Method of modifying a windscreen wiper drive mechanism

Abstract

Aspects of the present invention relate to a method of modifying a windscreen wiper drive mechanism (10). The method comprises: a) cutting a static support member (12) along a first cut line (34) to s

Description

TECHNICAL FIELD The present disclosure relates to a method of modifying a windscreen wiper drive mechanism and to a jig for use in such a method. BACKGROUND Standard windscreen wiper drive mechanisms are often configured for use on a particular type of windscreen, which means they cannot easily be used on windscreens of different shape or size. Embodiments of the present invention aim to adapt an existing windscreen wiper drive mechanism for use on alternative windscreen types. SUMMARY OF THE INVENTION Aspects and embodiments of the invention provide a method of modifying a windscreen wiper drive mechanism and a jig to facilitate the method, a vehicle as claimed in the appended claims. According to an aspect of the present invention there is provided a method of modifying a windscreen wiper drive mechanism, the windscreen wiper drive mechanism having first and second wiper drive spindles rotatably connected to first and second ends of a static support member, and a drive linkage configured to transmit rotary movement of a drive motor to the first and second wiper drive spindles to drive reciprocating movement of the first and second wiper drive spindles about first and second axes which diverge in a longitudinal direction by a divergence angle; the method comprising the steps of: a) cutting the static support member along a first cut line to separate a first end portion thereof having the first wiper drive spindle attached thereto; b) cutting the static support member along a second cut line orientated at an angle to the first cut line to remove a section of the static support member between the first cut line and the second cut line; c) reattaching the first end portion having the first wiper drive spindle attached thereto to the static support member at the second cut line so that the first wiper drive spindle is in a modified position, in which the first axis has been changed from a first orientation to a second orientation, which differs from the first orientation, to reduce the divergence angle between the first and second axes. The second cut line may be at an angle relative to the first cut line of at least 5 degrees, preferably from 7.5 to 11 degrees, so that the divergence angle is reduced by at least 5 degrees, preferably from 7.5 to 11 degrees. The first and second cut lines may be spaced apart by a distance of at least 50 mm, optionally in the range of 50 mm to 90 mm, optionally in the range of 60mm to 75mm, to shorten the static support member and thereby reduce the distance between the first and second wiper drive spindles. The drive linkage may comprise a motor arm, first and second links, and first and second cam arms. Each of the first and second links may comprise a first end rotatably coupled to the motor arm and a second end rotatably coupled to a first end of the respective cam arm. Each of the first and second cam arms may comprise a second end non-rotatably coupled to the respective wiper drive spindle. Thereby, rotation of the motor arm causes reciprocating transverse movement of the links, which causes reciprocating rotation of the cam arms and wiper drive spindles about respective sweep angles. The first and second cam arms may each have a length of at least 50 mm. In that case the method may comprise reducing the length of the first and / or second cam arm by at least 4 mm. Optionally, the length of the first cam arm may be reduced by approximately 5 mm and length of the second cam arm may be reduced by approximately 10 mm. The first link and second links may each have a length of at least 250 mm. The method may further comprise reducing the length of the first and / or second link. The reduction may be at least 50mm, or by approximately 68 mm. In another aspect, the present invention provides a jig for use in the method of any preceding claim, wherein the jig comprises: a first formation configured to locate the first wiper drive spindle with the first axis in said first orientation prior to cutting the static support member; first and second cutting indicators which define guides for the first and second cut lines respectively; and a second formation configured to locate the separated first end portion with the first wiper drive spindle in said modified position in order to reattach the first end portion to the static support member at the second cut line with the first axis in said second orientation. Thus by modifying a windscreen wiper drive mechanism employing the method described herein, the mechanism designed for one vehicle, for example one having a relatively wide screen that is curved dictating an angle between the axes of the respective wiper drive spindles, can be employed in another vehicle having a flatter windscreen dictating a lesser angle of inclination between the axes of the respective wiper drive spindles and optionally also in the case of a narrower windscreen dictating a lesser separation between the axes of the respective wiper drive spindles. BRIEF DESCRIPTION OF THE DRAWINGS One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a front perspective view of a windscreen wiper drive mechanism coupled to wiper arms; Figure 2 is a rear view of the windscreen wiper drive mechanism of Figure 1; Figure 3 is a schematic flow chart of a method according to the invention; Figures 4 and 5 are plan views of a jig for use in the method of Figure 3 with original and adapted wiper drive mechanisms shown positioned within the jig; and Figures 6a and 6b show a change in divergence angle between first and second axes of a wiper drive mechanism when modified by the method of Figure 3 using the jig of Figures 4 and 5. DETAILED DESCRIPTION Referring firstly to Figures 1 and 2, a windscreen wiper drive mechanism is indicated at 10. The windscreen wiper drive mechanism 10 has a static support member 12 which is fixed in place relative to a vehicle chassis or bodywork via a mounting arrangement 13. The windscreen wiper drive mechanism 10 also has first and second wiper