GB2239589A

GB2239589A - A wiper blade unit

Info

Publication number: GB2239589A
Application number: GB9022589A
Authority: GB
Inventors: Liang-Yuan Chen
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: 1990-01-08
Filing date: 1990-10-17
Publication date: 1991-07-10
Anticipated expiration: 2010-10-17
Also published as: GB9022589D0; GB2239589B

Abstract

A wiper blade unit comprising wiping member (201) with anchoring portion (211) and a lip portion (218), backing strip (202) with retaining groove (214) for slidably receiving the anchoring portion of the wiping member and end clip (203) engageable in an opening of the backing strip, providing a retaining groove end stop is provided with projections (213) in the retaining groove adjacent the end of the backing strip at which the end clip is located to resist longitudinal movement of the anchoring portion of the wiping member in a direction away from the end clip. The wiper blade unit may comprise a single blade unit or the backing strip may comprise a single retaining groove for receiving a wiping member having two or more lip portions. <IMAGE>

Description

A WIPER BLADE UNIT This invention relates to a wiper blade unit of the kind comprising an elongate flexible wiping member having an anchoring portion and a wiping head portion, an elongate backing strip connectible to a wiper blade harness and having a retaining groove along its length for slidably receiving said anchoring portion, end means at one end of the backing strip providing a retaining groove end stop for blocking movement of the anchoring portion in a first longitudinal direction relative to said retaining groove when the anchoring portion is retained in the retaining groove, and cooperating means formed in the backing strip and cooperable with said anchoring portion, when the latter is received in said retaining groove, for resisting longitudinal movement of the anchoring portion in a second longitudinal direction relative to the retaining groove opposite to said first longitudinal direction. A wiper blade unit of the kind referred to may be incorporated initially in a wiper blade assembly or may form a refill unit for a wiper blade assembly.

A known wiper blade unit of the kind referred to is shown in -US-A-4177538. In this specification there is disclosed a universal wiper blade unit in which the backing strip is provided with breakage points at predetermined distances from the other end of the backing strip remote from its said one end. Different lengths of the backing strip can thus be "broken" from the other end of the backing strip to form a desired length of backing strip.

In order to prevent longitudinal movement of the anchoring portion of the wiping member within the retaining groove, the end means is provided by an end clip and end clip securing means for securing the end clip to the one end of the backing strip and the cooperating means comprise tabs or projections formed, e.g stamped or pressed, in the backing strip between the breakage points spaced from the other end of the backing strip. The clip securing means conveniently comprises interengaging means on the end clip and backing strip. Thus, typically, the end clip is provided with a projecting part which engages in an end clip retaining opening formed in, and adjacent said one end of, the backing strip.In this case, it is necessary to form the opening at the one end of the backing strip and the tabs or projections spaced from the other end of the backing strip in two separate forming operations which is time consuming and relatively costly.

Another known type of wiper blade unit is described in GB-A-2141621. In this known wiper blade unit, relative longitudinal movement of an anchoring portion of a wiping member received within a retaining groove of a backing strip is prevented by the provision of a U-shaped retention clip having bifurcated legs which pass through aligned holes in side walls of the retaining groove and make snapfit connection with the backing strip. The bifurcated legs pass through a pair of spaced apart notches in the anchoring portion of the flexible wiping member.Thus in order to lock the wiping member in its predetermined position within the retaining groove of the backing strip, it is necessary to provide a special, non-standard retaining clip and to perform the additional operations of forming notches in the anchoring portion of the wiping member and forming aligned openings in the side walls defining the retaining groove of the backing strip. In order that the openings in the side walls receive the bifurcated legs in a snap-fit manner, they have to be well formed. All these features and operations increase the cost of manufacture.

Other known methods of locking the anchoring portion of a flexible wiping member within a retaining groove of a backing strip involve the use of an end clip fitted to one end of the backing strip to close one end of the retaining groove and the provision of stop means at the other end of the backing strip to close the other end of the retaining groove. The stop means may be provided by extrusion deforming the said other end of the extruded backing strip or by forming an inwardly directed projection in wall means defining the ~retaining groove. In both these known methods, the one end of the backing strip has to be provided with end clip retaining means, e.g. an opening for receiving a projecting part of the end clip, and the other end of the backing strip has to be deformed. Thus two separate operations have to be performed on opposite ends of the backing strip.Furthermore, since such known backing strips require stops at either end, they have to be made of different lengths for different types of wiper blade assembly. It is not possible to manufacture these known backing strips of the same standard size which can subsequently be trimmed by a user for use in smaller sizes of wiper blade assembly.

