Abstract: A system for operating a vehicle storage conveyor is disclosed in which a programmable digital computer system is used to automatically control the operation of the conveyor, to monitor the safeties of the storage conveyor and to cease operation thereof upon the detection of an unsafe condition, and for controlling a plurality of electromagnetic radiation beam transmitting and detecting devices systematically located throughout a loading area of the storage conveyor so as to detect the presence of a vehicle or a person and to distinguish between them. The system prevents operation of the vehicle conveyor until the vehicle is properly positioned thereon and the person who drove the vehicle is detected as leaving the conveyor loading system.

Abstract: Electromagnetic radiation object position detection system and method are disclosed for detecting when an object is located in the path of a powered sliding gate. In a preferred embodiment, polarized microwave radiation is emitted from a source fixed relative to the sliding gate. This radiation is projected along and spaced ahead of the leading edge of the sliding gate by a redirecting means which moves with the gate. A second redirecting means also moves with the gate and redirects the radiation back to a detector fixed relative to the sliding gate which provides a signal when this radiation is detected. The presence of an object in the path of the sliding gate is indicated by the blockage of radiation in the beam moving with the leading edge of the sliding gate.

Abstract: Electromagnetic radiation position detection system and method are disclosed for detecting when a movable object is located at a predetermined position. In a preferred embodiment, polarized microwave radiation emitted from a source fixed relative to the movable object is rotated when the object is in an aligned position and a detector fixed with respect to the movable object and located opposite the fixed source provides a signal when substantially only the rotated, polarized radiation is detected. In one particular embodiment, a plurality of conveyor pans which are part of a car parking tower is the movable object and each pan carries a waveguide which rotates the microwave radiation propagated therethrough. The conveyor pan also has a wheel well with a switch located therein and which, when depressed by the tire of a properly located car on the conveyor pan acts to block the radiation from being detected.