GB2336765A

GB2336765A - A wiper assembly

Info

Publication number: GB2336765A
Application number: GB9809370A
Authority: GB
Inventors: Peter Lumsden; David James Haggett; Steven Robert Fannon; Geert Anna Pieter Reubzaat
Original assignee: MG Rover Group Ltd
Current assignee: MG Rover Group Ltd
Priority date: 1998-05-02
Filing date: 1998-05-02
Publication date: 1999-11-03
Also published as: WO1999056992A1; GB9809370D0; AU3716899A

Abstract

An integral wiper assembly 1 is provided which comprises a plurality of tiered beams formed into at least a first beam tier 2 and a second beam tier 3. The assembly including coupling means 6 between tiered beams in order to allow lateral displacement of the respective beams in order to provide appropriate load distribution and deformation of the wiper assembly to accommodate various motor vehicle windscreen curvature profiles. The wiper assembly includes a wiper blade 5 secured to the assembly generally through a blade carrier 7 which in turn is coupled to the tiered beams appropriately coupled together by the coupling means 8. The present wiper assembly provides for lateral displacement of the respective tiered beams to give better consistency with windshield curvature than previous integral wiper assemblies whilst avoiding the necessity of slide couplings between respective tiers, typical in prior wiper assemblies.

Description

2336765 A WIPER ASSEMBLY The present invention relates to a wiper assembly

and more particularly, but not exclusively, to a wiper assembly secured to a newly manufactured vehicle to allow delivery thereof. Thus, the wiper assembly has particular applicability to p seudo- disposable components temporarily used to allow such delivery but being sufficiently inexpensive to allow ready disposal after the inherent wiper blade degradation as a result of ship board transportation, etc. However, by use of acceptable materials, the present invention may be used as a conventional duty wiper for driving purposes.

It will be appreciated that wiper blades for a motor vehicle, as with most other elastomeric materials, degrade with time and environmental attack. Such degradation is particularly prevalent with cheaper rubbers and when the blade is subjected to harsh conditions such as upon exposed storage sites or aboard a transportation ship at sea. However, during delivery of a motor vehicle it is necessary to provide a wiper assembly of sufficient functionality to allow manoeuvring of the vehicle into and out of transports, etc. Thus, it is necessary to provide a wiper assembly upon a new vehicle for delivery which is then removed and replaced by a longer service wiper assembly. This longer service wiper assembly can be of the same type as that used for delivery or not but, irrespective of the use for delivery or conventional duty, there is an ongoing objective, as with all consumable parts, to provide the cheapest wiper assembly for the longest service life.

Due to their complexity, it will be appreciated that wiper assemblies are relatively expensive. It is important that a wiper blade of a wiper assembly is appropriately presented upon a windscreen in order to clear that screen in an efficient manner. In order to achieve such load spread and conformity with the windscreen, the wiper assembly must include various hinge and slide mechanisms. In such circumstances, the wiper assembly is relatively complex to assemble, manufacture, in terms of parts and their tolerance, and protect from environmental damage. Unfortunately, such features are generally inconsistent with provision of a cheap readily disposable wiper assembly necessary for short motor vehicle delivery requirements.

Plastics materials provide an opportunity to make an integrated wiper assembly for a motor vehicle. Thus, in International Patent Publication No. W096121587 and International Patent Publication No. W098101329, integrated wiper assemblies are described. The description and teaching of these documents is incorporated into the present application by way of reference. Essentially, these patent applications describe forming from a plastics material a force distribution arrangement necessary to provide adequate windscreen wiping for a motor vehicle. The arrangement comprises primary, secondary and tertiary beams secured together through coupling sections in order to appropriately distribute a load generally applied centrally upon the primary beam of the arrangement. Thus, by appropriate location of the couplings between the primary, secondary and tertiary beams at intermediate positions along the length of the secondary and tertiary beam, load distribution can be controlled as presented through a wiper blade secured to the respective tertiary beams. The principle of operation is accepted engineering practice for weight distribution from a notionally central application point but inherently achieves, in the context of a wiper assembly for a motor vehicle, an appropriate arrangement for distribution of load to a wiper blade through a single integral plastics material component unitarily moulded.

