Patent Publication Number: US-7591615-B2

Title: Sheet material cutting machine with vacuum cleaning system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   Not Applicable 
   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH 
   Not Applicable 
   REFERENCE TO MICROFICHE APPENDIX 
   Not Applicable 
   FIELD OF THE INVENTION 
   The present invention generally relates to sheet material cutting machines of the type having work material supporting bristle beds and, more particularly, to such machines having systems for removing loose fibers, threads, small pieces of material, and/or other debris which tend to collect in spaces between bristles of the bed. 
   BACKGROUND OF THE INVENTION 
   Machines for cutting sheet material such as fabric, cloth, vinyl, leather and the like typically have a work material supporting bed comprising a plurality of generally vertically extending bristles. Upper free ends of the bristles define a work material supporting surface so that the bed may be penetrated by a cutting tool such as a reciprocating knife, a rotating drill, or the like that is used to cut the sheet material. As shown in  FIG. 1 , one or more sheets  1  of the work material  2  to be cut are typically stacked on the supporting surface  3  and air  4  is passed downwardly through the bed  5  to create vacuum pressure at the supporting surface  4  which holds and compresses the work material  2  in position. If needed the work material  2  is covered with a layer of air impervious material  6  to create the vacuum pressure. Cutting debris  7  tends to collect between the bristles  8  of the bed  5  and should be removed to maintain efficient performance of the machine. The debris  7  can hinder operation of the cutting tool and/or impede air flow through the bed  5 . 
   One method of cleaning the debris from the bristles has been to periodically remove the bristle bed from the machine, such as between work shifts. Bed portions are placed in a cleaning apparatus which removes debris. One such apparatus cleans the bed portions by applying sharp impact forces to the bed portions to shake the accumulated debris from the bristles. For examples of such cleaning apparatus see U.S. Pat. Nos. 4,224,711 and 5,065,469, the disclosures of which are expressly incorporated herein in their entirety by reference. These cleaning apparatus have the disadvantage that to achieve cleaning of the bristle bed, bristle units must be separated from the cutting machine, cleaned by the cleaning apparatus remote from the cutting machine, and reassembled with the cutting machine. This process requires a great deal of time and labor. 
   Attempts have been made to provide a cleaner capable of cleaning the bristle bed while the bristle bed remains assembled to the cutting machine. One such cleaner includes a plurality of rotary blades and a vibrator to dislodge the debris and a vacuum device to remove dislodged debris. The cleaner replaces the cutting tool on a cutter carriage or is carried by its own carriage. See U.S. Pat. No. 5,361,453, the disclosure of which is expressly incorporated herein in its entirety by reference. Another such cleaner is for a conveyer-type cutting machine and includes pins at an underside of the conveyer that comb the bristles and a vacuum device to remove dislodged debris. The vacuum system for the bed is diverted to the cleaner during cleaning. See U.S. Pat. No. 5,412,836, the disclosure of which is expressly incorporated herein in its entirety by reference. While these cleaners may be capable of cleaning the bristle bed while the bristle bed remains assembled to the cutting machine, they require the cutting machine to be in a down condition. 
   Attempts have been made to provide a cleaner for cleaning the bristle bed while the cutting machine remains operational. One such cleaner is for a conveyor type cutting machine and delivers jets of compressed air to dislodge debris at an underside of the conveyor so that the debris falls down to the ground. See U.S. Pat. No. 6,058,556, the disclosure of which is expressly incorporated herein in its entirety by reference. Another such cleaner is also for a conveyor type cutting machine but uses a vacuum device to remove debris. See U.S. Pat. No. 6,732,854, the disclosure of which is expressly incorporated herein in its entirety by reference. While these cleaners may be capable of cleaning the bristle bed while the cutting machine remains operational, they essentially clean portions of the conveyor-type bristle bed while they are “off-line.” Thus, these cleaners cannot be utilized with non-conveyor type cutting machines. Additionally, debris is not removed until cutting of that portion of the work material is complete. Thus, cutting operations subsequent to initial cutting operations on a particular sheet of work material may be affected by debris created by prior cutting operations. 
   There is a desire to cut work material with a “zero buffer”, that is, without a gap between the end products. A zero buffer results in less wasted work material and thus decreases costs for the end products. To obtain a zero buffer, however, the work material must be precisely positioned and held in place with even vacuum pressure and operation of the cutting tools cannot be hindered by cutting debris. Accordingly, there is a need in the art for an improved sheet material cutting machine which can remove cutting debris as the work material is cut. 