The present invention seeks to provide a wiper blade unit of the kind referred to which overcomes some of the disadvantages associated with known wiper blade units.

According to the present invention a wiper blade unit of the kind referred to is characterised in that the cooperating means are formed closer to said one end than to the said other end of the backing strip.

Since the cooperating means is closer, and preferably substantially closer, to said one end than to said other end of the backing strip, at least half the original length of the backing strip can be trimmed from the other end of the backing strip to produce a backing strip of a desired length without affecting the manner in which the anchoring portion is held against relative longitudinal movement within the retaining groove. Thus a single size of backing strip can be provided which the user can trim to the desired size. The provision of the end means at the said one end of the backing strip will require a pressing or other forming operation to be performed on the backing strip to enable the end stop to be provided.Since the creation of the cooperating means also involves a pressing or other forming operation to be performed on the backing strip, these two operations can be combined in a single forming operation if the cooperating means are at least reasonably close to the end means, e.g. at or adjacent to said one end of the backing strip.

Preferably the end means comprises an end member, e.g.

an end clip, having first engaging means and second engaging means formed in the backing strip at said one end, the first and second engaging means cooperating with each other to connect the end member to said one end of the backing strip to provide an end stop.

Preferably the backing strip comprises wall means defining said retaining groove and provided with inwardly extending integral projection means defining said cooperating means. Preferably the anchoring portion has recess means, e.g. in a single recess or cut out portion, in which the projection means are cooperatively received.

Conveniently the retaining groove is in the form of an elongate channel having an undercut portion and mouth, the anchoring portion of the wiping member having an enlarged base part receivable within said undercut portion and a neck part receivable within said mouth. In this case the wall means defining the channel comprise walls defining the bottom and sides of the channel and a pair of spaced apart top walls extending towards each other with the channel mouth defined therebetween.

In the case where the cooperating means comprise integral projection means, they suitably comprise at least one barb-like projection pressed or stamped from the wall means. Typically the or each barb-like projection has a relatively gently sloping surface over which parts of the anchoring portion are able to slide with relatively little resistance on sliding the anchoring portion along the retaining groove in said first longitudinal direction into a retained position. In the preferred case where recess means are provided in the anchoring portion, the projection(s) is (are) received in the recess means and have abutting surface means for abutment against a wall part of the recess means, when the projection(s) is (are) received in the recess means, to resist sliding of the anchoring portion along the retaining groove in the second longitudinal direction.For example, the or each barb-like projection may be in the form of a finger extending inwardly at an angle of less than 450 In the case where the retaining groove is in the form of an undercut channel, the barb-like projections may be formed in said top walls although, in principle, at least one barb-like projection could alternatively or additionally be formed in the side walls and/or bottom wall. When the projections are formed in said top walls they preferably extend into the said undercut portion of the channel but may also (or alternatively) extend into the said mouth.

The backing strip is preferably made of plastics material. Preferably the backing strip is extruded and the projection means are subsequently formed by a pressing or stamping operation, e.g. when the plastics material is heat-softened.

Preferably the backing strip has elongate side rails for sliding cooperation with claw elements of a wiper blade harness to which the backing strip is intended to be connected. When the end means comprises an end clip having first engaging means interengagable with second engaging means on the backing strip, the end clip serves to cooperate with a claw element of a wiper blade harness to which the backing strip is connected to resist sliding of the cooperating claw element relative to the backing member.

Each side rail may be embraced by a claw part, but preferably each side rail partly defines a side channel in which a claw part is slidingly received.

The backing strip may have two (or more) retaining grooves for retaining two (or more) flexible wiping members. Alternatively (or additionally), the or each flexible wiping member may have two (or more) wiping head portions.

Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which Figures 1 and 2 are schematic perspective views of two prior art wiper blade units, Figure 3 is a sectional view taken on the line 3-3 of Figure 1 or 2, Figures 4 and 5 are perspective views of a wiper blade unit according to the invention in disassembled and assembled conditions, respectively, Figure 6 is a plan from above of a detail of part of the backing strip of the wiper blade unit shown in Figure 4, Figure 7 is a partly sectioned enlarged view of a detail of the backing strip shown in Figure 4, and Figure 8 is a cross-sectional view on an enlarged scale taken on the line V-V of Figure 5.

Figures 1 to 3 show two alternative embodiments of prior art wiper blade refill units each for attachment to a wiper blade harness (not shown) having claw elements. Each prior art wiper blade refill unit comprises an extruded plastics backing strip 22 having a retaining groove 6 for slidably receiving an anchoring portion 11 (see Figure 3) of a flexible wiping member 1. An end clip 3 is detachab ly connected to one end of the backing strip 22, the clip 3 having a projection 4 which extends downwardly (as viewed in Figures 1 and 2) into a hole 5 formed in the backing strip 22. In addition to locking a claw element (not shown) of a wiper blade harness in a known manner to the backing strip, the end clip 3 also serves to block one end of the retaining groove 6 to prevent the anchoring portion 11 from sliding out of the retaining groove 6 at that end.

The other end of the retaining groove 6 is blocked either by forming an inwardly extending stop or projection 23 (see Figure 1) in the backing strip 22 or by deforming the extruded end of the backing strip 22 to act as a stop as shown at 24 (see Figure 2).

Both the prior art wiper blade refill units shown in Figures 1 and 2 have disadvantages. Firstly it is necessary, after extrusion of the backing strips, to perform separate deforming operations at both ends of the backing strips. Secondly, the provision of an end clip at one end of the backing strip 22 and a "stop" a specific distance apart at the other end of the backing strip, characterises the length of the backing strip so that each backing strip produced can only be used with a specific size of wiper blade harness. It is therefore not possible to trim the length of the backing strip to fit smaller wiper blade harnesses without removing either the portion of the backing strip containing the hole 5 or the portion of the backing strip containing the "stop" 23 (Figure 1) or 24 (Figure 2).It would clearly be an advantage to manufacturers only to have to make a one-size refill unit and for retailers only to have to stock a one-size refill unit.

Figures 4-8 show an embodiment of a wiper blade unit in accordance with the present invention. The wiper blade unit illustrated is a twin blade unit and comprises an extruded plastics backing strip 202 defining a pair of spaced apart elongate, upwardly (as viewed in Figure 4) open retaining grooves 214, a pair of flexible elongate wiping members 201 intended to be slidably received in the retaining grooves 214 and each having an elongate wiping head portion .218 and an elongate anchoring portion 211 having an enlarged base part 211a and a narrow neck part 211b. A flange 233 at the bottom (as viewed in Figure 4) of the backing strip 202 defines side rails at opposite sides of the backing strip.These side rails, together with outer walls of the grooves 214, define claw receiving channels 226 for slidably receiving claw elements (not shown) of a wiper blade harness (not shown) for mounting the backing strip to the harness in a conventional manner.

Each retaining groove 214 is defined by a bottom wall 220 (see Figure 8), spaced apart side walls 221 and inwardly extending spaced apart top walls 212. Each groove 214 defined by these walls is in the form of a channel having an undercut portion 230 in which the enlarged base part 211a of the wiping member is received and a mouth 231 in which the neck part 211b is received.

An end clip 203 is attached to one end 234 of the backing strip 202. Typically the clip 203 has an upwardly (as viewed in Figure 8) extending projection 237 which locates in a hole 236 in the flange 233. The end clip has end walls 238 which close the ends of the retaining grooves 214 and inwardly resiliently deflectable spaced apart claw engaging legs 240.

