Abstract: Apparatus for moving two individual bins between their separate loading stations and a common unloading station includes a length of conveyor on which one bin always rests and a set of pivotable lever arms, the other bin being connected to one end of one set of lever arms. Another set of lever arms is connected to the first lever arms and carries cam followers which are constrained to simultaneously follow two sets of cam tracks, one of which is stationary within the apparatus and the other of which is affixed to the one bin. When a bin at the unloading station is empty the apparatus will move that bin to its own loading station while bringing the other bin from its loading station to the unloading station. Interaction between the cam followers and the cam tracks moves the one bin back or forth on the conveyor while the other bin member is moved in a vertically arcuate path. The loading station of the other bin is vertically spaced above the loading station of the one bin.