Vertebra arrangement for a windscreen wiper blade rubber and a windscreen wiper blade arrangement incorporating such a vertebra arrangement

Abstract: A vertebra arrangement for a windscreen wiper blade rubber comprises a pair of flat strips (1,3) for location in longitudinal grooves in the longitudinal sides of the blade rubber, each strip (1,3) being provided with an open slot (7) facing sideways of the strip (1,3) and extending outside the line of the strip at a position to captivate a claw on the blade harness when the strip is located in the blade rubber and at least one strip being being bent or formed round at one end (9) away from the side of the strip containing the claw captivating slot (7) so as, in use, to penetrate the material of the blade rubber.

Description: This invention relates to a vertebra arrangement of a windscreen wiper blade rubber and to a windscreen wiper blade arrangement incorporating such a vertebra arrangement. Modern windscreen wiper blades are usually formed with a harness comprising a plurality of yokes, the ends of which, adjacent to the blade rubber, are provided with claws which hold the blade rubber in place while allowing relative longitudinal movement between the rubber and the claws or all but one of the claws so that the blade, together with the rubber can flex to follow the curve of the windscreen to which it is to be applied. The "rubber" is usally made from rubber, either natural or synthetic and, due to the characteristics of the material, it is not sufficiently rigid in a transverse direction to maintain a proper wipe characteristic. Thus, rigidity is imparted to the rubber by means of a stiffening member(s) or vertebra(e) which extend longitudinally for the length of the rubber. One type of vertebra which is known is the so called "twin rail" vertebra. This consists of a pair of flat metal or other strips which seat in longitudinal grooves in the blade rubber. The problem then remains of maintaining the vertebra in the blade rubber and also of preventing the blade rubber from sliding out of the claws of the blade harness. In the past, moulded rubbers were used and the requisite location was provided by appropriate moulding of the rubbers. Thus, for example, the slots carrying the vertebra were closed at both ends so as to prevent the vertebra from sliding out longitudinally. The assembly of rubber and vertebra was then retained in the harness by the provision of a pocket in the rubber in to which one of the claws of the harness penetrate and are held thereby. While this has proved to be satisfactory in practice, with the development of technology to reduce production costs, there has been a tendency to change from the relatively expensive moulded rubbers to extruded rubbers. With extruded rubbers, it is not, of course, possible to provide closed end slots so that other means of securing the vertebra in the blade rubber has been found to be necessary. Various proposals have been made for this purpose. For example, it is possible to place an end clip on one or both ends of the rubber and to secure this by providing it with slots by means of which it can be held by the harness claw. However, this solution requires one or two additional parts per blade and thus goes a long way towards taking up the cost saving made by the use of an extruded rubber. One proposal which has been made is to provide a cut out on the inside of the vertebra strip and forming the ends of the cut out portion with inwardly extending teeth which penetrate the blade rubber adjacent to the claw position (FR-A-2502086). However, such an arrangement makes for complicated manufacture and provides a weakness in the vertebra strip. The present invention seeks to provide a vertebra arrangement for a blade rubber and a construction of windscreen wiper blade arrangement in which some or all of the above disadvantages are reduced or substantially obviated. According to a first aspect of the invention, a vertebra arrangement for a windscreen wiper blade rubber comprises a pair of flat strips for location in longitudinal grooves in the longitudinal sides of the blade rubber, each strip being provided with an open slot facing sideways of the strip and extending outside the line of the strip at a position to receive a claw on the blade harness when the strip is located in the blade rubber and at least one strip having a tooth portion bent or formed to the side of the strip away from the claw receiving slot so as, in use, to penetrate the material of the blade rubber, in which the said tooth portion is at the end of said strip and is bent or formed round. Preferably only one of the strips is provided with the bent or formed