Patent Publication Number: US-2015061236-A1

Title: Soldered machining tool and soldered bar stock for forming the soldered machining tool

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a soldered machining tool that is used for milling, drilling, boring, or tapping thread, and also relates to a soldered bar stock that is used for forming the soldered machining tool. 
     2. Description of the Prior Art(s) 
     Heads of machining tools are formed into different shapes according to functions of the machining tools. For example, a machining tool with a pointed head is used to drill holes on a workpiece. In addition, a machining tool with a flat head is used to mill the workpiece or to tap threads in the holes of the workpiece. 
     A conventional machining tool has a clamping handle and a shank. The clamping handle may be made of stainless steel, carbon steel, or tungsten steel. The clamping handle has a recess formed in an end surface of the clamping handle. The shank may be made of tungsten steel and has a head formed on a front end of the shank. When assembling the shank to the clamping handle, the clamping handle is pre-heated to enlarge the recess of the clamping handle. Then a rear end of the shank is mounted into the recess of the clamping handle. As the clamping handle cools down, the recess of the clamping handle is reduced. Accordingly, the rear end of the shank is tightly fitted in the recess of the clamping handle. 
     In use, the clamping handle of the conventional machining tool is mounted in and clamped by a chuck of a processing machine, and the head of the shank is aimed at a workpiece. When the clamping handle as well as the shank is rotated with the chuck, the head of the shank mills the workpiece or drills holes on the workpiece. 
     However, when rotating in high speed and milling or drilling the workpiece, the conventional machining tool bears high torque. Since the shank is merely fitted tightly in the clamping handle, the shank breaks easily, especially at a connection junction where the shank and the clamping handle connect to each other. As the conventional machining tool wears and tears easily, qualities of milling or drilling with the conventional machining tool are low, and danger of using the conventional machining tool is high. 
     To overcome the shortcomings, the present invention provides a soldered machining tool and a soldered bar stock for forming the soldered machining tool to mitigate or obviate the aforementioned problems. 
     SUMMARY OF THE INVENTION 
     The main objective of the present invention is to provide a soldered machining tool and a soldered bar stock for forming the soldered machining tool. The soldered bar stock has a handle blank and a head blank. The handle blank has a first through hole axially formed through the handle blank. The head blank has a soldered portion protruding into the first through hole and is soldered to the handle blank. The soldered bar stock is machined to form the soldered machining tool. The soldered machining tool has a handle formed by machining the head blank, and has a head formed by machining the head blank. 
     With the first through hole formed in the handle blank, the head blank can be firmly soldered to the handle blank. When replacing the head blank with a new one, solder in the first through hole can be completely cleaned. Moreover, when using the soldered machining tool, a cooling liquid can be injected into the first through hole to cool down the soldered machining tool. 
     Other objectives, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded perspective view of a first embodiment of a soldered bar stock in accordance with the present invention; 
         FIG. 2  is a cross-sectional side view of the first embodiment of the bar stock in  FIG. 1 ; 
         FIG. 3  is an exploded perspective view of a first embodiment of a soldered machining tool in accordance with the present invention, wherein the first embodiment of the soldered machining tool is formed by machining the first embodiment of the bar stock in  FIG. 1 ; 
         FIG. 4  is a side view in partial section of the first embodiment of the soldered machining tool in  FIG. 3 ; 
         FIG. 5  is an exploded perspective view of a second embodiment of a soldered bar stock in accordance with the present invention; 
         FIG. 6  is a cross-sectional side view of the second embodiment of the bar stock in  FIG. 5 ; 
         FIG. 7  is a side view in partial section of a second embodiment of a soldered machining tool in accordance with the present invention; 
         FIG. 8  is an exploded perspective view of a third embodiment of a soldered bar stock in accordance with the present invention; 
         FIG. 9  is a cross-sectional side view of the third embodiment of the bar stock in  FIG. 8 ; 
         FIG. 10  is a side view in partial section of a third embodiment of a soldered machining tool in accordance with the present invention, wherein the third embodiment of the soldered machining tool is formed by machining the third embodiment of the bar stock in  FIG. 8 ; 
         FIG. 11  is an exploded perspective view of a fourth embodiment of a soldered bar stock in accordance with the present invention; 
         FIG. 12  is a cross-sectional side view of the fourth embodiment of the bar stock in  FIG. 11 ; and 
         FIG. 13  is a side view in partial section of a fourth embodiment of a soldered machining tool in accordance with the present invention, wherein the fourth embodiment of the soldered machining tool is formed by machining the fourth embodiment of the bar stock in  FIG. 11 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to  FIGS. 1 and 2 , a first preferred embodiment of a soldered bar stock  10  in accordance with the present invention comprises a handle blank  11 , a head blank  12 , and an end cap  13 . 
