Title of Invention

WIPER ARM

Abstract

The invention is based on a wiper arm (10) which is constructed from a fastening part (12) and an articulated part (14) which is articulated on a first region (16) of the fastening part (12) via a tilting hinge (22) and has a wiper rod (24) on which a wiper blade is articulated, the fastening part (12) being firmly fitted with a second region (18) on a drive shaft (20) and being clamped to the articulated part (14) via a tension spring (28). It is proposed that the fastening part (12) has a device (34, 36, 42) which permits a defined bending, in the direction of a vehicle window, of that first region (16) of the fastening part (12) which points towards the articulated part (14).

Full Text

The invention is based on a wiper arm. Known window wipers have a wiper arm which comprises a fastening part and an articulated part which is articulated thereon and has a wiper rod. Articulated on the latter is a wiper blade which is constructed from a supporting-bracket system having a main central bracket and secondary intermediate brackets, which are connected in an articulated manner, and also claw-type brackets, and from a wiper strip. At its end pointing towards the fastening part, the articulated part has a spring chamber for a tension spring. The spring chamber is open towards the vehicle window and has, towards the wiper rod, a slot-shaped widened area with a first fastening point to which a retaining bracket of the tension spring is fitted. A c-shaped bracket is provided at the other end of the tension spring, the said bracket being fitted to a fitting device of the fastening part, which device serves as second fastening point. Furthermore, the articulated part is supported via a hub on a bolt shaped hinge spindle which is arranged in a first region of the fastening part facing the articulated part. The hinge formed in this manner, which is also called a tilting hinge, and the fitting device of the tension spring are arranged with respect to each other in such a manner that the tension spring pulls the articulated part and the wiper rod together with the wiper blade in the direction of the vehicle window. In order to clean or install the wiper blade, the articulated part of the window wiper is tilted away from the vehicle window. For this purpose, the articulated part is pivoted about the hinge spindle of the tilting hinge, the tension spring taking up a position in which it pulls the articulated part against a stop which is supported on the fastening part and restricts the pivoting movement. A second region of the fastening part is seated on the free end of a drive shaft which is mounted in a wiper bearing and is driven by a wiper motor, via a crank and a linkage. The said wiper motor is held by a mounting plate which is fastened on a vehicle body and contains the wiper bearings. The wiper bearings themselves frequently serve as fastening points by protruding through openings of the vehicle body and being screwed to the vehicle body with the interposition of vibration-damping, rubber-elastic elements. That end of the drive shaft which protrudes out of the vehicle body constitutes a considerable source of risk for injuries in the case of accidents with pedestrians. Crash standard draft directives of the European Commission (EC II1/5021/96 EN) define maximum acceleration values with regard to accidents with pedestrians, so-called head injury criteria, on the wiper system in the region of the vehicle bonnet. These criteria cannot be achieved with the customary wiper systems, even if the vehicle bonnet covers the drive shaft, since even in this case it is not ensured that the distance between the vehicle bonnet and the drive shaft is large enough, particular in the case of small bonnet gaps, One possible variant to remedy this is for the end of the drive shaft to be shifted further into the engine compartment. Vehicle manufacturers require a minimum distance of 65-85 mm between the vehicle bonnet and the end of the drive shaft. This also increases its distance from the articulated part, as a result of which a longer fastening part is required. In addition, the fastening part still protrudes, at least during wiping, into the striking region of a pedestrian. DE 198 03 344 Al discloses a wiper system having a displaceable drive shaft. According to this specification, the protruding end of the drive shaft is displaced into the vehicle body if an axial force of a predetermined size acts from the outside on the shaft end. In this case, means are provided for damping of the impact between an inwardly acting stop of the drive shaft and a part which is connected fixedly to the vehicle body, or between such a part and the vehicle body, the said means deforming plastically and/or elastically under the effect of a critical axial force in the axial direction, so that the end of the drive shaft is displaced in a defined manner into the engine compartment. Means of this type may be a plastically deformable sheet-metal sleeve which expediently has a corrugated region in the axial direction, or thin-walled, plate-shaped elements, a number of which can be arranged in a row in terms of action, depending on the displacement path. These elements can have such little play with respect to the drive shaft or to other adjacent components that, when they are deformed, they are placed against these components and reinforce the damping effect by means of friction. Finally, the means can be arranged in such a manner that they are compressed or pulled apart from one another under the action of the critical axial force. In addition, the drive shaft can be secured axially with respect to the bearing housing of the wiper bearing via form-fitting elements which have a predetermined breaking point and which break or are bent ovdr into a clearance under a