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Title:
DEVICE AND METHOD FOR REMOVING TRIM WASTE BY SUCTION IN A PRINTING-SUBSTRATE PROCESSING MACHINE
Document Type and Number:
WIPO Patent Application WO/2005/092580
Kind Code:
A1
Abstract:
A device (30) for removing trim waste (24) by suction in a printing-substrate processing machine (10), including at least one air duct (28) having at least one suction opening (26) and one apparatus (34) for producing an air flow (32) through the suction opening (26) into the air duct (28), the air duct (28) having at least one additional opening (42) which has a closing element (44) which enables the size of the additional opening (42) to be variably adjusted. The size of the at least one additional opening (42) of the air duct (28) is adjusted in such a way in accordance with the present invention that the apparatus (34) is operated at a constant load.

Inventors:
ROBIN PHILIPPE (FR)
THEVENIN THIERRY (FR)
Application Number:
PCT/IB2005/000268
Publication Date:
October 06, 2005
Filing Date:
February 03, 2005
Export Citation:
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Assignee:
GOSS INT MONTATAIRE SA (FR)
ROBIN PHILIPPE (FR)
THEVENIN THIERRY (FR)
International Classes:
A47L9/00; B08B5/04; B08B15/00; B26D7/18; B26D1/24; (IPC1-7): B26D7/18; A47L9/00; B08B15/00
Foreign References:
US4961245A1990-10-09
DE10106672A12002-09-12
DE10208607C12003-06-12
FR1086685A1955-02-15
US20030172827A12003-09-18
Attorney, Agent or Firm:
Domenego, Bertrand (2 Place d'Estienne d'Orves, Paris Cedex 09, FR)
Download PDF:
Claims:
WHAT IS CLAIMED IS:
1. A device (30) for removing trim waste (24) by suction in a printingsubstrate processing machine (10), comprising at least one air duct (28) having at least one suction opening (26) and one apparatus (34) for producing an air flow (32) through the suction opening (26) into the air duct (28), the air duct (28) having at least one additional opening (42), characterized in that the additional opening (42) has a closing element (44) which enables the size of the additional opening (42) to be variably adjusted.
2. The device (30) for removing trim waste (24) by suction as recited in claim 1, characterized in that the additional opening (42) is closable.
3. The device (30) for removing trim waste (24) by suction as recited in claim 1 or 2, characterized in that the air duct (28) includes a substantially ttubular end piece (36), in whose first leg (38) the suction opening (26) is located and in whose second leg (40) the additional opening (42) is located.
4. The device (30) for removing trim waste (24) by suction as recited in one of the preceding claims, characterized in that the device (30) includes a flow velocity meter (50).
5. The device (30) for removing trim waste (24) by suction as recited in one of the preceding claims, characterized in that the closing element (44) is actuable by a driving element (48).
6. The device (30) for removing trim waste (24) by suction as recited in claim 4, characterized in that the closing element (44) is controllable or regulable by a driving element (48), which has a control unit assigned thereto for processing measurement data from the flow velocity meter (50).
7. The device (30) for removing trim waste (24) by suction as recited in one of the preceding claims, characterized in that the apparatus (34) for producing an air flow (32) includes a pump or an impeller.
8. A printingsubstrate processing machine (10), characterized by at least one device (30) for removing trim waste (24) by suction as recited in one of the preceding claims.
9. The printingsubstrate processing machine (10) as recited in claim 8, characterized in that the printingsubstrate processing machine is a rotary offset press or a folding apparatus of a rotary offset press.
10. A method for removing trim waste (24) by suction in a printingsubstrate processing machine (10), in which an apparatus (34) produces an air flow (32) through at least one suction opening (26) into an air duct (28), thereby causing the trim waste (24) to arrive in the air duct (28), characterized in that the size of the at least one additional opening (42) of the air duct (28) is adjusted in such a way that the apparatus (34) is operated at a constant load.
Description:
DEVICE AND METHOD FOR REMOVING TRIM WASTE BY SUCTION IN A PRINTING-SUBSTRATE PROCESSING MACHINE

[0001] The present invention is directed to a device for removing trim waste by suction in a printing-substrate processing machine, including at least one air duct having at least one suction opening and one apparatus for producing an air flow through the suction opening into the air duct, the air duct having at least one additional opening. The present invention is also directed to a method for removing trim waste by suction in a printing-substrate processing machine, in which an apparatus produces an air flow through at least one suction opening into an air duct, thereby causing the trim waste to arrive in the air duct.

