GB2270382A

GB2270382A - A gauge

Info

Publication number: GB2270382A
Application number: GB9318579A
Authority: GB
Inventors: John Dudley William Carass; David Michael Carass
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-09-08
Filing date: 1993-09-08
Publication date: 1994-03-09
Also published as: GB9219039D0; GB9318579D0

Abstract

A gauge enabling a predetermined proportion of the width of an object to be determined, comprising first means alignable with the outer dimensions of the object to be gauged and second means associated with the first which directly defines said predetermined proportion of the object. Preferably the gauge comprises centring means (16) provided to aid in centring the gauge on the object to be gauged. The gauge may be used in determining the centre three - quarters of the tread of a tyre. The outer edges (2,3) are aligned with the outer edges of the contact tread of the tyre. A mark may then be made on each side of the tyre at a corresponding position on the inner edges (4, 5). The inner edges (4, 5) are positioned at a fixed pre-determined ratio of the total distance between the outer edges (2, 3). <IMAGE>

Description

TITLE: A GAUGE DESCRIPTION: This invention relates to a gauge, more particularly, but not exclusively, for measuring the width of tyre treads.

There is a legal requirement in the United Kingdom for the centre three quarters of the contact tread of a tyre for a motor vehicle to have a minimum tread depth. The only means presently available -for determining the centre three quarters of the contact tread of a tyre is to use a measuring device such as a ruler or a tape measure. The problem with using such a device is that calculations need to be made to determine the centre three quarters of the measured width.

There is thus a need for a simple but effective device for determining tyre tread widths.

Accordingly the present invention provides a gauge enabling a predetermined proportion of a linear dimension of a thing to be determined, comprising first means alignable with the outer limits of the thing to be gauged and second means associated with the first means and which directly defines said predetermined proportion of the thing.

Preferably centring means is provided to aid in centring the gauge on the thing to be gauged.

In relation to gauging tyre tread widths the present invention provides a tyre tread width gauge comprising a flexible member of sheet material adapted to be placed over a portion of a tyre tread, the member having a pair of symmetrically diverging outer edges and a corresponding pair of symmetrically diverging inner edges, the distance between each outer edge and its corresponding adjacent inner edge at any position along them being a fixed predetermined ratio of the distance between the outer edges at that position.

In this connection the word edge may cover a continuous edge or a discontinuous edge, e.g. that provided by a series of slots or perforations. Preferably the inner and outer edges are straight lines.

Generally the member is provided with centring means to aid in centring the gauge on the tyre. Preferably the member is made of a resilient material.

The member may take several shapes but is preferably generally triangular. It may be made of a plastics material or of metal sheet. When made of plastics, the member may be transparent.

The invention is illustrated, by way of example, in the accompanying drawing in which: Figure 1 shows a front view of a tyre tread width gauge of the invention.

In the drawing there is shown a tyre tread width gauge 1 which is made of a plastics material and is shaped as an isosceles triangle. The gauge 1 has two outer edges 2,3 and two adjacent inner edges 4,5 on the upright sides of the triangle. The straight line distance between the outer edges 2,3 correspond to different widths of contact tread provided on different sizes of tyre. The inner edges 4,5 are positioned at a fixed pre-determined ratio of the total distance between the outer edges 2,3 of the upright sides.

A centre line 6 is provided to enable the centring of the gauge on the tyre. A series of straight lines 7 are provided between the outer and inner edges to enable a position on an inner edge corresponding to a position an outer edge to be located. A centimetre scale 8 is provided at the base of the gauge to aid with the correct positioning of the device on the tyre.

In the drawing the gauge 1 is in skeleton form, i.e.

the centre of the gauge 9 is hollow. However, the gauge may have a solid centre and the inner edges 4,5 may be in the form of slots or a series of perforations.

It will of course be appreciated that the gauge does not have to be triangular and may take several shapes.

In use the gauge is placed on the surface of the tyre with the centre line 6 running circumferentially and central to the tread. On aligning the outer edges of the upright sides of the triangle 2,3 with the outer edges of the contact tread, a mark is made on each side of the tyre at a position on the inner edges 4,5 perpendicular to the outer edges of the contact tread.

The specific embodiment thus provides a tyre tread width gauge which is effective, but inexpensive and simple to use.

Claims

1. A gauge enabling a predetermined proportion of a linear dimension of a thing to be determined, comprising first means alignable with the outer limits of the thing to be gauged and second means associated with the first means and which directly defines said predetermined proportion of the thing.

2. A gauge according to claim 1, wherein centring means is provided to aid in centring the gauge on the thing to be gauged.

3. A tyre tread width gauge comprising a flexible member of sheet material adapted to be placed over a portion of a tyre tread, the member having a pair of symmetrically diverging outer edges and a corresponding pair of symmetrically diverging inner edges, the distance between each outer edge and its corresponding adjacent inner edge at any position along them being a fixed pre-determined ratio of the distance between the outer edges at that position.

4. A gauge according to Claim 3, wherein the inner and outer edges are straight lines.

5. A gauge according to Claims 3 or 4, wherein the member is made of a resilient material.

6. A gauge according to any one of Claims 3, 4 or 5, wherein the gauge is generally triangular in shape.

7. A gauge according to Claims 6, wherein the triangle is an isosceles triangle and wherein centring means is provided to aid in centring the gauge on a tyre, the centring means being disposed on the bisector line.

8. A gauge according to Claim 6 or 7, wherein the gauge is shaped as an isosceles triangle with adjacent sides forming the said outer edges and wherein the gauge is formed with a symmetrically positioned cut-out portion which is generally triangular, the adjacent sides of which form the said inner edges.

9. A gauge according to Claims 7 or 8, wherein a series of lines perpendicular to the bisector line of the triangle are provided between the outer and inner edges of the triangle.

10. A gauge as herein before described with reference to and as illustrated in the accompanying drawing.