Patent ID: 8119964
Filing Date: 2012-02-21
Classification: B21D,B30B,F16P

Abstract:
1. A safety device for a machine having a first machine part executing an operational movement towards a second machine part, the first machine part having an edge projecting in a direction of movement and defining a movement plane, the safety device comprising: a light transmitter, a light receiver coupled to the first machine part such that it runs ahead of the edge during the operational movement of the first machine part, and an evaluation unit, wherein the light transmitter comprises a light source having a predominantly incoherent radiation for generating a light beam that runs substantially parallel to the edge and illuminates the light receiver, wherein the light receiver comprises an image sensor having a plurality of pixels for recording a spatially resolved image of the light beam, and imaging optics having a focal point and an aperture stop which is substantially arranged at the focal point and has a clear inside diameter smaller than 1 mm, wherein the evaluation unit generates an output signal as a function of the spatially resolved image, and wherein the evaluation unit detects an inflection point in an intensity characteristic in the spatially resolved image that is monotonically rising or monotonically falling over a plurality of adjacent pixels in order to determine an edge location of an object that projects into the light beam.