Patent Publication Number: US-2015075013-A1

Title: Recip blade with rib, and method for manufacturing the same

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This patent application claims benefit under 35 U.S.C. §119 to U.S. Provisional Patent Application No. 61/879,821, which was filed on Sep. 19, 2013, and which is hereby incorporated by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     Aspects of the present invention relate to a recip blade, and a method for manufacturing the same. Aspects of the present invention more particularly relate to a recip blade that includes one or more ribs, and a method for manufacturing the same. 
     BACKGROUND 
     A recip blade has a “blade life” that corresponds to the number of cuts that the recip blade can perform before the recip blade fails. The blade life of a recip blade can depend at least in part on a stiffness of the recip blade. Prior art recip blades can be relatively flexible (i.e., relatively unstiff), and thus can have a blade life that is shorter in duration than desired. The stiffness of a recip blade (and thus the blade life of a recip blade) typically can be increased by increasing a thickness of the recip blade; however, a relatively thick recip blade can be undesirable for one or more reasons (e.g., increased cost and/or reduced cutting speed). 
     Aspects of the present invention are directed to these and other problems. 
     SUMMARY 
     According to an aspect of the present invention, a recip blade includes a blade body, a tang, a distal end, a cutting edge, and a rib. The tang is located an end of the blade body. The distal end is located at an opposite end of the blade body relative to the tang. The cutting edge extends in a lengthwise direction at least substantially between the tang and the distal end. The rib extends along at least a portion of the blade body. The rib and the cutting edge are spaced from one another by a heightwise-extending distance. 
     According to another aspect of the present invention, a recip blade includes a blade body, a tang, a distal end, and a cutting edge. The tang is located at an end of the blade body. The distal end is located at an opposite end of the blade body relative to the tang. The cutting edge extends in a lengthwise direction at least substantially between the tang and the distal end. The recip blade further includes means extending along at least a portion of the blade body for increasing a widthwise-extending thickness of the blade body at the means in comparison to a widthwise-extending thickness of the blade body at an adjacent portion of the blade body. The means and the cutting edge are spaced from one another by a heightwise-extending distance. 
     According to another aspect of the present invention, a method includes: (i) providing a recip blade having a blade body, a tang located at an end of the blade body, a distal end located at an opposite end of the blade body relative to the tang, and a cutting edge extending in a lengthwise direction at least substantially between the tang and the distal end; and (ii) forming a rib extending along at least a portion of the blade body and being spaced from the cutting edge by a heightwise-extending distance. The forming step is performed by increasing a widthwise-extending thickness of the blade body at the rib in comparison to a widthwise-extending thickness of the blade body at an adjacent portion of the blade body. In some embodiments, the recip blade provided in the providing step further includes a backbone that extends in a lengthwise direction along an opposite side of the blade body relative to the cutting edge; and the forming step further includes forming an upset in the blade body, which upset at least partially defines the rib. 
     In addition to, or as an alternative to, one or more of the features described above, further aspects of the present invention can include one or more of the following features, individually or in combination:
         the cutting edge is configured to cut metal and/or wood;   the rib is a first rib, the recip blade further comprises one or more second ribs, and the first rib and the one or more second ribs are spaced from one another by one or more lengthwise-extending distances;   the rib is at least partially defined by an upset which increases a widthwise-extending thickness of the blade body at the rib in comparison to a widthwise-extending thickness of the blade body in at least an adjacent portion of the blade body;   the widthwise-extending thickness of the blade body at the rib is at least about 10% greater than the thickness of the blade body at the adjacent portion of the blade body;   the widthwise-extending thickness of the blade body at the rib is at least about 20% greater than the thickness of the blade body at the adjacent portion of the blade body;   the widthwise-extending thickness of the blade body at the rib is at least about 30% greater than the thickness of the blade body at the adjacent portion of the blade body;   the rib is at least partially defined by an upset which increases a widthwise-extending thickness of the blade body at the rib in comparison to a widthwise-extending thickness of an at least substantial remainder of the blade body;   the widthwise-extending thickness of the blade body at the rib is at least about 10% greater than the thickness of the blade body at the at least substantial remainder of the blade body;   the widthwise-extending thickness of the blade body at the rib is at least about 20% greater than the thickness of the blade body at the at least substantial remainder of the blade body;   the widthwise-extending thickness of the blade body at the rib is at least about 30% greater