GB2214881A

GB2214881A - Motorcycle rear wheel mounting device

Info

Publication number: GB2214881A
Application number: GB8803695A
Authority: GB
Inventors: Alan Burdett; John Mccarten
Original assignee: JMC ENGINEERING
Current assignee: JMC ENGINEERING
Priority date: 1988-02-17
Filing date: 1988-02-17
Publication date: 1989-09-13
Anticipated expiration: 2008-02-17
Also published as: GB2214881B; GB8803695D0

Abstract

A clamp 38 for a motorcycle rear wheel spindle (32), comprises a fixed portion 38A and a movable portion 38B. The spindle (32) is secured in a mounting block 34 at each end by a socket head screw 52. Each mounting block is held in one of the clamps (38) and clamped in position by means of a screw (46). By means of a projection 40 and recess 42 the two parts of the clamp are relatively pivotable, and can also be separated completely. The wheel spindle is mounted eccentrically on the mounting 34 so that by rotation of the latter by means of a tool inserted in holes 36, the drive chain tension can be adjusted. <IMAGE>

Description

A MOTORCYCLE REAR WHEEL CLAMP This invention relates to clamps for securing the rear wheel of a motorcycle to a swing arm of the motorcycle.

It is desirable that motorcycle rear wheels can be removed from the swingarms easily and rapidly for a number of reasons. For example, in order to repair a puncture, to replace the tyre on the wheel or to replace the complete tyre and wheel assembly. The latter two cases are particulary applicable in the case where the motorcycle is being used in a race or a moto-cross event.

In addition to the requirement of rapid removal and replacement of the rear wheel, it is also necessary to provide some means of moving the wheel spindle relative to the swingarm in order to tension the drive chain of the motorcycle. This requirement is commonly met by mounting the wheel spindle eccentrically in circular blocks in clamps on each side of the swingarm. Rotation of these mounting blocks will tension or slacken the motorcycle drive chain.

A common form of clamp for these mounting blocks comprises a circular housing attached to the swingarm, the circular housing being split along one side and having one or more bolts to draw the edges of the split together in order to clamp the mounting block within the housing. Such an arrangement requires the clamps on both side of the swingarm to be released and for the wheel spindle to be released from the mounting blocks. A further type of clamp comprises once again, a circular housing attached to the swingarm but in this case the circular housing comprises two parts hinged together on a pin, with the clamp having one or more bolts to draw the two parts of the housing together and to clamp the mounting block between the two parts of the housing This arrangement is an improvement upon the arrangement described above.

The present invention seeks to provide a rear wheel mounting for a motorcycle which allows the rear wheel to be removed and replaced rapidly and which allows the rear wheel to be moved relative to the swingarm in order to- correctly tension the drive chain of the motorcycle.

In particular, the present invention seeks to provide a clamp for a motorcycle rear wheel mounting, the clamp being in two parts, one of which is attached to the swingarm, the two parts of the clamp being securable together to secure a mounting for a rear wheel spindle in position.

Accordingly, the present invention provides a clamp for a motorcycle rear wheel spindle mounting, the clamp comprising a fixed portion and a movable portion, the two portions having engagement means to allow relative rotational movement between the two portions to allow removal and replacement of the wheel spindle mounting from and to the clamp, and clamping means to secure the two portions of the clamp together and to clamp the spindle mounting between the two portions of the clamp.

The engagement means can comprise a projection on one of the portions and a corresponding recess on the other portion.

Preferably the projection is part circular with the recess being correspondingly formed.

The portion having the projection of the engagement means can be attached to the swingarm of a motorcycle.

The portions can have abutment faces to limit the relative rotational movement between the two portions.

The portions can be disengaged by relative axial movement.

The clamping means can comprise one or more bolts.

The present invention will know be more particulary described with reference to the accompanying drawings in which, Fig. 1 is an elevation of a typical swingarm for a motorcycle, Fig. 2 is a plan view of the swingarm shown in Fig. 1, Fig. 3 is a side elevation of one form of clamp according to the present invention secured to a motorcycle swingarm, Fig. 5 is an end elevation of a motorcycle rear wheel and spindle, together with spindle mounting blocks and, Fig. 4 is an end view of the clamp shown in Fig. 3.

Referring to the Figs, a swingarm unit 10, shown in Figs. l and 2 for the rear wheel of a motorcycle, includes two beams 12 and 14, braced by a cross member 16. The beams 12 and 14 have a number of lugs 18 for the attachment of various components of the motorcycle. A circular housing 20 is attached to the end of each beam 12 and 14. Each housing is split at 22 and has a clamping means 24 to enable the free edges of the housing to be drawn together. The clamping means 24 comprises the boss 26 on each side of the split 22 on the housing 20, and a bolt 28 passing through both bosses 26 and a nut 30 engaging the bolt 28.

A spindle 32 for the motorcycle rear wheel see (Figs. 3 and 4), is mounted eccentrically in two spindle mounting blocks 34. Each block 34 has holes 36 to receive corresponding projections on an adjusting tool (not shown).

