Patent ID: 7448625
Filing Date: 2008-11-11
Classification: B41F

Abstract:
1. An apparatus for conveying a sheet through a printing machine, comprising: a cylinder formed with a channel therein; grippers disposed in said channel for holding the sheet at a leading edge thereof; a delivery for forwarding the sheets, the delivery including: circulating leading-edge grippers for holding and for transferring the sheet from said cylinder at the leading edge, and circulating, radially positionable, trailing edge suction grippers for holding the sheet at a trailing edge thereof; an actuating apparatus for opening and closing said leading edge grippers and for controlling a vacuum for said trailing edge suction grippers; a drive for said cylinder and said circulating leading-edge grippers and said trailing edge suction grippers; a control device for selectively switching on and off a sheet feed to said cylinder; a chain conveyor with endless chains having fixed thereto said leading-edge grippers; rotating chain wheels carrying said endless chains; coaxially circulating supporting elements for the sheet disposed between said chain wheels assigned to said cylinder, said supporting elements being in rolling contact with a peripheral surface of said cylinder and being movably mounted in a direction of an axis of rotation of said chain wheels in dependence on a sheet transverse format; and at least one valve spool connected to said supporting elements via a pull cable, for switching off respective said trailing edge suction grippers disposed laterally outside a given sheet width; wherein said trailing edge suction grippers are mounted to be moved in a radial direction into a rest position when the sheet feed is switched off, said trailing edge suction grippers are moveable in the radial direction into a rest position in dependence on a sheet width of the sheet when the sheet feed is switched on, and said trailing edge suction grippers are movably disposed in the radial direction into the rest position as a result of an actuation of positioning elements for the axial displacement of said supporting elements.