Patent Publication Number: US-2022234124-A1

Title: Accessories for oscillating power tools

Description:
RELATED APPLICATION 
     This application claims priority, under 35 U.S.C. § 119(e) to U.S. Provisional Application No. 63/140,581, filed Jan. 22, 2021, titled “Accessories for Oscillating Power Tools,” which is incorporated by reference. 
    
    
     TECHNICAL FIELD 
     This application relates to accessories (such as cutting tools and saw blades) for oscillating power tools. 
     BACKGROUND 
     Oscillating power tools generally have a motor, an output shaft, and a transmission that connects the motor to the output shaft and converts rotary motion of the motor to oscillating motion of the output shaft. The output shaft is coupled to an accessory attachment mechanism that is used to removably attach various types of accessories, such as cutting tools, saw blades, and sanding tools, to the output shaft. It is desirable to have oscillating accessories for performing variety of tasks. 
     SUMMARY 
     In an aspect, an accessory for use with oscillating power tools includes an attachment portion with a rear end configured to be coupled to the oscillating power tool and a working portion coupled to the attachment portion and extending along an axis. The working portion includes a body bounded at least partially by a front cutting edge with a plurality of teeth opposite the rear end, a first lateral non-cutting edge extending from a first end of the front cutting edge toward the rear end, and a second lateral non-cutting edge opposite the first lateral non-cutting edge and extending from a second end of the front cutting edge toward the rear end. The front cutting edge is arranged asymmetrically relative to the axis with a leading tooth disposed on one side of the axis at a first distance from the rear end of the working portion and a trailing tooth disposed on an opposite side of the axis at a second distance from the rear end of the working portion that is less than the first distance. 
     Implementations of this aspect may include one or more of the following features. The first distance may be greater than or equal to a distance from all other teeth to the rear end. The second distance may be less than or equal to a distance from all other teeth to the rear end. The leading tooth and the trailing tooth may be at opposite ends of the cutting edge. The teeth may be arranged in a convex arc-shaped pattern along a curve. The curve may have a radius that is centered at a center point on one side of the axis. The center point may be disposed axially rearward of on the attachment portion about which the accessory oscillates during use. The plurality of teeth may be arranged along a straight line at an acute angle relative to the axis. 
     In another aspect, an accessory for use with oscillating power tools includes an attachment portion with a rear end configured to be coupled to the oscillating power tool and a working portion coupled to the attachment portion and extending along an axis. The working portion includes a body bounded at least partially by a front cutting edge with a plurality of teeth opposite the rear end, a first lateral non-cutting edge extending from a first end of the front cutting edge toward the rear end, and a second lateral non-cutting edge opposite the first lateral non-cutting edge and extending from a second end of the front cutting edge toward the rear end. The plurality of teeth includes a first subset of teeth extending from the first lateral edge toward the axis, a second subset of teeth extending from the second lateral edge toward the axis, and a third subset of teeth disposed between the first subset of teeth and the second subset of teeth and intersecting the axis. The first and second subsets of teeth have the same size, shape, configuration, and spacing, while the third subset of teeth has a different size, shape, configuration, and/or spacing than the first and second subset of teeth. 
     Implementations of this aspect may include one or more of the following features. The first and second subsets of teeth may be triangular with a coarse tooth pitch and the third subset of teeth may be triangular with a fine tooth pitch. The transition between the subsets may be gradual or sudden. 
     In another aspect, an accessory for use with oscillating power tools includes an attachment portion with a rear end configured to be coupled to the oscillating power tool and a working portion coupled to the attachment portion and extending along an axis. The working portion includes a body bounded at least partially by a front cutting edge with a plurality of teeth opposite the rear end, a first lateral non-cutting edge extending from a first end of the front cutting edge toward the rear end, and a second lateral non-cutting edge opposite the first lateral non-cutting edge and extending from a second end of the front cutting edge toward the rear end. The plurality of teeth alternate between a first tooth and a second tooth that are different from each other. 
     Implementations of this aspect may include one or more of the following features. The first tooth may be a triangular tooth having a first rake face at a larger first rake angle facing toward the first lateral edge and a second rake face at a smaller second rake angle facing toward the second lateral edge. The second tooth may be a triangular tooth having a third rake face at a larger third rake angle facing toward the second lateral edge and a fourth rake face at a smaller fourth rake angle facing toward the second lateral edge. The first and second teeth may be mirror images of each other. The first and third rake angles may be the same and the second and fourth rake angles may be the same. The first and second teeth may be separated by alternating first and second gullets. Each first gullet may be disposed between first and third rake faces and have a larger first width and a larger first included angle. Each second gullet may be disposed between second and fourth rake faces and have a smaller first width and a smaller first included angle. The teeth may alternate in pitch and spacing. The first tooth may be a symmetrical triangular tooth having a first rake face and a second rake face each at a first rake angle relative to the axis. The second tooth may be a symmetrical triangular tooth having a third rake face and a fourth rake face each at a second rake angle relative to the axis that is different (e.g., larger) than the first rake angle. The first and second teeth may be separated by alternating first and second gullets that are mirror images of one another and that each have the same included angle and each having the same width. The teeth may alternate in rake angle and size, while being spaced at a constant spacing or pitch. 
