Title of Invention

WIPER DEVICE AND METHOD FOR ADJUSTING THE BEARING FORCE OF A WIPER ARM

Abstract Wiping device and method, in particular for a motor vehicle, with a wiper arm (10) which can be connected at one end (12) to a wiper blade (13) and is connected, in the region of its other end (14), to a tension element (22) which presses the one end (12) of the wiper arm (13) in the direction of a wiping surface (20) with a force F, an adjusting element, in particular an eccentric pin (30), being provided for setting the force F. Figs.lb&3b
Full Text

The invention relates to a wiping device and a method for adjusting the bearing force of a wiper arm.
Numerous wiping devices for motor vehicles are already known, in which a wiping blade which is fastened to a wiper arm and is pressed against the screen of the motor vehicle with the aid of a tension spring in order to generate a wiper-arm bearing force. For this purpose, the wiper arm is fastened pivotably by means of a hinge pin to a rotary head which is connected fixedly in terms of rotation to the wiper shaft and which executes, for example, an oscillating movement. The tension spring is in this case hooked with one end on the wiper arm and with its other end into a pin on the rotary head on the side facing the screen. In such systems, the bearing force can be varied or set only by exchanging the spring or a shackle holding the spring for another spring or another shackle.
Advantages of the invention
The advantage of the wiping device according to the invention, having the features is that the wiper-arm bearing force can be set individually for each individual wiping device with the aid of an eccentric pin as an adjusting element.
Tolerances in the spring constant and tolerances in the position of the components which determine the arrangement of the spring and the spring prestress itself give rise to a relatively wide spread of the bearing forces between the individual wiping devices of a series. The result of this is that the average bearing force of all the wiping devices of a series must be fixed in such a way that a good wiping quality is afforded even when the bearing force of the individual wiping device is on the edge of the tolerance range of the series. On the one hand, this tolerance range is limited by the wiper motor, since the design of the latter incorporates the bearing force linearly into the calculation and, in the case of a maximum bearing force, say a maximum frictional force of the wiping rubber, the wiper motor must still always be capable of operating the wiping device. On the other hand, the tolerance range is limited by the high-speed behaviour. In the case of a minimum bearing force of the wiper arm and

consequently of the wiper blade, an acceptable wiping result must be achieved even at high speeds.
A predetermined wiper-arm bearing force can be set by means of the adjusting element in a very simple way, without the use of additional components or the complete exchange of these.
Advantageous developments and improvements of the features specified herein may be gathered from the measures listed herein.
If the wiper arm is connected pivotably at its end to a rotary head and the tension element between the wiper arm and the rotary head is tensioned, the bearing force can be set exactly, for example a separate test stand, and then the rotary-head/tension-element/wiper-arm combination can be mounted on the wiping device.
If the tension element is hooked on the rotary head around the eccentric pin, during assembly the said tension element can be mounted in only a short time and transmits the adjusting movement uniformly.
If, furthermore, the tension element consists of at least one tension spring which is hooked around the eccentric pin by means of a hook, commercially available cost-effective tension springs can be used.
If the adjusting element has external knurling for fixing, advantageously the said adjusting element cannot rotate, during operation, as a result of the torque acting on the eccentric pin, as a result of which adjustment would be lost.
It is particularly advantageous if the adjusting element has an inner or outer polygon or a slot or cross slot for the adjusting operation. The latter can thereby easily be carried out by means of a commercially available tool.
At the same time, it is particularly advantageous if the eccentric pin, after being rotated, is secured, which may take place, for example, by riveting, embossing, pressing-in or welding.
It is advantageous, furthermore, if the eccentric pin has three cylindrical portions, the two outer portions along its longitudinal extent having a coaxial

mid-axis and the middle portion having a mid-axis which is different from the coaxial mid-axis and, in particular, is axially parallel. In this way, not only the prestress of the tension element can be varied, but, in particular, also the torque acting on the wiper arm, since the distance between the spring force acting along the axially parallel mid-axis and the hinge pin is varied during rotation of the eccentric pin.
If the two outer portions have different diameters, during assembly the eccentric pin can be inserted more easily and, for example, is secured against falling out. It is, of course, also advantageous, in this case, if the pin has a chamfer on at least one side.
If the eccentric pin can be inserted into the bore of the rotary head and has a partial knurling along one of the two outer portions, it is advantageous if the middle portion of the eccentric pin is configured in such a way, in particular has a width such that the tension element can be hooked into the eccentric pin, without the knurling and the bore being in engagement. Thus, during assembly, the eccentric pin can be introduced into the bore, and the tension element adjusted and then secured against the rotation by the eccentric pin being knocked in completely, since a positive and non-positive connection between the bore and the eccentric pin is thereby formed only after the end of adjustment.
The advantage of the method according to the invention is that a positive connection between the eccentric pin and the rotary head is achieved, without any loss of adjustment accuracy having to be accepted, since the eccentric pin can be knocked in any angular position.
Drawing
An exemplary embodiment of the invention is illustrated in the accompanying drawings and is explained in more detail in the following description. In the drawings:
Figure la shows a wiper arm with wiper blade and a rotary head of a wiping device according to the invention.

