GB2085174A - Tyre and wheel balancing machines - Google Patents

Abstract

A device for mounting tyre and wheel assemblies to a balancing machine comprises a spindle 1 on which the assembly to be tested is positioned, an abutment 2 on the spindle against which the wheel is located, a conical adaptor 3 to centralise the assembly on the spindle 1 and a clamping ring 4 to lock the adaptor 3 and retain the assembly on the spindle. The spindle 1 and adaptor 3 are provided with complementary formations e g one or more flats 14, 15 and 17, 18 to prevent relative rotation therebetween so that in use forces generated during acceleration and deceleration of the device do not cause the adaptor to unlock. <IMAGE>

Description

SPECIFICATION Tyre and wheel balancing machines This invention relates to balancing machines for tyre and wheel assemblies of the off the car type and more particularly to a device for mounting a tyre and wheel assembly to such machines.

The machines comprise a longitudinally extending shaft one end of which projects from the machine body and on this end the tyre and wheel assembly to be tested is mounted. Current practice is to locate the assembly by means of the centre hole in the wheel disc so that the assembly runs concentrically to the shaft but because the centre hole diameter varies from car to car it is necessary to provide for a range of centre hole diameters. This is done by means of a conical adaptor which is engaged in the centre hole and presses the wheel against a flat backing disc known as a universal adaptor plate, the pressure being generated by a nut run tightly up behind the conical adaptor.

Modern machines operate automatically to spin the wheel and stop it when sensing has been completed. The accelerations and decelerations used are substantial to reduce the time of operation and accordingly it is most important to ensure that torque forces generated do not unwind to lock the nut and ailow the wheel assembly to fly off the mounting shaft as is prone to occur with known machines.

It is an object of the present invention to provide a wheel mounting device which providesforthe above requirements with the addition of easier operation than hitherto.

The present invention provides a device for mounting a tyre and wheel assembly to a balancing machine, the device comprising a spindle on which the assembly to be tested is mounted in use, an abutment at one end of the spindle against which one side of the wheel is located in use, a conical adaptor having an axially extending locating hole which is slidably engageable upon said spindle so that in use the conical surface engages a central hole in the wheel to centralise the assembly on the spindle and a clamping ring to urge the conical adaptor towards the abutment to hold the wheel against the abutment wherein the conical adaptor and spindle have complementary formations such that relative rotation therebetween is prevented.

The complementary formations are preferably provided upon the spindle and within the locating hole of the conical adaptor. Conveniently the com plementaryformations comprise a flat provided upon the spindle and a complementary flat within the locating hole of the conical adaptor. More preferably two diametrically opposed flats are provided upon the spindle and two complementary flats within the locating hole of the conical adaptor.

Preferably the or each conical adaptor flat extends from the outer end of the locating hole which is at the wider end or base of the conical adaptor so that the conical adaptor may be rotated whilst initially fitting it onto the spindle to facilitate engagement of the complementary formations but is prevented from rotation when it is subsequently moved along the spindle towards its final position engaging the wheel.

Preferably the or each spindle flat ends before the radial plane containing the abutment and at least part of the remaining portion of the spindle and the inner or leading end of the locating hole of the conical adaptor are of complementary cross-section, preferably circular, to centralise the conical adaptor on the spindle.

The clamping ring is preferably internally screw threaded and the outer end of the spindle, apart from the aforementioned flats, is externally threaded such that the ring may be rotated thereon to lock the conical adaptor against the wheel. The threaded ring may have external flats or lugs to allow tightening but a preferred arrangement is to provide a radially inwardly extending hole or holes in the outer surface of the ring in which a C spanner is received to allow tightening.

The spindle may comprise an integral extension of the shaft of a wheel balancing machine but more preferably the spindle is adapted for releasable attachment to the shaft to allow removal and/or replacement of the device.

Preferably the abutment comprises a universal adaptor consisting of an annular plate or disc member which encircles the shaft and provides an annular abutment face for one side of the wheel of an assembly to be tested. Preferably the plate or disc member has a recessed centre portion so that the abutment face is radially spaced from the outer surface of the spindle for engagement with the wheel disc.

The universal adaptor may be separate from the spindle and axially located therefrom by suitable means but more preferably the universal adaptor is integral with the spindle, although the two may be manufactured separately and welded together.

The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings wherein: Figure lisa cross-section of the mounting device according to the present invention; Figure 2 is an end view of the conical adaptor, and Figure 3 is a side view of the conical adaptor.

The device shown in the accompanying drawings for mounting a tyre and wheel assembly on a balancing machine (not shown) comprises a cylindrical spindle 1, a universal adaptor 2 integral with the spindle at one end thereof, a conical adaptor 3 slidably engageable with the spindle 1 to centralise a tyre and wheel assembly mounted thereon and a clamping ring 4 engageable with the spindle 1 to lock the conical adaptor 3 and retain the tyre and wheel assembly on the spindle.

The spindle 1 has a coaxial tapered mounting bore 5 to allow mounting of the device on the shaft (not shown) of the balancing machine so as to rotate with the shaft. The universal adaptor 2 comprises an annular plate 6 having a recessed centre portion 6a and a peripheral edge portion 6b radially spaced from the outer surface of the spindle 1 which provides a plane face 6c against which the wheel disc7 of the assembly to be tested is held.

The conical adaptor 3 has an axially extending locating bore 8 which is slidably engageable upon the spindle 1 and an outer conical engagement surface 9 which engages a central location hole 10 in the wheel disc 7 to centralise the assembly and to locate the wheel disc 7 against the plane face of the adaptor plate 6 in the conventional manner.

