GB2273361A

GB2273361A - Tyre tread gauge

Info

Publication number: GB2273361A
Application number: GB9222441A
Authority: GB
Inventors: Stephen Martin Glazzard; Alan Edwards; Roger Victor Frederick Smith
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-10-24
Filing date: 1992-10-24
Publication date: 1994-06-15
Also published as: GB9222441D0

Abstract

A tyre tread gauge relates to a gauge or to a set of gauges for determining the depth of tyre tread over a portion of the tyre width as prescribed by motor transport regulations. Each gauge comprises an inner surface corresponding to the shape of a tyre. The gauges may have fixed legs or movable jaws (3a) for attaching the gauge over a tyre. A depth gauge is moveable along the tyre tread gauge in a slot or groove. <IMAGE>

Description

The invention relates to a gauge or to a set of gauges for determining the minimum depth of tyre tread over a percentage of tyre width as prescribed by motor transport regulations and law. A gauge according to the invention included two faces which approximate to the total width of the functional tyre tread of said tyre with an indicated symmetrical centre portion (as prescribed by regulation) corresponding to the area for which the depth (minimum) of the tread must be gauged for the requirement of law. This will be accomplished by using a depth gauge over the indicated centre portion to ascertain that the tyre is of sufficient tread depth as to satisfy the aforementioned minimum depth regulations.

Preferably the gauge will have a slot or bar across the regulation centre portion into which a depth gauge may be fitted thereby limiting the gauged depth to the regulated area. Conveniently the slot or bar will have stop to restrain the depth gauge from encroaching into the outer areas to which regulations does not apply.

In the event of a gauge set ie for varying width of tyres, the groove slot or bar will correspond to the same percentage of tyre width throughout (as per regulation). Desirably the gauging would be carried out by an adjustable version of the previously described set of gauges, adaptable for a range of tyre widths corresponding to the type of tyres prescribed by regulations.

One example of gauging regulation depths over the required centre portion is illustrated in Fig. 1 this shows an example of a typical gauge from a gauge set. Fig. 2 shows an example of a gauge set incorporating a bar groove or slot acting as a guide for the addition of a depth gauge, Fig. 3 shows an adjustable gauge for eliminating the need for a set of gauges, Fig. 4 shows an adjustable gauge with the addition of a depth gauge.

Fig. 5 shows a gauge in operation with indicated areas for which the depth gauge is to be used over.

Referring to the drawing Fig. 1 the gauge comprises of a flat plate in metal, plastic or any material with stability to satisfy the tolerances required by regulations. The plate contains an inner form which, (a) corresponds to the width of tyre to be gauged, (b) to the symetrical centre portion over which the depth tread is to be assertained, (d) sufficient depth to ensure that the width of the tyre is totally incorporated, (e) is a stop to ensure that the gauge sits at 90" to the diameter of the tyre, (f) is clearance over the centre portion of the tyre in excess of the gauged portion and, (c) is the outer form which may be of any shape for convenience with or without handle.

Fig. 2 shows a gauge similar to that shown in Fig. 1 but with the addition of a tyre tread depth gauge, (2a) the depth gauge is located in a cradle, (2b) which allows movement of the tyre depth gauge in a vertical direction, (2c) the cradle is located, in turn, in a slot, bar or groove, (2d) which will allow horizontal movement of the depth gauge over the central portion of the tyre to be measured, the bar, slot or groove will be of sufficient length and or will have stops as to limit the horizontal movement to the required gauging distance and position.

Fig. 3 shows an adjustable type of gauge which consists of moveable "jaws" (3a) which are adjustable to the total width of the tyre to be gauged, (3a) a second paid of moveable jaws (3b) which are adjustable to the percentage of the tyre width to be gauged (jaws (3b) are set and locked manually or automatically adjusted to the required width by the action of moving jaws (3b) into position).

Fig. 4 is similar to Fig. 3 but with the addition of a depth gauge the operation of this is identical to that previously described in Fig. 2, except that the slot bar or groove and the appropriate length and or stops will be adjustable in respect to the outer jaws (4a).

Fig. 5 shows the operation using the gauge (type shown in Fig.

1) in conjunction with a tyre depth gauge. The gauge is placed across the tyre as shown and the depth of tyre tread is gauged in the indicated region (5b).

It will be appreciated that the depth gauge may be confined within the appropriate area similar to that described in Fig.

2.

It will also be appreciated that the tyre depth gauge may be used in conjunction within the indicated area in the variable gauge described in Figure 3 or within the variable confines of the gauge shown in Figure 4.

Claims

What we claim is:

1. a gauge or set of gauges encompassing all common widths of tyre design all of which have a centre portion indicating the portion of tyre width over which the tyre depth must be gauged in accordance with motor transport regulations.

2. a gauge or set as claimed in Claim 1. where in or where on a groove bar or slot into or onto which a tyre depth gauge is fitted, thereby limiting the travel of the tyre depth gauge to the centre portion of the tyre required to be measured for depth. The tyre gauge will be adjustable in a vertical position relative to the face of the gauge/gauges to accommodate different tyre forms and wear.

3. the operational use of a gauge or gauge set described in Claim 1. or Claim 2. for gauging a tyre depth over that portion across the tread form prescribed by law or regulations.

4. the operational use of a gauge as described in Claim 3.

but using an adjustable gauge shown in Fig. 3.

5. the operational use of a gauge as described in Claim 4.

but utilising an adjustable slot bar or groove within the symetrical position prescribed by law or regulations.

6. the operational use of a gauge as described in Claim 4.

of which the adjustment is carried out manually.

7. the operation of a gauge as described in Claim 4. of which the adjustment is carried out automatically.

8. the operation of a gauge as described in Claim 6. but with the addition of a tyre tread depth gauge.

9. the operation of a gauge as described in Claim 7. but with the addition of a tyre tread gauge.