1. Field of the Invention
The present invention relates generally to web printing presses and more particularly to a folder for cutting a web into signatures.
2. Background Information
Web printing presses print a continuous web of material, such as paper. The continuous web then is cut in a cutting unit of a folder so as to form signatures which can then be folded or output.
U.S. Pat. No. 5,740,709 discloses a double-cut folder. The cutting cylinders do not provide a nipping action. This device is disadvantageous in that signatures may experience a stepped cut due to motion between the first and second cut.
U.S. Pat. No. 4,957,280 discloses a folder in which a web is first cut by a cutter drum, and then is pinched between a folding drum and conveyor belts. The web not cut by the first cutter drum is then cut by saw-tooth cutter blades of a second cutter device disposed on the folder drum so as to form a cut sheet. A head end of the web cut into the sheet is pushed into gaps between a plurality of clamping claws and claw seats and clamped.
The '280 patent has the disadvantages that slip may still occur in both the web direction and in a cross-web direction owing to the fact that the nip forces between the conveyor belts and the folding drum may not be sufficient. A stepped cut thus also may occur. Cut accuracy may also suffer due to a radius effect when variable thicknesses of web pass through the folder. Moreover, the '280 patent appears to require a complicated jaw-type device to maintain proper signature control. In addition, the anvil surfaces or cutter receiver may wear out over time.
Commonly-owned U.S. patent application Ser. No. 09/435,667 filed Nov. 8, 1999 (which is not necessarily prior art to the present invention) discloses a double-cut lobed belt diverter. A first cut is made with a first cutting cylinder and then a second cut by a second cutting cylinder having cutting disks. Lobed belts pass between the cutting disks to grab the cut signatures and divert the signatures into two streams. The belts grasps the lead of the signature after the second cut and thus do not help to maintain signature control during the second cut.
An object of the present invention is to provide a device and method for reliably cutting signatures in a controlled fashion and to improve accuracy with regard to a “cut-to cut” measurement as well as print-to-cut measurement.
The present invention provides a folder having a first cutting and nipping device for partially cutting a web so as to form first cuts in the web and for nipping the web, and a second cutting and nipping device for cutting the web between the first cuts so as to form signatures and for nipping the web.
By having the web nipped between the first and second cutting devices, cut accuracy, both for cut-to-cut and print-to-cut, can be maintained at all times.
The first cutting and nipping device includes a first cutting cylinder having a nipping surface and at least one segmented cutting element having axially-spaced cutting surfaces. The nipping surface extends circumferentially between the cutting surfaces. The first cutting and nipping device also includes an anvil cylinder for forming a nip with the nipping surface and an anvil for the segmented cutting element.
The second cutting and nipping device includes a cutting cylinder having a nipping surface and at least one segmented cutting element having axially-spaced cutting surfaces. The nipping surface extends circumferentially between the cutting surfaces. An anvil cylinder forms a nip with the nipping elements and an anvil for the segmented cutting element.
The folder preferably includes a plurality of first belts and a plurality of second belts, the web being held by the first belts and second belts at the first cuts. At least one of the anvil cylinder and the cutting cylinder of the second cutting and nipping device have axially-spaced grooves between the nipping surfaces of the second cutting an nipping device, the belts passing through the grooves.
Preferably, the nipping elements and the anvil cylinder include a urethane outer coating. The urethane provides an excellent anvil and nipping surface. However, nipping surface materials other than urethane are possible.
Preferably, the cutting cylinder includes a metallic hub with the at least one segmented cutting element bolted to the hub. Urethane or another nipping material bonded to the hub then forms the rest of the cutting cylinder. The anvil cylinder also may have a metal core with a urethane or other nipping material outer surface bonded to the core.
The cutting cylinder preferably has two segmented cutting elements spaced 180 degrees apart.
The anvil cylinder preferably is indexable circumferentially so that a new anvil surface may be provided. A continuous outer layer, preferably of urethane, on the anvil cylinder is thus highly advantageous so that a new anvil surface can be presented when the anvil cylinder is indexed with respect to the cutting cylinder. The anvil cylinder thus can be operational for a longer period than traditional anvil cylinder having a specifically designed anvil area.
The center distance between the cutting cylinder and the anvil cylinder of the cutting and nipping devices preferably is adjustable to adjust the nipping function, for example to accommodate different web thicknesses. The adjustment preferably is force-loaded, for example by springs, so that the devices automatically compensates the center distance if the thickness of the material changes.
The cutting and the anvil cylinders preferably are cantilevered, to permit easy replacement of the belts.
The present invention also provides a method for cutting a web which includes the steps of partially cutting the web so as to form first cuts in the web and nipping the web as the first cuts are formed; and cutting the web between the first cuts while the web is nipped.
The present method advantageously provides a double-cut configuration which can allow for holding of web during the first and second cuts in a firm nipped position. Tension and proper placement may be maintained during the cut operation.
The present device and method is particularly advantageous for use with high-speed web printing presses, e.g. presses operating at over 2000 feet per minute, since the web and resultant signatures may be held firmly even at high speed due to the nips at the first and second cutting devices. The web and the knives thus track exactly together.
