IMPROVEMENTS IN OR RELATING TO WINDSCREEN WIPERS

Abstract: A windscreen wiper includes a flexible wiping member and two bearing members on each side of the wiping member, the bearing members being brushes or scrapers and having a depth relative to the wiping element which is such that, in use, with the wiping member deflected its free end rests under the free end of the bearing member.

Description: TITLE: IMPROVEMENTS IN OR RELATING TO WINDSCREEN WIPERS The present invention concerns an improved windscreen wiper. Over recent years a need to provide a windscreen wiper which is more efficient than existing wipers and can cope not only with rain-water but also with debris, for example mud and squashed insects has been identified and several improved arrangements have been proposed some incorporating, in addition to the normal wiper blade elements such as scrapers and brushes. Our U.K. Patent No. 1356910 discloses one form of improved wiper which has been proved in practice to be successful especially on flat wind screens. Problems have arisen, however, in use of prior compound wipers on curved windscreens and especially on those cars where the radius of curvature of the curve of the windscreen is pronounced. Several attempts have been made to overcome this problem some with greater degrees of success than others but it would appear that those which have been most successful have resulted in a complicated and con sequently expensive wiper design including a number of components. It is an obJect of the present invention to obviate or mitigate these disadvantages. According to the present invention there is provided a windscreen wiper including a flexible wiping member extending longitudinally of the wiper and two bearing members arranged on each side of the wiping member. Preferably the bearing members are brushes but alternatively they may be plastics material scrapers. Preferably the wiping member is fixed to a body member capable of being mounted in a wiper backing member or spine intended for use with standard wiper blades. The body member may also mount the bearing members. It is preferable that the length of the wiping member projecting out of the body member is greater than the length of the bearing members projecting out of the body member. It is further preferable that the length of the wiping member is such that when, in use, it is deflected relative to the body member, its free end rests below the free end of a bearing member. The body member may include passages therethrough to supply cleaning fluid to the windscreen. Said passages may be arranged to project washing fluid onto the windscreen either externally of the cavity defined by the bearing members the body member and the windscreen or alternatively into the cavity. Preferably valve means are provided for the passages such that in operation cleaning fluid is supplied to the area of the windscreen in front of the wiper. Preferably the brushes of the bearing members are provided with plastics material bristles mounted in a plastics material spine having a width greater than the width of the assembly of bristles. Preferably the wiping member and body member are formed integrally by extrusion from a synthetic rubber material. Preferably channels of substantially Tshaped cross section are formed in the body member on either side of the wiping member to accommodate the bearing members. Alternatively the wiping member may be formed as a separate unit mounted in a body member manufactured from a more rigid plastics material. In this instance the wiping member may be provided with an upper flange adapted from mounting in a T-shaped channel in the body member. It is possible that the bristles of the brush member may be mounted directly in the plastics body member. It will be realised that uith a more rigid body member, for example the plastics body member described in the immediately preceding paragraphs the need for a standard windscreen wiper spine may not be eviden and the wiper may be mounted directly to the wiper assembly carrier. Embodiments of the present invention will now be described by way of example only with reference to the accompanying drawing in uhich: Fig. 1 shows a cross section through a first form of wiper element Figw 2 shows a cross section through a second form of wiper element Fig. 3 shows the wiper element of Fig. 2 during operation Fig. 4 shows a further form of wiper element and Fig. 5 shows a further form of wiper element. Fig. 1 illustrates a cross-sectio#nal elevation of a wiper including a wiping member and two brush members. A body member 10 has a wiping member or blade 12 formed integrally therewith and projecting from its base. On the side of the body member remote from the blade 12 there is provided a longitudinally extending ridge 14 having grooves 16 formed in its opposed upstanding faces, the grooves 16 being intended to accommodate the flexible steel backing member or spine 18 of a windscreen wiper. On either sid of the centre line of the body member 10 there are formed two channels 20 of T-shaped cross-section. Longitudinally extending bearing members in the form of brushes 22 are mounted in the channels, the brushes 2 having bristles 24 fixed to a rectangular crosssection backing member or spine 26. A modified wiper