GB2162288A

GB2162288A - Valves for vehicle tyres

Info

Publication number: GB2162288A
Application number: GB8515418A
Authority: GB
Original assignee: Alligator Ventilfabrik GmbH
Current assignee: Aigo Tec GmbH
Priority date: 1984-06-18
Filing date: 1985-06-18
Publication date: 1986-01-29
Also published as: FR2565906B1; GB8515418D0; GB2162288B; ES294444Y; FR2565906A1; ES294444U

Abstract

A snap-action valve 10 for a tubeless vehicle tyre comprises a sheathing body 11 of material of limited resiliency such as rubber, which surrounds a valve cylinder 20 having an external screwthread 22 and which body forms an annular edge 17 adjacent the external screwthread 22, characterised in that the annular edge 17 of the sheathing body 11 is covered by a harder ring 40, which surrounds the valve cylinder 20 and protects the annular edge 17 against damage, the ring 40 preferably being embossed and/or impressed as indicated at 46, being of highly contrasting colour to the sheathing body 11 and sticking radially outwardly beyond the adjacent part of the sheathing body 11, to provide visual and tactile assistance in locating and handling the valve 10. <IMAGE>

Description

SPECIFICATION Valves for vehicle tyres The invention relates to valves for vehicle tyres comprising a sheathing body of material of limited resiliency, which surrounds a valve cylinder having an external screwthread and which forms an annular edge adjacent the external screwthread.

Valves of that kind for tubeless vehicle tyres are fixed in respect of dimensions and shape by DIN 7780, a German standard, and can be rapidly fitted into a rim due to the resiliency of the sheathing body, which is preferably made of rubber. A disadvantage which has been found is that it is precisely the necessary resiliency of the sheathing body that results in damage to the annular edge, particularly when the usual valve cap is frequently taken off and put on.

In accordance with the present invention, however, a valve for a vehicle tyre comprises a sheathing body of material of limited resiliency, which surrounds a valve cylinder having an external screwthread and which forms an annular edge adjacent the external screwthread, characterised in that the annular edge of the sheathing body is covered by a ring which surrounds the valve cylinder.

The annular edge of the sheathing body is protected from damage by the ring.

It has been found desirable for the ring to be made from a material which is harder or more brittle than the sheathing body itself in order to enhance the protective function. Preferred materials for the ring are harder plastics or metals.

The ring may be of square or rectangular radial cross-section, and lie on the annular edge.

A preferred embodiment is distinguished in that the ring is of L-shaped radial crosssection, one limb portion thereof forming a cover limb portion bearing against the annular edge to be protected, while the side limb portion which is at a right angle thereto bears against the outside surface of the sheathing body, this embodiment being particularly effective in protecting the corner of the annular edge.

The ring may project radially beyond the outside surface of the sheathing body, and thus radially stick out a little. That configuration, when handling the valve and in particular the valve cap thereof, makes it possible better to find by feel the end of the valve cylinder which projects out of the sheathing body, and thus facilities handling of the arrangement.

The extent to which the arrangement may be more easily handled, as referred to above, may be further enhanced by making the outside surface of the ring different from the outside surface of the sheathing body.

The difference between the two outside surfaces may be produced by embossing and/or impressing the outside surface of the ring, which embossing or impressing may also be for example in the form of letters, the outside surface of the sheathing body usually being smooth. Visual assistance in handling the valve is afforded by the two mutually adjoining outside surfaces being of different colours. As the sheathing body is usually of black rubber, the outside surface of the ring should be of a high-contrast colour or colours, and possibly be fluorescent.

Preferably, the valve cylinder houses a push rod operated valve body with spring return to give a snap action.

Two valves in accordance with the present invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a side view of a first snap-action valve for a vehicle tyre; and Figure 2 is a view in longitudinal section through a second snap-action valve for a vehicle tyre.

Two snap-action valves 10, of a length h of for example 42.5 mm, for tubeless vehicle tyres (not shown) with a tyre pressure of up to 4.2 bars comprise a rubber sheathing body 11 with a dome-like base portion 12, the diameter d of which is greater than the adjoining diameter e of a stem portion 1 3 of the rubber body 11, which is formed in coaxial relationship with the base portion 12, whereby an annular shoulder surface 1 4 is provided around the stem portion 1 3.

