GB2085713A - Windscreen-Wiper/drive assemblies - Google Patents

Abstract

A windscreen-wiper/drive assembly comprises a wiper arm 7 mounted on a slide block 10 which is slidable laterally of the windscreen 4, a guide positioned adjacent the bottom edge of the screen 4, and power-operated driving means for reciprocating the block laterally of the windscreen. The latter may comprise an endless belt 1 looped around pulleys 2, 3, and connected to block 10 by a cranked coupling arm 11, pulley 3 being driven by motor 5. Alternatively, the block may be driven by passage of air or other fluid into a plastics tube which is nipped between rollers, as shown in Fig. 2. <IMAGE>

Description

SPECIFICATION Windscreen-wiper/drive assemblies This invention relates to windscreen wipers, and has for its principal object to provide an improved windscreen-wiper/drive assembly. To this end a windscreen-wiper/drive assembly according to the invention has a wiper blade which sweeps laterally across the screen with a linear motion.

A further specific object is to provide such an assembly which can readily be adapted to curved windscreens, and which can use conventional replacement wiper arm assemblies and wiper blades.

According to a particular aspect of the invention a windscreen-wiper/drive assembly comprises a wiper arm with a mounting which is guided so as to be slidable laterally of the screen, and a drive therefor comprising an endless belt (or chain) looped around a pair of spaced pulleys (or sprockets) at least one of which is driven with a rotary motion, the wiper arm mounting being coupled to the drive belt in such manner that the arm sweeps laterally to-and-fro across the screen.

One or both of the pulleys may be continuously driven by a windscreen-wiper motor. The arm mounting is preferably a guided slide block member, the guide for which may be curved to conform to the shape of the screen, and the two pulleys are preferably mounted just below the screen and respectively positioned adjacent the bottom corners thereof. The slide axis of the arm mounting is desirably so offset out of the plane of the belt and pulleys that the slide block member can move at least partially past or beyond the pulleys at each end of its travel. This allows the pulleys to be positioned within the overall width of the screen, and facilitates the coupling of the arm mounting to the endless belt so as to allow continuous uni-directional driving of the pulleys to produce the lateral to-and-from movement of the arm and mounting.

The blade mounting is preferably connected to the belt through a cranked coupling arm, and this arm may pivot on a blade mounting spindle projecting from the slide block member.

The invention will now be further described with reference to the accompanying drawing which illustrates, in Fig. 1 diagrammatically and by way of example, a preferred embodiment of the invention.

In the drawing a wiper blade of the assembly illustrated is shown in two alternative positions of its travel.

The windscreen-wiper/drive assembly illustrated includes a drive comprising an endless belt 1 looped around two spaced pulleys 2 and 3 respectively mounted below the windscreen 4 adjacent and slightly inwardly of the bottom corners thereof. The screen is of conventional shape, and thus may have a pronounced lateral curvature as is commonly the case with the windscreens of passenger vehicles, for example, and a driving motor 5 is directly coupled to the pulley 3 which it drives with a continuous unidirectional rotary motion.

A windscreen-wiper blade assembly 6 is of conventional form, having a wiper arm 7 with a splined female mounting at its lower end 7a on a supporting spindle 8 forming part of a mounting for the arm.

The arm 7 carries a spring-mounted wiper blade 9 so that the latter is pressed against the screen 4 and can flex and move, relatively to the wiper arm 7, in order to conform closely to the contour of the screen 4 as it sweeps across the latter. The mounting for the arm 7 also includes a slide block member 10 in which the spindle 8 is non-rotatably secured so as to project for mounting of the arm 7.

The slide block 10, which thus non-rotatably carries the wiper arm 7, is guided for reciprocatory movement laterally of the windscreen 4 and along a slide axis A-A. It is so guided by a slideway (not shown) which is curved to match the lateral curvature of the screen 4, and the axis A-A is offset from the plane of the belt and pulleys so that the slide block 10 can pass in front of the pulleys 2 and 3, respectively, at both ends of its travel along the slideway, as shown in position 'Bin respect of pulley 2 in the drawing. A stepped lower arm 1 1a of a coupling member 11, which is mounted for free pivotal movement on the spindle 8 between the block 10 and the arm 7, is connected at 12 to the belt 1.Thus movement of the belt carries with it the coupling member 11, slide block member 10 and wiper arm assembly 6, so that the blade 9 sweeps laterally across the screen.

The offset of the axis A-A and the shape of the coupling member 11 are matched so that, as shown at position 'A' in the drawing, the coupling arm 1 la and the wiper arm 7 are generally aligned and substantially at right angles to the belt run as the blade sweeps across the screen in one direction with the connection 12 on the lower run la of the belt as shown. The cranked shape of the coupling member 11 and the dimensions of the block 10 enable the connection 12 to track around the pulleys 2 and 3 so that it follows the upper and lower belt runs on alternate wiper movements.

Thus at each end limit of the linear reciprocatory movement the block 10 passes in front of the corresponding pulley 2 or 3, as shown at position 'B', while the connection 12 tracks around the periphery of that pulley. The pivotal mounting of the coupling member 11 on the slide block 10 thus accommodates, at each end of the lateral movement of the block 10, the movement of the connection 12 around the corresponding pulley on to the other belt run along which it moves during the next sweep traverse of the arm 6 across the screen 4. This allows the pulleys to be positioned, as shown, within the overall width of the screen 4 immediately below the latter, with the blade 8 sweeping close up to the side edges of the screen 4.

