WEAR INDICATOR ASSEMBLY
Field of the Invention
The present invention relates to a wear indicator assembly. More particularly, the present invention relates to a wear indicator assembly for use in automobile clutches configurable to indicate the extent of wear of clutch discs.
Background of the Invention
Clutches are well known devices that enable transmission of power from the engine to the gearbox of vehicles. A clutch ordinarily comprises of a pressure plate assembly and a clutch disc. The clutch disc is sandwiched between the pressure plate and the flywheel. A release sleeve assembly releases the pressure plate through levers located in the retainer slot. A fork at the end opposite to the driver control assists in pulling the release sleeve assembly. When fully engaged, the whole clutch assembly spins at the same speed as the flywheel and when fully disengaged the pressure plate releases the clutch disc.
The position of release sleeve assembly (setup height of the assembly) is dependant upon the position of the pressure plate. As the clutch disc wears, the release sleeve assembly moves towards the flywheel, which is consequential to the reduction in the set up height of a pull type assembly. When the set up height is reduced beyond a certain limit, the clutch would not release. This requires adjusting the clutch proportionately as the wear takes place.
The set up height of a pull type assembly can be adjusted in several ways. This can be achieved by an adjuster comprising of a pinion meshing with the internal gear of the adjusting ring or by a conventional tool hitting the lugs on the surface of the adjusting ring. The set up height of a pull type assembly is adjusted automatically in the case of self-adjusting type clutches. In the process the adjusting ring slides
according to the inclination of diaphragm. The position of release bearing thus varies according to the wear of friction liner. The wear in friction liners can be measured from the indicating device that projects outside the casing.
United States Patent No. 4, 550, 815 to Gale discloses a clutch having a base fixed to the clutch housing and a microswitch on a carrier. The length of the aperture is such that the clutch lever engages the microswitch when the clutch hnings are worn thereby illuminating the warning light.
A disc clutch with servo mechanism with a cylinder having a signal bore extending from the cylinder working chamber to atmosphere is described in the United States Patent No. 4, 084, 671 to Temehall. A pin seals this bore during the normal operating state. When the clutch is worn, the pin extends into the chamber and the piston comes close to the cylinder bottom and pushes the pin outwards. And subsequently the pin opens an air passage from the chamber to the atmosphere, and an acoustic signal indicates clutch wear.
The arrangement disclosed in the German Patent Numbered DE4414471 to Murase describes a housing being non-rotatably coupled to the clutch counter pressure disc to which an axially movable pressure disc is linked. The clutch disc is fitted between the counter pressure and pressure disc. The pressure is stressed in the direction to the counter pressure disc by a spring. The clutch disc wear causes gap between the pressure disc and the spring and is being detected by an indicator and an adjuster effectively moving the support region of the pressure disc in the direction towards the counter pressure disc such that the gap between the pressure disc and spring is removed.
Summary of the Invention
In one preferred embodiment, herein disclosed is a wear indicator assembly configurable to enable measuring of the extent of wear of clutch discs.
according to the inclination of diaphragm. The position of release bearing thus varies according to the wear of friction liner. The wear in friction liners can be measured from the indicating device that projects outside the casing.
United States Patent No. 4, 550, 815 to Gale discloses a clutch having a base fixed to the clutch housing and a microswitch on a carrier. The length of the aperture is such that the clutch lever engages the microswitch when the clutch linings are worn thereby illuminating the warning light.
A disc clutch with servo mechanism with a cylinder having a signal bore extending from the cylinder working chamber to atmosphere is described in the United States Patent No. 4, 084, 671 to Temehall. A pin seals this bore during the normal operating state. When the clutch is worn, the pin extends into the chamber and the piston comes close to the cylinder bottom and pushes the pin outwards. And subsequently the pin opens an air passage from the chamber to the atmosphere, and an acoustic signal indicates clutch wear.
