Patent Publication Number: US-2021170502-A1

Title: Accessory tool

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 16/430,819, filed on Jun. 4, 2019, which is a continuation of U.S. patent application Ser. No. 15/373,623, filed Dec. 9, 2016, now U.S. Pat. No. 10,421,130, which claims priority to U.S. Provisional Patent Application No. 62/265,903, filed on Dec. 10, 2015, the entire contents of which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to accessory tools, and more particularly to accessory tool shanks. 
     SUMMARY OF THE INVENTION 
     The invention provides, in one aspect, an accessory tool including an effector end and a shank coupled to the effector end. The shank includes a tool engagement portion that is configured to be received within a tool and a reduced diameter portion disposed between the tool engagement portion and the effector end. The shank defines a first length, and the reduced diameter portion defines a second length that is 10% to 45% of the first length. 
     The invention provides, in another aspect, a method for manufacturing an accessory tool from a piece of stock metal. The method includes cutting a tool form from the stock metal. The tool form includes an effector end and a shank having a tool engagement portion. The shank has a first length. The method also includes removing material from a portion of the shank adjacent the effector end to form a reduced diameter portion between the tool engagement portion and the effector end. The reduced diameter portion defines a second length that is 10% to 45% of the first length. 
     The invention provides, in another aspect, a shank for an accessory tool. The shank includes a tool engagement portion that is configured to be received within a tool. The shank also includes a reduced diameter portion adjacent the tool engagement portion. The reduced diameter portion is configured to be coupled to an effector end of the accessory tool. The shank defines a first length, and the reduced diameter portion defines a second length that is 10% to 45% of the first length. 
     Other features and aspects of the invention will become apparent by consideration of the following detailed description and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of an accessory tool. 
         FIG. 2  is a bottom view of the accessory tool of  FIG. 1 . 
         FIG. 3  is a side view of a piece of stock metal. 
         FIG. 4  is a side view of a partially formed accessory tool. 
         FIG. 5  is a side view of an accessory tool according to another embodiment of the invention. 
         FIG. 6  is an end view of the accessory tool of  FIG. 5 . 
         FIG. 7  is another side view of the accessory tool of  FIG. 5 . 
         FIG. 8  is a side view of an accessory tool according to another embodiment of the invention. 
         FIG. 9  is an end view of the accessory tool of  FIG. 8 . 
         FIG. 10  is a side view of an accessory tool according to another embodiment of the invention. 
         FIG. 11  is an end view of the accessory tool of  FIG. 10 . 
     
    
    
     Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. 
     As used herein with reference to dimensions, the terms “approximately” and “about” mean within normal manufacturing tolerances of the product. Further, the term “approximately” with reference to other values means within a rounded numerical value. 
     DETAILED DESCRIPTION 
       FIGS. 1-11  illustrate accessory tools  20 ,  120 ,  220 ,  320  (e.g., a step drill bit  20  and socket adapters  120 ,  220 ,  320 ) that each include an effector end  24 ,  124 ,  224 ,  324  coupled to a shank  28 ,  128 ,  228 ,  328 . Each shank  28 ,  128 ,  228 ,  328  includes a tool engagement portion  32 ,  132 ,  232 ,  332  and a reduced diameter portion  36 ,  136 ,  236 ,  336 . As will be explained below, the reduced diameter portion  36 ,  136 ,  236 ,  336  removes localized regions of high stress and discontinuities, thereby increasing the durability of the shank  28 ,  128 ,  228 ,  328  to extend the operational lifetime of the accessory tools  20 ,  120 ,  220 ,  320 . 
     With reference to  FIGS. 1 and 2 , the effector end or step drill  24  includes a generally conically shaped body  40  having a series of stepped shoulders  44  that increase in diameter from a tip portion  48  to a base portion  52 , which includes a base shoulder  56 . At least one angled or spiral cut flute  60  ( FIG. 2 ) extends from the tip portion  48  to the base portion  52 . Cutting edges are defined at the intersections of the flute  60  and each shoulder  44 . 
     With continued reference to  FIG. 1 , the shank  28  is either permanently or removably coupled to the base portion  52  of the body  40  and extends a length L 1  measured from the base portion  52  to the end of the tool engagement portion  32 . The length L 1  is approximately 31.75 mm in the illustrated embodiment, but may be between about 20-40 mm in other embodiments. As noted above, the shank  28  includes the tool engagement portion  32  and the reduced diameter portion  36 . 
     The tool engagement portion  32  is configured to interface with a tool (e.g., power drill, hand tool, screw driver, etc.), and is disposed on an end of the shank  28  opposite the effector end  24 . The tool engagement portion  32  may have a hexagonal, circular, or other standard shaped cross section configured to be received by standard tool couplings (e.g., chuck, collet, etc.). In the illustrated example, the tool engagement portion  32  has a hexagonal cross section and has a first width W 1  ( FIG. 2 ) measured between a pair of opposed flat sides. In some embodiments, the first width W 1  is between approximately 6 to 8 mm. In further embodiments, the first width W 1  is about 6.35 mm. Additionally, the shank  28  includes a second width W 2  measured between a pair of opposed corners. In some embodiments, the second width W 2  is between approximately 6.5 to 8.5 mm. In further embodiments, the second width W 2  is about 7 mm. 
     With reference to  FIG. 1 , the reduced diameter portion  36  is disposed between the tool engagement portion  32  and the base shoulder  56 , and is substantially adjacent to and contiguous with the base shoulder  56 . In the illustrated embodiment, the reduced diameter portion  36  has a diameter D 1  of approximately 6 mm. In another embodiment, the reduced diameter portion  36  has a diameter D 1  between 4.5 mm and 6.2 mm. In yet another embodiment, the reduced diameter portion  36  has a diameter D 1  between approximately 5 mm and 6.1 mm. In yet another embodiment, the reduced diameter portion  36  has a diameter D 1  between approximately 5.5 mm and 6.1 mm. In yet another embodiment, the reduced diameter portion  36  has a diameter D 1  between approximately 5.8 mm and 6.1 mm. Alternatively, the diameter D 1  may be approximately between 70%-98% of the first width W 1 . More specifically, the diameter D 1  may be approximately between 85%-96% of the first width W 1 . Still more specifically, the diameter D 1  may be approximately between 90%-95% of the first width W 1 . 
     The reduced diameter portion  36  extends along a longitudinal length L 2  of the shank  28 . In the illustrated embodiment the longitudinal length L 2  is approximately 6 mm. In another embodiment, the longitudinal length L 2  may be less than approximately 25 mm. In another embodiment, the longitudinal length L 2  may be between approximately 4 mm and 8 mm. In yet another embodiment, the longitudinal length L 2  may be between approximately 5 mm and 7 mm. Alternatively, the longitudinal length L 2  may be between approximately 10% and 30% of the length of the shank  28 . More specifically, the longitudinal length L 2  may be between approximately 15% and 22% of the length L 1  of the shank  28 . Still more specifically, the longitudinal length L 2  may be between approximately 18% and 20% of the length L 1  of the shank  28 . Still more specifically, the longitudinal length L 2  may be approximately 19% of the length L 1  of the shank  28 . As another alternative, the longitudinal length L 2  may be between approximately 2.5% to 15% of an entire length of the accessory tool  20 . More specifically, the longitudinal length L 2  may be between approximately 5% and 10% of the entire length of the accessory tool  20 . Still more specifically, the longitudinal length L 2  may be between approximately 7% and 8% of the entire length of the accessory tool  20 . 
     The reduced diameter portion  36  further includes a fillet  64  on either end contiguous with the shank  28  and base shoulder  56 . In the illustrated embodiment, the fillets  64  have a radius of curvature RC 1  of approximately 4 mm. In another embodiment, the radius of curvature RC 1  may be between approximately 3 mm and 5 mm. In yet another embodiment, the radius of curvature RC 1  may be between approximately 3.25 mm and 4.75 mm. In yet another embodiment, the radius of curvature RC 1  may be between approximately 3.5 mm and 4.5 mm. 
