GB2364286A

GB2364286A - Flexible track for a tracked vehicle

Info

Publication number: GB2364286A
Application number: GB0116382A
Authority: GB
Inventors: Frederick Powada
Original assignee: Individual
Current assignee: Individual
Priority date: 2000-07-04
Filing date: 2001-07-04
Publication date: 2002-01-23
Anticipated expiration: 2021-07-04
Also published as: GB0016415D0; GB2364286B; GB0116382D0

Abstract

A flexible track for a tracked vehicle, e.g. a small vehicle used in bomb disposal operations, has transverse solid teeth 2, 3 with concavities 4 on one (Fig. 2) or both flanks. The track is in the form of a belt of moulded reinforced rubber material. The top of each tooth can be flat or crowned. The sharp edge 6 between the top of a tooth and a concavity helps grip, particularly on wet surfaces, acting like a squeegee.

Description

2364286 TRACKS This invention relates to tracks f or track-laying vehicles

and particularly to such tracks designed to 5 enable the vehicles to climb stairs, descend stairs, or traverse uneven terrain.

Track laying vehicles where the track is made of hard rubbery composite material have been known f or decades, 10 and track designs are disclosed, f or example, in GB-A256796, GB-A- 948843, and US-A-3857617.

GB-A-2288580 describes flexible belt tracks for tracklaying vehicles consisting of a belt having transverse 15 teeth on it for engaging the surface on which the vehicle is placed. The teeth have ground-engaging tips running transverse to the direction of the track and, in accordance with the invention described in this specification, the flanks of the teeth, i.e. the surfaces

20 on either side of the apex of the tooth, not the side surfaces which are usually flat and in parallel planes defining the sides of the track, are convexly curved at least in part, or have an outer contour which approximates to a convex-curving part. At the root of 25 each tooth there is a concavely curved section where the tooth flank contour merges into the flatt outer surface of the belt. Various tooth designs are disclosed which are particularly intended to assist the vehicle in climbing stairs. 5 Tracks in accordance with the invention described in GBA-2288580 have found application in a variety of areas, most particularly in tracks on self-propelled vehicles used in bomb disposal applications. Such vehicles must, 10 in particular, be able to climb up or down stairs, go up or down curves and negotiate various other obstacles and move effectively across both smooth ground and rough ground, for example ground strewn with stones, rocks or pebbles.

I have now found that contrary to the teaching disclosed in the British specification referred to above, the substantially improved results can be obtained by using tracks in which the ground-engaging transverse teeth are,

20 on at least one flank, concave at a position spaced away from the root of the tooth. I have f ound that track belts provided with such teeth may be manufactured in a variety of embodiments and may be tailored without difficulty to suit the intended application.

Thus according generally to the present invention there is provided a flexible belt track for a tracked vehicle, the track having a series of transverse solid teeth on its ground-engaging face, wherein at least one of the 30 flanks of each tooth comprises a concave portion located remote from the root of the tooth and shaped to provide a re-entrant portion of the tooth flank relative to a plane perpendicular to the direction of extension of a straight portion of the track.

The concavity on one or both sides of the tooth may be a smoothly varying curve or, for example, a series of 3 joined flat surfaces approximating to a concave shape.

Making one or both flanks of the tooth concave at a position remote from the tooth root gives particular 5 advantage in the case of tracks designed for use in wet conditions. The teeth, which generally have a height to width ratio of 0.4 to 2, preferably have a concavity f ormed on one or both flanks which, in at least one case, is terminated by a relatively abrupt edge, the edge 10 preferably having an internal angle of less than 90. This edge is f ound to act in the manner of a squeegee or wiper blade and to act in practice to clean water from any surf ace with which the tooth has to engage. The load application point on a stair is also no longer on the 15 stair nose, but is set back away from the curve when the stair nose is radiused. A vehicle equipped with a belt track with such a tooth shape accordingly better adapted to operation in wet conditions, the extent of slippage of the teeth on wet surfaces being reduced.