Spaced a preferably short distance from the end 234 of the backing strip 202, each of the top walls 212 is formed with a number, e.g. three, of inwardly extending projections 213. This array of projections is positioned sufficiently far from the end of the backing strip remote from the end 234 to enable the length of the backing strip to be trimmed, from the end remote from end 234, to any desired length without the projections 233 being themselves trimmed from the backing strip. In practice, the array of projections should be positioned closer, preferably substantially closer, to the end 234 of the backing strip than to the other end of the backing strip. The array of projections 213 so provided in the top walls 212 is formed by means of a stamping or pressing operation.Ideally the array of projections 213 should be positioned at least relatively close to the locating hole 236 at or adjacent the end 234 so that the projections 213 and locating hole 236 can be formed in a single stamping/pressing operation by offering the end 234 of the backing strip into a suitable stamping/pressing machine. This stamping/pressing operation may be performed with heated pressing means to heat soften the plastics material of the extruded backing strip and/or may be performed immediately after extrusion when the plastics material may still be in a heat softened condition.

As can be seen in Figures 6-8, the projections 213 are of barb-like form and typically comprise fingers which extend inwardly at an angle, preferably less than 45 , from the top walls 212. The projections primarily are intended to extend into the undercut portion 230 of the channel-like retaining groove 214 but may also (or alternatively) extend into the mouth 231 of the groove.

Each flexible wiping member 201 is preferably provided with a cut-out or recess 111 in its anchoring portion 211.

Each recess 111 has an axial length slightly greater than the axial extent of the array of projections 213 and is positioned so that, when the anchoring portion 211 is slid along the retaining groove and into a final predetermined wiping position, the array of projections 213 project into the recess 111. The barb-like forms of the projections 213 enable the front end of the anchoring portion 211 to slide over the relative gently sloping surfaces of the inclined projections before the projections are received in the recess 111. Reverse movement of the anchoring portion 211 back along the retaining groove 214 is resisted by abutment of the barb-like projections 213 against the end wall of the recess which is closer to the front end of the anchoring portion.This resistance can be overcome by appropriate manipulation of the flexible wiping member 201 and exerting a sufficient pull on the wiping member. However in practice the cooperation between the array of projections 213 and the recess 111 is sufficient to prevent the wiping member from sliding in the reverse direction out of its predetermined wiping position attached to the backing strip 202.

The array of projections 213 when located in the recess 111 also serve to resist further forward sliding of the anchoring portion 211 along the retaining groove.

However the preferred barb-like form of the projections 213 means that their gently sloping surfaces do not offer as great a resistance to forward sliding of the anchoring portion as to resistance to sliding in the reverse direction. However the end walls 238 of the end clip provide additional security to resist this further forward sliding movement. It will be appreciated, however, that in certain circumstances an alternative form of end stop (e.g. of the type shown at 23 and 24 in Figures 1 and 2) to that provided by the end walls 238 of the end clip could be provided. In such cases, a clip similar to end clip 203 but without the end walls 238 could be secured at any convenient position along the backing strip 202 to provide claw location in a known manner.

The projections 213 have been described as being formed in the top walls 212 of the backing strip but alternatively (or in addition) could be formed on the bottom or side walls defining the retaining groove.

The invention has been described with particular reference to a twin blade wiper unit. However the invention provides application in single blade units and/or with a backing strip provided with a single retaining groove for receiving a flexible wiping member having two (or more) wiping head portions. Also the undercut portion of the retaining groove has been described as being defined by spaced apart side walls, a bottom wall and top walls.

However it will be realised that the side and bottom walls could be formed differently, e.g. as a continuous U-shaped wall or as V-shaped walls.

Claims

1. A wiper blade unit comprising an elongate flexible wiping member having an anchoring portion and a wiping head portion, an elongate backing strip connectible to a wiper blade harness and having a retaining groove along its length for slidably receiving said anchoring portion, end means at one end of the backing strip providing a retaining groove end stop for blocking movement of the anchoring portion in a first longitudinal direction relative to said retaining groove when the anchoring portion is retained in the retaining groove, and cooperating means formed in the backing strip and cooperable with said anchoring portion, when the latter is received in said retaining groove, for resisting longitudinal movement of the anchoring portion in a second longitudinal direction relative to the retaining groove opposite to said first longitudinal direction, characterised in that the cooperating means are formed closer to the said one end than the said other end of the backing strip.