     Still referring to  FIG. 1 , the shank  28  further includes a second reduced diameter portion  68  disposed between the reduced diameter portion  36  and the tool engagement portion  32 . The second reduced diameter portion  68  is configured to be engaged by a mechanism of a tool (e.g., a ball detent) to secure the shank  28  to the tool. The second reduced diameter portion  68  has a longitudinal length L 3  that is less than L 2  and a diameter D 2  that is substantially similar to D 1 , as shown in  FIG. 1 . In other embodiments, the second reduced diameter portion  68  may have dimensional characteristics L 3 , D 2 , and RC 2  that are substantially similar to, greater than, or less than L 2 , D 1 , and RC 2 , respectively. In other embodiments, the second reduced diameter portion  68  may be omitted. 
     In one embodiment, the shank  28  may be induction tempered in order to disperse stress risers in the shank  28  material, thereby increasing the toughness and decreasing the hardness of the shank  28 . By only treating the shank  28 , the body  40  of the step drill bit  20  remains hard and suitable for cutting a workpiece. 
     With reference to  FIGS. 3 and 4 , the step drill bit  20  described with respect to  FIGS. 1 and 2  may be manufactured from a piece of stock metal  72  ( FIG. 3 ) according to the following exemplary method. In a first step, the stock metal  72  of  FIG. 3  is cut into an initial step drill bit form  76  of  FIG. 4  using, for example, a lathe (e.g., single point cutting lathe). Either prior to, during, or after the first step, flat sections  80  are carved into the step drill bit form  76  at a location corresponding to the shank  28  in order to form the hexagonally shaped shank  28  and therefore the tool engagement portion  32  illustrated in  FIG. 1 . In a subsequent step, a portion of the shank  28  adjacent to the base shoulder  56  is cut or rounded into the reduced diameter portion  36  (e.g., by turning, grinding with an abrasive wheel, etc.). Additionally, in some embodiments, a second reduced diameter portion  68  may be formed in a similar fashion between the reduced diameter portion  36  and the tool engagement portion  32 . In some embodiments, the step drill bit  20  may be hardened (e.g., heat treated, coated, etc.) prior to forming the reduced diameter portion  36 . 
       FIGS. 5-7  illustrate another accessory tool. In this embodiment of the invention, the accessory tool is a socket adapter  120  that includes an effector end or adapter end  124  and a shank  128  having a tool engagement portion  132 , a first reduced diameter portion  136 , and a second reduced diameter portion  168 . The shank  128  of this embodiment illustrated in  FIGS. 5-7  is similar to the shank  128  described above with reference to  FIGS. 1-4 . The following description will focus on the differences between the socket adapter  120  and step drill bit  20  described above. 
     With continued reference to  FIGS. 5-7 , the socket adapter  120  includes the adapter end  124  having a body portion  126  and a base portion  130  contiguous with the shank  128  and delimiting the adapter end  124 . The body portion  126  has a cylindrical section  134  extending away from the base portion  130  that has four rounded protrusions  138  extending a distance H radially outward from an outer extent of the cylindrical section  134 . The body portion  126  has a width E measured from an outer portion of a first protrusion  138  to the outer portion of an adjacent protrusion  138 . The body portion  126  further includes an engagement mechanism in the form of at least one spring loaded ball detent  142  having a diameter F that is configured to engage corresponding features of a socket such that the socket may be detachably coupled to the socket adapter  120 . However, it should be noted that this engagement mechanism is merely exemplary. Other engagement mechanisms known in the art may be used in place of the ball detent  142  illustrated in  FIGS. 5-7 . 
     As illustrated in  FIG. 5 , the socket adapter  120  has a total length L of approximately 50 mm (i.e., 2 inches). However, the length L may be between approximately 40 mm and 60 mm in other embodiments. In another embodiments, the length L may be up to approximately 152.4 mm (i.e., 6 inches). In yet another embodiment, the length L may be up to approximately 76.2 mm (i.e., 3 inches). The adapter end  124  has a longitudinal length A of approximately 7.5 mm, 11 mm, or 15 mm. However, in other embodiments, the length A maybe between approximately 5 mm to 17.5 mm. The ball detent  142  is located at a distance B measured from a distal end of the adapter end  124 , where B is approximately 3 mm to 8 mm, or alternatively approximately 35% and 65% of the length A. 
     Still referring to  FIG. 5 , the base portion  130  of the adapter end  124  includes a wide base shoulder  146  having a diameter G and including a first fillet  150  that is continuous with the body portion  126  and a second fillet  154  that is continuous with the shank  128  to define an angle C with the shank. In some embodiments, the angle C is approximately 110°-140°. The shank  128  includes the tool engagement portion  132 , the first reduced diameter portion  136 , and the second reduced diameter portion  168 . Together, the tool engagement portion  132  and the second reduced diameter portion  168  define a length D. In some embodiments, the length D is approximately 18 mm to 25 mm. In general, the shank  128  may have other dimensional characteristics similar to dimensional characteristics described above with respect to the shank of  FIGS. 1-4 . That is, the first reduced diameter portion  136  may have dimensional characteristics similar to those described above with reference to the first reduced diameter portion  36 , the second reduced diameter portion  168  may have dimensional characteristics similar to those described above with reference to the second reduced diameter portion  68 , the tool engagement portion  132  may have dimensional characteristics similar to those described above with reference to the tool engagement portion  32 , etc. 
     As seen in Table 1 below, the socket adapter  120  of  FIGS. 5-7  may be constructed in at least three sizes (e.g., ¼ inch, ⅜ inch, ½ inch, etc.). Examples of dimensional characteristics for the dimensions A-H described above with reference to  FIGS. 5-6  are provided below. It should be noted that each dimension listed below may vary by approximately +/−30%. 
     
