Deflecting roller for sensing the distribution of stress along the roller

Abstract

A deflecting roller for sensing the distribution of stress along the roller while the roller deflects a strip of sheet material, and in particular, a deflecting roller having a plurality of stress sensors disposed around the roller such that the stress sensors sense the radially acting force on the roller, without contributing any interfering forces thereto. The roller has a plurality of measuring locations defined about the circumference of the roller. Each measurement location includes a recess in the roller; a stress-responsive sensor disposed in the recess; and a sensor cover positioned within the recess so as to cover the stress-responsive sensor. The sensor cover has the same cross sectional shape as the recess so that the sensor cover is guided by the wall of the recess for radial movement with respect to the roller. The sensor cover does not rest on a shoulder in the recess. Instead, an inside surface of the sensor cover bears against one end of the stress-responsive sensor, while the outside surface of the sensor cover is convex to match the circumferential shape of the roller. In operation, when the measuring roller acts to deflect a piece of sheet metal, the sensor cover is forced further into the recess by the piece of sheet metal, and as a result, the sensor cover compresses the stress-responsive sensor between the bottom of the recess and the inside surface of the sensor cover.