Patent ID: 7746233
Filing Date: 2010-06-29
Classification: G01D,H03K

Abstract:
1. A safety switch for monitoring a closed position of a guard door in an automated installation, said guard door comprising a fixed part and a moveable part, and the safety switch comprising: an actuator and a sensor each adapted to be secured to one of the parts, wherein the actuator has a transponder including an actuator antenna and the sensor has a sensor antenna, wherein the antennas are configured to establish a transponder coupling, when the parts are in the closed position, wherein the sensor antenna has a magnetic directional characteristic which allows the transponder coupling in at least two spatial directions that are mutually perpendicular as seen from the sensor antenna, and further wherein the magnetic directional characteristic comprises a stronger first preferential direction and a weaker second preferential direction allowing the transponder coupling, wherein the sensor antenna is arranged in an antenna housing having housing walls, and wherein a distance between the sensor antenna and the housing walls in the first preferential direction is longer than in the second preferential direction.