GB2247162A - Windshield wipers - Google Patents

Abstract

A windshield wiper mount 20 holds a blade 21 against a windshield. It includes shells 25, 26 hinged at pin 27 comprising a central shaft and flanges 30 and 29 (not shown). A spring 35 mounted on the pin 27 acts to fold the shells 25, 26 so that their ends press against the windshield. Rocker beam 45 with arms 46, 47 rocks around pin 27 and is biassed towards the windshield. There are thus four blade attachment points i.e. at the shell ends and the rocker beam ends. The shells 25, 26 also provide a shield against direct sunlight for the blade 21 as well spoiler tabs 66, 67 to counter lift. <IMAGE>

Description

4 1 WINDSHIELD WIPERS

Field of Invention

This invention relates to windshield wipers.

Backqround of the Invention The wiping of a flat planar windshield to remove water and grime does not involve any special geometrical problems. It is merely necessary to move a straight linear blade along a flat surface.

However, very significant problems arise when the wiper is to wipe along the types of severely bent surfaces used for windshields of automobiles of very stylish or very aerodynamically efficient shapes. When the wiper is near the zenith of its movement, the contact may be anywhere from straight to gently but substantially bent. At its lowest point, it often extends along a very pronounced curve, and in.between these positions the shape of the line contact undergoes changes which often are rather complex.

The art has responded by making the blade quite flexible so it can conform to the windshield surface, 1 2 and to mount it to a support which will press it as closely as possible to the windshield surface, and with a hopefully uniform surface contact.

The conventional arrangement is to provide articulations in the mounting which apply a force to the blade to press it against the windshield at a plurality of points - usually four or more. Then the theory is that the short blade segments between these points will follow the surface of the windshield.

As might be expected, these efforts are ar least partially successful, but they become less effective at high vehicle speeds due to the buffeting and aerodynamic lift of the windstream. Under these circumstances, a single blade often leaves broad streaks of unwiped windshield, just when and where wiping is most needed.

The art has responded with double wipers, using two blades instead of one. It is readily theorized that a second blade may well wipe where the first blade failed. Unfortunately this simplistic solution brings with it new problems.

First, because the wiper assembly must be fitted to an actuator arm which both moves the wiper across the windshield and presses the blades against it, the unit loading on each blade is reduced by half. Thus the ii 1 i 21 i i i i i 1 1 1 i 1 1 1 1 1 i 1 i i 3 efficiency of the individual blade is reduced.

Second, there is a region between the blades in which grime and water is moved back and forth until it either drains out the bottom, or is centrifugally ejected. Of course it continues to be replaced, and there exists between the blades a constant "reservoir" of water and grime for the less-efficient blades to work against.

Even more, because the load on conventional wiper motor is doubled (the drag on wipers having been doubled), the failure rate of these motors is noticeably increased. For that matter, so is the cost of two wiper blades instead of only one.

A single blade wiper with maximum load against the windshield is much to be preferred.

Known existing mounting means for supporting blades with application of force at four or more locations shows a rather pedestrian approach. In one type of device, a rigid housing supports a pair of spring-loaded pivotal beams, each of which is attached at two points to the blade. This device suffers from a lack of accommodation to account for severe changes in windshield shape experienced by the two beams.

4 In another type, the support itself is articulated, and its articulations somehow exert a pressing force against the blade at a plurality of points. It is common for these articulations to be pivotally biased relatively to one another with a coil spring. The problem here is that the force excited by the coil spring is a function of the relative angular position of the articulations. Thus it is less in some positions than in others- usually just when the force is most needed.

It is the object of this invention to provide an articulation with springbiasing means whose bias force does not appreciably decrease when the articulations "fold" toward one another to follow a severely curved contour.

Because snow, mud and slush are also problems, it is an object of this invention to provide a construction which sloughs off such materials, and which tends not to pack up with them.

Wiper blades face severe conditions even when not in use. One of them is aging that occurs when the blade is exposed to sunlight. It is an object of this invention to provide shell means which substantially shield the blades from direct sunlight.

1 i 1 i i i i 1! 1 11 1 i i Yet another problem faced by wiper blades is the need for the blade to wipe on a side respective to its instant direction of motion, and preferably with a favourable angle of attack. Any lifting force which moves the blade away from its preferred angle reduces the effectiveness of the blade. Aerodynamic lifting and turbulent air situations can cause these situations. So can uncompensated drag as the blade moves along the windshield.

