Brushing – scrubbing – and general cleaning – Attachments – Optical-member-attachable cleaner
Patent
1988-12-20
1991-02-12
Stinson, Frankie L.
Brushing, scrubbing, and general cleaning
Attachments
Optical-member-attachable cleaner
1525033, B60S 134
Patent
active
049912518
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to a wiper arm.
BACKGROUND OF THE INVENTION
A wiper arm of this kind is known from the German patent specification No. 35 23 546. This known wiper arm has a two-armed lever mounted on the fastening member and pivotable about a shaft mounted perpendicularly to the longitudinal direction of the wiper arm. An adjusting member mounted within the wiper shaft acts upon the first arm of the lever which is closest to the wiper shaft. A pressure spring connects a link and a wiper rod projecting into the link with the second arm of the lever. In order to regulate the contact pressure between a wiper blade attached to the wiper rod and the windshield, the lever can be continuously adjusted between two positions. Because of the possibility of adjusting the contact pressure this known wiper arm is suitable for windshield wiper systems of motor vehicles which can be driven very rapidly. If the vehicle speed is very high the contact pressure must be higher than usual, so that the wiper blade mounted on the wiper rod cannot be lifted off the windshield by the slip stream.
In this known wiper arm, to replace the wiper blade the link can be rotated about an axle into a replacement position, in which the line of application of the pressure spring between the wiper rod and the second lever arm lies beyond the dead center line of the spring relative to an articulated axle between fastening member and link. The lever is fully extended in the replacement position, and the link is offset from its operating position by an angle of about 85.degree.. Such a large angle is unfavourable for various reasons. On the one hand this known wiper arm cannot be used in windshield wiper systems in which the wiper arm is covered by body portions in the area of the fastening member, particularly in the area of the link. On the other hand the link and the parts connected with it (wiper rod and/or wiper blade) can impact the windshield with great force if the link is moved by hand from the tilted position into the parking position and is erroneously released too early. The window shield or the wiper arm can be heavily damaged as a result of such an impact.
SUMMARY OF THE INVENTION
It is the object of the present invention to improve upon the unknown wiper arm by providing a stable replacement position with a tilting angle as small as possible.
According to the present invention this problem is solved by variable displacement of the second point of application of the pressure spring relative to the articulated axle between the fastening member and the link. As compared to usual constructions having a non-displaceable point of application the tilting angle of the present invention is diminished, because by displacement of the second point of application the perpendicular spacing between articulated axle and the line of application of the pressure spring is reduced.
As in the known wiper arm, the second point of application of the pressure spring can be displaced during operation by moving the lever. For this purpose, an adjusting drive mechanism must be used. However, in addition to displacement by movement of the lever, the second point of application of the present invention may be displaced linearly along a guide rail traversing the longitudinal axis of the lever.
In principle the second point of application of the pressure spring need not be displaced much. For example it can be displaced so far that, the line of application of the pressure spring extends above its dead center line opposite the articulated axle between fastening member and link.
By linear displacement of the second point of application of the pressure spring further extension of the spring and thus a load on the spring that results in a premature reduction of spring performance can be avoided.
In principle the displacement of the second point of application of the pressure spring could be effected by guiding the point of application within an oblong hole worked into the lever. However, with an accumulation of dirt, ice or rust in the
REFERENCES:
patent: 2736053 (1956-02-01), Oishei et al.
patent: 4370774 (1983-02-01), Bienert et al.
patent: 4698872 (1987-10-01), Watanabe
patent: 4736484 (1988-04-01), Bauer et al.
Egner-Walter Bruno
Schmid Eckhardt
Scholl Wolfgang
Lewis J. Gordon
Seitter Robert P.
Stinson Frankie L.
SWF Auto-Electric GmbH
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