Tracks with teeth with concave flanks are not wholly unknown, and are indeed disclosed in EP-A-0776774. However, the teeth there disclosed are of a complex construction with an internal space, and would be wholly 25 unsuitable for use on a stair-climbing load-carrying vehicle.

The flexible tracks according to the present invention are made in known fashion and analogously to those 30 described in GB-A-2288580 referred to above. Generally the materials used to construct the belt will be appropriate for the envisaged use in terms of weight, flexibility, flammability, wear resistance and the like. The standard techniques of assembling the tracks in 35 moulds with reinforcing fibres which become embedded in a rubber or rubbery matrix are well-known and do not need to be described further here.

The accompanying drawings will serve to illustrate the invention further. In these drawings, various individual track geometries are shown, mostly in axial section, and by way of example only of the myriad of alternative 5 designs which may be encompassed within the scope of the present invention.

In the drawings, Figure 1 is a diagrammatic perspective view of section of track in accordance with the invention 10 and Figure 1A a section through the track of Figure 1; Figure 2 shows seven alternative tooth track configurations A to G, schematically and in axial section.

Referring first to Figures 1 and 1A, these show a section of an elongate track consisting of fibre or cord reinforced rubbery material, preferably rubber of appropriate grade. On one side of the belt are provided 20 a series of standard transverse corrugations in the nature of relatively low profile transverse teeth 1 which, when the track is installed appropriately, engage with a drive wheel or drive sprocket located on the vehicle. The other side of the track, uppermost in the 25 drawing, has spaced teeth 2, 3, each of which has on each of its f lanks a concavity 4 remote from and not to be confused with the concave sections where the tooth flanks merge at the bottom of the tooth into the top surf ace (as shown in Figure 1 and 1A) of the belt.

As can be seen in Figure 1, and particularly in the cross-section denoted Figure 1A, the top of each tooth is formed into an edge 5 which acts on wet surfaces rather like a squeegee. Adjacent each edge 6 is the generally 35 concave portion 4 of each f lank of each tooth. We have f ound that track configured as shown in Figures 1 and 1A is highly effective in stair-climbing applications.

Figures 2A to G show a variety of non-symmetrical tooth forms, each of which has one concave flank and one convex flank. Each has a single sharp edge adjacent its top.

5 The tooth profiles shown in Figures 2A to C are highly ef f ective, but the edges tend to get damaged. In the configurations shown in Figures 2D to G, the tooth has a general flattening across its top, which serves to reduce wear on the edge. This can be further reduced by 10 crowning the top of each tooth slightly as shown on the right hand tooth in Figure 2G.

Numerous variations in terms of the shape, depth and contour of the concavity may be made with a view to 15 optimising the tooth shape for any given area of application.

Claims

1 A flexible belt track for a tracked vehicle, the track having a series of transverse solid teeth on its 5 ground-engaging face, wherein at least one of the flanks of each tooth comprises a concave portion located remote f rom the root of the tooth and shaped to provide a reentrant portion of the tooth f lank relative to a plane perpendicular to the direction of extension of a straight portion of the track.

2. A flexible belt track according to Claim 1 wherein the height to width ratio of each tooth is less than 2 and wherein the concave portion terminates at or near the 15 tooth tip in a relatively abrupt edge.

3. A flexible belt track according to Claim 2 wherein the top of each tooth is f lat.

20

4. A flexible belt track according to Claim 2 wherein the top of each tooth is crowned or carries a bead or other protrusion.

5. A flexible belt track according to any one of Claims 25 2 to 4 wherein the internal included angle of the edge in a plane perpendicular to the edge is less than 90.

6. A flexible belt track according to any one of Claims I to 5 and consisting of cloth and/or cord-reinforced rubber, or rubbery polymeric material.

7. A flexible belt track according to Claim 1 and having teeth substantially as illustrated in any of Figures 1 or 2 of the accompanying drawings.

8. A tracked vehicle having a flexible belt track according to any one of the preceding Claims.