drive spindles 14A, 14B rotatably connected to first and second ends 16A, 16B of the static support member 12. The windscreen wiper drive mechanism 10 has a drive linkage 18 configured to transmit rotary movement of a drive motor 20 to the first and second wiper drive spindles 14A, 14B to drive reciprocating movement of the first and second wiper drive spindles 14A, 14B about first and second axes A1, A2. In this way, when the first and second wiper drive spindles 14A, 14B are fixed to respective wiper arms 100A, 100B (as illustrated in Figure 1), rotary movement of the drive motor 20 results in reciprocating movement of the wiper arms 100A, 100B, which in turn leads to reciprocating movement of wiper blades 102A, 102B attached to the wiper arms 100A, 100B over a windscreen surface (not shown) in order to clear the windscreen surface. The drive linkage 18 includes a motor arm 21, first and second links 22A, 22B, and first and second cam arms 24A, 24B. The first link 22A has a first end 26A rotatably coupled to the motor arm 21, and a second end 28A rotatably coupled to a first end 30A of the first cam arm 24A. The first cam arm 24A also has a second end 32A non-rotatably coupled to the first wiper drive spindle 14A. In this way, rotation of the motor arm 21 causes reciprocating transverse movement of the first link 22A, which causes reciprocating rotation of the first cam arm 24A and the first wiper drive spindle 14A about a sweep angle around the first axis A1. Similarly, the second link 22B has a first end 26B rotatably coupled to the motor arm 21, and a second end 28B rotatably coupled to a first end 30B of the second cam arm 24B. The second cam arm 24B also has a second end 32B non-rotatably coupled to the second wiper drive spindle 14B. In this way, rotation of the motor arm 21 causes reciprocating transverse movement of the second link 22B, which causes reciprocating rotation of the second cam arm 24B and the second wiper drive spindle 14B about a sweep angle around the second axis A2. Windscreen wiper drive mechanisms 10 of the type illustrated in Figures 1 and 2 may be configured so that the first and second axes A1, A2 of the first and second wiper drive spindles 14A, 14B diverge in a longitudinal direction by a divergence angle 6 (e.g. as best illustrated in Figure 6a). This facilitates use of the windscreen wiper drive mechanism 10 on a curved screen in which different portions of the screen which are passed over by the wiper blades 102A, 102B are not parallel to each other. It will therefore be understood that the optimal amount of divergence between the first and second axes A1, A2 varies depending on the curvature of the windscreen, with a comparatively flat screen requiring less or no divergence between the first and second axes A1, A2 and a comparatively more curved screen requiring greater divergence between the first and second axes A1, A2. Referring now to Figure 3, a method of modifying a windscreen wiper drive mechanism 10 of the kind described above is indicated schematically as a flow chart. The method involves the following steps. At step S10, the static support member 12 is cut along a first cut line 34 (as illustrated on Figures 4 and 5). This allows a first end portion 15 of the static support member 12 having the first wiper drive spindle 14A attached thereto to be separated, at step S20, from the remainder of the static support member 12. At step S30, the static support member 12 is cut along a second cut line 36 oriented at an angle a to the first cut line 34 (as illustrated on Figures 4 and 5) to remove a section of the static support member 12 between the first cut line 34 and the second cut line 36. At step S40, the first end portion 15 having the first wiper drive spindle 14A attached thereto is reattached by, for example, welding to the static support member 12 at the second cut line 36 so that the first wiper drive spindle 14A is in a modified position, in which the first axis A1 ’ has been changed from a first orientation 01 to a second orientation 02, which differs from the first orientation 01, to reduce the divergence angle 0 between the first and second axes A1 A2 (as illustrated by the dashed lines on Figure 5). It will be understood that reducing the divergence angle 0 may result in: arrangements where the first and second axes A1’, A2 still diverge, but to a lesser extent than before; arrangements where the first and second axes A1 A2 are parallel; or converging arrangements (in which the divergence angle 0 between the first and second axes A1 ’, A2 is reduced to below zero). Step S40 may involve welding or fastening the first end portion 15 to the remainder of the static support member 12 (e.g. the portion of the static support member 12 extending from the second cut line 36 to the second end 16B of the static support member 12). In some embodiments, the second cut line 36 is at an angle a relative to the first cut line 34 of at least 5 degrees, preferably from 7.5 to 11 degrees, so that the divergence angle 0 is reduced by at least 5 degrees, preferably from 7.5 to 11 degrees. For example, in the illustrated embodiment, the second cut line 36 is at an angle a of approximately 9 degrees relative to the first cut line 34. Such an angle a between the first and second cut lines 34, 36 (and corresponding reduction in the divergence angle 0) is suitable for adapting a typical wiper drive mechanism configured for use with a curved windscreen to be suitable for use with a flat windscreen. In some embodiments, the first and second cut lines 34, 36 are spaced apart by a distance of at least 50 mm, optionally in the range of 50 mm to 90 mm, optionally in the range of 60mm to 75mm. For example, in the illustrated embodiment, the first and second cut lines are spaced apart by a distance of 68mm. This shortens the static support member 12 and thereby reduces the transverse distance between the first and second wiper drive spindles 14A, 14B. This allows a wiper drive mechanism originally designed for use on a comparatively larger windscreen to be modified for use on a comparatively smaller windscreen and / or with shorter wiper arms. In some embodiments, the method includes the optional step S50 of reducing a length of the first and / or second cam