GB2077395A - Tyre pressure indicating dust caps - Google Patents

Abstract

A tyre valve dust cap incorporates co-operating parts (1) and (2) of a tyre pressure selection indicator which by relatively displacing these components can be set to indicate the correct pressure of the tyre. <IMAGE>

Description

SPECIFICATION Tyre pressure indicating device This invention relates to a tyre pressure indicating device.

It is important for safety and other reasons, that pneumatic tyres of vehicles be inflated to correct pressures. However the correct pressures of the tyres of any given vehicle are often not known or present to the mind of the vehicle owner or other person wishing to check or inflate the tyres. In order to avoid this circumstance it has been proposed to display a number representing the correct tyre pressure on each vehicle wheel or on a disc carried by the tyre valve dust cap.

The foregoing proposals do not provide or do not conveniently provide for variation of the display and it is an object of the present invention to provide a device which affords an advantage in this respect According to the present invention there is provided a tyre valve dust cap incorporating relatively displaceable components which form co-operating part of a tyre pressure selection recorder which by relatively displacing said components can be set to indicate any one of a plurality of different tyre pressure values.

A dust cap according to the invention can be marketed as an accessory suitable for various user requirements. And a user can at any time easily alter the register if required, e.g. when fitting the cap to the valve of a different tyre or when a given tyre is inflated to an above-normal pressure suitable for prolonged high speed travel.

The cap is preferably provided with a female screw profile enabling it to be screwed onto a standard tyre valve. But the cap can as an alternative be formed for connection to a tyre valve in some other manner.

Preferably the recorder is of dial form, i.e.

incorporates numbers distributed around an axis of the cap, and the said cap components are relatively angularly displaceable about such axis for varying the setting of such recorder.

In certain very advantageous embodiments of the invention the said components car be relatively rotated for varying the setting of the recorder, without separating such components.

Such components can be relatively rotatable against a frictional resistance sufficient to prevent inadvertent relative displacement thereof, e.g.

under the action of vibration. However it is preferred for at least part of one or each component to be elastically deformable and for the components to be shaped with portions which by elastic recovery forces automatically interlock to prevent such inadvertent displacement, as the components are brought into any of their relative positions corresponding with the different recorder settings.

It is very suitable for the said cap components or at least one of them to be wholly or partly elastically deformable and for the components to be shaped for coupling by direct snap-fastening one into the other. For example one component may comprise an axial boss which is elastically deformable for snap-fitting into an under-cut recess or bore of the other component.

Preferably the components or one of them is made of synthetic polymeric material. By way of example, one or each of the components can be a one-piece moulding. A very suitable material for such moulding is nylon.

The recorder may comprise, for example, a series of pressure values distibuted as a series on one of the components, and an arrow, cursor or other marker on the other component. In one particularly favoured form of the invention the cap comprises a body component carrying a series of numbers and a top component which is formed with an opening or window and is rotatable relative to said body component to expose any of said numbers through said cut-out or window.

Preferably said numbers are distributed on the top face of the body component, around its axis.

In the interest of versatility it is preferable for the tyre pressure selection recorder to cover a range of at least six different pressure values, and most preferably a range of ten or more such values, In certain dust caps according to the invention the recorder provides a plurality of pre-selectable pressure values each represented by two digits (e.g. a tens digit and a units digit) which are provided on different ones of the said relatively displaceable cap components. For example one of said components bears the digit 2 representing tens and the other component bears digits 0 to 9 representing units so that by relatively displacing the components they can be relatively positioned to represent any of the values 20 to 29.The said feature which lies in the provision of digits of different unit value on different components can be incorporated in a very convenient manner if one of the dust cap components has an opening or window through which any selected digit on the other component can be exposed. For example in a cap constructed in that manner a digit representing tens, units or fraction units (e.g.

tenths) can be located on said one component, adjacent the opening or window, so that it can be positioned for reading in combination with a selected digit of different unit value on the other component.

By allocating digits of different unit value to different components as above referred to a series of pressure values covering a range wide enough to suit any standard private or any commercial vehicle can be provided on a dust cap of very modest dimensions, e.g. a cap having a diameter of about 14mm.

In a particularly beneficial embodiment of the invention wherein digits of different unit value are allocated to different components as above referred to, one of the components is formed for releasably coupling to the other component in either of two mutually inverse orientations and is angularly displaceable relative to said other component in either of such orientations, and said one component bears different digits on its opposite sides. It will readily be apparent that by that means the recorder can cover a still wider range of pressure values without having to increase the size of the cap.For example if the said one component bears the tens digits 2 and 3 on its opposite sides and the other component bears the units digits 0 to 9 then in one orientation of the tens digit-bearing component the recorder can be set to indicate any of the values 20 to 29 and in the other orientation of such component the recorder can be set to indicate any of the values 30 to 39. (A similar construction can be used when employing units and tenths digits instead of tens and units).

A cap having a recorder covering the pressure values 20 to 39, taken as indicating Ibs/in-2, is suitable for use with almost all types for currently marketed private automobiles. For commercial vehicle tyres, pressures ranging in increments of 5 units from 10 to 95 Ibs/in-2 are used. A cap according to the present invention can incorporate a recorder covering that range. For example one component can bear the units digits 0 and 5 either of which can be brought into association with any of the tens digits 1 to 9, the latter being provided on the other component.

