Title of Invention

WIPER ARM

Abstract

The invention proceeds from a wiper arm having a hinged wiper blade and a fastening part (10) for fastening to a driveshaft (12) by the latter being inserted through a widening depression (38) in the fastening part (10) and a screw nut (44) clamping the fastening part(10) to the driveshaft (12) against a bearing surface (30) via a clamping part (40, 50) which is matched to the depression (38). It is proposed that the contact surface (66) between the clamping part (40, 50) and the fastening part (10) forms part of the surface of a sphere, and the bearing surface (30) forms part of a circumferential surface of a cylider whose cylinder axis (32) runs through the sphere central point (36) and parallel to the longitudinal direction (34) of the wiper blade.

Full Text

Wiper Arm Prior Art The invention proceeds from a wiper arm in accordance with the preamble of claim 1. Known wipers have a wiper arm constructed from a fastening part and a hinge part which is coupled thereto via a swing-down hinge and has a wiper rod. A hook-shaped end of the wiper rod grips into a hook-in casing of a wiper blade, which casing is formed by two side walls of a central bracket, and the said end comprises a connecting part together with a hinge bolt. The hinge which is formed in such a manner guides the wiper blade during the pivoting movement over the vehicle window/lens glass. The wiper blade has a generally multi-sectioned supporting-bracket system with secondary brackets which are coupled to the central bracket and at least some of which, by means of claws at their ends, hold a wiper strip to its headpiece. The multi-sectioned supporting-bracket system and spring rails inserted into the headpiece enable the wiper strip to be adapted during wiping, with a uniform bearing pressure, to a curved windscreen. For this purpose, a tension spring pre-tensions the swing-down hinge. Wipers of this type are disclosed, for example, in DE 37 44 237 Al. In simplified designs, secondary brackets, which are also called intermediate brackets and claw-type brackets, can be omitted. In the simplest case, the central bracket itself has claws by which it holds the wiper strip. The wiper arm is connected via its fastening part fixedly, but detachably, to a driveshaft. The driveshaft protrudes out of the vehicle body and at its free shaft end has an outer cone which interacts with an inner cone on the fastening part by a screw nut pressing the conical parts firmly together. For a good wiping result and in order to avoid rattling, it is important for the wiper strip together with its wiper lip to be guided over the vehicle window/lens glass at a certain positioning angle. Although the manufacturing tolerances of the numerous individual components of the wiper and its drive are small, the sum of the tolerances together with those associated with the fastening to the vehicle body and with the latter itself is so large that an optimum positioning angle is not ensured in series production. While the wiper systems are readily aligned transversely with respect to the vehicle direction because of their large-length/width ratio, there is poor alignment of especially in the longitudinal direction of the vehicle. DE 44 28 371 Al discloses a shaft-hub connection for a wiper, in which in the connecting region the driveshaft has a cross section which deviates from the circular form and in particular is polygonal, and has a shoulder. The fastening part bears with a lip of a recess against the shoulder or an intermediate washer, the recess widening conically towards the end of the driveshaft. A fitting, conical clamping part is inserted into the recess and is pressed against the fastening part by means of a screw nut. The clamping part has a passage for the driveshaft, the cross-sectional profile of which passage corresponds to that of the driveshaft. us 3 085 821 discloses a shaft-hub connection for a wiper. The fastening part bears with a lip of a recess against a shoulder of the driveshaft or against an intermediate washer, the recess widening conically towards the end of the driveshaft. A fitting, conical clamping part is inserted into the recess and is pressed against the fastening part by means of a screw nut. The clamping part has a passage for the driveshaft, the said passage being suitable for a cylindrical or conical region of the driveshaft, which has knurling or a serrated surface. By means of the conical connection between the fastening part and the clamping part, and optionally by means of the conical connection between the clamping part and the driveshaft, the serrated surface of the fastening part and of the driveshaft is pressed into the surface of the clamping part, which surface is largely smooth up to this point, and permanently deforms the said surface. For this purpose, the clamping part consists of an elastomeric material