In order to adjust the tension of the driving chain of the motorcycle, the nut and bolt 28 and 30 of the clamping means 24 are released and the adjusting tool is located in the hole 36, and the mounting blocks 34 are rotated in the housing 20 until the correct tension is obtained. The nut and bolt 28 and 30 are tightened on each housing 20 to maintain the blocks 34 in the correct position.

0 It would be appreciated that the removal of the spindle 32, together with the motorcycle rear wheel from the housing 20, is a lengthy process. It will involve the releasing of the nuts and bolts 28 and 30 on each housing and the release of the spindle 32 from each mounting block.

Referring to Figs. 3, 4 and 5 which illustrate one form of clamp according to the present invention, components corresponding to those illustrated Figs. 1 and 2 have been alotted the same references numbers. Each block 34 is secured in a two part clamp 38, each part being an extruded section. The clamp 38 comprises a fixed part 38A, one of which is welded to the end of each beam 12 and 14, and a movable part 388 which is hinged on the fixed part 38A.

The parts 38A and 38B are hinged together by means of a projection 40 on part 38A, which is part circular in section and engages with a recess 42 in part 38B, which is shaped to correspond with the projection 40. The circular portions of both the projection and recess 42 extend over arcs greater than 1100, and part 38B is assembled on part 38A by sliding part 388 axially over part 38A so that projection 40 engages in the recess 42. However, once assembled part 388 can hinge freely the on part 38A.

Clamping means 44 are provided to secure the free end of the part 388 to the part 38A. The clamping means comprise a socket head screw 44, which passes through a hole 48 in the free end of the part 388 and engages in a threaded recess 50 in the part 38A Referring to Fig. 4 the spindle 32 is held in each mounting block 34 by a socket head screw 52, and is prevented from rotating in the block by means of a dowel pin 54 engaging a flat 56 on the end of the spindle 32.

Fig. 5 shows the complete assembly which is to be removed from and replaced on the swingarm 10 of the motorcycle, and comprises the wheel spindle 32 with the mounting blocks 34 at each end, a motorcycle wheel 58 and associated bearings 60, a drive sprocket 62 which engages with the drive chain (not shown), with a spacer 64 being provided between the drive sprocket and the mounting block 34. On the opposite side of the wheel, a disc 66 of a disc brake is mounted for rotation with the wheel 58, together with the stationary calliper 68 of the disc brake.

The assembly shown in Fig.5 and partially shown in Figs. 3 and 4, is assembled in each clamp 38, by releasing each cap screw 46 and rotating the part 38B so that each mounting block 34 can be positioned between the two parts 38A and 388. Once positioned, each part 388 is rotated towards the closed position and the socket screws 46 are used to draw the parts 38A and 38B together until each mounting block is lightly held in position. The adjusting tool is then located in the holes 36 and the mounting blocks rotated until the correct chain tension is obtained. The screws 46 are then fully tightened to clamp each mounting block 34 in the correct position.

When it is required to replace the wheel 58 it is clearly a very simple matter to release both screws 46 and to rotate the hinge portions 388 of each clamp 38 so that the whole assembly as shown in Fig. 4 can be released from the swing arm of the motorcycle.

Once a fresh tyre or wheel has been placed in position the whole can be rapidly replaced, adjusted and clamped in position using the two part clamps 38.

It will be clear that the above arrangement and other arrangements according to the present invention, offer significant advantages in terms of ease, and speed of removal and replacement of motorcycle rear wheels as compared with the once piece clamp illustrated in Figs. 1 and 2

Claims

CLAIMS 1. A two part clamp for a motorcycle rear wheel spindle mounting comprises a fixed portion and a movable portion, with engagement means between the two portions to allow relative rotational movement between the two portions, and clamping means to secure two portions together to clamp a mounting in position.
2. A clamp as claimed in claim 1, in which the engagement means comprise a projection on one of said portions, located in a correspondingly formed recess in the other one of said portions.
3. A clamp as claimed in claim 2, in which the projection and recess are part circular extending over an arc greater than 1800.
4. A clamp as claimed in anyone of the preceding claims, in which the two portions are disengagable one from the other by relative axial movement.
5. A clamp as claimed in anyone of the preceding claims, in which the fixed portion is securable to an end of a swingarm of a motorcycle.
6. A clamp as claimed in anyone of the proceding claims, in which the clamping means comprises at least one bolt passing through a opening in one of the said portions, and engagable with a threaded recess in the other one of said portions
7. A clamp as claimed in claim 6, in which the bolt passes through an opening in the movable one of said portions, and engages in a threaded recess in the fixed one of said portions.
8. A clamp for a motorcycle rear wheel spindle mounting and constructed and arranged for use and operation substantially as herein described, and with reference to Figs. 3, 4 and 5 of the accompanying drawings.
9. A motorcycle swingarm including a clamp as claimed in any one of the preceding claims.

1Q. A motorcycle including a swingarm as claimed in claim 9