A preferred embodiment of the present invention is described below by reference to the following drawings, in which:
Web 1 after being partially cut by first cutting device 101 passes between first guide belts or tapes 5 and second guide belts or tapes 6. Each of belts 5 and 6 include a plurality of belts spaced apart in the axial direction of cutting cylinder 3 (i.e. into the page in
Web 1 then is guided by belts 5, 6 to second cutting and nipping device 102 having a cutting cylinder 10 and an anvil cylinder 20. Cutting cylinder 10 has segmented blades 19 which cuts web 1 between first cuts 44 to make a full cut 49, as shown in
The linear position of the web in the direction of web travel and the cross web direction is controlled by the non-slip boundary condition between the nip and the web. This nipping action of second cutting and nipping device 102 permits a firm grip on web 1 as each segmented blade 19 cuts web 1 between first cuts 44 (
After the second cut, signature 50 (
A urethane or other nipping material outer layer 14 is placed over hub 12, either before or after the fastening of the two parts of hub 12 together. Layer 14 thus provides a continuous smooth surface extending circumferentially from the blade edges 32. Indented areas 36 (
Anvil cylinder 20 includes an axle 26 which may be geared to the drive motor for cutting cylinder 10 to rotate at the same speed as cutting cylinder 10. An independent drive motor may also be provided. A metallic hub 22 can be bolted by bolts 22a and fastened around axle 26. A urethane or other nipping material layer 24 may be prebonded to each side of hub 22, or may be added over hub 22 once it is fastened about axle 26. Alternatively, hub 22 may be a single piece construction.
Anvil cylinder 12 (or cutting cylinder 10) preferably is indexable circumferentially so that a new anvil surface may be provided once a part of the anvil surface is worn down by the action of the blades 19. To provide the indexing, an harmonic drive may be provided.
The center distance between cutting cylinder 10 and anvil cylinder 20 is adjustable to adjust the nipping function, for example to accommodate different web thicknesses. A simple mechanical, pneumatic or hydraulic device (not shown) may be provided for this adjustment, or preferably a force-loaded automatic adjustment may occur.
Cutting cylinder 10 and anvil cylinder 20 are cantilevered, which permits easy replacement of the belts on the non-cantilevered side. A releasable bearing may be provided to support the second end.
Cutting cylinder 3 and anvil cylinder 2 may be similar in construction to cutting cylinder 10 and anvil cylinder 20, except that the nip surfaces of cutting cylinder 3 and anvil cylinder 2 do not need to accommodate any belts and are therefore preferably are continuous in an axial direction. The axial location of the cutting surfaces also alternate, as shown schematically in
By providing cutting and nip surfaces on the same cutting cylinder, a more accurate cut may be achieved. The web may be held at all times so that more accurate signature and cut formation can result. The urethane coating is particularly advantageous for providing the nipping function with the present device.
Each of the first cuts has a particular length defined by the width of cutting edges 45 (
The cutting cylinders 3, 10 may have a plurality of blades, such as 2, 3 or 4 blades spaced 180 degrees, 120 degrees or 90 degrees apart, respectively.
“Nipping surface” as defined herein is a section of the cutting cylinder extending circumferentially with respect to the cutting surfaces of the segmented blades. The nipping surface forms a nip with an anvil cylinder so as to nip the web.
The bonding of the urethane or other nipping material may take place via an adhesive, for example.
Number | Name | Date | Kind |
---|---|---|---|
2261315 | Thorsen | Nov 1941 | A |
2951410 | Brown | Sep 1960 | A |
3119312 | Henc | Jan 1964 | A |
3522762 | Sauer | Aug 1970 | A |
3686988 | Ross | Aug 1972 | A |
3866497 | Wolfberg et al. | Feb 1975 | A |
3921481 | Marcus | Nov 1975 | A |
3954034 | Broderick | May 1976 | A |
4142431 | Jespersen | Mar 1979 | A |
4249441 | Sturtz | Feb 1981 | A |
4406196 | Roncato et al. | Sep 1983 | A |
4444080 | Schulz | Apr 1984 | A |
4825739 | Pfaff | May 1989 | A |
4925521 | Asbury et al. | May 1990 | A |
4957280 | Motooka | Sep 1990 | A |
4983155 | Stobb | Jan 1991 | A |
5103703 | Littleton | Apr 1992 | A |
5107733 | Palmatier et al. | Apr 1992 | A |
5133235 | DeVito | Jul 1992 | A |
5230268 | Richter | Jul 1993 | A |
5359914 | Brown | Nov 1994 | A |
5740709 | Boston et al. | Apr 1998 | A |
5967512 | Irsik | Oct 1999 | A |
6418827 | Bussey et al. | Jul 2002 | B1 |
6435069 | Kirkpatrick et al. | Aug 2002 | B1 |
6460439 | Belanger | Oct 2002 | B2 |
6718855 | Kane | Apr 2004 | B2 |
Number | Date | Country |
---|---|---|
19927920 | Feb 2000 | DE |
0449006 | Oct 1991 | EP |