     In another aspect, an accessory for use with oscillating power tools includes an attachment portion with a rear end configured to be coupled to the oscillating power tool and a working portion coupled to the attachment portion and extending along an axis. The working portion includes a body bounded at least partially by a front cutting edge with a plurality of teeth opposite the rear end, a first lateral non-cutting edge extending from a first end of the front cutting edge toward the rear end, and a second lateral non-cutting edge opposite the first lateral non-cutting edge and extending from a second end of the front cutting edge toward the rear end. The front cutting edge includes one or more center teeth each having a symmetrical shape, a first group of asymmetric teeth arranged between the first lateral edge and the one or more center teeth and a second group of asymmetric teeth arranged between the second lateral edge and the at least one center teeth. 
     Implementations of this aspect may include one or more of the following features. The one or more center teeth may include one or more symmetrical triangular teeth. The first group of teeth and the second group of teeth may be mirror images of one another. Each tooth in the first and second group may have a rake face that is generally parallel to the axis and a relief face  638  at an acute relief angle to a line parallel to the cutting edge. Between each of the teeth in the first and second groups may be a generally U-shaped gullet having a height. The tips of adjacent teeth in the first and second groups may be spaced apart by a pitch distance. The rake faces of the teeth on the first and second groups may face outwardly toward the lateral edges or may face inwardly toward the axis. 
     In another aspect, an accessory for use with oscillating power tools includes an attachment portion with a rear end configured to be coupled to the oscillating power tool, and a working portion coupled to the attachment portion and extending along an tool axis. The working portion includes a body bounded at least partially by a front cutting edge opposite the rear end, a first lateral edge extending from the front cutting edge toward the rear end, and a second lateral edge opposite the first lateral edge and extending from the front cutting edge toward the rear end. The front cutting edge is arranged asymmetrically relative to the tool axis with a leading tooth disposed at one end of the cutting edge at a first distance from the rear end, a trailing tooth disposed on an opposite end of the cutting edge at a second distance from the rear end that is less than the first distance, and a plurality of intermediate teeth disposed between leading tooth and the trailing tooth and each being disposed less than or equal to the first distance from the rear end of the working portion and greater than or equal to the second distance from the rear end of the working portion, cutting edge slanted at an acute angle to a line that is perpendicular to the tool axis. 
     Implementations of this aspect may include one or more of the following features. The first distance may be greater than or equal to a distance from all other teeth to the rear end. The second distance may be less than or equal to a distance from all other teeth to the rear end. The cutting edge may include a plurality of teeth arranged in a convex arc shape along a curve. The curve may have a radius that is centered at a center point on one side of the tool axis. The center point may be disposed axially rearward of the attachment portion. A tangent line to the cutting edge at each tooth may be disposed at an acute angle to the line that is perpendicular to the blade axis X. The acute angle may progressively increase from the leading tooth to the trailing tooth. The acute angle of the tangent line at each tooth may be between 0° and 15°. An average of the acute angles may be between 3° and 10°. The acute angle of the tangent line to a center tooth on the cutting edge at the tool axis may be at between 3° and 10°. 
     The cutting edge may include a plurality of teeth arranged along a straight line arranged at the acute angle relative to the line perpendicular to the tool axis. The acute angle may be between 3° and 10°. The cutting edge may be formed as a cutting edge portion composed of a harder material than the body. The cutting edge portion may be coupled to a front end of the body by welding, brazing, or adhesive. The body may be composed of a first metal and the front cutting edge portion is composed of high speed steel, M42 steel, Matrix 2 steel, or a carbide material. The cutting edge may include a plurality of teeth that alternate between a first tooth and a second tooth that are different from each other. Each first tooth is a triangular tooth may have a first rake face at a first rake angle facing toward the first lateral edge and a second rake face facing toward the second lateral edge at a second rake angle that is smaller than the first rake angle, and each second tooth may have a third rake face facing toward the second lateral edge at a third rake angle that is equal to the first rake angle and a fourth rake face facing toward the first lateral edge at a fourth rake angle that is equal to the second rake angle. The cutting edge may include one or more central teeth each having a symmetrical shape, a first group of asymmetric teeth arranged between the first lateral edge and the one or more central teeth and a second group of asymmetric teeth arranged between the second lateral edge and the at least one central teeth. The one or more central teeth may include one or more symmetrical triangular teeth, the first group of teeth each having a rake face that is parallel to the tool axis and a relief face at an acute relief angle to the tool axis, and the second group of teeth each having a rake face that is parallel to the tool axis and a relief face at an acute relief angle to the tool axis. 