end and in this case, the strip with the bent or formed end will usually be longer than the other strip. The bent or formed end may be of reduced dimensions to aid in penetrating the material of the rubber, which rubber may be preformed with a hole to receive the bent or formed end. The bent or formed end may be pointed to assist in penetration of the material of the rubber, and in this event, the preformed hole in the rubber may be omitted. Where the claw receiving slots are formed towards one end of the strips so as to receive the end claw of the blade harness, the bent or formed end may be provided either at this end or at the opposite end. Where both strips are provided with bent or formed ends, these may suitably be arranged at opposite ends of the respective strips. According to a second aspect of the invention, there is provided a windscreen wiper blade arrangement with a vertebra arrangement as defined above, the windscreen wiper arrangement comprising a harness including a main yoke or lever, pivotal means for attaching the main yoke or lever to a windscreen wiper arm and at least one secondary yoke or lever pivotally connected in the middle region thereof to one end of the main yoke or lever, the free ends of the yokes or levers being provided with the said claws, the said blade rubber being carried by the claws of the yokes or levers. The invention will now be described in greater detail, by way of example, with reference to the drawings, in which:- Figure 1 is a plan view of a pair of strips forming a vertebra arrangementin accordance with a first embodiment of the invention; Figure 2 is a fragmentary perspective view of a windscreen wiper blade incorporating the vertebra arrangement of figure 1; Figure 3 is a fragmentary perspective view of the part of the blade shown in figure 2 but taken from the opposite direction; Figures 4, 5 and 6 are views similar to figure one showing different embodiments of the vertebra arramgement, and Figure 7 is an enlarged view of one end of a strip showing a special formation of the bent or formed end. Referring firstly to figure 1, there is shown a vertebra arrangement comprising a pair of flat strips 1 and 3, suitably produced from flattened wire. The major part of each strip 1 and 3 are identical, the two strips being bowed apart at 5 and having outwardly facing slots 7 therein for the purpose of receiving the claw of a blade harness as will be described in relation to figures 2 and 3. The strip 1 is longer than the strip 3 and has its outer end 9 bent or formed round at 11 to provide a portion 15 extending substantially at right angles to the rest of the strip 1. This portion 15 is intended to penetrate the material of the blade rubber and secure the strip 1 against longitudinal movement relative to the blade rubber. It will be noted that the portion 15 is only half the width of the rest of the strip 1 and extends from the inner edge thereof. Figures 2 and 3 show the vertebra arrangement in use. In these figures are shown fragments of a blade harness comprising a subsidiary yoke or lever 21 whose free end 23 terminates in a claw 25. The blade rubber carried by the blade harness is shown at 27. As can be seen, the two strips 1 and 3 are located in longitudinal grooves 29 in the blade rubber 27. They are retained in the harness by the fact that the claw 25 of the subsidiary yoke or lever 21 is captivted in the slot 7. The strip 1 is retained in the rubber 27 by the portion 15 extending through an aperture or hole 31 in the blade rubber. This aperture 31 may be preformed or may be produced simply by forcing the portion 15 through the material of the blade rubber 27. In greater detail, strip 1 is securely located and retained longitudinally in the groove 29 of the blade rubber 27 by virtue of the penetration of the blade rubber 27 by the portion 15 of the strip 1 and transversely by the claws 25 of the blade harness. Because of the receivion of the claw 25 in the slot 7, the strip 1 is also prevented from longitudinal movement with respect to the harness. The remaining claws (not shown) of the harness are not received, allowing the rest of the blade rubber sufficient longitudinal play to be able to follow the curve of a windscreen to which it is applied. The second strip 3 is located in the rubber through the claw 25 which is coupled to the positively located first strip 1. Figure 4 shows a variation of the vertebra arrangement shown in figure 1 in that the portion 15 is pointed at 33. This pointing of the portion 15 assists the penetration of the material of the blade rubber 27, particularly if its aperture 31 is not preformed. Figure 5 shows a version of the vertebra arrangement