GB2300802A

GB2300802A - Wiper blade assemblies

Info

Publication number: GB2300802A
Application number: GB9610006A
Authority: GB
Inventors: Cedric Sheng Kao Charng
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-05-15
Filing date: 1996-05-14
Publication date: 1996-11-20
Anticipated expiration: 2016-05-14
Also published as: DE19619832A1; GB9509802D0; GB2300802B; DE19619832C2; FR2734225A1; FR2734225B1; GB9610006D0

Description

1 WIPER BLADE ASSEMBLIES The present invention relates t 0 assemblies,

typically of the type used windscreen wipers on motor vehicles.

2300802 wiper blade for mounting A conventional single blade wiper assembly comprises a primary yoke for attachment to a wiper arm, two secondary yokes pivotally attached to opposite ends of the primary yoke, and a separate tertiary yoke pivc:ia-'ly attached tc one, usually the outermost one, of the two free ends cf: each secondary yoke. Claws for mountinc: a wiper blade are provided at the ends of the tertiary yokes, and at the ends of the secondary yokes not occupied by the tertiary blades. There is thus provided a flexible six point mounting for the wiper blade, which affords a reasonable degree of contact between the wiper blade and the windscreen, at least in calm conditions when the vehicle is stationary or travelling at I Slow s-r-)eed.

is Dual wiper blade assemblies are also known for mounting a pair of winer blades. Typically a known dual wiper blade assembly comprises a primary yoke, one or two secondary yokes pivotally attached to each end of the primary yoke and a separate tertiary yoke articulated to one of the two ends of each secondary yoke. The free ends c.-': each cf: the secondary and tertiary yokes are provided with claws for mounting a pair c..: generally parallel wiper blades.

A problem arises with known wiper blade assemblies, however, an (uiDwar-whe-. the vehc'e is travelling forwards, creating a---flow over the w4ndscreen, since the wi er _ p blade assembly tends to lift away from, the windscreen on its downward stroke. When the vehicle is travelling at speed, the problem, is exacerbated.

The invention seeks to provide an i mproved wiper blade EIAú) ORONAL - 2 assembly, and in a broad aspect provides a windscreen wiper blade assembly comprising at least a primary yoke and a pair of secondary yokes articulated thereto, the primary yoke and/or the secondary yokes being provided with at least one wind-deflecting surface, oriented in relation to the direction of motion of the vehicle so that when said vehicle is moving to create air flow over the windscreen, air is deflected by said surface or surfaces to produce a force tending to urge the wiper blade assem.bly towards the windscreen of the vehicle.

As mentioned above, the principal pr-'--'-em with windlift of the wipe.blade from the windscreen occurs on the downward stroke of the wiper. The or each deflector 0 fore consist of or include surface may there a surface is element which slopes downwardly towards (.L e. - norperpendicular to) the windscreen of the vehicle, when the wiper blade assembly is mounted thereon in a generally horizontal position. This may be accomplished by either a curved or a flat surface, as will be explained more fully below.

in some nreferred embodiments, deflecticn surfaces are provided by curved portions of the outer profile of the assembiv. For example, a hollowed out or indented portion may be provided on the outer surface of the assembly (i.e.

the surface facing in the direction of motion of the vehicle). Preferably the conformation of the hollowed out portion is effective to deflect air from a path generally perpendicular to the outer surface of the assembly (which will be the predominant direction of incidence of air flowing over the windscreen during forward movement of the vehicle) to a --7-rec-.-Jon generally parallel.--o said outer surface. E',7 sucl. means, a major part (and preferably substantially the w-c)le) cf the momentum c).-': the air flow incident u-oon the deflection surface is transferred to the wiper blade assembl%, thus maximising the biasing force on the assembly towards the windscreen.

BAD OR]GiNAL 3 - In a specific embodiment described in detail below, the hollowed out portion intersects the outer surface of the assembly at a generally arcuate or parabolic rim, and is formed by walls which descend relatively steeply from the central portion of the rim, and become progressively shallower away from the central portion, and towards the end portions of the rim. In the described embodiment, there are two hollowed out portions, one disposed on each secondary yoke at the vicinity at which the secondary yoke is articulated to the primary yoke, and oriented inwardly towards a central portion of the primary yoke so that incident air is deflected generally in that direction. The holi.owed out portions could a'- lternaively, or add-it-ic,--=-'!Lv, be positioned on the pr--mary yoke, preferably -'- the vicinity of the secondary yoke mounting. An advanrace of such positioning is that even pressure is applied to the limbs of -the secondary yokes. To assist further in evenly distributina the biasing force and improvinc the conformability of the wi,,)er blade with the w-ndsc:--=-en, tertiary yokes are articulated to the inner limbs of the secondary yokes, rather than the outer limbs.

