GB2191390A

GB2191390A - Wiper blade rubber

Info

Publication number: GB2191390A
Application number: GB08706723A
Authority: GB
Inventors: Charles Henry Frimley
Original assignee: Trico Ltd
Current assignee: Trico Ltd
Priority date: 1986-03-20
Filing date: 1987-03-20
Publication date: 1987-12-16
Also published as: GB8706723D0; GB8606905D0

Abstract

A windscreen wiper blade rubber comprises hollow body (2) provided with a chamber (9) for receiving a vertebra, and two lip portions (11 and 12), the ends (14) of which engage the windscreen. The lip portions may be spaced from each other or joined together mechanically or adhesively. The channel (29) may be used for supplying wash water to the channel between the lip portions via apertures in the vertebra. Alternatively, where there is no channel (29), chamber (9) may be enlarged so as to carry water as well as house the vertebra. The blade rubber may be made by extrusion or moulding. <IMAGE>

Description

SPECIFICATION Blade rubber for the blade of a windscreen wiper This invention relates to a blade rubber for the blade of a windscreen wiper.

By the term "blade rubber" used throughout this specification is to be understood that part of a windscreen wiper blade which comprises a longitudinal element of the blade which, in use, is pressed against the windscreen to provide the actual wipe. It should not be understood that this element is made out of rubber as it may be made from synthetic rubber or a similar plastics material.

If, in present day production, it is desired to use a single vertebra or backing strip with the blade rubber, it is usually necessary to insert the vertebra in a channel in the upper part of the blade rubber or to mould the vertebra into the material of the blade rubber as it is being formed. The first method has the disadvantage that it is possible to pull the vertebra out of the blade rubber if, for example, the blade rubber is stuck to the windscreen in icy conditions, because of the necessity of there being an at least partly open slot in the top of the blade rubber. The second method has the disadvantage that, with normal moulding techniques, it is difficult to provide a satisfactory mould or, with the use of an extrusion, it is difficult to prevent the blade rubber from taking on a permanent curvature.

The present invention seeks to provide a blade rubber for the blade of a windscreen wiper which obviates or substantially reduces some or all of the above mentioned disadvantages.

According to the invention, a blade rubber for the blade of a windscreen wiper comprises an elongate element of rubber or like material including a longitudinally extending hollow body to provide a vertebra chamber for receiving a vertebra, the hollow body being closed in at least three directions, a first direction away from the windscreen with which the blade is intended to be used and second and third directions at right angles to the first direction, and two lip portions, the ends of which are intended to engage the windscreen, which portions extend from the hollow body in a fourth direction which is opposite to the first direction.

The lip portions may be spaced from each other so that two individual lips are formed or they may be connected together such that both lip portions together form a single lip.

The blade rubber may comprise two or more parts hinged together by elements of material of reduced thickness. The blade rubber may be either extruded or moulded.

The hollow body of the blade rubber may be four sided in cross section, being closed on three sides and being provided with an opening in the fourth side, the lip portions extending from the fourth side on opposite sides of the opening.

The lip portions may extend from adjacent the edges of the opening or may be spaced apart by a distance greater than the width of the opening.

The hollow body may be thickened, for example below the vertebra chamber and grooves may be formed therein to provide for attachment of claws on the yokes or levers of the blade harness.

The invention will now be described in greater detail, by way of example, with reference to the drawings in which: Figure 1 is a transverse cross sectional view of a first form of blade rubber in accordance with the invention; Figure 2 is a sectional view of the blade rubber shown in Fig. 1 in the form in which it can be moulded or extruded; Figure 3 is a figure similar to Fig. 1 but showing a second form of blade rubber produced from the moulding or extrusion of Fig.

2; Figure 4 is a view similar to Fig. 2, but showing a different form of moulding or extrusion; Figure 5 is a view similar to Fig. 1, but showing a section of a blade rubber produced from the moulding or extrusion of Fig. 4; Figure 6 is a view similar to Fig. 1, but showing a form of blade rubber having two lips with a maximum spacing, and Figure 7 and 8 are similar views showing two other forms of blade rubber in accordance with the invention.

Referring firstly to Fig. 1, there is shown a transverse section through a blade rubber 1.