     The handle blank  11  is cylindrical, may be made of stainless steel, carbon steel, or tungsten steel, and has a front end surface, a rear end surface, and a first through hole  111 . The first through hole  111  is axially formed in the handle blank  11  and through the front end surface and the rear end surface of the handle blank  11 . Preferably, a diameter Rh of the first through hole  111  is one fourth to one half of a diameter R1 of the handle blank  11 . 
     The head blank  12  is securely mounted on the front end surface of the handle blank  11 , may be made of high hardness materials such as tungsten steel, polycrystalline diamond (PCD), cubic boron nitride (CBN), ceramic or the like, and has a pre-machining portion  122  and a soldered portion  121 . The pre-machining portion  122  is cylindrical and has a rear end surface. The rear end surface of the pre-machining portion  122  corresponds to the front end surface of the handle blank  11 . The soldered portion  121  is formed on and protrudes from the rear end surface of the pre-machining portion  122 , is mounted into the first through hole  111  of the handle blank  11 , and is soldered to the handle blank  11 . 
     The end cap  13  is mounted on the rear end surface of the handle blank  11  and has an end surface and a connecting protrusion  131 . The end surface of the end cap  13  corresponds to the rear end surface of the handle blank  11 . The connecting protrusion  131  is formed on and protrudes from the end surface of the end cap  13 , is mounted into the first through hole  111  of the handle blank  11 , and is tightly fitted in the handle blank  11 . 
     Specifically, the handle blank  11  and the pre-machining portion  122  are circular in cross-section. The first through hole  111  of the handle blank  11  is circular in cross-section. The soldered portion  121  of the head blank  12  and the connecting protrusion  131  of the end cap  13  correspond to the first through hole  111  of the handle blank  11  and are also circular in cross-section. Alternatively, the handle blank  11  and the pre-machining portion  122  may be polygonal in cross-section. The first through hole  111  of the handle blank  11  may be polygonal in cross-section. The soldered portion  121  of the head blank  12  and the connecting protrusion  131  of the end cap  13  correspond to the first through hole  111  of the handle blank  11  and may also be polygonal in cross-section. 
     The above-mentioned soldered bar stock  10  may be machined to form a soldered machining tool. A diameter of the soldered portion  121  of the head blank  12  and a proportion of a length of the handle blank  11  to a length of the head blank  12  are decided according to types of the soldered machining tool. The soldered machining tool may be a drill bit or a milling cutter. 
     With further reference to  FIGS. 3 and 4 , a first preferred embodiment of a soldered machining tool  20  in accordance with the present invention is formed by machining the above-mentioned first preferred embodiment of the soldered bar stock  10 . The first preferred embodiment of the soldered machining tool  20  comprises a handle  21 , a head  22  and the end cap  13 . 
     The handle  21  is formed by machining the handle blank  11  and has a clamping portion  211 , a shank  212 , multiple helical grooves  213 , a front end surface, and a rear end surface. The clamping portion  211  has a front end and a rear end. The shank  212  axially protrudes from the front end of the clamping portion  211  and has an outer surface and a distal end. The front end surface of the handle  21  is defined on the distal end of the shank  212 . The rear end surface of the handle  21  is defined on the rear end of the clamping portion  211 . A diameter of the shank  212  is shorter than a diameter of the clamping portion  211 . The helical grooves  213  of the handle  21  are formed on the outer surface of the shank  212 . The first through hole  111  is axially defined through the clamping portion  211  and the shank  212  of the handle  21 . 
     The head  22  is formed by machining the pre-machining portion  122  of the head blank  12 , is securely mounted on the front end surface of the handle  21 , is securely mounted on the distal end of the shank  212  of the handle  21 , and has a machining portion  221 , multiple helical grooves  222 , and the soldered portion  121 . The machining portion  221  has an outer surface and a rear end surface. The rear end surface of the machining portion  221  corresponds to the front end surface of the handle  21  and corresponds to the distal end of the shank  212  of the handle  21 . The helical grooves  222  of the head  22  are formed on the outer surface of the machining portion  221  and respectively communicate with the helical grooves  213  of the handle  21 . The soldered portion  121  of the head blank  12  is defined on the rear end surface of the machining portion  221  of the head  22 , is mounted into the first through hole  111  of the handle  21 , and is soldered to the handle  21 . 
     The end cap  13  is mounted on the rear end surface of the handle  21 , and is mounted on the rear end of the clamping portion  211  of the handle  21 . The connecting protrusion  131  of the end cap  13  is mounted into the first through hole  111  of the handle  21  and is tightly fitted in the handle  21 . 
     With reference to  FIGS. 5 and 6 , in a second preferred embodiment of a soldered bar stock  10 A in accordance with the present invention, a diameter R2 of the pre-machining portion  122 A of the head blank  12 A is different from the diameter R1 of the handle blank  11 A. Specifically, the diameter R2 of the head blank  12 A may be longer than the diameter R1 of the handle blank  11 A. 