than the thickness of the blade body at the at least substantial remainder of the blade body;   the rib defines a structural surface, a supporting surface, a raised strip, a raised ridge, and/or a raised surface area extending along at least the portion of the blade body;   the blade body includes a first side surface and an opposing second side surface, the rib extends in a first widthwise direction relative to the first side surface of the blade body, and the rib extends in an opposing second widthwise direction relative to the second side surface of the blade body;   the rib extends along at least one-half (½) of a length of the blade body;   the rib extends along at least three-quarters (¾) of a length of the blade body;   the rib extends along at least seventh-eighths (⅞) of a length of the blade body;   the rib extends along at least substantially an entirety of a length of the blade body;   the blade body further defines a backbone that extends in a lengthwise direction along an opposite side of the blade body relative to the cutting edge, and the backbone defines a backbone length;   the rib extends along at least substantially an entirety of the backbone length;   the rib is a first rib, the recip blade further comprises one or more second ribs, the first rib and the one or more second ribs are spaced from one another by one or more lengthwise-extending distances, and the first rib and the one or more second ribs collectively extend along at least one-half (½) of the backbone length;   the first rib and the one or more second ribs collectively extend along at least three-quarters (¾) of the backbone length.   the first rib and the one or more second ribs collectively extend along at least seven-eights (⅞) of the backbone length.   the rib has a rib width that is not greater than a kerf width of the cutting edge;   the rib width is less than the kerf width;   the rib is located within the kerf width; and   the cutting edge includes a plurality of teeth, and at least some of the plurality of teeth are alternatingly set in opposite widthwise-extending directions outwardly from a lengthwise-extending centerline of the recip blade.       

     One advantage of the present invention and/or of the currently preferred embodiments thereof is that the at least one rib increases the stiffness of the recip blade which can, in turn, increase blade life. Yet another advantage is that the stiffness of the blade can be increased by increasing the cross-sectional thickness of the blade body material only at the rib but not at the other portions of the blade body. 
     These and other aspects of the present invention will become apparent in light of the drawings and detailed description provided below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side elevation view of an embodiment of the present recip blade. 
         FIG. 2  is a somewhat schematic cross-sectional view of the recip blade of  FIG. 1 . 
         FIG. 3  is a somewhat schematic cross-sectional view of another embodiment of the present recip blade. 
         FIG. 4  is a somewhat schematic top plan view of a portion of the recip blade of  FIG. 1 . 
         FIG. 5  is an elevation view of another embodiment of the present recip blade. 
         FIG. 6  is a graph illustrating test data showing the improved blade life of a recip blade of the present invention over a control recip blade. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure describes a recip blade  10  (see  FIGS. 1 and 5 ), and a method for manufacturing the same. 
     The present disclosure describes aspects of the present invention with reference to the exemplary embodiments illustrated in the drawings; however, aspects of the present invention are not limited to the exemplary embodiments illustrated in the drawings. The present disclosure may describe one or more features as having a length extending relative to an x-axis, a width extending relative to a y-axis, or a height extending relative to a z-axis. The drawings illustrate the respective axes as necessary. There is no relationship between the axes and the direction of gravity. 
     Referring to  FIGS. 1 and 5 , the present recip blade  10  includes a blade body  12 , a tang  14  located at one end of the blade body  12 , a distal end  16  located at an opposite end of the blade body  12  relative to the tang  14 , a cutting edge  18  extending in a lengthwise direction at least substantially between the tang  14  and the distal end  16 , and one or more ribs  20 ,  21  extending along at least a portion of the blade body  12 . The ribs  20 ,  21  and the cutting edge  18  are spaced from one another by one or more heightwise-extending distances. 
     The tang  14  is positioned at a “tang angle” (not shown) relative to the blade body  12 . In some embodiments, including the illustrated embodiments, the tang angle is greater than zero degrees (e.g., within a range of about three degrees to seven degrees). This feature can cause the cutting edge  18  of the recip blade  10  to enter a work piece at an angle different than that otherwise defined by a plane of the cutting edge  18 , and can thereby allow the recip blade  10  to remain aggressive with deep penetration in a cut for more efficient cutting. In other embodiments (not shown), the tang angle is at least substantially equal to zero degrees. 
     The cutting edge  18  can be configured to cut various different materials. In the illustrated embodiments, the cutting edge  18  is configured to cut metal and/or wood. In other embodiments (not shown), the cutting edge  18  may additionally or alternatively be configured to cut any other material that is currently known, or that may later become known. 