or of a relatively soft non-ferrous metal. In addition to a frictional connection, a supporting interlocking connection is obtained by many small side surfaces of the serrations. Advantages of the invention According to the invention, the contact surface between the clamping part and the fastening part forms part of the surface of a sphere, while the bearing surface forms part of a circumferential surface of a cylinder whose cylinder, axis runs through the central point of the sphere and parallel to the longitudinal direction of the wiper blade. The effect of this is, in a small construction space, a continuous adjustment of the fastening part and therefore of the wiper arm about its longitudinal axis if the bearing surface is smooth. A stepwise adjustment is possible if the bearing surface has a fluting which is parallel to the cylinder axis. The fluting reinforces, by means of an interlocking connection, the frictional connection to the bearing surface. The frictional connection- may also be supported by the bearing surface on at least one of the parts which are to be connected being roughened. The positioning angle of the wiper blade can therefore be selected freely during installation, with the result that manufacturing tolerances do not have a negative effect on it. The height of the wiper arm is determined here by means of the longitudinal axis of the cylinder during the setting. So that the height is not changed, or is only slightly changed by the setting, according to a refinement of the invention, provision is made for the cylinder axis to run at a small distance from the hinge axis of the swing-down hinge, by which the hinge part is coupled to the fastening part, or to intersect the hinge axis. This is because an increasing distance would result in a greater height deviation during an adjustment. The connection between the driveshaft and the fastening part has to be secure and has to be able to transmit large torques. Nevertheless, it must not react sensitively to the tightening torque of the screw connection to the effect that the setting which is selected is unintentionally changed as the screw is being tightened. It is therefore expedient for the cylinder axis of the bearing surface of the fastening part to run through the sphere central point of the contact surface between the clamping part and the fastening part, the cylinder axis advantageously lying within the fastening region of the fastening part. According to a refinement of the invention, it is proposed that the setting angle of the fastening part about the cylinder axis of the bearing surface is restricted by a stop. This avoids the unintentional setting on the vehicle of angles which are completely unusable. The stops enclose the optimum positioning angle, and settings which deviate - from this are possible and, although not optimal, are usable. In a simple manner, the stops are formed by an elongated hole in the fastening part, which hole runs transversely with respect to the cylinder axis and interacts with the driveshaft. The cylindrical bearing surface can be formed directly on the driveshaft, but is expediently molded into a separate supporting washer, which, after installation, is supported against a shoulder of the driveshaft. The supporting washer is guided in a rotatable manner on the driveshaft, so that the longitudinal direction of the fastening part, and therefore the longitudinal direction of the wiper arm, can be rotated about the driveshaft axis and aligned before the torque connection between the clamping part and the screw connection is produced. At the same time, the fastening part can be rotated about the cylinder axis between the two stops - in order to set the positioning angle of the wiper blade with respect to the vehicle window/lens glass. The torque is expediently transmitted by the driveshaft via a non-circular profile, preferably via a profile having a polygonal cross section, to the clamping part which, for its part, transmits it to the fastening part by means of a mainly frictional connection over the spherical contact surface. As a result", the torque is * transmitted to a small extent by means of a secure interlocking connection, while the frictional connection is provided over a larger diameter and can therefore transmit greater torques by smaller contact-pressure forces. The frictional connection can be supported by means of an interlocking connection by the spherical contact surface of the fastening part being roughened or fluted. In this case, the fluting on the clamping part expediently runs at an angle with respect to the fluting on the fastening part, so that the directions intersect and an interlocking connection is produced which acts both in the direction of the torque to be transmitted and in the direction of the adjusting forces, it being possible for some of the flutings to intermesh. The ability of