Abstract:
The present disclosure relates to safety blades for use in utility knives, related assemblies and methods of manufacturing. More specifically, the present disclosure relates to safety blades for use in utility knives, related assemblies and methods of manufacture which limit user exposure to associated cutting edges.

Description:
RELATED APPLICATIONS 
       [0001]    This application is a continuation-in-part of U.S. patent application Ser. No. 12/620,999, which was filed on Nov. 18, 2009. The entire disclosure of which is incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present disclosure relates to safety blades for use in utility knives, related assemblies and methods of manufacturing. More specifically, the present disclosure relates to safety blades for use in utility knives, related assemblies and methods of manufacture which limit user exposure to associated cutting edges. 
       BACKGROUND 
       [0003]    Utility knives are used for a host of purposes, such as opening cardboard boxes, cutting sheet material, cutting web material, opening packages, etc. Injuries to the users of utility knifes are all too common due to inadvertent contact with the cutting edges of the associated blades. Injuries may be particularly severe when the given utility knife includes a razor blade. 
         [0004]    Inadvertent contact with the cutting edges of blades can be equally common during blade removal, insertion and handling. Inadvertent contact with the cutting edges is particularly problematic when a user is removing or inserting a double edge razor blade into an associated utility knife. 
         [0005]    Blades for use in utility knives and utility knives which limit user exposure to the associated cutting edges are desirable. Methods of manufacturing related blades and utility knives are also desirable. 
       SUMMARY 
       [0006]    A safety blade for use within a utility knife includes a blade body, a blade attachment, a first blade shield and a second blade shield, wherein the blade body, the blade attachment, the first blade shield and the second blade shield compose a contiguous piece of metal. The blade attachment comprises a first inner surface and a second inner surface juxtapose on opposing edges of the blade attachment, where a thickness of the first inner surface is greater than a thickness of the first blade cutting edge and less than or substantially equal to a thickness of the blade body and a thickness of the second inner surface is greater than a thickness of the second blade cutting edge and less than or substantially equal to the thickness of the blade body. The first blade shield and the first inner surface of the blade attachment form a first blade throat which limits exposure to a first blade cutting edge, wherein the first blade shield comprises a first blunt tip having a first inner edge with a thickness that is greater than a thickness of the first blade cutting edge and less than or substantially equal to the thickness of the blade body and wherein the first inner surface of the blade attachment and the first inner edge of the first blunt tip extend beyond the first blade cutting edge. The second blade shield and the second inner surface of the blade attachment form a second blade throat which limits exposure to a second blade cutting edge, wherein the second blade shield comprises a second blunt tip having a thickness that is greater than a thickness of the second blade cutting edge and less than or substantially equal to the thickness of the blade body and wherein the second inner surface of the blade attachment and the second inner edge of the second blunt tip extend beyond the second blade cutting edge. 
         [0007]    In another embodiment, a method of manufacturing a safety blade for use within a safety utility knife assembly includes providing a strip of blade material and forming a rough blade shape from the strip of blade material, wherein the rough blade shape comprises a blade body, a blade attachment with an inner surface and a blade shield. The method also includes forming a blade cutting edge in the rough blade shape, wherein the blade shield and the inner surface of the blade attachment form a blade throat which limits exposure to the blade cutting edge and wherein the blade shield comprises a blunt tip having an inner edge with a thickness that is greater than a thickness of the blade cutting edge and less than or substantially equal to a thickness of the blade body and wherein the inner surface of the blade attachment extends beyond a heal of the blade cutting edge and the inner edge of the blunt tip extends beyond a toe of the blade cutting edge. 
         [0008]    In a further embodiment, a safety utility knife assembly includes a blade having a predetermined thickness and a cutting edge. The safety utility knife further includes a blade holder, wherein an operative end of the blade holder is offset from a blade holder section of the blade holder by a distance substantially equal to the predetermined thickness of the blade and wherein the operative end of the blade holder includes a blade throat that limits exposure to the cutting edge of the blade. 
