Variable lift conveying apparatus

A conveying machine comprising a framework, guide means extending longitudinally of said framework defining a closed path of travel along a series of treating stations, a plurality of work carriers each including an upright carriage mounted for movement along said guide means and a carriage having a work supporting arm thereon mounted for movement on said carriage frame, multiple speed reversible motor means stationarily mounted on each said carrier frame and drivingly connected to each said carriage for moving said carriage between a raised position, a lowered position and at least one intermediate position therebetween;

• transfer means comprising a flexible element extending along the path of travel of said work carriers and connected to each said carriage frame and power means for intermittently advancing said flexible element and said work carriers in unison from one treating station to the next adjacent treating station, power supply means comprising a plurality of conductor rails extending longitudinally of said guide means at at least some treating stations, said conductor rails at each said station selectively and independently energizable relative to said conductor rails at other stations to provide independent selective vertical movement at selective operating speeds of said work carrier at each such station, connecting means comprising contacts on each work carrier for electrically connecting said motor means to said conductor rails of said power supply means when at said stations, sensing means for sensing the position of each said carriage on said carriage frame, and control means for coordinating said transfer means and selectively energizing said power supply means and sensing means to provide a controlled intermittent advancement of said work carriers and a vertical movement and positioning of each said carriage at a treating station at the desired said raised, lowered and intermediate position in accordance with a preselected operating sequence.