GB2173995A - Vehicle window wiper arrangement - Google Patents

Abstract

A vehicle window wiper arrangement comprises a surround adapted to receive a vehicle window (16), said surround incorporating a guide track along which runs at least one drive member, a wiper blade (12, 14) attached to the drive member and a mechanism for reciprocating the drive member to and fro along the track. In one embodiment, a channel-shaped strip 28 of magnetisable material having an energising coil surrounding a central part thereof is arranged within the surround, and a moulded component 34 provided with a permanent magnet 34 is arranged to be reciprocated to and fro adjacent strip 28 within the surround, when the coil is energised, thereby driving the wiper blade 12, 14. In another embodiment, component 34 carrying the wiper blade is reciprocated to and fro within the surround by a DC motor M which drives a friction wheel R, the supply of electrical current to the motor being via strips S and contacts C. <IMAGE>

Description

SPECIFICATION Vehicle window wiper arrangement This invention relates to a vehicle window wi per arrangement.

The term "vehicle window wiper" as used herein refers more especially but not exclusivelytothe windscreens of road vehicles and the rear windows of motor cars, but notwithstanding this also extends to the windscreens of other vehicles such as railway traction units and boats, and to othervehicle windows where wipers may be employed, such as the windows of vehicle headlamps.

Vehicle windscreens and rear windows typically comprise laminated sheet glass sealed by a surround into a window aperture in the pressed vehicle body.

The wiper unit is separately manufactured and includes a drive unit fitted to the vehicle body adjacent the window. A wiper blade drive arm pivotally attached to the drive unit is spring loaded towards the window and carries a wiper blade which is driven when the drive unit is operative to sweep a part ofthe window area, usually with oscillating arcuate motion.

It is an object of this invention to provide an improved window wiper arrangement for a vehicle, with the aims of sweeping an increased area of the window, improving vision through the windscreen and improving aerodynamic flow over the window to which the wiper or wipers is or are fitted.

According to the invention, there is provided a vehicle window wiper arrangementwhich comprises a surround adapted to receive a vehicle window, said surround incorporating, at least along the lower or the upper longitudinal edge thereof, a guide track along which can run at least one drive member, a wiper blade attached to the drive memberto bear against the window with its length extending generally at right angles to the length ofthewindow, and driving meansforcausingthedrivememberto reciprocate in a linear manneralong atleasta part of the length of the window.

In a first possible arrangement the wiper blade(s) is driven electromagnetically, i.e the guide track and drive member movable thereon constitute a miniature linear motor.

For this purpose, the track may be constituted by a strip of electromagnetic material and the drive memberconsitituted by a permanent magnet. The magnetic field generated by the track is polarised first one way and then the other, switching being effected so that the magnet, and thus the wiper blade attached thereto, is linearly reciprocated along the length of the window.

In one possible construction ofthefirst arrangement the electromagnetic track is of U crosssection, and the permanent magnet runs in the field between the limbs of the U-section. Afield coil may be situated around or adjacent the crnss-limb ofthe U-section. The permanent magnet is preferably incorporated in a component which not only carries the wiper blade, but is positively retained and guided by the window surround incorporating the track. This surround may be of moulded plastics material forming a housing for the electromagnetic track.

In a second preferred arrangement, the drive member comprises a D#C Motor and the necessary driving means for causing the drive member to reciprocate, comprises a wheel rotated in use by the output shaft of the motorto meke frictional driving engagement with the guide track.

Such an arrangement is to some extent "overengineered" but could well constitute a potentially successful and easily constructed screen wiper. The DCmotorcould beforexampleaseries-wound motorofwell known kind and proven reliability, with the necessary electrical contact between the motor and the source of direct current being provided by feeding the current to strip contacts running along the path of movementofthe motor in much the same conceptual manner as the electrical current is fed to the driving motors of model trains or model racing cars in another field of invention.

The electrical means causing the D C motorto reverse the direction of rotation of the wheel at each extreme of the motortravel may be selected from known alternatives without inventive thought by the intended skilled addressee of this specification.

In both the first and second arrangements, the wiper blade(s) is preferably driven both top and bottom, i.e. both the top longitudinal edge and the bottom longitudinal edge of the surround incorporate tracks for drive members respectively attached to the top and bottom of the wiper blade, the upper and lower said drive members being driven in synchronism.

In the case of a ca r wi ndscreen, fo r exa m ple, a single blade may be reciprocableacrosstheentire width of the window, but preferably two blades, for preference both driven top and bottom synchronously, may cover a part ofthe width of the window. In the "parked" or rest condition, the or each blade will be disposed against a side edge ofthe window.Assuming the use of two blades, for example, the rest condition will be with the respective blades at the opposite sides ofthe window, but it is not essential forthe two blades to operate absolutely symmetrically with respect to position across the two parts ofthe window. An offset allowing a small overlap at the centre ofthe windscreen is obtainable via the mounting means by which the blades are attached to the respective drive members.