2. A wiper blade unit according to claim 1, in which the end means comprises an end member having first engaging means and second engaging means formed in the backing strip adjacent said one end, the first and second engaging means cooperating with each other to connect the end member to said one end of the backing strip to act as said end stop.

3. A wiper blade unit according to claim 1 or 2, in which the backing strip comprises wall means defining said retaining groove and provided with inwardly extending integral projection means defining said cooperating means.

4. A wiper blade unit according to claim 3, in which the anchoring portion has recess means therein in which said projection mears are received when the anchoring portion is received in the retaining groove.

5. A wiper blade unit according to any of the preceding claims, in which the retaining groove is in the form of an elongate channel having an undercut portion and a mouth, the anchoring portion of the wiping member having an enlarged base part receivable within said undercut portion and a neck part receivable within said mouth.

6. A wiper blade unit according to claim 5 when dependent on claim 3 or 4, in which the wall means defining the channel comprise walls defining bottom and sides of the channel and a pair of spaced apart top walls extending towards each other with the channel mouth defined therebetween.

7. A wiper blade unit according to any of the preceding claims, in which the cooperating means comprise at least one barb-like projection pressed or stamped from the backing strip for cooperation with the anchoring portion of the wiping member.

8. A wiper blade unit according to claim 7, in which the or each barb-like projection has a relatively gently sloping surface over which parts of the anchoring portion are able to slide with relatively little resistance on sliding the anchoring portion along the retaining groove in said first longitudinal direction into an in use position.

9. A wiper blade unit according to claim 7 or 8, each when dependent directly or indirectly on claim 4, in which the or each projection has an abutting surface for abutment against a wall part of the recess means, when the projection(s) is (are) received in the recess means, to resist sliding of the anchoring portion along the retaining groove in said second longitudinal direction.

10. A wiper blade unit Eccording to claim 7, 8 or 9, in which the or each barb-like projection is in the form of a finger extending inwardly at an angle of less than 450 to the wall from which it projects.

11. A wiper blade unit according to any of claims 7 to 10, each when dependent directly or indirectly on claim 6, in which the barb-like projections are formed in said top walls.

12. A wiper blade unit according to any of claims 7 to 11, each when dependent directly or indirectly on claim 6, in which at least one barb-like projection is formed in the walls defining the bottom and sides of the channel.

13. A wiper blade unit according to claim 11 or 12, in which the projections extend into the said undercut portion of the channel and/or into the said mouth.

14. A wiper blade unit according to any of the preceding claims, in which the backing strip is made of plastics material.

15. A wiper blade unit according to claim 14, in which the backing strip is extruded, the cooperating means having been subsequently formed by a pressing/stamping operation with the plastics material in a heat-softened condition.

16. A wiper blade unit according to any of the preceding claims, in which the backing strip has elongate side rails for sliding cooperation with claw elements of a wiper blade harness to which the backing strip is intended to be connected.

17. A wiper blade unit according to any of the preceding claim, in which the backing strip has at least two retaining grooves for retaining at least two flexible wiping members.

18. A wiper blade unit according to any of the preceding claims, in which the or each flexible wiping member has at least two wiping head portions.

19. A wiper blade unit constructed and arranged substantially as herein described with reference to, and as illustrated in, Figures 4 to 8 of the accompanying drawings.

20. A wiper blade assembly comprising a wiper blade harness and a wiper blade unit as claimed in any of the preceding claims detachably attached thereto.

21. A wiper blade unit comprising an elongate flexible wiping member having an anchoring portion and a wiping head portion, an elongate backing strip connectible to a wiper blade harness and having a retaining groove along its length for slidably receiving said anchoring portion, end means at one end of the backing strip providing a retaining groove end stop for blocking movement of the anchoring portion in a first longitudinal direction relative to said retaining groove when the anchoring portion is retained in the retaining groove, and cooperating means formed in the backing strip and cooperable with said anchoring portion, when the latter is received in said retaining groove, for resisting longitudinal movement of the anchoring portion in a second longitudinal direction relative to the retaining groove opposite to said first longitudinal direction, characterised in that said cooperating means are formed at least relatively close to said end means at or adjacent to said one end of the backing strip.