GB2257027A

GB2257027A - A windscreen wiper blade assembly

Info

Publication number: GB2257027A
Application number: GB9114620A
Authority: GB
Inventors: Cedric Sheng Kao Charng
Original assignee: CHINA WIPER SPECIAL RUBBER CO; China Wiper Special Rubber Co Ltd
Current assignee: CHINA WIPER SPECIAL RUBBER CO; China Wiper Special Rubber Co Ltd
Priority date: 1991-07-05
Filing date: 1991-07-05
Publication date: 1993-01-06
Anticipated expiration: 2011-07-05
Also published as: GB9114620D0; GB2257027B

Abstract

A windscreen wiper blade assembly comprises a first yoke 1 having joined thereto, at one or both of its ends, a second yoke 5. The or each joint between the first and second yokes 1 and 5 is provided by a channel shaped plastics joint member 6 having outwardly projecting pivot pins 20, 21 interengaging with pivot holes (22, 23) in walls of the first yoke 1 for securing the joint member to the first yoke. The inner surface of the side walls (10, 11) of the joint member 6 and the confronting outwardly facing sides of the second yoke 5 have cooperating portions, e.g. projecting portions (9a, 9b, 13, 14), which cooperate with each other to retain the joint member 6 on the second yoke 5. Clearance spaces are formed between the parts of the joint member side walls (10, 11) and the outwardly facing sides (7, 8) of the second yoke 5. <IMAGE>

Description

A WINDSCREEN WIPER BLADE ASSEMBLY This invention relates to a windscreen wiper blade assembly of the kind comprising a first yoke having spaced apart first side walls and a connecting wall together defining a channel member, a channel shaped joint member having resiliently deflectable, spaced apart second side walls received between said spaced apart first side walls and a second yoke received between said spaced apart second walls and having spaced apart outwardly facing sides.

A known windscreen wiper blade assembly of the kind referred to is described in GB-B-2011250. In this known wiper blade assembly, the first yoke is metallic and the free ends of the spaced apart first side walls have inwardly turned tongues which engage in corresponding tonguereceiving pockets formed in the spaced apart second side walls. One disadvantage of this known windscreen wiper blade assembly is that in order to assemble the latter it is necessary initially for the first side walls to diverge to leave sufficient room for the joint member to be received between the spaced apart first side walls. It is then necessary, as a subsequent assembly step, to move the first side walls from their diverging disposition into a substantially parallel disposition so that the tongues are caused to interengage in the tongue-receiving pockets.Thus the assembly procedure involves the step of using a special bending tool or machine to bend the metallic first side walls of the first yoke from a diverging disposition to a substantially parallel disposition.

Another known windscreen wiper blade assembly of the kind referred to is described in GB-A-2159697. As with the wiper blade assembly described in GB-B-2011250, the channel shaped joint member rests within, being orientated in the same direction as, the channel shaped first yoke.

A yet further known windscreen wiper blade assembly of the kind referred to is described in EP-A-0405837. In this known wiper blade assembly the first yoke is of channelshaped form and is oriented in the opposite direction to the channel-shaped joint member. The second side walls are joined by a web and each second side wall has a distal portion, remote from the web, having an outwardly extending pivot pin engaging in a pivot hole formed in the adjacent first side wall and a proximal portion, adjacent the web, having an inwardly projecting rib. The second yoke has cut away side walls which are received between the inwardly projecting ribs and web of the joint member to retain the second yoke in position. One disadvantage of this known design of wiper blade assembly is that the cut away side walls of the second yoke may unduly weaken the second yoke.

The present invention seeks to provide an improved windscreen wiper blade assembly of the kind referred to in which the channel shaped joint member is oriented in the opposite direction to the channel member.

According to one aspect of the present invention there is provided a windscreen wiper blade assembly including a first yoke having spaced apart first side walls and a connecting wall which together define a channel member, a channel shaped joint member oriented in an opposite direction to said channel member and having resiliently deflectable spaced apart second side walls received between said spaced apart first side walls and a second yoke received between said spaced apart second side walls and having spaced apart outwardly facing sides, the inner surface of each second side wall and the confronting outwardly facing side of the second yoke having cooperating portions which cooperate with each other to retain the joint member on the second yoke and which provide a clearance space between a part of the outwardly facing side of the second yoke and the confronting inner surface of a part of said second side wall which has a pivot pin projecting outwardly therefrom, each of the said second side wall parts being resiliently movable inwardly into said clearance space for moving each pivot pin inwardly between an outer position, for engagement in an associated pivot hole formed in the associated outwardly adjacent first side wall, and an inner position out of engagement with said associated pivot hole.

