GB2071027A - Tyres - Google Patents

Abstract

An inflatable tyre, (2) particularly for a wheelbarrow, has a closed cross- section defined by a semi-circular part (6) terminating in two concave parts (3,4) which are connected by a convex part to form an inwardly bulging lobe (5). The tyre has an inflation valve (8), and may be made of plastics, eg. PVC. <IMAGE>

Description

SPECIFICATION Tyres The present invention relates to tyres and particularly, but not exclusively, to tyres for wheelbarrows.

Existing techniques of manufacturing wheelbarrows provide for the barrows to be equipped tyres of traditional or conventional type, i.e. tyres having a rubber carcass with reinforcing cloth and steel wires and requiring an airtube.

Careful market research has shown that in wheelbarrows in general use it is the rubber tyre which is subjected to the lowest amount of wear. In fact, when all the other components of the wheelbarrow are worn out, i.e. worn to such an extent that it is impossible to use them any longer, the tyre is generally still in a good state.

Considering therefore the fact that conventional rubbertyres are used in wheelbarrows at a low speed of revolution and at a low load, and that their expensive characteristics are not fully exploited, one can envisage that a type of tyre that would be particularly suitable for wheelbarrows, but far cheaper than the conventional type of tyre, would be desirable.

According to the present invention there is provided a tyre comprising a hollowtoroidal inflatable elementwherein the intersection of the tyre with any plane including the tyre axis defines a closed line having a semi-circular part and another curved symmetrical part comprising two flexures which define a bulging lobe, an inflation valve being provided in the hollowtoroidal element.

The invention will be now further described, by way of illustrative and non-limiting example, with reference to the accompanying drawing, in which: Figure 1 is the side view of a tubeless tyre embodying the invention; and Figure 2 is the plan view, partially in section, of the tyre Figure 1.

Atyre 1 shown in the drawing comprises a tubular toroidal chamber or element 2 (Figure 2) of closed section having on its outer side a semi-circular section and, on its inner side, a symmetrical curved section wherein two opposing flexures 3 and 4form a central bulging lobe 5.

A series of grooves 6, lying in planes perpendicular to the axis 7 of the wheel, are made along the semi-circular outer side to afford a tread pattern.

An inflation or air valve 8 of a known type is housed on the inner part, preferably (as shown) in correspondence with the lobe 5.

Different materials may be employed in the making of the chamber or element 2 of the tyre, though many tests has shown that a plastics material (preferably polyvinyl chloride (PVC)) is most suitable in that its life is substantially the same as that of the traditional tyres made of rubber and cloth, it easily endures the generally minimal stress to which it is subjected, and its production cost is lower than that of the conventional tyres.

The tyre 1 is mounted directly on a wheel rim and thereafter inflated. Due to the inflation pressure, the chamber 2, which was previously floppy, takes on the shape indicated in Figure 2 and the bulging lobe 5 fits into the inner walls of the rim, exerting against them a pressure sufficient to clamp the tyre in place and prevent it from moving with respect to the rim.

The tyre 1 can thus offer the advantages of quick and easy mounting, and of costing a lot less than traditional tyres due to the absence of an inner air tube, to the use of plastics material much cheaper than rubber, and to the use of a chamber without reinforcement cloth and/or steel wires, whereby the manufacturing process is much easier, quicker and cheaper.

1. A tyre comprising a hollow toroidal inflatable element wherein the intersection of the tyre with any plane including the tyre axis defines a closed line having a semi-circular part and another curved symmetrical part comprising two flexures which define a bulging lobe, an inflation valve being provided in the hollowtoroidal element.

2. Atyre according to claim 1, wherein the toroidal element is of plastics material.

3. A tyre according to claim 2, wherein the plastics material is polyvinyl chloride.

4. A tyre according to any one of the preceding claims, having on an outer part thereof a series of grooves or the like which afford a particular tread pattern.

A tyre substantially as herein described with reference to the accompanying drawing.

6. Awheel including a tyre according to any one of the preceding claims.

7. A wheelbarrow incorporating a wheel according to claim 6.

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

Claims (7)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Tyres The present invention relates to tyres and particularly, but not exclusively, to tyres for wheelbarrows. Existing techniques of manufacturing wheelbarrows provide for the barrows to be equipped tyres of traditional or conventional type, i.e. tyres having a rubber carcass with reinforcing cloth and steel wires and requiring an airtube. Careful market research has shown that in wheelbarrows in general use it is the rubber tyre which is subjected to the lowest amount of wear. In fact, when all the other components of the wheelbarrow are worn out, i.e. worn to such an extent that it is impossible to use them any longer, the tyre is generally still in a good state. Considering therefore the fact that conventional rubbertyres are used in wheelbarrows at a low speed of revolution and at a low load, and that their expensive characteristics are not fully exploited, one can envisage that a type of tyre that would be particularly suitable for wheelbarrows, but far cheaper than the conventional type of tyre, would be desirable. According to the present invention there is provided a tyre comprising a hollowtoroidal inflatable elementwherein the intersection of the tyre with any plane including the tyre axis defines a closed line having a semi-circular part and another curved symmetrical part comprising two flexures which define a bulging lobe, an inflation valve being provided in the hollowtoroidal element. The invention will be now further described, by way of illustrative and non-limiting example, with reference to the accompanying drawing, in which: Figure 1 is the side view of a tubeless tyre embodying the invention; and Figure 2 is the plan view, partially in section, of the tyre Figure 1. Atyre 1 shown in the drawing comprises a tubular toroidal chamber or element 2 (Figure 2) of closed section having on its outer side a semi-circular section and, on its inner side, a symmetrical curved section wherein two opposing flexures 3 and 4form a central bulging lobe 5. A series of grooves 6, lying in planes perpendicular to the axis 7 of the wheel, are made along the semi-circular outer side to afford a tread pattern. An inflation or air valve 8 of a known type is housed on the inner part, preferably (as shown) in correspondence with the lobe 5. Different materials may be employed in the making of the chamber or element 2 of the tyre, though many tests has shown that a plastics material (preferably polyvinyl chloride (PVC)) is most suitable in that its life is substantially the same as that of the traditional tyres made of rubber and cloth, it easily endures the generally minimal stress to which it is subjected, and its production cost is lower than that of the conventional tyres. The tyre 1 is mounted directly on a wheel rim and thereafter inflated. Due to the inflation pressure, the chamber 2, which was previously floppy, takes on the shape indicated in Figure 2 and the bulging lobe 5 fits into the inner walls of the rim, exerting against them a pressure sufficient to clamp the tyre in place and prevent it from moving with respect to the rim. The tyre 1 can thus offer the advantages of quick and easy mounting, and of costing a lot less than traditional tyres due to the absence of an inner air tube, to the use of plastics material much cheaper than rubber, and to the use of a chamber without reinforcement cloth and/or steel wires, whereby the manufacturing process is much easier, quicker and cheaper. CLAIMS

1. A tyre comprising a hollow toroidal inflatable element wherein the intersection of the tyre with any plane including the tyre axis defines a closed line having a semi-circular part and another curved symmetrical part comprising two flexures which define a bulging lobe, an inflation valve being provided in the hollowtoroidal element.

2. Atyre according to claim 1, wherein the toroidal element is of plastics material.

3. A tyre according to claim 2, wherein the plastics material is polyvinyl chloride.

4. A tyre according to any one of the preceding claims, having on an outer part thereof a series of grooves or the like which afford a particular tread pattern.

A tyre substantially as herein described with reference to the accompanying drawing.

6. Awheel including a tyre according to any one of the preceding claims.

7. A wheelbarrow incorporating a wheel according to claim 6.