Alternatively, by using separate tracks in the surround at opposite halves of the window, the starting strokes of the respective blades may offset in time so that the two blades simultaneously move in the same direction across the window at any given instant.

In the case where the drive is electromagnetic, the direction in which any blade is moving acrossthe window depends not only on the direction of polarisation of the track or tracks, but also on the direction of magnetisation of the permanent magnet which constitutes the drive member. It is thus readily possible to achieve any preferred combination of relative movements for the two blades. The energising field for the electromagnetictrack(s) may conveniently be derived from the alternator ofthe vehicle. However, switching control is preferably effected via a small microprocessor which is programmed to be responsive to various inputs derived from one or more control switches, which can if desired be of a conventional kind, thereby to obtain any speed of movement of the blades within a given range and/or any period of interruption between successive sweeps.

A preferred wiper blade for use in both the first and second arrangement in accordance with the invention is in the nature of a combined wash roller and squeegee element, with profile maintained by internal tension.

Window sash facilities can be provided in the usual manner, but preferably the jet unit(s) will also be incorporated in the window surround, in accordance with the general aim of the invention to provide a window unit which incorporates wiper blade facilities as an integral part of the unit.

The above-described arrangements in accordance with the invention have the advantages of: (a) enabling substantially the entire area of the window to be swept by the wiper blades; (b) enabling the rest condition to be with the blades at the sides of the window, thus improving aerodynamic flow across the window, especially in the case of a front windscreen from bonnet to roof line; (c) enabling the possibility of a more rounded shape to the door line thereby to achieve better all round vision; (d) enabling greater versatility in the speed and timing of the wiper blade movements.

Two practical wiper blade arrangements in accordance with the invention are exemplified in the accompanying drawings, in which: Figure 1 is a diagrammatic front view of a first car window unit; Figure 2 is a diagrammatic transverse crosssection through an edge of the window surround of Figure 1; Figure 3 is a block circuit diagram of the first arrangement; and Figure 4 is a diagrammatic transverse cross section through an edge of the window surround of a second car window unit.

Referring to Figure 1, there is shown a first window unit 10 in this instance intended to form the rear window of a car. Wiper blade facilities are incorporated as an integral part of the unit.

The wiper blade member comprises a combined textured wash roller 12 and squeegee blade 14, internally tensioned to conform to the profile of window glass 16, and linearly movable from side to side across the window as indicated by the arrow and line 18. The drive is provided by means incorporated in the upper and lower edges of the window surround 20, which is diagrammatically illustrated in the transverse cross-section of Figure 2, wherein for reasons of clarity, the respective parts are not necessarily drawn to corresponding scales.

As can be seen from Figure 2, which can be considered to represent a cross-section through either the top longitudinal edge or the bottom longitudinal edge of the surround, a plastics moulded outer part 22 is sealed to the window glass 16 at 24 and is adapted to seal to the vehicle body, at the edge of the window aperture therein, at 26. The outer part 22 encloses an elongate strip or track 28 of magnetisable material, which is U-shaped in cross-section. An energising coil 30 surrounds the cross limb of the U-section.

Between the two arms of the strip 28 is movable a permanent magnet 32, incorporated in a moulded component 34 guided for linear movement by the outer part 22.

Attached to the component 34 is the wiper blade member 12,14.

Referring to Figure 3, the coil 30 is energised from the alternator 36 of the vehicle via a switch controller 38, the switching action of which is governed by a programmed miniature microprocessor 40. The microprocessor carries out its programme responsively to inputs from dashboard or steering column controls 42, thereby to operate the switch controller 38 so that the coil 30 is energised in either of two polarities or is deenergised, in accordance with the programme and the inputs to the microprocessor.

The magnetisable strip 28 generates a reversible magnetic field in accordance with the programme of energisation of the coil 30, thereby to cause the permanent magnet 32, and thus the wiper blade member 12,14, linearly to reciprocate across the window. The top and bottom of the wiper blade member are driven in synchronism, and the rest condition is at one side edge of the window. The wiper blade can be driven within a range at any chosen speed or any period of interruption between successive strokes, in accordance with the inputs from the controls 42.

The arrangement described with reference to Figures 1,2 and 3 of the drawings can be modified in various ways within the scope of the invention hereinbefore defined. For example, the window unit can incorporate two wiper blades driven from a single electromagnetic track or split electromagnetic tracks. The or each blade may in some circumstances be driven only from the top or from the bottom. Finally, the construction and form of the linear motor utilised to impart the drive can also be varied to suit requirements and the type of vehicle to which the invention is applied.

