Title: Wheel for a tracked vehicle

Description of invention

The invention relates to a wheel specifically adapted for use on tracked vehicles, and in particular although not exclusively to use on military tracked vehicles, where the wheel is substantially T-shaped in cross section from the centre to the rim.

Tracked vehicles include a large number of wheefs, as each track requires a plurality of pairs of wheels, which run inside the track. These are usually referred to as "road wheels" although they run inside the track rather than directly on the road or other ground surface. To retain the track correctly aligned around the wheels, some or all of the track sections include centre guides, and one wheel of each pair runs on each side of the centre guides. The face of each wheel that is adjacent the centre guides often rubs on the centre guides and thus suffers wear.

Some such wheels are substantially T-shaped in cross section from the centre to the rim as this is a shape which provides advantages in particular in terms of weight. However, they do also suffer from some disadvantages relating to the difficulty of manufacture and the strength of the wheel rim.

In order to reduce the wear suffered by such wheels various forms of wear elements have been incorporated into the wheels, For example, the main bodies of such wheels are often cast from aluminium, and it is known to include wear elements of a more wear resistant materia!, such as steel, as inserts when casting the main bodies. Other known methods of providing a wear element are to spray a second metal onto the main body of the wheel around the inner edge of the rim, or to rivet a wear element in place. However, all of these options require the wheel to be returned to a factory for

refurbishment when the wear element needs replacement, which is less than idea! when the vehicle is in active service. Furthermore, none of these options contribute significantly to the strength of the wheel, which it would be advantageous if they did.

It is an object of the present invention to provide a wheel specifically adapted for use on tracked vehicles, which is substantially T-shaped in cross-section from the centre to the rim, which obviates the above described problems and which, when it is suffering from wear, can preferably be refurbished without being returned to the factory.

According to a first aspect of the present invention there is provided a wheel specifically adapted for use on tracked vehicles having a main body whiGh is substantially T-shaped in cross-section from the centre to the rim, the main body including a rim with a circumferentiai surface having an inner edge and an outer edge, the inner edge in use facing centre guides of the track, wherein the wheel includes a wear element secured to the inner edge of the rim by threaded fasteners characterised in that a locking compound is used between the inner edge of the rim and the wear element before the threaded fasteners are inserted and the wear element thus contributes to the structural performance of the wheel.

The inner edge of the rim preferably includes a formation to assist in correctly locating the wear element when securing it to the inner edge of the rim and retaining it in place during use. The formation may be a Hp or a recess.

The wear element may include a formation to co-operate with the formation on the inner edge of the rim.

The wear element may be a single piece which extends around the inner edge of the rim, or it may be a plurality of pieces which combine to extend around the inner edge of the rim.

The wear element may be made from steel, and the main body may be made from aluminium.

According to a second aspect of the present invention there is provided method of making a wheel specifically adapted for use on tracked vehicles comprising the steps of: a) forming a main body which is substantially T-shaped from the centre to the rim, the main body including a rim with a circumferential surface, an inner edge and an outer edge, the inner edge in use facing centre guides of the track; b) forming a wear element; c) applying a locking compound to the inner edge of the rim; d) putting the wear element in place on the inner edge of the rim, and e) securing the wear element to the inner edge of the rim by threaded fasteners.

According to a third aspect of the present invention there is provided a wheel and track assembly specifically adapted for a tracked vehicle comprising a track having a plurality of track sections some or a!l of which include centre guides and a plurality of wheels according to the first aspect of the invention or made according to the second aspect of the invention.

According to a fourth aspect of the invention there is provided a tracked vehicle including a wheel and track assembly according to the third aspect of thρ> invention

An example of a wheel according to the present invention will now be described, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of the inner side of a wheel according to the invention; Figure 2 is a perspective view of the outer side of the wheei of Figure 1 ; Figure 3 is a cross sectional view through the rim of the wheel of Figure 1 ; Figure 4 is a cross sectional view through the rim of a second embodiment of a wheel according to the invention;

Figure 5 is a perspective view of two pairs of wheels and a single wheel on a section of track, and

Figure 6 is an end view from the left hand end of Figure 5.