Alternatively or additionaily, deflecting surfa::e(s) may be provided by one or more elongate members or w.ngs extending generally parallel to the main axis of the wiper blade assembly. Preferably, four such wings are provided in total, arranged in two pairs, one pair being associated with each limb of the primary yoke. Each such pair comprises Individual wings disposed substantially parallel to each other on opposite lateral sides of the limb.

Conveniently, the wings are mounted on the secondary yokes, and arranged to lie alongside the primary yoke when the secondary yokes are mounted thereto. The deflection surfaces of the wings may be planar or curved, but in e-Jiher event are preferably oriented inwardly towards the central axis of the primary yoke.

In another alternative arrangement, a defleciion surface is provided by a side wall of a slot passing through BAD ORIGINAL 4;,J t-; 4 the primary yoke, the slot providing a through passage for air, oriented generally in the direction of travel of the vehicle. A deflection surface is provided by the slot wall positioned on the upper side of the slot, when the wiper assembly is mounted to the vehicle in a generally horizontal parked position. Such a side wall is in.71ineed with respect to an axis perpendicular to the outer surf-ace of the primary yoke, so as to slope downwardly in a dire::::ion towards the windscreen of the vehicle. The lower wall of the slot may extend generally parallel to an axis perpendicular to the outer surface of the primary yoke, or -ray be inclined thereto in a direction opposite to the Inclination of the upper wall. It is preferred that there be some degree of inclination of the lower wall, but that this should usually be less than the degree of inclination of ihe upper wall. The slot is therefore tapered from the outer surface of the primarv yoke towards the inner surface. A p'urality of similar slots may be provided, preferably in the primary yoke, but optionally also (or alterna7:--'vely) in the secondary yokes. When slots are provided in conjunction with wings, the wings may be disposed so as to channel air into the slots.

The above described features can be used individually or in combination. In each case one or more surfaces are provided which slope downwardly towards the windscreen of the veh-'ic"le. gy this means, air flowing over a windscreen imninaes on the deflection surface and nroduces a reaction force directed Qenerally upwardly towards the windscreen. During -the downward stroke of the wiper, the downward force provided by the driving motor counteracts the upward component of the reaction force, and the wiper assembly is forced downwards while being biased towards the windscreen to discourage or prevent wind lift.

It will be noted in the arrangements described above which ave inwardly directed hollowed out portions, symmetrical arrangements of wings, or slots having inclined bottom walls, that in addition to the described deflection 1 i E34D ORIGINAt surfaces which slope downwardly towards the windscreen, surfaces are also provided which slope upwardly towards the windscreen. Such surfaces help to bias the wiper assembly towards the windscreen during the upward stroke of the wiper, and are also of use in wipers which describe a full semi-circular path, half of which involves a downstroke with the assembly effectively inverted.

The invention is hereinafter de-scribed by way of example only, with reference to the accompanying drawings in 10 which: - Figure 1. is a perspective view of an embodiment of wiper blade assembly according to the invention; Fiaure 2. is embodiment; a side elevation of the Figure 1 is Figure 3. is a top plan of the Figure 1 embodiment; Figure 4. is an exploded view of the components of the Figure 1_ embodiment; Fiaure 5. is an enlarged perspective view of a portion of the Figure 1 embodJment, in the vicinity of a mounting of 20 a secondary yoke to the primary yoke; and 3.

Ficure 6. is an sectional view along line A-A of Figure FlIgure 1 shows an embodiment of wiper blade assembly of the double blade type, but the principles of the invention are also applicable to assemblies carrying a single blade. The Figure 1 apparatus comprises a primary yoke 6, to which are attached two secondary yokes 7 by pivotal attachment means 62/75. lertiary yokes 8 are pivotally mounted on the inner arms of yokes 7 by pivotal attachment means 76/83. Wiper blades 5 comprising wiper rubbers received in backing strips are held by claws 71 and 81 provided respectively on BAD ORIGINA,, "j L_ _ZW) the secondary and tertiary yokes.

As will be seen more clearly from Figure 5, the secondary yokes 7 are provided with hollowed out or indented portions 73, which serve to deflect impinging air in the direction shown by the arrows in Figure 5 and Figure 2, when the wiper blade assembly is placed in a head wind, f or example created by the f orward movement of the vehicle. When the wiper blade assembly is in motion in a downward stroke, the upper wall of the hollowed out portion 73 constitutes a deflection surface for impinging air, which produces a reaction force in the wiper blade assembly, tending to bias it towards the windscreen.

