The invention relates to a wiper device to wipe a windshield, in particular a wiper device with wiper arm lift control.
In order to enlarge the wiped area of wiper devices, wiper arm lift controls are used, particularly in the form of four-bar wiper arms. Four-bar wiper arms essentially feature two connecting rod levers in addition to the actual wiper arm, each of which are connected to the wiper arm via an articulation. Because of an appropriate kinematic design, the wiper arm exerts a lifting and swiveling movement when the connecting rod levers are swiveled. Driving the four-bar wiper arm is accomplished via one of the two connecting rod levers, which as a drive lever is equipped with an electric drive. The second connecting rod lever, the control lever, is used to affect the lift of the wiper arm and is only fastened to a blind bearing, which does not transmit any torque.
The bearing force of the wiper arm on the windshield is normally generated by a tension spring. For this purpose, the wiper arm features a wiper arm articulation, wherein the tension spring is arranged in the articulation area of a two-piece wiper arm. While a coupling piece of the two-piece wiper arm is connected to the connecting rod levers, the wiper blade is arranged on the articulation part, and the wiper blade is pressed against the windshield with the aid of the tension spring. Alternatively, the pressure force of the wiper blade is generated with a compression spring, which is arranged in the articulation area of the wiper arm.
Providing the articulation in the wiper arm produces a relatively high design of the wiper arm in order to achieve sufficient rigidity in the area of the articulation. In addition, the tension springs and their fastenings require construction space, which increases the height of the wiper arm in the perpendicular direction with respect to the windshield.
In addition, the articulation normally has play, which increases further in the case of longer use of the wiper arm. This leads to a reduction in the service life of the wiper arm and can produce rattling and/or overshooting at the wiper arm's reversing positions.
It is the objective of the present invention to make available a four-bar wiper arm that is as flat as possible, which can be manufactured cost-effectively and has a favorable wear behavior.
In accordance with the invention, a wiper device to wipe a windshield of a motor vehicle is provided that features a wiper arm and two connecting rod levers. The connecting rod levers are connected to the wiper arm in a plane at fastening points so they can move rotationally. At least one of the connecting rod levers is executed to be elastic essentially perpendicular to the wiper plane in order to effect a pressure force from the wiper arm on the windshield in an installed state.
One idea of the present invention consists of making a four-bar wiper device available in which the requirement for the construction height of the wiper arm is reduced since the pressure force of the wiper arm or of the wiper location connected to the wiper arm is effected on the windshield via one or both connecting rod levers. The wiper arm can be embodied to be non-articulated in particularly due to the elastic design of the connecting rod lever since the pressure force is made available via the connecting rod lever. As a result, providing articulation in the wiper arm is dispensed with in a simple way as well as a corresponding tension or compression spring, which generates the pressure force on the windshield in embodiments in accordance with the prior art. Because the articulation is dispensed with, the construction height of the wiper arm can thereby be reduced and the wiper device is less susceptible to wear.
In addition, manufacturing is greatly simplified since the connecting rod lever can be embodied as a bar spring element.
In particular one of the connecting rod levers can be embodied as a drive lever and another of the connecting rod levers as a control level, wherein the wiper arm is swiveled and lifted by swiveling the drive lever around a swivel axis.
In order to achieve a pressure force from the wiper arm on the windshield, at least one of the connecting rod levers is pre-stressed in an installed state.
The connecting rod levers can each feature a fold-out mechanism in order to swivel the wiper arm into a maintenance position so that a wiper connected to the wiper arm can be serviced or replaced. In this case, the connecting rod levers are designed such that in the maintenance position they are able to project at an angle from the wiper plane or the windshield so the wiper arm is no longer resting on it and is therefore accessible.
The connecting rod levers can each feature a snap-in device in order to hold the connecting rod levers in the maintenance position, wherein the connecting rod levers are designed such that they are able to exit the maintenance position by moving the connecting rod levers back into the wiper plane via the exertion of a restoring force.
According to another embodiment, the connecting rod levers are made of a deep-drawing material in order to be able to manufacture them as simply as possible, e.g., using a stamping process.
