

wherein at least one of the first and second annular segments has protrusions.

8. The pivot ring of claim 7 , wherein at least one of the first and the second annular segments has an unbroken outer periphery.

9. The clutch assembly of claim 7 , wherein the first and second annular segments are of different lengths and the second annular segment is shorter than the first annular segment.

10. The clutch assembly of claim 7 , wherein the first annular segment is radially offset outwardly from the second annular segment.

11. The clutch of claim 7 , wherein the pressure plate has a radial friction surface which is engageable with a clutch disk and transmits torque to a transmission of a vehicle and axially opposing the radial friction surface, the pressure plate has at least a first surface which is spaced apart from at least a second surface by the recess, the radial friction surface and the first surface and the second surface tapering when overheated and the pivot ring being contactable with the pressure plate proximately at the recess.

12. The clutch assembly of claim 7 , wherein the pivot ring transmits an axial force from the diaphragm spring onto the pressure plate.

13. A clutch assembly, comprising:

a pressure plate having a recess;

a diaphragm spring; and

a pivot ring disposed between the pressure plate and the diaphragm spring,

the pivot ring having a annular segment, a second annular segment and a radial segment, the first annular segment having a first face on a front side of the ring, which contacts the diaphragm spring and the second annular segment having a second face on a back side of the ring, predominately opposing the first face, which contacts the pressure plate, the radial segment disposed between the first annular segment and the second annular segment, connecting the first annular segment and the second annular segment,

wherein the first and second annular segments have axially extending pivot portions.

14. The clutch assembly of claim 13 , wherein the portions are arcuately shaped, triangularly shaped, hyperbolically shaped, or have an oval shape.

15. A clutch assembly, comprising:

a pressure plate having a recess;

a diaphragm spring; and

a pivot ring disposed between the pressure plate and the diaphragm spring,

the pivot ring having a first annular segment, a second annular segment and a radial segment, the first annular segment having a first face on a front side of the ring, which contacts the diaphragm spring and the second annular segment having a second face on a back side of the ring, predominately opposing the first face, which contacts the pressure plate, the radial segment disposed between the first annular segment and the second annular segment, connecting the first annular segment and the second annular segment,

wherein the pressure plate has a radial friction surface which is engageable with a clutch disk and transmits torque to a transmission of a vehicle and axially opposing the radial friction surface, the pressure plate has at least a first surface which is spaced apart from at least a second surface by the recess, the radial friction surface and the first surface and the second surface tapering when overheated and the pivot ring being contactable with the pressure plate proximately at the recess, and

wherein the recess, which is located between the first surface and the second surface of the pressure plate, has a first wall extending from the first surface, a second wall extending radially inward from the first side wall, toward an axis of rotation of the clutch assembly, a groove formed at an axially innermost edge of the second wall, and a third wall extending away from the groove, toward the second surface.

16. The clutch assembly of claim 15 , wherein at least the radial segment is disposed within the recess and the second annular segment is disposed within the groove of the recess.

17. A clutch assembly, comprising:

a pressure plate having a recess;

a diaphragm spring; and

a pivot ring disposed between the pressure plate and the diaphragm spring,

the pivot ring having a first annular segment, a second annular segment and a radial segment, the first annular segment having a first face on a front side of the ring, which contacts the diaphragm spring and the second annular segment having a second face on a back side of the ring, predominately opposing the first face, which contacts the pressure plate, the radial segment disposed between the first annular segment and the second annular segment, connecting the first annular segment and the second annular segment,

wherein the clutch assembly further comprises a sensor ring with apertures and axially extending projections of the first annular segment project through the apertures in the sensor ring.