A second car window unit is shown in Figure 4.

This is similar to the first window unit except that the drive components 28,30 and 32 are replaced by new drive components C, M. R ad S.

A series-wound D C Motor is fixed to a moulded component 34 which engages respective top and bottom part-round grooved tracks in a plastics moulded outer part 22 so that the component 34 is guided for linear movement (in a direction transverse to the plane of the drawing) by the outer part 22.

Attached to the component 34 is a wiper blade member 12, 14whose characteristics are the same and have already been described above with reference to the first window unit. Also described above with particular reference to Figure 1 of the drawings is the way in which, in use, component 34 carries blade 12, 14 back and forth across screen 16. The movement of component 34 and motor M of the second embodiment is identical.

The means driving component 34 in this particular embodiment comprise a wheel or roller R fixed to the output shaft of motor M and rotating when the output shaft rotates. Roller R is in frictional driving engagement with one inside wall of part 22. The necessary supply of electrical current is fed to spaced-apart strips S which run the length of intended travel of motor M, component 34 and wiper blade 12, 14 and against which contacts C are respectively spring-loaded from within locations on motor M.

As motor M moves, contacts C move with it and slide along and over strips S to maintain a continuing supply of electrical current to rotate roller R. At its extremes of travel across the screen, motor M reverses the direction of rotation of roller R to travel back across the screen. The circuitry necessary to effect such reversal need not be described and is not illustrated.

Claims (18)

1. A vehicle window wiper arrangement which comprises a surround adapted to receive a vehicle window, said surround incorporating, at least along the lower or the upper longitudinal edge thereof, a guide track along which can run at least one drive member, a wiper blade attached to the drive member to bear against the window with its length extending generally at right angles to the length of the window, and driving means for causing the drive member to reciprocate in a linear manner along at least a part of the length of the window.

2. An arrangement according to Claim 1, in which the guide track and drive member movable thereon constitute a miniature linear motor.

3. An arrangement according to Claim 2, in which the track is constituted by a strip of electromagnetic material and the drive member constituted by a permanent magnet.

4. An arrangement according to Claim 3, in which the electromagnetic track is of U cross-section, and the permanent magnet runs in the field between the limbs of the U-section.

5. An arrangement according to Claim 4, in which a field coil is situated around or adjacent the cross limb of the U-section.

6. An arrangement according to any one of Claims 3,4 or 5, in which the permanent magnet is incorporated in a component which not only carries the wiper blade, but is positively retained and guided by the window surround incorporating the track.

7. An arrangement according to any one of Claims 3 to 6, in which the energising field for the electromagnetic track(s) is derived from the alternator of the vehicle.

8. An arrangement according to Claim 1, in which the-drive member comprises a D C Motor and the driving means comprises a wheel rotated in use by the output shaft of the motor to make frictional driving engagement with the guide track.

9. An arrangement according to Claim 8, in which the D C Motor is a series-wound motor and the electrical contact between the motor and the source of direct current being provided by feeding the current to strip contacts running along the path of movement of the motor.

10. An arrangement according to any one of the preceding Claims, in which the wiper blade is driven both top and bottom, i.e. both the top longitudinal edge and the bottom longitudinal edge of the surround incorporates tracks for drive members respectively attached to the top and bottom of the wiper blade, the upper and lower said drive members being driven in synchronism.

11. An arrangement according to any one of the preceding Claims, in which two wiper blades are included, each reciprocable across part of the width of the window.

12. An arrangement according to Claim 11, in which the mounting means by which the blades are attached to the respective drive members are offset to allow a small overlap at the centre of the window.

13. An arrangement according to Claim 11 when dependant upon any one of Claims 3 to 7, in which separately energisable tracks are included in the surround at opposite halves of the window, with the starting strokes of the respective blades offset in time so that the two blades simultaneously move in the same direction across the window at any given instant.

14. An arrangement according to any one of the preceding claims, in which switching control is effected via a small microprocessor which is programmed to be responsive to various inputs derived from one or more control switches, thereby to obtain any speed of movement of the blades within a given range and/or any period of interruption between successive sweeps.

15. An arrangement according to any one of the preceding claims, in which the wiper blade is in the nature of a combined wash roller and squeegee element, with profile maintained by internal tension.

196. An arrangement according to any one of the preceding claims, in which jet unit of window wash facilities are incorporated in the window surround.

17. A vehicle window wiper arrangement arranged substantially as herein described, with reference to, and as illustrated in, Figures 1 to 3 of the accompanying drawings.

18. A vehicle window wiper arrangement arranged substantially as herein described with reference to, and as illustrated in, Figures 1 to 3 when modified in accordance with Figure 4 of the accompanying drawings.