Patent ID: 9346091
Filing Date: 2016-05-24
CPC Classification: B21D,B30B,F16P

Claim Text:
1. In a machine having a first machine part configured to perform a working movement towards a second machine part in order to process a workpiece at an end of the working movement, said first machine part comprising a leading edge in the direction of the working movement, a safety device comprising: a light transmitter and a light receiver arranged in a predefined relationship relative to the first machine part, said light transmitter generating a light beam that runs along the leading edge and illuminates the light receiver during the working movement, and said light receiver comprising an image sensor having a plurality of pixels for capturing an image produced by the light beam, an evaluation unit designed to evaluate selected pixels from the plurality of pixels and to generate a stop signal for stopping the first machine part in response to the selected pixels, wherein the selected pixels span a protective field which has a two-dimensional cross section including an upper region in the area of the leading edge, the protective field moving with the first machine part ahead of the leading edge during the working movement, and an optical measuring barrier arranged ahead of the protective field in the direction of the working movement, wherein the evaluation unit is configured to hold the protective field substantially stationary immediately above the workpiece at the end of the working movement in response to the optical measuring barrier and sequentially muting the selected pixels synchronously with the working movement starting with the selected pixels in said upper region, and wherein the evaluation unit is further configured to reduce the two-dimensional cross section of the protective field at the end of the working movement in order to allow the first machine part to process the workpiece.