The usual parking control is incorporated in the driver-switched control circuit of the motor 5. Thus, when the driver of the vehicle to which the assembly The drawing(s) originally filed was/were informal and the print here reproduced is taken from a later filed formal copy.

is fitted switchesoffthewindscreenwiper,themotor is automatically controlled to move the wiper arm assembly 6 to a parking position at one side edge of the screen before the motor stops.

An alternative embodiment ofthe invention will now be described further, by way of example, with reference to Figs. 2 and 3 of the accompanying drawings: In the embodiment of Figs. 2 and 3 similar reference numerals have been used to designate similar parts to those of Fig. 1.

In Figs. 2 and 3 a flexible plastics tubing, 1, is provided which is located at either end by two tubes, 3 and 4, which are sealed inside the tubing, and held in place by two brackets, 5 and 6. Through either of these tubes air or other suitable fluid can be passed into the plastic tubing independently from each other. In the present example the fluid is air.

Intermediate the ends of the tubing are two rollers, 7 and 8, which are "nipped" together, one on one side of the plastics tubing, 1, the other on the opposite of the tubing, providing a seal at their closest point. Hence air from one side cannot pass beyond the rollers to the other side. These rollers, 7 and 8, are connected to the slider block, 9, which in turn has the wiper unit mounted directly upon it. This whole unit can then slide the length ofthe windscreen with the rollers continuously pinching the plastics tubing, 1, as it does. Two stitches, 10 and 11, are located at either extremity of the slideway.

When air or a liquid is passed down one of the tubes, 3 or4, the plastics tube will become full and pressurised with air/liquid, but only up to the position of the two rollers which are sealing and tubing.

Thus, pressure builds up on the side that the fluid is applied and acts upon the two rollers, causing them to move away from the applied pressure, to move the rollers and hence, the slider/wiper unit linearly across the screen.

When the rollers I slider / wiper unit traverses to the opposite end of the track, it contacts a switch, 10 or 11, which automatically switches the supply of air or fluid to act on the other side of the plastic tubing and hence the other side of the rollers. The rollers / slider/ wiper unit moves in the opposite direction until it reaches the other end of the slideway, where it will again contact a switch, putting the air/fluid supply in at the other end of the tubing, 1, to move the rollers / slider/ wiper unit in the other direction.

In another example, a wiper may alternatively be propelled using a unit which has one roller only, which presses against tubing containing air or other fluid. A backing plate is used as the opposite sealing member instead of the second roller arrangement.

Claims (15)

1. A windscreen-wiper/drive assembly comprising a wiper arm with a mounting which is slidable laterally of the screen, guide means for said mount ing positioned adjacent an edge of the screen, and power-operated driving means connected to said mounting and operative to reciprocate the latter laterally of the screen so that the wiper arm sweeps laterally to-and-fro across the screen.

2. An assembly according to claim 1, wherein said arm mounting is a slide block member.

3. An assembly according to claim 2, wherein said guide means comprise a guide for said slide block member curved to conform to the shape of the screen.

4. An assembly according to any one of the preceding claims, wherein said driving means comprise an endless belt (or chain) looped around a pair of spaced pulleys (or sprockets), said wiper arm mounting being coupled to the drive belt.

5. An assembly according to claim 4, wherein the slide axis of the mounting member is offset out of the plane of the belt and pulleys, and the slide block member moves at least partially past or beyond the pulleys at each end of its travel.

6. An assembly according to claim 4 or claim 5, wherein one or both of said pulleys is or are in use continuously and uni-directionally driven by a windscreen-wiper motor of the driving means.

7. An assembly according to any one of claims 4 to 6, wherein said two pulleys are respectively mounted just below the screen and respectively positioned adjacent the bottom corners thereof.

8. An assembly according to claims 5 and 7, wherein the pulleys are positioned within the overall width of the screen.

9. An assembly according to any one of claims 2 to 8, wherein the blade mounting is coupled to the belt through a cranked coupling arm.

10. An assembly according to claim 9, wherein said coupling arm pivots on a blade mounting spindle which projects from the slide block member.

11. An assembly according to any one of claims 1 to 3, wherein said driving means are fluid-pressure operated and provide a comprise a tube subject to fluid pressure and nipped to the point of closure between two rollers connected to the slide block.

12. An assembly according to claim 11, wherein said tube can be supplied with pressure fluid from either end to provide a reversible bi-directional drive.

13. An assembly according to claim 12, wherein the respective limit switches are positioned for operation at the ends of the travel of the wiper arm mounting, and operation of either limit switch serves to change over the end of the tube to which the pressure fluid is at the time supplied.

14. A windscreen-wiper/drive assembly constructed and arranged substantially as herein particu larly described with reference to Figure 1 of the accompanying drawings.

15. A windscreen-wiper/drive assembly constructed and arranged substantially as herein particularly described with reference to Figures 2 and 3 of the accompanying drawings.