Gravity trolley conveyor with speed control

A gravity conveyor comprising first and second downwardly inclined tracks, the first track comprising two resiliently flexible, thin upright rails laterally spaced in generally parallel relation, the second track comprising at least one resiliently flexible, thin upright rail, a trolley suspended from said tracks and adapted to support and convey a workpiece therealong, said trolley comprising a retarder assembly, an arm depending from said retarder assembly and a support member at the lower end of said arm adapted to be loaded with a workpiece, said retarder assembly including a bracket, an axle journalled on said bracket for rotation on a generally horizontal axis, a retarder mechanism operably connected with said axle and responding to the angular velocity of the axle to apply a retarding torque thereto, first and second wheel sets fixed to the axle to rotate therewith, the first wheel set comprising two wheels of the same diameter spaced axially apart on said shaft to correspond with the lateral spacing of the rails of the first track so as to roll on the upper edges of said rails, the second wheel set comprising at least on wheel of different diameter than the wheels of the first set and adapted to roll on the upper edge of the rail of the second track, the two tracks being arranged such that, when the trolley is loaded with a workpiece, the wheel set of smaller diameter is arranged to roll on the rails of one of said tracks and, when the trolley is not loaded with a workpiece, the wheel set of larger diameter is adapted to roll on the rails of the other track.