Detecting the completion of shutter blade piling by measuring the displacement of the motor frame and using the second time derivative to detect the onset of predetermined play in the mechanism

摘要

The shutter driving motor frame is connected to a cylinder (10) whose end (9) is joined to a testing element (7). The testing element (7) is also fixed to a fixed base (2). When the motor lowers the shutter plates the displacement of the cylinder (10) is measured by brushes (23) on resistive tracks and the completion of shutter blade piling is determined either by detection of half track voltage or measurement of the second time derivative of the displacement