         [0009]    The features and advantages described in this summary and the following detailed description are not all-inclusive. Many additional features and advantages will be apparent to one of ordinary skill in the art in view of the drawings, specification, and claims hereof. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0010]      FIGS. 1   a  and  1   b  depict an example safety utility blade for use within a utility knife assembly; 
           [0011]      FIG. 2  depicts the safety utility blade of  FIGS. 1   a  and  1   b  in proximity to a human finger; 
           [0012]      FIG. 3A  depicts an example progression of manufacturing the safety utility blade of  FIGS. 1   a ,  1   b  and  2 ; 
           [0013]      FIG. 3B  depicts an example blade edge grinding and honing drum apparatus; 
           [0014]      FIG. 3C  depicts an example blade edge grinding and honing wheel; 
           [0015]      FIG. 3D  depicts an example flow diagram for a method of manufacturing the safety utility blade of  FIG. 3A ; 
           [0016]      FIG. 3E  depicts an example flow diagram for a method of manufacturing the safety utility blade of  FIGS. 4A-4D ; 
           [0017]      FIGS. 4A-4D  depict a second example progression of manufacturing the safety utility blade of  FIGS. 1A ,  1 B and  2 ; 
           [0018]      FIGS. 5A and 5B  depict examples of safety cutter heads which include a safety utility blade of  FIGS. 1   a ,  1   b ,  2 ,  3 A and  4 A- 4 D; 
           [0019]      FIG. 6  depicts the safety cutter head of  FIG. 5B  proximate an associated safety utility knife handle; 
           [0020]      FIG. 7  depicts the safety cutter head of  FIG. 5B  engaged with an associated safety utility knife handle to form a safety utility knife assembly; 
           [0021]      FIGS. 8A-8H  and  8 J- 8 K depict an example safety utility knife assembly; 
           [0022]      FIGS. 9A-9H  and  9 J depict an example blade carriage for use within the safety utility knife assembly of  FIGS. 9A-9H  and  9 J; 
           [0023]      FIG. 10A  depicts an example progression of manufacturing a blade for use in the safety utility knife assembly of  FIGS. 9A-9H  and  9 J; 
           [0024]      FIGS. 10B-10D  depict a second example progression of manufacturing a blade for use in the safety utility knife assembly of  FIGS. 9A-9H  and  9 J; 
           [0025]      FIG. 10E  depicts an example flow diagram for a method of manufacturing the safety blade of  FIG. 10A ; 
           [0026]      FIG. 10F  depicts an example flow diagram for a method of manufacturing the safety blade of  FIGS. 10B-10D ; and 
           [0027]      FIG. 11  depicts an example safety utility blade for use in a safety utility knife assembly as in  FIGS. 9A-9H  and  9 J. 
       
    
    
     DETAILED DESCRIPTION 
       [0028]    The safety utility blades and safety utility knife assemblies of the present disclosure incorporate various features that limit user exposure to associated cutting edges. The manufacturing methods of the present disclosure may be used to produce the disclosed safety utility blades and safety utility knife assemblies. 
         [0029]    With initial reference to  FIGS. 1A and 1B , a safety utility blade  100  may have a body  105  formed from a relatively thin and substantially flat material  107 , such as ceramic, heat treated carbon steel, ceramic coated steel, stainless steel, Teflon coated material, etc. For example, the material  107  may be approximately 0.025 inches thick  106   b . A blade blank (e.g. blade blank  300   a ,  400   a ,  1000   a ,  1000   b  of  FIGS. 3A ,  4 A,  10 A and  10 B, respectively) may be 1.0964567 inches from a first end  132  to a second end  142  and 0.3917323 inches from a top side  108  to a bottom side  109 . The safety utility blade may include blade securing holes  115 ,  120 ,  125  which may be approximately 0.0984252 inches in diameter. As described herein the blade securing holes  115 ,  120 ,  125  may, at least in part, secure a safety utility blade  100  to a safety utility knife cutting head (e.g., safety utility knife cutting head  500   a  of  FIG. 5A  or  500   b  of  FIG. 5B ). The safety utility blade  100  may be formed from a suitable material  107  for retaining a sharpened edge  136 ,  137 , and, when that material  107  is metal, the body  105  preferably has a thickness  106   b  of at least 0.0156 inches and preferably not greater than about 0.0313 inches. What might be characterized as a “heavy-duty” safety utility blade  100  is approximately 0.025 inches thick, and the thickness  106   b  for what might be characterized as a “regular duty” safety utility blade  100  is approximately 0.017 inches. The sharpened portion  135 ,  145  is approximately 0.0492 inches high. A center of the first blade securing hole  115  may be approximately 0.23622 inches from the bottom side  109  and approximately 0.54825 inches from the first end  132 . A center of the second blade securing hole  120  may be approximately 0.07874 inches from the bottom side  109  and approximately 0.449825 inches from the first end  132 . A center of the third blade securing hole  125  may be approximately 0.07874 inches from the bottom side  109  and approximately 0.449825 inches from the second end  142 . The sharpened portion  135 ,  145  may be coated with a material, such as paint, that may wear away as the associated safety utility blade  100  is being used to indicate whether the safety utility blade  100  has been used. The consistency of the material, such as paint, may be selected such that the amount of wear of the material is indicative of the amount of use of and/or the sharpness of the safety utility blade  100 . 
         [0030]    With further reference to  FIGS. 1A and 1B , the safety utility blade  100  may include a body portion  105 ,  105   b  and a blade attachment portion  110 ,  110   b . The first sharpened portion  135  of the safety utility blade  100  may include a first shoulder  137 , a first cutting edge  136 , a first heal  139  and a first toe  138 . The blade attachment portion  110 ,  110   b  may include a first edge  111  extending from the first heal  139  to the bottom side  109 . The safety utility blade  100  may further include a first blade shield  130  having a first blunt tip  131  having a radius approximately 0.03937 inches and a thickness that is greater than the first sharpened portion  135  and less than or equal to the thickness  106   b  of the body  105 . The first blade shield  130  may include a first inner edge  133  that extends from the first toe  139  to the first blunt tip  131  and may have a thickness that is greater than the first sharpened portion  135  and less than or equal to the thickness  106   b  of the body  105 ,  105   b . A first distance  126   b  between the first shoulder  137  and the first cutting edge  136  may be approximately 0.04921 inches. 
