GB2286350A - Upper hook bracket for spraying mould release paint into tyre carcases - Google Patents

Abstract

In the spraying of mould release paint into raw tyre carcases whilst retained by the upper surface (23) of an upper hook bracket (10), the bracket has a nozzle (33) for directing pressurised gas along the lower surface (24) of the bracket to prevent collection of paint thereon. The nozzle (33) comprises a metal lip (32). Gas is supplied via a passage (28) which also feeds downwardly-directed nozzles (29, 30). <IMAGE>

Description

APPARATUS AND METHOD FOR TYRE PAINTING This application relates to tyre painting machines and particularly but not exclusively to those machines designed specifically to apply moulding release paint in the form of a spray to the interior region of raw tyres before the vulcanisation process.

Such tyre spray painting machines are available from KOSEI GIKEN CO LIMITED and TSUBAKIMOTO MACHINERY & ENGINEERING, both of Japan. Shown in Figure 1 is a schematic diagram of a typical tyre painting machine comprising a first station 1 for receiving and forwarding a raw tyre carcass 3 to a painting station 2. The lower bead region 4 of the raw tyre is held by rotatable and radially movable lower hook brackets 5. The upper bead region 6 of the raw tyre is held by upper hook brackets 7 which are lowered in a radially contracted state on a carrier 8 into the upper region of the interior of the raw tyre.

The upper hook brackets 7 are then moved outwardly in the tyre radial direction to engage the upper bead region 6 and then upward by a small distance to expand the raw tyre carcass in its axial direction.

Paint is then applied in a thin film to the interior of the raw tyre by an applicator (not shown) which may be of a rotating spray nozzle or high speed rotating disc type.

A major problem with such conventional tyre painting machines is that excess paint sprayed on to the exterior surface of the upper hook brackets 7 collects on the bottom surface of the brackets and drips on to the lower part of the tyre interior causing problems in the subsequent tyre vulcanising process.

It is an object of the present invention to improve the performance of tyre painting machines by preventing the dripping of excess paint from the upper hook brackets.

According to one aspect of the present invention an upper hook bracket for a tyre spray painting machine is provided having an upper tyre retaining surface and a lower surface adjacent thereto characterised by at least at the lower surface means to direct pressurised gas along said lower surface so as to prevent the collection of tyre paint on said surface.

Preferably the. means comprises a hole through the lower surface connected by a passage in the main hook bracket body to a source of pressurised gas.

More preferably more than one said hole is provided in the lower surface.

The holes preferably have an aperture adapted to direct the pressurised gas along the lower surface.

This may be by means of the hole at the lower surface being provided at an acute angle of less than 100 to the lower surface or by means of a metal lip to direct the pressurised gas along the lower surface.

Preferably the direction of gas flow is radially outwards of the tyre but the important feature is that the flow is along the surface of the hook so as to blow off excess paint and prevent drops forming thereon.

Another aspect of the invention provides a method of painting a tyre comprising supporting the tyre on at least three hook brackets of the type above and supplying pressurised gas to the lower hook surface to blow tyre paint from said lower surface and thus prevent paint build up.

The gas may be any suitable gas but preferably it is air or nitrogen.

Further aspects of the present invention will become apparent from the following description by way of example only, of one embodiment in conjunction with the following drawings in which: Figure 1 is a schematic diagram showing a conventional raw tyre interior paint spraying machine; Figure 2 is a schematic drawing showing further detail of the conventional upper bracket hook of Figure 1; Figure 3 is a schematic diagram showing details of an upper bracket hook according to the present invention; and Figure 4 is a schematic drawing of the tyre engaging hook portion of the upper bracket hook of Figure 3 viewed in the direction of arrow V.

Figure 2 shows details of the conventional upper hook bracket 7 of the conventional raw tyre interior spraying machine shown in Figure 1. As explained above the problem with this prior art bracket is that in use paint sprayed on to the exterior surface 11 and particularly on to the lower portion of the exterior surface during the tyre painting operation collects on the bottom surface 12 and subsequently drips on to the upward facing bottom surface of the tyre interior.

As shown in Figure 3 the upper hook bracket 10 of the present invention comprises a main body 21 and a tyre engaging hook portion 22. The hook has an upper tyre engaging surface 23 and immediately below it a lower hook surface 24. Thus the hook insofar as its tyre support function is concerned is exactly the same as the prior art hook shown in Figure 2.

The main body 21 however also has a longitudinally extending pressurised gas port 25 and adjacent to the hook mounting member 26 a gas input port 27.

The main gas port 25 connects to a gas holding chamber 28 from which three separate gas ports 29, 30 and 31 extend. Each of the gas ports 29, 30 and 31 pass through the lower surface 24 of the hook bracket at spaced-apart positions. The third gas port 31 has formed over its output a lip 32 formed so that the output of the port comprises a passage 33 extending parallel to the lower surface 24. This passage 33 points towards the point of the tyre engaging hook 22.

Three or more of the above hooks are used to support the upper bead of the tyre in the conventional manner, but in this case pressurised gas which may be nitrogen or air is supplied in the direction of A shown in Figure 3 to the port 27 and thence flows out of the three ports 29, 30 and 33. The result is a flow of pressurised gas across the lower surface 24 of the hook. Thus when the interior of the tyre is sprayed with tyre paint whilst the tyre is hung on the hooks the flow of pressurised gas prevents tyre spray settling on the hook in any substantial quantity and thus prevents the formation of drops of tyre paint which may fall on to the opposite bead of the tyre.

Accordingly the invention prevents build up of troublesome tyre paint on the hooks improving tyre paint quality and thus the finished quality of the tyres on curing and also preventing the build up of paint on the hooks leading to the need to clean the hooks.

Claims (10)

1. An upper hook bracket for a tyre spray painting machine having an upper tyre retaining surface and a lower surface adjacent thereto characterised by at least at the lower surface means to direct pressurised gas along said lower surface so as to prevent the collection of tyre paint on said surface.

2. A hook bracket according to claim 1 characterised in that the means comprises a hole through said lower surface connected through a passage in a main body to a source of pressurised gas.

3. A hook bracket according to claim 2 characterised by more than one said hole in the lower surface.

4. A hook bracket according to claim 2 or 3 characterised in that the hole has an aperture adapted to direct the pressurised gas along the lower surface.

5. A hook bracket according to claim 4 characterised in that the aperture is a hole provided at an acute angle of less than 100 to the lower surface.

6. A hook . bracket according to claim 4 characterised in that the aperture has a metal lip to direct the pressurised gas along the lower surface.

7. A method of painting a tyre comprising supporting said tyre on at least three hook brackets according to any of claims 1 to 6, and supplying pressurised gas to the lower hook surface to blow tyre paint from said lower surface and thus prevent paint build up.

8. A method according to claim 7 characterised in that the pressurised gas is directed along the lower surface of the hook bracket.

9. An upper hook bracket constructed and arranged substantially as described herein and illustrated in Figures 1 and 3 of the accompanying drawings.

10. A method of painting a tyre substantially as disclosed herein.