Method of cutting holes in a moving web
United States Patent [1 1 Ballard l l METHOD OF CUTTING HOLES IN A MOVING WEB Raymond Marvin Ballard, Midlothian, Va.  
 [73] Assignee: E. I. du Pont de Nemours and Company, Wilmington Deli [22] Filed: May 29, I974 [21] Appl. No: 474,435  
 [75) lnventor:  
 Primary EtummeH-Frank&#39; T. Yost 1 Apr. 8, 1975 [57] ABSTRACT A method of cutting a patterned array of holes in a moving web of flexible material is provided including the steps of:  
  moving the web in a continuous manner so that at least a portion thereof is in a substantially flattened state while moving positioning such portion of the flattened web adjacent to a series of rotating cutters having circular cutting edges such cutting edges being arranged in a patterned array in an imaginary plane parallel to the flattened portion of the web. and driving, by means of air jets, the flattened portion of the web into momentary contact with the rotating cutting edges so as to remove circular pieces of web material in a patterned array across the web.  
 Apparatus is provided for performing the above method.  
 2 Claims, 6 Drawing Figures SHEET 3 OF 3 FIG- FIG-  
 METHOD OF CUTTING HOLES IN A MOVING WEB BACKGROUND OF THE INVENTION 1. Field of the Invention This invention is a method of and apparatus for cutting holes in a flexible web of indeterminate length as it moves continuously. The web is urged or moved against continuously rotating cutters by air jets at predetermined intervals as the web moves continuously to cut substantially round holes in such web.  
 2. Description of the Prior Art It is known to make holes in a web of flexible material of indeterminate length. using cutters or perforating devices. for example. This invention is an improved method of cutting holes in such a web.  
  US. Pat. No. 3.066.554 to Hanson is exemplary of the prior art. Such patent shows an apparatus for cutting holes in thin flexible webs. The holes are cut in transverse rows. Such holes are cut in the web, while the web is at rest. by forcing the web into engagement with the rotary cutters by use of mechanical backing means.  
  US. Pat. No. 3,460.4[6 to Gilbert shows a fibrillation method wherein a fibrillatable film is passed adjacent to a rotating roll having sharp projections protruding from its surface and compressed air is impinged against the moving web forcing the moving sharp pro jections into the moving web.  
  US. Pat. No. 3,355,974 to Carmichael discloses a film perforating apparatus comprising an outer drum having holes arranged in a patterned array and an inner drum having heated pins arranged in the same patterned array so that the heated pins are advanced through the holes and through a web advancing over the surface of the outer drum to perforate the advancing web.  
  US. Pat. No. 2.748.863 to Benton discloses a heated pin perforating apparatus wherein a thermoplastic web is passed between a perforating cylinder having protruding heated pins and an anvil roll.  
  The instant invention is an improved method over these, and other known methods and apparatus in than it provides a means and method of cutting holes in a web as it moves in a novel, useful and surprising manner.  
 SUMMARY OF THE INVENTION The web cutting method and apparatus of this invention cuts holes in webs of material by use of rotary cutters that rotate at extremely high rates of speed while the web is moving. This differs from known methods of cutting webs using this type of cutter. In such methods, the rotating cutter heads are moved relative to the moving web while the web is at rest or while an atrest web is moved into engagement with the cutters. The instant invention is an improvement over these known methods in that the cutting of the web is accomplished while the web is in motion. There is no slowing of the web or stopping of the web required during the cutting step.  
  Briefly described, in this invention a patterned array of holes is cut in a moving web of flexible material by moving a portion of the web in a substantially flattened state adjacent to a series of rotating cutters having circular cutting edges and by urging such portion of the web from its flattened state into momentary contact with the rotating cutting edges so as to remove substantially circular pieces of web material in a patterned array across the web. The flattened portion of the web is moved into the cutters in predetermined sequence by air jets and. surprisingly. the holes cut are substantially circular in spite of the web movement during cutting and, equally surprising. the cutting is done effectively. without problems, while the web moves continuously, giving to the art an effective highly desired means and method of cutting holes in webs heretofore unavailable to such art.  
 BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a partial isometric view of an apparatus capable of performing the method of this invention.  
  FIG. 2 is a schematic section view of the apparatus of FIG. I taken along line 2-2 of FIG. 1.  
  FIG. 3 is a schematic view in partial section of a single hole cutting unit employed in the apparatus of FIG. 1 and FIG. 2.  
  FIG. 4 is a partial sectional view of such a single hole cutting unit shown in a non-cutting state of operation.  
  FIG. 5 is a partial sectional view of the hole cutting unit of FIG. 4 shown in its operating position wherein the web is being cut.  
  FIG. 6 is a schematic drawing of the drive arrangement for the two banks of hole cutting units shown in FIG. 1.  
 DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the Figures a moving web I is transported through an apparatus 2 of this invention by web driven rolls 3 and 4 so that there is a portion of the moving web I in a substantially flattened state between the web-driven rolls 3 and 4. While in this substantially flattened state. the moving web 1 passes between upper guide plate 5 and lower guide plate 6. Located in the upper guide plate 5 are orifice openings 7 and 8. and located in the lower guide plate 6 are orifice openings 9 and 10. which are in vertical alignment with the upper plate orifice openings 7 and 8. These groups of aligned orifices constitute the cutting positions. The apparatus basically employed to perform the actual cutting operation are the air pulse generators 11 and 12 and rotary cutters 13 and 14. These components are shown in combination in greater detail in FIGS. 3, 4, and 5.  
  Each of the air pulse generators, such as 11, consists of inner concentric tube 15 and outer concentric tube 16. The inner concentric tube 15 rotates inside of the outer concentric tube 16 at a speed in proportion to the speed of advancement of the moving web I. A lineal array of ports, such as inner air port I7, is located in a row in inner concentric tube 15 and another series of ports, such as outer air port 18, is located in a row in outer concentric tube 16. These air ports are approximately 3/16 inch in diameter and are drilled so that they are aligned with each other once in a revolution of the inner concentric tube 15. These ports, in turn, are aligned with the locations of each of the upper plate orifice openings, such as 7. A collimating nozzle 19 is located within each upper plate orifice opening 7 to concentrate the force of the compressed air as it issues from the compressed air chamber 20 and through the inner air port 17, outer air port 18, and collimating noz zle l9 and onto the surface of the moving web 1. The inner concentric tubes of each of the air pulse generators ll and 12 are geared together so that they operate 180 out of phase with each other. Each air pulse gen erator thus pulses at equal intervals in an alternating sequence. The duration of the column of compressed air issuing from the collimating nozzle 19 at each pulse is of the order of magnitude of one millisecond. The inner concentric tubes are driven perferably by a variable speed drive such as an eddycurrent clutch type of drive. The drive speed is controlled from the speed of the web-driven rolls 3 and 4 at a predetermined ratio depending on the desired pattern. Such electronic drives are well known in the art. For example. one such drive uses a direct-current tachometer generator operated from the web-driven roll 4 to supply a tachometer signal to the variable speed drive for the inner concentric tubes. The inner concentric tube drive would thus follow the speed of the web-driven rolls at a predetermined ratio.  
  The moving web 1 is supported by the lower guide plate 6 so that the moving web is supported approxi mately OBIS-inch above a lineal array of rotary cutters. such as [3. The rotary cutter locations are aligned in two rows with the collimating nozzles. upper guide plate orifice openings. and lower guide plate orifice openings. and lower guide plate orifice openings.  
  Rotary cutters which may be used in an apparatus of this invention include those ofthe type shown in British patent 474.894 and in U.S. Pat. No. 3.066.554 to Hanson. which patents are incorporated by reference in this application.  
  The rotary cutters preferably have fluted cutting sur faces and are driven at a rotational speed of about 30,000 rpm. in normal operation, as shown in FIG. 5, a jet of compressed air issues from the collimating nor. zle 19 for a one-millisecond duration. This deflects the moving web 1 contained within the lower plate orifice opening it] and pushes this section or portion of moving web against the constantly rotating rotary cutter 13. This causes a hole to be cut into the moving web I in /6 of a revolution of the rotary cutter, which is within about a %-millisecond duration. The web is caused to travel about 0.020-inch in one millisecond so that the cut hole is slightly elongated as produced but appears as a perfectly round hole to the eye.  
