Abstract:
A cutting tool assembly that includes a holder that supports a blade for use with cutting tables. At least one roller is attached to the holder and extends beyond a perimeter of the holder in a direction that is normal to an axis of rotation of the roller. The blade extends from the holder in a common direction with the roller and includes a cutting edge that is oriented in a direction that is generally normal to the axis of rotation of the roller. During a cutting process, the roller maintains the position of the material with respect to the sharpened edge of the blade.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to cutting table cutters and, more specifically, to a cutting tool having a bladed cutting tool and at least one roller that maintains the position of a material being cut relative to the blade during cutting operations. 
         [0002]    Many manufacturers of a wide variety of parts in a variety of industries are familiar with automated CNC cutting tables. Commonly, a material from which a part is to be produced or cut is placed upon a cutting table. A computer controls movement of a cutting tool relative to the material. One or more of the table, the material, and/or the cutting head is moved in a computer controlled manner so as to maximize the number of parts that can be generated from the available base material. Many appreciate the ability of such systems to produce a variety of parts, from a variety of materials, and in a quality, repeatable, and economic manner. 
         [0003]    A number of cutting tool assemblies are available for use with such automated cutting systems. Such cutting tool assemblies are provided in various configurations and have various constructions that are intended to improve cutting efficiency and cut quality as a function of the material being cut as well as specific aspects of the cutting process, such as cut turn radii and the like. Many of these tools can be classified in several general categories. One such category includes those tool assemblies wherein a cutting blade reciprocates in a sawing motion during a cutting operation.  FIG. 7  shows a cutting tool assembly  10  indicative of another category of cutting tools; those tools equipped with a stationary knife  12 . As shown in  FIG. 7 , knife  12  is oriented in a tangential direction relative to a cut direction, indicated by cutting edge  22 . Such tools commonly include a mount body  14  that is securable to a moveable mandrel of a cutting table by a fastener  16 . A fastener  18  and a support block  20  secure knife  12  to body  14 . 
         [0004]    Cutting tool assembly  10  is commonly used for cutting a variety of single ply materials. Such an assembly has been particularly accepted for cutting difficult to cut materials such as pre-pregnated composite materials, such as carbon fiber and/or plastic based materials. Such materials have a variety of applications including the formation of a number of bicycle components including frame and/or accessory structures. 
         [0005]    When cutting such generally rigid materials, knife  12  is generally formed of a carbide material so as to maintain a useable cutting edge  22  for a number of cutting cycles. A shoe or pressure foot  24  is secured by a fastener  26  to mount body  14  at a position proximate knife  12  and can be used to define a cutting depth associated with operation of knife  12 . A contact face  28  of pressure foot  24  is maintained in contact with the material being cut during the cutting operation to maintain the position of the material relative to the knife. Due to the translational association of contact face  24  to the material, contact face  28  is coated with a low friction material, such as polytetrafluoroethylene, so that pressure foot  24  can slide across the surface of the material being cut while applying a downward pressure thereto. 
         [0006]    Unfortunately, such cutting tools have proven inadequate for efficiently and repeatably generating quality cut parts from composite materials. As pressure foot  24  slides across the material being cut, particulates of cut material and or backing materials collect on contact face  28  of pressure foot  24 . This collection of microscopic debris propagates in the form of a resin-like material that adversely affects the desired low friction interaction between the contact face  28  and the material being cut. The increased friction associated with the resin-like material requires that the cutting table machine operate at higher loads to continue to perform similar cutting operations. Furthermore, the increased friction between pressure foot  24  and the cutting material detracts from cut quality and/or requires that parts be produced with greater than desired cut tolerances. 
         [0007]    A cutting tool assembly  40  associated with another category of cutting tools is shown in  FIGS. 8 and 9 . This category of cutting tool assemblies  40  includes a rotatable blade or cutting wheel  42  that has a 360 degree cutting edge  44 . A mount body  46  receives a bearing  48  and supports cutting wheel  42  in a cantilevered fashion. A pair of plates  50  laterally support cutting wheel  42 . A fastener  52 , a sleeve  54 , and a nut  56  secure cutting wheel  42  to mount body  46  so that cutting wheel  42  is free to rotate relative to the mount body  46  as it is translates over a material  58  being cut. A bottom surface  60  of mount body  46  can be maintain in an offset relation relative to material  58  if the material is otherwise positionally attached to the cutting table. Alternatively, surface  60  may be coated with a low friction material, such as polytetrafluoroethylene, so that the bottom surface  60  of mount body  46  can apply a downward holding pressure to material  58  without adversely translating material  58  during a cutting operation. Although such wheel-type cutting tool assemblies have proven beneficial for cutting generally light weight materials such as fabric, cloths, and or leather materials, such tools have proven inadequate for use with many harder to cut materials such as composite materials. 