the fluting to deform also enables manufacturing tolerances to be compensated for. According to a refinement of the invention, the clamping part has longitudinally running grooves on its circumference, which grooves end shortly before the larger end surface. The grooves have the effect that the clamping part can be deformed elastically and can thereby be better adapted to the depression in the fastening part. Since the grooves are not drawn right through to the end surface of the clamping part, but end shortly before it, a smooth end surface is maintained. Furthermore, the grooves are protected towards the outside. The elastic effect of the grooves can be increased by them being provided on a clamping part having a polygonal profile and being arranged opposite the edges of the profile. Furthermore, the grooves are expediently combined with annular steps which surround the clamping part and penetrate into a fluting, which runs transversely to them, in the depression in the fastening part. In order to obtain a play-free interlocking connection between the driveshaft and the clamping part, which connection can also easily be detached, provision is made for the polygonal profile of the driveshaft to taper toward the screw nut. Some parts of the connection may already be installed prior to the final installation. For this purpose, use is made, on the one hand, of a securing ring which is made of plastic and fastens the supporting washer in a rotatable manner on the driveshaft, and, on the other hand in a different design, of a plastic clip which secures the supporting washer to the fastening part in a manner allowing it to pivot about the cylinder axis. In this connection, the fastening part has a collar on which the plastic clip is held. Furthermore, the plastic clip can engage by means of projections in recesses in the fastening part. Drawing Further advantages emerge from the following description of the drawing. In the drawing, exemplary embodiments of the invention are illustrated. The drawing, the description and the claims contain numerous features in combination. The expert will expediently also consider the features individually and combine them into meaningful further combinations. In the drawing: Fig. 1 shows, in an exploded illustration, a fastening part of a wiper arm according to the invention, and a wiper bearing. Fig. 2 shows a partial longitudinal section of a variant on an enlarged scale and in an exploded illustration. Fig. 3 shows the design according to fig. 2 in the assembled state. Fig. 4 shows a section corresponding to the line VI-VI in fig. 3, Fig. 5 shows a variant to fig. 2, Fig. 6 shows a clamping part in a perspective illustration. Fig. 7 shows a perspective partial view of a fastening part from above. Fig. 8 shows a perspective partial view of a fastening part from below, and Fig. 9 shows a fastening part in -three different settings. Description of the exemplary embodiments The drawing shows just part of a wiper system having a wiper arm, specifically to the extent necessary for understanding the invention. The wiper arm includes a fastening part 10 which is fastened on a driveshaft 12. The driveshaft 12 is mounted in a bearing housing 14 which has a connecting branch 16 for a wiper carrier (not illustrated in greater detail) and a fastening lug 18 with which the bearing housing 14 is fastened to a vehicle body (not illustrated) . The driveshaft 12 is driven by a wiper motor via a lever mechanism and a crank 20, which is connected fixedly at one end to the driveshaft 12. The free end of the driveshaft 12 has a shoulder 22 and a profile 24 having a polygonal cross section, and also a thread 26 which is connected to the said profile. A supporting washer 28 is threaded onto the free end of the driveshaft 12, the said supporting washer being supported against the shoulder 22, but being guided such that it can be rotated about the driveshaft 12. Molded into the supporting washer 28, towards the fastening part 10, is a concave, cylindrical bearing surface 30 against which a corresponding cylindrical surface 30 of the fastening part 10 bears (fig. 4). t The fastening part 10 has a depression 38 into which a clamping part 40, 50 is inserted. A screw nut 44, which engages in the thread 2 6, clamps the clamping part 40, 50, the fastening part 10 and a supporting washer 28 to the shoulder 22 of the driveshaft 12. The fastening part 10 may be manufactured by die-casting. However, it is expediently formed from sheet metal, the depression 38 being deep-drawn. The cylindrical bearing surface 30 on the fastening part 10 (fig. 8) is aligned in such a manner that its cylinder axis 32 runs in the longitudinal direction 34 of the wiper arm. Furthermore, the contact surface 66 (fig. 7) of the depression 38 in the fastening part 10, and the surface of the clamping part 40, 50 form part of a sphere whose central point 