Pregripper for a printing machine

US5575209A · kind A · utility

Assignee

• MAN Roland Druckmaschinen AG · DE

Inventors

• Harald Bayer · Rodgau, DE
• Klemens Kemmerer · Seligenstadt, DE

Key dates

• Filing date: Oct 25, 1995
• Grant date: Nov 19, 1996
• Expiry date: Oct 25, 2015

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B41F21/05
• WIPO field: Textile and paper machines
• WIPO sector: Mechanical engineering

Abstract

A pregripper for transferring sheets from a sheet feeder to a feed drum or impression cylinder of a printing machine is provided. The pregripper is disposed below the sheet feeder and includes a hollow tube which has a substantially pear-shaped cross-section. The pear-shaped cross-section is defined by a first apex having a greater curvature and a second apex having a lesser curvature relative to the first apex. The hollow tube also has an exterior wall having a thickness that increases as the wall extends from the first apex to the second apex. A web which supports a conventional gripper bridge is attached to the hollow tube adjacent the first apex. The hollow tube is rotatably supported on each end by a journal such that the axis of rotation of the hollow tube is substantially concentric with the center of curvature of the second apex. In an alternative embodiment, the hollow tube has a plurality of openings extending therethrough substantially in the transverse direction which are adapted to prevent the build-up of a dynamic air pressure between the sheets and the pregripper.