Patent ID: 6467582
Filing Date: 2002-10-22
Classification: B65G,B66F

Abstract:
A stacker crane having a vertically extending mast containing an elevating platform and being attached between an upper cart and a lower cart, and means for maintaining said mast in a vertical attitude, comprising:vertically spaced upper and lower rails, said upper and lower carts connecting the upper and lower ends, respectively, of said mast, said carts each having runner wheels engaging said upper and lower rails, respectively, separate running motors operable to drive each of said carts, and control means for controlling at least one of said running motors so that the upper and lower carts overlie each other on a vertical line, said control means comprising: a laser operated range finder associated with each of said carts, and a control system operative to activate the running motor of at least one of said carts for moving said at least one cart in response to a comparison of signals generated by said range finders.