       
         
           
               
               
               
               
               
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                   
                 “A” 
                 “B” 
                 “C” 
                 “D” 
                 “E” 
                 “F” 
                 “G” 
                 “H” 
               
               
                 PART NAME 
                 (mm) 
                 (mm) 
                 (mm) 
                 (mm) 
                 (mm) 
                 (mm) 
                 (mm) 
                 (mm) 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 SOCKET 
                 7.5 
                 3.5 
                 N/A 
                 23.80 
                 6.25-6.35 
                 3.18 
                 7.9-8.4 
                 1.0 
               
               
                 ADAPTER, ¼″ 
               
               
                 SOCKET 
                 11.0 
                 5.5 
                 125.0 
                 23.80 
                 9.42-9.53 
                 4.78 
                 12.0-12.7 
                 2.5 
               
               
                 ADAPTER, ⅜″ 
               
               
                 SOCKET 
                 15.0 
                 7.5 
                 125.0 
                 19.30 
                 12.59-12.70 
                 6.35 
                 15.6-16.8 
                 3.0 
               
               
                 ADAPTER, ½″ 
               
               
                   
               
            
           
         
       
     
     In addition, the shank  128  of the socket adapter  120  may be formed using a similar process to the method described above with respect to  FIGS. 1-4 . 
       FIGS. 8-9  illustrate yet another accessory tool. In this embodiment of the invention, the accessory tool is another socket adapter  220  that includes an effector end or adapter end  224  and a shank  228  having a tool engagement portion  232  and a first reduced diameter portion  236 . The shank  228  of the embodiment illustrated in  FIGS. 8-9  is similar to the shank  128  described above with reference to  FIGS. 5-7 , but with the second reduced diameter portion  168  omitted. Accordingly, similar parts will be labeled with the same reference numeral plus “100.” Additionally, labeled dimensions A-H refer to the same dimensions as those described above with reference to  FIGS. 5-7 . As seen in Table 2 below, the socket adapter  220  of  FIGS. 8-9  may be constructed in at least two sizes (e.g., ¼ inch, ⅜ inch, etc.). Examples of dimensional characteristics for the dimensions A-G described above are provided below. It should be noted that each dimension listed below may vary by approximately +/−30%. 
     
       
         
           
               
               
               
               
               
               
               
               
               
             
               
                 TABLE 2 
               
               
                   
               
               
                   
                 “A” 
                 “B” 
                 “C” 
                 “D” 
                 “E” 
                 “F” 
                 “G” 
                 “H” 
               
               
                 PART NAME 
                 (mm) 
                 (mm) 
                 (mm) 
                 (mm) 
                 (mm) 
                 (mm) 
                 (mm) 
                 (mm) 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 SOCKET 
                 7.5 
                 3.5 
                 N/A 
                 11.80 
                 6.25-6.35 
                 3.18 
                 7.9-8.4 
                 3.0 
               
               
                 ADAPTER, ¼″ 
               
               
                 SOCKET 
                 11.0 
                 5.5 
                 125.0 
                 11.80 
                 6.42-9.53 
                 4.78 
                 12.0-12.7 
                 1.0 
               
               
                 ADAPTER, ⅜″ 
               
               
                   
               
            
           
         
       
     
