Importance

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Abstract

An appliance which, through motor-driven operation, is movable toward a closing edge, in particular, for use with window regulators and sliding roofs of automotive vehicles. For this purpose, the number of revolutions of the motor is permanently detected, with the number of revolutions of the motor being measured in successive measuring intervals. The number of revolutions is to be a measure of the force acting on the pane. Respectively the last four measured values are detected in a sliding register and are subjected to evaluation. For this purpose, first a start-up value is detected. The start-up value respectively is the third last measured value n.sub.i-3 if the difference D between the current measured value and the third last measured value does not exceed a predetermined differential threshold D.sub.max. For, in that case, the start-up value remains unchanged. Subsequently, the difference A is formed between the start-up value and the current value n.sub.i. If the latter is above a predetermined response threshold A.sub.max, the anti-clamping system responds. This means that the driving motor is turned off and, optionally, is inverted in the direction of rotation thereof. More specifically, the forces acting on the pane are successively integrated from one measured interval to the next as long as there is some sort of increase from one measured interval to the next. As soon as the integration value A reaches the response threshold A.sub.max, the anti-clamping system responds. In this way a sensitive and rapidly responding protection against clamping is realized, wherein error signals based on fluctuations in the frictional resistance of the pane guide are suppressed.

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First Claim