It is of course not necessary for the tyre pressure selection recorder of a cap according to the invention to bear numbers appropriate for indicating tyre pressures in pounds per square inch. Other pressure units can be provided for. For example the cap can bear digits appropriate for indicating pressures in bars. In such a cap the recorder may for example provide for pressure selections ranging, in increments of 0.1 bars, from 1 to 1.9 bars or from 2.0 to 2.9 bars. Or a pressure selection ranging, in increments of 0.5, from 0 to 9.5 bars can be provided for by placing the tenths digit 0 and 5 on one component for bringing either of such digits into association with the units digits 0 to 9 on the other component.

An embodiment of the invention, selected by way of example, will now be described with reference to the accompanying drawings in which Fig. 1 is an exploded perspective view of the components of the dust cap and Fig. 2 is a plan view of the assembled cap components in a particular setting.

The illustrated cap comprises a body component 1 and a top component 2, each of which is a one-piece injection moulding of nylon.

The component 1 has a socket 3 in which a thread can be formed by screwing the component onto a conventional pneumatic tyre valve. In the top portion of the said body component there is an axial recess 4 shaped to provide adjacent its entrance an undercut face 6. Engraved or moulded digits 0 to 9 are displayed on the top face of the component 1, these digits being distrubuted around the recess 4. The top face of said component is shaped to provide a radial triangular-section groove such as 7 between each neighbouring pair of said digits.

The top component 2 comprises a disc portion 8 with a sectoral opening 9 and integral axial bosses 10 and 11 projecting from opposit faces of the disc. Each boss comprises two opposed portions separated by a diametral slot 12 or 13.

On one side of the disc portion 8 there is the digit 2 adjacent one boundary of said opening 9 and an integral triangular section rib 14 adjacent the opposite boundary of such opening. The other side of the disc bears the digit 3 (not shown) and a corresponding rib 1 5 adjacent opposite boundaries of the said opening.

The components can be assembled by pushfitting the boss 11 into the recess 4 in the body component. when the top component is angularly positioned so that one of the digits on the body component is exposed centrally through the opening 8 in the top component, the rib 1 5 occupies one of the radial grooves such as 7 in the top face of the body component. In such a position the top of the cap displays, as for example is shown in Fig. 2, a two-digit number formed by the combination of the tens digit 2 on the top component with the digit exposed through said opening. The top component can by applying sufficient turning moment to cause the rib to ride out of the groove, be turned relatively to the body component into a different setting in which any of the other digits on the body component is exposed -through the opening.Consequently the top component can be set so that the cap displays any of the values 20 to 29. The boss 11 remains captive in the recess 4 during such rotations of the top component. The necessary force for turning the top component relative to the body component can be applied to the top boss 10 by means of a coin inserted in the slot 12.

If it is desired to set the recorder to indicate any of the numbers 30 to 39 the top component is pulled out of ths recess 4 in the body component and reinserted in inverted orientation, i.e., so that the boss 10 enters the recess and the tens digit 3 on the top component is displayed to view. The top component can then, as before, be turned to expose any of the units digits through the opening 8.

In a modification (not shown) of the illustrated cap, the top component 2 is provided with a transparent window instead of the opening 9.

In another modification the grooves 7 and ribs 14 are replaced by recesses and dimples.

Claims (12)

1. A tyre valve dust cap incorporating relatively displaceable components which form co operating parts of a tyre pressure selection recorder which by relatively displacing said components can be set to indicate any one of a plurality of different tyre pressure values.

2. A cap according to claim 1, wherein the recorder incorporates numbers distributed around an axis of the cap and said cap components are relatively angularly displaceable about an axis of the cap for varying the setting of such recorder.

3. A cap according to claim 2, wherein the said cap components can be relatively rotated without separating them.

4. A cap according to claim 3, wherein at least part of one or each component is elastically deformable and the components are shaped with portions which by elastic recovery forces automatically interlock to prevent inadvertent relative displacement of said components, as they are brought into any of their relative positions corresponding with the different recorder settings.

5. A cap according to any preceding claims, wherein the components are formed for direct snap-fastening one into the other.

6. A cap according to claim 5, wherein the said on component comprises an axial boss which is elastically deformable for snap-fitting into an under-cut recess or bore provided in the other component.

7. A cap according to any preceding claim, wherein each of said components is a one-piece moulding ef synthetic polymeric material.

8. A cap according to any preceding claim, wherein one said component (hereafter called "body component") carries a series of numbers and the other component (hereafter called "top component") is formed with an opening or window and is rotatable relative to said body component to expose any of said numbers through said cut-out or window.

9 A cap according to any preceding claim, wherein the recorder provides a plurality of preselectable pressure values each representated by two digits (e.g. a tens digit and a units digit) which are provided on different ones of the said relatively displaceable cap components.

10. A cap according to claims 8 and 9, wherein a digit representing tens, units or fraction units is located on said top component, adjacent said opening or window, for reading in combination with a selected digit (of different unit value) on said body component.

1 A cap according to claim 9 or 10, wherein one of said components is formed for releasable coupling to the other components in either of two mutually inverse orientations and is angularly displaceable relative to said other component in either of such orientations, and said one component bears different digits on its opposite sides.

12. A tyre valve dust cap substantially as herein described with reference to and as illustrated in the accompanying drawings.