  The preferred drive arrangment for the rotary cutters is shown in FIGS. 3 and 6. The rotary cutters are preferably driven in groups of 15 units. The cutter assem blies are arranged in two rows and staggered so that there are eight in one row and seven in the next row. in the configuration shown. the rotary cutters are belt driven by drive belt 21 at a speed of 3 l .000 rpm. from jacl-tshaft 22. The speed ratio of the jackshaft drive pulley 23 to the rotary cutter drive pulley 24 is 3 to 1. The rotary cutter drive motor 25 is an induction motor op erating at 3.450 rpm. This motor drives the jackshaft 22 at a 3 to 1 ratio via the motor drive pulley 26 and the jackshaft driven pulley 27. Thus. there is an overall 9 to 1 speed increase from the output shaft ofthe rotary cutter drive motor 25 to the rotar cutter 13.  
  Preferably. each cutter is rotated at a rotational speed (in revolutions per minute) at least equal to 600 times the lineal speed (in feet per minute) of the moving web divided by the number of flutes (or teeth) in the cutter.  
  The individual circles cut out of the moving web 1 are removed by the waste removal duct 28 shown in FIG. 2. This duct is connected to a vacuum system to form a pneumatic conveying system for the waste pieces from the formed holes. This waste removal can also be advantageously located between the two rows of cutters below the moving web. In this arrangement the pulses of compressed air combined with the presence ofa vacuum at the entrance of the waste removal duct, cause the circular cuttings to be removed via the waste removal duct. These cuttings pass through the material handling fan that is connected to the waste removal duct and are discharged directly into a waste bin having a screen-type air/product separator.  
  Many variations can be made in the pattern of holes produced by an apparatus and using the method of this invention. The hole size can be varied from about a VB-TITCh diameter to about a l /-inch diameter opening by using various sizes of rotary cutters. The pattern across the web can be varied by the predetermined lo cation of the cutting positions in a lineal array across the web. The pattern in the machine direction of the moving web is varied by changing the speed of rotation of the inner concentric tube of the air pulse generator. Such variations can also include a pattern of a group of holes followed by a portion of uncut web and then another group of holes. All of this type of pattern design are controlled by the rotational speed control of the inner concentric tube which controls the air pulse repetition rate. A portion of uncut web may be produced by shifting the inner concentric tubes axially so that the air ports 17 do not align with the outer air ports 18 at any time during a revolution of the inner tube.  
  It is seen. then, that the apparatus of this invention is capable of performing a useful. novel method of cutting holes in a moving web including the steps of;  
 moving the web in a continuous manner so that at least a portion of the web is in a substantially flattened state while moving;  
 positioning the portion of the moving web in the flattened state adjacent to a series of rotating cutters having circular cutting edges that are arranged in a patterned array in an imaginary plane parallel to the portion of the web that is in a substantially flattened state; and  
 urging a transverse portion of the flattened web from its flattened state into momentary contact with the rotating cutting edges so as to remove circular pieces of web material in a patterned array across the web.  
 I claim:  
  1. A method of cutting a patterned array of holes in a moving web of flexible material including the steps of:  
 moving the web in a continuous manner so that at least a portion of the web is in a substantially flattened state while moving,  
 positioning the portion of moving web in the flattened state adjacent to a series of rotating cutters having circular cutting edges. such cutting edges being arranged in a patterned array in an imaginary piane parallel to the flattened portion of the web, and  
 driving a transverse portion of the web from its flattened state into momentary contact with the rotat&#39; ing cutting edges so as to remove circular pieces of web material in a patterned array across the web.  
 2. A method of cutting a patterned array of holes in 6 the portion of the web that is in a substantially flattened state; and urging, by means of air jets, a transverse portion of the flattened web into momentary contact with the rotating cutting edges so as to remove circular pieces of web material in a patterned array across the web