     The cutting edge  18  includes a plurality of teeth. In some embodiments, at least some of the teeth are alternatingly set in opposite widthwise-extending directions outwardly from a lengthwise-extending centerline of the recip blade  10 . The cross-sectional views of  FIGS. 2 and 3  each illustrate only a single tooth that is substantially aligned with a lengthwise-extending centerline (not shown) of the recip blade  10 ; however, in the illustrated embodiments, some of the teeth are alternatingly set in opposite widthwise-extending directions outwardly from the lengthwise-extending centerline of the recip blade  10 . 
     The number of ribs  20 ,  21  included in the recip blade  10  can vary. In some embodiments (see  FIG. 1 ), the recip blade  10  includes only one rib  20 . In other embodiments (see  FIG. 5 ), the recip blade  10  includes two ribs  20 ,  21 . In still other embodiments (not shown), the recip blade  10  includes more than two ribs  20 ,  21 . In embodiments in which the recip blade  10  includes more than one rib  20 ,  21  (see  FIG. 5 ), the ribs  20 ,  21  can be spaced from one another by one or more lengthwise-extending distances. In the embodiment illustrated in  FIG. 5 , for example, the two ribs  20 ,  21  are spaced from one another by a lengthwise-extending distance  23 . 
     The one or more ribs  20 ,  21  each are defined at least partially by an upset (or an area of upset) of the blade body  12  that increases (e.g., sharply increases (see  FIG. 2 ), gradually increases (see  FIG. 3 )) one or more widthwise-extending thicknesses of the blade body  12  at the ribs  20 ,  21  in comparison to a widthwise-extending thickness of the blade body  12  at an adjacent portion of the blade body  12 . In some embodiments, the ribs  20 ,  21  are defined at least partially by an upset (or an area of upset) that increases one or more widthwise-extending thicknesses of the blade body  12  at the ribs  20 ,  21  in comparison to one or more widthwise-extending thicknesses of at least a substantial remainder of the blade body  12 . By increasing one or more widthwise-extending thicknesses of the blade body  12  at the ribs  20 ,  21 , the ribs  20 ,  21  thereby increase a stiffness of the blade body  12  (and thus increase the blade life of the recip blade  10 ) in comparison to prior art recip blades that do not include one or more ribs. 
     In some embodiments, the respective thicknesses of the material of the blade body  12  at the one or more ribs  20 ,  21  is at least about ten percent (10%) greater than a widthwise-extending thickness of the material of the blade body  12  at an adjacent portion of the blade body  12 . In other embodiments, the respective thicknesses of the material of the blade body  12  at the ribs  20 ,  21  is at least about twenty percent (20%) greater than a widthwise-extending thickness of the material of the blade body  12  at an adjacent portion of the blade body  12 . In still other embodiments, the respective thicknesses of the material of the blade body  12  at the ribs  20 ,  21  is at least about thirty percent (30%) greater than a widthwise-extending thickness of the material of the blade body  12  at an adjacent portion of the blade body  12 . 
     The one or more ribs  20 ,  21  can each be configured in various different ways. For example, the ribs  20 ,  21  can each be a structural or supporting surface, a raised strip or ridge, and/or another relatively raised surface area extending along at least a portion of the blade body  12 . Referring to  FIGS. 2 and 3 , in the illustrated embodiments, the blade body  12  includes a first side surface and an opposing second side surface, the rib  20  extends in a first widthwise direction relative to the first side surface of the blade body  12 , and the rib  20  extends in an opposing second widthwise direction relative to the second side surface of the blade body  12 . Although not shown in the drawings, the ribs  20 ,  21  of the embodiment illustrated in  FIG. 5  are configured similar to the rib  20  of the embodiment illustrated in  FIG. 2 . 
     The one or more ribs  20 ,  21  collectively extend along at least one-half (½) of a length “L” of the blade body  12 . In some embodiments, the ribs  20 ,  21  collectively extend along at least about three-quarters (¾) of the length “L” of the blade body  12 . In other embodiments, the ribs  20 ,  21  collectively extend along at least about seventh-eighths (⅞) of the length “L” of the blade body  12 . In still other embodiments, the ribs  20 ,  21  collectively extend along at least substantially the entire length “L” of the blade body  12 . 