critical axial force. Predetermined breaking points of this type can be produced by notches, holes or shearing pins. Apart from the fact that some solutions of this principle are structurally very complex, it is also only effective if the striking takes place in the region of the end of the drive shaft. Advantages of the invention Accordingly the present invention provides a wiper arm which is constructed from a fastening part and an articulated part which is articulated on a first region of the fastening part via a tilting hinge and has a wiper rod on which a wiper blade is articulated, the fastening part being firmly fitted with a second region on a drive shaft and being clamped to the articulated part via a tension spring, characterized in that the fastening part has a device which permits a defined bending, in the direction of a vehicle window, of said first region of the fastening part which points towards the articulated part. In the event of being struck, for example by a pedestrian's head, the wiper arm immediately yields in the region of the fastening part and of the articulated part. The pedestrian involved in the accident does not then strike against rigid obstacles, as a result of which the risk of injury is reduced. In one refinement of the invention, a predetermined breaking point of the fastening part forms the device for bending the wiper arm. The said predetermined breaking point is expediently designed as a notch and/or as a perforation in the side walls of the fastening part and is arranged on the end pointing towards the drive shaft. One or more notches and/or perforations weaken the effective cross section of the fastening part in the direction of the impact, with the result that, in the case of an impact with a correspondingly large force on the wiper arm, the fastening part breaks in a specific manner at this point and the wiper arm is pressed towards the vehicle window. The wiper arm always has to be replaced after an accident. This desi9n can advantageously be realized with little structural complexity and does not require additional components. It may also, however, additionally be used for other known measures, since it is also effective if the impact takes place at a distance from the drive shaft and a displacement of the drive shaft is made more difficult by tilting moments. As a further variant, the bending device is formed by a hinge which connects that second region of the fastening part, which is connected fixedly to the drive shaft and is designed as a separate component, to a first region, which is likewise designed as a second component. The pivoting movement of the hinge is restricted in the tilting direction by a stop. The latter supports the press-on force, applied by the tension spring, of the wiper arm on the vehicle window and prevents the fastening part from yielding when the wiper is tilted. In the case of an impact against the first part of the fastening part in the direction of the vehicle window, the said fastening part yields by tilting about the axis of the hinge. In order to compensate for the weight of the articulated part and of the wiper parts fastened thereto in the tilted position of the wiper arm, a spring in the form of a tension spring is expediently provided, the line of action of which spring runs between the hinge axis and the stop and which acts on the two components of the fastening part. In order to make a transportation position and tilted position more stable, it is advantageous to design the hinge as a latching hinge, in which the prestressing of the spring increases from a latching position, which corresponds to the operational and transportation position, if the first component is pivoted relative to the second component. This can be achieved by an arrangement of the fastening point of the spring on the second component relative to the hinge pin by the said fastening point being arranged offset towards the drive shaft. Furthermore, with regard to the line of action of the spring in the latching position, correspondingly designed latching surfaces or latching cams can be provided on both sides. In one variant, the hinge has a hub which is integrally formed on the one component of the fastening part and has a bearing hole which is designed as a slot in the longitudinal direction of the fastening part and in which a hinge pin, which is integrally formed on the second component of the fastening part, engages. The slot can be open towards the fastening part for easier installation. In the operational state, the two components are mutually supported via the hinge pin and the stop and are held in this position by the spring. The pre stressing of the spring ensures that the pre-assembled components of the fastening part do not fall apart during their transportation. If a critical impact force acts on the wiper arm, the spring force is overcome and the first component of the fastening part bends towards the vehicle window. The bending region of the fastening part causes the tilting hinge also to be tilted away to a certain extent out of the operational position. In this variant, the operational state of the wiper arm can advantageously be produced again very easily by the two hinges being folded back or automatically folding back again into their starting position. A prerequisite for this is that the components of the wiper arm have not been damaged overall by the impact. Since the latching hinge and the tilting hinge have a similar manner of action and are clamped via a tension spring, in one refinement of the invention, only one common tension spring is provided for both of them, the said tension spring being held between a first fastening point on the articulated part and a second fastening point on the first part of the fastening part by means of a sheathed cable. The tension spring can be assigned to the fastening part or to the articulated part, in addition, this variant manages without the c-shaped bracket of the tilting hinge, with the result that less space is required between the wiper arm and the vehicle window. In principle, in the case of all of the variants of the invention, protection against injuries is provided in the entire movement region and in the parking position of the wiper arm. In addition, the basic and tried and tested construction of the wiper arm can be retained. The same also applies for the manufacturing processes for producing the wiper arm. The changes according to the invention to the individual components of the wiper arm require only a small additional outlay, for example because of adapting injection moulds or bending tools. 