[0002] When printing substrates, in particular paper or cardboard, are processed in printing-substrate processing machines, especially rotary offset presses or folding apparatuses of rotary offset presses, cuts or preforations are frequently made, which produce trim waste, shavings, trim strips, a selvage edge, an edge, printing substrate fragments, dust or similar waste products, referred to in the following simply as trim waste, which must be removed from the machine processing location. For this purpose, devices which utilize air flows are often employed to remove the trim waste by suction.

[0003] From the German Application DE 101 06 672 Al, for example, a device of this kind is known for removing trim waste by suction, which is assigned to a web slitter of a rotary offset press. The device includes a negative air-pressure source which is able to be connected by a valve arrangement having a plurality of switching states to a number of suction connecting pieces, so that the suction connecting pieces alternately exert a suction power or are switched off.

[0004] Another device for removing trim waste by suction is known from the document GB 420,899. In addition to a suction opening, the device discussed in this document has an air duct, which includes a multiplicity of additional openings that are partially covered with gauze or with a metal screen and that are used for producing a turbulent flow in the air duct. [0005] Especially when removing trim waste, in particular selvage edges, by suction, produced by trimming a side of a web substrate, in particular of a paper web, care should be taken to ensure that the flow velocity of the suctioned air is greater than the linear velocity (translational velocity) of the printing substrate, in particular of the paper web. The trim waste or selvage edges must be carried by the air flow and/or tensioned, in particular at the cutting point, without fluttering, while the edges of the web substrate are simultaneously tensioned during the trimming operation. The trim waste or selvage edges are supported and removed by suction substantially in a straight line and in parallel to the moving direction of the web substrate, since they are otherwise subject to an upwarping and powerful shearing forces act at the cutting point. A direct tensile action at the cutting point is also avoided.

[0006] Since there is a difference in the web tension upstream and downstream from the trimming cut (the web width is reduced by the trim waste or the selvage edge), a force acts on the web substrate at the cutting point, with the result that tearing, cracking, stretching, and buckling or the like can occur. This force can be so strong that it causes the trim waste or the selvage edge to be curled, crimped, or torn.

[0007] If trim waste or selvage edges produced by trimming a side of a web substrate are removed by suction by a device that is operated at a constant suction power, for example, a suction power that is set to the maximum production speed of the machine, there is a significant risk of the trim waste tearing off or becoming completely severed from the web. The result, on the one hand, is that, under certain circumstances, the trim waste no longer arrives in the device, thereby contaminating the operating environment, and, on the other hand, that damage to the trimmed web substrate can occur. It is clear that the risk becomes greater as the maximum production speed increases.

[0008] The objective of the present invention is, therefore, to devise a device for removing trim waste by suction, which, when working with a substantially constant loading of an apparatus for producing an air flow through a suction opening into an air duct, permits the suction power, i.e., the intensity of the air flow to be varied.

[0009] This objective is achieved in accordance with the present invention by a device for removing trim waste by suction in a printing-substrate processing machine having the features as set forth in claim 1. Advantageous refinements of the present invention are delineated in the dependent claims.

[0010] A device according to the present invention for removing trim waste by suction in a printing-substrate processing machine includes at least one air duct having at least one suction opening and one apparatus for producing an air flow through the suction opening into the air duct, the air duct having at least one additional opening which has a closing element such that the size or surface area of the additional opening is able to be variably adjusted, preferably even infinitely variably adjusted, in particular to a number of different sizes.

[0011] In particular, the device according to the present invention may be assigned to a web slitter, preferably to a side-trimming device, as already mentioned above. The printing substrate may be a web substrate, a paper web or a cardboard web, in particular. The printing-substrate processing machine may, in particular, be a web— fed press, a rotary offset press, or a folding apparatus of a rotary offset press.