in which the portion 15 is not provided at the same end of the strip 1 as the slots 7 but serves the same purpose. It may well be that this version is more easily fabricated accurately. Figure 6 shows a vertebra arrangement similar to that shown in figure 1 except that the portion 15 of the strip 1 extends from its outside edge instead of its inside edge. This could reduce the risk of cracking of the material of the strip 1 when bending or forming it. Figure 7 shows how the portion 15 of the strip 1 can be formed with a twist as well as a bend to provide a larger surface area in the longitudinal direction of the blade rubber 27. To provide a maximum surface, the portion 15 is not of reduced width compared to the remainder of the strip 1 except in the area of the bend 11. It will be appreciated that various modifications may be made to the above described embodiments without departing from the scope of the invention. For example, portions 15 could be provided on both strips 1 and 3, one strip having the portion 15 at one end and the other strip having a portion 15 at the other end. If desired, with this construction, the slot 7 could in both cases be positioned near to the portion 15 so that each strip would receive adifferent claw and there would be no direct connection between the strips. Both strips could then be identical, doing away with the necessity of fabricating two different strips and, since the portins 15 can extend around the end of the rubber instead of through it, the need to pierce a hole in the rubber. From the foregoing, it will be seen that the invention provides a vertebra arrangement which, in its described embodiments enables an extruded blade rubber to be secured to a blade harness without the use of additional parts or the need to close in the claws after assembly.

Claims: A vertebra arrangement of a windscreen wiper blade rubber (27) comprising a pair of flat strips (1,3) for location in longitudinal grooves (29) in the longitudinal sides of the blade rubber (27), each strip (1,3) being provided with an open slot (7) facing sideways of the strip (1,3) and extending outside the line of the strip (1,3) at a position to receive a claw (25) on the blade harness (21,23) when the strip (1,3) is located in the blade rubber (27) and at least one strip (1,3) having a tooth portion (15) bent or formed to the side of the strip (1,3) away from the claw receiving slot (7) so as, in use, to penetrate the material of the blade rubber (27), characterised in that the said tooth portion (15) is at the end of said strip and is formed or bent round. An arrangement as claimed in claim 1, characterised in that only one of the strips (1,3) is provided with the bent or formed end (15). An arrangement as claimed in claim 2, characterised in that the strip (1,3) with the bent or formed end (15) is longer than the other strip (1,3). An arrangement as claimed in any preceding claim, characterised in that the rubber (27) is preformed with a hole (31) to receive the bent or formed end (15) of the strip (1,3). An arrangement as claimed in any preceding claim, characterised in that the bent or formed end (15) of the strip (1,3) is pointed (33) to assist in penetration of the material of the rubber (27). An arrangement as claimed in any preceding claim, characterised in that the claw receiving slots (7) are formed towards one end of the strips (1,3) so as to receive the end claw (25) of the blade harness. An arrangement as claimed in claim 6, characterised in that the bent or formed end (15) of the strip (1,3) is provided at the end adjacent to the claw receiving slot (7). An arrangement as claimed in claim 6, characterised in that the bent or formed end (15) of the strip (1,3) is provided at the end away from the claw receiving slot (7). An arrangement as claimed in any preceding claim, characterised in that both strips (1,3) are provided with bent or formed ends (15) at opposite ends of the respective strips (1,3). A windscreen wiper blade arrangement with a vertebra arrangement as claimed in any preceding claim, characterised in that it comprises a harness including a main yoke or lever, pivotal means for attaching the main yoke or lever to a windscreen wiper arm and at least one secondary yoke or lever (21) pivotally connected in the middle region thereof to one end of the main yoke or lever, the free ends (23) of the yokes or levers (21) being provided with the said claws (25), the said blade rubber (27) being carried by the claws (25) of the yokes or levers (21).

Inventors: MOWER PETER, MOWER, PETER
Applicants: TRICO FOLBERTH LTD, TRICO-FOLBERTH LIMITED
Application year: 1990
Main classification: B60S1
IPC codes: B60S1