GB2275261A

GB2275261A - Stacking sheets

Info

Publication number: GB2275261A
Application number: GB9402959A
Authority: GB
Inventors: Gregor Flade
Original assignee: Heidelberger Druckmaschinen AG
Current assignee: Heidelberger Druckmaschinen AG
Priority date: 1993-02-17
Filing date: 1994-02-16
Publication date: 1994-08-24
Anticipated expiration: 2014-02-16
Also published as: GB9402959D0; DE4304832C2; GB2275261B; DE4304832A1

Description

2275261 Sheet delivery with vertical sheet piling for a sheetprocessing

machine, particularly a printing press for offset printing The invention relates to a sheet delivery of a sheetprocessing machine, particularly a printing press for offset printing, with vertical sheet piling on horizontally acting conveying means for pile feed.

A pile device comprising said features is known from DEOS 32 64 112, wherein the sheets, supplied preferably non-cyclically from a folding machine, are piled, standing on a side edge and with their flat surfaces being more or less vertically aligned. For this purpose, the sheets are deflected with heavy bending between conveyor belts of a special feeding system and, at the exit of the conveyor belts of the feeding system, are pressed by a horizontally directed air stream against the front sheet in the pile of sheets, with the result that, for pile alignment, the sheets, gliding on one another, are displaced against one another as they enter the pile of sheets. This pile apparatus is unusable for sheets with a delicate surface, particularly for printed sheets from the printing unit of an offset printing press. Furthermore, for pile changing, the known pile apparatus requires an interruption in operation, because non-stop pile changing is not possible.

It is known from said publication to provide a first conveying means, consisting of a conveying worm at the entry,to the pile, and a second conveying means, consisting of an adjoining, vibratingly driven sheettransport table with laterally revolving transport belts for pile formation, said transport belts touching the 2 sheet side edges, with said second conveying means being intermittently driven.

A similar pile device is described also in DE-OS 27 21 441, wherein the incoming sheets are likewise fed between belts of a transport system with sharp bending of the sheets, with the result that the bending-up of the rear edge of a preceding sheet allows the front edge of the following sheet to be slid underneath, providing the formation of a continuous stream, whereby, for pile alignment, the sheets, likewise gliding on one another, are displaced against one another as they enter the pile of sheets.

The object of the invention is to design a sheet delivery with vertical sheet piling for continuous operation, wherein the sheets, without mutual contacting, are transported into the pile and only after they have been aligned in the pile of sheets do they, with a considerable time delay, come into contact with one another.

The object of the invention is achieved by the characterizing features according to claim 1.

The advantage of a design of the delivery with such characterizing features consists, firstly, in the continuous mode of operation of the pile device and, secondly, above all, in that the incoming sheets are initially kept at a distance from one another, only later being compressed to form a pile. In conjunction with a printing press, particularly an offset printing press.producing high-quality printed products, it is thus possible considerably to extend the time for the drying of the print and of any surface finishes of the print before the sheets come into mutual contact and form a pile. The separating section may be suitably dimensioned in length.

In a preferred embodiment of the invention, portioning elements for predetermined pile heights are provided at the transition of the conveying means in the separating section and of the conveying means in the compressing section, said portioning elements engaging, from the sides, a gap between two sheets and being driven in synchronism with the conveying means in the compressing section. This makes it possible, at intervals corresponding to specified pile heights, for gaps to be formed between two sheets in the pile, with intermediate boards, for example, being insertable into said gaps in order thus to allow the lifting-off of a pile section during otherwise continuous printing-press operation.

Particularly suitable as conveying means for sheet transport in the separating section and in the compressing section are endlessly revolving conveying belts, which, however, are driven at different feedrates. Furthermore, brush belts, driven at the feedrate of the conveying belts in the separating section, are additionally laterally disposed in the separating section, the bristles of said brush belts engaging the gaps between the sheets and thus keeping the sheets at a distance from one another in order thus to extend the time for the drying of the print and to create space for the additional arrangement of auxiliary devices for the promotion of drying, such as hot-air blowers.

Further characterizing features for advantageous embodiments of the invention are contained in claims 4 to 9.

A specimen embodiment of the invention is schematically represented in the drawings, in which:

Fig. 1 shows a side view of a delivery with the characterizing features according to the invention; and Fig. 2 shows a top view of the design according to Fig. 1.