Figure lb shows a diagrammatic view of the hooked-in tension element as a detail,
Figure 2 shows a perspective illustration of an eccentric pin, and
Figure 3 a shows a diagrammatic sectional illustration of an eccentric pin with knurling during assembly and during adjustment, and
Figure 3b shows an eccentric pin like that in Figure 3a after locking.
Description of the exemplary embodiment
Figure la shows a wiper arm 10 of a wiping device according to the invention. The said wiper arm has two ends, a wiper blade 13 being fastened to one end 12.
The wiper arm 10 is articulated pivotably at the other end 14 on a rotary head 16 by means of a hinge pin 15. The rotary head 16 has, at its end facing away from the wiper arm 10, a receiving bush 18 for fastening an output shaft, not illustrated, of the wiping device. The wiper blade 13 is articulated on one end 12 of the wiper arm 10 and rests on a wiping surface 20. If a wiping device is installed in a motor vehicle, the wiping surface corresponds to the windscreen or the rear window of the vehicle.
A tension element 22 is fastened to other end 14 of the wiper arm 10 on that side of the wiper arm 10 which faces the wiping surface 20. The said tension element consists of a tension spring 24 and of a hook 26 which in each case are hooked under prestress on that side of the wiper arm 10 and of the rotary head 16 which faces the wiping surface 20. By the tension element 22 being tensioned, the wiper arm 10 is pressed, about its hinge pin 15, with one end 12 in the direction of the wiping surface 20 with the force F.
Figure lb illustrates in detail the other end of the wiper arm 10 having the tension element 22. A tension spring 24 of the tension element 22 is hooked, within the two flanks of the U-shaped profile of the wiper arm 10, around a crosspin 28 which passes through the U-shaped profile part of the wiper arm 10 at a distance A from the hinge pin 15. The tension spring 24, on its other side, hooks into the hook 26 which, in turn, is hooked around an eccentric pin 30 as an adjusting

element. A torque about the hinge pin 15 thereby acts on the wiper arm 10. Eccentric pin 30 is in this case seated completely within a bore 42 of the rotary head 16. By the eccentric pin 30 being rotated, the prestress of the tension spring 24 can thereby be varied, with the result that the bearing force F, with which one end 12 of the wiper arm presses the wiper blade 13 against a wiping surface 20, is varied.
Figure 2 illustrates the eccentric pin 30 in detail. The latter has essentially three cylindrical portions, the two outer portions 32 along its longitudinal extent having a coaxial mid-axis 34. The mid-axis of the middle portion 36 is different from the coaxial mid-axis 34, in particular is axially parallel to the coaxial mid-axis 34.
The radius of the middle portion 36 is always smaller than or equal to the difference between the radius of the outer portions 32 and the distance between the coaxial mid-axis 34 and the axially parallel mid-axis 46, or, in other words, the cross section of the middle portion 36 is always within the circle predetermined by the cross section of the outer portions 32, since the eccentric pin 30 could otherwise n be introduced in the bore 42.
On at least one of the end faces 38 of the eccentric pin 30, the latter has a slot 40 which makes it possible to rotate the eccentric pin 30 within the bore 42 of the rotary head 16. It is, of course, also possible to arrange a cross slot or an inner or outer polygon on the end face 38, so that adjustment can be carried out by means of a commercially available tool. If eccentric pin 30 is introduced in the bore 42 of the rotary head 16, the bearing force F or the prestress of the tension element 22 can be set by means of a rotation of the eccentric pin 30 and then the eccentric pin can be secured against rotation, for example, by means of riveting, embossing, pressing-in or welding.
In order to prevent the eccentric pin 30 from falling out during assembly, the two outer portions 32 may also have different radii.
Figure 3 illustrates a section through a rotary head 16 in the region of the eccentric pin 30. The eccentric pin in this case has a knurling 44 as a securing

