Abstract:
A guard for use on a cutting knife of a slitting machine has a body with an opening sized to permit a cutting wheel mounted in the cutting knife to extend through the opening. The body has two ends, with an attachment member associated with each end. The attachment members are shaped to engage receiving members on the cutting knife, so that the guard may be removably attached to the cutting knife. The guard acts as a blade guard, covering the cutting wheel fully when the cutting wheel is retracted, such as during machine set-ups. The opening allows the cutting wheel to be actuated into position during machine operation.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates generally to slitter guards, and more particularly to slitter guards used on slitting machines. 
       BACKGROUND 
       [0002]    In manufacturing, machines can pose a safety hazard to the individuals in and around those machines. This is especially true of machines used to cut or slice materials. To maximize safety, a wide variety of guards, covers, and fencing are used to protect the individual from the sharp cutting surfaces while the machine is operating. The sharp cutting surface may also be dangerous even when the machine is not operating. For example, a person may need to place his or her hands, arms, and perhaps his or her whole body in the area of the cutting surfaces in order to service or adjust the machine. 
         [0003]    Machines used to convert large rolls of material, such as paper or plastic film, into smaller rolls or other products being made from the materials, typically use a plurality of sharp cutting surfaces. Converting the large rolls into smaller or narrower rolls is done by cutting or slitting. More specifically, a slitting machine unwinds a large roll of material or film and passes it through one or more cutting knives. The cutting knives are spaced apart along the width of the material to convert the wide strip into a plurality of narrower strips, which are typically wound back into separate narrower rolls. Examples of products made this way include masking tape, saran wrap, bandages, and several forms of labels. Depending on the width of the strips being produced, the cutting knives may be moved relative to each other during “machine set-up”. 
         [0004]      FIG. 1  shows a typical prior art cutting knife  900  with a cutting wheel  902  shown in a retracted position  904 . The cutting wheel  902  is also shown in an actuated or extended position  906  by phantom lines. The cutting knife  900  has a housing  908 , which covers most of the retracted cutting wheel  902 . In the actuated or extended position  906 , a relatively large amount of cutting wheel  902  extends out of the housing  908  in close proximity to a roller  910 . In this position the cutting wheel  902  can cut the work material (not shown) such as paper traveling between the roller  910  and the cutting knife  900 . 
         [0005]    When a person services or adjusts the cutting knife  900 , the roller  910 , or the work material  912  (not shown), the person&#39;s hands and arms may inadvertently contact the large exposed portion  914  or the small exposed portion  916  of the cutting wheel  902 . That inadvertent contact may seriously injure the person&#39;s hands or arms. 
         [0006]    To provide some measure of safety, the industry uses actuated cutting knives such that when not in use, less of the cutting wheel is exposed. Still, some of the sharp cutting wheel remains exposed as illustrated in  FIG. 1 . 
         [0007]    A need, therefore, exists for a guard for these cutting knives that would completely cover the sharp cutting wheel while the cutting wheel is in the retracted position. This guard should preferably be able to remain installed, and not interfere with the cutting wheel when actuated to its extended position. The summary and detailed description that follow will further explain a device that meets this need. 
       SUMMARY 
       [0008]    In one embodiment, a slitter guard for use on a cutting knife of a slitting machine has a body with an opening sized to permit a cutting wheel mounted in the cutting knife to extend through the opening. The body has first and second ends. There is an attachment member operatively associated with the first end and a second attachment member operatively associated with the second end. The attachment members are shaped to engage a first and second receiving member on the cutting knife, so that the slitter guard is removably attached to the cutting knife when the first and second attachment members engage the respective first and second receiving members on the cutting knife. 
         [0009]    Another embodiment described is a method for attaching a slitter guard to a cutting knife. The slitter guard has a body with an opening and first and second attachment members. The method includes contacting the first attachment member of the slitter guard to a first receiving member on the cutting knife, pivoting the body of the slitter guard about the first receiving member, and engaging the second attachment member of the slitter guard onto a second receiving member on the cutting knife. 
         [0010]    These and other features, objects, and advantages of the invention will become more readily apparent to those skilled in the art in view of the following detailed description, taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with a general description of the invention given above, and the detailed description given below, serve to explain the principles of the invention. 
           [0012]      FIG. 1  is an elevational view of a prior art cutting knife positioned over a roller of a cutting machine. 
           [0013]      FIG. 2  is a perspective view of two cutting knives positioned in a slitting machine over work material. 
           [0014]      FIG. 3A  is an elevational view of a cutting knife partially in cross-section showing the cutting wheel, and the slitter guard fully in cross-section, partially installed. 
           [0015]      FIG. 3B  is an elevational view similar to  FIG. 3A  of a cutting knife in a cutting machine with the slitter guard installed. 
           [0016]      FIG. 4  is a perspective view of the slitter guard. 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    With reference to  FIG. 2 , a slitting machine  10  is shown with a web of work material  12  such as paper traveling in the machine direction indicated by arrow  14  labeled MD. The work material  12  travels over a roller  16 . The outer roller surface  18  of roller  16  may be solid, grooved, or of any configuration suitable for the work material  12  being cut. The slitting machine  10  also includes a locating bar  20  which has a male dovetail portion  22  that is configured to receive the female dovetail portion  24  of cutting knives  26 . The cutting knives  26  are held tightly by fasteners  28  in threaded holes  30  which push on a locking wedge  32  that is on top of the male dovetail portion  22 . Each cutting knife  26  is independently movable along the locating bar  20  to create a space  34  between the cutting knives  26 . 