     In addition, the shank  228  of the socket adapter  220  may be formed using a similar process to the method described above with respect to  FIGS. 1-4 . 
       FIGS. 10-11  illustrate yet another accessory tool. In this embodiment of the invention, the accessory tool is another socket adapter  320  that includes an effector end or adapter end  324  and a shank  328  having a tool engagement portion  332  and a first reduced diameter portion  336 . The shank  328  of the embodiment illustrated in  FIGS. 10-11  is similar to the shank  128  described above with reference to  FIGS. 5-7 , but with the second reduced diameter portion  168  omitted. Accordingly, similar parts with be labeled with the same reference numeral plus “200.” Additionally, labeled dimensions A-H refer to the same dimensions as those described above with reference to  FIGS. 5-7 . As seen in Table 3 below, the socket adapter  320  of  FIGS. 10-11  may be constructed in at least one size (e.g., ½ inch, etc.). Examples of dimensional characteristics for the dimensions A-G described above are provided below. It should be noted that each dimension listed below may vary by approximately +/−30%. 
     
       
         
           
               
               
               
               
               
               
               
               
               
             
               
                 TABLE 3 
               
               
                   
               
               
                   
                 “A” 
                 “B” 
                 “C” 
                 “D” 
                 “E” 
                 “F” 
                 “G” 
                 “H” 
               
               
                 PART NAME 
                 (mm) 
                 (mm) 
                 (mm) 
                 (mm) 
                 (mm) 
                 (mm) 
                 (mm) 
                 (mm) 
               
               
                   
               
             
            
               
                 SOCKET 
                 15.0 
                 7.5 
                 125.0 
                 7.60 
                 12.59-12.70 
                 6.35 
                 7.9-8.4 
                 3.0 
               
               
                 ADAPTER, ½″ 
               
               
                   
               
            
           
         
       
     
     In addition, the shank  328  of the socket adapter  320  may be formed using a similar process to the method described above with respect to  FIGS. 1-4 . 
     The accessory tools  20 ,  120 ,  220 ,  320  each include shanks  28 ,  128 ,  228 ,  328  with tool engagement portions  32 ,  132 ,  232 ,  332  and reduced diameter portions  36 ,  136 ,  236 ,  336 . As described above, the reduced diameter portions  36 ,  136 ,  236 ,  336  have diameters between approximately 4.5 mm and 6.2 mm and lengths between approximately 4 mm to 8 mm. In specific embodiments, the reduced diameter portions  36 ,  136 ,  236 ,  336  have a diameter and length of approximately 6 mm. In addition, the length of the reduced diameter portions  36 ,  136 ,  236 ,  336  are approximately 10-45% the length of the shanks  28 ,  128 ,  228 ,  328 . 
     In operation of the accessory tool  20 ,  120 ,  220 ,  320 , the reduced diameter portion  36 ,  136 ,  236 ,  336  of the shank  28 ,  128 ,  228 ,  328  is configured to increase the impact resistance or the toughness of the accessory tool  20 ,  120 ,  220 ,  320 , such that the effector end  24 ,  124 ,  224 ,  324  of the accessory tool  20 ,  120 ,  220 ,  320  is allowed to elastically deform or twist relative to the shank  28 ,  128 ,  228 ,  328  about a central axis  22  of the accessory tool  20 ,  120 ,  220 ,  320 . Specifically, the polar moment of inertia of the shank  28 ,  128 ,  228 ,  328  is decreased by incorporating the reduced diameter portion  36 ,  136 ,  236 ,  336 , thereby reducing the amount of torsion required to elastically twist the shank  28 ,  128 ,  228 ,  328 , compared to a configuration of the shank  28 ,  128 ,  228 ,  328  having a cylindrical shape (i.e., without the reduced diameter portion  36 ,  136 ,  236 ,  336 ). 
     Conventional accessory tools are known to break along certain portions of the shank. More specifically, they are known to break generally along the area in which the reduced diameter portion  36  and second reduced diameter portions have been added. Advantageously, the shank  28 ,  128 ,  228 ,  328  of the invention provides at least one reduced diameter portion  36 ,  136 ,  236 ,  336  having an area of consistent, low variation surface finish. In addition, stress risers are removed from this area of the shank (e.g., by induction tempering, etc.). The reduced diameter portion  36 ,  136 ,  236 ,  336  also provides additional flexibility relative to a shorter such section, which may be beneficial for improved life for an accessory tool  20 ,  120 ,  220 ,  320 . 
     Although the invention has been described in detail with reference to certain preferred embodiments, variations and modifications exist within the scope and spirit of one or more independent aspects of the invention as described. Various features of the invention are set forth in the following claims.