   SUMMARY OF THE INVENTION 
   The present invention provides a sheet material cutting machine which attempts to address one or more problems of the related art. According to the present invention, a sheet material cutting machine comprises, in combination, a bristle bed with generally vertically extending bristles having free ends defining a support surface for supporting sheet material to be cut and a carriage movable over the bristle bed and carrying at least one cutting tool to selectively cut the sheet material. A vacuum cleaning system provides vacuum at the carriage to remove cutting debris as the cutting tool is cutting the sheet material. 
   According to another aspect of the present invention, a sheet material cutting machine comprises, in combination, a bristle bed with generally vertically extending bristles having free ends defining a support surface for supporting sheet material to be cut and a carriage movable over the bristle bed and carrying at least one cutting tool to selectively cut the sheet material. A vacuum cleaning system provides vacuum at the cutting tool to remove cutting debris as the cutting tool is cutting the sheet material. 
   According to yet another aspect of the present invention, a sheet material cutting machine comprises, in combination, a bristle bed with generally vertically extending bristles having free ends defining a support surface for supporting sheet material to be cut and a carriage movable over the bristle bed and carrying at least one hollow drill to selectively cut the sheet material. A vacuum cleaning system provides vacuum through the hollow drill to remove cutting debris as the hollow drill is cutting the sheet material. 
   From the foregoing disclosure and the following more detailed description of various preferred embodiments it will be apparent to those skilled in the art that the present invention provides a significant advance in the technology of sheet material cutting machines. Particularly significant in this regard is the potential the invention affords for providing a high quality, reliable cutting which removed cutting debris as the material is cut. Additional features and advantages of various preferred embodiments will be better understood in view of the detailed description provided below. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and further features of the present invention will be apparent with reference to the following description and drawings, wherein: 
       FIG. 1  is a diagrammatic view of cutting debris lodged in bristles of a bristle bed; 
       FIG. 2  is a perspective view of a sheet material cutting machine according to a first embodiment of the present invention; 
       FIG. 3  is an enlarged elevational view, in cross-section, of cutting tool assembly of the sheet material cutting machine of  FIG. 2 , wherein vacuum is applied to a hollow drill to remove cutting debris; 
       FIG. 4  is an enlarged elevational view, partially in cross-section, of a drill assembly of the cutting tool assembly of  FIG. 3 ; 
       FIG. 5  is a diagrammatic view of a vacuum cleaning system of the sheet material cutting machine of  FIG. 2 ; 
       FIG. 6  is an enlarged perspective view of a variation of the cutting tool assembly of  FIG. 3 , wherein a cooling system is provided; 
       FIG. 7  is a fragmented perspective view of a sheet material cutting machine according to a second embodiment of the invention, wherein vacuum is applied to a chamber formed at a press foot of a cutting tool assembly to remove cutting debris; and 
       FIG. 8  is a fragmented perspective view of a sheet material cutting machine according to a third embodiment of the invention, wherein one cutting tool has vacuum applied to a hollow drill similar to the first embodiment of the present invention and another cutting tool has vacuum applied to a chamber formed at a press foot similar to the second embodiment of the present invention. 
   

   It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various preferred features illustrative of the basic principles of the invention. The specific design features of a sheet material cutting machine as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes of the various components, will be determined in part by the particular intended application and use environment. Certain features of the illustrated embodiments have been enlarged or distorted relative to others to facilitate visualization and clear understanding. In particular, thin features may be thickened, for example, for clarity or illustration. All references to direction and position, unless otherwise indicated, refer to the orientation of the sheet material cutting machine illustrated in the drawings. In general, up or upward generally refers to an upward direction within the plane of the paper in  FIG. 3  and down or downward generally refers to a downward direction within the plane of the paper in  FIG. 3 . 
   DETAILED DESCRIPTION OF CERTAIN PREFERRED EMBODIMENTS 
   It will be apparent to those skilled in the art, that is, to those who have knowledge or experience in this area of technology, that many uses and design variations are possible for the improved sheet material cutting machines disclosed herein. The following detailed discussion of various alternative and preferred embodiments will illustrate the general principles of the invention with reference to a non-conveyor or stationary type cutting machine for cutting fabric, cloth, vinyl, leather, or the like. Other embodiments suitable for other applications of the invention will be apparent to those skilled in the art given the benefit of this disclosure, such as, for example, a conveyer-type sheet material cutting machine or the like. 
