GB2152449A - Snow treads - Google Patents

Abstract

A cross-ply tyre casing (e.g. an old casing for low cost) is slotted transversely of its tread surface at uniform intervals around its periphery to leave uniformly spaced portions which provide grip-improving bands D when the casing is fitted over the pneumatic tyre F of a vehicle wheel G. Annular inner portions of the casing may be cut away to ease fitting. The modified casing is fitted over the tyre F when partially deflated. <IMAGE>

Description

SPECIFICATION Snow treads This invention is concerned with improvements in or relating to the provision of snow treads on pneumatic tyres of vehicle wheels.

Many and various different proposals have been made for snow treads, for improving wheel grip in conditions of snow and ice. A very commonly used form, usually referred to as snow chains, is to secure a web of chains around the tyre, the operative chain lengths of the web extending generally transversely of the tyre tread surface (i.e. generally axially of the wheel). Other proposals have involved the use of studs, webbing and straps in many different arrangements and using many different materials.

The known snow treads which give the best performance, being easy to use, (i.e. apply and remove) and giving a good driving performance without undue noise and/or serious damage to either the tyres or road surfaces, tend to be expensive and are apt to damage bodywork.

It is an object of the present invention to provide an improved low-cost method of providing a pneu matic tyre of a vehicle wheel with a snow tread.

The invention provides in one of its aspects a method of providing a pneumatic tyre of a vehicle wheel with a snow tread in which a modified tyre casing of a suitable size is fitted over said wheel tyre, there being cut-outs in said modified casing at intervals around its periphery to leave grip-im proving bands of said casing extending transversely of the tread surface at spaced-apart positions around the periphery of said wheel tyre.

The modified tyre casing may be formed from the carcass of an old cross-ply tyre, at very little cost, simply by cutting away the tread portion of the casing at intervals (preferably uniformly spaced) around its periphery. Radial tyres are probably unsuitable because they are too supple and soft and usually include steel wires which are difficult to cut. It will probably be found necessary, or preferable, to cut away also radially inner portion of the tyre to increase the inside diameter of the tyre, to ease fitting.

In another of its aspects the invention provides a vehicle wheel provided with a snow tread by a method as set out in the last preceding paragraph but one.

In yet another one of its aspects the invention provides a modified tyre casing suitable for use in a method as set out in the last preceding paragraph but two, there being cut-outs in said casing at intervals around its periphery to leave spacedapart grip-improving bands which will extend transversely of the tread surface of a wheel tyre when fitted thereto in accordance with said method.

There now follows a description to be read with reference to the acompanying drawings of a snow tread providing method which illustrates the inventiuon by way of example.

In the accompanying drawings: Figure 1 shows a tyre casing prior to modification; Figure 2 illustrates the form of the tyre casing after modification; and Figure 3 shows a vehicle wheel provided with a snow tread making use of the modified tyre casing.

An old cross-ply tyre casing (Figure 1) is procured and annular inner portions cut away to a radial depth A to increase the inside diameter of the casing.

The casing is next slotted transversely of its tread surface (Figure 2) by cutting away lengths B of the tread portion of the casing to a radial depth C. The portions are cut away at intervals uniformly spaced around the periphery of the casing, leaving uniformly spaced bands D of the casing joined at their ends to remaining annular side walls E of the casing.

To provide a pneumatic tyre F of a vehicle wheel G (Figure 3) with a snow tread, the tyre F is at least partially deflated and the modified old tyre casing, which is of a suitable larger size than the tyre F, is fitted over the tyre F. The tyre F is then reinflated, the modified casing being so retained by the inflated tyre F.

When so fitted, the grip-improving bands D of the modified casing extend transversely of the tread surface H of the tyre F at spaced-apart positions around the tyre periphery, the tread surface being exposed through the cut-outs between the bands D.

1. A method of providing a pneumatic tyre of a vehicle wheel with a snow tread in which a modified tyre casing of a suitable size is fitted over said wheel tyre, there being cut-outs in said modified casing at intervals around its periphery to leave grip-improving bands of said casing extending transversely of the tread surface at spaced-apart positions around the periphery of said wheel tyre.

2. A method according to claim 1 in which the modified tyre casing is formed from a cross-ply tyre casing.

3. A method according to either of claims 1 and 2 in which the tread portion of the casing is cut away at uniformly spaced intervals around its periphery to leave uniformly spaced grip-improving bands.

4. A method according to any one of claims 1, 2 and 3 in which radially inner portion of the tyre casing are cut away to increase the inside diameter of the casing.

5. A vehicle wheel provided with a snow tread by a method according to any one of claims 1 to 4.

6. A modified tyre casing suitable for use in a method according to any one of claims 1 to 4 there being cut-outs in said casing at intervals around its periphery to leave spaced-apart grip-improving bands which extend transversely of the tread surface of the casing.

