GB2054482A

GB2054482A - Pneumatic tyre

Info

Publication number: GB2054482A
Application number: GB7924619A
Authority: GB
Original assignee: NICHOL GOLF EQUIPMENT Ltd
Current assignee: NICHOL GOLF EQUIPMENT Ltd
Priority date: 1979-07-14
Filing date: 1979-07-14
Publication date: 1981-02-18
Also published as: ZA804211B

Abstract

A pneumatic tyre, for example for a golf trolley, comprises a plastics material circular sleeve 11 having a raised rim 15 centrally located on the inner circumference 12 of the tyre. Gripping members 18 are located on each side of the rim 15 and serve to grip the hub to which the tyre will be fitted. The tyre can be manufactured by rotational moulding, in which liquid plastics material is placed in a mould of two or three pieces, and the mould is rotated simultaneously about two axes at an increased temperature. The tyre would normally be made from a flexible plastics material to enable it to fit a variety of different hubs. <IMAGE>

Description

SPECIFICATION Pneumatic tyre The present invention relates to tyres, and is particularly but not exclusively, concerned with tyres for golf trolleys.

In the past golf trolleys have usually been provided with solid or holomatic tyres of a rubber-like material, or tyres made of foam plastic material. If they are solid they are either narrow, which marks the golf course, or wide, heavy and cumbersome.

According to one aspect of the present invention there is provided a pneumatic tyre comprising a plastics material circular sleeve having a raised rim centrally located on the inner circumference thereof and gripping members located on either side of the rim.

The design and shape of the tyre together with the plastics material selected enable the tyre to be sufficiently flexible to fit a range of wheel rims.

Advantageously the gripping members are in the form of outwardly directed grooves which may be formed either by providing raised gripping portions at predetermined intervals around the rim, or by providing grooves in a thicker wall area each side of the rim.

In another aspect of the invention there is provided a pneumatic tyre comprising a plastics material circular sleeve having a raised rim centrally located on the inner circumference, an area on each side of the rim being thicker in wall section than the remainder of the sleeve in order to tolerate wear from a wheel rim to which the tyre is to be fitted.

Preferably the tyre has a circumferentially grooved tread of dimensions which resist dirt accumulation.

The invention will now be described, byway of example, with reference to the accompanying drawings, in which Figure 1 is a perspective view of a first embodiment of the invention, Figure 2 is a perspective view of a second embodiment of the invention, and Figure 3 is a cross-section view of the embodiment of Figure 1 fitted to a wheel rim.

The tyres illustrated are designed to fit a range of wheel rims and each comprise a circular sleeve 11 having an inner circumferential wall 12 and an outer circumferential wall 13. The outer wall is grooved circumferentially to provide a tread 14 designed to repel dirt.

A circular raised rim 15 centrally located on the inner wall 12, is integral with the sleeve, and is hollow (see Figure 3). The rim slots into the rim 16 of a wheel to which the tyre is to be fitted. Part of the rim 15 and an area 17 adjacent the rim 15 is provided with gripping members 18. These may be in the form of raised finger portions 19, as shown in Figure 2, or of raised portions created by serrating or notching a thicker area, as shown in Figure 1. The gripping members 18 are not essential where the tyre is fitted on a wheel of optimum size, but are important to provide a grip on the wheel where a smaller or larger than optimum wheel is used. The extra wall thickness in the inner wall created by the gripping members 18 on each side of the rim 15 helps to tolerate wear on the tyre by the wheel rim 16.

The tyre has a valve 22 (Figure 1) in a side wall 23 of the sleeve 11 to enable air to be introduced to the hollow for inflation.

The tyres are produced by a rotational moulding process in which liquid plastics material is introduced into a space between two or three mould pieces, the mould pieces closed and the mould rotated simultaneously about two axes. Gravitational forces urge the liquid to the edge of the mould and simultaneous heating of the mould sets the liquid to form a tyre.

The plastics material used should be selected to produce a tyre that is sufficiently flexible to fit over a range of wheel rims. Plasticised P.V.C. has been used successfully but it is envisaged that various other plastics such as thermoplastic rubber, polythene, ethylene vinyl acetate or polyester could be used. These materials would be unlikely to be suitable for high speed or heavy duty tyres.

At the moment the tyre is made in two sizes to fit a range of wheel rims from 71/2 inches to 91/2 inches.

The tyre is fitted to the wheel uninflated, the outer wall 13 being concave. The tyre is inflated after fitting by using a bicycle pump with a football adaptor. When inflated, the outer wall 13 should be flat, as shown in Figure 3. The tyre is overinflated if the surface of the outer wall becomes convex.

The tyres are advantageously injected with puncture-proofing.

The tyres can be made about 4 inches wide, and in use will form a flat area of contact which spreads the load. For example where a solid tyre of the same width would produce a pressure of 14 psi, a pneumatic tyre according to the present invention would produce a pressure of about 2.2 psi. This obviously reduces the evidence of trolley passage over the golf course.

The plasticised P.V.C which has been successfully used in the rotating metal mould process is mainly a mixture of polyvinyl chloride polymer (resin) and liquid phthalate type plasticiser. The mixture also contains ingredients to prevent degradation by the heating process and to add pigmentation. A typical formula would be PVC 65%, liquid plasticiser 28%, heat stabiliser 5%, pigment 1% and additives 1%.

1. A pneumatic tyre comprising a plastics material circular sleeve having a raised rim centrally located on the inner circumference thereof.

