A method for assuring a safe work space operates so that a work enable signal is generated only when absence of workers from the work space where the workers work in cooperation with a machine is detected. The work enable signal has a logical value of 1 corresponding to a high energy state and only this...http://www.google.de/patents/US5345138?utm_source=gb-gplus-sharePatent US5345138 - Method and apparatus for assuring safe work