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 on their own and put them together to form sensible further combinations. In the drawing: Fig. 1 shows a longitudinal section through a wiper arm in the operational position, Fig. 2 shows a variant of Fig. 1, Fig. 3 shows an enlarged illustration of a detail III from Fig. 2 without a spring. Fig. 4 shows a variant of Fig. 3 with a spring, Fig, 5 shows a further variant of Fig. 3 with a spring, Fig. 6 shows a plan view corresponding to an arrow VI in Fig. 5, Fig, 7 shows a longitudinal section through a wiper arm in a bent position, Figs 8-9 show variants of Fig. 1, Fig* 10 shows a longitudinal section through a wiper arm in the position for changing a wiper blade. Description of the exemplary embodiments A wiper arm 10 essentially comprises a fastening part 12 and an articulated part 14 having a wiper rod 24 (Fig. 1) . A wiper blade (not illustrated in greater detail) is connected in an articulated manner to the free end of the wiper rod 24. The articulated part 14 is connected to the fastening part 12 by a tilting hinge 22, In the operational position shown, the two parts are clamped relative to each other by a tension spring 28. For this purpose, the tension spring 28 is fitted at one end in an eyelet 2 6 on the articulated part 14 and is fitted at the other end on a pin 3 2 of the fastening part 12 via a c-shaped bracket 30. The fastening part 12 of the wiper arm 10 is seated fixedly on the free end of a drive shaft 20. In the vicinity of the drive shaft 20, the fastening part 12 has a notch 34 and a perforation 3 6 in the side walls of its U-shaped profile. By means of the said notch and perforation, the cross section is weakened in such a manner that, in the event of an accident, during the impact of a person, the cross section serves as a predetermined breaking point and the fastening part 12 yields slightly and/or breaks at this point in the direction of an impact force 54. In this case, the size and number of notches 34 and perforations 36 are selected in such a manner that the fastening part 12 does not break under normal conditions, even under a load of snow. The predetermined breaking part marked by the notch 34 and the perforation 3 6 divides the fastening part 12 into a first region 16, which faces the articulated part 14 and bends under impact, and into a second region 18, which is fastened to the drive shaft 20. In one refinement of the invention, the device for the defined bending of the fastening part 12 is formed by a hinge 42 (Fig. 2), The latter connects the first, bendable region 16 of the fastening part 12, which is defined as a separate component, to the second region 18, which is connected fixedly to the drive shaft 20 and is likewise designed as a separate component. A stop 56 restricts the pivoting movement of the hinge 42 in the tilting direction, whereas the said hinge can pivot freely towards the vehicle window, that end of the first component 16 of the fastening part 12 which forms the stop 56 following a circular-arc-shaped contour 64 having a radius 66 about the hinge pin 4 8. In the operational position of the wiper arm 10, by means of the force of the tension spring 28, the first component 16 is pressed with the stop 56 against the second component 18 and thus transmits the reaction force to the press-on force of the wiper arm 10 to the drive shaft 20. In order, in the tilted position (Fig. 10) , to compensate for the weight of the articulated part 14 and of those parts of the window wiper which are connected thereto, and to keep the fastening part 12 in an extended position in this position, a spring 46 is expediently provided, which spring is fitted with one end on a pin 38 of the first component 16 and with the other end on the pin 4 0 on the second component 18 (Fig. 2), The line of action of the spring 46, which is designed as a tension spring, runs between the stop 56 and the hinge pin 48 so that a stable equilibrium is produced. The stability of the position can be improved by the hinge 42 being designed as a latching hinge, the prestressing of the spring 46 in the pivoting direction significantly increasing on both sides of the latching position by the distance between the pins 38, 40 being enlarged. This can be achieved by an appropriate arrangement of the pin 4 0 on the second component relative to the hinge pin 48, for example by it being offset towards the drive shaft 2 0. Another possibility is for the components 16, 18 to be supported via latching surfaces 50, 52 or latching cams which shift the components 16, 18 relative to each other during the pivoting movement, it being possible for the hinge pin 4 8 to move in a hub which is designed in cross section as the slot 44 {Fig. 4). The slot 44, which extends in the longitudinal direction of the fastening part 12, can be open towards the articulated part 14 for simpler installation (Fig. 5), The latching surfaces 50, 52 can be provided at any desired, suitable point between the first and second components 16, 18, for example in the end region of the