   Referring now to the drawings,  FIG. 2  shows a sheet material cutting machine  10  according to a preferred embodiment of the present invention. The illustrated sheet material cutting machine  10  includes a bristle bed  12  with generally vertically extending bristles  14  having upper free ends defining a supporting surface  15  for supporting a lay-up of sheets  18  of work material  20  to be cut such as fabric covered by a sheet of air-impermeable material  22 , a carriage  24  movable over the bristle bed  12  and carrying at least one cutting tool  26  to selectively cut the work material  20 , and a vacuum cleaning system  28  which provides vacuum at the carriage  24  to remove cutting debris as the cutting tool  26  is cutting the sheets  18  of material  20 . 
   The illustrated cutting machine  10  includes an upwardly facing supporting surface  16  provided by the bristle bed  12 . The illustrated bristle bed  12  is stationary relative to ground and is comprised of a large number of the generally vertically extending bristles  14 , the upper free ends of which define the supporting surface  16 . The supporting surface  16  of the illustrated bed has a width dimension parallel to the illustrated Y-coordinate direction and a length dimension parallel to the illustrated X-coordinate direction. The illustrated carriage  24  includes a main or X-direction carriage  30  and a cutting tool or Y-direction carriage  32 . The main carriage  30  extends above and across the supporting surface  16  parallel to the width dimension of the supporting surface  16  and is movable in the X direction along the length of the supporting surface  16 . The main carriage  30  is supported at both ends by rails  34  having suitable racks and guide surfaces for supporting the main carriage  30  for movement there along under the influence of an X drive motor powering pinions that engage racks on the rails. A pair of cutting tool assemblies  36  each having a cutting tool  26  in the form of a rotatable drill is mounted on the illustrated cutting tool carriage  32 . It is noted that other quantities of cutting tool assemblies  36  can be carried by the cutting tool carriage  32  and/or the cutting tools  26  can be of other types such as, for example, reciprocating knives, or combinations of different types of cutting tools  26 . The cutting tool carriage  32  is moved in the Y-coordinate direction along the length of the main carriage  30  by a Y drive motor so that by coordinated movements of the main carriage  30  in the X direction and the cutting tool carriage  32  in the Y direction, the cutting tool  26  may be moved along any desired line or location of cut relative to the work material  20 . This movement of the carriages  30 ,  32  and related operations of the cutting tool assemblies  36  are controlled in a conventional manner by a main controller  40 . It is noted that the cutting tool assemblies  36  can alternatively be carried by any other suitable type of carriage  24  within the scope of the present invention. 
   As described in U.S. Pat. No. 4,205,835, the disclosure of which is expressly incorporated herein in its entirety by reference, the bristle bed  12  is preferably comprised of a plurality of smaller bristle units or squares  42 , which may be made of injection molded plastic, each of which has a base portion and a plurality of the bristles  14  extending upwardly therefrom. The bristle units  42  rest on a grid  44  below which are a number of vacuum chambers each extending across the width of the bristle bed  12  and arranged successively along the length of the bed  12  with each such vacuum chamber being connectable to a main air duct  46  through operation of associated valve operating members  48 . 
   The main air duct  46  is selectively connected through a selector valve assembly  50  to either the vacuum port  52  or the pressure port  54  of an air pump or turbine  56 . When the main air duct  46  is connected to the vacuum port  52  of the air pump  56 , each vacuum chamber can be connected to vacuum pressure by pushing its associated operating member  48 . The illustrated cutting machine  10  has a cam  58  carried by the main carriage  30  which operates the valve operating members  48  so that vacuum pressure is applied to the vacuum chambers located beneath or close to the cutting tool assemblies  36  so as to compress and hold down the work material  20  primarily in the vicinity of the cutting tool assemblies  36 . When the main air duct  46  is connected to the pressurized air port  54  of the air pump  56 , pressurized air may be applied to the bristle bed  12  to form an air cushion between the supporting surface  16  and the work material  20  to aid in sliding the work material  20  onto and off of the supporting surface  16 . 
