CLUTCH ALIGNMENT TOOL

Abstract: A tool (8) for aligning a clutch plate (5) with a pressure plate has an externally threaded tube (10) engaged by a clamping nut (13) and containing a stepped bore (15(16 & 17)). An axially slidable draw bolt (19) passes through the tube (10) and has a draw nut (21) at one end and a tapered head (20) at the other which is located within an enlarged portion (26) of a plastics ferrule (22). The ferrule has axial slots (26) enabling it to be radially expanded by the head (20) being drawn into it when the nut (21) is tightened.

Description: CLDTCH ALIGNMENT TOOL THIS INVENTION relates to mechanical clutches such as are used on motor vehicles, and is more specifically concerned with a tool for aiding re-assembly of a clutch after it has been dismantled. A motor vehicle clutch comprises a flywheel rotated by an engine crank shaft, a clutch plate having a splined hub axial movable on splines provided at one end of a main input gearbox shaft which is coaxial with the drive shaft, and a pressure plate attached to and rotatable with the flywheel. A strong spring is provided in the pressure plate which when the clutch is engaged, holds the clutch plate lining in frictional engagement with the lining on the pressure plate and/or friction surfaces on the flywheel so that the clutch plate transmits drive from the drive shaft to the gearbox. When the clutch is to be disengaged, the spring pressure is reduced to allow the clutch plate lining to separate from the surfaces with which they are in contact. The gearbox input shaft then can rotate independently of the drive shaft and the gearbox is disengaged from the engine. An object of this invention is to provide a tool which keeps the pressure plate and clutch plate coaxial with respect to one another during assembly of a clutch. In accordance with the present invention, a clutch plate centering tool comprises a tube containing an axially slidable, headed draw bolt having a draw nut at one end and a head at its other end which passes through a resiliently deformable enlargement capable of being temporarily radially expanded by having the draw bolt head forced into its interior by tightening the draw nut, an adjustable clamping member being axially displaceable along the outside of the tube. The tube is preferably externally threaded along its length and the member conveniently comprises a circular nut which can be screwed to different positions along the tube. The enlargement conveniently comprises a plastics ferrule having one end fitting neatly into the wide bore end of the tube, and its other end enlarged and longitudinally split so that a tapered head can be drawn into the split end of the ferrule to expand it. Conveniently the tapered head is provided at one end of a draw bolt which extends through the tube and carries a nut at its end which projects from the other end of the tube. By tightening the nut, the tapered head is drawn into the enlargement of the ferrule causing it to expand in the central opening of the clutch plate to grip it tightly. The member can then be partially tightened against the pressure plate so that the clutch plate is held against it. Final adjustments to the position of the clutch plate can then be made. The assembly of the two plates held together by the tool can then be bolted back on the flywheel. This holds the clutch plate in the chosen position allowing the grip of the enlargement on the ferrule to be released and the tool to be removed so that the main input shaft can be fitted. As the clutch-plate has been already centered with respect to the pressure plate, the main input shaft is automatically centered with respect to the drive shaft. The invention will now be described in more detail, by way of examples, with reference to the accompanying drawings, in which:- . IN THE DRAWINGS FIGURE 1 is a diagrammatic cross-section through a clutch plate to be centered within a pressure plate by a tool shown in outline only; FIGURE 2 shows the tool in sectional side elevation; and, ,-v FIGURE 3 shows in simplified outline parts of an alternative construction of tool. 5 Figure 1 shows a clutch plate 5 resting on a table 1 or other flat surface and covered by a pressure plate 2 having a spring diaphragm 4 and an annular surface 3. When the pressure plate 2 forms part of an assembly clutch, its periphery is bolted to a flywheel attached to the engine crankshaft. 10 The clutch plate 5 has a central splined hub 6 through which a main input gearbox shaft passes when the plate 5 is assembled in the clutch. The peripheral portion of the clutch plate 5 is lined with lining 7 which, when the clutch is engaged, are frictionally gripped between the annular surface 3 and a 15 corresponding surface on the flywheel. A tool 8 is used to centre the clutch plate 5 in the pressure plate 2 and will now be described in more detail with reference to figure 2. The tool 8 comprises a cylindrical steel tube 10 having a 20 knurled circular knob 11 at one end. The tube 10 is externally threaded along its length and is screwed through a knurled clamping nut 13 provided with its underface a circular abutment face 14. A steeped bore 15 extends through the tube 10 and has a 25 portion 16 of small diameter and a portion 17 of large diameter. An annular step 28 occurs between the portion 16 and 17. An insert 18 extends through the bore 15 and is provided by a draw bolt 19 having a frusto-conical head 20 at one end. A circular nut 21 at the other end of the insert allows the head 20 to be drawn upwardly towards the adjacent end of the tube 10. The insert includes a nylon ferrule 22 having an enlarged and 5 longitudinally split end 26. The other end of the ferrule is a neat fit inside the' bore portion 17 so that the ferrule and tube are coaxial. The ferrule 22 is internally flared at 25 at its enlarged end in complementary manner to the bolt' head 20 so that the action of drawing the bolt head towards the tube 1010 is to expand the englarged end of the ferrule 22. A washer 30 is located around the bolt 19 between the draw nut 21 and the knob 11. The tool is used as follows:- The clutch plate 5 is placed face down as shown in figure 1, 5 on a flat surface 1. The pressure plate 2 is placed carefully over the plate 5 so that its surface 3 is aligned with the lining 7. The tool 8, which the nuts 14 and 21 at the upper ends of their permitted travel, is fitted through the central opening in the pressure plate 2 as shown in figure 1. The nut 0 21 is tightened to draw the bolt head 20 upwardly into the enlarged end 26 of the ferrule to expand it radially outwards into tight gripping engagement with the splined hub 6. Nut 13 is next .tightened by hand until the lining 7 contact the annular surface 3. The assembly so formed can then be lifted 5 and final adjustment to the centering made after slightly loosening nut 13 if required. Nut 13 is then screwed down tight and the assembly is bolted by the pressure plate 2 to the flywheel of the engine crank shaft. The action of tightening the pressure plate bolts is to loosen 0 the engagement of nut 13 with the spring diaphragm 4. Nut 21 can then be loosened to allow the bolt head 20 to be displaced from the interior of the enlarged end 26 of the ferrule 22 which thereupon reverts to the contracted state illustrated. The tool can then be withdrawn from the assembled clutch and the main input shaft inserted into the hub 6 of the clutch plate 5. As the clutch plate 5 has been centered with respect to the pressure plate 2, and the action of bolting the pressure plate to the flywheel is to centre it correctly with respect to the engine crank shaft, the hub 6 and thus the main input shaft are automatically aligned with one another and even wear on the clutch lining is assured. The embodiment of the invention shown in figure 3 is an early prototype and has parts corresponding in function to like parts of earlier figures, similarly referenced but distinguished by priming. Such parts will not be again described. The distinction between the two embodiments is that the ferrule 22' having the enlarged end 26' is made integrally with the tube 12' and the knob 11', from a high tensile material. In other respects the tool is the same as that already described and is similarly used.

