Sheet transfer device for a printing machine

摘要

A sheet transfer device for a printing machine for taking over sheets which have been aligned at front lays and for transferring the sheets to a sheet-guiding drum includes a pregripper device swivellable between a sheet takeover and a sheet transfer position. Gripper pads are carried by the pregripper device, and a gripper shaft is swivel-mounted in the pregripper device and carries gripper fingers which are associated with the gripper pads. Also provided are a device for connecting the gripper shaft and the gripper fingers so that swivelling movements of the gripper shaft are transmitted to the gripper fingers, and a swivel device for swivelling the gripper shaft about a longitudinal axis thereof. A cam segment has a control surface for controlling the swivel device, and is adjustable so that a gap, formed between the gripper fingers and the gripper pads in the takeover position of the pregripper device and existing until alignment of the sheet at the front lays is terminated, is settable in accordance with the thickness of the sheets. The gap is so defined that the gripper fingers form top lays for a respective leading sheet edge. A control shaft is provided for adjusting the cam segment, the control shaft extending parallel to generatrices of the control surfaces and being arranged so as to be adjustable parallel to itself.