In particular the connecting rod levers can be coupled with the wiper arm and/or with the swivel axes at the fastening points with the aid of a caulked fastening element.
Preferred embodiments of the present invention are explained in more detail in the following on the basis of the enclosed drawings. They show:
a and 6b Depictions of a connecting rod lever with fastening elements and bearing bolts in an unstressed and installed state.
As can be seen in the depiction of the rear of the wiper device in
The articulation 6 in the wiper arm 3 is disadvantageous because it is subject to wear, which reduces its service life and produces rattling and overshooting in the reversing positions. This especially reduces the service life of the wiper arm so that it has to be replaced frequently.
In particular, the connecting rod levers 81, 82 are embodied as a drive lever 81 and as a control lever 82 in order to achieve the swivel and lifting movement of the wiper arm 10. The drive lever 81 has a swivel axis 11, where the electrical drive (not shown) of the wiper device engages and enables the movement of wiper device by a swiveling of the drive lever 81.
The connecting rod levers 8 are connected to the wiper arm 10 at the fastening points 9 so that they can move rotationally, i.e., torque cannot be transmitted between the connecting rod lever 8 and the wiper arm 10 essentially in one direction parallel to the wiper plane. The fastening points 9 are embodied in such a way, however, that the pre-stress force, which the pre-stressed connecting rod levers 8 exert on the wiper arm 10, presses the wiper arm 10 on the windshield 5.
Because of the lack of articulation on the wiper arm 10, it can be provided with a smaller construction height so that the flow of the wiper blade, which is rigidly connected to the wiper arm 10, progresses undisturbed. The coupling between the wiper blade 12 and the wiper arm 10 is achieved via a coupling element 13, which can be embodied in various ways and is used to connect the wiper arm 10 and the wiper blade 12 as rigidly as possible to one another via a swivel joint.
a and 6b depict a connecting rod lever 8 in an uninstalled and an installed state. One can see that the connecting rod lever in the uninstalled state has a curvature, and is essentially straight in the installed state so that the connecting rod lever 8 in an installed state is strongly braced as compared with the uninstalled state. The bracing of the connecting rod lever 8 effects the pressure force of the wiper arm 10 so that additional measures to generate a pressure force in the wiper arm 10 are not required. The connecting rod levers 8 are preferably executed geometrically as a bar spring element in such a way that the required bearing force for the wiper blade 12 is generated on the vehicle via the respective pre-stressing in a mounted state. In the case of bearing force being generated by the drive lever 81 and control lever 82, the pre-stress force on both connecting rod levers 8 is divided approximately in half in order to avoid an unnecessarily high stress of the fastening with the swivel axis 11 and at the fastening points 9. The elastic connecting rod levers 8 absorb the lifting movements of the wiper blade 12, e.g., due to the curvature of the windshield 5.
Another embodiment of the connecting rod lever 8 is depicted in
As shown in
The hair clasp mechanism can be integrated into the connecting rod levers 8 when embodying the connecting rod levers 8 as a stamped part; in particular with the use of such a fold-out mechanism, it is necessary to move the connecting rod levers 8 and the wiper arm 12 into a wiper blade change position in which both connecting rod levers 8 or connecting rod lever sections, which can be folded out with the hair clasp mechanism, lie essentially parallel to one another so that both connecting rod levers 8 are not twisted against each other during fold-out.
The connecting rod levers 8 can be manufactured in a simple manner as a stamped part, which can be brought into the curvature depicted in
In particular, an embodiment of the connecting rod lever 8 made of spring steel is meaningful.
An essential advantage of the present invention is that it is possible to build the wiper device with a lower construction height since an articulation in the wiper arm can be dispensed with. In addition, this results in less wear since the wiper arm is rigid and therefore no rattling or overshooting can occur in the reversing positions from play in the articulation in the wiper arm. The flat design is also advantageous for increased safety, e.g., with respect to protecting pedestrians in an impact. Particularly when using aero wiper blades, the wiper arm can be accommodated more simply in narrow hood gaps in the front panel because of the flat design.
Number | Date | Country | Kind |
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103 61 746.9 | Dec 2003 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/DE04/02435 | 11/4/2004 | WO | 5/18/2006 |