Unfortunately, an integral wiper assembly as described above still provides problems of complete equalisation of load across the wiper blade "and providing sufficient flexibility to allow presentation of a wiper blade consistent with the curvature of a motor vehicle windscreen.

It is an object of the present invention to provide a wiper assembly which can be readily made from an integral plastics material, but which avoids the above-mentioned problems.

In accordance with the present invention there is provided a wiper assembly for a motor vehicle, the assembly comprising tiered beams coupled together in a hinged cascade to present, in use, a wiper blade to a windscreen of a motor vehicle, said tiered beams being arranged in at least two tiers with ends of one tiered beam in a first beam tier coupled through coupling means to intermediate portions of respective tiered beams of a second beam tier, the assembly characterised in that the coupling means is configured to allow significant lateral movement in the longitudinal axis of the wiper blade along with hinge movement thereabout to facilitate even load presentation and consistency with a presented windscreen of a motor vehicle.

Preferably, the wiper assembly includes load application means secured intermediate the first beam tier.

The coupling means may comprise undulating components configured to achieve axial deformation. Thus, the coupling means"may be corrugated or include a 180 tour/meander between respective tiered beams or have an eccentric shape determined as required by load and deformation or include substantially perpendicular bends in order to facilitate respective perpendicular axial deformations. The coupling means may be assembled such that undulations, etc, are perpendicular or lateral in the wiper assembly.

The coupling means may be made from an elastomeric material and may be configured to give varying resilience in different axes such that the coupling means may be stiffer in a perpendicular or a lateral axis of the wiper assembly.

The wiper assembly is preferably integrally formed from a plastics material. The assembly may comprise one tiered beam forming the first beam tier, two beams forming the second beam tier and four beams forming a third beam tier coupled to a wiper blade, the tiered beams being coupled together through coupling means.

Preferably, in a relaxed unloaded state, the assembly is configured to have a slight curvature of large relative radius in order to initiate desired bend into contact with a windscreen under load.

The present invention also includes a method of making a wiper assembly in which a plastics material is presented in a mould having appropriately configured relief recesses to form the wiper assembly.

Furthermore, the method may include presenting differential plastics materials or elastomeric materials in respect of each tiered beam andlor the wiper blade through a multi-part moulding process such that these various parts become fusion bonded as a result of the moulding process.

Embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings, in which:

Figure 1 illustrates, in pictorial front elevation, a first embodiment of an integral wiper assembly; Figure 2 illustrates, in pictorial front elevation, a second embodiment of a wiper assembly; Figure 3 is a pictorial front elevation of a third embodiment of a wiper assembly; Figure 4 is a pictorial front elevation of a fourth embodiment of a wiper 10 assembly; and Figure 5 is a pictorial front elevation of a fifth embodiment of a wiper assembly.

As indicated above, it is important with a wiper assembly for a motor vehicle to provide both even load distribution and acceptable deformation to allow consistency between a wiper blade of the assembly and a motor vehicle's windscreen curvature. Traditionally, such load distribution and deformation has been achieved through relatively complex assemblies of metal components including slide hinges and pivots to appropriately present a wiper blade of the assembly to a windscreen. Such assemblies are relatively robust and so provide good long term use but as also indicated above can be expensive in situations such as that described with regard to vehicle delivery. In such circumstances, a relatively cheap integral assembly is preferred. However, sufficient functionality must be retained through load distribution and deformation to give the assembly a reasonable life time sufficient to allow delivery of the vehicle. Once delivery of the vehicle is achieved, more robust traditional wiper assemblies may replace the integral unit in order to achieve a long service life. A wiper assembly is simply a unit attached to the vehicle's wiper motor mechanism, etc, through a wiper arm.

