GB1597216A - Swivel joint for a wiper for screens of motor vehicles - Google Patents

Description

(54) A SWIVEL JOINT FOR A WIPER FOR SCREENS OF MOTOR VEHICLES (71) We, ROBERT BOSCH GMBH, a German company of Postfach 50, 7 Stuttgart 1, Federal Republic of Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The invention concerns a swivel joint one joint part of which is connectible to a wiper arm and the other joint part is connectible to a wiper blade, a bearing pin of the one joint part being accommodated in a bearing bush of the other joint part. The bearing pin and the bearing bush are provided with detent and recess formations by means of which the joint parts are secured against unintentional detachment.

In such a joint the detent and recess formations are arranged on the bearing pin and in the bearing bush, respectively, as a result of which the guide surface in the joint is diminished. Because of the unavoidable fabrication tolerances and the wear in this joint which occurs during operation of a wiper, the play in the joint can relatively soon exceed the permissible measure, so that disturbances can occur during the operation of the wiper.

In accordance with the invention there is provided a swivel joint having a first joint part provided with a bearing pin, and a second joint part provided with a bearing bush which receives the bearing pin and with a guide pin within the bush, which guide pin is associated with a guide bearing within the bearing pin, the joint parts having interengaging formations arranged so that the parts are mutually non-displaceable in the direction of the axis of the bearing pin.

This joint has the advantage over the above prior art that thanks to the arrangement of an additional guide pin which moves in a special guide bearing, the guide surface in the joint is appreciably increased.

As a result the unit stress in the joint is reduced and the life and operational reliability of a wiper incorporating the joint are increased. As a further advantage may be mentioned the fact that thanks to the arrangement of the guide pin and the guide bearing the compact type of construction of the swivel joint is maintained.

The invention is described further, by way of example, with reference to the accompanying section through a swivel joint on an enlarged scale.

As can be seen from the figure, the one joint part 12 of a swivel joint 14 is attached to a wiper arm 10. The one joint part 12 comprises a swivel bearing bush 16 wherein is accommodated a swivel bearing pin 18 of the other joint part 20. The other joint part 20 is provided with a receiving part 22 for a wiper blade (not shown in the drawing). The joint parts 12 and 20 are provided with interengaging formations in the form of an annular groove 24 in swivel bearing bush 16 and an annular bulge 26 on the swivel bearing pin 18. In this manner the two joint parts 12 and 20 are so connected that they cannot unintentionally become detached from one another in the direction of the swivel axis. To improve the guiding in the swivel joint, the one joint part 12 is provided with a guide pin 28 made integral with it which moves in a guide bearing 30 arranged coaxially to the axis of the swivel bearing pin 18 in the same, so that the swivel bearing pin 18 has a tubular cross-section.

Thus the support of the swivel joint is achieved not only by the swivel bearing pin 18 and the swivel bearing bush 16 associated with it, but also by the guide pin 28 adapted so that it fits into the guide bearing 30. In this manner the bearing and guiding joint surface is appreciably increased and the unit stress of the joint surfaces is diminished which brings about a decisive reduction in the wear of the joint parts.

Furthermore the swivel joint 14 comprises a torsion spring 32 which in mounted condition embraces the swivel bearing pin 18, and one end of which is anchored in the one joint part 12 and the other end in the other joint part 20. The torsion spring 32 is accommodated in a space 34 which is formed by a steplike shoulder 36 in the joint part 12 and by a groove 38 on the side face in the joint part 20.

The wiper device can be mounted optionally with or without torsion spring. It is the purpose of the torsion spring to maintain the two joint parts 12 and 20, or rather the wiper arm 10 and the wiper blade (not shown in the drawing) in a predetermined position from which a swivel movement of the wiper blade against the tension of the torsion spring 32 is possible.

WHAT WE CLAIM IS: 1. A swivel joint having a first joint part provided with a bearing pin, and a second joint part provided with a bearing bush which receives the bearing pin and with a guide pin within the bush, which guide pin is associated with a guide bearing within the bearing pin, the joint parts having interen gaging formations arranged so that the parts are mutually non-displaceable in the direc tion of the axis of the bearing pin.

2. A joint as claimed in claim 1, in which the guide pin is an integral part of the second joint part.

3. A joint as claimed in claim 1 or 2, in which one end of a torsion spring embracing the axis of the bearing pin and mounted under initial tension is anchored to each of the two joint parts.

4. A joint as claimed in any preceding claim wherein one of the joint parts is mounted on a driven wiper arm, and where in the other of the joint parts is connected to a wiper blade such that the axis of the bearing pin is substantially perpendicular to the wiping plane.

5. A joint as claimed in claim 4, in which the bearing pin with the guide bearing is arranged on the joint part joined to the wiper arm.

6. A joint constructed substantially as herein particularly described with reference to and as illustrated in the accompanying drawing.

7. A wiper including a joint as claimed

Claims (1)

1. in claim 6.