Unit feeding sheets of paper to printing cylinder or transfer drum has pre-gripper and swinging transfer gripper driven in phase for sheet delivery speed below machine speed

摘要

The transfer gripper system is designed to swing. Its gripper strip (9) moves circumferentially, relative to the transfer drum (6). The pre-gripper (5) and swinging gripper system are driven in phase with each other, such that both delivery of the sheet into the take-over region and also picking-up of the sheet in this region by the transfer gripper system, takes place at sheet delivery speed (vt) less than the machine speed (v) in the take-off section. Vt in the take-over region is 50%-80% of the machine speed. The swinging gripper system is controlled by a cam. The pre-gripper is controlled by a cam running with the transfer drum. The swinging gripper system has an impact strip with several gripper-fingers coupled to it. The strip tilts about an axis (X7) parallel to the axis (X6) of the transfer drum and runs radially-offset from it. The pivoting axis of the strip is located within the transfer drum. At the instant of sheet take-over, this lies below a plane defined by the rotation axis of the transfer drum, and the front edge of the sheet being transferred. The sheet is picked up by the fingers of the pre-gripper. It follows a path (6b) lying above the path of the resting surface of the transfer drum. The front edges of the sheets grasped by the fingers, are guided to the resting surface path. An independent claim is included for the corresponding method.