Referring first to Figures 5 and 6, the general arrangement of road wheels R and a track T is illustrated in perspective and end views respectively. Sections t of the track T include centre guides C. Pairs of road wheels R are secured together as shown such that one runs on each side of the centre guides C, This configuration is used in the prior art, and in the present invention.

Referring now to Figures 1, 2 and 3, a road wheel 10 includes a main body 12 which is substantially T-shaped. The top of the T-shape is a rim 14 with an inner edge 16 and an outer edge 18. The main body 12 also includes a disc 20, which forms the upright part of the T-shape, and which is offset slightly to one side of the rim 14. The disc 20 includes holes 22 by means of which the wheel 10 is secured to a tracked vehicle in use. In use a tyre 24 (not shown in Figures 1 and 2), of solid rubber or like material, is fixed to the rim 14.

Thp innpr p>dπ» 1fi nf thfi rim 14 has secured to it. bv means of a oluralitv of

plurality of holes 30 there through for receipt of the threaded fasteners 26. The inner edge 16 of the rirn14 is formed with a lip 32 around the outer edge such that the wear element 28 fits just inside the lip 32. This assists in locating the wear element 28 accurately in piace during the process of securing it to the rim 14 and furthermore assists in retaining the wear element 28 in place during use of the wheel 10, as it is keyed to the rim 14.

Before the wear element 28 is secured to the rim 14 either or both of the wear element 28 and the inner edge 16 of the rim 14 is coated with a locking compound, as appropriate for the compound used. Then the wear element 28 is put into piace on the inner edge 16 of the rim 14 and secured there by means of the threaded fasteners 26. Doing this means that the wear element 28 is more resistant to displacement from its correct position than would otherwise be the case. It also means that, if the wear element 28 is formed of a strong material, such as hardened steel, the presence of the wear element 28 contributes to the structural performance of the wheel 10.

In use each road wheel R on a tracked vehicle is a wheel 10, and the wheel 10 is oriented such that the wear element 28 is facing the centre guides C of the track. As the vehicle is used the centre guides C will contact the wear elements 28 on the wheels 10 and over time those wear elements 28 will be worn down. When a wear element 28 is worn and needs replacing the wheel 10 may not need to be returned to a factory or the like for refurbishment. Rather, it may be possible for the old wear element 28 to be removed and replaced quite simpiy by maintenance staff using the maintenance facilities routinely available to them. Where this is possible it reduces the disruption and the period of time that the vehicle is out of use.

Rpførrinπ tn Fiπurø 4 Ά narfiai r.rnss section nf a second embodiment of wheel

34 and the wear etement 28 includes a !ip around it's radially outer edge which cooperates with that recess. This embodiment provides for additional location when in use, assisting the threaded fasteners In securing the wear element 28 to the rim 14 which means that the wear element 28 is even less likely to be displaced during use, when the centre guides C of the track T contact the wear element 28, than with the first embodiment and also assists in ensuring that the wear element 28 contributes to the structural performance of the wheel 10,

In alternative embodiments the wear element may be made up of a number of segments, which between them provide a complete or nearly complete ring.

The wear element may be formed of any material having suitable wear resistance and other properties, as applicable to the use to which the wheel and vehicle will be put, and with regard to the material from which the main body 12 of the wheel 10 is made.

The number of threaded fasteners 26 used to secure the wear element 28 to the inner edge 16 of the rim 14, and the type of threaded fastener 26, are selected in order to provide the desired level of clamp ioad between the wear element 28 and the inner edge 16 of the rim 14. If a locking compound is used that will also be selected in order that the combination provides the desired level of clamp load between the wear element 28 and the inner edge 16 of the rim 14.

When used in this specification and claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.