Arrangement for monitoring the drawing of the supporting frame in a cutter shield

摘要

The invention relates to an arrangement for monitoring the drawing of the supporting frame in a cutter shield, the supporting frame of which can be drawn up by means of the jacks allocated to the driving cutters. In order to prevent the driving cutters from unintentionally running back during the drawing of the supporting frame, at least one of the driving cutters is provided with a switching device which, by striking against a fixed abutment (end casing) during the cutter return, triggers a warning signal and/or a control signal blocking the drawing of the supporting frame. The switching device preferably consists of a switch which is provided with a holding magnet, adheres magnetically to the driving cutter and is held by a holder at the fixed abutment (end casing) so that it cannot be carried along by the driving cutter when the latter is advanced.