Patent ID: 7578156

Claim:
A method of securing a machine having first and second tool parts that define an opening gap between them, at least the first tool part being movable relative to the second tool part in a movement direction so that during an operating cycle the opening gap is gradually closed, the method comprising generating a protected zone so that it precedes the first tool part and extends over at least a portion of the opening gap in the direction of relative movement, monitoring one of an entire area of the protected zone that is transverse to the movement direction and a periphery of the area with an optoelectronic sensor and generating a danger signal in response to a breach of the protected zone, and when a size of the opening gap in the movement direction becomes smaller than the protected zone in the movement direction, continuously reducing the size of the protected zone in the movement direction of the first tool part so that during subsequent closing movements of the first tool part substantially the entire opening gap is within the protected zone.