The arrangement disclosed in the German Patent Numbered DE4414471 to Murase describes a housing being non-rotatably coupled to the clutch counter pressure disc to which an axially movable pressure disc is linked. The clutch disc is fitted between the counter pressure and pressure disc. The pressure is stressed in the direction to the counter pressure disc by a spring. The clutch disc wear causes gap between the pressure disc and the spring and is being detected by an indicator and an adjuster effectively moving the support region of the pressure disc in the direction towards the counter pressure disc such that the gap between the pressure disc and spring is removed.
Summary of the Invention
In one preferred embodiment, herein disclosed is a wear indicator assembly configurable to enable measuring of the extent of wear of clutch discs.
In another preferred embodiment, herein disclosed is a wear indicator assembly that comprises a wear indicator pin having a pressure plate end and a housing end, the pressure plate end having shoulder and the housing end having diameter smaller than the pressure plate end. A bush has been press fitted on a clutch housing. The bush is configured to receive and guide the wear indicator pin. A spring is coupled to the bush on one end and to the pressure plate end of the wear indicator pin on the other end. The wear indicator assembly enables the wear indicator pin to move towards the flywheel relative to the displacement of the pressure plate as the clutch disc wears off. The housing end of the wear indicator pin that is externally visible indicates the extent of wear caused to the clutch disc.
It is an aspect of the present invention to provide for a method of determining the wear of a clutch disc employing a clutch wear indicator assembly.
It is also an aspect of the present invention to provide for a method of determining the wear of a clutch disc. The method comprises of configuring a wear indicator assembly that has a wear indicator pin. The wear indicator pin has a pressure plate end and a housing end, the pressure plate end having shoulder and the housing end having diameter smaller than the pressure plate end. The method further comprises configuring a bush press fitted on a clutch housing. The bush is configured to receive and guide the wear indicator pin. Further the method involves configuring a spring coupled to the bush on one end and to the pressure plate end of the wear indicator pin on the other end. In accordance with the method, the assembly enables the wear indicator pin to move towards the flywheel relative to the displacement of the pressure plate as the clutch disc wears off and the housing end of the wear indicator pin will indicate the extent of wear caused to the clutch disc.
Brief Description of the Drawing Figures
Further objects of the present invention together with additional features contributing thereto and advantages accruing therefrom will be apparent from the following description of preferred embodiments of the present invention which are shown in the accompanying drawing figures with like reference numerals indicating like components throughout, wherein:
Fig. 1 is the sectional side elevation of a clutch assembly showing the wear indicator in position vis-a-vis the pressure plate.
Fig. 2 is the front view of the clutch assembly showing the position of wear indicator relative to the housing
Fig. 3 is an enlarged view of a portion of the view of Fig. 1
Fig. 4 is a sectional view of the front view of the wear indicator
Fig. 5 is the perspective view of the wear indicator.
Detailed Description of the Preferred Embodiment
There is shown a pull type manually adjustable angle spring clutch 100 configured in accordance with the present invention, wherein the friction face 110 of the driven clutch disc 120 touches the pressure plate 130 when the pull type manually adjustable angle spring clutch is engaged. Driven clutch disc 120 has splines on the hub 140, which slides on output shaft 150, which in turn rotates and is used to drive the wheels of a vehicle (not shown). The pressure plate 130 is mounted within a housing 160, which is mounted on the flywheel 170. A plurality of retracting coil springs 175 attaches the periphery of pressure plate 130 to the housing 160.
The housing 160 is supported on the retainer 180 by means of angled coil spring 190, which have an axial component of spring force causing the retainer 180 to move towards the flywheel 170. A plurality of levers 200 having a first end 210, a second end 220 and an offset abutting surface 230 are radially placed around the retainer 180. The first end 210 of each lever fits in a pivot groove 240 in the retainer 180, while the second end 220 has a slot 250 through and an L-shaped mounting pivot 260 projecting from adjusting ring 270 passes through it.
