The present invention relates to improvements in relation to wheel spacers for vehicles and more particularly to adjustable wheel spacers.

After sale modifications to vehicles are now very common place - both for aesthetic purposes (such as adding bodywork, spoilers, tinting windows etc) and for mechanical purposes (raising or lowering suspension, engine modifications etc). One such modification which is very popular and well known is to install wheel spacers which change the track of a vehicle (the distance between the wheels across the width of the vehicle). This is done both for aesthetic reasons as well as to change the handling of the vehicle.

The wheel of a vehicle is mounted on a hub which is carried on the vehicle suspension. In some vehicles, the hub has mounting bolts carried on it which extend through mounting holes in the wheel, with the wheel being fixed in place by nuts which screw onto the projecting ends of the bolts. More commonly now, however, the hub is provided with threaded holes which align with holes in the wheel so that mounting bolts can be inserted through the holes in the wheel and screwed into the threaded holes in the hub to secure the wheel in place. In either configuration, the wheel spacer is inserted between the hub and the wheel and has holes in it which align with the holes in the wheel so that the bolts (whether carried on the hub or inserted through the wheel) pass through the wheel and the spacer and the spacer is clamped in place between the hub and the wheel when the wheel nuts or bolts are tightened. The presence of the spacer means that the wheel, when tightened up, is located further from the hub and hence the track of the wheel is increased.

An alternative spacer design has mounting studs carried on the spacer for engaging through the holes in the wheel, as well as mounting holes in the spacer by means of which it is secured to the hub, so that the spacer is secured on the hub and the wheel then secured on the spacer. One of the reasons why fitting of wheel spacers is so popular is because it does not need any specialist equipment - the fitter simply needs to be able to remove the wheel, equipment for which is present in most cars to enable fitting of a spare wheel in the event of a flat tyre. However, one of the problems associated with the process for either of the designs set out above is choosing the right size spacer for the particular vehicle. If too wide a spacer is used, then the wheel bolts can be over stressed resulting in failure and the wheel coming off. It can, therefore, be a case of trial and error, necessitating the installer to buy a number of different sizes to get the correct one. This also makes it more difficult for suppliers and manufacturers as they need to make a number of different sizes to accommodate different requirements, and practical limitations often mean that the range of sizes is limited to the most common ones, limiting customer choice.

Adjustable wheel spacers are known in the art in which multiple plates of different thicknesses are supplied to allow variation in the overall thickness, but this still has the problem of the manufacturer having to produce a range of sizes to suit all requirements, and also increases the risk that the end user could chose to put too many plates in than is safe, resulting in failure of the mounts.

According to the present invention there is provided an adjustable wheel spacer comprising a first spacer part having an end face on one end and a recess extending axially from an opposing end towards said end face, a second spacer part having an end face, said second spacer part being telescopically engageable in the recess of the first spacer part, and camming means associated with said first and second spacer parts, said camming means engaging when said second spacer part is engaged in the recess of the first spacer part such that relative rotation between said first and second spacer parts about a longitudinal axis of the spacer causes axial movement of said second spacer part into or out of said recess, and wherein each of said first and spacer parts includes a plurality of axial through-openings which extend through the end face and which form mounting holes equi-angularly arranged on a common radius around said longitudinal axis such that at least some of said through-openings in each spacer part are alignable with each other in a plurality of different relative rotational positions of said spacer parts so as to allow, in use, wheel mounting means to engage through both parts of the spacer and thereby lock said parts relative to each other.

An adjustable wheel spacer according to the invention has the advantage that it enables a wide range of spacer adjustment in a secure a reliable manner whilst requiring only two parts, thereby making it simpler for production as well as for installation.

The camming means may comprise a spiral ram formation on one of the spacer members and a mating follower on the other of the spacer members which moves along the ramp formation as the two members are rotated relative to each other, causing the members to move away from each other (rotation in one direction) or allowing them to move back towards each other (rotation in the other direction).

In the preferred embodiment, however, the camming means comprises a threaded coupling between the two members, in particular a female thread formed on the inner surface of the recess in the first spacing member and a corresponding male thread formed on the outer surface of the second member such that the second member can be screwed into and out of the recess in the first member. This has the advantage that the screw configuration is more secure, holding the two parts together against telescopic movement in either direction and also allows a wider range of adjustment as it is not limited to one 360 degree relative rotational movement.