         [0031]    With further reference to  FIGS. 1A and 1B , the safety utility blade  100  may include a second sharpened portion  145  which may include a second shoulder  147 , a second cutting edge  146 , a second heal  149  and a second toe  148 . The blade attachment portion  110 ,  110   b  may include a second edge  112  extending from the second heal  149  to the bottom side  109 . The safety utility blade  100  may further include a second blade shield  140  having a second blunt tip  141  having a radius approximately 0.03937 inches and a thickness that is greater than the second sharpened portion  145  and less than or equal to the thickness  106   b  of the body  105 . The second blade shield  140  may include a second inner edge  143  that extends from the second toe  149  to the second blunt tip  141  and may have a thickness that is greater than the second sharpened portion  145  and less than or equal to the thickness  106   b  of the body  105 . A second distance  150  between the bottom side  109  and the second blunt tip  141  may be approximately 0.05315 inches. A third distance  155  between the bottom side  109  and the second heal  149  may be approximately 0.0687 inches. A fourth distance  160  between the bottom side  109  and the second toe  148  may be approximately 0.0774 inches. A fifth distance  161  between the bottom side  109  and the second cutting edge  146  may be approximately 0.1496 inches. As depicted in  FIG. 1   b , the cutting edge  136   b  may be defined by a third sharpened portion  135   b   1  extending from a third shoulder  137   b   1  and a fourth sharpened portion  135   b   2  extending from a fourth shoulder  137   b   2 . It should be understood that either of the cutting edges  136 ,  146  may be formed similar to cutting edge  136   b . The sharpened portion  135 ,  145 , the third sharpened portion  135   b   1  and/or the fourth sharpened portion  135   b   2  may be substantially concave or convex shaped. Alternatively, a portion of the sharpened portion  135 ,  145 , a portion of the third sharpened portion  135   b   1  and/or a portion of the fourth sharpened portion  135   b   2  may be substantially concave or convex shaped with the remainder defining a linear shape. 
         [0032]    Turning to  FIG. 2 , a safety utility blade  200  is depicted proximate a human finger  265 . The safety utility blade  200  may be similar to the safety utility blade  100  of  FIGS. 1A and 1B  having a first sharpened portion  235  defining a first shoulder  237  and a first cutting edge  236 . As can be seen in  FIG. 2 , a first blade shield  230  may cooperate with the blade attachment portion  210  to limit access of the human finger  265  to the first cutting edge  236 . Similarly, the second blade shield  240  may cooperate with the blade attachment portion  210  to limit access to the second sharpened portion  245 . In either event, the safety utility blade  200  may be configured to limit access to associated cutting edges while the safety utility blade is being removed from an associated package, being inserted in a corresponding safety utility knife assembly (e.g., safety utility knife assembly  700  of  FIG. 7 ), when being removed from a corresponding safety utility knife assembly and while being used within a corresponding safety utility knife assembly. The safety utility blade  200  may have a body portion  205  constructed similar to the body portion  105 . The safety utility blade  200  may include blade securing holes  215 ,  220 ,  225  for securing the safety utility blade  200  to a corresponding safety cutting head (e.g., either safety cutting head  500   a  or  500   b  of  FIGS. 5A and 5B , respectively) or securing the safety utility blade to a handle (e.g., a handle  685  of  FIG. 6 ). 
         [0033]    With reference now to  FIGS. 3A-3D , a method  300   d  of manufacturing a safety utility blade (e.g., safety utility blade  100  of  FIG. 1 ) is described. A strip of blade material  300   a  is provided (block  370   d ). The individual rough blade shapes  301   a  may remain attached to one another while each of the individual steps  375   d - 385   d  are performed. A rough blade shape  301   a  is formed in the strip of blade material  300   a  (block  375   d ) by removing material  302   a ,  303   a ,  302   b ,  303   b . The material  302   a ,  303   a ,  302   b ,  303   b  may be removed from the strip of blade material  300   a  by laser cutting, machining, water jet cutting, stamp shearing or any other suitable technique. The material  302   c ,  303   c ,  302   d ,  303   d ,  302   e ,  303   e  may be removed prior to steps  380   d ,  385   d  being performed or the steps  380   d ,  385   d  may be performed on each rough blade shape  301   a  prior to removing the material  302   c ,  303   c ,  302   d ,  303   d ,  302   e ,  303   e  associated with the next rough blade shape  301   a . An edge (e.g., edge  111  and/or  112  of  FIG. 1 ) of the blade attachment portion  310   b  may form an angle  346   b  with respect to a blade bottom edge (e.g., bottom  109  of  FIG. 1 ) of approximately 21.2° to encourage material to be cut to move toward the blade end  347   b . The angle  346   b  may be between approximately 15° and approximately 25°. As can be seen in  FIG. 3A , each rough blade shape  301   a  may include a blade body portion  305   a ,  305   b ,  305   c ,  305   d  and a blade attachment portion  310   a ,  310   b ,  310   c ,  310   d . Blade securing holes  315   c ,  320   c ,  325   c ,  315   d ,  320   d ,  325   d  may be formed in each rough blade shape  301   a  (block  380   d ). The blade securing holes  315   c ,  320   c ,  325   c ,  315   d ,  320   d ,  325   d  may be formed by any suitable method, such as laser cutting, water jet cutting, machining, drilling, stamp shearing, etc. 