[0012] It is especially beneficial that the adjustability of the suction power in the device according to the present invention enables the air flow to be controlled as a function of the particular requirement. In particular, the air flow, thus the action off" force on the trim waste and the printing substrate, may be set to a minimally required rate Ln accordance with the machine speed. Thus, in a slow machine operation, the risk of severing the trim waste or of damaging the printing substrate is lessened.

[0013] The air duct may have one or a plurality of duct sections and, in particular, have hoses, metal connecting pieces, suction connecting pieces, funnels, scoops or the like. The term "air ducts" used in this description is understood to not only include ducts in the narrow sense, but also the entire system of different hollow spaces in the device according to the present invention provided with a negative air pressure, i.e., with an air flow.

[0014] In the device according to the present invention for removing trim waste by suction, the additional opening may be closable. The size of the additional opening may be reduced to zero. In one specific embodiment of this kind, the closing element may also be described as a seal.

[0015] In one advantageous specific embodiment of the device, the air duct includes a substantially t-tubular end piece (also to be denoted as suction connecting piece), in whose first leg the suction opening is located and in whose second leg the additional opening is located. The t-tubular end piece may be round, prismatic, rectangular or polygonal. In one concrete specific embodiment, the actually selected form of the air duct, in particular of the t-tubular end piece, depends on the available space, its size and geometry.

[0016] In addition or alternatively thereto, the device may also incl~ude a flow velocity meter, preferably a Pitot tube.

[0017] In one advantageous specific embodiment of the device, the; closing element or the seal of the additional opening is actuable by a driving element. The driving element may be electrical or pneumatic, in particular, it may be a motor.

[0018] In one especially beneficial specific embodiment of the device, the closing element is controllable or regulable by a driving element, which has a control unit assigned thereto for processing measurement data from the flow velocity meter.

[0019] The controlling or regulating control unit may also have an interface to the machine control or constitute a part of the machine control.

[0020] The apparatus for producing an air flow in the device according to the present invention may include a pump or an impeller. The apparatus may be a. turbopump, a vacuum pump, a negative air-pressure source, or a propeller.

[0021] A printing-substrate processing machine may include a device according to the present invention. In other words, a printing-substrate processing macϊiine according to the present invention includes at least one device for removing trim waste by suction in accordance with this description. The printing-substrate processing machine is preferably a rotary offset press or a folding apparatus of a rotary offset press, but may also be a folding machine for sheet substrates or a sheet-fed printing press. A rotary offset press may be a commercial web press or a newspaper printing press. A rotary offset press includes at least one reel changer, a number of printing units having upper and lower printing units (typically four printing units) which print on both sides of the web substrate, a chilling tower, a dryer, and a folding apparatus in which the web substrate is cut and folded into a plurality of signatures, copies or booklets.

[0022] Also included in the context of the inventive idea is a method for removing trim waste by suction in a printing-substrate processing machine. In the method according to the present invention, an apparatus produces an air flow through at least one suction opening into an air duct, thereby causing the trim waste to arrive in the air duct. The size of the at least one additional opening of the air duct is adjusted in such a way that the apparatus is operated at a constant load. The load of the apparatus is, in particular, the air volume, the output power, i.e., the pump power. Thus, the flow velocity through the suction opening and through the air duct is advantageously adjustable.

[0023] Further advantages, advantageous specific embodiments and refinements of the present invention are described with reference to the following figures, as well as their descriptions. Specifically, they show:

[0024] Figure 1 a schematic representation of a web slitter for trimming a side of a web substrate for elucidating the device according to the present invention for removing trim waste by suction; and

[0025] Figure 2 a schematic representation of an end piece of an advantageous specific embodiment of the device according to the present invention for removing trim waste by suction.

