Tool manufacturing method

Abstract

A method for manufacturing hand tools, such as wrenches. The method generally includes the steps of providing a flat stock, cutting the flat stock into the desired two-dimension blank using a laser, and three-dimensionally machining the laser-cut 2D blank into the desired three-dimensional workpiece. The tool may undergo a heating treatment process and a surface treatment process. In the context of a wrench, the blank may be laser cut with a laser beam oriented to cut generally perpendicularly to the plane of the flat stock. After laser cutting, the handle and interface region between the handle and jaw(s) are machined to provide the desired three-dimensional shape. For example, the three-dimensional shape may be selected to provide a comfortable grip even when applying a high level of force. The wrench jaw may have an optimized geometry calculated so that there is no excess material or “over-designed” regions of the jaw. The wrench jaw has internal corners with optimized radii.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 
     
         1 . A method of manufacturing a wrench having a handle and at least one jaw, comprising the steps of:
 providing a flat stock, the flat stock having a thickness equal to a maximum thickness of the at least one jaw;   laser-cutting the flat stock to form a wrench blank, the wrench blank forming an unfinished handle portion and an unfinished jaw portion, the unfinished jaw portion extending from the unfinished handle portion, the unfinished handle portion and the unfinished jaw portion of the wrench blank having a uniform thickness equal to the thickness of the flat stock;   three-dimensionally machining the unfinished handle portion of the wrench blank to cut material from and reduce the maximum thickness of the unfinished handle portion of the wrench blank without reducing the maximum thickness of the unfinished jaw portion, thereby providing a three-dimensional workpiece with the unfinished handle portion having the desired three-dimensional shape and wherein the unfinished handle portion has a maximum thickness less than the maximum thickness of the unfinished jaw portion;   finishing the three-dimensional workpiece; and   heat treating the three-dimensional workpiece to arrive at the wrench, the at least one wrench jaw having a maximum thickness equal to the thickness of the flat stock and the wrench handle having a maximum thickness lesser than the thickness of the at least one wrench jaw.   
     
     
         2 . The method of  claim 1  wherein the at least one jaw includes a pair of spaced apart beams, each of the beams having a geometry with a height, h, in accordance with following the equation: 
       
         
           
             
               
                 h 
                 ⁡ 
                 
                   ( 
                   x 
                   ) 
                 
               
               = 
               
                 
                   
                     
                       6 
                       ⁢ 
                       F 
                     
                     
                       t 
                       ⁢ 
                       σ 
                     
                   
                   ⁢ 
                   x 
                 
               
             
           
         
       
       where F is a predetermined force, t is a thickness of the beam and σ is an allowable stress. 
     
     
         3 . The method of  claim 1  wherein the wrench is an angle wrench having at least one jaw and a handle, the at least one jaw being oriented at an angle to a longitudinal extent of the handle. 
     
     
         4 . The method of  claim 3  wherein the angle is at least 7.5 degrees. 
     
     
         5 . The method of  claim 1  wherein the at least one jaw includes a pair of beams spaced apart to define a wrench opening with a size, each of the beams having a flat hex engagement surface, each of the flat hex engagement surfaces joined to the remainder of the wrench at a separate internal corner, each internal corner having a radius of about one-third of the size of the wrench opening. 
     
     
         6 . The method of  claim 1  wherein the wrench jaw includes a pair of beams spaced apart to define a wrench opening with a size, each of the beams having a flat hex engagement surface, each of the flat hex engagement surfaces joined to the remainder of the wrench at a separate internal corner, each internal corner having a radius equal to the size of the wrench opening divided by C, where C is in the range of about 2.5 to 3.8. 
     
     
         7 . The method of  claim 1  wherein the laser-cutting step includes forming the at least one jaw portion at an offset from a longitudinal center of the handle, wherein the jaw portion includes a beam having a curved outer edge and the handle portion includes a linear longitudinal edge; and
 wherein the offset is selected such that the longitudinal edge of the handle portion is substantially tangent to the outer edge of the beam. 
 
     
     
         8 . The method of  claim 1  further including the step of bending at least one of the wrench blank or the three-dimensional workpiece to create an angle between the jaw and the handle of the wrench. 
     
     
         9 . The method of  claim 1  wherein the three-dimensional machining step includes three-dimensionally machining an interface region between the wrench handle and the wrench jaw. 
     