         [0034]    With further reference to  FIGS. 3A-3D , a first blade cutting edge  335   d  and a second blade cutting edge  345   d  may be formed in each rough blade shape  301   a  (block  385   d ). The first blade cutting edge  335   d  may be formed prior to the second blade cutting edge  345   d  or the first blade cutting edge  335   d  and the second blade cutting edge  345   d  may be formed simultaneously. The first blade cutting edge  335   d  and the second blade cutting edge  345   d  may be formed using a blade edge grinding and honing drum  385   b , a blade edge grinding and honing wheel  385   c  or any other suitable method. The blade edge grinding and honing drum  385   b  may have a radius  386   b  that is substantially the same as the desired cutting edge radius  304   a . The blade edge grinding and honing drum  385   b  may include a grinding surface  387   b  of any desired roughness and hardness to form the sharpened surface portion (e.g., sharpened surface portion  335   d ,  345   d ). As depicted in  FIG. 3B , the blade edge grinding and honing drum  385   b  may include a spindle  380   b  for attaching the blade edge grinding and honing drum  385   b  to an associated driving and actuating machine (not shown) to rotate the blade edge grinding and honing drum  385   b  or move the blade edge grinding and honing drum  385   b  in any combination of a x-direction  392   b , a y-direction  390   b  and a z-direction  393   b  relative to the strip of blade material  300   a  to produce a sharpened portion  135 ,  145 ,  135   b   1 ,  135   b   2 . Alternatively, the strip of blade material  300   a  may be oriented and moved in any one of or a combination of a x-direction  392   b , a y-direction  390   b  and a z-direction  393   b  relative to the blade edge grinding and honing drum  385   b  to produce a sharpened portion  135 ,  145 ,  135   b   1 ,  135   b   2 . The blade edge grinding and honing drum  385   b  may be rotated about a central axis  391   b  to produce a grinding and honing motion of the grinding surface  387   b  relative first blade cutting edge  335   d  and the second blade cutting edge  345   d . The blade edge grinding and honing drum  385   b  rotated into position around a pivot axis  394   b  when a corresponding rough blade shape  305   c  is moved into an appropriate position relative the blade edge grinding and honing drum  385   b.    
         [0035]    Alternatively, the first blade cutting edge  335   d  and the second blade cutting edge  345   d  may be formed using a blade edge grinding and honing wheel  385   c  or any other suitable method. The blade edge grinding and honing wheel  385   c  may have a radius  386   c  that is substantially the same as the desired cutting edge radius  304   a . The blade edge grinding and honing wheel  385   c  may include a grinding surface  387   c  of any desired roughness and hardness to form the sharpened surface portion (e.g., sharpened surface portion  335   d ,  345   d ). As depicted in  FIG. 3C , the blade edge grinding and honing wheel  385   c  may include a spindle  380   c  for attaching the blade edge grinding and honing wheel  385   c  to an associated driving and actuating machine (not shown) to rotate the blade edge grinding and honing wheel  385   c  and/or move the blade edge grinding and honing wheel  385   c  in any combination of a x-direction  392   c , a y-direction  390   c  and a z-direction  393   c  relative to the strip of blade material  300   a  to produce a sharpened portion  135 ,  145 ,  135   b   1 ,  135   b   2 . Alternatively, the strip of blade material  300   a  may be oriented and moved in any one of or a combination of a x-direction  392   c , a y-direction  390   c  and a z-direction  393   c  relative to the blade edge grinding and honing wheel  385   c  to produce a sharpened portion  135 ,  145 ,  135   b   1 ,  135   b   2 . The blade edge grinding and honing wheel  385   c  may be rotated about a central axis  391   c  to produce a grinding and honing motion of the grinding surface  387   c  relative first blade cutting edge  335   d  and the second blade cutting edge  345   d . The blade edge grinding and honing wheel  385   c  rotated into position around a pivot axis  394   c  when a corresponding rough blade shape  305   c  is moved into an appropriate position relative the blade edge grinding and honing wheel  385   c.    
         [0036]    Once the blade securing holes  315   c ,  320   c ,  325   c  and the sharpened surface portions  335   d ,  345   d  are formed in a respective rough blade shape  301   a , the finished safety utility blade  100  may be separated from the strip of blade material  300   a  (block  390   d ). Alternatively, with reference to FIGS.  3 E and  4 A- 4 D, a strip of blade material  300   a  may be provided (block  370   e ) and individual blade blanks  400   a  may be separated from the strip of blade material  300   a  (block  375   e ). Rough blade shapes  400   b  may be formed from the individual blade blanks  400   a  by laser cutting, machining, water jet cutting, stamp shearing or any other suitable technique (block  380   e ). The rough blade shapes may include a blade body portion  405   a ,  405   b ,  405   c ,  405   d  and a blade attachment portion  410   a ,  410   b ,  410   c ,  410   d . Blade securing holes  415   c ,  420   c ,  425   c ,  415   d ,  420   d ,  425   d  may be formed in the rough blade shapes by any suitable method, such as laser cutting, water jet cutting, machining, drilling, stamp shearing, etc. (block  385   e ). 