Each of the first and second spacer parts is preferably cylindrical, said first part being formed as a hollow cylinder with a radially inwardly extending surface formed on one end which forms said end face. The end face of the first spacer part is preferably an annular end face having a central opening therein. The second spacer part has the male thread formed on its outer cylindrical surface which is sized to complement the female thread formed on the inside of the first spacer part so as to be screwingly engageable therein. The second spacer part may be a solid cylinder with said said through openings passing therethrough, or may be formed as a hollow cylinder with one end closed, similar to said first spacer member, the male thread then being formed on the outer surface extending from an end which is remote from said closed end such that the second spacer part engages in the first spacer part open end first.

Preferably, the number of through opening in each spacer part is a multiple of 5, in particular 10 through openings. Modern vehicles typically have 5 wheel nuts or bolts and hence the provision of through openings which form the mounting holes in multiples of 5 enable a wider range of adjustment. 5 holes would have 72 degree symmetry so that the holes align every 72 degrees of relative rotation, whereas 10 holes gives 36 degree symmetry, enabling a greater degree of adjustment whilst ensuring that the holes are not so close together to compromise the structural integrity of the spacer. The through openings lie on a common radius equal to the radius of the mounting holes on the wheel with which it is intended to be used.

The spacer may include means to restrict the maximum adjustment thickness of the spacer so as to ensure that there is sufficient overlap between the first and second spacer parts to safely carrying the loading applied between the two parts. Such means may be a safety mark on the outer surface of the second spacer part which becomes visible when the two parts have exceeded their maximum outward adjustment.

The through openings in the spacer may receive the wheel mounting bolts such that the wheel is still secured directly to the hub with the mounting bolts passing through the spacer and screwing into the mounting holes in the hub. In an alternative embodiment, however, one of said first and second parts includes wheel mounting studs extending outwardly from an end face by means of which a wheel is mountable directly onto said part and hence on said spacer. In this embodiment, then, the through holes are used to receive mounting bolts by means of which the spacer is secured to the hub, and a wheel is located on the wheel mounting studs and secured thereon by wheel nuts screwing onto said studs, thereby securing the wheel to the spacer rather than the hub. Preferably, each stud is positioned midway between a pair of through holes so as to maximum the strength of the spacer. In order that the invention may be well understood, there will now be described an embodiment thereof, given by way of example, reference being made to the accompanying drawings, in which:

Figure 1a is a front view of a first spacer part of an adjustable wheel spacer according to a first embodiment of the invention;

Figure 1 b is a perspective view of the first spacer part of Figure 1 a;

Figure 2 is a perspective view of a second spacer part of the adjustable wheel space of the invention;

Figure 3 is a perspective view of the first spacer part of Figure 1a and second spacer part engaged together;

Figure 4 is a sectional view of the spacer part of Figure 3 assembled on a wheel hub; and

Figure 5 is a perspective view of a first spacer part according to a second embodiment of the invention.

Referring first to Figures 1a and 1 b, there is shown a first spacer part 2 of an adjustable wheel spacer 1 according the present invention. The first spacer part 2 is formed as a hollow cylinder which is open at one end 3 and has an annular end face 4 at the other end with a central opening 5 formed therein which is sized to allow the protrusion on a typical wheel hub to engage therein so that the first spacer part can be fitted on a wheel hub with its annular end face 4 engaged flush against the wheel hub mounting surface as shown in Figure 4. The annular end face 4 of the first spacer part 2 also has 10 through openings 5 formed in it each located with its centre on a common radius r about the centre of the first spacer part 2 which is equal to the common radius of the wheel bolt mounting holes on the wheel hub with which it is intended to be used. The 10 holes are also equi-angularly distributed around the end face 4 so that their centres are located every 36 degrees. In this way, the first spacer part 2 can be positioned on the wheel hub with one of the through openings 5 aligned with each of the wheel hub mounting holes. The illustrated embodiment is based on use with a typical wheel hub which has 5 mounting holes so that every other through opening in the end face 4 aligns with a wheel hub mounting hole, the extra through openings 5 enabling a greater adjustment resolution of 36 degrees to bring the holes into the next alignment position rather than the 72 degrees which would be necessary if just 5 holes were included. The invention could equally be applied to a wheel hub which works with just 4 wheel studs, in which case the end face would have a multiple of 4 through openings equi-angularly spaced around it, in particular 8 openings at 45 degree intervals.