[0026] Figure 1 schematically depicts a web slitter for trimming a side of a web substrate, preferably a paper web, for clarifying the device according to the present invention for removing trim waste or a selvage edge by suction. In a printing-substrate processing machine 10, in particular a rotary offset press, a web substrate 12 is moved in a feed direction 14. A knife trimmer 16 cooperates with a knife contact cylinder 18 to act on web substrate 12, in that web substrate 12 runs or is passed through both, and knife trimmer 16 and knife contact cylinder 18 are driven in counter-rotation. The distance between knife trimmer 16 and knife contact cylinder 16 is variable, as indicated by the double arrow, thereby enabling the thickness of the web substrate and the type of printing substrate (havirtg different trimming properties) to be considered, to ensure that an optimal cut is made. Knife contact cylinder 18 has a supporting surface 20 for web substrate 12 and a trim- waste supporting surface 22 for trim waste 24 or the selvage edge that is severed from the edge of web substrate 12. A suction opening 26 of an air duct 28 of a specific embodiment of a device according to the present invention for removing trim waste by suction (see also Figure 2) is positioned in such a way that the suction action of the air flow into air duct 28 causes severed trim waste 24 to pass through suction opening 26 and arrive in the device. A^s is immediately apparent to one skilled in the art, devices of this kind may be placed on both. sides of web substrate 12 (not shown here in Figure 1 merely for the sake of simplifying the representation).

[0027] Figure 2 is a schematic representation of an end piece 36 of one advantageous embodiment of device 30 according to the present invention for removing trim waste by suction. An air flow 32 is produced in device 30 according to the present invention by an apparatus 34. In this specific embodiment, device 30 includes a t-tubular end piece 36 having a first leg 38 and a second leg 40. First leg 38 forms a connecting piece having a suction opening 26; second leg 40 has an additional opening 42, whose size or cross- sectional area is variably adjustable by a closing element 44. Closing element 44 is movable in moving direction 46 by a driving element 48, enabling a maximum and a minimum size (and also a complete seal), as well as infinitely variable intermediate sizes of additional opening 42 to be adjusted.

[0028] In addition, a flow velocity meter 50, here a Pitot tube filled with water, is installed in first leg 38. The velocity of the air flow is able to be easily determined from level difference 52 of the water in the communicating columns of the Pitot tube: In the steady state, a force equilibrium results in the columns. The dynamic pressure, that is produced by the flow and that is proportional to the square of the velocity of the gas or of the air in the flow, is equal to the difference in the values of the hydrostatic pressure prevailing in the columns, resulting from level difference 52. Thus, the Pitot tube may be calibrated in a simple manner for purposes of measuring velocity. It is self-evident that, clearly associated with each velocity, is also a volume of gas or air flowing through the first leg in one unit of time. To operate the device in accordance with the present invention, it is provided at this point that apparatus 34 for producing air flow 32 have a substantially constant load, in particular air volume per unit of time. The larger the size of additional opening 42 is adjusted in second leg 40, the more air volume arrives per unit of time through second leg 40 into apparatus 34. Air flow 32 consequently decreases in first leg 38. At this point, the operator or the machine control of printing-substrate processing machine 10 may utilize the flow velocity measurement obtained from flow velocity meter 50 to effect a control or regulation to a specific value. The size of additional opening 42 is varied by driving element 48 until the air flows at the desired or required velocity through suction opening 26 into first leg 38. In particular, the desired or required value of the velocity may be a function of the operating speed of printing-substrate processing machine 10, in particular of the velocity of web substrate 12 in feed direction 14. At a low feed velocity, a low flow velocity of air flow 32 is adjusted. In other words, the Pitot tube is used for calibrating, controlling and regulating the motor, i.e., for optimizing the adjustment or function of the removal by suction. REFERENCE NUMERAL LIST

10 printing-substrate processing machine 12 web substrate 14 feed direction 16 knife trimmer 18 knife contact cylinder 20 supporting surface 22 trim- waste supporting surface 24 trim waste 26 suction opening 28 air duct 30 device for removing trim waste by suction 32 air flow 34 apparatus for producing an air flow 36 t-tubular end piece 38 first leg 40 second leg 42 additional opening 44 closing element 46 moving direction 48 driving element 50 flow velocity meter 52 level difference