         [0037]    With further reference to FIGS.  3 E and  4 A- 4 D, a first blade cutting edge  435   d  and a second blade cutting edge  445   d  may be formed in each rough blade shape  400   a  (block  390   d ). The first blade cutting edge  435   d  may be formed prior to the second blade cutting edge  445   d  or the first blade cutting edge  435   d  and the second blade cutting edge  445   d  may be formed simultaneously. The first blade cutting edge  435   d  and the second blade cutting edge  445   d  may be formed using a blade edge grinding and honing drum  385   b , a blade edge grinding and honing wheel  385   c  or any other suitable method. The blade edge grinding and honing drum  385   b  may have a radius  386   b  that is substantially the same as the desired cutting edge radius  304   a . The blade edge grinding and honing drum  385   b  may include a grinding surface  387   b  of any desired roughness and hardness to form the sharpened surface portion (e.g., sharpened surface portion  435   d ,  445   d ). As depicted in  FIG. 3B , the blade edge grinding and honing drum  385   b  may include a spindle  380   b  for attaching the blade edge grinding and honing drum  385   b  to an associated driving and actuating machine (not shown) to rotate the blade edge grinding and honing drum  385   b  or move the blade edge grinding and honing drum  385   b  in any combination of a x-direction  392   b , a y-direction  390   b  and a z-direction  393   b  relative to the rough blade shape  400   b . Alternatively, the rough blade shape  400   b  may be oriented and moved in any one of or a combination of a x-direction  392   b , a y-direction  390   b  and a z-direction  393   b  relative to the blade edge grinding and honing drum  385   b.    
         [0038]    Alternatively, the first blade cutting edge  435   d  and the second blade cutting edge  445   d  may be formed using a blade edge grinding and honing wheel  385   c  or any other suitable method. The blade edge grinding and honing wheel  385   c  may have a radius  386   c  that is substantially the same as the desired cutting edge radius  304   a . The blade edge grinding and honing wheel  385   c  may include a grinding surface  387   c  of any desired roughness and hardness to form the sharpened surface portion (e.g., sharpened surface portion  435   d ,  445   d ). As depicted in  FIG. 3C , the blade edge grinding and honing wheel  385   c  may include a spindle  380   c  for attaching the blade edge grinding and honing wheel  385   c  to an associated driving and actuating machine (not shown) to rotate the blade edge grinding and honing wheel  385   c  and/or move the blade edge grinding and honing wheel  385   c  in any combination of a x-direction  392   c , a y-direction  390   c  and a z-direction  393   c  relative to the rough blade shape  400   b . Alternatively, the rough blade shape  400   b  may be oriented and moved in any one of or a combination of a x-direction  392   c , a y-direction  390   c  and a z-direction  393   c  relative to the blade edge grinding and honing wheel  385   c.    
         [0039]    Whether the safety utility blade  100  is completed prior to separating the rough blade shapes  301   a  from the strip of blade material  300   a  or the safety utility blade  100  is completed after the individual blade blanks  400   a  are separated from a strip of blade material  300   a , a series of grinding and honing drums  385   b  and/or grinding and honing wheels  385   c  may be used to form the sharpened surface portion  335   d ,  345   d ,  435   d ,  445   d . Each grinding and honing drum  385   b  and/or grinding and honing wheel  385   c  in a series of grinding and honing drums  385   b  and/or grinding and honing wheels  385   c  may have a progressively finer and finer grinding and honing surface  387   b ,  387   c  relative to the preceding grinding and honing drum  385   b  and/or grinding and honing wheel  385   c  in the series. 
         [0040]    Turning to  FIG. 5A , a safety cutting head  500   a  is depicted including a safety utility blade  501   a  attached to a handle adaptor  570   a . The safety utility blade  501   a  may include a blade body portion  505   a , an blade attachment portion  510   a , blade securing holes  515   a ,  520   a ,  525   a , a first sharpened portion  535   a , a first blade shield  530   a , a second sharpened portion  545   a  and a second blade shield  540   a . The handle adaptor  570   a  may include a body portion  565   a  having a first side  571   a  and a second side  572   a . As depicted in  FIG. 5A , the width of the body portion  565   a  may be substantially equal the width of the blade attachment portion  510   a . As also depicted in  FIG. 5A , the body portion  565   a  may extend beyond the blade body portion  505   a . The extension of the body portion  565   a  may cooperate with the securing holes  515   a ,  520   a ,  525   a  to secure the safety utility blade  501   a  to the handle adaptor  570   a . For example, the handle adaptor may be made of a thermal plastic material and may be co-molded around the safety utility blade  501   a  such that the thermal plastic material penetrates through the blade securing holes  515   a ,  520   a ,  525   a  and form a minor half of the body portion  565   a  on either side of the safety utility blade  501   a  to encapsulate the blade body portion  505   a  of the safety utility blade  501   a . The handle adaptor  570   a  may include a handle engagement portion  575   a  with a handle securing mechanism  580   a  to secure the safety cutting head  500   a  to a corresponding handle (e.g., handle  685  of  FIG. 6 ). 