     Advantages may include one or more of the following. The oscillating accessories may have improved durability, life, and/or cutting speed, including when cutting wood embedded with one or more nails or other metal pieces. These and other advantages and features will be apparent from this application. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a perspective view an oscillating power tool having an implementation of an accessory attachment mechanism. 
         FIG. 1B  a perspective view of a clamping plate of the attachment mechanism of  FIG. 1A . 
         FIG. 2A  is a top view of an implementation of an accessory for use with an oscillating power tool. 
         FIG. 2B  is a side view of the accessory of  FIG. 2A . 
         FIG. 2C  is a close-up view of the cutting edge of the accessory of  FIG. 2A . 
         FIGS. 2D, 2E, and 2F  are schematic views of the accessory of  FIG. 2A  during operation. 
         FIG. 3A  is a top view of another implementation of an accessory for use with an oscillating power tool. 
         FIG. 3B  is a close-up view of the cutting edge of the accessory of  FIG. 3A . 
         FIGS. 3C, 3D, and 3E  are schematic views of the accessory of  FIG. 3A  during operation. 
         FIG. 4A  is a top view of another implementation of an accessory for use with an oscillating power tool. 
         FIG. 4B  is a close-up view of the cutting edge of the accessory of  FIG. 4A . 
         FIG. 5A  is a top view of another implementation of an accessory for use with an oscillating power tool. 
         FIG. 5B  is a close-up view of the cutting edge of the accessory of  FIG. 5A . 
         FIG. 5C  is a close-up view of a cutting edge of another implementation of an accessory for use with an oscillating power tool 
         FIG. 6A  is a top view of another implementation of an accessory for use with an oscillating power tool. 
         FIG. 6B  is a close-up view of the cutting edge of the accessory of  FIG. 6A . 
         FIG. 7  is a close-up view of a cutting edge of another implementation of an accessory for use with an oscillating power tool. 
         FIG. 8  is a close-up view of a cutting edge of another implementation of an accessory for use with an oscillating power tool. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1A and 1B , in an implementation, an oscillating power tool  12  usable with the accessories described in this application is similar to oscillating power tools sold under the brand names DEWALT® and Porter-Cable® and is described further in U.S. Pat. No. 8,925,931, which is hereby incorporated by reference. The power tool  12  includes a tool body  18  including a housing  20  that contains a motor  22  to drive an output member  24 . An output spindle  26  is coupled to the motor  22  via a transmission  25  that converts rotary motion of the motor  22  to oscillating motion of the spindle  26 . The output of the spindle  26  is coupled to an accessory attachment mechanism  10  via an output shaft  102 . The accessory attachment mechanism  10  is configured to receive an accessory  100  (such as a saw blade, rasp, abrasive, etc.) and does not require the use of a separate tool to couple the accessory to the oscillating power tool (also known as a “tool-free” attachment mechanism). An exemplary tool-free attachment mechanism  10  includes a clamp assembly  30  having a first clamp member  36  fixedly coupled to the output spindle, a second clamp member  38  facing the first clamp member  36 , and a lever  32  coupled to the second clamp member  38 . The lever  32  includes a lever arm  40  with a user engagement portion  42  and a block  44 . The lever  32  further includes a pivot portion  46  having a pivot axle  48 . The second clamp member  38  includes a second clamp body  70  generally in the form of a ring having a central opening  72 . The second clamp body  70  has a second clamping surface  74  having a plurality of mounting features  76  formed thereon. In the example shown, the plurality of mounting features  76  are in the form of male projections  78 . In the particular example shown, the eight male projections  78  each have a circular cross section and a tapered shape or form. In another related implementation, the male projections may have an oblong, oval, or rectangular cross-section and may also be tapered. In other implementations, the accessory  100  may be configured for use with or adapted for use with other oscillating power tools and accessory mounting mechanisms for oscillating power tools, such as those disclosed in U.S. patent application Ser. Nos. 16/511,043; 15/893,610; 15/253,559; 15/065,024; 14/909,233; 14/909,247; and Ser. No. 12/798,997; and U.S. Pat. Nos. 10,350,721; 10,137,592; 10,040,215; 9,670,998; 9,272,435; 9,346,183; 8,585,469; 8,182,316, each of which is incorporated by reference. Several implementations of accessories that can be coupled to the accessory attachment mechanism  10  are described below. 
     Referring to  FIGS. 2A-2C , an implementation of an oscillating accessory  200  includes a working portion  202  with a front end  203  and an attachment portion  204  with a rear end  210 . In one implementation, the attachment portion  204  includes a plurality of recesses or openings  206  configured to couple the accessory  200  to an attachment mechanism of an oscillating power tool, such as the attachment mechanism  10  of the oscillating power tool  12  described above or the other attachment mechanisms for oscillating power tools incorporated by reference and listed above. The openings  206  may include a generally U-shaped opening  208  extending from a rear end  210  of the accessory  200  and terminating in a central portion  209  centered at a center point about which the accessory  200  oscillates when coupled to the power tool  10 . A first set of three radial arm openings  212  are in communication with and extend radially outward from the central portion  208  at approximately 90°, approximately 180°, and approximately 270°, respectively, relative to the U-shaped opening  208 . A second set of six radial openings  214  are spaced radially outward from and not in communication with the central portion  209 , and are positioned at approximately 60°, approximately 120°, approximately 150°, approximately 210°, approximately 240°, and approximately 300° relative to the U-shaped opening  108 . This configuration enable the attachment portion to be coupled to a wide variety of brands of power tools. In other implementations, the attachment portion may have a configuration similar to those shown, e.g., in U.S. Pat. Nos. 10,245,716 and 10,265,778, which are incorporated by reference. In certain implementations, the attachment portion may be universal or nearly universal and/or may be coupleable to two or more the oscillating power tools described and incorporated by reference above. 
