IMPROVEMENTS IN OR RELATING TO WINDSCREEN WIPERS

Abstract: An elongate windscreen wiper blade harness (30) made of plastics material comprises a first yoke (40) and at least one second yoke (41, 42) articulated thereto by means of a pair of resiliently flexible connecting webs (60a, 60b; 61a, 61b) integrally connecting the second yoke (41, 42) to spaced apart side walls (51, 52) of the first yoke (40) between which the second yoke (41, 42) is at least partly positioned. The invention also embraces an assembly of the wiper blade harness (30) and a wiper arm (31) on which the harness (30) is detachably mounted.

Description: IMPROVEMENTS IN OR RELATING TO WINDSCREEN WIPERS Technical Field This invention relates to a windscreen wiper blade harness of the kind which is made of plastics material and comprises a first yoke, at least one second yoke and resiliently flexible connection means integrally connecting the or each second yoke to the first yoke to enable ar¬ ticulation of the or each second yoke relative to the first yoke. The invention also relates to a windscreen wiper blade assembly comprising a wiper arm and, detachably connectible thereto, a windscreen wiper blade harness cf tne kind referred to. Background Art A known windscreen wiper blade harness of the kind referred to is described in GB-A-1078066. In this known construction there is provided an elongate backing member (or first yoke) to which is integrally connected by the connecting means a plurality of squeegee support members (or second yokes). Each connection means is in the form of a single tongue or connector positioned between the backing member and the squeegee support member concerned in a direction normal to the windscreen in use of the harness. In use of the harness, therefore, the backing member is spaced a relatively large distance from the windscreen. Disclosure of the Invention The present invention seeks to provide a low-level windscreen wiper blade assembly made of plastics material. According to one aspect of the present invention a windscreen wiper blade harness of the kind referred tc, is characterised in that the first yoke has at least one pair of laterally spaced apart walls between which the second yoke(s) is or are positioned and in that the or each connection means comprises a pair of connecting webs integrally connecting the or each second yoke to the pair of spaced apart walls of the first yoke between which the second yoke is positioned. Suitably the or each second yoke is only partly- positioned between the said pa r of spaced apart walls. Preferably τhe or each second yoke comprises an ir.ter- mediate portion between opposite first and second end portions, the or each pair of connecting webs connecting the, or a respective one of the, intermediate porticn(s) tc one, or a respective one, of the ends cf the said spaced apart walls. In this case the said first end portion of the or each second yoke is dimensioned to move between the said spaced apart walls on articulation of the second yoke(s) relative to the first yoke. Preferably the first yoke has two second yokes articu¬ lated by sa d' connection means to opposite end regions of the irst yoke. Each second yoke may have claw means at both of its ends to receive a wiper blade. Alternatively, each end of the second yoke may have a third yoke integral¬ ly connected thereto or one end of the second yoke may have claw means and the other end may have a third yoke in- tegrally connected thereto. In either case each third yoke is conveniently connected tc the second yoke for articula¬ tion relative thereto by further connection means which are conveniently similar to said first mentioned connection means and comprise a pair of further connecting webs integrally connecting a further pair of spaced apart walls of the second yoke between which the third yoke is at least partly positioned. Conveniently the first yoke has attaching means for connecting it to, and supporting it on, a wioer arm. In this case, the first yoke may be substantially flat and act as a main support member for the harness. Suitably the windscreen wiper blade harness is moulded from the said plastics material. Any suitable plastics material, e.g. acetyl plastics material, may be employed. According to a further aspect of the present invention a wiper assembly comprising a windscreen wiper blade harness according to said one aspect of the invention and a wiper arm, is characterised in that the wiper arm comprises a mounting portion and an arm portion articulated thereto, the arm portion being cf channel form and having connection means for detachably connecting the arm portion to the wiper blade harness so that the wiper blade harness is received within the channel section arm portion. According to another aspect of the present invention there is provided a windscreen wiper blade assembly com¬ prising a wiper arm and, detachably connected thereto, a windscreen wiper blade harness according to said one aspect of the present' invention. Brief Description of the Drawings Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawing, in which: Figure 1 is a perspective view of one embodiment of a windscreen wiper blade harness according to the invention, Figure 