         [0041]    Turning to  FIG. 5B , a safety cutting head  500   b  is depicted including a safety utility blade  501   b  attached to a handle adaptor  570   b . The safety utility blade  501   b  may include a blade body portion  505   b , an blade attachment portion  510   b , blade securing holes  515   b ,  520   b ,  525   b , a first sharpened portion  535   b , a first blade shield  530   b , a second sharpened portion  545   b  and a second blade shield  540   b . The handle adaptor  570   b  may include a body portion  565   a  having a first side  571   b  and a second side  572   b . As depicted in  FIG. 5A , the width of the body portion  565   b  may be substantially equal the width of the blade attachment portion  510   b . The body portion  565   b  may cooperate with the securing holes  515   b ,  520   b ,  525   b  to secure the safety utility blade  501   b  to the handle adaptor  570   b . For example, the handle adaptor may be made of a thermal plastic material and may be co-molded around the safety utility blade  501   b  such that the thermal plastic material penetrates through the blade securing holes  515   b ,  520   b ,  525   b  and form a minor half of the body portion  565   b  on either side of the safety utility blade  501   b  to encapsulate the blade body portion  505   b  of the safety utility blade  501   b . The handle adaptor  570   b  may include a handle engagement portion  575   b  with a handle securing mechanism  580   b  to secure the safety cutting head  500   b  to a corresponding handle (e.g., handle  685  of  FIG. 6 ). A first side  571   b  and a second side  572   b  of a handle adaptor  570   b  may cooperate with a body portion  565   b  to form a “clamshell” and fasteners, such as metal pins, may be included to cooperate with the securing holes  515   b ,  520   b ,  525   b  to replaceably secure a safety utility blade  100  within a safety cutting head  500   b . When a clamshell structure is provided, a handle engagement portion  575   b  may be configured with two halves with each halve being fixed to a respective side  571   b ,  572   b  of the handle adaptor  570   b . When a safety utility blade  100  is placed within a clamshell structure and the clamshell structure is engaged with a handle  685 , the safety utility blade  100  is secured within the clamshell structure of the safety cutting head  500   b . The body portion  565   b  may be configured as a hinge mechanism within a clamshell structure and fasteners, such as metal pins, may be fixed to a respective side  571   b ,  572   b  of the handle adaptor  570   b.    
         [0042]    Turning to  FIG. 6 , a safety cutting head  601  is depicted proximate an associated handle  685 . The safety cutting head  601  may include a first body side  602  and a second body side  603 . The safety cutting head  601  may include a handle engagement  675  having a handle securing mechanism  680 . The handle  685  may include a cutting head engagement  690  having a cutting head securing mechanism  695 . 
         [0043]    With reference now to  FIG. 7 , a safety utility knife assembly  700  is depicted including a safety cutting head  701  and a handle  785 . The safety cutting head  701  may include a first side  702  that aligns with a first handle side  776  and a second side  703  that aligns with a second handle side  777  when the handle engagement  775  is secured to the cutting head engagement  790  via the handle securing mechanism  780  and the cutting head securing mechanism  795 . A safety utility knife assembly  700  may be configured to store one or more additional safety cutting heads  701 . For example, a second safety cutting head  701  may be secured to each end of the handle  785 . Alternatively, the handle  785  may include a spare safety cutting head  701  retaining mechanism. 
         [0044]    Turning now to  FIGS. 8A-8H  and  8 J- 8 K, a safety utility knife assembly  800   a ,  800   b ,  800   c ,  800   d ,  800   e ,  800   f ,  800   g ,  800   h ,  800   j ,  800   k  is depicted including a blade  810   a ,  810   b ,  810   c ,  810   e ,  810   f ,  810   g ,  810   k  within a blade holder  805   a ,  805   b ,  805   c ,  805   d ,  805   e ,  805   f ,  805   g ,  805   j ,  805   j ,  805   k  inserted in a handle  815   a ,  815   b ,  815   c ,  815   d ,  815   e ,  815   f ,  815   g ,  815   h ,  815   j ,  815   k . The blade holder  805   a ,  805   b ,  805   c ,  805   d ,  805   e ,  805   f ,  805   g ,  805   j ,  805   j ,  805   k  may include a handle engagement  806   b ,  806   d ,  806   e ,  806   f ,  806   g ,  806   j  a blade retaining offset  808   e  and blade retainer  807   d ,  807   e . The handle  815   a ,  815   b ,  815   c ,  815   d ,  815   e  may include a blade holder engagement  816   b ,  816   e ,  816   f  that cooperates with the handle engagement  806   b ,  806   d ,  806   e ,  806   g ,  806   j  to secure the blade holder  805   a ,  805   b ,  805   c ,  805   d ,  805   e ,  805   f ,  805   g ,  805   j ,  805   j ,  805   k  within the handle  815   a ,  815   b ,  815   c ,  815   d ,  815   e ,  815   f ,  815   g ,  815   h ,  815   j ,  815   k . The blade retaining offset  808   e , a first blade retainer  807   d ,  807   e ,  807   f , a second blade retainer  808   f  and a third blade retainer  809   f  cooperate with the handle  815   a ,  815   b ,  815   c ,  815   d ,  815   e  to secure the blade edge  812   c ,  812   f  proximate a blade retaining offset surface  811   c ,  811   f . The safety utility knife assembly  800   a ,  800   b ,  800   c ,  800   d ,  800   e ,  800   f ,  800   g ,  800   h ,  800   j ,  800   k  may include a spare blade compartment to store unused blades  810   a ,  810   b ,  810   c ,  810   e ,  810   f ,  810   g ,  810   k.    