Provision of a single unitary assembly of a plastic backer beam with a rubber wiper blade will generally produce a Gaussian type load distribution which will be unacceptable for wiper assembly functionality upon a motor vehicle. With vehicle delivery there is a particular problem as the wiper assembly will be required to displace heavy dusting as a result of the vehicle being stored in a relatively open storage unit or transported on board a ship or low-loader, etc. In order to achieve load spreading cascades of wiper assembly beams can be provided as described in International Patent Publication No. W098/01329. These beams are generally secured together through "live" elements to present a wiper blade.

In Figure 1 a pictorial front elevation of a wiper assembly is depicted. The assembly 1 comprises a number of tiered beams 2, 3, 4 coupled together to provide support and presentation of a wiper blade 5 to a motor vehicle windscreen (not shown). These beams 2, 3, 4 are arranged in a cascaded tiered configuration in order to distribute a load F presented to the assembly 1. Thus, the wiper blade 5 will present the load F to a vehicle windscreen and will also deform for consistency with the curvature of that windscreen. Such deformation and load distribution is achieved through hinge couplings 6 and spring resilient coupling beams 4.

The configuration as illustrated in Figure 1 is relatively conventional in terms of cascade distribution in the force F. However, in accordance with the present invention, it will be noted that respective couplings between the beams 2, 3, 4 in their respective tier are substantially all in the same plane X-X in order to avoid undesirable longitudinal loads transmitted as a result of wiper blade 5 flexing in use. Thus, secondary beams 3 are secured about hinge couplings 6 to a primary beam 2. These secondary beams 3 are joined to the wiper blade 5 through tertiary beams 4 which have a spring resilience. Typically, the assembly 1 includes a wiper blade carrier 7 which extends the whole width of the assembly 1 in order to accommodate a wiper blade 5. The blade carrier 7 is configured with a curve so that it will conform to a typical curved windscreen of a motor vehicle without undue deflection. Thus, the assembly 1 may have a slight curve of large radius in order to promote and initiate good deformation into contact with a windscreen. Normally, the tertiary beams 4, including their spring resilience are equally spaced along the width of the assembly in order that the load F applied through the assembly 1 to the blade carrier 7 by the main beam 2 and the secondary beams 4 is equally distributed therethrough. The hinge couplings 6 will pivot to allow the secondary beams 3 to rotate thereabout. In such circumstances the blade carrier 7 can deform to screen curvatures which differ from the curve inbuilt into that blade carrier 7. It will be appreciated that the main beam 1 is a substantial solid component resistive to deformation and flexible under the load F. Thus, the present wiper arrangement presents a curved wiper blade 5 to a windscreen more consistent with that windscreen's curvature rather prior arrangements which present a linear, ie. flat compliance unrepresentative of an actual motor vehicle windscreen. Such curved presentation of the wiper blade 5 along with more even load F distribution there across provides enhanced windscreen wiper function within a motor vehicle.

In order to achieve such curvature of presentation of the wiper blade 5, it will be appreciated that the assembly 1 must allow, in addition to rotation about the hinge coupling 6, lateral displacement of the coupling tertiary beams 4 in the direction of the major longitudinal axis of the wiper blade 5. Thus, the hinge coupling 6 and/or the tertiary beam 4 must facilitate such lateral movement in the longitudinal axis of the wiper blade 5. As indicated previously, wiper assemblies have included hinge couplings which have allowed slide movement to accommodate such lateral displacement.

However, it will be appreciated within an integral moulding, provision of such sliding hinges or couplings is difficult as a mechanical displacement or motion is required which is contrary to component integration. However, those skilled in the art will appreciate that with sophisticated plastics moulding technology, it may be possible to provide such a slide hinge through simultaneous extrusion encapture of reciprocal interference components but such couplings are not within the scope of the present invention.

The present invention provides an integral wiper assembly 1 which allows lateral displacement in the longitudinal axis of a wiper blade 5. Thus, in Figure 1, each tertiary beam 4 is coupled to its secondary beam 3 and the blade carrier 7 through perpendicular elbow joints 8, 9 in order to facilitate such lateral deformation through opposed rotation about the perpendicular junction of each elbow joint 8, 9 with its beam 4. It will be appreciated that clockwise rotation of elbow joint 8 will generally be reciprocal to anti-clockwise rotation of elbow joint 9 and vice versa with the result that in such opposed configuration the blade carrier 7 and its coupled wiper blade 5 will be appropriately presented by the assembly 1. Furthermore, as a result of such rotations of the elbow joints 8, 9 it win be understood that the tertiary beams 4 can adopt a range of slight inclinations in order to achieve the desired curvature of presentation required for effective wiper assembly 1 functionality.