In order to assemble the second yoke to the first yoke in a windscreen wiper blade assembly according to the invention, the first side walls are initially resiliently urged apart, to enable the second yoke to be located there between, and are then allowed to resiliently return towards each other so that the said cooperating portions cooperate with each other with the joint members being retained by the second yoke. The second side wall parts are then resiliently moved into their associated clearance spaces so that the pivot pins of the joint member can be moved between the spaced apart first side walls before engaging in their associated pivot holes.

Preferably a camming groove is formed in the inner surface of each first side wall leading from the pivot hole to the free end of each first side wall remote from the connecting wall. Each camming groove is intended to receive its associated pivot pin and to urge the latter resiliently inwards during assembly as the assembled second yoke and joint member are moved between said spaced apart first side walls.

Conveniently the first and/or second yoke are/is metallic.

Preferably the first yoke has separate second yokes pivotally connected to channel members at opposite ends of the first yoke by separate joint members.

Conveniently the cooperating portions comprise outwardly projecting portions of the outwardly facing sides of the second yoke and inwardly projecting portions on, and/or recesses in, the inner surfaces of said second side walls.

An embodiment of the invention will now be described by way of example only, with reference to the accompanying drawings, in which Figure 1 is a partly sectioned schematic perspective view, on an enlarged scale, of part of a windscreen wiper blade assembly according to the invention and showing a secondary yoke joined to a primary yoke by means of a joint member, Figure 2 is a schematic perspective view of a secondary yoke, Figure 3 is a perspective view of a joint member, and Figures 4 and 5 are sectional views through the joint between the primary yoke and a secondary yoke taken on the lines IV-IV and V-V, respectively, of Figures 5 and 4.

The drawings show a windscreen wiper blade assembly according to the invention comprising a metallic main or first yoke 1 having, at each of its opposite ends (only one end of which is shown in Figure 1), spaced apart side walls 2,3 connected by web 4 which together provide an inverted channel shape, second yokes 5 (only one of which is shown in the drawings) at opposite ends of the first yoke 1 and a joint member 6 made of plastics material connecting each second yoke 5 to a respective end of the first yoke 1. The second yoke 5 has spaced apart outwardly facing sides 7 and 8 and the joint member 6, which is channel shaped but oriented in an opposite direction to the channel shaped ends of the yoke 1, has spaced apart second side walls 10 and 11 connected by a web 12. The second yokes may have claws at one or both of their opposite ends for embracing, in a conventional manner, a backing strip (not shown) holding a squeegee element (not shown). Alternatively, one or both of the opposite ends of each second yoke may be pivotally connected to a third yoke (not shown). The precise yoke design of the assembly is not important and the invention is primarily directed to the joint or joints between any two yokes of a wiper blade assembly. Each of the second yokes may be made of plastics material, e.g. shown in Figures 1 and 2, or of a metallic material (see Figures 4 and 5 in which the second yoke is of channel form). Each of the sides 7 and 8 is provided in a central region of the second yoke with a pair of spaced apart angular shaped projections 13 and 14.In particular the projections comprise spaced apart parallel portions 13a and 14a extending from top to bottom of the sides 7 and 8 and lengthwise extending portions 13b and 14b. The projections 13 are generally Lshaped and the projections 14 are each generally the mirror image of an L-shape.

Each of the side walls 10 and 11 has a pair of inwardly extending, rectangular cross-section projections 9a and 9b at their two corners remote from the web 12. Aligned pivot pins 20 and 21, each with an angled end face portion 20a and 21a, extend outwardly from the side walls 10 and 11, respectively, and interengage with pivot holes 22 and 23, respectively, formed in the side walls 2 and 3.

In order to assemble the wiper blade assembly from its various components, the side walls 10 and 11 are initially resiliently spread slightly apart to enable the second yoke 5 to be pushed downwardly (as viewed in Figure 4) relative to the joint member 6 between the spaced apart upstanding side walls 10 and 11 thereof. The walls 10 and 11 are allowed to return under their own resilience to their normal position so that the projections 9a and 9b cooperate with the projections 13 and 14, respectively, to retain the joint member 6 in a mounted position with its side walls embracing the sides of the second yoke. In particular the projection 9a on each side wall 10,11 is received in the angle between the portions 13a and 13b and the projection 9b on each side wall 10,11 is received in the angle between the portions 14a and 14b.A clearance space (see Figure 5) is formed between the inner wall surface of the wall part of each wall 10 and 11 which has the pivot pins 20 and 21 extending therefrom and the adjacent outwardly facing side 7 or 8. The joint member 6 and the retained second yoke 5 are then positioned adjacent one end of the first yoke 1 with the side walls 10 and 11 extending upwardly from the web 12 and the side walls 2 and 3 extending downwardly in the opposite direction from the web 4. The joint member 6 is then moved upwardly between the walls 2 and 3 so that the angled end face portions 20a and 21a engage the inside surfaces of the walls 2 and 3 causing the parts of the spaced apart side walls 10 and 11 from which the pivot pins extend to be resiliently deflected inwards towards each other as the joint member 6 moves upwardly between the rigid side walls 2 and 3.This inward movement of the wall parts is made possible by the provision of the previously mentioned clearance spaces between parts of the walls 10 and 11 and the facing sides 7 and 8. Eventually the free outer ends of the pivot pins 20 and 21, as they are moved upwardly against the inside surfaces of the spaced apart side walls 2 and 3 of the first yoke 1, reach the pivot holes 22 and 23 and resiliently spring outwardly thereinto.

