Patent ID: 7720566

Claim:
A system for use in association with a vertical package conveyor apparatus, said conveyor apparatus including a vertically movable chain and plural horizontal carrier trays attached to said chain and vertically separated from each other, operation of said conveyor apparatus being characterized by continuing vertical movement of said chain whereby said carrier trays move correspondingly with said vertical movement of said chain, the system comprising a processor-controller and plural electromechanical devices, said electromechanical devices being connected to said processor-controller and said conveyor apparatus, said processor-controller being capable of receiving and processing information provided by said electromechanical devices and being capable of regulating said operation of said conveyor apparatus, said regulation of said operation of said conveyor apparatus including monitoring whether an unsafe condition exists in said operation of said conveyor apparatus and further including ceasing said operation of said conveyor apparatus upon determining that said unsafe condition exists in the operation of said conveyor apparatus, said ceasing of said operation of said conveyor apparatus including ceasing of said vertical movement of said chain, said unsafe condition pertaining to the safety of humans in the vicinity of said conveyor apparatus, said electromechanical devices including at least one light curtain breach sensor and at least one light curtain muting sensor, said at least one light curtain breach sensor being for establishing, and sensing breaching of, at least one light curtain proximate said conveyor apparatus, said at least one light curtain muting sensor being for sensing when at least one said carrier tray is in a position in which said breaching of at least one said light curtain is not unsafe; wherein said unsafe condition is determined by said processor-controller to exist with respect to at least one said light curtain when said at least one light curtain breach sensor provides some said information that is indicative of said breaching of at least one said light curtain, and when said at least one light curtain muting sensor does not provide any said information that is indicative of said position of at least one said carrier tray in which said breaching of at least one said light curtain is not unsafe; and wherein said unsafe condition is determined by said processor-controller not to exist with respect to at least one said light curtain when said at least one light curtain muting sensor provides some said information that is indicative of said position of at least one said carrier tray in which said breaching of at least one said light curtain is not unsafe.