element on one of its outer portions 32 on its side facing away from the middle portion 36. The middle portion 36 is dimensioned, in terms of its longitudinal extent, in such a way that the hook 26 of the tension element 22 can be hooked around the middle portion 36, without the knurling 44 being in engagement with the bore 42. In this way, the bearing force F can be adjusted, and, at the end of the adjusting operation, the eccentric pin 30 can be pressed into the bore and consequently locked, so that a positive connection between the bore 42 and the knurling 44 secures the eccentric pin 30 against rotation. This is illustrated in Figure 3b.
The method according to the invention can be carried out by means of an eccentric pin 30 illustrated in Figure 3. In this case, the eccentric pin 30 has, along its longitudinal extent, a partial knurling 44 as a securing element.
In the first step, the eccentric pin 30 is inserted into the bore 42, but only to an extent such that the knurling 44 is not yet countersunk in the bore 42. The middle portion of the eccentric pin 30 is in this case of a width such that even this partial insertion is sufficient to hook the hook 26 of the tension element 22 around the eccentric pin.
In a second step, the bearing force F is set by means of a rotation of the eccentric pin 30, and then, in a third step, the eccentric pin 30 is pressed into the bore 42, so that the knurling 44 makes a positive or non-positive connection with the bore 42.
At the same time, of course, a polygon, an individual boss or the like instead of the knurling 44, may also serve as a securing element.
Instead of the eccentric pin 30, in a variation of the invention, it is also possible, for example, to use a pin which, in the middle region along its longitudinal extent, has a screw element which passes through. If this screw element, with its side facing away from the head, is in engagement with the hook 26, the head of the screw element can be rotated for adjustment and consequently the spring prestress increased.



WE CLAIM :
1. Wiping device, in particular for a motor vehicle, with a wiper arm (10) which is connected at one end (12) to a wiper blade (13) and is connected, at a distance (A) from its other end (14), to a tension element (22) which comprises a tension spring (24) and which presses the one end (12) of the wiper arm (10) in the direction of a wiping surface (20) with a force F, characterized in that an eccentric pin (30) is provided as an adjusting element for setting the force F.
2. Wiping device as claimed in claim 1, wherein the wiper arm (10) is connected pivotably at its other end (14) to a rotary head (16), and the tension element (22) between the wiper arm (10) and the rotary head (16) is tensioned.
3. Wiping device as claimed in claims 1 or 2, wherein the tension element (22) is hooked on the rotary head (16) around the adjusting element (30).
4. Wiping device as claimed in any one of the preceding claims, wherein the tension element (22) is hooked around the adjusting element (30) by means of a hook (26).
5. Wiping device as claimed in any one of the preceding claims, wherein the adjusting element (30) has a knurling (44) for fixing.
6. Wiping device as claimed in any one of the preceding claims, wherein the adjusting element (30) has an inner or outer polygon, a slot (40) or a cross slot on its end face for adjustment.


8. Wiping device as claimed in any one of the preceding claims, wherein the eccentric pin (30) has three cylindrical portions (32, 36), the two outer portions (32) along the longitudinal extent having a coaxial mid-axis (34), and the middle portion (36) having a mid-axis (46) that differs from the coaxial mid-axis (34).
9. Wiping device as claimed in claim 8, wherein the two outer portions (32) have different diameters.
10. Wiping device as claimed in claim 8 or 9, wherein the eccentric pin (30) is inserted into a bore (42) of the rotary head, in that has, along one of the two outer portions (32) a partial knurling (44), particularly in the axial direction, for locking, and in that its middle portion (36) is configured so that the tension element (22) is adjusted without the knurling (44) and the bore (42) being in engagement.
11. Method for adjusting the bearing force of a wiper arm (10) of a wiping
device, in particular as claimed in any one of the preceding claims, having at
least the following steps:
partial insertion of an eccentric pin (30), which has along its longitudinal extent, at least partially, a securing element, in particular a knurling (44), into a bore (42),
setting of the bearing force at least by rotating said eccentric pin (30),

pressing-in of the eccentric pin (30) at least to an extent such that substantial portions of the securing element (44) are located within the bore (42).


Documents:

abs-in-pct-2002-886-che-1.jpg

abs-in-pct-2002-886-che-2.jpg

in-pct-2002-886-che- abstract.pdf

in-pct-2002-886-che- claims.pdf

in-pct-2002-886-che- correspondence others.pdf

in-pct-2002-886-che- correspondence po.pdf

in-pct-2002-886-che- descripition complete.pdf

in-pct-2002-886-che- drawings.pdf

in-pct-2002-886-che- form 1.pdf

in-pct-2002-886-che- form 26.pdf

in-pct-2002-886-che- form 3.pdf

in-pct-2002-886-che- form 5.pdf

in-pct-2002-886-che- other documents.pdf

in-pct-2002-886-che- pct.pdf


Patent Number 243008
Indian Patent Application Number IN/PCT/2002/886/CHE
PG Journal Number 40/2010
Publication Date 01-Oct-2010
Grant Date 23-Sep-2010
Date of Filing 12-Jun-2002
Name of Patentee ROBERT BOSCH GMBH
Applicant Address POSTFACH 30 02 20, D-70442 STUTTGART, GERMANY
Inventors:
# Inventor's Name Inventor's Address
1 ZIMMER, JOACHIN UHLANDSTRASSE 5, 77880 SASBACH, GERMANY
PCT International Classification Number B60S1/34
PCT International Application Number PCT/DE01/03171
PCT International Filing date 2001-08-18
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 100 51 570.3 2000-10-18 Germany