arms 24A, 24B. In some embodiments, the first and second cam arms 24A, 24B each have a length of at least 50 mm, and step S50 involves reducing the length of the first and / or second cam arm 24A, 24B by at least 4 mm. For example, in the illustrated embodiment, the first cam arm 24A has an original length of approximately 68 mm with 5mm being removed to provide a reduced length of approximately 63mm, and the second cam arm 24B has an original length of approximately 77.5 mm with 10mm being removed to provide a reduced length of approximately 67.5 mm. It will be understood that reducing the length of the first and / or second cam arms 24A, 24B results in a greater sweep angle for a given transverse movement of the respective link 22A, 22B, which may be useful when adapting a windscreen wiper drive mechanism for a windscreen of different shape which requires greater sweep angles and / or requires the use of shorter wiper arms. In some embodiments, step S50 involves replacing the first and / or second cam arms 24A, 24B with a shorter cam arm. In other embodiments, step S50 involves trimming a length of the first and / or second cam arm 24A, 24B. In some embodiments, the method includes the optional step S60 of reducing a length of the first and / or second link 22A, 22B. In some embodiments, the first and second links 22A, 22B each have a length of at least 250 mm, and step S60 involves reducing the length of the first and / or second link 22A, 22B by at least 50 mm. For example, in the illustrated embodiment, the first link 22A has an original length of approximately 270 mm with 68 mm being removed to provide a reduced length of approximately 202 mm. This is in line with a corresponding reduction in the length of the static support member 12 (i.e. by way of a distance of approximately 68 mm between the first and second cut lines 34, 36). In some embodiments, step S60 involves replacing the first and / or second links 22A, 22B with shorter links. In other embodiments, step S60 involves trimming a length of the first and / or second links 22A, 22B. While the method steps S10 to S60 are depicted in a particular order in Figure 3, it will be understood that the method steps may be carried out in any suitable order. For example, step S60 may occur before step S50, step S50 and / or step S60 may be omitted, etc. Referring now to Figures 4 and 5, a jig for use in the method of Figure 3 is indicated at 200. The jig 200 has a central support 201 for receiving the static support member 12 to support the wiper drive mechanism 10 in position on the jig 200. The jig 200 also has a first formation 202 configured to locate the first end portion 15 prior to cutting the static support member 12 (as illustrated by the dashed lines in Figure 4). The jig 200 also has first and second cutting indicators 204, 206 which define guides for the first and second cut lines 34, 36 respectively. The jig 200 also has a second formation 208 configured to locate the separated first end portion 15 with the first wiper drive spindle 14A in said modified position in order to reattach the first end portion 15 to the static support member 12 at the second cut line 36 (as illustrated by the dashed lines in Figure 5) so that the first axis of the AT of the first wiper drive spindle 14A is in the second orientation 02. It will be understood that, since the first and second cutting indicators 204, 206 define guides for the first and second cut lines 34, 36 (which are arranged at an angle relative to each other), the first and second cutting indicators 204, 206 are arranged at an angle a relative to each other (e.g. an angle a of approximately 9 degrees in the illustrated embodiment). Similarly, it will be understood that in embodiments where the first and second cut lines 34, 36 are spaced apart (e.g. by a distance of 68mm in the illustrated embodiment), the first and second cutting indicators 204, 206 are spaced apart by a corresponding distance. In the illustrated embodiment, the jig 200 also has third and fourth cutting indicators 210, 212 for guiding cut lines on the first link 22A in order to trim a length of the first link 22A. For example, the first link 22A, is cut along third and fourth cut lines at the third and fourth cutting indicators 210, 212 and the portion between the third and fourth cut lines is removed in order to reduce the length of the first link 22A. In the illustrated embodiment, the jig 200 is substantially symmetrical. In other words, a first set of first and second formations 202, 208 and cutting indicators 204, 206, 210, 212 is provided on a first side 214A of the jig 200, and a second set of first and second formations 202, 208 and cutting indicators 204, 206, 210, 212 is provided on a second side 214B of the jig 200. In this way, either or both ends 16A, 16B of the static support member 12 can be cut in order change the orientation of the corresponding axis A1, A2 of the respective wiper drive spindle 14A, 14B to reduce the divergence angle 0. This may also be useful for allowing a single jig 200 to be used for modifying left-hand drive vehicle and right-hand drive vehicle versions of a wiper drive mechanism. Figures 6a and 6b illustrate the change in divergence angle 0 between the first and second axes A1, A2 when the method of Figure 3 is carried out using the jig of Figures 4 and 5. When the first axis A1 is in the first orientation 01, the divergence angle 0 between the first and second axes A1, A2 is approximately 10 degrees, as depicted in Figure 6a. However, after the method of Figure 3 has been carried out and the first axis AT is in the second orientation 02, the first and second axes AT, A2 are approximately parallel, as depicted in Figure 6b. In other words, the divergence angle 0 between the first and second axes A1 A2 has been reduced to approximately 0 degrees. It will be appreciated that various changes and modifications can be made to the present disclosed examples without departing from the scope of the present application. Whilst 5 endeavouring in the foregoing specification to draw attention to those features believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and / or shown in the drawings whether or not particular emphasis has been placed thereon. 10 25 03 25