     Referring to  FIGS. 1-5 , in some embodiments, the blade body  12  further defines a backbone  22  that extends in a lengthwise direction along an opposite side of the blade body  12  relative to the cutting edge  18 . In such embodiments, the backbone  22  defines a length “L2.” In some embodiments in which the recip blade  10  includes only one rib  20 , the rib  20  extends along at least substantially the entire length “L2” of the backbone  22 . Referring to  FIG. 1 , in the illustrated embodiment, the rib  20  extends along substantially the entire length “L2” of the backbone  22 . In some embodiments in which the recip blade  10  includes more than one rib  20 ,  21 , the ribs  20 ,  21  collectively extend along at least about one-half (½) of the length “L2” of the backbone  22 . In other such embodiments, the ribs  20 ,  21  collectively extend along at least about three-quarters (¾) of the length “L2” of the backbone  22 . In still other such embodiments, the ribs  20 ,  21  collectively extend along at least about seven-eights (⅞) of the length “L2” of the backbone  22 . Referring to  FIG. 5 , in the illustrated embodiment, the two ribs  20 ,  21  collectively extend along at least about seven-eights (⅞) of the length “L2” of the backbone  22 . 
     The one or more ribs  20 ,  21  each have a width that is not greater than, and in some embodiments is less than, the kerf width “KW” of the cutting edge  18 . Referring to  FIG. 4 , in the illustrated embodiment, the cutting edge  18  defines a kerf width “KW,” the rib  20  defines a rib width “RW,” and the rib width “RW” is less than the kerf width “KW,” such that the rib  20  is “located within” the kerf width “KW.” This is due at least in part to the fact that some of the teeth are alternatingly set in opposite widthwise-extending directions outwardly from the lengthwise-extending centerline of the recip blade  10 , as described above. 
     Referring to  FIG. 6 , the respective blade lives of a present recip blade  10  and a prior art control recip blade were tested. The prior art control recip blade did not include one or more ribs. The blade lives of the respective recip blades were tested by cutting steel electromechanical tubing (“EMT”) having a diameter of one and one-half inches (1½ in.). In the graph of  FIG. 6 , the vertical axis corresponds to the number of cuts performed by the respective recip blades prior to failure. The first data set  24  toward the left side of the graph plots measured blade lives of the prior art control recip blade, and the second data set  26  toward the right side of the graph plots measured blade lives of the present recip blade  10 . The data point  28  in the first data set  24  indicates that the control recip blade made, on average, approximately ninety-six (96) cuts prior to failure. The data point  30  in the second data set  26  indicates that the present recip blade  10  made, on average, approximately one hundred fifteen (115) cuts prior to failure. Accordingly, the present recip blade  10  exhibited an approximately twenty percent (20%) increase in blade life over the prior art control blade. This was a surprising and unexpected result, and the increase in blade life is believed to be attributed to one or more of the above-described features of present recip blade  10 . 
     The present recip blade  10  can be manufactured in accordance with the following procedural steps:
         i. A bi-metal strip (not shown) is formed by welding (e.g., by electron beam welding) a high-speed steel portion to a spring steel backing;   ii. A cutting edge is then formed by milling teeth into the high speed steel portion of the bi-metal strip;   iii. The cutting teeth of the cutting edge are then set in accordance with any desired set pattern;   iv. The bi-metal strip is then fed through a hardening furnace to harden;   v. The bi-metal strip is then heated again (e.g., with one or more induction heaters) to soften the strip, at least at portions of the strip from which the ends of the respective recip blades  10  are to be formed;   vi. The bi-metal strip is cut (e.g., with a die) at the heated and softened portions of the strip, to form individual recip blades  10  from the strip;   vii. The individual recip blades  10  are then tempered (e.g., by stacking them in trays and placing them in a tempering furnace); and   viii. The tempered recip blades  10  are then painted (if desired), and then packaged and shipped.       

     In embodiments in which the present recip blade  10  is manufactured in accordance with the above-described procedural steps, the one or more ribs  20 ,  21  are formed either (1) in the bi-metal strip, before hardening; or (2) in the individual recip blade  10 , after the individual recip blade  10  is cut from the bi-metal strip, but before tempering. In some embodiments, the ribs  20 ,  21  are formed by roll-forming the backbone  22 , which thereby forms the upset (or area of upset) that defines the ribs  20 ,  21 . 
     While several embodiments have been disclosed, it will be apparent to those of ordinary skill in the art that aspects of the present invention include many more embodiments and implementations. Accordingly, aspects of the present invention are not to be restricted except in light of the attached claims and their equivalents. It will also be apparent to those of ordinary skill in the art that variations and modifications can be made without departing from the true scope of the present disclosure. For example, it should be noted that the rib(s) can be orientated in any direction or combinations thereof. In addition, other shapes or structural deformations can be formed in place of or in addition to the rib(s) as shown to increase the cross-sectional thickness of the blade material at the rib(s) and/or to otherwise increase the stiffness of the blade. In some instances, one or more features disclosed in connection with one embodiment can be used alone or in combination with one or more features of one or more other embodiments.