36 lies on the cylinder axis 32. It is therefore possible to rotate the fastening part 10 about the driveshaft 12 prior to it being clamped by the screw nut 44, and therefore to set the wiper arm in its parking position. Furthermore, the fastening part 10 can be pivoted about the cylinder axis 32. Fig, 9 shows that the fastening part 10 can be adjusted, starting from a central position, by a limited amount in opposite adjusting directions 72 and 74. It is expedient here for the cylinder axis 32 and therefore also for the sphere central point 36 to lie in the fastening region 38 of the fastening part. In order to restrict the adjustment, the hole 46 in the fastening part 10 is elongated transversely with respect to the cylinder axis 32, so that it forms a stop on the driveshaft 12 in each of the two adjusting directions 72, 74. A hinge part (not illustrated) is coupled to the free end of the fastening part 10, the hinge axis being • denoted by 70. The cylinder axis 32 expediently intersects the hinge axis 70; in any case, the distance 80 between the cylinder axis 32 and the hinge axis 70 should be selected to be as small as possible, so that only slight height deviations between the vehicle window/lens glass and the hinge arise during the adjustment of the fastening part 10. As can be seen in fig. 9, in spite of a different setting angle a (fig. 4), the central height of the hinge axis 70 does not change. The clamping part 40, 50 has an inner carrier profile 42, 54 which matches the outer profile 24, 52 of the driveshaft 12 and transmits the driving torque from the driveshaft 12 to the clamping part 40, 50 in an interlocking manner. The said profile expediently has a cross section which deviates from the circular form, preferably a polygonal cross section. In order to obtain easier installation and removal and also to obtain freedom from play, the profiles 54 and 52 run conically towards the end of the driveshaft 12. The interlocking connection between the clamping part 40, 50 and the driveshaft 12 enables large torques to be reliably transmitted over a small diameter, while the clearly larger diameter of the outer circumference of the clamping part 40, 50 is suitable for transmitting the driving torque to the fastening part 10 by a frictional connection. In order to be able to transmit larger driving torques, it is expedient to improve the frictional connection between the clamping part 40 and the fastening part 10 by means of a roughened surface or by means of a fluting 68. It is advantageous if the fluting 68 on the fastening part 10 runs transversely with respect to a possible fluting or surface structure of the clamping part 40. For example, the clamping part 40 may have steps 62 on its circumference (fig. 6), which steps work, during the clamping procedure^ into the fluting 68 of the fastening part 10, which fluting runs in the direction of the driveshaft 12, and therefore provide a secure grip. These measures also enable manufacturing tolerances to be compensated for. Because the cylinder axis 32 of the cylindrical bearing surface 30 of the supporting washer 28 runs radially with respect to the driveshaft 12, driving torques which might unintentionally change the setting during operation are not effective in the adjusting direction 72, 74. The bearing surfaces 30 -both on the supporting washer 28 and on the fastening part 10 can be of smooth design so as to obtain a continuous adjustment. With fluting 68 in the direction of the cylinder axis 32, it is possible to change the setting angle a incrementally. So that the clamping part 40, 50 can readily be adapted to the depression 38, the clamping part 40 has grooves 64 running in the longitudinal direction on its circumference, as -a result of which the clamping part 40 is more elastic in the circumferential direction. In order to obtain a continuously smooth end surface 82, it is expedient for the grooves 64 to end shortly before the end surface 82. In combination with a polygonal carrier profile 42, 54, it is expedient to provide the grooves 64 opposite the edges 76 of the carrier profile 42, resulting in greater elasticity. The installation of the fastening part 10 can be facilitated if the supporting washer 28 is connected to another component prior to installation. Use is made to this end of a securing ring 48 (fig. 2) which holds the supporting washer 28 on the driveshaft 12. Another possibility is illustrated in fig. 5, where, according to the left half of the illustration, a plastic clip 60 grips behind a collar 56 of the fastening part 10, or, as the .right side of tlje illustration shows, latches into a corresponding recess 58. The collar 56 and the recess 58 have to be arranged and configured in such a manner that they do not hinder the adjustment of the fastening part 10 about the cylinder axis 32. WE CLAIM; 1. A wiper arm with an articulated wiper blade and fastening part (10) for fastening it to a drive shaft (12) by the latter being plugged through a widening depression (38) of the fastening part (10) and a screw nut (44) fixing the fastening part (10) through a clamping part (40, 50), which is matched to the depression (38), agamst a bearing surface (30) with a drive shaft (12), characterized in that the contact surface (66) between the clamping part (40, 50) and the fastening part (10) forms part of the surface of a sphere and the bearing surface (30) forms part of a circumferential surface of a cylinder, the cylinder axis (32) of which runs through the sphere centre point (36) and parallel to the longitudinal direction (34) of the wiper blade. 