Photoelectric sensing apparatus for pallet storage systems

Claim 1

In an automated storage system having a storage rack for receiving a quantity of loaded pallets with a reflecting surface thereon and a robot vehicle movable into and out of said storage rack for respectively retrieving and depositing loaded pallets from and onto said storage rack, said storage system comprising: means on said robot vehicle for lifting a loaded pallet and propelling said robot vehicle; logic means for controlling the operation of said propelling means; first and second photoelectric means mounted on said robot vehicle, said first means operative in response to a loaded condition of the vehicle for sensing the proximity of a loaded pallet on the storage rack ahead of said vehicle, and said second photoelectric means operative in response to an unloaded condition of said vehicle for sensing when said vehicle has been positioned underneath a stored pallet on the rack, said sensing means including a transmitter for projecting a light beam along a first axis, and a receiver for receiving a reflected light beam along a second axis, said transmitter and receiver being angularly oriented relative to each other to enable the first and second axis to intersect at a junction located in the same horizontal plate as a preselected reflecting surface of said pallet, said photoelectric sensing means having means for generating an electrical signal when the moving robot vehicle causes the sensing means to pass under said preselected reflecting surface thereby enabling the preselected surface to reflect the projected light beam from the transmitter to the receiver, and means for feeding said signal to said logic means.