   As best shown in  FIG. 3 , each of the illustrated cutting tool assemblies  36  include a foot press assembly  60 , a cutting tool  26  such as the illustrated hollow drill  61 , and an actuation or drill assembly  62  for operating the cutting tool  26  and supported by the foot press assembly  60 . The illustrated foot press assembly  60  includes a foot press  64  adapted to engage and press the work material  20  during cutting. The illustrated foot press  64  has a central opening  66  for passage of the cutting tool  26  therethrough to cut the work material  20 . Spaced above the foot press  64  is a foot press cylinder  68  that is secured to the foot press  64  by a pair of vertically extending and laterally spaced-apart guides or rods  70 . The foot press cylinder  68  is sized and shaped for supporting the drill assembly  62  as described in more detail hereinafter. The illustrated hollow drill  61  is tubular shaped having a central, axially extending passage  72  therethrough. The lower end of the hollow drill  61  is provided with a circular shaped cutting edge  74  for cutting a circular-shaped opening in the work material  20 . The hollow drill  61  can be of any suitable size. 
   As best shown in  FIG. 4 , the illustrated drill assembly  62  includes a cylinder  76  adapted to be secured within the foot press cylinder  68 . A piston  78  is provided within and secured to the cylinder  76  and the cylinder  76  is provided with upper and lower end caps  80  to seal the interior space therebetween so that a compressed fluid or the like can be inserted into the cylinder  76  to selectively move the piston  78  in a downward direction as described in more detail hereinafter. The lower end of the piston  78  is secured to a press foot support  82 . The press foot support  82  is provided with openings  84  for closely receiving the rods  70  of the press foot assembly  60  to support the lower end of the piston  78  as it moves in the vertical direction. 
   A hollow shaft or rod  86  having an axially extending passage  88  therethrough extends through the piston  78  and is rotatably supported by the piston  78 . Suitable bearings or bushings  90  are provided so that the hollow shaft  86  can rotate about its vertical axis. A lower end of the hollow shaft  86  is provided with a collet and nose piece  92  suitable for releasably securing the hollow drill  61  thereto so that the hollow drill  61  is coaxially rotatable about its central axis along with the hollow shaft  86 . Fixed to an upper portion of the hollow shaft  86  is pulley  94  that cooperates with a belt  96  of a drive means. When the drive means is activated to drive the belt  96 , the belt  96  rotates the pulley  94  which rotates the hollow shaft  86  connected thereto. Rotation of the hollow shaft  86  rotates the hollow drill  61  to cut a circular-shaped opening in the work material  20  when the hollow drill  61  engages the work material  20 . 
   A spring member  98  is provided about the upper end of the piston  78  and acts between the upper end of the cylinder  76  and the pulley  94  to resiliently bias the hollow shaft  86  and the hollow drill  61  upward to a first or retracted position. When compressed air or other suitable fluid is injected into the cylinder  76  above the piston ring, the piston  78  is driven in a downward direction, along with the hollow shaft  86  and the hollow drill  61  until the hollow shaft  86  and the hollow drill  61  are in second or extended positions wherein the cutting edge  74  engages the work material  20  to cut the opening. When the compressed air is released, the spring member  98  resiliently returns the piston  78 , along with the hollow shaft  86  and the hollow drill  61 , in an upward direction toward the retracted position. 
   A mounting bracket  100  is provided for securing a hose connector or adaptor  102  in a fixed position which receives an upper end of the hollow shaft  86 . The illustrated adapter  102  is generally tubular shaped with the upper end of the hollow shaft  86  extending therein. The mounting bracket  100  and the adapter  102  are sized and shaped so that the hollow shaft  86  can rotate relative to the adapter  102  while a tube or hose  104  of the vacuum cleaning system  28  is secured to the adapter  102  to provide air and debris flow between the tube  104  and the hollow shaft  86  as described in more detail hereinafter. The hose  104  is preferably soft or flexible so that the carriages  30 ,  32  can move as desired but can alternatively be of any other suitable type. 