This blade rubber comprises a hollow body 2 which is closed on three sides 3, 4 and 5 but has a small opening 6 on the fourth side 7.

As can be seen, the main chamber 9 of this hollow body 2 is of rectangular section and forms a vertebra chamber intended to receive a single element vertebra (not shown) of metal or plastics material which is intended to extend substantially the whole length of the blade rubber. In some cases, it may extend beyond the end of the blade rubber if this is required for fixing purposes. The assembly of the vertebra into the hollow body will be described hereafter in connection with Fig. 2.

Extending from the fourth side 7 of the hollow body 2, on either side of the opening 6, are two lip portions 11 and 12. As shown in the drawing, these lip portions have a free end 14 which is intended to engage the windscreen to be wiped. The lip portions 11 and 12 are widened out upwardly to form two stop elements 15 for control of the movement of the lips. Adjacent to these stop elements 15 are neck portions 16 of reduced width which allow the lips to flex within the limits allowed by the stop elements 15. A wider portion 17 is provided above each neck portion 16, forming part of the hollow body.

Longitudinal grooves 19 are formed in this portion 17 to receive the claws (not shown) of the supporting harness of the windscreen wiper blade.

Fig. 2 is a sectional view of a moulding or extrusion from which the blade rubber of Fig.

1 is produced. As will be seen, the mould or extrusion 20 is in two parts 21 and 22 which are mirror images of each other and are connected together by a bridge portion 23 which can also be seen in Fig. 1. It will also be noted that the cross section has a substantially flat lower edge 24 which, if the method used is extrusion, enables the extrusion to be readily supported as it emerges from the extrusion die so that the resulting blade rubber does not have an unwanted permanent curvature. The free ends 14 of the lip portions 11 and 12 are situated at the outside edges of the cross section so that they can be readily trimmed if necessary. In a moulding operation, this would be the area in which flash would be formed and any flash could be easily trimmed off.

From the completed moulding or an extrusion cut to length, it is a simple matter to assemble the vertebra in the blade rubber. Because of the very thin bridge portion 23, the two parts of the blade rubber are relatively flexible with respect to each other and the blade rubber can thus be folded together about the ''hinge'' 23 so as to enfold the vertebra in the chamber 9. Depending on the desired fixing arrangements, the vertebra may be shorter than, of the same length as or longer than the blade rubber. If necessary, an adhesive may be applied to the vertebra so as to retain it safely in the chamber 9. There is no possibility of pulling the vertebra out of the blade rubber since there is no opening in the top of the blade, and to have any significant success", it would be necessary to break the bridge portion 23.

Once the blade rubber has been enfolded into the form shown in Fig. 1, it can be inserted in the claws of the blade harness in the usual way. Any desired method of retaining the blade rubber in the harness and retaining the vertebra longitudinally in the blade rubber can be used. In the extruded form, end clips of various kinds can be used while, in the moulded form, retaining devices may be produced by suitable moulding of the blade rubber material.

With the blade rubber as so far described, it will be appreciated that the finished blade will have a blade rubber with two adjacent but spaced lips. While this has a number of advantages in practice, it may still be desired to produce a blade rubber with a single lip. This can be achieved using the same moulding or extrusion as shown in Fig. 2.

Such a blade rubber is illustrated in Fig. 3.

In this case, the bridge portion 23, instead of being used as a bridge, is pushed up into a small projection 25 at the top, allowing the two parts of the moulding or extrusion 20 to approach each other. The two parts can then be joined together mechanically or by the use of adhesives so that they are joined along the centre line of the finished blade rubber. In this way, the two free ends 14 of the lip portions 11 and 12 are connected together to form a single lip 27.

Fig. 4 shows another cross section of a moulding or extrusion which can be used to form a blade rubber in accordance with the invention. A blade rubber formed therefrom is shown in Fig. 5.

From Fig. 5 it will be seen that the form of blade rubber produced is almost identical to that shown in Fig. 1. The only difference lies in the omission of the slot 29 which extends upwardly from the chamber 9 to the bridge portion 23.

The moulding or extrusion 30 shown in Fig.

4 is formed of three parts 31, 32 and 33 connected by two hinge parts 35 and 36 situated at the upper corners of the chamber 9.

