WO1997043137A1

WO1997043137A1 - Tyre tread pattern

Info

Publication number: WO1997043137A1
Application number: PCT/GB1997/001268
Authority: WO
Inventors: Richard O'connell
Original assignee: BANDVULC REMOULDS Ltd
Current assignee: BANDVULC REMOULDS Ltd
Priority date: 1996-05-10
Filing date: 1997-05-09
Publication date: 1997-11-20
Anticipated expiration: 1998-11-10
Also published as: GB9610306D0; AU2709097A

Abstract

A tyre especially for on/off road trucks, four-wheel drive vehicles, dump trucks, wheeled diggers, earth moving machinery and lorries on building sites has a tread comprising circumferential shoulder bars defining a trough therebetween and a series of discrete projections disposed about a substantially central zone of the tread, within said trough.

Description

TYRE TREAD PATTERN

This invention relates to tyres having treads which are particularly adapted for use on on/off road trucks, four- wheel drive vehicles, dump trucks, wheeled diggers, earth moving machinery and the like.

It is well known that the tread patterns of tyres can improve the grip or traction of a moving vehicle, and generally comprise a series of grooves or slits opening to at least the road contacting surface of the tyre. Such tyre tread patterns are generally intended to duct water, lying on a wet surface, away from the road/tyre interface, thereby improving the adhesion of the tyre to the surface in wet or otherwise slippery conditions. However, the tyres of on/off road trucks, four-wheel drive vehicles, dump trucks, wheeled diggers, earth moving machinery, lorries on building sites and the like tend to become clogged with mud, clay or building materials which are not readily dispersed from conventional tread and thus accumulate in the tread of the tyre, impeding the grip or traction of the tyre and, once the vehicle is travelling on a road, depositing debris on the road. Conventionally, this problem has been addressed by simply providing wider, deeper grooves in the tyres but on soft ground such grooves still become clogged.

It is therefore an object of the present invention to provide tyres having a tread pattern which is less prone to becoming clogged when used on soft ground or in snow.

Accordingly, the invention provides a tyre particularly for on/off road vehicles, four-wheel drive vehicles, dump trucks, wheeled diggers, earth moving machinery, and the like, the tyre having a tread comprising circumferential shoulder bars defining a trough therebetween, discrete projections being disposed about a substantially central zone of the tread within said trough. Preferably, the projections are in the form of oval or circular blocks or studs but may have other shapes such as square or diamond. Where oval blocks are used, the major axis of the blocks is preferably laterally-disposed between the shoulder bars. The blocks may constitute a single, centrally-disposed series between the shoulder bars or may be arranged as two or more series where the blocks may be alternating or in lateral alignment. The profile between the internal edges of the shoulder bars and the base of trough is preferably curved; the walls of the projections preferably also merge with the base of the trough via a curved section.

The shoulder bars may optionally be provided with sipes, which open to the ground-contacting surface of the shoulder bars. The sipes, which are generally laterally- disposed, are preferably straight but may be curved or formed as a "V" or "W" pattern. The sipes may be alternately-disposed in the respective shoulder bars but preferably correspond, that is, are laterally aligned and also correspond with the projections.

The shoulders provide support to and promote even wear of the tyre tread. Advantageously, the shoulders generate low noise levels in use. Traction for the tyre is provided by the series of projections.

Conveniently, the recessed area or trough formed between the shoulder bars and around the projections allows any debris which adheres to the tyre to be shed easily, thus tending to prevent the accumulation of debris and consequential clogging of the tyre tread. Overall, the tyre tread provides good traction in soft ground or snow and good self-cleaning properties when driving from a site onto a road.

Embodiments of the invention will now be described in detail, by way of example, with reference to the accompanying drawings, of which:

Figure 1 is a perspective view of a tyre having a tread according to the invention;

Figure 2 is a plan view of a repeating unit of the tyre tread of Figure 1, and

Figure 3 is a cross-section taken along line III-III of Figure 2.

Referring firstly to Figure 1, a tyre is shown generally at 10 and has a sidewall 11. The tread consists of shoulder bars 12, 13 disposed peripherally at the outer edge regions and defining a trough and a well 14 therebetween. The shoulder bars are divided by siping 15, 16 extending to the floor or base of the well 14 to form shoulder blocks 17, 18 of rectangular shape. The well 14 accommodates circular blocks 19 disposed as a single central series and having their lateral diameter in alignment with the siping, as more clearly shown in Figure 2. Figure 3 shows the profile between the shoulder bars, the base of the trough and the blocks.

Claims

1. A tyre having a tread comprising circumferential shoulder bars defining a trough therebetween and a series of discrete projections disposed about a substantially central zone of the tread, within said trough.

2. A tyre according to Claim 1, in which the projections are in the form of circular or oval blocks.

3. A tyre according to Claim 1 or Claim 2, in which the projections constitute a single centrally-disposed series between the shoulder bars .

4. A type according to claim 1 or claim 2, in which the projections constitute two or more laterally-disposed series, the projections being alternating or laterally aligned.

5. A type according to any preceding claim, in which the shoulder bars are provided with stripes which open to the ground-contacting surface of the shoulder bars .

6. A tyre according to claim 5, in which the sipes are correspondingly-disposed in the respective shoulder bars.

7. A type according to claim 6, in which the sipes are positioned in correspondence with at least some of the projections .

8. A type according to any of claims 5 to 7 , in which the sipes are straight.

9. A tyre according to any of claims 5 to 8, in which the sipes divide the shoulder base as a series of rectangular blocks