It is an object of this invention to provide a shell for supporting the blade whose shape can resist torque caused by the windstream, and which can react with the airstream to supplement the force applied by the mounting arm.

Brief Description of the Invention

A wiper according to this invention includes a mounting comprising a pair of shells hinged together for relative rotary movement around a hinge axis. The hinge axis will normally be at least reasonably parallel to the windshield, that is, parallel to a tangen-t to it.

The mounting is attached to the actuating arm at the hinge, an exerts a force pressing the wiper toward the windshield in a conventional manner.

6 Bias means biases the shells toward a closed position so as to exert a force against a wiper blade at each of the extreme ends.

A rocker arm is pivotably mounted to the hinge with a branch on each side of it. Thus it is forced toward the windshield by the spring force of the actuator arm.

The above provides few points of attachment for a wiper blade, one at the distal end of each shell, and one at each free end of the rocker arm.

According to a preferred but optional feature of the invention, the bias means is a leaf-type spring reacting between the hinge and the shells, which provides a spring bias less sensitive to the angular relationship of the shells than provided by a conventional coil spring.

According to another preferred but optional feature of the invention, the shells provide a substantial shading shield protecting the top and much of the sides of wiper blade from sunlight.

According to yet another preferred but optional feature of the invention, the shells may be aerodynamically shaped to cause a force reaction with the windstream tending to add to the forces holding the 1 1 1 z 0 h f 7 wiper against the windshield, including, if desired, torque connecting surfaces to resist twisting of the mount by the airstream.

The above and other features of this invention will be fully understood from the following detailed description and the accompanying drawings, in which:

Brief Description of the Drawings

Fig. 1 is an axial section of the presentlypreferred embodiment of the invention, taken at line 1-1 in Fig. 2, the structure being symmetrical, and part of one side being deleted for simplicity of disclosure;

Fig. 2 is a bottom view of Fig. 1; Fig. 3 is a view similar to Fig. 1 showing the device in a different position; Fig. 4 is a cross-section of the shell of Fig. 1 only, taken at line 4-4 in Fig. 1; Fig. 5 is an axial cross-section of another embodiment of the invention; Fig. 6 is a bottom view of Fig.5; : i 8 Fig. 7 is a cross-section taken at line 7-7 in Fig.5; Fig. 8 is a cross-section taken at line 8-8 in Fig.5; Fig. 9 is a cross-section taken at line 9-9 in Fig-5; Fig.10 is a top view of another embodiment of the invention, the structure being symmetrical, and part of one side being deleted for simplicity of disclosure;

Fig.11 is a side view of Fig. 10 with the device in one position; and Fig.12 is a view similar to Fig. 11 with the device in a different position.

Detailed Description of the Invention

The presently preferred embodiment of a mount 20 according to the invention is shown in Fig. 1. Its purpose is to hold a conventional wiper blade 21 against a windshield (not shown) and draw it across the windshield under the power of a conventional-oscillating actuator arm carried by the vehicle.

The mount includes a pair of shells 25, 26 which are hinged together by a hinge pin 27. The hinge pin has a central shaft 28 and flanges 29. 30 to hold the shells z i i 1 i 1 i 1 1 k 9 together and enable them to rotate relative to one another around hinge axis 31. In operation, the hinge axis will be as close to parallel as possible to a tangent to the windshield. of course this situation will vary, depending on the geometries of the situation.

A bias spring 35 ("bias means") preferably formed as a leaf spring, has a central portion 36 that bears against the hinge shaft and two arms 37,38 which fit into respective recesses 39,40, in the shells. As shown in Figs. 1 and 3, the effect of the bias means is to tend to "fold" the shells toward one another, thereby tending to press the ends 41,42 of the shells toward the windshield. In the drawings, the end portions of shell 25 have been omitted. They are the mirror image of the end portions of shell 26.

A rocker beam 45 is pivotally mounted to the shaft of the hinge pin. It rocks around the hinge pins, and is biased toward the windshield by force exerted on the hinge pin by the actuator arm. The rocket beam has arms 46, 47 on opposite sides of the hinge pin.

This construction provides four points of attachment for the wiper blade, points 50, 51 (point 50 being on the unshown end of shell 25) at the ends of the shells, and 52,53 at the ends of the rocker beam.

1 il !1 This is a fully functional wiper mount which will properly press a flexible blade against a wide range of windshield contours.