     The working portion  202  is coupled to the attachment portion  204  and extends generally along a longitudinal axis X. The working portion  202  has a body portion  203  bounded at least partially by a front cutting edge portion  222  with a plurality of teeth  228  opposite the rear end  210 , a first lateral non-cutting edge  224  extending from a first end of the front cutting edge  222  toward the rear end  210 , and a second lateral non-cutting edge  226  opposite the first lateral non-cutting edge  224  and extending from a second end of the front cutting edge  222  toward the rear end  210 . As illustrated, the body portion  203  has a generally hourglass shape. In other implementations, the body  203  may have other shapes or configurations such as rectangular, trapezoidal, sector shaped, semi-circular shaped, wedge shaped, etc. 
     As illustrated in  FIG. 2A , the front cutting edge portion  222  and its teeth  228  may be formed directly in the body  203 . As illustrated in  FIG. 2C , in another implementation, the front cutting edge portion  222  and its teeth  228  may be formed as a separate front cutting edge portion that is coupled to a front end of the body, e.g., by welding, brazing, adhesive, or other attachment mechanisms. Such a front cutting portion may be composed of a different material than the body  203 . For example, the body  203  may be composed of a first metal (e.g., low carbon steel and/or tool steel) and the front cutting edge portion  222  may be composed of a second, harder metal (e.g., a high speed steel, such as M42 steel or Matrix 2 steel, for a bi-metal accessory) or a hard metal compound (e.g., a carbide material for a carbide tooth accessory). 
     In an embodiment, the working portion  202  may have a rear end portion  220  that is connected to the attachment portion  204  by an intermediate portion  232 . In the implementation illustrated in  FIG. 2B , the working portion  202  and the attachment portion  204  may substantially lie (or may have portions that substantially lie) in parallel planes that are offset from one another by a height H (e.g., approximately 0.3 inches to approximately 0.6 inches). The intermediate portion  232  may be disposed at a right angle or an acute angle ϕ (e.g., approximately 15° to approximately 89°) to the attachment portion. This offset may make it easier for the blade  200  to be plunged deeper into a workpiece without interference from the clamp assembly  10  on the oscillating power tool  12 . In other implementations, the working portion  202  and the attachment portion  204  may be substantially co-planar (or have portions that are substantially co-planar) or may substantially lie (or have portions that substantially lie) in planes that are at an angle to one another. It will be understood to one of ordinary skill in the art that the working portion  202  and the attachment portion  204  may not be planar but instead may have portions that substantially lie in or along a plane or may be curved. 
     The teeth  228  on the front cutting edge  222  are asymmetrically arranged relative to the blade axis X. The cutting edge  222  is generally slanted at an acute angle α relative to the blade axis X. The cutting edge  222  includes a leading tooth  230  on one end of the cutting edge  222  located on one side of the axis X (e.g., at an intersection between the front cutting edge  222  and the first lateral edge  224 ) and a trailing tooth on an opposite end of the front cutting edge  222  located on an opposite side of the axis X (e.g., at an intersection between the front cutting edge  222  and the second lateral edge  226 ). The leading tooth  230  is disposed a first distance L 1  from the rear end  210  of the accessory and the trailing tooth  232  is disposed a second distance L 2  from the rear end  210  of the accessory that is less than the first distance. The first distance L 1  may be greater than or equal to a distance from all other teeth  228  to the rear end  210  of the accessory and the second distance L 2  may be less than or equal to a distance from all other teeth  228  to the rear end  210  of the accessory. The intermediate teeth  231  between the leading tooth  230  and the trailing tooth  232  each are disposed an intermediate distance L 3  from the rear end  210  of the accessory that is less than or equal to the first distance L 1  and greater than or equal to the second distance L 2 . The intermediate distances L 3  of the intermediate teeth  231  from the rear end  210  of the accessory may progressively decrease from the leading tooth  230  to the trailing tooth  232 . 
     In the embodiment illustrated in  FIGS. 2A-2C , the cutting edge  222  has a convex arc-shape pattern along a curve B that connects the tips of the teeth  228 . The curve B has a radius R that is centered at a center point Con one side of the axis X so that the front cutting edge  222  is asymmetrically arranged relative to the blade axis X. The center point C also may be disposed axially rearward of a center point P of the U-shaped opening  208  about which the accessory  200  oscillates when coupled to the tool  10 . Along the curved cutting edge  222  from the leading tooth  230  to the trailing tooth  232 , tangent lines T 1 , T 2 , T 3 , etc. to the curve B at points P 1 , P 2 , P 3 , etc. are disposed at an acute angles β 1 , β 2 , β 3 , etc. to a line Y that is perpendicular to the blade axis X, with the tangent angles β 1 , β 2 , β 3 , etc. progressively increasing from the leading tooth  230  to the trailing tooth  232  (e.g., from approximately 0° at the leading tooth  230  to approximately 15° at the trailing tooth  232 , with an average tangent angle β Cg  of approximately 3° to 10° (e.g., approximately 5°). In some embodiments the angle β 2  of one of the tangent lines T 2  to the line Y at a center tooth  233  is approximately 3° to 10° (e.g., approximately 5°)). In this way the line or curve B that connects the tips of the teeth  228  is slanted most or all of its entirety at an acute angle relative to the blade axis X. 