is illustrated in Figs. 2 and 3, Fiqure 3 showing also the ouLer surface U of a windscreen, A number of the components of the wiper shown in Figs. 2 and 3 are common to that shown in Fig. 9 and have been given the same reference numerals: they will not be described again in detail. In this embodiment, however, the longitudinal ridge 14 is modified. It is provided along each of its sides with a flap 3n spaced above the upper surface 22 of the body member 10. The width of the ridge 14 intermediate the flap 30 and said upper surface 32 is reduced compared to the width at the spine 18 and a cleaning fluid passage 34 of substantially circular cross section extends through this ridge at the reduced width portion. At intervals along the length of the element transverse passages 36 provide communication for cleaning fluid between the passage 34 and the exterior of the element. It will be realised that if the fluid is supplied under sufficient pressure it will be projected onto the windscreen and Figure 3 illustrates how the feed of fluid to the windscreen is controlled such that it is supplied, in use, to only the leading side of thr wiper. In Figure 3 it can be seen that in operetion as the wiper moves across the surface of the winscreen ' in the direction of arrow Q not only is the wiping blade 12 deformed such that it trails but also the body member 10 pivots in a clock-wise direction. This pivoting movement causes the passages 36 on the trailing side of the wiper to tend to close and if the flaps 30 are designed such that their length is adequate they abut the upper surface 32 to further cut off the supply of cleaning fluid. Figure 3 illustrates an important feature of the invention which is the length of the blade 12 projecting beyond the under-face of the body 10. This is carefully chosen such that it is greater than the amount of projection of the bristles 24 but is only so great that when the wiper is deformed in use, as illustrated in Figure 3, the free end 13 of the blade is located below the ends of the bristles 24 of the trailing brush. It has been found that this gives rise to a particularly efficient arrangement and considerably reduces the drag on the wiping element caused by the contact of the blade 12 with the windscreen surface M. At the commencement of a wiping stroke, at one point, the blade occupies a position substantially similar to that shown in Figure 2 and as thp wiping arm moves the wiping element across the windscreen in the direction oF arrow A the blade 12 deforms. During this initial movement the body member occupies a position similar to that shown in Figure 2 as the drag exerted on the blade is considerable, the body 10 is caused to tilt relative to the ridge 14 until the lower ends oF the bristles 24 of the leading brush contact the surface IJ of the windscreen. As well as acting as a scrubbin: member, in this condition, they act as a bearing member for the wiper and the co-efficient of friction between the ends of the bristles and the windscreen is much reduced compared with that between the blade alone and the windscreen so that the drag is reduced without decreasing the wiping efficiency of the blade 12 which is held in contact with the windscreen surface U not only by virtue of its own resilience and the resilience of the body member 10 but also under the downward force exerted by the bristles 2b of the trailing brush. At the end of a traverse of the wiper the motion is reversed and the blade flips over" to occupy a position with its free end under the ends of the bristles of the other brush. In Figure 4 there is shown a further modified wiper and, again, components similar to the components illustrated in the Figure 1 embodiment have been given the same reference numerals and will not be described in detail. In this arrangement cleaning fluid is supplied to a cavity defined in operation by the bristles of the leading brush 2t the body member 10 the blade 19 and tho windscreen surface W. Passage means 39 between the cleaning fluid conduit 34 and this cavity C are provided through the body member 10. Downwardly projecting auxiliary members 40 are provided at the lateral extremities of the bo#y member 10 to contain the cleaning fluid in the area of operation. It has been found that to increase the flexibility of the wiping element in the longitudinal direction such that it can readily curve to the curved profile of the windscreen the brushes should be located as close to the spine 18 as possible and an attempt to provide this facility is illustrated in Figure 5. In this embodiment the blade 12 is not formed integrally with the body member but has an upper flange 42 mounted in a substantially T-shaped channel formed in a relatively rigid plastics material body member 44, the depth of which is less than its width. In view of the relatively rigid nature of the body member 44 it is possible to directly mount the bristles 24 therein. When considering the operation of the wiper of Figure 2 it is apparent that a resilient twisting moment tending to restore the wiping element to its undeformed condition is necessary for the effective operation of the wiper. It will be realised that as the body of the wiper shown in Figure 5 is relatively rigid such that resilience is not built into the