Adjusting ring 270 is fixed, to the housing 160 by a threaded coupling 280 permitting rotation of adjusting ring 270 at the time of wear adjustment.
At the time of disengaging the clutch 100 the retainer 180 is axially pulled away from flywheel 170 against the force of angled coil springs 190. This causes the levers 200 to pivot upon mounting pivots 260 of adjusting ring 270, thereby lifting the abutting surface 230 from pivot surface 290 of pressure plate 130, allowing the clutch 100 to rotate independently of the output shaft 150.
In a pull type manually adjusting angle spring clutch 100 as shown, the position of adjusting ring 270 is changed to compensate for the wear on the clutch disc 120. The amount of wear on driven clutch disc 120 can be gauged accurately using the present invention wherein a wear indicator 300 fitted in the housing 160 consisting of a wear indicator pin 310 inserted and guided in a bush 320 press fitted in the housing 160 under the pressure ot spring 330. The wear indicator pin 310 has a shoulder 340 on the lower portion to prevent it from coming out of the housing. The pressure plate end 350 of wear indicator pin is touching the face 370 of pressure plate 130. After adjustment for wear, the adjusting ring 270 is lowered towards flywheel by rotating it. The housing end 360 of the wear indicator pin 310 has a smaller diameter vis-a-vis the pressure plate end 350 and is visible from outside till the friction material on the clutch disc 120 is completely worn off. The
graduations 380 on the wear indicator pin 310 indicate the amount of wear on the clutch disc at the time of adjustment.
The present wear indicator 300 is assembled in the pull type manually adjustable angle spring clutch 100 by first inserting the wear indicator pin 310 in the housing 160 and then placing the spring 330 followed by press fitting the bush 320 on the housing 160.
After assembling the wear indicator 300 on the assembly with a new clutch disc 120, the end face 360 of wear indicator pin 310 is above the face 400 of bush 320 equal to total wear allowance available on the clutch disc 120. When the clutch disc 120 is fully worn out, the face 360 of wear indicator pin 310 will be flush with the face 400 of the bush 320. Thus the user will know that the clutch disc 120 has been fully worn and needs to be replaced.

We Claim
1. A wear indicator assembly configurable to indicate the wear of a
clutch disc, the assembly comprising
a wear indicator pin having a pressure plate end and a housing end, the
pressure plate end having shoulder and the housing end having diameter
smaller than the pressure plate end;
a bush press fitted on a clutch housing, the bush configured to receive and guide the wear indicator pin;
a spring coupled to the bush on one end and to the pressure plate end of the wear indicator pin on the other end; wherein the assembly enables the wear indicator pin to move towards the flywheel relative to the displacement of a pressure plate as a clutch disc wears off, the housing end of the wear indicator pin thus indicating the extent of wear caused to the clutch disc.
2. The wear indicator assembly according to claim 1, wherein the pressure plate end of the wear indicator pin is touching the face of pressure plate.
3. The wear indicator assembly according to claim 1, wherein the housing end of the indicator pin comprises graduations enabling measuring the extent of wear on the clutch disc.
4. The wear indicator assembly according to claim 1, wherein the shoulder on the pressure plate end of the wear indicator pin prevents the wear indicator pin from coming out of the bush.
5. A method of determining the wear of a clutch disc employing a wear indicator assembly, the method comprising:
configuring a wear indicator pin having a pressure plate end and a housing end, the pressure plate end having shoulder and the housing end having diameter smaller than the pressure plate end;
configuring a bush press fitted on a clutch housing, the bush configured to receive and guide the wear indicator pin;
configuring a spring coupled to the bush on one end and to the pressure plate end of the wear indicator pin on the other end; wherein the assembly enables the wear indicator pin to move towards the flywheel relative to the displacement of a pressure plate as a clutch disc wears off, the housing end of the wear indicator pin thus indicating the extent of wear caused to the clutch disc.