These are not in the form of a bridge, as is the part 23 in the first embodiment, but are more in the nature of hinges. By adjustment of the relative lengths of the part 32 and of the side of the moulding indicated at 38, the spacing of the lip portions 11 and 12 can be set from the zero position as shown in Fig. 3 to a spacing which is greater than that shown in Fig. 5.

It will of course be understood that, from the point of view of extrusion, the extrusion 30 does not have as flat an underneath surface 39 as the surface 24 of the extrusion 20.

Fig. 6 shows an embodiment in which the spacing of the lips 14 is maximised. This is achieved by reversing the positions of the lip portions 11 and 12 and forming them on the other ends of the enlarged portion 17 instead of adjacent to the slot 6. The blade rubber of this enmbodiment can be produced from a moulding or extrusion similar to that shown in Fig. 2, but suitably modified.

Figs. 7 and 8 show two further embodiments of the invention which are not produced from the split mouldings of Figs. 2 and 4.

Fig. 7 is an embodiment which is basically similar to Fig. 5. It differs in the shape of the hollow body 41 which is rectangular instead of trapezoidal as shown in Fig. 5. It is intended that this embodiment should be extruded since its shape is not really suitable for other types of moulding. Otherwise it has the same form as previous embodimemnts.

Fig. 8 is a version of the embodiment of Fig. 7 in which the neck 16 is omitted. This can be effective where the material used for producing the blade rubber is such as to allow greater resilience of movement of the lips 14 of the blade rubber.

It will be appreciated that the above described embodiments may be varied or modified without departing from the scope of the invention. For example, the various features of the various embodiments may be combined together in any suitable way. In one such arrangement, the neck 16 could be omitted from the embodiments of Figs. 1 to 5 where suitable material is used for the blade rubber.

The increased spacing of the lip portions 11 and 12 as shown in Fig. 6 could also be applied to the embodiments of Figs. 5, 7 and 8.

The blade rubber of the above described embodiments lends itself to the provision of "in-blade" washing facilities. To this end, the channel 29 above the chamber 9 could be used for carrying a supply of washing water, the water then passing through apertures formed in the vertebra and down the channel formed between the two lip portions 11 and 12.

In embodiments which do not have the channel 29, the chamber 9 could be enlarged, above or below the vertebra, to carry the water. In a further alternative, a two piece vertebra could be used, a space being left between the two parts for the water flow.

Claims

1. A blade rubber for the blade of a windscreen wiper comprising an elongate element of rubber or like material including a longitudinally extending hollow body providing a vertebra chamber for receiving a vertebra, the hollow body being closed in at least three directions, a first direction away from the windscreen with which the blade is intended to be used and second and third directions at right angles to the first direction, and two lip portions, the ends of which are intended to engage the windscreen, which portions extend from the hollow body in a fourth direction which is opposite to the first direction.

2. A blade rubber as claimed in claim 1, wherein the lip portions are spaced from each other so that two individual lips are formed.

3. A blade rubber as claimed in claim 1, wherein the lips are connected together such that both lip portions together form a single lip.

4. A blade rubber as claimed in claim 1, 2 or 3, wherein the blade rubber comprises two or more parts hinged together by elements of material of reduced thickness.

5. A blade rubber as claimed in any one of claims 1 to 4, wherein the blade rubber is extruded.

6. A blade rubber as claimed in any one of claims 1 to 4, wherein the blade rubber is moulded.

7. A blade rubber as claimed in any one of claims 1 to 6, wherein the hollow body of the blade rubber is four sided in cross section, being closed on three sides and being provided with an opening in the fourth side, the lip portions extending from the fourth side on opposite sides of the opening.

8. A blade rubber as claimed in claim 7, wherein the lip portions extend from adjacent the edges of the opening.

9. A blade rubber as claimed in claim 7, wherein the lip portions are spaced apart by a distance greater than the width of the opening.

10. A blade rubber as claimed in any one of claims 1 to 9, wherein the hollow body is thickened in specific areas and grooves are formed in this thickened part to provide for attachment of claws on the yokes or levers of the blade harness.

11. A blade rubber as claimed in claim 10, wherein the hollow body is thickened below the vertebra chamber.

12. A blade rubber for the blade of a windscreen wiper substantially as described herein with reference to the drawings.