Patent ID: 7085471

Claim:
A light grid for generating a plurality of spaced-apart, parallel radiation beams comprising a first housing defining a transmitting unit and a second housing defining a receiving unit for detecting an object passing between the housings when the object crosses at least one of the beams, each housing having an open front side facing the other housing and an aft side facing away from the other housing, spaced-apart housing sides extending over the length of the housing, a plurality of intersecting spaced-apart bracing walls connecting the housing side walls to each other and forming open-ended passages that extend from the front side of the housing to the aft side of the housing, the bracing walls substantially preventing radiation transmissions between the passages, a radiation source for generating a radiation beam and a first optical element optically aligned with the source arranged in the first housing for directing the radiation beam from the source past the first optical element directly to the second housing in at least preselected ones of the open-ended passages, and a radiation receiver and a second optical element optically aligned with the receiver arranged in the second housing for receiving the radiation beam directly from the first housing in preselected ones of the open-ended passages in the second housing which correspond to the preselected open-ended passages in the first housing so that, upon activation of the radiation source, the radiation beams extend from the first housing to the second housing and an interruption of at least one of the radiation beams by the object is detected by the radiation receiver.