         [0008]    Accordingly, there is a need for a cutting table cutting tool assembly that can maintain the position of a generally rigid material relative to a cutting edge, is capable of extended cutting use, and does not unduly interfere with efficient operation of the cutting table system. 
       SUMMARY OF THE INVENTION 
       [0009]    The present invention provides a cutting table cutting tool assembly that addresses one or more of the problems discussed above. According to one aspect of the invention, a cutting table cutting tool assembly is disclosed that includes a holder that supports a blade. At least one roller is attached to the holder and extends beyond a perimeter of the holder in a direction that is normal to an axis of rotation of the roller. The blade extends from the holder in the same direction as the roller and includes a cutting edge that is oriented in a plane that is generally normal to the axis of rotation of the roller. During a cutting process, the roller maintains the position of the material with respect to the cutting edge of the blade thereby improving the performance of the cutting process. 
         [0010]    Another aspect of invention useable with one or more of the above aspects discloses a cutting table cutting tool assembly that includes a body having a first end for being secured to a mandrel of a cutting table system and a second end that is opposite the first end. A guide is attached to the second end of the body and has a material facing surface that is directed away from the second end of the body. A blade is attached to the body such that it extends beyond the material facing surface of the guide. At least one roller is attached to the guide and extends beyond the material facing surface of the guide in a direction aligned with blade. The roller maintains a desired tension on the material be cut so that the blade can pass therethrough without translating the material. 
         [0011]    Another aspect of the invention usable with one or more of the above aspects discloses a cutting tool assembly for use with cutting table systems. The cutting tool assembly includes a holder that is constructed to engage a cutting table system. A shoe having an opening is attached to the holder. A knife is attached to the holder and extends through the opening and beyond an edge of the shoe. A cutting edge is formed along a portion of the knife that extends beyond the shoe. A first roller and a second roller are attached to the shoe and generally flank the knife. Each roller has an outer race that extends beyond the shoe proximate the cutting edge and secures the material being cut as the knife performs a cutting operation. 
         [0012]    A further aspect of the invention that is combinable with one or more of the above aspects discloses a method of forming a cutting table system cutter assembly. A mount body is formed to cooperate with a cutting table system and a knife blade is attached to the mount body. A shoe is attached to the mount body so that a tip of the knife blade extends beyond a bottom surface of the shoe. At least one roller is attached to the shoe so that a surface of the roller that contacts a material to be cut is located between the tip of the knife blade and the bottom surface of the shoe in a direction generally perpendicular relative to a cutting direction. 
         [0013]    Preferably, another aspect of the invention that is combinable with one or more of the above aspects includes providing a pair of rollers that generally flank the blade of knife of the cutting tool assembly. Preferably, both rollers extend a common distance beyond the guide or shoe so that an outer edge of the rollers is positioned between a tip of the blade and a bottom surface of the shoe. More preferably, the pair of rollers rotate about a common axis. 
         [0014]    Another aspect of the invention combinable with one or more of the above aspects includes forming a cutting edge on a portion of the knife or blade and orienting the cutting edge so that it is canted or tilted relative to a plane of the cutting material. Preferably, the cutting edge is oriented in a plane that is perpendicular to an axis of rotation of the rollers. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    The drawings illustrate one preferred embodiment presently contemplated for carrying out the invention. In the drawings: 
           [0016]      FIG. 1  is perspective view of a cutting table system equipped having a movable mandrel equipped with a cutting tool assembly according to the present invention; 
           [0017]      FIG. 2  is a perspective view of the mandrel and cutting tool assembly shown in  FIG. 1 ; 
           [0018]      FIG. 3  is a perspective view of the cutting table cutting tool assembly shown in  FIG. 1 ; 
           [0019]      FIG. 4  is an exploded perspective view of the cutting tool assembly shown in  FIG. 3 ; 
           [0020]      FIG. 5  is a perspective view of another side of a shoe portion of the cutting tool assembly shown in  FIG. 4 ; 
           [0021]      FIG. 6  is a front side elevation view of the cutting tool assembly shown in  FIG. 3  with a roller and a portion of the shoe shown in cross section; 
           [0022]      FIG. 7  shows one prior art cutting table cutting tool assembly; and 
           [0023]      FIGS. 8 and 9  shows another prior art cutting table cutting tool assembly. 