     The leading tooth  230  and the trailing tooth  232  may be at opposite ends of the cutting edge  222  or one or both may be disposed at intermediate locations along the cutting edge  222 . In the illustrated implementation, the teeth  228  each have the same size, form, shape, and spacing from adjacent teeth. In the illustrated implementation, each tooth  228  has a symmetrical triangular shape with rake faces joined at a cutting edge. In other implementations, the teeth  228  may have different and/or variable sizes, forms, shapes, and spacing. 
     As shown in  FIGS. 2D-2F , in operation, the slanted and curved front cutting edge  222  facilitates cutting wood workpieces W with nails N embedded therein. The slanted and curved front cutting edge  222  allows cutting to only occur when the blade is oscillating in one direction, and then allows the blade to clear any chips or debris when cutting in the opposite direction. As the blade oscillates in the counter-clockwise direction CCW (from the position in  FIG. 2D  to the position in  FIG. 2E  to the position in  FIG. 2F ), the teeth  228  on the cutting edge  222  dig into the workpiece to make a cut in the workpiece W and to cut through the nail N. As the blade oscillates in the opposite clockwise direction CW (from the position in  FIG. 2F  to the position in  FIG. 2E  to the position in  FIG. 2D ), the teeth  228  on the cutting edge  222  are generally disengaged from the cut made in the workpiece, the cutting edge facilitates clearance of chips and debris from the cut. This helps dissipate heat and prolong blade, tooth, and cutting edge life. 
     Referring to  FIGS. 3A-3B , in another implementation, an oscillating accessory  300  has a working portion  302 , an attachment portion  304  with a rear end  310 , and an intermediate portion  332  that are the same as the working portion  202 , attachment portion  204 , and intermediate portion  232  of the accessory  200 , except for the following differences. The working portion  302  has a slanted front cutting edge portion  322  with a plurality of teeth  328  that are arranged along a straight line B′ that is slanted at an acute angle θ (e.g., approximately 3° to approximately 10°, such as approximately 5°) relative to a line L that is perpendicular to the axis X so that the front cutting edge  322  is asymmetrically arranged relative to the axis X. The cutting edge portion  322  includes a leading tooth  330  on one side of the axis X (e.g., at an intersection between the front cutting edge  322  and the first lateral edge  324 ) and a trailing tooth  332  on an opposite side of the axis X (e.g., at an intersection between the front cutting edge  322  and the second lateral edge  324 ). The leading tooth  330  is disposed a first distance L 1 ′ from the rear end  310  of the accessory and the trailing tooth  332  is disposed a second distance L 2 ′ from the rear end  310  of the accessory that is less than the first distance. The first distance L 1 ′ may be greater than or equal to a distance from all other teeth  328  to the rear end  310  of the accessory and the second distance L 2 ′ may be less than or equal to a distance from all other teeth  328  to the rear end  310  of the accessory. 
     As illustrated in  FIG. 3A , the front cutting edge portion  322  and its teeth  328  may be formed directly in the body  303 . As illustrated in  FIG. 3B , in another implementation, the front cutting edge portion  322  and its teeth  328  may be formed as a separate front cutting edge portion that is coupled to a front end of the body, e.g., by welding, brazing, adhesive, or other attachment mechanisms. Such a front cutting portion may be composed of a different material than the body  303 . For example, the body  303  may be composed of a first metal (e.g., low carbon steel and/or tool steel) and the front cutting edge portion  322  may be composed of a second, harder metal (e.g., a high speed steel, such as M42 steel or Matrix 2 steel, for a bi-metal accessory) or a hard metal compound (e.g., a carbide material for a carbide tooth accessory). 
     The leading tooth  330  and the trailing tooth  332  may be at opposite ends of the cutting edge  322  or one or both may be disposed at intermediate locations along the cutting edge  322 . In the illustrated implementation, the teeth  328  each have the same size, form, shape, and spacing from adjacent teeth. In the illustrated implementation, each tooth  328  has a symmetrical triangular shape with rake faces joined at a cutting edge. In other implementations, the teeth  328  may have different and/or variable sizes, forms, shapes, and spacing. 
     As shown in  FIGS. 3C-3E , in operation, the slanted front cutting edge  322  facilitates cutting wood workpieces W with nails N embedded therein. The slanted front cutting edge  322  allows cutting to only occur when the blade is oscillating in one direction, and then allows the blade to clear any chips or debris when cutting in the opposite direction. As the blade oscillates in the counter-clockwise direction CCW (from the position in  FIG. 3C  to the position in  FIG. 3D  to the position in  FIG. 3E ), the teeth on the cutting edge dig into the workpiece to make a cut in the workpiece W and to cut through the nail N. As the blade oscillates in the opposite clockwise direction CW (from the position in  FIG. 3E  to the position in  FIG. 3D  to the position in  FIG. 3C ), the teeth on the cutting edge are generally disengaged from the cut made in the workpiece, the cutting edge facilitates clearance of chips and debris from the cut. This helps dissipate heat and prolong blade, tooth, and cutting edge life. 
     Oscillating saw blades having an asymmetric slanted cutting edge similar to the ones disclosed in  FIGS. 2A-2F and 3A-3E  have dramatically increased blade life than saw blades without such a cutting edge. For example, in an experiment, samples of an experimental oscillating cutting blade having a straight asymmetric slanted cutting edge at approximately 5°, a 0.023 inch blade thickness and teeth made of M42 steel were life tested cutting 1″ wide and 3″ tall nail embedded pine. They were compared to an existing blade having the same thickness and tooth material but a straight cutting edge (perpendicular to the blade axis). As shown in the below Table 1, the blade with the slanted cutting edge had an average life of 10.0 cuts until failure, while the blade having symmetric straight cutting edge (perpendicular to the blade axis) had an average life of 2.2 cuts until failure. This represents an approximately five-fold increase in blade life, which was far greater than expected. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Life cutting 1″ wide × 3″ tall nail embedded pine 
               