element and it is necessary, therefore, that the mounting of the element of Figure 5 to the wiper arm is such that rotational resilience is provided. Various other modifications can be made within the scope of the invention, for example the bearing brushes may be replaced by other boaring members, such as nylon members adapted to scrape rather than scrub debris off the windscreen in the path of the wiper blade. In this modification the nylon members are remounted in the manner similar to the brushes but, of course? further alternative mounting methods could be employed. Additionally, as illustrated in Figure 5, it is not necessary for the blade 12 to be formed as an integral part of the body member: it could be formed as a replaceable member perhaps being manufactured from a different material from the body member. Another modification can be achieved by varying the position of the brushes but it has to be realised that there is a distinct and important relationship between the length of the brushes, their position relative to the blade and the length of the blade so that the effects shown in Figure 3 or an effect resembling this are obtained during a wiping operation. In a still further modification the spine 18 could be moulded integrally into the ridge #0. Various modified methods of supplying cleaning fluid to the windscreen could be employed and in fact it is not necessary to provide a central conduit 36 to supply the cleaning fluid. This could be provided by a separate external tube mounted alongside th rd or in any other convenient location. In addition, if the cleaning fluid distributing means illustrated in Figure 2 are em.)#oyed, that is with a valving arrange ment to prevent the fint of cleaning fluid to the trailing edge of the blade, then any suitable method of valve to control the cleaning fluid may be used. It should be realised that whereas in the preceding description the method of manufacturing the body member and wiping member has been by extrusion, they can be moulded. Similarly the material employed need not be synthetic rubber but can be natural rubber or any suitable plastics material. Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that flu Applicant claims protection in respect of any patentable feature or combination offeatures hereinbefore referred to whether or not particular emphasis has been placed thereon.

Claims: CLAIMS 1. R windscreen wiper characterised that it includes a flexible wiping member (12) extending longitudinally of the wiper and two bearing members (22) arranged on each side of the wiping member (12). 2. A windscreen wiper as claimed in claim 1 characterised thai the bearing members arc brushes (22). 3.. A windscreen wiper as claimed in any one of claims 1 to 3 characterised in that the wiping member (12) is fixed to a body member (10) capable of being mounted in a wiper backing member or. spine (18) intcnded for use with standard wiper blades. 4. r, windscreen wiper as claimed in claim 3 charact- erised in that the body member (10) mounts the bearinn members (22). 5. A windscreen wiper as claimed in dim 4 or claim 5 characterised in that the length of the wiping member (19) projection out of the body member (10) is so much greaser than the length of th beering members (22) projecting out of the body member such thz:: hen, in usc, it is deflected relative to the body member (in), its free end rests below the free end of a bearing member (22). 6. A windscreen wiper ns claimed in na one of claims 4 to i characterised in that the body member (10) includes passages (34,3G,33) therethrough to supply cleaning fluid to the windscreen, said passages (34,36,38) being arranged to project washing fluid onto the windscreen either externally of the cavity defined by the bearing members (22) the body member (10) and the windscreen or alternatively into the cavity, valve means being provided for the passages (34,36,38) such that in operation cleaning fluid is supplied to the area of the windscreen in front of the wiper. 7. A windscreen wiper as claimed in any one of claims 2 to 6 characterised in that the brushes (22) are provided with plastics material bristles (24) mounted in a plastics material spine (26) having a width greater than the width of the assembly of bristles and in that channels (20) of substantially T-shaped cross section are formed in the body member (10) on either side of the wiping member (12) to accommodate the spines (26). 8. A windscreen wiper as claimed in any one of claims 3 to 7 characterised in that the wiping member (12) and body member (10) are formed integrally by extrusion from rubber material. 9. A windscreen wiper as claimed in any one of claims 3 to 7 characterised in that the wiping member (12) is formed as a separate unit mounted in a body member (10) manufactured from a more rigid plastics material and is provided with an upper flange (42) adapted from mounting in a T-shaped channel in the body member (44). 10. A windscreen wiper an claimed in claim 9 characterised in that the bristles (24) of the brush member (22) are mounted directly in the plastics body member (44).

Inventors: KNIBBS, GEORGE SAFEWYPE INTERNATIONAL LTD. UNIT 58
Applicants: SAFEWYPE INTERNATIONAL LIMITED
Application year: 1983
Main classification: B60S1
IPC codes: B60S1