August R Bergemann

US Patent:

59080884, Jun 1, 1999

Filed:

Dec 27, 1996

Appl. No.:

8/773687

Inventors:

Mark R. Webster - Colgate WI
August R. Bergemann - Milwaukee WI
Gene M. Barth - West Bend WI

Assignee:

Pflow Industries Inc. - Milwaukee WI

International Classification:

B66F 904

US Classification:

187274

Abstract:

An improved hydraulic drive mechanism for a vertical conveyor. The conveyor comprises a pair of upright supports or columns and a carriage to support a load or cargo is guided for vertical movement on the columns. The drive mechanism includes a pair of first hydraulic cylinder units and a pair of second hydraulic cylinder units that preferably have twice the length of the first cylinder units. The first or shorter cylinder units are connected between a movable cross beam and the carriage, while the second cylinder units are connected between the movable beam and the upper end of the frame. At a lower level both the first and second cylinder units are in an extended condition, while at an upper level both cylinder units are retracted.