The specimen embodiment comprises a delivery directly downline of the last printing unit of a printing press. The printed sheets 1 are taken from the impression cylinder 2 by grippers 3 of a transport chain 4 and are supplied to the delivery on a more or less vertically upwardly directed transport path. The grippers 3 release the sheets 1 slightly above the pile formation, with the result that the sheets are forced one after the other into the delivery by the horizontal air stream emanating from fans 5. The delivery comprises a first separating section A and a second compressing section B for approximately vertical sheet piling, wherein the individual sheets are positioned upright on a side edge -and are aligned approximately vertically with their flat surfaces. For the purpose of sheet transport, the delivery is provided with a conveying belt 6 in the separating section A and also with a conveying belt 7 in the compressing section B, the direction-reversal points of said conveying belts 6 and 7 facing and overlapping one another in order to allow the transport of sheets from the conveying belt 6 onto the conveying belt 7. The conveying belt 6 is driven at a higher feedrate than the conveying belt 7, with the result that the compression of the sheets in the.pile of sheets only takes place in the transitional region between the two conveying belts 6 and 7. In the separating section A, brush belts 8 are disposed laterally next to the sheets that are to be compressed in the pile of sheets, said brush belts 8 being driven at the same feedrate as the conveying belt 6 in the separating section A. The bristles of said brush belts 8 engage the gaps between the incoming sheets, thereby keeping said sheets at a distance from one another, with the result that the sheets 1 are transported in the separating section A more or less without mutual contacting. Disposed at the sides of the sheets above the brush belts 8 or below said brush belts, possibly also above and below the brush belts 8, are sheet aligners 9, which ensure a well aligned pile of sheets already in the region of the separating section. Disposed in the front region of the separating section A laterally next to the sheet sides and possibly also under the sheet sides are hot-air nozzles 16 or similar, by means of which it is possible to accelerate the drying of the prints.

Situated in the region of the compressing.section B at the sides of the pile of sheets are portioning elements consisting of revolvingly disposed belts 10 with finger wedges 11 advantageously adjustably attached thereto at intervals corresponding to a specified pile height, said finger wedges 11 laterally engaging, still in the separating section A or in a transitional region C, the gap between two sheets and being driven at the feedrate of the conveying belt 7 when the sheets are compressed in the sheet pile. Said finger wedges 11 comprise vertically continuous cutouts, which form guides for -intermediate boards 12 insertable from above, with the result that, at the front end of the delivery, it is possible for separated-off pile sections to be removed, for example, by means of a driverless transport system 13 or other auxiliary devices, without interrupting the continuous operation of the delivery. Claws 15 may be 6 disposed at the free ends of the forked arms 14 of such a driverless transport system 13, said claws 15 engaging the gap between the intermediate boards 12, so that the liftedoff pile section can be swivelled through approximately 900 5 in an anticlockwise direction and be transported away.

It will of course be understood that the present invention has been described above purely by way of example, and modifications of detail can be made within the scope of the 10 invention.

7

Claims

CLAIMS:

1. Sheet delivery apparatus for a sheet-processing machine, such as a printing press f or of f set printing, said apparatus comprising separate conveying means provided f or horizontally feeding sheets located vertically in a first separating section and in a following compressing section, said separate conveying means transporting the pile-forming sheets which are lifted off each other in the separating section at a higher feed-rate than in the compressing section, where they are formed into a pile.

2. Sheet delivery apparatus according to claim 1, wherein at a transition between the conveying means in the separating section and the conveying means in the compressing section, portioning elements are provided f or determining pile heights, said portioning elements engaging within a gap between two sheets and being driven in synchronism with the conveying means in the compressing section.

3. Sheet delivery apparatus according to claim 1 or 2, wherein endlessly revolving conveying belts, driven at dif f erent f eed-rates, are provided as the conveying means f or sheet transport in the separating section and in the compressing section, with brush belts, driven at the feedrate of the conveying belts in the separating section, being additionally laterally disposed in the separating section, the bristles of said brush belts engaging within the gaps between the sheets.

4. Sheet delivery apparatus according to claim 2 or claim 3 when dependent on claim 2, wherein the portioning elements consist of finger wedges disposed laterally in the compressing section next to the pile of sheets, said wedges being driven at the feed-rate of the conveying belts in the compressing section and engaging within a gap between two sheets.

a

5. Sheet delivery apparatus according to claim 4, wherein the finger wedges are adjustably attached, at intervals of a specified pile height, to endlessly revolving belts extending over (in the feed direction) the rear region of the separating section as well as over a partial region of the compressing section.

6. Sheet delivery apparatus according to claim 4 or 5, wherein the f inger wedges comprise vertically continuous cut-outs forming guides for intermediate boards insertable from above.

7. Sheet delivery apparatus according to any one of claims 1-6, wherein hot-air nozzles are directed onto the sheet side edges in the front region of the separating section.

8. Sheet delivery apparatus according to claim 3 or any one of claims 4-7 when dependent on claim 3, wherein sheet aligners are disposed in the separating section laterally next to the sheets above and/or below the brush belts.

9. Sheet delivery apparatus according to any one of claims 1-8, wherein a chain conveyor with sheet grippers for gripping the sheets by their front edges, transports the sheets, prior to delivery thereof, from bottom to top in front of the sheets, with fans being disposed to provide an air stream directed against the sheets.

10. Sheet delivery apparatus, substantially as hereinbefore described with reference to the accompanying drawings.