Claims

1. A method of modifying a windscreen wiper drive mechanism, the windscreen wiper drive mechanism having first and second wiper drive spindles rotatably connected to first and 5 second ends of a static support member, and a drive linkage configured to transmit rotary movement of a drive motor to the first and second wiper drive spindles to drive reciprocating movement of the first and second wiper drive spindles about first and second axes which diverge in a longitudinal direction by a divergence angle; the method comprising the steps of:a) cutting the static support member along a first cut line to separate a first end portion 10 thereof having the first wiper drive spindle attached thereto;b) cutting the static support member along a second cut line orientated at an angle to the first cut line to remove a section of the static support member between the first cut line and the second cut line;c) reattaching the first end portion having the first wiper drive spindle attached thereto 15 to the static support member at the second cut line so that the first wiper drive spindleis in a modified position, in which the first axis has been changed from a first orientation to a second orientation, which differs from the first orientation, to reduce the divergence angle between the first and second axes.

2. The method of claim 1, wherein the second cut line is at an angle relative to the first 20 cut line of at least 5 degrees.

3. The method of claim 2, wherein the second cut line is at an angle relative to the first cut line from 7.5 to 11 degrees.

4. The method of claim 3, wherein the second cut line is at the angle relative to the cut line from 7.5 to 11 degrees, so that the divergence angle is reduced by at least 5 degrees.25 5. The method of any of claims 1-3, wherein the first and second cut lines are spacedapart by a distance of at least 50 mm to shorten the static support member and thereby reduce the distance between the first and second wiper drive spindles.

6. The method of claim 5, wherein the first and second cut lines are spaced apart by a distance in the range of 50mm to 90mm.30 7. The method of claim 6, wherein the first and second cut lines are spaced apart by adistance in the range of 60mm to 75mm.25 03 258. The method of any preceding claim, wherein the drive linkage comprises a motor arm, first and second links, and first and second cam arms, wherein each of the first and second links comprises a first end rotatably coupled to the motor arm and a second end rotatably coupled to a first end of the respective cam arm, and wherein each of the first and second 5 cam arms comprise a second end non-rotatably coupled to the respective wiper drive spindle, such that rotation of the motor arm causes reciprocating transverse movement of the links, which causes reciprocating rotation of the cam arms and wiper drive spindles about respective sweep angles, wherein the first and second cam arms each have a length of at least 50 mm, and wherein the method comprises reducing the length of the first and / or second cam arm by 10 at least 4 mm.

9. The method of claim 8, wherein the method comprises reducing the length of the first cam arm by approximately 5 mm and reducing the length of the second cam arm by approximately 10 mm.

10. The method of claims 8 or 9, wherein the first link and second links each have a length 15 of at least 250 mm and wherein the method comprises reducing the length of the first and / or second link by at least 50mm.

11. The method of claim 10, wherein the method comprises reducing the length of the first and / or second link by approximately 68 mm.

12. A jig for use in the method of any preceding claim, wherein the jig comprises:20 a first formation configured to locate the first wiper drive spindle with the first axis insaid first orientation prior to cutting the static support member;first and second cutting indicators which define guides for the first and second cut lines respectively; anda second formation configured to locate the separated first end portion with the first 25 wiper drive spindle in said modified position in order to reattach the first end portion to the static support member at the second cut line with the first axis in said second orientation.

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