Those skilled in the art will appreciate that, when using plastics materials, mechanical strength can be achieved or controlled through material thickness. Thus, as depicted in Figure 1, it will be appreciated that there are substantial thickness differentials between the primary beam 2, each secondary beam 3 and each tertiary beam 4 with the result that each of these beams has a differential stiffness response to the load F with the desired distribution both of that load F across the wiper blade 4 and with regard to deformation of the assembly 1 to a windscreen's curvature under the load F applied.

Alternatively, and also in accordance with the present invention, multicomponent moulding can be utilised in order to make the wiper assembly 1. In such circumstances, a mould will either receive differential plastics material(s) at different injection points for each beam 2, 3, 4 along with couplings 6 and elbow joints 8, 9. Furthermore, the wiper blade which will generally be of an elastomeric rubber material may be similarly injected into the mould in a simultaneous operation to form the assembly 1. In such circumstances, all the components of the assembly 1 will be fusion bonded together to provide an integral structure. As already intimated with regard to the wiper blade 5, an alternative, to separate injection of plastics materials and different injection points in a mould to create the assembly 1, is to pre-insert components such as the wiper blade 5 into the mould and then inject plastics material about that insert in order to create the assembly 1. In such circumstances, again the various components of the 5 assembly 1 will be fusion bonded together into an integral structure. Finally, several wiper assemblies could be made in one injection moulding stage through provision of a mother preform possibly including several blade elements 5 such that plastics materials injected into the mould to create the preform and then this preform is sliced, ie. each slice including 10 one blade element 5 to create a number of wiper assemblies 1. Alternatively, the pre-form could be extruded. It will be appreciated that forming several assemblies 1 in one manufacturing stage will further reduce the cost of each assembly 1 and so increase its acceptability as a disposable item.

It will be appreciated that tiered beams 2, 3, 4 in accordance with the present invention facilitate load distribution throughout the length and width of a wiper blades. However, it is lateral displacement which achieves the appropriate presentation of the blade upon a curved motor vehicle windscreen. Such lateral displacement is the difficulty inherent with providing an integral wiper assembly whether it be made from a plastic or any other material. Essentially, this lateral deformation can be provided through a tertiary beam 4, couplings 8, 9 or as indicated in Figure 2, more directly through a blade carrier coupling 27. In the embodiment depicted i 1 in Figure 2, it will be seen that a primary tiered beam 20 is coupled to two secondary beams 23 through hinge couplings 26. Thus, a wiper assembly 21 is similar thus far to that depicted in Figure 1 as assembly 1. However, the secondary beams 23 are now directly coupled to the blade carrier coupling 27 through couplings 28.

The blade carrier coupling 27 has a corrugated or undulating configuration and so, if desired, the arch of respective undulations to which the couplings 28 are secured could be considered as tertiary beams depicted in Figure 1. In any event, the couplings 28 do not generally require to be dynamic in any respect in that deformation is readily achieved by the corrugations or undulations between these couplings 28 within the blade carrier 27. It will be appreciated that the serpentine or corrugated undulation of the coupling 27 could be integral within a wiper blade 25 if required.