2. The wiper arm as claimed in claim, wherein the cylindrical bearing (30) is shaped into a supporting disc (28) which is supported on a shoulder (22) of the drive shaft (12) and can be rotated about the drive shaft (12). 3. The wiper arm as claimed in any one of the preceding claims, wherein the setting angle (a) of the fastening part (10) about the cylinder axis (32) is limited by a stop. 4 The wiper arm as claimed in claim 3, wherein the stop is formed by a hole (46), which is elongate in the adjusting direction (72, 74) in the fastening part (10) with the drive shaft (12). 5. The wiper arm as claimed in any one of the preceding claims, wherein the cylinder axis (32) runs within the fastening region (78) of the fastening part (10). 6. The wiper arm as claimed in any one of the preceding claims, wherein a hinge part is coupled to the fastening part (10) and the cylinder axis (32) runs at a small distance (80) from the hinge axis (70). 7. The wiper arm as claimed in any one of the preceding claims, wherem the fastening part (10) is formed from sheet metal and the depression (38) is deep-drawn. 8. The wiper arm as claimed in any one of the preceding claims, wherem the fastening part (10) and the clamping part (50) are roughened or corrugated on the spherical contact surface (66) in such a manner that the corrugation of the fastenmg part (10) intersects the corrugation of the clamping part (50). 9. The wiper arm as claimed in any one of the preceding claims, wherem the clamping part (40, 50) has annular steps (62) on its circumference. 10. The wiper arm as claimed in any one of the preceding claims, wherein the clamping part (40, 50) is connected to the drive shaft (12) through a profile (24, 52) which deviates in cross section from the circular form. 11. The wiper arm as claimed in claim 10, wherein the profile (24, 52) has a polygonal cross section. 12. The wiper arm as claimed in any one of the preceding claims, wherem the clamping part (40) has grooves (64) running longitudinally on its circumference. 13. The wiper arm as claimed in claim 12, wherein the grooves (64) end shortly before the relatively large end surface (82). 14. The wiper arm as claimed in any one of claims 11 to 13, wherein the grooves (64) lie opposite the edges (76) of the polygonal profile (24, 52). 15. The wiper arm as claimed in any one of claims 11 to 14, wherein the polygonal profile (52) of the drive shaft (12) tapers towards the screw nut (44). 16. The wiper arm as claimed in any one of claims 2 to 15, wherein the supporting disc (28) is fastened rotatably on the drive shaft (12) by a plastic securing ring (48). 17. The wiper arm as claimed in any one of claims 2 to 15, wherein the supporting disc (28) is fastened to the fastening part (10) in a manner such that it can pivot about the cylinder axis (32). 18. The wiper arm as claimed in claim 17, wherein the supporting disc (28) is fastened to the fastening part (10) by means of a plastic clip (60). 19. The wiper arm as claimed in claim 18, wherein the fastemng part (10) has a collar (56) on which the plastic clip (60) is held. 20. The wiper arm as claimed in claim 18, wherein the fastening part (10) has recesses (58) into which the plastic clip (60) snaps. 21. The wiper arm as claimed in any one of the preceding claims, wherein the cylindrical bearing surface (30) of the fastening part (10) and/or of the supporting disc (28) has a corrugation (68) running parallel to the cylinder axis (32).

Documents:

in-pct-2001-0263-che abstract-duplicate.pdf

in-pct-2001-0263-che abstract.jpg

in-pct-2001-0263-che abstract.pdf

in-pct-2001-0263-che claims-duplicate.pdf

in-pct-2001-0263-che claims.pdf

in-pct-2001-0263-che correspondences-others.pdf

in-pct-2001-0263-che correspondences-po.pdf

in-pct-2001-0263-che drawings-duplicate.pdf

in-pct-2001-0263-che drawings.pdf

in-pct-2001-0263-che description (complete)-duplicate.pdf

in-pct-2001-0263-che description (complete).pdf

in-pct-2001-0263-che form-1.pdf

in-pct-2001-0263-che form-19.pdf

in-pct-2001-0263-che form-26.pdf

in-pct-2001-0263-che form-3.pdf

in-pct-2001-0263-che form-5.pdf

in-pct-2001-0263-che others.pdf

in-pct-2001-0263-che petition.pdf