As can be seen in Figure 1 b, the inner circumferential surface 6 of the first spacer part 2 has a female thread 6a formed thereon extending from the open end of the spacer part 2 so as to enable a second spacer part 10 shown in Figure 2 to be screwingly engaged therein.

Referring now to Figure 2, there is shown a second spacer part 10 which screwingly engages with the first spacer part 2 to form the adjustable spacer 1 of the invention. Like the first spacer part 2, the second spacer part 10 has ten through openings 11 formed therein on the same common radius r as the through openings 5 in the first spacer part 2 so that the openings in the two spacer parts 2, 10 can be axially aligned with each other. The second cylindrical part 10 also has a central opening

12 corresponding with the central opening 3 in the first spacer part 2.

As shown in Figure 2, the second spacer part 10 has an outer cylindrical surface

13 on which is formed a male thread 13a which complements the female thread 6a formed on the inner surface 6 of the first spacer part 2 such that the second spacer part 10 is screwingly engageable in the first spacer part 2 to formed the adjustable spacer 1. As the two spacer parts 2, 10 are rotated relative to each other, the second spacer part 10 either retracts into or extends out of the first spacer part 2 depending on the direction of relative rotation, varying the spacing between the remote end faces 4, 14 of the two spacer parts 2, 10 and hence the thickness of the spacer 1. The second spacer part 10 includes markings 9 on its outer cylindrical surface 13 which are covered by the first spacer part 2 when the two parts are properly engaged but which becomes visible when the second part 2 has been unscrewed too far out of the first part 1 to clearly indicate to the installer that the limit of adjustment has been reached.

Due to the equi-angular distribution of the through openings 5, 11 in the two spacer parts 2, 10, the through openings 5, 11 in the two parts will be axially aligned every 36 degrees of relative rotation, in which position wheel mounting bolts of stubs can be engaged through aligned holes, locking the two parts against relative rotation and hence locking the thickness of the spacer 1 .

In use, therefore, the spacer is adjusted to the required size by winding the second spacer part 10 into or out of the first spacer part, the two parts being positioned relative to each other so that the through openings 5, 11 are in axial alignment. The spacer 1 is then located on the wheel hub 15 with the aligned through openings 5, 11 aligned with the wheel mounting holes 16 in the hub 15 as shown in Figure 4. The wheel 17 is then presented against the outer face of the space with the mounting holes 17a in the wheel aligned with the through openings in the spacer 1 , allowing the mounting bolts 18 to be engaged through the wheel 17 and spacer 1 and screwed into the mounting holes 16 in the hub, thereby securing the wheel 17 and spacer 1 to the hub 15. To facilitate the locating of the wheel on the spacer 1 , the second spacer part 10 may include an annular ring which extends around the central opening 12 and projects axially away from the first spacer part 2, the annular ring being sized to be a close fit with the central opening in the wheel so that wheel engages on the annular ring to during assembly.

Figure 5 shows an alternative embodiment of the first spacer part 101 which includes wheel mounting studs 108 extending axially outwardly from its end face 104, the studs 108 being arranged concentrically and equi-angularly spaced on the same circumference as the through openings 105 but off-set to the through openings so that each stud is centrally located between the adjacent through openings to maximise strength. Otherwise, the first part 101 of the embodiment of Figure 5 is identical to that of Figure 1a, and the second part screwingly engages therewith in exactly the same way. In difference to the first embodiment, the spacer 101 of this embodiment is mounting directly to the hub with the first part remote from the hub and secured in place by mounting screws which are inserted through the through-openings 105, 11 in the spacer and screw into the hub, thereby securing the spacer 101 directly to the hub. The wheel is then secured to the spacer 101 rather than to the hub by engaging the wheel on the wheel mounting studs 108 of the first part 102 which extend away from the hub and then fastening it in place by means of wheel nuts which screw onto the mounting studs. In this way, the spacer is secured to the hub and the wheel is secured to the spacer. It will, of course, be understood that the studs may instead be provided on the end face of the second spacer part, in which case the spacer will be mounted on the hub with the second part outermost.

It will be recognised that the adjustment resolution is determined by the pitch of the thread which is formed on the two spacer parts and hence the axial movement which results from winding in and winding out of the two parts. A coarse thread will give a bigger total range of size adjustment for the spacer but a smaller number of selectable sizes, whereas a finer thread will give a smaller total adjustment range but a larger number of selectable sizes.