The locating bore 8 has a first portion 11 of circular cross-section which is an accurate sliding fit on a portion 12 of corresponding diameter machined on the spindle 1 and provides accurate radial location of the components. The remaining portion 13 of the locating bore 8 is of non-circular cross-section having two opposed flats 14 and 15 which are parallel and identically spaced from the axis of the conical adaptor 3.

The circular spindle portion 12 ends at a shoulder 16 which is a short distance beyond the radial plane containing the abutment face 6c as shown. The spindle portion 17 to the right of the shoulder 16 as shown in Figure 1 is of a slightly smaller diameter than the portion 11.Two opposed flats 18 and 19 are machined in the smaller diameter portion 17 which are complementary to the conical adaptor flats 14 and 15 and the remaining curved surface of the smaller diameter portion 17 is screw threaded.

The internally threaded clamping ring 4 is engageable with the spindle portion 17 and axially adjustable thereon to engage the wider end of the conical adaptor 3 to urge the latter towards the universal adaptor and locate the wheel discS against the face 6c. Tightening of the clamping ring 4 is achieved by means of a C-spanner engageable with a hole 20 extending radially inwardly from the outer surface of the ring.

In use the spindle 1 and universal adaptor 2 are releasably mounted upon the balancing machine.

The operator lifts a wheel and tyre assembly onto the spindle 1 and fits the conical adaptor 3 over the threaded spindle portion on which it is a loose fit and need not be positioned in any special way. The conical adpator 3 is slid along the spindle until the internal adaptor flats 14 and 15 abut the outer end of the spindle 1. The operator then rotates the adaptor 3 to align the adaptor flats with the complementary spindle flats; this is easily accomplished because the adaptor is small and comparatively light and most importantly the interengaging formations or flats are only at the outer end or base of the adaptor and can therefore be seen by the operator, and the adaptor 3 slid along the spindle 1 to engage the radial locating portions 11 and 12. The clamping ring 4 is then spun down the spindle 1 to abut the conical adaptor 3 and press it towards the universal adaptor 2 to hold and locate the wheel against the face 6c, the tyre and wheel assembly being centralised by the engagement of the outer conical surface 9 of the adaptor 3 in the wheel disc location hole 10. Finally a locking force is applied to the clamping ring 4 by means of a C-spanner.

Removal is equally simple as the components are all comparatively smali and easily handled furthermore very tight locking is not needed as the drive and braking forces are taken by the complementary formations. Finally, the construction of the present invention completely overcomes any tendency for the mounting device to unlock in use which is a fault of several mounting systems at present in use.

Claims (21)

1. A device for mounting a tyre and wheel assembly to a balancing machine, the device comprising a spindle on which the assembly to be tested is mounted in use, an abutment at one end of the spindle against which one side of the wheel is located in use, a conical adaptor having an axially extending locating hole which is slidably engageable upon said spindle so that in use the conical surface engages a central hole in the wheel to centralise the assembly on the spindle and a clamping ring to urge the conical adaptor towards the abutment to hold the wheel against the abutment wherein the control adaptor and spindle have complementary formations such that relative rotation therebetween is prevented.

2. A device according to claim 1 wherein the complementary formations are provided upon the spindle and within the locating hole of the conical adaptor.

3. A device according to claim 1 or claim 2 wherein the complementary formations comprise a flat provided upon the spindle and a complementary flat within the locating hole of the conical adaptor.

4. A device according to claim 3 wherein at least two flats are provided upon the spindle and a corresponding number of complementary flats within the locating hole of the conical adaptor.

5. A device according to claim 4wherein the spindle flats are uniformly spaced in the circumferential direction.

6. A device according to any one of claims 3,4 or 5 wherein the or each conical adaptor flat has an axial length less than the axial length of the locating hole.

7. A device according to claim 6 wherein the or each conical adaptor flat extends from one end of the locating hole.

8. A device according to claim 7 wherein said one end is at the base of the conical adaptor.

9. A device according to claim 7 or claim 8 wherein the other end of the locating hole is of uniform increased transverse cross-section.

10. A device according to claim 9 wherein the or each spindle flat ends before the radial plane containing the abutment and at least part of the remaining portion is of uniform transverse crosssection corresponding to said other end of the locating hole.

11. A device according to claim 9 or claim 10 wherein said other end of the locating hole is of circular cross-section.

12. A device according to any one of the preceding claims wherein the clamping ring is internally screw threaded and at least part of the spindle is externally screw threaded.

13. A device according to claim 12 wherein the clamping ring includes means for tightening the clamping ring to lock the conical adaptor against the wheel.

14. A device according to claim 13 wherein the tightening means comprises at least one hole extending radially inwards from the outer surface of the ring for engagement with a locking tool.

15. A device according to any one of the preceding claims wherein the spindle is adapted for attachment to the shaft of a balancing machine for rotation therewith, the spindle being detachable from the shaft.

16. A device according to any one of claims 1 to 14 wherein the spindle is an integral extension of the shaft of a balancing machine.

17. A device according to any one of the preceding claims wherein the abutment comprises a universal adaptor.

18. A device according to claim 17 wherein the universal adaptor consists of an annular plate which encircles the shaft and provides an abutment face for one side of the wheel.

19. A device according to claim 18 wherein the plate has a recessed centre portion and the abutment face is radially spaced from the outer surface of the spindle.

20. A device according to any one of claims 17, 18 or 19 wherein the universal adaptor is integral with the spindle.

21. A device for mounting a tyre and wheel assembly to a balancing machine substantially as hereinbefore described with reference to the accompanying drawings.