       
    
    
       [0024]    In describing the preferred embodiments of the invention that are illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, it is not intended that the invention be limited to the specific terms so selected and it is to be understood that each specific term includes all technical equivalents that operate in a similar manner to accomplish a similar purpose. For example, the word “connected,” “attached,” or terms similar thereto are often used. They are not limited to direct connection but include connection through other elements where such connection is recognized as being equivalent by those skilled in the art. 
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0025]      FIG. 1  shows a cutting table system  100  that is equipped with a cutting tool assembly  102  according to the present invention. Cutting table system  100  includes a cutting bed or table  104  that is configured to support a material  106  that is to be cut. A computer  108  controls movement of a horizontal arm  110  and a vertical arm  112  that travel over table  104 . A cutting head or mandrel  114  is supported by arms  110 ,  112  in a manner such that mandrel  114  can be moved across cutting table  104 . That is, translation of arms  110 ,  112  relative to table  104  translates mandrel  114  and cutting tool assembly  102  relative to material  106 . As described further below with respect to  FIG. 2 , mandrel  114  also enables up and down movement of cutting tool assembly  102  relative to material  106 . 
         [0026]      FIG. 2  shows mandrel  114  removed from cutting table system  100 . An optional position system  116  includes a sensor  118  that is configured to monitor and communicate a position of mandrel  114  to computer  108  of cutting table system  100 . It is understood that sensor  118  can be any of a photo sensor, a laser sensor, and/or other physical proximately sensors such as variable output limit switches that physically contact cutting material  106 . It is further appreciated that some cutting table systems are equipped with computer control systems that are so sophisticated and/or can be configured to produce parts with acceptable tolerances that the providing such a position verification system proves redundant and/or unnecessary. 
         [0027]    Mandrel  114  includes an actuator  120  having a movable shaft  122 . Shaft  122  translates in an up and down direction, indicated by arrow  124 . Cutting tool assembly  102  is attached to shaft  122  such that cutting tool assembly  102  also moves in up and down direction  124  with shaft  122 . Such an association allows the cutting edge of cutting tool assembly  102  to be translated relative to material  106  in a cutting and a non-cutting orientation. That is, when oriented in a cutting position, a knife or a blade  126  of cutting tool assembly  102  engages material  106  such that translation of mandrel  114  via manipulation of arms  110 ,  112  results in blade  126  cutting material  106 . When oriented in a non-cutting or raised position, blade  126  is maintained at an offset distance above material  106  such that translation of mandrel  114  by movement of arms  110 ,  112  translates blade  126  relative to material  106  in a manner that does not cut the material. Such operation allows for efficient cutting of desired shapes and cutting of multiple parts with efficient utilization of material  106  without repositioning of material  106  relative to table  104 . 
         [0028]    Those skilled in the art will appreciate that cutting table system  100  is merely exemplary of one of many types of cutting table systems useable with the present invention. Understandably, cutting table system  100  is exemplary of one automated cutting system whose operation can be improved with use of cutting tool assembly  102 . It is appreciated that other cutting table systems configured in other manners of translating the material relative to the cutting tool assembly are envisioned and within the scope of appending claims. That is, it is appreciated that other cutting table systems exist wherein a cutting table can be translated relative to a more stationary cutting tool, systems wherein the material can be translated relative to a cutting tool, systems wherein a cutting tool is manipulated by a multi-jointed unitary arm, and/or various combinations of such cutting table features. 
         [0029]      FIG. 3  shows cutter assembly or cutting tool assembly  102  removed from cutting table system  100 . Cutting tool assembly  102  includes a body, a mount body, a tool or blade holder, or holder  140  that has a first portion or end  142  and a second or lower portion or end  144 . First end  142  of holder  140  is configured to cooperate with mandrel  114  of cutting table system  100 . Second end  144  of holder  140  cooperates with a foot, guide, or shoe  146 . A knife or blade  148  is secured to holder  140  and is positioned so that an exposed portion  151  of blade  148  passes through a slot or opening  152  formed in shoe  146 . 