Claims: THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS: 1. A clutch plate centering tool comprising a tube containing an axially slidable, headed draw bolt having a draw nut at one end and a head at its other end which passes through a resiliently deformable enlargement capable of being temporarily radially expanded by having the draw bolt head forced into its interior by tightening the draw nut, an adjustable clamping member being axially displaceable along the outside of the tube. 2. A tool as claimed in claim 1, in which the enlargement is provided at one end of an axially slotted ferrule of plastics material. 3. A tool as claimed in claim 2 r in which the ferrule has one end removably fitted into a bore portion of the tube. 4. A tool as claimed in any one of the preceding claims, in which the tool bore is stepped to provide an annular abutment face engaged by one end of a plastics ferrule which is a close fit inside the bore portion of the tube of larger diameter and has the enlargement formed on its end remote from the tube. 5. A tool as claimed in any one of the preceding claims, in which the clamping member comprises a nut screwed onto the outside of the tube which is externally threaded. 6. A tool as claimed in claim 1, in which the tube and the enlargement are integrally moulded from a resiliently deformable plastics material. 7. A tool as claimed in claim 1, arranged and adapted to be used substantially as described with reference to figures 1 and 2 of the accompanying drawings. 8. A tool as claimed in claim 7, modified substantially as described with reference to figure 3 of the accompanying drawings.

Inventors: HAUBUS WALDEMAR, HAUBUS, WALDEMAR
Applicants: HAUBUS WALDEMAR, HAUBUS, WALDEMAR
Application year: 1985
Main classification: B25B27
IPC codes: B25B27