At a spacing a above the shoulder surface 14, an annular bead 1 5 projects from the stem portion 1 3. As shown in Fig. 2, when the snap-action valve 10 is fitted into a valve hole 29 in a rim 30, the annular bead 1 5 fits snugly into an annular groove 31 within the hole 29, with the annular shoulder surface 14 bearing against the outside surface 32 of the rim 30.

Carried in an axial passage in the rubber body 11 is a valve cylinder 20 of metal, with an external screwthread 22 associated with the exposed free end 21 thereof. The external screwthread 22 has been shown in Figs. 1 and 2 in a manner often used by engineering draughtsmen. The external screwthread 22 is in fact formed integrally with the valve cylinder 20 and advances helically along the exposed free end 21 thereof.

For the sake of clarity, valve components which are provided within the valve cylinder 20 are only diagrammatically indicated in Fig.

2. The valve components include a valve push rod 23, a valve body 24 and a return spring 25. In the illustrated position, the valve body 24 is closing off a conically tapered valve seat 26 of the valve cylinder 20.

The stem portion 1 3 is formed by a resilient sleeve wall of a gauge b which decreases towards the external screwthread 22 on the valve cylinder 20.

The annular edge 1 7 of the stem portion 1 3 is protected by a ring 40 or 41 of a material which is hard in comparison with the rubber body 11.

As shown in Fig. 1, a ring 40 is of Lshaped radial cross-section, with a cover limb portion 42 and a side limb portion 43. The latter bears against the outside surface 1 8 of the stem portion 1 3 and projects beyond the outside surface 1 8 of the stem portion 13, by its thickness i of for example 0.5 mm. The height k of the ring 40 approximately corresponds to the width n of the shoulder surface 1 4 and preferably measures 2 mm.

Fig. 2 shows a ring 41 of square or rectangular radial cross-section, which is carried on the above-mentioned annular edge 1 7.

The outside surface 45 of the ring 40 or 41, which extends parallel to the axis A of the valve, is provided with embossings or impressions as indicated at 46, and as a result is of a form which differs from the smooth outside surface 18 of the stem portion 1 3. In that way it is possible to feel the protective ring 40 or 41 when unscrewing the valve cap, in order to give improved orientation. A visual distinction between the adjacent outside surfaces 1 8 and 45 is given by different colour ing.

The drawings do not show a valve cap, which is conventional in relation to such valves 10 and is carried on the external screwthread 22.

Claims

1. A valve for a vehicle tyre comprising a sheathing body of material of limited resiliency, which surrounds a valve cylinder having an external screwthread and which forms an annular edge adjacent the external screwth read, characterised in that the annular edge of the sheathing body is covered by a ring which surrounds the valve cylinder.

2. A valve according to claim 1, character ised in that the ring is of a harder material than the sheathing body.

3. A valve according to claim 1 or claim 2, characterised in that the ring is of a more brittle material than the sheathing body.

4. A valve according to any one of claims 1 to 3, characterised in that the ring is of L shaped radial cross-section, wherein one limb portion bears against the outside surface of the sheathing body and the other limb portion bears against the annular edge.

5. A valve according to any one of claims 1 to 3, characterised in that the ring is of square or rectangular radial cross-section, and lies on the annular edge.

6. A valve according to any preceding claim, characterised in that the ring projects radially beyond the outside surface of the sheathing body.

7. A valve according to any preceding claim, characterised in that the outside surface of the ring is different from the outside surface of the sheathing body.

8. A valve according to claim 7, characterised in that the outside surfaces of the ring and the sheathing body are of different colours.

9. A valve according to claim 7 or claim 8, characterised in that the outside surface of the ring is embossed and/or impressed whereas the outside surface of the sheathing body is smooth.

10. A valve according to any one of claims 1 to 9, characterised in that the ring is of metal.

11. A valve according to any one of claims 1 to 9, characterised in that the ring is of plastics.

1 2. A valve according to any preceding claim, characterised in that the sheathing body is of rubber.

1 3. A valve according to any preceding claim, characterised in that the valve cylinder houses a push rod operated valve body with spring return to give a snap action.

14. A valve substantially as hereinbefore described with reference to Fig. 1 or Fig. 2 of the accompanying drawings.