     
         10 . A method of manufacturing a wrench, comprising the steps of:
 providing a flat stock, the flat stock having a thickness equal to a maximum thickness of the wrench;   laser-cutting through the thickness of the flat stock to form the two-dimensional wrench blank having a wrench handle and at least one wrench jaw extending from the handle, the wrench blank being of uniform thickness equal to the thickness of the flat stock;   three-dimensionally machining at least a portion of the wrench handle to cut material from the maximum thickness of the wrench handle without cutting material from the maximum thickness of the at least one wrench jaw to provide a three-dimensional workpiece, the wrench handle of the three-dimensional workpiece having a three-dimensional shape and a maximum thickness less than the thickness of the flat stock and the maximum thickness of the at least one wrench jaw, the wrench jaw of the three-dimensional workpiece having a maximum thickness equal to the thickness of the flat stock; and   finishing the three-dimensional workpiece, the wrench handle of the finished three-dimensional workpiece having a maximum thickness less than a maximum thickness of the wrench jaw of the finished three-dimensional workpiece.   
     
     
         11 . The method of  claim 10  wherein said machining step is further defined as cutting material from a full length of the wrench handle to provide at least a portion of the wrench handle with a three-dimensional shape without removing material from the thickness of the wrench jaw. 
     
     
         12 . The method of  claim 11  wherein the wrench jaw includes a pair of spaced apart beams, each of the beams having a geometry with a height, h, in accordance with following the equation: 
       
         
           
             
               
                 h 
                 ⁡ 
                 
                   ( 
                   x 
                   ) 
                 
               
               = 
               
                 
                   
                     
                       6 
                       ⁢ 
                       F 
                     
                     
                       t 
                       ⁢ 
                       σ 
                     
                   
                   ⁢ 
                   x 
                 
               
             
           
         
       
       where F is a predetermined force, t is a thickness of the beam and σ is an allowable stress. 
     
     
         13 . The method of  claim 10  wherein the at least one wrench jaw includes a pair of beams spaced apart to define a wrench opening with a size, each of the beams having a flat hex engagement surface, each of the flat hex engagement surfaces joined to the remainder of the wrench at a separate corner, each internal corner having a radius equal to the size of the wrench opening divided by C, where C is in the range of about 2.5 to 3.8. 
     
     
         14 . The method of  claim 10  wherein the wrench is an angle wrench having the wrench jaw oriented at an angle of at least 7.5 degrees to a longitudinal extent of the wrench handle. 
     
     
         15 . The method of  claim 10  wherein the three-dimensional machining step includes three-dimensionally machining an interface region between the wrench handle and the wrench jaw. 
     
     
         16 . An angle-head wrench comprising:
 a wrench body having a handle and at least one jaw extending from the handle, the jaw extending at an angle to the longitudinal extent of the handle, the wrench body being laser cut from a flat stock having a thickness equal to a thickness of the jaw, the handle having at least one portion with a three-dimensional shape, the three-dimensional portion shaped from at least one machining operation cutting material from the thickness of the flat stock to reduce the maximum thickness of the handle lower than the maximum thickness of the jaw.   
     
     
         17 . The angle-head wrench of  claim 16  wherein the jaw includes a pair of spaced apart beams, each of the beams having a geometry with a height, h, in accordance with following the equation: 
       
         
           
             
               
                 h 
                 ⁡ 
                 
                   ( 
                   x 
                   ) 
                 
               
               = 
               
                 
                   
                     
                       6 
                       ⁢ 
                       F 
                     
                     
                       t 
                       ⁢ 
                       σ 
                     
                   
                   ⁢ 
                   x 
                 
               
             
           
         
       
       where F is a predetermined force, t is a thickness of the beam and σ is an allowable stress. 
     
     
         18 . The angle-head wrench of  claim 16  wherein the jaw includes a pair of beams each having a flat hex engagement surface, each of the flat hex engagement surfaces joined to the remainder of the wrench along a radius, the radius being maximized such that each flat hex engagement surface is at least approximately equal in length to a length of a surface of a hex head fastener of corresponding size. 
     
     
         19 . The angle-head wrench of  claim 16  wherein the jaw is oriented at an angle of at least 7.5 degrees to a longitudinal extent of the handle. 
     
     
         20 . The angle-head wrench of  claim 16  wherein the jaw includes a beam having a curved outer edge and the handle includes a linear longitudinal edge; and
 wherein the jaw is offset from the longitudinal center of the handle with the longitudinal edge of the handle being substantially tangent to the outer edge of the beam.