Each side wall 10, 11 has an outwardly extending flange 10a, lla, respectively, formed at one of its ends. These flanges 10a and lla are positioned adjacent the ends of the side walls 2 and 3, respectively, when the pivot pins 20 and 21 are engaged in the pivot holes 22 and 23, respectively.

The joint member 6 is fixed fast with the second yoke 5 and the joint member and yoke 5 are able to rock or pivot slightly relative to the yoke 1 about the pivot pins 20 and 21.

It will be appreciated that the inside surfaces of the rigid side walls 2 and 3 and the sloping end faces 20a and 21a which engage these side walls as the joint member 6 and yoke 5 are moved upwardly, relative to the yoke 1, immediately prior to engagement of the pivot pins 20 and 21 in the pivot holes 22 and 23, provide a camming action resiliently urging the pivot pins, and the wall parts from which the pivot pins extend, inwardly towards each other.

As an alternative to, or in addition to, providing the sloping end faces 20a and 21a, grooves 30 (shown in dashed lines in Figure 4) may be provided in the inner surfaces of the walls 2 and 3 extending between each pivot hole 22, 23 and the side wall end remote from the web 4. During assembly, the free ends of the pivot pins are initially received in these grooves 30 and are dimensioned to urge the pivot pins towards each other as the pivot pins 20 and 21 are subsequently moved upwardly between the side walls 2 and 3 before engaging in the pivot holes. This camming action is conveniently achieved by making each groove gradually shallower along its length in the direction towards its associated pivot hole.

Claims

1. A Windscreen blade assembly including a first yoke having spaced apart first side walls and a connecting wall which together define a channel member, a channel shaped joint member oriented in an opposite direction to said channel member and having resiliently deflectable spaced apart second side walls received between said spaced apart first side walls and a second yoke received between said spaced apart second side walls and having spaced apart outwardly facing sides, the inner surface of each second side wall and the confronting outwardly facing side of the second yoke having cooperating portions which cooperate with each other to retain the joint member on the second yoke and which provide a clearance space between a part of the outwardly facing side of the second yoke and the confronting inner surface of a part of said second side wall which has a pivot pin projecting outwardly therefrom, each of the said second side wall parts being resiliently movable inwardly into said clearance space for moving each pivot pin inwardly between an outer position, for engagement in an associated pivot hole formed in the associated outwardly adjacent first side wall, and an inner position out of engagement with said associated pivot hole.

2. A wiper blade assembly according to claim 1, in which the first yoke has a separate second yoke pivotally connected to each of its opposite ends by means of a separate joint member.

3. A wiper blade assembly according to claim 1 or 2, in which the said cooperating portions comprise outwardly projecting portions of the outwardly facing sides of the second yoke and inwardly projecting portions on, and/or recesses in, the inner surfaces of said second side walls.

4. A blade assembly according to claim 3, in which each of the said outwardly facing sides of the second yoke has a pair of said outwardly projecting portions each of angular form, e.g. an L-shape and a mirror image of an Lshape.

5. A blade assembly according to any one of the preceding claims, in which the first yoke is metallic.

6. A blade assembly according to any one of the preceding claims, in which the second yoke is metallic.

7. A blade assembly according to any one of the preceding claims, in which the free end surface of each pivot pin is angled to assist inward deflection of the said second side wall parts as the joint member is inserted between the spaced apart first side walls during assemblage of a windscreen wiper blade assembly.

8. A blade assembly according to any one of the preceding claims, in which the or each second yoke is channel shaped and has a web connecting spaced apart third side walls.

9. A windscreen wiper blade assembly constructed and arranged substantially as herein described with reference to, and as illustrated in, Figures 1 to 5 of the accompanying drawings.