Brushing – scrubbing – and general cleaning – Attachments – Optical-member-attachable cleaner
Reexamination Certificate
2002-06-26
2004-08-10
Jones, Deborah (Department: 1775)
Brushing, scrubbing, and general cleaning
Attachments
Optical-member-attachable cleaner
C015S250230, C015S250300, C015S250310, C015S250340
Reexamination Certificate
active
06772470
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a four-jointed wiper arm assembly.
BACKGROUND INFORMATION
Wiper systems for motor vehicles having multiple windshield wipers are attached to the vehicle body using their wiper bearings directly or indirectly via a plate. A wiper motor with a built-in gearing drives, via a crank and joint rods, further cranks which are rigidly connected to a driveshaft for each windshield wiper.
Furthermore, it is possible that the output shaft of the wiper motor drives a four-jointed wiper arm assembly. This wiper arm assembly has a pivotable drive lever which sits on a drive axis and is flexibly connected to a link rod via a coupling element. The other end of the link rod sits on a fixed axis. Since the link rods are long, they require a relatively large amount of installation space. A fixing part of a wiper arm, to which a joint part of the wiper arm is fixed via a swing-down joint, is molded onto the coupling element. The drive lever can be driven directly by an output shaft of the wiper motor or via a crank and joint rods. The kinematics of the four-jointed wiper arm assembly causes a combined stroke-pivot movement of the windshield wiper. In this manner, the windshield wiper, the driveshaft of which is positioned more toward the center of the windshield, can follow the angular contour of a windshield better when the windshield wipers are synchronized, and this device is therefore frequently used in wiper systems to increase the field of view and comfort on the passenger side.
The wiping range of a windshield wiper is delimited by a parking position and a return position. The windshield wiper moves out from the parking position, which frequently is in the lower location in a hood gap between the engine hood and the windshield, upward to the return position and then back again.
The windshield wiper has a wiper arm, including the fixing part and a joint part coupled to it, onto which a wiper rod is coupled or molded. The free end of the wiper rod is flexibly connected to a wiper blade, a wiper strip of which with its wiper lip is moved over the windshield between the parking position and the return position during the pivot movement.
A wiper blade for cleaning curved windshields of motor vehicles is described in German Published Patent Application No. 36 21 233. In order to achieve good wiping results on a flat windshield, the wiper blade of a windshield wiper must be positioned so that its longitudinal central plane is perpendicular to the windshield when the wiper blade is unloaded, and a wiper lip molded on the wiper strip only touches the windshield surface. In spherically curved vehicle windshields, the slope of this longitudinal central plane to the windshield surface changes over the entire wiped area. Furthermore, the slope of the longitudinal central plane also changes in the longitudinal direction of the wiper blade. The optimum alignment described for a flat windshield can only be achieved during the wiper operation for spherically curved vehicle windshields at certain points and traveling in the longitudinal direction of the wiper blade. In this case, the deviations from the perpendiculars or the normals to the vehicle windshield, which are measured in angular degrees and are called perpendicular deviations or perpendicular errors, are greater in the more strongly curved side regions of the vehicle windshield than in the flat central regions. The flexibility of the wiper squeegee can only partially compensate for the perpendicular deviation.
In practice, the necessary setting angle of the wiper blade relative to the windshield and thus the perpendicular error is usually produced by slanting the output axes of the wiper linkage. The wiper blade therefore assumes a desired position which deviates from a perpendicular position relative to the vehicle windshield. Since wiper systems are characterized by a large length/width ratio, a great sensitivity of the angular position of the output axes and thus of the perpendicular error of the wiper blade results, particularly in the parking position. The manufacturing tolerances of the individual, numerous components of the windshield wiper and its drive are low, however, the sum of the tolerances, combined with those of the attachment to the vehicle body and of the body itself, is so large that an optimum setting angle is not ensured in mass production. To compensate for the manufacturing tolerances, the longitudinal central plane of the windshield wiper to the vehicle windshield is therefore set during assembly by setting the wiper arm so that the desired perpendicular error is achieved. The setting in the parking position, which is to allow the greatest possible bandwidth in regard to the setting angle, must not, however, lead to significant deviations in the return position of the windshield wiper.
A shaft-hub connection of a windshield wiper in which, in the connection region, the driveshaft has an offset and a cross-section which deviates from the circular, and is in particular polygonal, is described in German Published Patent Application No. 44 28 371. An edge of a recess of the fixing part presses against the offset or an intermediate disk, with the recess conically expanding toward the end of the driveshaft. A matching, conical clamping part, which is pressed by a nut against the fixing part, is inserted into the recess. The clamping part has a passage for the driveshaft, the cross-sectional profile of which corresponds to that of the driveshaft.
A similar shaft-hub connection of a windshield wiper is described in U.S. Pat. No. 3,085,821. The clamping part has a passage for the driveshaft which fits with a cylindrical or conical region of the driveshaft having a knurl and/or a toothed surface. Through the conical connection between the fixing part and the clamping part and, if necessary, through the conical connection between the clamping part and the driveshaft, the toothed surface of the fixing part and of the driveshaft is pressed into the surface of the clamping part, which was as smooth as possible up to this point, and permanently deforms it. For this purpose, the clamping part is made of an elastomer material or a relatively soft non-ferrous metal. In addition to the adhesion, a supporting positive connection is achieved by the many small lateral surfaces of the teeth.
SUMMARY
According to an example embodiment of the present invention, in a parking position of the windshield wiper, the drive lever of a four-jointed wiper arm assembly encloses an angle &agr; of approximately 90° with the coupling element and is adjustable about an adjustment axis which extends approximately parallel to the coupling element and intersects the longitudinal axis of the driveshaft. The coupling element is connected to a link rod via a ball joint. Furthermore, a fixing part, on which a joint part with a wiper rod is coupled via a swing-down joint, of a wiper arm is attached or molded onto the coupling element. A wiper blade is flexibly connected to this wiper rod.
As the drive lever pivots about the adjustment axis, the coupling element is rotated around its longitudinal axis with the fixing part and the desired perpendicular error of the wiper blade is thus set. Setting may be easily performed in the parking position of the windshield wiper. The adjustment range may be +/−3°. This is achieved in addition to the slanting of the two main axes of the drive lever.
The desired perpendicular error of the wiper blade may be freely selected during assembly of the windshield wiper, so that manufacturing tolerances do not negatively influence it. If the drive lever is rotated about the adjustment axis, the height of the coupling element changes. To prevent the four-jointed wiper arm assembly from being tensioned and the movement cycle from being blocked by this, it is possible for the coupling element to include two parts, with the first coupling part being coupled to the drive lever and being connected via a rotary joint, the rotational axis of which extends transverse to the longitudina
Bahta Abraham
Jones Deborah
Kenyon & Kenyon
Robert & Bosch GmbH
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