Sheet feeding or delivering – Delivering – With transfer means between conveyor and receiver
Reexamination Certificate
2000-11-22
2003-04-08
Mansen, Michael R. (Department: 3654)
Sheet feeding or delivering
Delivering
With transfer means between conveyor and receiver
C271S204000, C271S280000
Reexamination Certificate
active
06543764
ABSTRACT:
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The invention relates to a method for separating out individual sheets from a sheet-processing machine, in particular, at the delivery of a printing machine with pile or stack formation, by a revolving gripper chain having gripper bars extending transversely to the sheet conveyance direction, and grippers which are arranged on the gripper bars and successively grip the sheets at the leading edge thereof and convey them to a stacking or pile region to be deposited, whereat, in order to separate out the sheets, they are conveyed over and beyond the stacking or pile region and, at a predefinable location, are transferred to a separating device having a controllable revolving suction belt for braking and separating out the sheets.
In order to assess or evaluate the printed image in a printing machine, individual printed sheets, so-called proofs, must be removed at regular intervals during progressive operation. In the case of stack-building or pile-forming printing machines, these proofs have heretofore been removed manually from the progressively forming stack or pile.
German Patent 195 19 374 describes a device for automatically separating out individual printed sheets with the aid of a second separating device arranged behind the stacking region and serving for conveying an incoming sheet out of the delivery of the machine and depositing it on an extensible table. The desired sheets are drawn beyond the stack region to the aforementioned second separating device by a gripper chain revolving continuously at the machine cycle rate in order to convey the printed sheets, and are transferred, at the second separating device, to a revolving suction belt, instead of being deposited on the sheet pile as usual.
Through the intermediary of the revolving suction belt, the sheets are braked to an output speed. In the course of the braking, the sheets behave differently, depending upon the stiffness of the paper, and the machine speed. Failures or faults occur because of sheets entrained by the grippers, as well as due to collisions with succeeding sheets at high machine speed.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention of the instant application to provide a method of separating out individual sheets in a printing machine, which functions reliably and irrespectively of the paper being processed and the speed of the machine.
With the foregoing and other objects in view, there is provided, in accordance with one aspect of the invention, a method for separating out individual sheets from a sheet-processing machine, by a revolving gripper chain having gripper bars extending transversely to a direction wherein the sheets are being conveyed, and grippers arranged on the gripper bars for gripping the sheets one after another at a leading edge thereof and conveying them to a stacking region for deposition, whereat, the sheets to be separated out are conveyed over and beyond the stacking region and, at a predefinable location, are transferred to a separating device having a controllable revolving suction belt for braking and separating out the sheets, which comprises bringing the suction belt to sheet speed, picking up with the suction belt a respective sheet to be separated out, and opening the grippers, somewhat braking the suction belt briefly and, after withdrawal of the respective sheet from the grippers, accelerating the suction belt again to at least the previous speed thereof, and outputting the respective sheet while it is being braked.
In accordance with another mode, the method of the invention for separating out individual sheets, includes performing the separation at a delivery of a printing machine capable of sheet pile formation.
In accordance with a further mode, the method of the invention includes, after the respective sheet has been withdrawn from the grippers, accelerating the respective sheet beyond the original speed thereof, and reestablishing the original travel spacing of the respective sheet from the next following sheet before braking the respective sheet.
In accordance with an added mode, the method of the invention includes, after the respective sheet has been withdrawn from the grippers, accelerating the respective sheet beyond the original speed thereof, and moving it farther away from the next following sheet a spaced distance greater than the spaced distance originally therebetween, and then outputting the respective sheet while it is being braked.
In accordance with an additional aspect of the invention, there is provided a method for separating out individual sheets from a sheet-processing machine, by a revolving gripper chain having gripper bars extending transversely to the direction in which the sheets are being conveyed, and grippers arranged on the gripper bars for gripping the sheets one after another at a leading edge thereof and conveying them to a stacking region for deposition thereat, further conveying the sheets to be separated out, over and beyond the stacking region and transferring the sheets, at a predefinable location, to a separating device having a controllable revolving suction belt for braking and separating out the sheets, which comprises, upon the arrival of a sheet to be separated out, bringing the suction belt to sheet speed, applying suction by the suction belt to the sheet, opening the grippers, accelerating the suction belt to a higher speed, after releasing the sheet from the grippers, and then outputting the sheet while braking the sheet.
In accordance with yet another aspect of the invention, there is provided a sheet-processing machine capable of sheet stack formation, having a device for separating out individual sheets by a revolving gripper chain having gripper bars extending transversely to a sheet-conveyance direction, and grippers arranged on the gripper bars for gripping the sheets one after another at a leading edge thereof and conveying them to a stacking region for deposit thereat, the sheets to be separated out being conveyable over and beyond the stacking region and, at a predefinable location, being transferrable to a separating device having a controllable revolving suction belt for braking and separating out the sheets, comprising equipment for bringing the suction belt to sheet speed, for causing a sheet, that is to be separated out, to be picked up by the suction belt, for opening the grippers, for braking the suction belt briefly, and for accelerating the belt again to at least the previous speed thereof, after the sheet has been withdrawn from the grippers, and for finally outputting the sheet while braking it.
In accordance with yet a further aspect of the invention, there is provided a sheet-processing machine capable of sheet stack formation, having a device for separating out individual sheets by a revolving gripper chain having gripper bars extending transversely to the direction in which the sheets are being conveyed, and grippers arranged on the gripper bars for gripping the sheets one after another at a leading edge thereof and conveying them to a sheet stacking region for deposit thereat, the sheets to be separated out being conveyable over and beyond the stacking region and, at a predefinable location, being transferrable to a separating device having a controllable revolving suction belt for braking and separating out the sheets, comprising equipment by which, upon the arrival of a sheet to be separated out, the suction belt is bringable to sheet speed, for causing the sheet to be picked up by the suction belt, for opening the grippers, for accelerating the suction belt to a higher speed, after releasing the sheet from the grippers, and for finally outputting the sheet while braking it.
In accordance with a concomitant feature of the invention, the sheet-processing machine is a rotary printing machine, and the device for separating out individual sheets is located at a delivery of the rotary printing machine.
When a stiff paper quality is being used, the aforestated object of the invention is readily achievable. However, when
Greenberg Laurence A.
Heidelberger Druckmaschinen AG
Locher Ralph E.
Mansen Michael R.
Stemer Werner H.
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