2 is a perspective view, on a reduced scale, illustrating how the harness of Figure 1 is assembled to a wiper arm and a wiper blade, Figures 3 and 4 are a plan and a longitudinal, partly sectioned view, respectively, of another embodiment of a windscreen wiper blade harness according to the invention and a wiper arm on which the harness is mounted, Figure 5 is a longitudinal sectional view of the wiper arm shown in Figures 3 and 4, Figure 6 is a section, on an enlarged scale, taken on the line VI-VI of Figure 5, Figures 7, 3 and 9 are views, or, enlarged scales, from above, one sice and below, respectively, of the harness shown in Figures 3 and 4, Figure 10 is a section taken or. the line X-X of Figure ~i , Figures 11 and 12 are sections, on enlarged scales, taken on the lines XI-XI and XII-XII, respectively, of Figure 8, Figure 13 is a view, on an enlarged scale, of part of the harness shown in Figure 7, Figure 14 is a view taken on the line XIV-XIV of Figure 13, Figure 15 is a sectional view, taken on tne line XV-XV of Figure 13, of part o the harness, and Figure 16 is a sectional view, taken on the line XVI-XVI of Figure 15, of part of the harness. Best Modes of Carrying Out the Invention Figure 1 shows one embodiment of an elongate wind- screen wiper blade harness according to the invention and generally designated by the reference numeral 1. The harness 1 is moulded from - a plastics material, e.g. an acetyl material, and comprises a generally flat primary or first yoke 2, end or s cond yokes 3 and 4 articulated to opposite end regions of the first yoke 2 and intermediate or third yokes 5 and 6 articulated to the inner ends of the second yokes 3 and 4, respectively. The outer ends of second yokes 3 and 4 are provided with claws 7 and 8, respectively, and similar claws (not shown) are provided on the ends of each of the third yokes 5 and 6. These claws serve to enable a wiper blade 9 (see Figure 2) to be detachably connected to the harness 1. The first yoke 2 consists of two spaced apart side wall parts 12 and 13 and a bridging part 14 joining the side wall parts together at a central region of the yoke. A pivot pin 10 is provided at this central region and enables the harness 1 to be detachably pivotally mounted on a windscreen wiper arm 11 (see Figure 2) by means of attachment means (not shown). The second yokes 3 and 4 are positioned between the spaced apart side wall parts 12 and 13 and are integrally connected to the latter by connection means 15 and 16. Since the harness 1 is symmetrical about the pivot pin 10, the connections of the second yokes 3 and 4 to the first yoke 2 are identical and only the connection of the second yoke 3 to the first yoke 2 will be described in detail hereinafter. Similarly, the connections of the third yokes 5 and 6 to- the second yokes 3 and 4, respec¬ tively, are identical and only the connection of the third yoke 5 to the second yoke 3 wi11 be described in detail hereinafter. The connection means 15 (16) consists of two resil¬ iently flexible connecting webs 15a, 15Jb (16a, 16b_) which integrally connect the second yoke 3 (4) to the side wall parts 12 and 13 to enable the second yoke 3 (4) to articu¬ late relative to the first yoke 2. The two connecting webs 15a and 15b_ (16a and 16b) act as stub "shafts" to enable the second yoke 3 (4) to articulate or turn relative to the first yoke 2. However since the connecting webs are integral bridging connections, they do not provide true pivoting connections and the articulated motion is only possible by the webs being resiliently flexible which enables the webs to be resiliently "twisted" on articula¬ tion of the second yokes relative to the first yoke. By suitably dimensioning the connecting webs 15a, 15b . (16a, 16b . ) and by appropriate selection of the plastics material for the connecting webs, the desired degree of flexibility, resilience and durability of the connection means can be achieved. Furthermore, by designing the connecting webs to be relatively long, e.g. 5 mm, in the elongate direccion of the harness, turning cf the second yoke 3 (4) relati /e tc the first ycke 2 abouτ. an axis perpendicul r tc the elon¬ gate direction and to the pivot pin 10 is virtually elimin¬ ated. Typically, for example, each connecting web 15a, 15 b (16a, 16b . ) will have a _ ickness of up to 2 mm, e.g. 1 mm, and a width in the elongate direction of up to 10 mm or more, e.g. 5 mm. The second yoke 3 (4) has a bifurcated inner end formed by spaced apart side walls 20 and 21 (22 and 23) between which the third yoke 5 (6) is positioned. The third yoke 5 (6) is integrally connected to the second yoke 3 (4) by connection means 24 (25). The connection means 24 (25) are similar to the connection means 15 and 16 and will not be described in detail. However the connection means 24 (25) comprise a pair of resiliently flexible connecting webs which enable the third yoke 5 (6) to articulate relative to the second yoke 3 (4). The windscreen wiper blade harness 1 described herein is of flat, compact design having a low profile. When used on a vehicle windscreen, the low profile of the harness 1 ensures that the harness has a low air or stream resistance. The low profile design is