         [0045]    With reference to  FIGS. 9A-9H  and  9 J a blade holder  905   a ,  905   b ,  905   c ,  905   d ,  905   e ,  905   f ,  905   g ,  905   h ,  905   j  is depicted including a blade edge  912   b ,  912   e ,  912   f  of blade  910   a ,  910   b ,  910   c ,  910   d ,  910   e ,  910   f ,  910   g ,  910   h ,  910   j  secured against a blade retaining offset surface  911   b ,  911   e ,  911   f  of the blade holder  905   a ,  905   b ,  905   c ,  905   d ,  905   e ,  905   f ,  905   g ,  905   h ,  905   j  by a first blade retainer  907   a ,  907   b ,  907   c ,  907   e ,  907   j , a second blade retainer  908   a ,  908   b ,  908   c ,  908   e ,  908   j  and a third blade retainer  909   a ,  909   b ,  909   c ,  909   e ,  909   j . A blade holder head  920   a ,  920   b ,  920   c ,  920   d ,  920   e ,  920   f ,  920   g ,  920   h ,  920   j  and blade shield  925   a ,  925   b ,  925   f ,  925   j  are offset from the blade holder  905   a ,  905   b ,  905   c ,  905   d ,  905   e ,  905   f ,  905   g ,  905   h ,  905   j  at offset surface  921   a ,  921   b ,  921   c ,  921   e ,  921   f ,  921   g ,  921   j  by a distance substantially equal to a thickness (e.g., thickness  106   b  of  FIG. 1B ) of the blade  910   a ,  910   b ,  910   c ,  910   d ,  910   e ,  910   f ,  910   g ,  910   h ,  910   j . The blade holder  905   a ,  905   b ,  905   c ,  905   d ,  905   e ,  905   f ,  905   g ,  905   h ,  905   j  may include a first slide  922   a ,  922   b ,  922   c ,  922   e ,  922   f  and a second slide  923   a ,  923   b ,  923   e ,  923   f  that are received within a corresponding handle  815   a ,  815   b ,  815   c ,  815   d ,  815   e ,  815   f ,  815   g ,  815   h ,  815   j ,  815   k  and secured within the handle  815   a ,  815   b ,  815   c ,  815   d ,  815   e ,  815   f ,  815   g ,  815   h ,  815   j ,  815   k  with handle engagement mechanism  906   a ,  906   b ,  906   c ,  906   d ,  906   e ,  906   f  with biasing member  924   a ,  924   b ,  924   c ,  924   e ,  924   f . As depicted in  FIG. 9F , a blade throat  930   f  defines an angle  935   f  with respect to a longitudinal axis of the blade holder  905   f  of approximately 38°. The angle  935   f  may be between approximately 30° and approximately 45°. The blade throat  930   f  may define an angle  935   f  with respect to a longitudinal axis of the blade holder  905   f  between 25° and 50°. The blade throat  930   f  may be approximately 0.188 inches, thereby, the blade throat  930   f  limits exposure to the cutting edge of the blade  910   f . The cutting edge of the blade  910   f  may define an angle (e.g., angle  813   c  of  FIG. 8C ) with respect to a longitudinal axis of the blade holder  905   f  of approximately 20°. The cutting edge of the blade  910   f  may define an angle  813   c  with respect to a longitudinal axis of the blade holder  905   f  between 15° and 25°. 
         [0046]    Turning to  FIGS. 10A and 10E , a method  1000   e  of manufacturing a blade  1010   a   3  for use in a safety utility knife assembly (e.g. safety utility knife assembly  800   a  of  FIG. 8A ) may include providing a strip of blade material  1000   a  (block  1070   e ). A rough blade shape  1010   a   1  may be formed by removing material  1050   a  (block  1075   e ). Blade securing holes  1045   a   3 ,  1046   a   3 ,  1047   a   3  may be formed in the rough blade shape  1010   a   1  by any suitable method, such as laser cutting, water jet cutting, machining, drilling, stamp shearing, etc. (block  1080   e ). A sharpened portion  1040   a   2 ,  1040   a   3  may be formed by any suitable method, such as those disclosed in U.S. Pat. No. 4,265,055, 5,842,387, 6,860,796 or 8,206,199, for example (block  1085   e ). The sharpened portion  1040   a   2 ,  1040   a   3  may define a shoulder  1041   a   2 ,  1041   a   3  and a cutting edge  1042   a   2 ,  1042   a   3 . The blade  1010   a   3  may be separated from the strip of blade material  1000   a  by removing material  1052   a ,  1053   a  (block  1090   e ). A blade end  1051   a  may form an angle  1013   a  with respect to a linear edge of the strip of blade material  1000   a  of approximately 60°. The angle  1013   a  may be between approximately 55° and approximately 70°. 
         [0047]    With reference now to  FIGS. 10B-10D  and  10 F, a method  1000   f  of manufacturing a blade  1010   d  for use in a safety utility knife assembly (e.g. safety utility knife assembly  800   a  of  FIG. 8A ) may include providing a strip of blade material  1000   a  (block  1070   f ). Blade blanks  1000   b  may be formed from the strip of blade material  1000   a  (block  1075   f ). Rough blade shapes  1007   b  may be formed from the blade blanks  1000   b  (block  1080   f ). Blade securing holes  1045   b ,  1046   b ,  1047   b  may be formed in the rough blade shape  1000   b  by any suitable method, such as laser cutting, water jet cutting, machining, drilling, stamp shearing, etc. (block  1085   f ). A sharpened portion  1040   c ,  1040   d  may be formed by any suitable method, such as those disclosed in U.S. Pat. No. 4,265,055, 5,842,387, 6,860,796 or 8,206,199, for example (block  1090   f ). The sharpened portion  1040   c ,  1040   d  may define a shoulder  1041   c ,  1041   d  and a cutting edge  1042   c ,  1042   c.    