The secondary yokes 7 are also provided with elongate wings 74 which extend towards the central portion of the primary yoke 6 from a position in the general vicinIty of the point of mounting of secondary yokes 7 to primary yoke 6. Wings 74 provide deflection surfaces which slope inwardly in a direction towards the windscreen of the vehicle. The wings illustrated have curved surfaces, but the surfaces could equally well be flat. When the wiper blade assembly is in motion in a downward stroke, the upper wings present faces which slope generally downwardly towards the windscreen, and which when impinged upon by oncoming air tend to produce a force biasing the wiper blade assembly towards the windscreen. In an alternative arrangement, the wings slope outwardly away from the primary yoke 6 instead of sloping inwardly towards the primary yoke.

Two posts 63 (one only shown) depend from the underside of the primary yoke 6 in a position near the wings 74 on the side over which the wiper arm extends. The wiper blade assembly is preferably made form plastics material having a degree of resilience so that the wiper rubbers conform to the shape of the windscreen under the action of this arm. The posts 63 abut the upper surface of the secondary yoke 7 and prevent the tips of the wings 74 from rising too high above the primary yoke 6 and interfering with the wiper arm, - 7 as might otherwise occur during flexing of the wiper blade assembly.

Primary yoke 6 is also provided with slots 61, which provide through passages for air. The inner profile of a typical slot 61 is shown in Figure 6, from which it will be seen that the right hand wall as illustrated (which constitutes the uppermost wall of the slot when the wiper blade assembly is mounted on a vehicle in a parked condition) is inclined to an axis perpendicular to the outer surface of the wiper blade assembly, so that it presents a face which slopes downwardly towards the windscreen. The left hand wall of the slot (which constitutes the lowermost wall when the wiper blade assembly is parked) is also inclined to the aforesaid axis, in the opposite direction to the right hand wall, and to a lesser extent. When the wiper blade assembly is in motion in a downward stroke, air from a headwind enters slots 61 and impinges upon the uppermost walls thereof, producing a reaction force tending to bias the wiper blade assembly towards the windscreen.

The effect of the invention is enhanced in the illustrated embodiment by the provision of fins 72, which also serve to create the biasing force towards the windscreen when the vehicle is in motion.

i BAD ORIGINAL J0 j 8

Claims

1. A windscreen wiper blade assembly comprising at least a primary yoke and a pair of secondary yokes articulated thereto, characterised in that the primary yoke and/or the secondary yokes are provided with at least one wind-deflecting surface, oriented in relation to the direction of motion of the vehicle so that when said vehicle is moving to create air flow over the windscreen, air is deflected by said surface or surfaces tc) produce a force tending to urge the wiper blade assembly towards the windscreen of the vehicle.

2. An assembly according to claim 1, characterised in that the or each deflection surface comprises a surface element which slopes downwardly towards the windscreen of the vehicle, when the wiper blade assembly is mounted thereon in a generally horizontal position.

3. An assembly according to claim 1 or 2, characterised in that the or each deflection surface is provided by a curved portion of the outer profile of the assembly.

4. An assembly according to claim 3, characterised in that a hollowed out or indented portion is provided on the outer surface of the assembly

5. An assembly according to claim 4, characterised in that the conformation of the hollowed out portion is effective to deflect air from a path generally perpendicular to the outer surface of the assembly to a direction generally parallel to said outer surface, such that a major part of the momentum of the air flow incident upon the deflection surface is transferred to the wiper blade assembly.

6. An assembly according to claim 4 or 5, characterised in that the hollowed out portion intersects the outer surface of the assembly at a generally arcuate or parabolic rim, and is formed by walls which descend relatively steeply from the central portion of the rim, and become progressively shallower away from the central portion, and towards the end portions of the rim.

7. An assemblly according to any preceding Claim, characterised in that tertiary yokes are articulated to the 10 inner limbs of the secondary yokes.

8. An assembly according to any preceding claim, characterised in that at least one deflection surface is provided an elongate member or wing extending generally parallel to the main axis of the wiper blade assembly.

9. An assembly according to claim 8, characterised in that f our such wings are provided, arranged in two pairs, one pair being associated with each limb of the primary yoke and each such pair comprising individual wings disposed substantially parallel to each other on opposite lateral 20 sides of the limb.

10. An assembly according to claim 8 or 9 characterised in that the deflection surface of the or each wing is oriented inwardly towards the central axis of the primary yoke.

"

1 1.

An assembly according to any preceding claim, characterised in that at least one deflection sur-face is provided in a slot passing through the primary yoke and/or secondary yokes, which slot provides a through passage for air, oriented generally in the direction of travel of the vehicle, the or each deflection surface being provided by the slot wall positioned on the upper side of the slot, when the wiper assembly is mounted to the vehicle in a generally horizontal parked position and said side wall being inclined with respect to an axis perpendicular to the outer surface of the primary yoke, so as to slope downwardly in a BAD ORiGINAlL direction towards the windscreen of the vehicle.

12. An assembly according to claim 11, characterised in that a plurality of said slots are provided.

13. A windscreen wiper blade assembly, substantially as hereinbef ore described with reference to the accompanying drawings.