            
           
           
               
               
               
               
            
               
                   
                   
                 50° Slanted Cutting Edge 
                 Straight Cutting Edge 
               
               
                   
                   
                 0.023″ Blade Thickness 
                 0.023″ Blade Thickness 
               
               
                   
                 Sample 
                 M42 Steel Tooth Material 
                 M42 Steel Tooth Material 
               
               
                   
                   
               
            
           
           
               
               
               
               
            
               
                   
                 1 
                 9 
                 1 
               
               
                   
                 2 
                 7 
                 1 
               
               
                   
                 3 
                 14 
                 5 
               
               
                   
                 4 
                 10 
                 3 
               
               
                   
                 5 
                 8 
                 1 
               
               
                   
                 6 
                 12 
                 2 
               
               
                   
                 Avg: 
                 10.0 
                 2.2 
               
               
                   
                   
               
            
           
         
       
     
     In another sample experiment, three designs of oscillating cutting blades in accordance with the embodiment of  FIGS. 3A-3E  were life tested cutting 1″ wide and 3″ tall nail embedded pine. As shown in the below Table 2, the three designs had each had an asymmetric slanted cutting edge at approximately 5°. Design 1 had a blade thickness of 0.023″ and teeth made of M42 steel. Design 2 had a blade thickness of 0.031″ and teeth made of Matrix 2 steel. Design 3 had a blade thickness of 0.027″ and teeth made of Matrix 2 steel. These were compared to an existing Bosch OSL114F blade (which is marketed as the leader in blade life in cutting nail embedded wood) having a symmetric curved cutting edge, a blade thickness of 0.023″, and teeth made of Matrix 2 high speed steel and a DEWALT DWA4203 blade having a straight cutting edge (perpendicular to the blade axis), a 0.025″ blade thickness, and teeth made of M42 steel. As shown in Table 2, the experimental blades with Designs 1, 2, and 3 had an average life of 10.0, 7.6, and 7.8 cuts until failure, as compared to the Bosch blade having a life of 6.7 cuts until failure and the DEWALT blade having a life of 0.8 cuts until failure. This represents a much larger than expected increase in blade life. 
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 Life cutting 1″ wide × 3″ tall nail embedded pine 
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 Bosch OSL114F 
                 DEWALT DWA4203 
                 Design 1 
                 Design 2 
                 Design 3 
               
               
                   
                 Symmetric Curved 
                 Straight Cutting 
                 5° Slanted 
                 5° Slanted 
                 5° Slanted 
               
               
                   
                 Cutting Edge; 
                 Edge; 
                 Cutting Edge; 
                 Cutting Edge; 
                 Cutting Edge; 
               
               
                   
                 0.023″ thickness; 
                 0.025″ thickness; 
                 0.023″ thickness; 
                 0.031″ thickness; 
                 0.027″ thickness; 
               
               
                 Sample 
                 Matrix 2 teeth 
                 M42 teeth 
                 M42 steel teeth 
                 Matrix 2 teeth 
                 Matrix 2 teeth 
               
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                 1 
                 8 
                 0 
                 9 
                 7 
                 8 
               
               
                 2 
                 11 
                 1 
                 7 
                 3 
                 10 
               
               
                 3 
                 2 
                 1 
                 14 
                 9 
                 6 
               
               
                 4 
                 2 
                 2 
                 10 
                 10 
                 3 
               
               
                 5 
                 7 
                 0 
                 8 
                 9 
                 7 
               
               
                 6 
                 13 
                 1 
                 12 
                   
                 13 
               
               
                 7 
                 4 
                   
                   
                   
                   
               
               
                 Avg: 
                 6.7 
                 0.8 
                 10.0 
                 7.6 
                 7.8 
               
               
                   
               
            
           
         
       
     
     Even more unexpected, blades of the design of  FIGS. 3A-3E  have a faster cutting speed than the Bosch OSL114F blade. It is usually expected that the blade cutting speed will vary inversely to life so that as the life increases the cutting speed will decrease. This was especially true in this case because the blade with the slanted cutting edge cuts only when the blade is oscillating in one direction. However, unexpectedly, as shown in Table 3 below, the blade with the asymmetric slanted cutting edge has a faster cutting speed of 7.88 seconds per cut versus the Bosch OSL114 blade, which has a slower cutting speed of 8.40 seconds per cut. This represents an increase in cutting speed, which was contrary to expectations. 
     
       
         
           
               
             
               
                 TABLE 3 
               
             
            
               
                   
               
               
                 Cut time (seconds) in 1″ wide × 3″ tall nail embedded pine 
               
            
           
           
               
               
               
            
               
                   
                   
                 Bosch OSL114F 
               
               
                   
                 5° Slanted Cutting Edge; 
                 Symmetric Curved Cutting Edge; 
               
               
                   
                 0.023″ thickness; 
                 0.023″ thickness; 
               
               
                 Sample 
                 M42 steel teeth 
                 Matrix 2 teeth 
               
               
                   
               
            
           
           
               
               
               
            
               
                 1 
                 9.2 
                 7.6 
               
               
                 2 
                 8.0 
                 8.2 
               
               
                 3 
                 6.7 
                   
               
               
                 4 
                 8.9 
                   
               
               
                 5 
                 7.6 
                 8.9 
               
               
                 6 
                 6.9 
                 8.9 
               
               
                 Avg: 
                 7.88 
                 8.40 
               
               
                   
               
            
           
         
       
     