2. Atyre according to claim 1 including gripping members located on each side of the rim for engagement with the hub to which the tyre will be fitted for use.

3. A tyre according to claim 1 or 2 wherein an area on each side of the rim is thicker in wall section than the remainder of the sleeve.

4. A tyre according to claims 2 and 3 wherein the gripping members are produced by forming grooves in the thicker wall area to leave raised gripping portions.

5. A tyre according to claim 2 whereing the

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Pneumatic tyre The present invention relates to tyres, and is particularly but not exclusively, concerned with tyres for golf trolleys. In the past golf trolleys have usually been provided with solid or holomatic tyres of a rubber-like material, or tyres made of foam plastic material. If they are solid they are either narrow, which marks the golf course, or wide, heavy and cumbersome. According to one aspect of the present invention there is provided a pneumatic tyre comprising a plastics material circular sleeve having a raised rim centrally located on the inner circumference thereof and gripping members located on either side of the rim. The design and shape of the tyre together with the plastics material selected enable the tyre to be sufficiently flexible to fit a range of wheel rims. Advantageously the gripping members are in the form of outwardly directed grooves which may be formed either by providing raised gripping portions at predetermined intervals around the rim, or by providing grooves in a thicker wall area each side of the rim. In another aspect of the invention there is provided a pneumatic tyre comprising a plastics material circular sleeve having a raised rim centrally located on the inner circumference, an area on each side of the rim being thicker in wall section than the remainder of the sleeve in order to tolerate wear from a wheel rim to which the tyre is to be fitted. Preferably the tyre has a circumferentially grooved tread of dimensions which resist dirt accumulation. The invention will now be described, byway of example, with reference to the accompanying drawings, in which Figure 1 is a perspective view of a first embodiment of the invention, Figure 2 is a perspective view of a second embodiment of the invention, and Figure 3 is a cross-section view of the embodiment of Figure 1 fitted to a wheel rim. The tyres illustrated are designed to fit a range of wheel rims and each comprise a circular sleeve 11 having an inner circumferential wall 12 and an outer circumferential wall 13. The outer wall is grooved circumferentially to provide a tread 14 designed to repel dirt. A circular raised rim 15 centrally located on the inner wall 12, is integral with the sleeve, and is hollow (see Figure 3). The rim slots into the rim 16 of a wheel to which the tyre is to be fitted. Part of the rim 15 and an area 17 adjacent the rim 15 is provided with gripping members 18. These may be in the form of raised finger portions 19, as shown in Figure 2, or of raised portions created by serrating or notching a thicker area, as shown in Figure 1. The gripping members 18 are not essential where the tyre is fitted on a wheel of optimum size, but are important to provide a grip on the wheel where a smaller or larger than optimum wheel is used. The extra wall thickness in the inner wall created by the gripping members 18 on each side of the rim 15 helps to tolerate wear on the tyre by the wheel rim 16. The tyre has a valve 22 (Figure 1) in a side wall 23 of the sleeve 11 to enable air to be introduced to the hollow for inflation. The tyres are produced by a rotational moulding process in which liquid plastics material is introduced into a space between two or three mould pieces, the mould pieces closed and the mould rotated simultaneously about two axes. Gravitational forces urge the liquid to the edge of the mould and simultaneous heating of the mould sets the liquid to form a tyre. The plastics material used should be selected to produce a tyre that is sufficiently flexible to fit over a range of wheel rims. Plasticised P.V.C. has been used successfully but it is envisaged that various other plastics such as thermoplastic rubber, polythene, ethylene vinyl acetate or polyester could be used. These materials would be unlikely to be suitable for high speed or heavy duty tyres. At the moment the tyre is made in two sizes to fit a range of wheel rims from 71/2 inches to 91/2 inches. The tyre is fitted to the wheel uninflated, the outer wall 13 being concave. The tyre is inflated after fitting by using a bicycle pump with a football adaptor. When inflated, the outer wall 13 should be flat, as shown in Figure 3. The tyre is overinflated if the surface of the outer wall becomes convex. The tyres are advantageously injected with puncture-proofing. The tyres can be made about 4 inches wide, and in use will form a flat area of contact which spreads the load. For example where a solid tyre of the same width would produce a pressure of 14 psi, a pneumatic tyre according to the present invention would produce a pressure of about 2.2 psi. This obviously reduces the evidence of trolley passage over the golf course. The plasticised P.V.C which has been successfully used in the rotating metal mould process is mainly a mixture of polyvinyl chloride polymer (resin) and liquid phthalate type plasticiser. The mixture also contains ingredients to prevent degradation by the heating process and to add pigmentation. A typical formula would be PVC 65%, liquid plasticiser 28%, heat stabiliser 5%, pigment 1% and additives 1%. CLAIMS

5. A tyre according to claim 2 whereing the gripping members are formed as raised portions which extend outwardly of the rim.

6. A tyre according to any of the preceding claims wherein the plastics material used is plasticised polyvinyl chloride.

7. Atyre according to claim 6 whereing the plasticiser is of a liquid phthalate type.

8. A tyre according to claim 4 wherein the constituents are PVC 65%. liquid plasticiser 28%, heat stabiliser 5% and additives 2%.

9. A pneumatic tyre substantially as herein described with reference to the accompanying drawings.

10. A method of manufacture for a tyre according to any of the preceding claims, wherein liquid plastics material is introduced into a space between two or three mould pieces, the mould pieces closed, and the mould rotated simultaneously about two axes at an increased temperature.