Abstract: A sliding door having a safety light beam which travels with and ahead of a closing door. Interruption of the safety light beam by an object in the path of the closing door activates a door control to stop or reverse the closure of the door. A stationary transmitter projects a beam of pulsed infrared light to a convex mirror mounted on the door. The mirror reflects the projected beam ahead of the closing door in a direction transverse to the direction of closure. In one embodiment a plurality of receiver assemblies with overlapping receiving sectors monitor the door closure path and sense the presence of the moving safety beam. Interruption of the safety light beam is detected in a control unit connected to a unit which controls a motor that moves the door. In another embodiment, plane mirrors positioned on an arm mounted on, and projecting ahead of the door, establish and reflect safety beams to corresponding receiver assemblies.

Abstract: A coil winding machine for winding arrays of closely-spaced, irregularly shaped coils utilizes a winding head that moves elliptically about the coil being wound. The elliptical motion permits compact arrays to be produced economically by allowing more closely spaced coils to be wound than can be wound with a winding head having circular motion. The machine is programmable automatically to step between coils of the array, and to wind the coils in any desired direction. A turns counter is utilized gradually to slow the head prior to the completion of each winding operation, and a position detector is used to position the head between rows of coils as the head is advanced to the next coil to be wound.

Abstract: A cross point switching matrix utilizing remanent reed switches includes an array of coil forms mounted on a magnetically permeable shunt plate. Electromagnetic coils are wound around the coil forms in alternating directions and one or more remanent reed switches are contained in each coil. Magnetically permeable coupler plates are mounted on opposite sides of the shunt plates and serve to complete a magnetic path between the ends of each reed switch and the shunt plate through the other reed switches. When two or more reed switches are mounted in each coil, the switches are disposed in a straight line aligned at a 45.degree. angle to the coordinates of the matrix to permit electrical connections to be readily made to the reed switches utilizing straight conductors.