As best shown in Figs. 1 and 4, the shells have a longitudinally extending central portion 60 which faces into the airstream. A skirt 61, 62 on each side of the central portion makes a reasonably close approach to the windshield so as to provide as much shielding of the wiper blade from sunlight as possible. of course there must be sufficient clearance that the shell does not contact the windshield, and to permit exit of water and grime. This forms a channel 65 in the shells to receive support means for a wiper blade and much of the wiper blade itself. End flanges such as flange 65a close the inside channels in the shells.

If desired, a spoiler tab 66, 67 can extend longitudinally along the shells at one side thereof. It slopes upwardly and away from the windshield sides of the mount. Its aerodynamic effect is to add force to hold the mount toward the windshield when subjected to an airstream. This counters some of the lift- which the airstream may have given to the mount.

The mount of Fig. 3 shows a gap 70 between the ends of the shell. In the more stylish applications, this is undesirable., Figs. 10-12 shows the use of a flange 71 1k 1 ii i 1 i'i on one shell 72 overhanging part of shell 73 so as to present a more agreeable appearance.

Also, especially for higher velocity installations, additional stability at the tips is sometimes desirable in order to counter the torque exerted by the spoiler. Figs. 10-12 show the use of a skirt tab 75 at the end of the shells. These are configured to apply an additional force on the tips to force them toward the windshield and to counter torque.

As best shown in Figs. 5-9, the central portion 80 of shells 81 and 82 shell may have rounded external surface 83, almost semi-circular, extending in the longitudinal direction. This configuration, while also suitable for forwardly facing windshields, finds its best application as a rear window wiper, because it reduces the effects of turbulence on it. It holds to the surface better, and sheds mud, ice and snow.

The term "windshield" as used herein includes any surface exposed to airstreams generated by movement of the vehicle. This includes not only the forwardlyfacing windshield, but also rear shields such as rear windows, and windows on hatchbacks or rear doors, for example.

The use of a leaf spring also offers advantages in 12 that its ends which bear against the plastic shell material have a substantial bearing area. There results much less long-term damage to the shell material, compared with the thin-wire contact made by the ends of a coil spring. However, coil springs are included herein within the definition of "bias means".

The shells can be made of a slick-surfaced plastic, for example nylon, which tends to shed snow, mud and ice. Also importantly, it can readily be molded to shapes which are attractive and efficient. The concept of using a shell enables a whole new field of styling and performance concepts to be employed.

This invention is not to be limited by the embodiments shown in the drawings and described in the description, which is given by way of example and not of limitation, but only in accordance with the scope of the appended claims.

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Claims (8)

CLAIMS:

1. A mount for supporting a windshield wiper blade comprising: a first and a second shell; hinge means hingedly joining said shells for rotation around a hinge axis, said shells forming an inside channel and having an exterior surface; wiper support means carried by said shells to support said wiper blade disposed in said channel, said exterior surface being so shaped, disposed and arranged to provide a substantial shield against direct sunlight for said support means and for said wiper, and an external surface to react with an airstream and to be visible as a style.

2. A mount according to claim 1 in which said exterior surface includes a spoiler tab extending along each said shell, so disposed and arranged as to press said shell against the windshield when reacted on by an airstream.

3. A mount according to claim 2 in which a trim skirt is formed to each said shell on its side opposite from said spoiler to counteract torque caused by said spoiler.

4. A mount according to claim 1, 2 or 3 in which a flange on one of said shells projects over the other said shell to cover the region where a hinge pin constituting said hinge means is located.

14

5.

A mount according to any preceding claim in which bias means biases said shells towards a closed position.

6. A mount according to claim 5 in which said bias means comprises a leaf spring opposed between a hinge pin constituting said hinge means and said shells.

7. A mount according to any one preceding claim in which a rocker beam is disposed in said channel and hinged to a hinge pin constituting said hinge means, said rocker beam having a pair of arms whereby a wiper blade can be mounted to both of said arms and to the free ends of the shells to force against a windshield.

8. A mount according to any one preceding claim in which said shells are rounded in lateral cross-section, the better to resist accumulation of mud, ice and snow.

Published 1992 at The Patent Office, Concept House, Cardiff Road. Newport, Gwent NP9 1 RH. Further copies mav be obtained from Sales Branch, Unit 6. Nine Mile Point. Cwmflinfach. Cross Keys, Newport, NPI. 7HZ. Printed by Multiplex techniques ltd. St Mary Cray. Kent.

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