System for turning a sheet in a printing machine

US6089155A · kind A · utility

Assignee

• MAN Roland Druckmaschinen AG · DE

Inventors

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

Key dates

• Filing date: Mar 25, 1999
• Grant date: Jul 18, 2000
• Expiry date: Mar 25, 2019

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B41F21/108
• WIPO field: Textile and paper machines
• WIPO sector: Mechanical engineering

Abstract

The invention relates to a method and apparatus turning a sheet in a printing machine. More specifically, a swing arm is provided to grip a trailing edge of a sheet delivered on a first cylinder and transfer the gripped edge to a second cylinder. The invention provides low-outlay sheet-turning apparatus which provides smear-free sheet transportation. In conjunction with the swing arm, the second cylinder has secant-like flattened sections, or a non-circular cross-section, forming clearance areas within an outer circumference of the second cylinder as defined by a rotary path of radially outward portions of the second cylinder. In face-and-reverse printing mode, these clearances enable the swing arm to synchronously travel a sheet-feed path which intersects the circumference of the second cylinder. With this motion the swing arm draws the sheet from the first cylinder in a substantially tangential manner, avoiding dramatic curving of the sheet. The swing arm deposits the transferred edge of the sheet to a gripper on the second cylinder, which carries the sheet to a downstream cylinder. When the sheet is transferred onto the downstream cylinder, it is "turned over" relative to its in…