   As best shown in  FIG. 5 , the illustrated vacuum cleaning system  28  includes a pipe or hose assembly  106  connecting the upper end of the hollow shafts  86  with a filter  108  having a suitable debris catching basket  110  which is in turn connected to the main air duct  46  with a suitable duct  111  to provide vacuum suction to the hollow drills  61 . Suitable valves  112  are provided so that the air flow from the hollow shafts  86  can be selectively opened and closed. The illustrated valves  112  are UVC gate valves suitable connected to receive compressed air and electric control signals from the controller  40 . It is noted that any other suitable valves  112  and control system can alternatively be utilized. The illustrated hose assembly  106  includes a plurality of pipe or tube sections  105  suitably connected by rubber adaptors  114  and pipe clamps  116  to complete the air and debris path between the tubes  104  and the filter  108 . The tube sections  105  are preferably rigid PVC pipe but can alternatively be of any other suitable type. It is noted that the hollow shafts  86  can alternatively be suitably connected to the filter  108  and main air duct  46  in any other suitable manner. It is also noted that the vacuum cleaning system  28  can alternatively have it own independent air pump  56  if desired. 
   In operation, the valves  112  are opened to create vacuum pressure at the lower end of the hollow drill  61  whenever the hollow drill  61  is activated to cut the work material  29 . As the hollow drill  61  cuts the work material, dust, threads, plugs and other debris is immediately sucked by the vacuum into the hollow drill  61  where it passes through to the hollow shaft  86  and then to the hose assembly  106 . Once in the hose assembly  106 , the debris passes to the filter  108  where it is caught and retained in the collecting basket  110 . When the cutting operation of the hollow drill  61  is complete, the controller  40  preferably closes the valve  112  to cut off the vacuum from the hollow drill  61 . The debris is then periodically removed from the collection basket  110  as needed. By removing the debris during the cutting operation, the debris does not become lodged within the bristles  14  of the cutting bed  12  and thus does not affect remaining cutting operations. 
   It has been found that under some conditions, the debris may stick or meld to the interior surface of the hollow drill  61  rather than freely passing through the hollow drill  61 . This appears to particularly be the case for relatively small diameter, relatively high speed hollow drills  61  and/or for cutting polymeric materials such as vinyl. As best shown in  FIG. 6 , the vacuum cleaning system  28  can further include a cooling system  118  to cool at least a portion of the debris path. The illustrated cooling system  118  includes air lines or tubes  119  operably connected to a source of pressurized air and positioned to inject a stream of cooling air onto the exterior surface of the lower end of the hollow drill  61 . In this manner, the temperature of the hollow drill  61  can be maintained at a temperature which limits the adherence of debris onto the hollow drill  61 . It is noted that any other suitable means for cooling the hollow drill  61  can alternatively be utilized. Alternatively, the internal passage  72  of the hollow drill  61  can be at least partially provided with a low coefficient of friction material to limit adherence of debris to the hollow drill  61 . 
     FIG. 7  illustrates a sheet material cutting machine  120  according to a second embodiment of the invention which is substantially identical to the first embodiment described hereinabove except that vacuum is provided through the presser foot or foot press  64  rather than directly through the cutting tool  26 . The illustrated presser foot  64  is formed to have an internal cavity  122  and the hose assembly  106  is connected directly to the presser foot  64  to selectively form a vacuum within the cavity  122 . An opening  124  is provided at the lower wall of the presser foot  64  and forming cavity  122  at the location of the cutting tool  26 , such as the illustrated hollow drill  61 , so that the vacuum pressure removes debris during the cutting operation and as the cutting tool  26  is withdrawn from the work material  20 . It is noted that the presser foot  64  and the cavity  122  can have any suitable size and shape. 
     FIG. 8  illustrates a sheet material cutting machine  126  according to a third embodiment of the invention which is substantially identical to the first and second embodiments described hereinabove except that the first cutting tool assembly  36  provides vacuum through the presser foot  64  and the second cutting tool assembly  36  provides vacuum through the cutting tool  26 . It is noted that any suitable quantity of either type of cutting tool assembly  36  can be used as desired. This embodiment illustrates that any combination of the various embodiments of the present invention can be utilized. 
   From the foregoing disclosure and detailed description of certain preferred embodiments, it is apparent that the present invention provides a vacuum cleaning system that effectively removes cutting debris during the cutting operation. Cutting debris that can hinder the cutting tools and/or inhibit a proper vacuum on the work material does not become lodged in the bristles. As a result, the work material can be cut with zero buffers to reduce wasted material. 
   From the foregoing disclosure and detailed description of certain preferred embodiments, it is also apparent that various modifications, additions and other alternative embodiments are possible without departing from the true scope and spirit of the present invention. The embodiments discussed were chosen and described to provide the best illustration of the principles of the present invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the present invention as determined by the appended claims when interpreted in accordance with the benefit to which they are fairly, legally, and equitably entitled.