     Referring also to  FIGS. 4A-4B , in another implementation, an oscillating accessory  400  has a working portion  402 , an attachment portion  404  with a rear end  410 , and an intermediate portion  432  that are the same as the working portion  202 , attachment portion  204 , and intermediate portion  232  of the accessory  200 , except for the following differences. The working portion  402  has a front cutting edge  422  with a plurality of teeth  428  that are arranged along a straight line Y that is generally perpendicular to the axis X. The plurality of teeth includes a first subset of teeth  430  extending from the first lateral edge  424  toward the axis X, a second subset of teeth  432  extending from the second lateral edge  426  toward the axis X, and a third subset of teeth  434  disposed between the first subset of teeth  430  and the second subset of teeth  432  and intersecting the axis X. The first and second subsets of teeth  430 ,  432  have the same size, shape, configuration, and spacing, while the third subset of teeth  434  has a different size, shape, configuration, and/or spacing than the first and second subset of teeth  430 ,  432 . In the illustrated implementation, the first and second subsets of teeth  430 ,  432  are triangular with a coarse tooth pitch and the third subset of teeth  434  are triangular with a fine tooth pitch. The transition between the subsets may be gradual or sudden. 
     As illustrated in  FIG. 4A , the front cutting edge portion  422  and its teeth  428  may be formed directly in the body  402 . As illustrated in  FIG. 4B , in another implementation, the front cutting edge portion  422  and its teeth  428  may be formed as a separate front cutting edge portion that is coupled to a front end of the body  402 , e.g., by welding, brazing, adhesive, or other attachment mechanisms. Such a front cutting portion may be composed of a different material than the body  402 . For example, the body  402  may be composed of a first metal (e.g., low carbon steel and/or tool steel) and the front cutting edge portion  422  may be composed of a second, harder metal (e.g., a high speed steel, such as M42 steel or Matrix 2 steel, for a bi-metal accessory) or a hard metal compound (e.g., a carbide material for a carbide tooth accessory). 
     Referring also to  FIGS. 5A-5B , in another implementation, an oscillating accessory  500  has a working portion  502 , an attachment portion  504  with a rear end  510 , and an intermediate portion  532  that are the same as the working portion  202 , attachment portion  204 , and intermediate portion  232  of the accessory  200 , except for the following differences. The working portion  502  has a front cutting edge  522  with a plurality of teeth  528  that are arranged along a straight line Y that is generally perpendicular to the axis X. The plurality of teeth  528  alternate between a first tooth  530  and a second tooth  532  that are different from one another. In the illustrated implementation, the first and second teeth  530 ,  532  are mirror images of each other. The first tooth  530  is a triangular tooth having a first rake face  530   a  at a larger first rake angle θ 1  facing toward the first lateral edge  524  and a second rake face  530   b  at a smaller second rake angle θ 2  facing toward the second lateral edge  526 . The second tooth  532  is a triangular tooth having a third rake face  532   a  at a larger third rake angle θ 3  facing toward the second lateral edge  524  and a fourth rake face  532   b  at a smaller fourth rake angle θ 4  facing toward the second lateral edge  526 . In an implementation, the first and third rake angles θ 1 , θ 3  are the same and the second and fourth rake angles θ 2 , θ 4  are the same. The first and second teeth  530 ,  532  are separated by alternating first and second gullets  535 ,  536 . Each first gullet  534  is disposed between first and third rake faces  530   a ,  532   a  and have a larger first width W 1  and a larger first included angle α 1 . Each second gullet  536  is disposed between second and fourth rake faces  530   b ,  532   b  and have a smaller first width W 2  and a smaller first included angle α 2 . Thus, the teeth  528  alternate in pitch and spacing. In other implementations, the teeth  528  could have more than two sizes, shapes, configurations, and/or spacing of teeth, and/or may have alternating groups of teeth having similar sizes, shapes, configurations, and/or spacing within each group. 
     As illustrated in  FIG. 5A , the front cutting edge portion  522  and its teeth  528  may be formed directly in the body  502 . As illustrated in  FIG. 5B , in another implementation, the front cutting edge portion  522  and its teeth  528  may be formed as a separate front cutting edge portion that is coupled to a front end of the body  502 , e.g., by welding, brazing, adhesive, or other attachment mechanisms. Such a front cutting portion may be composed of a different material than the body  502 . For example, the body  502  may be composed of a first metal (e.g., low carbon steel and/or tool steel) and the front cutting edge portion  522  may be composed of a second, harder metal (e.g., a high speed steel, such as M42 steel or Matrix 2 steel, for a bi-metal accessory) or a hard metal compound (e.g., a carbide material for a carbide tooth accessory). 
     Referring also to  FIG. 5C , in another implementation, an oscillating accessory  500 ′ has a working portion  502 ′, an attachment portion  504  with a rear end  510 , and an intermediate portion that are the same as the working portion  502 , attachment portion  504 , and intermediate portion  532  of the accessory  500 , except for the following differences. The working portion  502 ′ has a front cutting edge  522 ′ with a plurality of teeth  528 ′ that alternate between a first tooth  530 ′ and a second tooth  532 ′ that are different from one another. The first tooth  530 ′ is a symmetrical triangular tooth having a first rake face  530   a ′ and a second rake face  530   b ′ each at a first rake angle θ 1 ′ relative to the axis X. The second tooth  532 ′ is a symmetrical triangular tooth having a third rake face  532   a ′ and a fourth rake face  532   b ′ each at a second rake angle θ 2 ′ relative to the axis X that is different (e.g., larger) than the first rake angle θ 1 ′. The first and second teeth  530 ′,  532 ′ are separated by alternating first and second gullets  535 ′,  536 ′ that are mirror images of one another and that each have the same included angle α′ and each having the same width W′. Thus, the teeth  528 ′ alternate in rake angle and size, while they are spaced at a constant spacing or pitch. In other implementations, the teeth  528 ′ could have more than two sizes, shapes, configurations, and/or spacing of teeth, and/or may have alternating groups of teeth having similar sizes, shapes, configurations, and/or spacing within each group. 