In Figure 3, a wiper assembly 31 is depicted which comprises a first beam tier A-A formed.from a primary beam 32 coupled to a wiper blade carrier 37 and so wiper blade 35. Coupling between the primary beam 32 and the carrier 37 is via respective central beam couplings 38 and peripheral beam couplings 39. These couplings 38, 39 include tiered beam segments 33 and 34. These tertiary beam segments 33, 34 define a second beam tier B-13. Again, lateral deformation of the carrier 37 and blade 35 is achieved through deformation of the couplings 38, 39. It will be appreciated that deformation response between the central couplings 38 is typically different to that requirement of the peripheral couplings 39. Thus, the central couplings 38 essentially comprise either side of the beam portion 33 deformation loops 30 and 36 arranged in a substantially perpendicular relationship to each other. It will be appreciated that loops 30, 36, each allow rotary displacement about the apex of each loop 30, 36 and so in combination loops 30, 36 will accommodate a range of orientation deformations and therefore also of the carrier 37 along with blade 35. Similarly, peripheral couplings 39 include respective loops 34 substantially in series between the beam 32 and the carrier 37. Thus, it will be appreciated displacement substantially perpendicular to the carrier 37 is readily achieved by the spring combination of series loops 34 whilst lateral deformation is achieved through rotation about the contact mountings with respect to the beam 32 and the carrier 37. Normally, and as appreciated, several couplings 38, 39 will be included in order to provide the necessary load distribution and deformation to accommodate windshield curvature in a motor vehicle.

Figure 4 illustrates a fourth embodiment of the present invention. A wiper assembly 41 comprises a first tiered beam 42 coupled to a pair of secondary beams 43 which in turn are coupled to a wiper blade carrier 47 along with a wiper blade 45. Thus, a load F applied to the first tiered beam 42 is distributed through the second tiered beams 43 to the carrier 47.

Respective couplings 46, 48 deform under this load F for distribution purposes and also to achieve consistence with windshield curvature when the assembly 41 is secured to a motor vehicle. The couplings 46, 48 have a substantial crook shape configured to allow rotary deformation about the mountings to respective beams 42, 43 and thus achieve lateral deformation in addition to deformation perpendicular to the blade 45.

Figure 5 illustrates a fifth embodiment of the wiper assembly which substantially combines the features of Figures 1 and 4. Thus, couplings 51, 52, 53 are all substantially in the same plane in order to couple a primary beam 54 to secondary beams 55 which are connected to tertiary beams 56.

In such circumstances, a load force F is presented through the tertiary beams 56 to a wiper blade carrier 57 and so to a wiper blade 58 in order to deform that blade into contact with a windscreen, not shown. The embodiment of Figure 5 combines the advantages of a crook type coupling with all such couplings being in a consistent plane for good load distribution.

It will be appreciated that the consistent feature with regard to all the embodiments of the present invention described above is load distribution along with deformation to accommodate curvature of a motor vehicle windscreen. Common features between all embodiments are at least a first or primary beam tier 2 is normally constituted by a single tiered beam 2; 22; 32; 42 to which is secured a second beam tier for load distribution purposes. The respective first beam tier and second beam tier being coupled together using coupling means to allow lateral in addition to vertical displacement of the assembly in order to accommodate windscreen curvature for consistent abutment presentation of a wiper blade 5; 25; 35; 45 to that windscreen.

Cascade distribution of load force F through tiered beams is provided with an integral structure for lateral deformation for appropriate presentation of a wiper blade to a windscreen. Provision of hinge or rotary type couplings is illustrated in International Patent Publication No. W098101329 and others is known, but it will be appreciated by those skilled in the art that such fixed point type coupling means present a significant limitation upon the ability of a wiper assembly to accommodate lateral deformation.

Furthermore, such pivot or hinge type couplings can act as relatively hard points in presentation of load force F to a windscreen through a wiper blade within resultant diminution in wiper function. The present invention, by providing respective couplings between tiered beams of a wiper assembly that include or allow deformation both perpendicular and lateral to the wiper blade, significantly enhance both load distribution and presentation of that wiper blade to a motor vehicle windscreen. Thus, in accordance with the present invention the coupling means typically include undulations or Al correlations or up to a 180' tour/meander between mounting positions or has an eccentric shape to provide through compound component analysis axial differential deformation for the coupling means or through appropriate configuration, ie. perpendicular or the like, presentation of individual component elements of the coupling means to provide both lateral and vertical deformation to accommodate windscreen curvature. Typically, a combination of rotary hinge type coupling and lateral couplings will be provided within each wiper assembly.