         [0030]    A cutting edge  156  that is formed along a portion of blade  148 . Cutting edge  156  is generally inclined with respect to a material facing surface  158  of shoe  146 . Preferably, a distal end  160  of blade  148  is offset from material facing surface  158  of shoe  146  a distance that is sufficient to allow distal end  160  to pass entirely through material  106  without shoe  146  coming into contact with material facing surface  158  of shoe  146 . 
         [0031]    As shown in  FIGS. 3 and 4 , a first pressure wheel or roller  170  and a second pressure wheel or roller  172  are positioned on generally opposite lateral sides  174 ,  176  of shoe  146 . It is appreciated that cutting tool assembly  102  may be equipped with only one roller for those applications wherein one roller is sufficient to maintain a desired orientation of material  106  relative to blade  148 . 
         [0032]    Rollers  170 ,  172  each include an inner race  180  and an outer race  182  that are separated by a number of roller elements or bearings  184 . Inner race  180  of each roller  170 ,  172  is supported by a post or a hub  186  that is attached to shoe  146 . A rib or lip  188  is formed proximate an end  190  of each hub  186 . 
         [0033]    A first portion  192  of each hub  186  is constructed to pass through an opening  198  formed in each inner race  180  of each roller  170 ,  172 . Each lip  188  has a diameter that is larger than a diameter of a respective first portion  192  of each hub  186 . First portion  192  of each hub  186  passes through the opening  198  of a respective hub  186 . A vertical portion  200  of each lip  188  cooperates with a side surface  202  of each inner race  180  of a respective roller  170 ,  172  so as to generally fix the position of rollers  170 ,  172  relative to shoe  146  in a direction generally aligned with an axis of rotation  210  of rollers  170 ,  172 . Preferably, rollers  170 ,  172  are similarly sized so that each outer races  182  rotates about axis  210 . It is appreciated that rollers  170 ,  172  could have dissimilar sizes and would therefore have separate axis of rotation. 
         [0034]    An opening  212  is formed in each hub  186  and includes a chamfered or tapered section or portion  214  that is formed proximate each lip  188 . A fastener  216  having a threaded portion  218  and a head portion  220  secures each of hubs  186  to shoe  146 . Preferably, each head portion includes a chamfered or tapers section  224  that cooperates with the tapered portion  214  of the respective hub  186 . Such a construction ensures that each hub  186  is centered relative to axis  210 . 
         [0035]    Threaded portion  218  of each fastener  216  threadingly cooperates with an opening  226  formed in the respective opposite lateral side  174 ,  176  of shoe  146 . Fasteners  216  cooperate with shoe  146  in a manner so that fasteners  216  do not interfere with or otherwise alter the position of blade  148  relative to holder  140 . Alternatively, rather than securing hubs  186  to shoe  146  with fasteners  216 , each hub  186  could be formed integrally with shoe  146  or be configured to directly engage a corresponding opening formed in shoe  146  thereby omitting the use of fasteners  216 . 
         [0036]    It is appreciated that, regardless of the specific construction of hubs  186 , rollers  170 ,  172  could be engaged/disengaged from respective hubs  186  via translation of the respective hub/roller in a lateral outward direction generally aligned with axis  210 . It is further appreciated that hub  186  need not be provided with lip  188  provided fasteners  216  secure a locking ring and/or plate washer to the respective hub  186  outboard of the respective hub so as to maintain the lateral position of rollers  170 ,  172  relative to shoe  146 . 
         [0037]    Referring to  FIGS. 4 and 5 , shoe  146  includes a cavity  230  that is formed in an upward facing side  232  of shoe  146 . Upward facing side  232  of shoe  146  is defined as being generally opposite the material facing surface  150  of shoe  146 . Cavity  230  is generally shaped to accommodate lower portion  144  of holder  140  being positioned in the cavity  230 . The lower portion  144  of holder  140  includes a recess  236  that is constructed to accommodate blade  148  and a backer or support block or support  240 . Support  240  ensures blade  148  is securely supported by holder  140 . Blade  148  and support  240  are received in recess  236  so as to be generally positioned within a footprint of cavity  230 . Such an orientation allows shoe  146  to translate in a direction that is generally aligned with a longitudinal axis of holder  140 . 
