The application claims priority to DE 10 2004 033 984.8 which was filed on Jul. 14, 2004.
The invention relates to a clamping piece for holding a window pane in a window lifter. The clamping piece cooperates with a counter piece in order to clamp therebetween a movable window pane of a motor vehicle. The window pane can be moved by the window lifter between an open and a closed position. To this end, the clamping piece and the counter piece are fastened to a carriage, for instance, which can be moved by a mechanism of the window lifter, e.g. in a guide rail. The movement of the carriage, for instance in vertical direction, is transferred to the window pane via the clamping piece and the counter piece.
A bolt is commonly used to fasten the clamping piece to the counter piece. The bolt is screwed into a thread on the clamping piece. Traditionally, this thread is provided on a nut configured as a separate component, and which is fastened to the clamping piece. This will be explained briefly in the following with respect to FIGS. 1 to 3.
The clamping piece 5 is pulled towards the counter piece 7 by a bolt 11, which is screwed into a nut 13 shown more clearly in
This construction is disadvantageous, because it entails a relatively high expenditure in manufacturing. The nut 13 has to produced as a separate component and then has to be mounted to the clamping piece 5. Moreover, a special expenditure is required to fasten the nut 13 to the clamping piece 5 in such a reliable manner that the nut 13 will not come loose when the bolt 11 is repeatedly tightened and untightened.
It is the object of the invention to provide a clamping piece that can be produced under low expenditure and in which the nut can be repeatedly tightened and untightened.
To accomplish this objective, the subject invention provides a clamping piece comprising an annular lug that is configured in one piece with the clamping piece, and in which a thread-forming bolt can be screwed. The bolt pulls the clamping piece towards a counter piece in order to clamp a window pane between the clamping piece and the counter piece. The invention is based on the idea of eliminating the nut. In order to ensure that the bolt still has a reliable grip and the clamping piece can be pulled towards the counter piece, a lug is provided that is made in one piece with the clamping piece, and in which several turns can be formed. In this way a required tensile force is reliably provided. Further, the thread in the lug can be loaded to such an extent that the bolt can be tightened and untightened several times, for instance with maintenance or service activities in which the window pane has to be dismounted from the window lifter.
A low expenditure is involved to produce the lug on the clamping piece by deep-drawing or pressing, as the clamping piece usually is made of metal. The lug preferably has a wall thickness that is larger than a remaining wall thickness of the clamping piece. This can be ensured by suitable parameters during drawing of the lug. If necessary, the lug may subsequently be upset and/or calibrated in order to obtain the desired wall thickness. Upsetting is a processing step in which the lug is compressed and plastically deformed. Calibration is a processing step in which an opening in the lug is precisely defined by using a die, punch, or by machining for example.
These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.
The annular lug 15 is configured such that its wall thickness provides a desired strength of the thread formed therein. If the wall thickness of the clamping piece 5 is already comparably large, for instance 3 mm, the wall thickness of the lug 15 may be equal to the wall thickness of the remaining body of the clamping piece 5. If the clamping piece 5 is configured to have a comparably small wall thickness, however, the lug 15 may be made such that its wall thickness is larger than the remaining wall thickness of the clamping piece 5. This provides a high strength of the thread formed in the lug 15 and, hence, a high clamping torque for the bolt 11.
Also, the wall thickness of the lug 15 could be larger in a transition region to a body of the clamping piece 5 than on an end face of the lug 15. Such a parameter is another way to influence the strength of the formed thread.
The clamping piece 5 is made of metal and produced by punching, stamping, pressing or deep-drawing. The cylindrical lug 15 is pressed or deep-drawn, too. This results in a very low expenditure in manufacturing. As the entire clamping piece 5 is made from one single piece, there will be no expenditure for mounting additional components. Further, there is no risk of an incorrect mounting of additional components.
Although a preferred embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.
Number | Date | Country | Kind |
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10 2004 033 984.8 | Jul 2004 | DE | national |