achieved by the provision of laterally extending hinges or webs between the parts of the harness which are designed to enable articula¬ tion of yokes about axes parallel to the pivo_ pin 10 but to resist turning about any other axis. As shown in Figure 1, the side wall parts 12 and 13 of the yoke 2 may be cut out to reduce its weight and the yokes 3-6 may be curved, the yokes 3 and 4 being curved at their outer ends and the yokes 5 and 6 being curved at each of their ends. A further important feature of the harness 1 is that it is made of plastics material and thus the yokes 2-6 are moulded as an integral structure. Assembly of the various parts of the harness (apart, from the pivot pin 10) is thereby eliminatec. The arm 11 shewn in Figure 2 is conveniently designed as a rigid structural casing or guide, e.g. cf channel-like form, intended to surround or shroud the harness 1 along the length of the yoke 2. Thus any tendency of the harness 1 to flex in use out of a longitudinal plane perpendicular to the pivot pin 10 is resisted by the surrounding arm 11. Other designs of windscreen wiper blade harness according to the invention are possible. For example the outer ends of the second yokes 3 and 4 may have further third yokes articulated thereto instead of being provided with claws 7 and 8. Alternatively, the inner ends of the second yokes 3 and 4 could be provided with wiper blade receiving jaws instead of having the third yokes 5 and 6 articulated thereto. A particularly preferred alternative embodiment of windscreen wiper blade harness according to the invention and generally designated by the reference numeral 30 is illustrated in Figures 3-16, the elongate harness 30 being mounted on a wiper arm 31 as shown in Figures 3 and 4. The wiper arm 31 comprises an angled part 32 designed to be connected at its end 32a to a drive shaft (net shown) of a wiper motor and an elongate part 34 connected to part 32 by means of a pivot pin 33. The parts 32 and 34 are of generally channel shaped section and are moulded from plastics material, e.g. an acetyl material (which may be fibre filled for improving rigidity;. A soring 35 normally retains the harness 30 in its operative position (shown in Figure 4) against a windscreen (not shown) although the elongate part 34 may be manually swung away from the windscreen aoout the axis of the pivot pm 33 into an inoperative position (not shown). As can be seen in Figure 6, channels 36 are formed in the bottom of the side walls of the elongate part 34 for receiving, e.g. in a snao-fit, water delivering tubes (not shown) aoertured along their length to deliver water on_o a windscreen to be wiped. The wiper blade harness 31 is moulded in one piece from a plastics material, e.g. an acetyl material (cD_ιon- ally fibre-filled), and comprises a generally flat primary or first yoke 40, end or second yokes 41 and 42 articulated to opposite ends of the first yoke 40 and intermediate or third yokes 43 and 44 articulated to the inner ends of the second yokes 41 and 42, respectively. The outer ends of second yokes 41 and 42 are provided with claws 45 and 46, respectively, and similar claws 47 and 43 are provided on the ends of the third yokes 43 and 44, respectively. These claws serve to enable a wiper blade 49 (see Figure 4} to be detachably connected to the harness 1. The first yoke 40 • consists of two spaced apart side wall parts 51 and 52 and spaced apart bridging parts 53, 54 and 57 joining the side wall parts together at a central region of the yoke. The central bridging part 54 is in the form of an elongate socket 55 for receiving, e.g. m a snap-fit, an integral pivot pin 56 (see Figures 5 and 5) of the elongate wiper arm part 34. A locking piece 57 (see Figure 4) is detachably fitted, e.g. in a snap-fit, to the part 34 for ensuring the pivot pin 56 remains retained in the socket 55 whilst permitting a degree of pivotal move¬ ment of the harness 30 relative to the wiper arm 31 about the pivot pin 56. The second yokes 41 and 42 are partly positioned between the spaced apart side wall parts 51 and 52 and are integrally connected to the latter by connection means 60 and 61. The connection means 60 and 61 each consist of two resiliently flexible connecting webs 60a, 60b_, (61a, 61 b_) which integrally connect the second yoke 41 (42) to ends of the side wall parts 51 and 52 to enable the second yoke 41 (42) to articulate relative to the first yoke 40. The twc connecting ' webs 60a and 5Gb (61a and 61b_) provide integral bridging connections but do not provide true pivoting connections and the articulated motion is only made pos¬ sible by the thin webs being resiliently flexiols. By suitably dimensioning the connecting webs 60a, £Gb_ ;51a, 61b . ) and by appropriate selection of the plastics material for the connecting webs, the desired degree of flexibility, resilience and durability of the connection means can be achieved. Furthermore, by designing the connecting webs tc be relatively long, e.g. 1 cm, in the elongate or lon- gitudinal direction of the harness, turning of the second yoke 41 (42) relative to the first yoke 40 about an axis perpendicular to the elongate direction and to the pivot pin 56 is virtually eliminated. Typically, for