7. A method of providing a pneumatic tyre of a vehicle wheel with a snow tread substantially as hereinbefore described with reference to the ac

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (9)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Snow treads This invention is concerned with improvements in or relating to the provision of snow treads on pneumatic tyres of vehicle wheels. Many and various different proposals have been made for snow treads, for improving wheel grip in conditions of snow and ice. A very commonly used form, usually referred to as snow chains, is to secure a web of chains around the tyre, the operative chain lengths of the web extending generally transversely of the tyre tread surface (i.e. generally axially of the wheel). Other proposals have involved the use of studs, webbing and straps in many different arrangements and using many different materials. The known snow treads which give the best performance, being easy to use, (i.e. apply and remove) and giving a good driving performance without undue noise and/or serious damage to either the tyres or road surfaces, tend to be expensive and are apt to damage bodywork. It is an object of the present invention to provide an improved low-cost method of providing a pneu matic tyre of a vehicle wheel with a snow tread. The invention provides in one of its aspects a method of providing a pneumatic tyre of a vehicle wheel with a snow tread in which a modified tyre casing of a suitable size is fitted over said wheel tyre, there being cut-outs in said modified casing at intervals around its periphery to leave grip-im proving bands of said casing extending transversely of the tread surface at spaced-apart positions around the periphery of said wheel tyre. The modified tyre casing may be formed from the carcass of an old cross-ply tyre, at very little cost, simply by cutting away the tread portion of the casing at intervals (preferably uniformly spaced) around its periphery. Radial tyres are probably unsuitable because they are too supple and soft and usually include steel wires which are difficult to cut. It will probably be found necessary, or preferable, to cut away also radially inner portion of the tyre to increase the inside diameter of the tyre, to ease fitting. In another of its aspects the invention provides a vehicle wheel provided with a snow tread by a method as set out in the last preceding paragraph but one. In yet another one of its aspects the invention provides a modified tyre casing suitable for use in a method as set out in the last preceding paragraph but two, there being cut-outs in said casing at intervals around its periphery to leave spacedapart grip-improving bands which will extend transversely of the tread surface of a wheel tyre when fitted thereto in accordance with said method. There now follows a description to be read with reference to the acompanying drawings of a snow tread providing method which illustrates the inventiuon by way of example. In the accompanying drawings: Figure 1 shows a tyre casing prior to modification; Figure 2 illustrates the form of the tyre casing after modification; and Figure 3 shows a vehicle wheel provided with a snow tread making use of the modified tyre casing. An old cross-ply tyre casing (Figure 1) is procured and annular inner portions cut away to a radial depth A to increase the inside diameter of the casing. The casing is next slotted transversely of its tread surface (Figure 2) by cutting away lengths B of the tread portion of the casing to a radial depth C. The portions are cut away at intervals uniformly spaced around the periphery of the casing, leaving uniformly spaced bands D of the casing joined at their ends to remaining annular side walls E of the casing. To provide a pneumatic tyre F of a vehicle wheel G (Figure 3) with a snow tread, the tyre F is at least partially deflated and the modified old tyre casing, which is of a suitable larger size than the tyre F, is fitted over the tyre F. The tyre F is then reinflated, the modified casing being so retained by the inflated tyre F. When so fitted, the grip-improving bands D of the modified casing extend transversely of the tread surface H of the tyre F at spaced-apart positions around the tyre periphery, the tread surface being exposed through the cut-outs between the bands D. CLAIMS

1. A method of providing a pneumatic tyre of a vehicle wheel with a snow tread in which a modified tyre casing of a suitable size is fitted over said wheel tyre, there being cut-outs in said modified casing at intervals around its periphery to leave grip-improving bands of said casing extending transversely of the tread surface at spaced-apart positions around the periphery of said wheel tyre.

2. A method according to claim 1 in which the modified tyre casing is formed from a cross-ply tyre casing.

3. A method according to either of claims 1 and 2 in which the tread portion of the casing is cut away at uniformly spaced intervals around its periphery to leave uniformly spaced grip-improving bands.

4. A method according to any one of claims 1, 2 and 3 in which radially inner portion of the tyre casing are cut away to increase the inside diameter of the casing.

5. A vehicle wheel provided with a snow tread by a method according to any one of claims 1 to 4.

6. A modified tyre casing suitable for use in a method according to any one of claims 1 to 4 there being cut-outs in said casing at intervals around its periphery to leave spaced-apart grip-improving bands which extend transversely of the tread surface of the casing.

7. A method of providing a pneumatic tyre of a vehicle wheel with a snow tread substantially as hereinbefore described with reference to the ac companying drawings.

8. A vehicle wheel provided with a snow tread which wheel and snow tread assembly is substantially as hereinbefore described with reference to the accompanying drawings.

9. A modified tyre casing substantially as hereinbefore described with reference to the accompanying drawings.