         [0038]    A fastener  244  passes through an opening  246  formed in support block  240  and an opening  248  formed in blade  148 . A threaded portion  250  a fastener  244  threadingly engage an opening  252  formed in second portion  144  of holder  140  and secures blade  148  and support block  240  to holder  140 . As shown in  FIG. 4 , shoe  146  includes a forward facing opening  256  that cooperates with a fastener, such as a set screw  258 . Set screw  258  cooperates with opening  256  and slidably engages an index or a groove or channel  260  formed in holder  140 . Channel  260  is generally aligned with a longitudinal axis  262  of holder  140  and is generally aligned with a longitudinal axis of blade  148 . Set screw  258  and channel  260  allow a user to select a desired distance that blade  148  protrudes beyond shoe  146 . 
         [0039]    Cutting edge  156  of blade  148  is oriented in a crossing direction relative to longitudinal axis  262  of holder  140 . Said in another way, cutting edge  156  is oriented in a crossing direction relative to a plane of material  106 . Axis  262  and channel  260  are oriented to be generally perpendicular to the plane of material  106 . Such an orientation ensures an efficient cutting operation as cutting edge  156  moves through material  106  in both a piercing direction that is generally perpendicular to the plane of the material and a cutting direction within the plane of material  106 . 
         [0040]    As shown in  FIGS. 4 and 6 , a fastener, such as a set screw  264 , cooperates with an opening  266  formed in holder  140  and secures cutting tool assembly  102  to mandrel  114 . Referring to  FIG. 6 , when oriented in a cutting position, rollers  170 ,  172  engage material  106  so as to generally flank the cutting edge  156  of blade  148 . As cutting tool assembly  102  translates relative to material  106 , outer races  182  rotate such that a contact area  270  forms between each roller  170 ,  172  and material  106 . As cutting tool assembly  102  moves, each outer race  182  rotates relative to material  106 . Such a configuration maintains a desired holding pressure for the cutting operation while reducing the drag inference between cutting tool assembly  102  and material  106 . 
         [0041]    Accordingly, cutting tool assembly  102  reduces the counter-productive frictional forces generated by the sliding of a pressure foot across the cutting material associated with the prior art cutting table cutting tool assemblies. Accordingly, cutting table cutting tool assembly  102  improves cutting speed, improves cutting precision, attains improved cutting blade operating life, requires less cutting table generated down or holding pressures, and achieves an overall improvement in cutting table performance and operation. 
         [0042]    Therefore, one embodiment of the invention includes a cutting table cutting tool assembly that includes a body having a first end that is securable to a mandrel of a cutting table system and a second end opposite the first end. A guide is attached to the second end of the body and has a material facing surface that is directed away from the second end of the body. A blade is attached to the body such that it extends beyond the material facing surface of the guide. At least one roller is attached to the guide and extends beyond the material facing surface of the guide in a direction aligned with blade. 
         [0043]    Another embodiment of the invention that includes or is combinable with one or more of the features or aspects of the embodiment above includes a cutting tool assembly that includes a holder constructed to engage a cutting table system. A shoe is attached to the holder and has an opening formed therethrough. A knife is attached to the holder and extends beyond the opening formed in the shoe. A cutting edge is formed along a portion of the knife that extends beyond the shoe. A first roller and a second roller are attached to the shoe and generally flank the knife. Each roller has an outer race that extends beyond the shoe proximate the cutting edge. 
         [0044]    Another embodiment of the invention that includes or is combinable with one or more of the features or aspects of the embodiments above includes a method of forming a cutting table system cutter assembly. A mount body is formed to cooperate with a cutting table system and a knife blade is attached to the mount body. A shoe is attached to the mount body so that a tip of the knife blade extends beyond a bottom surface of the shoe. At least one roller is attached to the shoe so that a surface of the roller that contacts a material to be cut is located between the tip of the knife blade and the bottom surface of the shoe in a direction generally perpendicular relative to a cutting direction. 
         [0045]    The present invention has been described above in terms of the preferred embodiment. It is recognized that various alternatives and modifications may be made to these embodiments which are within the scope of the appending claims.