     Referring also to  FIGS. 6A-6B , in another implementation, an oscillating accessory  600  has a working portion  602 , an attachment portion  604  with a rear end  610 , and an intermediate portion  632  that are the same as the working portion  202 , attachment portion  204 , and intermediate portion  232  of the accessory  200 , except for the following differences. The working portion  602  has a front cutting edge  622  with a plurality of teeth  628  that are arranged along a straight line Y that is generally perpendicular to the axis X. The plurality of teeth  628  include a center tooth  630  having a symmetrical triangular shape aligned along the axis X, a first group of asymmetric teeth  632  arranged between the first lateral edge  624  and the center tooth  630  and a second group of asymmetric teeth  634  arranged between the second lateral edge  626  and the center tooth  630 . The first group of teeth  632  and the second group of teeth  634  are mirror images of one another. The center tooth  630  has rake faces  630   a ,  630   b  that define an included angle α between them. Each first and second tooth  632 ,  634  has a rake face  636  that is generally parallel to the axis X and a relief face  638  at a relief angle β to a line parallel to the cutting edge. Between each of the first teeth  632  and each of the second teeth  634  is a generally U-shaped gullet  640  having a height H. The tips of adjacent first and second teeth  632 ,  634  are spaced apart by a pitch distance P. In other implementations, the center tooth may comprise a plurality of center teeth that have the same sizes, shapes, configurations, and/or spacing, and/or the first teeth and the second teeth may be interspersed with one another. 
     As illustrated in  FIG. 6A , the front cutting edge portion  622  and its teeth  628  may be formed directly in the body  602 . As illustrated in  FIG. 6B , in another implementation, the front cutting edge portion  622  and its teeth  628  may be formed as a separate front cutting edge portion that is coupled to a front end of the body  602 , e.g., by welding, brazing, adhesive, or other attachment mechanisms. Such a front cutting portion may be composed of a different material than the body  602 . For example, the body  602  may be composed of a first metal (e.g., low carbon steel and/or tool steel) and the front cutting edge portion  622  may be composed of a second, harder metal (e.g., a high speed steel, such as M42 steel or Matrix 2 steel, for a bi-metal accessory) or a hard metal compound (e.g., a carbide material for a carbide tooth accessory). 
     Referring to  FIG. 7 , in another implementation, an oscillating accessory  700  has a working portion  702 , an attachment portion  704  with a rear end  710 , and an intermediate portion that are the same as the working portion  602 , attachment portion  604 , and intermediate portion  632  of the accessory  600 , except for the following differences. The working portion  702  has a front cutting edge  722  with a plurality of teeth  728  arranged along a straight line Y that is generally perpendicular to the axis X. The plurality of teeth  728  differ from the plurality of teeth  628  in that they include a plurality of (e.g., three) center teeth  730  each having a symmetrical triangular shape instead of a single center tooth  630 . The center teeth  730  are arranged symmetrically about the axis X. The plurality of teeth  728  also have a first group of asymmetric teeth  732  arranged between the first lateral edge  724  and the center teeth  730  and a second group of asymmetric teeth  734  arranged between the second lateral edge  726  and the center teeth  730 . The first and second groups of teeth  732 ,  734  are substantially the same as the teeth  632 ,  634  described above. 
     As shown in  FIG. 7 , the front cutting edge portion  722  and its teeth  728  may be formed as a separate front cutting edge portion that is coupled to a front end of the body  702 , e.g., by welding, brazing, adhesive, or other attachment mechanisms. Such a front cutting portion may be composed of a different material than the body  702 . For example, the body  702  may be composed of a first metal (e.g., low carbon steel and/or tool steel) and the front cutting edge portion  722  may be composed of a second, harder metal (e.g., a high speed steel, such as M42 steel or Matrix 2 steel, for a bi-metal accessory) or a hard metal compound (e.g., a carbide material for a carbide tooth accessory). In other embodiments, the front cutting edge portion and its teeth may be formed directly on the body and be composed of the same material as the body. 
     Referring to  FIG. 8 , in another implementation, an oscillating accessory  800  has a working portion  802 , an attachment portion  804  with a rear end  810 , and an intermediate portion that are the same as the working portion  602 , attachment portion  604 , and intermediate portion  632  of the accessory  600 , except for the following differences. The working portion  802  has a front cutting edge  822  with a plurality of teeth  828  arranged along a straight line Y that is generally perpendicular to the axis X. Like the teeth  628 , the plurality of teeth  828  include a center tooth teeth  830  having a symmetrical triangular shape centered on the axis X, a first group of asymmetric teeth  832  arranged between the first lateral edge  824  and the center teeth  830 , and a second group of asymmetric teeth  834  arranged between the second lateral edge  826  and the center teeth  830 . The first and second groups of teeth  832 ,  834  are substantially the same as the teeth  632 ,  634  described above except that they mirror images so that the rake faces face outward toward the lateral edges  824 ,  826  instead of inward to the axis X like the teeth  632 ,  634 . 
     As shown in  FIG. 8 , the front cutting edge portion  822  and its teeth  828  may be formed as a separate front cutting edge portion that is coupled to a front end of the body  802 , e.g., by welding, brazing, adhesive, or other attachment mechanisms. Such a front cutting portion may be composed of a different material than the body  802 . For example, the body  802  may be composed of a first metal (e.g., low carbon steel and/or tool steel) and the front cutting edge portion  822  may be composed of a second, harder metal (e.g., a high speed steel, such as M42 steel or Matrix 2 steel, for a bi-metal accessory) or a hard metal compound (e.g., a carbide material for a carbide tooth accessory). In other embodiments, the front cutting edge portion and its teeth may be formed directly on the body and be composed of the same material as the body. 
     Example implementations have been provided so that this disclosure will be thorough, and to fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of implementations of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example implementations may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example implementations, well-known processes, well-known device structures, and well-known technologies are not described in detail. 
     The terminology used herein is for the purpose of describing particular example implementations only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed. 
     When an element or layer is referred to as being “on,” “engaged to,” “connected to,” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to,” “directly connected to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
     Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example implementations. 
     Terms of degree such as “generally,” “substantially,” “approximately,” and “about” may be used herein when describing the relative positions, sizes, dimensions, or values of various elements, components, regions, layers and/or sections. These terms mean that such relative positions, sizes, dimensions, or values are within the defined range or comparison (e.g., equal or close to equal) with sufficient precision as would be understood by one of ordinary skill in the art in the context of the various elements, components, regions, layers and/or sections being described. 
     Numerous modifications may be made to the exemplary implementations described above. These and other implementations are within the scope of this application.