By providing a wiper assembly which can be made as an integral 10 construction and from a plastics material, it will be appreciated that such wiper assemblies will be cheaper to manufacture and so can be used as a disposable item for initial dispatch of newly manufactured motor vehicles. However, if suitable materials are used, the wiper assembly may be suitable for longer term conventional duty.

As with most integrally moulded components, it will be appreciated that specific dimensions for respective tiered beams and couplings win be determined by specific operational requirements. However, within the general context of the above description, it will be appreciated that there will typically be a differential in the dimension and thickness and/or material type between respective tiered beams and couplings therebetween. Furthermore, normally the wiper blade win be of a conventional rubber type used within traditional motor vehicle windscreen wiper assemblies and this wiper blade will be incorporated in a two-part moulding operation conventionally known to those skilled in the art. Similarly, clip mountings for force application or coupling to the wiper assembly can be incorporated as part of the moulding to allow coupling to existing motor vehicle wiper arms, etc.

Claims

CLAI1US

1. A wiper assembly for a motor vehicle, the assembly comprising a plurality tiered beams coupled together in a hinged cascade to present, in use, a wiper blade arrangement to a windscreen of a motor vehicle, said wiper blade arrangement and said tiered beams being arranged in at least two tiers with ends of one tiered beam in a first beam tier coupled through coupling means to intermediate portions in tiered beams of a second beam tier, the assembly characterised in that the coupling means between said second beam tier and said first beam tier or said wiper blade arrangement is configured to allow significant lateral movement in the axis of the wiper blade arrangement along with huge movement thereabout to facilitate more even load presentation therethrough and for consistency with any curvature of a motor vehicle windscreen.

2. An assembly as claimed in Claim 1, wherein the wiper assembly includes load application means secured intermediate the first beam tier.

3. An assembly as claimed in Claim 1 or Claim 2, wherein the coupling means comprises an undulating or corrugated component.

An assembly as claimed in Claim 1 or Claim 2, wherein the coupling means includes a 180' tour/meander between respective mountings upon tiered beams or the wiper blade arrangement.

5. An assembly as claimed in Claim 1 or Claim 2, wherein the coupling means has an eccentric shape to provide differential axial deformation for that coupling means within the wiper assembly.

6. An assembly as claimed in Claim 1 or Claim 2, wherein the coupling means includes respective loops or bends arranged in a perpendicular relationship with respect to each other in order to provide respective axially perpendicular deformations for the coupling means.

An assembly as claimed in any preceding claim, wherein the coupling means within the assembly is substantially within the same plane.

8. A wiper assembly as claimed in any preceding claim, wherein the assembly is formed from an integral combination of tiered beams and coupling means made from a plastics material.

9. An assembly as claimed in any preceding claim, wherein the assembly comprises one primary tiered beam forming the first beam tier coupled to two secondary tiered beams forming the second beam tier and coupled to said secondary tiered beams are four tertlar.v tiered beams upon which a wiper blade arrangement is secured, the whole assembly having coupling means between respective tiered beams.

10. A wiper assembly substantially as hereinbefore described with reference to Figure 1.

11. A wiper assembly substantially as hereinbefore described with reference to Figure 2.

12. A wiper assembly substantially as hereinbefore described with reference to Figure 3.

13. A wiper assembly substantially as hereinbefore described with reference to Figure 4.

14. A motor vehicle including a wiper assembly as claimed in any preceding claim.

15. A method of making a wiper assembly as claimed in any preceding claim comprising integrally moulding a plurality of tiered beams together with coupling means therebetween within a mould.

16. A method as claimed in Claim 15, wherein a wiper blade is located with the mould prior to moulding the plurality of tiered beams together to form the wiper assembly.

17. A method as claimed in Claim 15 or 16, a plurality of wiper assemblies are formed by moulding or extending a preform in a mould which is subsequently sliced in order to provide respective wiper assemblies from each slice.

18. A method as claimed in any of Claims 15, 16 or 17, wherein force application or coupling means is moulded into the wiper assembly by insertion into the mould prior to moulding of the tiered beams to form the wiper assembly.