side walls of the cross-sectionally U-shaped profile of the first component 16 (Figs 5 and 6) . In the case of an impact, an impact force 54 acts on the fastening part 12 and the first component 16 of the fastening part 12 bends, A hinge pin 4 8 forms the axis of rotation and the first component 16 slides along the latching surfaces 50, 52, the prestressing of the spring 46 initially being increased. The wiper arm 10 finally takes up the position illustrated in Fig. 7. The impact force 54 has the effect that the articulated part 14 is also tilted from the extended position of the operational position. However, it is ensured, by corresponding dimensioning of the tension spring 2 8, that the articulated part 14 does not entirely fold upwards into the tilted position (Fig. 10). After an impact, the two hinges 22, 42 can be set back again. In this case, that end of the U-shaped profile of the first component 16 of the fastening part 12 which points towards the drive shaft 2 0 forms a stop 56, The stop 56 prevents the first component 16 from bending outwards firstly under the press-on pressure of the window wiper and secondly during tilting of the articulated part 14. In a further refinement of the invention, a common tension spring 28 or 46 is provided for the tilting hinge 22 and the latching hinge 42, the said tension spring being fastened by means of a sheathed cable 58 between the eyelet 26, which serves as a first fastening point on the articulated part 14, and a pin 40, which serves as a second fastening point on the second component 18 (Figs 8 and Fig. 9) , The sheathed cable 58 is guided between two guide elements 60 on the fastening part 12 in the region of the tilting hinge 22. In Fig. 10, the articulated part 14 is tilted away virtually vertically upwards so that a wiper blade (not illustrated in this drawing) which is articulated on the wiper rod 24 can be changed. In this position, an elastic stop 62, for example a rubber buffer, which is arranged at the end of the articulated part 14 in the region of the tilting hinge 22 expediently prevents the first component 16 of the fastening part 12 from being able inadvertently to strike against the vehicle window. WE CLAIM : 1. Wiper arm (10) which is constructed from a fastening part (12) and an articulated part (14) which is articulated on a first region (16) of the fastening part (12) via a tilting hinge (22) and has a wiper rod (24) on which a wiper blade is articulated, the fastening part (12) being firmly fitted with a second region (18) on a drive shaft (20) and being clamped to the articulated part (14) via a tension spring (28), characterized in that the fastening part (12) has a device (34, 36, 42) which permits a defined bending, in the direction of a vehicle window, of said first region (16) of the fastening part (12) which points towards the articulated part (14). 2. Wiper arm (10) as claimed in claim 1, wherein the device is a predetermined breaking point (34, 36) of the fastening part (12). 3. Wiper arm (10) as claimed in claim 2, wherein the predetermined breaking point is formed by a notch (34) or perforations (36) in the side walls of the fastening part (12). 4. Wiper arm (10) as claimed in claim 1, wherein the first and second regions (16, 18) are separate components which are connected by the device constructed as a hinge (42) whose pivoting movement is restricted in the tilting direction by a stop (56). 5. Wiper arm (10) as claimed in claim 4, wherein, in an operational position, a spring (46) presses the first region (16) against the stop (56) and is configured in such a manner that it bears the weight of the wiper arm (10) in the tilted position of the wiper arm (10), 6. Wiper arm (10) as claimed in claim 4, wherein the hinge (42) has a hub with a bearing hole which is constructed in cross section as a slot (44) in the longitudinal direction of the fastening part (12) and in which a hinge pin (48) engages, the parts (16, 18) of the fastening part (12) being mutually supported in the operational position via latching surfaces (50, 52) or on the hinge pin (48) and the stop (56). 7. Wiper arm (10) as claimed in claim 6, wherein the slot (44) is open towards the articulated part (14). 8. Wiper arm (10) as claimed in any one of claims 4 to 7, wherein the spring (46) is a tension spring. 9. Wiper arm (10) as claimed in claim 8, wherein a common tension spring (28, 46) is provided for the tilting hinge (22) and the hinge (42), the said tension spring being fastened between a first fastening point (26) on the articulated part (14) and a second fastening point (40) on the second component (18) of the fastening part (12) by means of a sheathed cable (58) , the sheathed cable (58) being guided between two guide elements (60), which run transversely to the longitudinal direction, on the fastening part (12) in the region of the tilting hinge (22), 10. Wiper arm (10) as claimed in any one of claims 4 to 9, wherein end of the articulated part (14) which faces the fastening part (12) has an elastic stop (62) which points towards the vehicle window in a tilted position. 11. Wiper arm, substantially as hereinabove described and illustrated with reference to the accompanying drawings.

Documents:

abs-in-pct-2002-1667-che.jpg

in-pct-2002-1667-che-abstract.pdf

in-pct-2002-1667-che-claims filed.pdf

in-pct-2002-1667-che-claims granted.pdf

in-pct-2002-1667-che-correspondence others.pdf

in-pct-2002-1667-che-correspondence po.pdf

in-pct-2002-1667-che-description complete filed.pdf

in-pct-2002-1667-che-description complete granted.pdf

in-pct-2002-1667-che-drawings.pdf

in-pct-2002-1667-che-form 1.pdf

in-pct-2002-1667-che-form 18.pdf

in-pct-2002-1667-che-form 26.pdf

in-pct-2002-1667-che-form 3.pdf

in-pct-2002-1667-che-form 5.pdf

in-pct-2002-1667-che-other documents.pdf

in-pct-2002-1667-che-pct.pdf