Automatic switching system for propelled carriers

Claim 1

A transportation system including main line rails and switching rails substantially colevel throughout the length thereof with said main line rails, said switching rails including an initial portion parallel to the main line rails, carriers movable over said rails, means for propelling said carriers, switching means for moving said carriers between said main line rails and said switching rails, said switching means comprising main line wheels mounted on said carrier for engagement with said main line rails, switching wheels mounted on said carrier for vertical movement between a raised inoperative position and a lowered operative position, said switching wheels in the lowered position thereof having the rail engaging portion thereof below the rail engaging portion of said main line wheels, and means operative to move said switching wheels to their lowered operative position for engagement with said switching rails with a conjoint vertical lift of said carrier and disengagement of said main line wheels from said main line rails, said switching rails including a proximal ramp portion forwardly and upwardly inclined to provide a ramp for engagement by said switching wheels upon continued forward movement of said carrier whereby the forward movement of said carrier facilitates the lifting thereof.