Brushing – scrubbing – and general cleaning – Attachments – Optical-member-attachable cleaner
Reexamination Certificate
1999-06-11
2001-09-25
Graham, Gary K. (Department: 1744)
Brushing, scrubbing, and general cleaning
Attachments
Optical-member-attachable cleaner
C015S250430
Reexamination Certificate
active
06292974
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a wiper blade for windows of motor vehicles.
In wiper blades the support element is meant to assure the evenest possible distribution of the wiper blade contact pressure on the windows, over the entire swept field swept by the wiper blade. By means of a suitable curvature of the unstressed support element—that is, when the wiper blade is not applied to the wiper blade—the ends of the wiper strip, which in wiper blade operation is pressed entirely against the window, are urged toward the window by the then-stressed support element, even if the radii of curvature of spherically curved vehicle windows differ in every position of the wiper blade. The curvature of the wiper blade must accordingly be somewhat greater than the greatest curvature measured in the swept field of the window to be wiped. The support element thus replaces the complicated support bracket construction, having two spring rails disposed in the wiper strip, of the kind employed in conventional wiper blades.
The invention takes as its point of departure a wiper blade of this type. In a known wiper blade of this type (German Patent DE-PS 12 47 161), the wiper blade, or its support element, which for reasons of distributing the contact pressure protrudes far past the wiper strip in the middle region of the wiper blade, can on the one hand be engaged from below, on the front side facing into the wind, with an attendant buildup of overpressure, by this overpressure. On the other hand, on the back side facing away from the wind, because of the structural form noted above, a considerable negative pressure builds up. Although the wiper blade, which during operation usually executes a pendulum motion, constantly changes its position relative to the oncoming relative wind, even then one of its long sides is always more or less greatly exposed to the wind and is therefore called the front side, while its other long side is accordingly also thought of as the back side. At relatively high vehicle speeds, given the cooperation of these two aforementioned pressures, both of which are oriented counter to the wiper blade contact pressure, this contact pressure is reduced at least enough that proper wiping is no longer possible. Increasing the wiper blade contact pressure against the window at high vehicle speeds could admittedly reduce the severity of this problem, but at lower vehicle speeds, when the liftoff tendency is less, the friction between the wiper blade and the window increases; this leads to undesirable noise buildup and to excessively high stress on the drive components and on the rubber of the wiper.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a wiper blade which avoids the disadvantages of the prior art.
In keeping with these objects, one feature of present invention, resides, briefly stated, in a wiper blade provided with a leading-edge face which extends longitudinally over the wiper blade and substantially parallel to the window and faces into the wind, and which crosswise to its length forms an acute angle with the window.
In the wiper blade of the invention, via the leading-edge face that faces into the wind, a force component aimed at the window is built up, which counteracts the liftoff tendency of the two pressures and thus assures excellent cleaning quality, at least in the region of the swept field swept by the wiper blade, that is, the region that is important to the vehicle's driver. Depending on the size of the leading-edge face and/or on the size of the approach angle &agr;, this auxiliary contact pressure can be adapted to the variable demands that depend on the type of vehicle. It is also advantageous in the arrangement of the invention that as a function of the vehicle speed, the contact pressure rises or falls with this speed. Thus a suitably “high auxiliary contact pressure” is opposed only to the liftoff tendency that occurs at high speed.
A compact wiper strip is obtained if the leading-edge face is disposed on the face of the support element facing away from the window. The auxiliary contact pressure is then distributed not in point form but areally, over the entire length of the wiper blade.
The embodiment of a leading-edge face can advantageously by attained in that it is embodied on a separate, elongated component that is solidly joined to the support element.
A simple structure of such a separate component is obtained in that, seen in cross section, it has at least approximately the shape of a triangle, one side of which contacts the face of the support element facing away from the window, and also that the leading-edge face is embodied on another side of the triangle. In certain cases, it can be advantageous to equip the leading-edge face at least partially with a hollow curvature facing into the wind.
Securing the component to the one side of the support element is achieved economically by a glued connection. So that the distribution of the contact pressure effected by the support element will not be impaired, the component is made from a rubber-elastic material whose hardness is no greater, and is preferably less, than the hardness of the rubber-elastic wiper strip. Advantages in terms of production are attained if the component is made from a suitable plastic.
The length, and the width and height projected in the operating direction of the wiper blade, of the leading-edge face is designed to suit the requirements. In certain cases it is expedient if the leading-edge face extends at least nearly over the entire length of the wiper blade.
Further advantageous refinements and features of the invention are recited in the ensuing description of an exemplary embodiment shown in the accompanying drawing.
REFERENCES:
patent: 3088155 (1963-05-01), Smithers
patent: 3317945 (1967-05-01), Ludwig
patent: 3418679 (1968-12-01), Barth et al.
patent: 3879793 (1975-04-01), Schlegel
patent: 5546627 (1996-08-01), Chen
patent: 1 247 161 (1970-01-01), None
patent: 2311293 (1974-09-01), None
patent: 2336271 (1975-02-01), None
patent: 2440179 (1975-11-01), None
patent: 316114 (1989-05-01), None
patent: 2199302 (1974-04-01), None
patent: 1429820 (1976-03-01), None
Kotlarski Thomas
Leutsch Wolfgang
Merkel Wilfried
Graham Gary K.
Robert & Bosch GmbH
Striker Michael J.
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