Recip blade

Abstract

A recip blade has a cutting edge defining a cutting direction and a repeating pattern of cutting teeth. Each repeating pattern includes (i) a leading tooth with respect to the cutting direction that includes a rake face defining a first rake angle that is negative, and (ii) a trailing tooth following the leading tooth with respect to the cutting direction that includes a rake face defining a second rake angle that is less negative than the first rake angle.

What is claimed is: 
     
         1 . A recip blade comprising a cutting edge defining a cutting direction and a repeating pattern of cutting teeth, wherein each repeating pattern includes (i) a leading tooth with respect to the cutting direction that includes a rake face defining a first rake angle that is negative, and (ii) a trailing tooth following the leading tooth with respect to the cutting direction that includes a rake face defining a second rake angle that is less negative than the first rake angle. 
     
     
         2 . A recip blade as defined in  claim 1 , wherein the second rake angle is 0° or greater. 
     
     
         3 . A recip blade as defined in  claim 2 , wherein the first rake angle is within the range of about −1° and about −10°. 
     
     
         4 . A recip blade as defined in  claim 3 , wherein the first rake angle is within the range of about −2° and about −8°. 
     
     
         5 . A recip blade as defined in  claim 1 , wherein each repeating pattern includes at least two trailing teeth following the leading tooth, at least one trailing tooth is set to one side of the blade with respect to the cutting direction, and at least one other trailing tooth is set to an opposite side of the blade with respect to the cutting direction. 
     
     
         6 . A recip blade as defined in  claim 5 , wherein each repeating pattern includes two trailing teeth set to one side of the blade with respect to the cutting direction, and two trailing teeth set to an opposite side of the blade with respect to the cutting direction. 
     
     
         7 . A recip blade as defined in  claim 5 , wherein each repeating pattern includes two consecutive trailing teeth set to one side of the blade with respect to the cutting direction, and two consecutive trailing teeth set to an opposite side of the blade with respect to the cutting direction. 
     
     
         8 . A recip blade as defined in  claim 5 , wherein each repeating pattern includes a plurality of trailing teeth that are lower in height than the leading tooth. 
     
     
         9 . A recip blade as defined in  5 , wherein each leading tooth defines a first rake angle within the range of about −2° to about −8°, and each trailing tooth defines a second rake angle of about 0° or greater. 
     
     
         10 . A recip blade as defined in  claim 5 , wherein the leading tooth defines a relatively coarse pitch, and the trailing tooth defines a relatively fine pitch. 
     
     
         11 . A recip blade as defined in  claim 10 , wherein the finer the pitch of the trailing tooth, the more negative is the rake angle of the leading tooth. 
     
     
         12 . A recip blade as defined in  claim 11 , wherein each repeating pattern includes a plurality of trailing teeth defining a pitch within the range of about 21 TPI or finer, and the respective leading tooth defines a first rake angle within the range of about −6° to about −9°. 
     
     
         13 . A recip blade as defined in  claim 11 , wherein each repeating pattern includes a plurality of trailing teeth defining a pitch within the range of about 16 TPI to about 21 TPI, and the respective leading tooth defines a first rake angle within the range of about −4° to about −6°. 
     
     
         14 . A recip blade as defined in  claim 11 , wherein each repeating pattern includes a plurality of trailing teeth defining a pitch within the range of about 12 TPI to about 16 TPI, and the respective leading tooth defines a first rake angle within the range of about −1° to about −4°. 
     
     
         15 . A recip blade as defined in  claim 1 , wherein the leading tooth defines a first rake face, a first primary clearance surface, and a first included angle between the first rake face and first primary clearance surface, the trailing tooth defines a second rake face, a second primary clearance surface, and a second included angle between the second rake face and the second primary clearance surface, and the first included angle is greater than the second included angle. 
     
     
         16 . A recip blade as defined in  claim 15 , wherein the first primary clearance angle is greater than the second primary clearance angle. 
     
     
         17 . A recip blade as defined in  claim 16 , wherein each primary clearance surface defines a primary clearance angle within the range of about 35° to about 50°. 
     
     
         18 . A recip blade as defined in  claim 8 , wherein each repeating pattern includes a first unset leading tooth and a plurality of second set trailing teeth, and the set and unset teeth define a height differential prior to set within the range of about 0.002 inch to about 0.008 inch. 
     
     
         19 . A recip blade as defined in  claim 5 , wherein each repeating pattern includes a plurality of teeth set to a left side of the blade with respect to the cutting direction, a plurality of teeth set to a right side of the blade with respect to the cutting direction, the left set teeth include a relatively light set tooth and a relatively heavy set tooth, the right set teeth include a relatively light set tooth and a relatively heavy set tooth, and the relatively light set teeth are taller than the relatively heavy set teeth. 
     
     
         20 . A recip blade as defined in  claim 19 , wherein the height differential between the relatively light and heavy set teeth is within the range of about 0.002 inch to about 0.005 inch prior to set. 
     
     
         21 . A recip blade as defined in  claim 20 , wherein the relatively heavy set teeth define more positive rake angles than the relatively light set teeth. 
     
     
         22 . A recip blade as defined in  claim 7 , wherein each repeating pattern includes two consecutive trailing teeth set to a first side of the blade, a consecutive unset tooth trailing the two set teeth, and two consecutive teeth set to a second side of the blade opposite the first side and trailing the unset tooth. 
     
     
         23 . A recip blade as defined in  claim 22 , wherein all of the set teeth define the same level of set. 
     
     
         24 . A recip blade as defined in  claim 22 , wherein the two consecutive teeth set to the first side include a first relatively light set tooth followed by a second relatively heavy set tooth, and the two consecutive teeth set to the second side include a first relatively light set tooth followed by a second relatively heavy set tooth. 
     
     
         25 . A recip blade as defined in  claim 24 , wherein the relatively heavy set teeth have less negative rake angles than the relatively light set teeth. 
     
     
         26 . A recip blade as defined in  claim 24 , wherein each heavy set tooth defines a lower height than the respective light set tooth. 
     
     
         27 . A recip blade as defined in  claim 1 , wherein the repeating pattern extends from approximately one end of the cutting edge to another end. 
     
     
         28 . A recip blade for cutting a metal work piece comprising a cutting edge defining a cutting direction and a repeating pattern of cutting teeth, wherein each repeating pattern includes (i) first means for enhancing the life of the blade, and (ii) second means trailing the first means with respect to the cutting direction for substantially preventing or reducing the size of any burrs generated in cutting the metal work piece. 
     
     
         29 . A recip blade as defined in  claim 28 , wherein the first means is a leading tooth with respect to the cutting direction that includes a rake face defining a first rake angle that is negative, and the second means is a trailing tooth following the leading tooth with respect to the cutting direction that includes a rake face defining a second rake angle that is less negative than the first rake angle. 
     
     
         30 . A recip blade as defined in  claim 29 , wherein the second means is further defined by a plurality of said trailing teeth including at least one of said teeth set to one side of the blade with respect to the cutting direction and another of said teeth set to an opposite side of the blade with respect to the cutting direction.