example, each connecting web 60a, 60b (61a, 61b_) will have a thick- ness of up to 2 mm, e.g. 1.1 mm. The second yoke 41' (42) has a bifurcated inner end formed by spaced apart side walls 63 and 64 (65 and 56) between which the third yoke 43 (44) is partly positioned. The third yoke 43 (44) is integrally connected to the second yoke 41 (42) by connection means 67 (68). The connecting means 67 (68) comprise a pair of resiliently flexible webs 67a, 67b . (68a, 68b . ) which connect the third yoke 43 (44) to ends of the side walls 63, 64 (65, 55) enabling the third yoke to articulate relative to the second yoke. The outer end portion 42a of the second yoke 42 is of raised form and is designed to cooperate with the recessed end 34a . of the wiper arm part 34 as shown in Figures 3 and 4. In particular the top of the portion 42a . is designed so 5 as to be substantially flush with the top of the wiper arm part 34. The harness 30 and wiper arm 31 provide a cooperating low profile wiper unit with the harness at least partly received between the spaced apart side walls of the wiper 10 arm so that the inverted channel-shaped wiper arm serves as a shroud for the harness 30. The "nested" arrangement of the yokes 40-44 enables the design of a low profile harness 30. The connection means 50, 61 and 67, 68 are in the form of relatively thin flexible connecting webs integrally 15 connecting more rigid yokes together, the integral connec¬ tions enabling the harness to be moulded as a unitary structure. As opposed to the embodiment of Figures 1 and 2, the connecting webs 60a, 60b, 61a, 61b . , 67a τ 67b . , 68a and 68b_ bridge between yokes generally in the longitudinal - 20 direction of the harness 30.

Claims: CLAIMS 1. A windscreen wiper blade harness (30) made of plastics material and comprising a first yoke (40), at least one second yoke (41, 42) and resiliently flexible connection means (60, 61) integrally connecting the or each second yoke (41, 42) to the first yoke (40) to enable articulation of the or each second yoke relative to the first yoke, characterised in that the first yoke (40) has at least one pair of laterally spaced apart walls (51, 52) between which the second yoke(s) (41, 42) is or are posi¬ tioned and in that the or each connection means (60, 61) comprises a pair of connecting webs (60a, 60b . ; 61a, 61b . ) integrally connecting the or each second yoke (41, 42) to the pair of spaced apart walls (51, 52) of the first yoke (40) between which the second yoke (41, 42) is positioned. 2. A harness according to claim 1, characterised in that the or each second yoke (41, 42) is only partly positioned between the said pair of spaced apart walls (51, 52). 3. A harness according to claim 2, characterised in that the or each second yoke (41, 42) comprises opposite first and second end portions and an intermediate portion therebetween, the or each pair of connecting webs (60a, 60b_; 61a, 61b_) connecting the, or a respective one of the, intermediate portion(s) to one, or a respective one, of the ends of the said spaced apart walls (51, 52). 4. A harness according to any one of the preceding claims, characterised in that the first yoke (40) has two second yokes (41, 42) articulated by said connection means (60, 61) to opposite end regions of the first yoke (40). 5. A harness according to claim 4, characterised in that one end of each second yoke is provided with wiper blade receiving claw means (45, 46) and the other end of each second yoke has a third yoke (43, 44) integrally connected thereto, said third yokes being provided with further wiper blade receiving claw means (47-48). 6. A harness according to claim 5, characterised in that each third yoke (43, 44) is connected to the second yoke for articulation relative thereto by further connec¬ tion means (67, 68). 7. A harness according to claim 5, characterised in that each of said further connection means comprises a pair of further connecting webs (57a, 67b . ; 68a, 63b_) integrally connecting the third yoke to a pair of spaced apart walls (63, 64; 65, 66) of the second yoke (41, 42) between which the third yoke (43, 44) is at least partly positioned. 8. A harness according to any one of the preceding claims, characterised in that the first yoke (40) has attaching means (54, 55) for connecting it to, and support¬ ing it on, a wiper arm (30). 9. A wiper blade assembly comprising a windscreen wiper blade harness (31) according to any one of the preceding claims and a wiper arm (30), characterised in that the wiper arm comprises a mounting portion (32) and an arm portion (34) articulated thereto, the arm portion being of channel form and having connection means (56, 57) for detachably connecting the arm portion (34) to the wiper blade harness (31) so that the wiper blade harness is received within the channel section arm portion (34). 10. A windscreen wiper blade assembly comprising a wiper arm (30) and, detachably attached thereto, a wind- screen wiper blade harness according to any one of claims 1 to 8.

Inventors: ROUX CLIVE ANTHONY, VLAM RONALD PETER DE, ROUX, CLIVE, ANTHONY
Applicants: CRISP & WILSON LTD, IRALCO RESEARCH LTD
Application year: 1990
Main classification: B60S1
IPC codes: B60S1