         [0048]    With reference to  FIG. 11 , a safety utility blade  1110  for use in the safety utility knife assembly  800   a  of  FIG. 8A  may have a body  1110   a  formed from a relatively thin and substantially flat material  1000   a , such as ceramic, heat treated carbon steel, ceramic coated steel, stainless steel, Teflon coated material, etc. For example, the material  1000   a  may be approximately 0.025 inches thick. A blade blank (e.g. blade blank  1000   a ,  1000   b  of  FIGS. 10A and 10B , respectively) may be 1.0964567 inches from a first end  1050   a  to a second end  1051   a  and 0.3917323 inches from a top side  1010   c  to a bottom side  1042   d . The safety utility blade may include blade securing holes  1115 ,  1120 ,  1125 . As described herein the blade securing holes  1115 ,  1120 ,  1125  may, at least in part, secure a safety utility blade  1110  to a safety utility knife cutting head (e.g., safety utility knife cutting head  920   j  of  FIG. 9J ). The safety utility blade  1110  may be formed from a suitable material  1000   a  for retaining a sharpened edge  1136 ,  1137 , and, when that material  1000   a  is metal, the body  1110   a  preferably has a thickness  106   b  of at least 0.0156 inches and preferably not greater than about 0.0313 inches. What might be characterized as a “heavy-duty” safety utility blade  100  is approximately 0.025 inches thick, and the thickness  106   b  for what might be characterized as a “regular duty” safety utility blade  1110  is approximately 0.017 inches. The sharpened portion  1135 ,  1145  is approximately 0.0492 inches high. 
         [0049]    With further reference to  FIG. 11 , the first sharpened portion  1135  of the safety utility blade  1110  may include a first shoulder  1137 , a first cutting edge  1136 , a first heal  1139  and a first toe  1138 . The safety utility blade may include a first edge  1111  extending from the first heal  1139  to the bottom side. The safety utility blade  1110  may further include a first inner edge  1133  that extends from the first toe  1139  to the bottom side and may have a thickness that is greater than the first sharpened portion  1135  and less than or equal to the thickness  106   b  of the body  1005   a . The first edge  1111  and the first inner edge  1133  may cooperate to limit access to the cutting edge  1136  while the safety utility blade  1110  is being used in the safety utility knife assembly  800   a , while the safety utility blade  1110  is being inserted into the safety utility knife assembly  800   a , while the safety utility blade  1110  is being removed from the safety utility knife assembly  800   a  and while the safety utility blade  1110  is being handled while removed from the safety utility knife assembly  800   a.    
         [0050]    With further reference to  FIG. 11 , the safety utility blade  1110  may include a second sharpened portion  1145  which may include a second shoulder  1147 , a second cutting edge  1146 , a second heal  1149  and a second toe  1148 . The safety utility blade  1110 ,  110   b  may include a second edge  1112  extending from the second heal  1149  to the bottom side. The safety utility blade  1110  may further include a second inner edge  1143  that extends from the second toe  1149  to the bottom side and may have a thickness that is greater than the second sharpened portion  1145  and less than or equal to the thickness  106   b  of the body  1005   a . As depicted in  FIG. 1   b , the cutting edge  136   b  may be defined by a third sharpened portion  135   b   1  extending from a third shoulder  137   b   1  and a fourth sharpened portion  135   b   2  extending from a fourth shoulder  137   b   2 . It should be understood that either of the cutting edges  1136 ,  1146  may be formed similar to cutting edge  136   b . The second edge  1112  and the second inner edge  1143  may cooperate to limit access to the cutting edge  1146  while the safety utility blade  1110  is being used in the safety utility knife assembly  800   a , while the safety utility blade  1110  is being inserted into the safety utility knife assembly  800   a , while the safety utility blade  1110  is being removed from the safety utility knife assembly  800   a  and while the safety utility blade  1110  is being handled while removed from the safety utility knife assembly  800   a . A safety utility blade  1110  may be manufactured similar to the safety utility blade  100  as described with reference to  FIGS. 3A-3E  and  4 A- 4 D. 
         [0051]    The figures depict preferred embodiments of safety blades for use in utility knife assemblies, utility knife assemblies and methods of manufacturing. One skilled in the art will readily recognize from the corresponding written description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles described. 
         [0052]    Upon reading this disclosure, those of skill in the art will appreciate still additional alternative structural and functional designs for safety blades for use in utility knife assemblies, utility knife assemblies and methods of manufacturing. Thus, while particular embodiments and applications have been illustrated and described, it is to be understood that the disclosed embodiments are not limited to the precise construction and components disclosed herein. Various modifications, changes and variations, which will be apparent to those skilled in the art, may be made in the arrangement, operation and details of the apparatuses and methods disclosed herein without departing from the spirit and scope defined in the appended claims.