Control drive for a stack lift drive in sheet processing machines, more particularly sheet printing machines

US5295678A · kind A · utility

Assignee

• MAN Roland Druckmaschinen AG · DE

Inventors

• Bernd Lindner · Frankfurt, DE
• Albrecht Volz · Rödermark, DE
• Joachim Blumor · Großkrotzenburg, DE

Key dates

• Filing date: Oct 29, 1992
• Grant date: Mar 22, 1994
• Expiry date: Oct 29, 2012

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B65H1/18
• WIPO field: Handling
• WIPO sector: Mechanical engineering

Abstract

A system and method for controlling the lifting of a stack of sheets to be printed in order to keep the currently uppermost sheet of the stack within a certain predetermined height range for reliable removal to a feed table. A motor is operated in either a discontinuous mode or in a continuous mode to lift the sheets, the mode of operation being chosen in dependence on the speed of the press and the thickness of the sheets when compared against an established curve. A sensor is utilized to determine the vertical position of the uppermost sheet in the stack. In the continuous mode the motor speed is adjusted in accordance with the height of the uppermost sheet in the stack, while in the discontinuous mode, the motor is energized and de-energized such that the height of the currently uppermost sheet in the stack is maintained within a predetermined height range.