         [0018]    The cutting knife  26  has a housing  36  comprised of a left sidewall  38 , a right sidewall  40 , a forward end  42  and an aft end  44  when looking in the machine direction. The two sidewalls  38 ,  40  are spaced apart to allow a cutting wheel  46  to rotate within the housing  36 . The left sidewall  38  and the right sidewall  40  are spaced apart by a first bushing  48  and by a second bushing  50  ( FIG. 3B ). A power source  56  such as compressed air travels through a tube  58  to actuate the cutting wheel  46  from its retracted position  70  ( FIG. 3A ) to its cutting position  62 . 
         [0019]    One embodiment of a slitter guard  64  is installed on the cutting knives  26 . The slitter guard  64  covers most of the cutting wheel  46  even in its extended position. With the slitter guard  64  in place, only a small cutting edge  66  of the cutting wheel  46  is exposed to contact the work material  12 . If the slitter guard  64  were not present, a much larger portion of the cutting wheel  46  would be visible as described with respect to  FIG. 1 . 
         [0020]    With reference to  FIG. 3A , the slitter guard  64  has an aft guard end  71 , a body  72 , and a forward guard end  73 . On the aft guard end  71  is a first attachment member  74 , which includes a first overhang  76 , and a first arcuate portion  78 . On the forward guard end  73  is a second attachment member  80  that includes a second overhang  82  with an angled edge  84 , a second arcuate portion  86 , and a flexing neck  88 . A profile portion  90  starts forward of the first arcuate portion  78  and continues to the second arcuate portion  86 . The profile portion  90  is shaped to closely match the lower edges  91  of the sidewalls  38 ,  40  ( FIG. 3B ) of the housing  36 . 
         [0021]    To install the slitter guard  64 , the first attachment member  74  initially engages the first bushing  48  of the cutting knife  26 . The slitter guard  64  is then pivoted around the first bushing  48 , as indicated by the arrow  96  until the second attachment member  80  engages the second bushing  50 . The second attachment member  80  is in an un-flexed condition prior to engaging the second busing  50 . As the slitter guard  64  pivots, the angled edge  84  contacts the second bushing  50  causing the second attachment member  80  to flex at the flexing neck  88 , allowing the second overhang  82  to resiliently move around the second bushing  50 . When the slitter guard  64  is fully engaged, the flexing neck  88  returns to a substantially un-flexed position ( FIG. 3B ). 
         [0022]      FIG. 3B  shows the slitter guard  64  fully installed and in the substantially un-flexed condition with the cutting wheel  46  in the cutting position  62  exposing the small cutting edge  66 . The slitter guard  64  is pivoted around the first bushing  48  and the second attachment member  80  fits onto the second bushing  50 . The second overhang  82  retains the slitter guard  64  on the second bushing  50 . With slitter guard  64  in place, none of the cutting wheel  46  is exposed when it is in its retracted position  70 . Thus, the slitter guard  64  provides a safe environment for a person who needs to place his or her hands or arms in the area of the cutting knife  26  when the cutting wheel  46  is in the retracted position  70 . 
         [0023]    Slitter guard  64  also includes a finger grab  102  to use when removing the slitter guard  64  from the cutting knife  26 , such as would be necessary when the cutting wheel  46  must be replaced. To remove the slitter guard  64 , a finger or thumb pushes down and away on finger grab  102  causing the flexing neck  88  to flex and the second overhang  82  to move away from the second bushing  50 , so that the slitter guard  64  can be removed from the cutting knife  26 . 
         [0024]    Although bushings  48  and  50  are shown, any alternative spacer or bushing would work as long as the shape of it and the shape of the first and second attachment members are configured to work together to form a removable connection. In most cases, the cutting knives  26  will have round bushings or other pre-existing spacers for which a slitter guard  64  can be created to match. As an alternative, it may be possible to swap out spacers of one configuration for those created to match a specific attachment member. 
         [0025]    With reference to  FIG. 4 , the slitter guard  64  includes an opening or slot  104  through which the cutting wheel  46  travels when it is extended. The top of the slot  104  has a beveled edge  106  on the two long edges. In other embodiments, the top of the slot  104  may not include the beveled edges  106 . While the arcuate portions  78 ,  86  are shown as solid surface, they may be constructed with a mesh pattern, such as honeycomb, to vary the weight and stiffness properties of the attachment members  74 ,  80 . 
         [0026]    As illustrated and described, the slitter guard  64  is a single integral piece which can be made of any suitable structural material such as plastic, metal, wood, rubber, etc. The slitter guard  64  may also be constructed from multiple pieces instead of a single integral piece. For example, the attachment members  74 ,  80  could be separate pieces that are affixed to the main body of the slitter guard  64  when it is being assembled. 
         [0027]    In addition, the design of the attachment members could be redesigned to permit other ways of removably attaching the slitter guard  64  to the cutting knife  26 . For example, screws, hooks, clamps, adhesives, magnets, straps, etc., could be used instead of the attachment members  74 ,  80 . 
         [0028]    As illustrated in  FIGS. 2 and 3B , the profile  90  of the slitter guard  64  closely matches the profile of the cutting knife  26 . The profile  90  of the, slitter guard  64  however, need not precisely match that of the cutting knife  26  in order to still provide protection from the cutting wheel  46 . If gaps are present between profile portion  90  and lower edges  91 , it would still be difficult for a person to inadvertently contact a sharp edge as long as those gaps were kept small or positioned in non-dangerous locations, such as near the center of the cutting wheel  46  rather than at the edges of the cutting wheel  46 . 
         [0029]    While the present invention has been illustrated by the description of one or more embodiments thereof, and while the embodiments have been described in considerable detail, they are not intended to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and method and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the general inventive concept.