     With reference to  FIG. 7 , in a second preferred embodiment of a soldered machining tool  20 A in accordance with the present invention, the head  22 A is elongated and has a length that approximates a length of the handle  21 A. 
     With reference to  FIGS. 8 and 9 , in a third preferred embodiment of a soldered bar stock  10 B in accordance with the present invention, the head blank  12 B has a uniform diameter. The diameter R2 of the pre-machining portion  122 B of the head blank  12 B is equal to a diameter Rs of the soldered portion  121 B of the head blank  12 B. 
     With further reference to  FIG. 10 , a third preferred embodiment of a soldered machining tool  20 B in accordance with the present invention is formed by machining the above-mentioned third preferred embodiment of the soldered bar stock  10 B. The pre-machining portion  122 B of the head blank  12 B of the soldered bar stock  10 B is machined to form the machining portion  221 B of the head  22 B of the soldered machining tool  20 B. An outer diameter R2′ of the machining portion  221 B is equal to the diameter Rs of the soldered portion  121 B of the head  22 B. Accordingly, the head  22 B has a uniform diameter. 
     With reference to  FIGS. 11 and 12 , in a fourth preferred embodiment of a soldered bar stock  10 C in accordance with the present invention, the head blank  12 C further has a second through hole  123 C. The second through hole  123 C is axially formed through the head blank  12 C. 
     With further reference to  FIG. 13 , a fourth preferred embodiment of a soldered machining tool  20 C in accordance with the present invention is formed by machining the above-mentioned fourth preferred embodiment of the soldered bar stock  10 C. The pre-machining portion  122 C of the head blank  12 C of the soldered bar stock  10 C is machined to form the machining portion  221 C of the head  22 C of the soldered machining tool  20 C. The second through hole  123 C is defined in the machining portion  221 C and the soldered portion  121 C of the head  22 C. 
     The soldered machining tool  20 ,  20 A,  20 B,  20 C and the soldered bar stock  10 ,  10 A,  10 B,  10 C for forming the soldered machining tool  20 ,  20 A,  20 B,  20 C as described have the following advantages. 
     When the soldered portion  121 ,  121 B,  121 C of the head blank  12 ,  12 A,  12 B,  12 C is inserted into the first through hole  111  of the handle blank  11 ,  11 A and is soldered to the handle blank  11 ,  11 A, air that exists in the first through hole  111  of the handle blank  11 ,  11 A is heated and expanded. The expanded air can be exhausted from the rear end surface of the handle blank  11 ,  11 A. Thus, the soldered portion  121 ,  121 B,  121 C of the head blank  12 ,  12 A,  12 B,  12 C and solder around the soldered portion  121 ,  121 B,  121 C will not be pushed out of the first through hole  111  by the expanded air. Accordingly, with the through hole  111  defined in the handle blank  11 ,  11 A, the soldered portion  121 ,  121 B,  121 C of the head blank  12 ,  12 A,  12 B,  12 C can be securely connected to the handle blank  11 ,  11 A. 
     Moreover, when the head  22 ,  22 A,  22 B,  22 C of the soldered machining tool  20 ,  20 A,  20 B,  20 C wears and breaks due to long term usage, the head  22 ,  22 A,  22 B,  22 C can be replaced with a new one. The end cap  13  is detached from the handle  21 ,  21 A first, and then a portion where the head  22 ,  22 A,  22 B,  22 C and the handle  21 ,  21 A connect to each other is heated. Accordingly, the solder between the head  22 ,  22 A,  22 B,  22 C and the handle  21 ,  21 A is melted. Then, a high-pressured fluid is injected into the first through hole  111  or a pin is inserted into the first through hole  111  from the rear end surface of the handle  21 ,  21 A to push the head  22 ,  22 A,  22 B,  22 C and the solder out of the first through hole  111 . Consequently, the soldered portion  121 ,  121 B,  121 C of the head  22 ,  22 A,  22 B,  22 C for replacement can be firmly soldered into the first through hole  111  of the handle  21 ,  21 A. 
     Furthermore, when using the first to third embodiments of the soldered machining tools  20 ,  20 A,  20 B as described, the end caps  13  can be detached from the handle  21 ,  21 A to allow a cooling liquid to be injected into the first through hole  111  from the rear end surface of the handle  21 ,  21 A. The cooling liquid flows out of the first through hole  111 , and flows along an outer surface of the handle  21 ,  21 A toward the head  22 ,  22 A,  22 B,  22 C. Thus, the cooling liquid cools down the head  22 ,  22 A,  22 B,  22 C that is heated by friction between the head  22 ,  22 A,  22 B,  22 C and a workpiece. Moreover, when using the fourth embodiment of the soldered machining tool  20 C, the cooling liquid further flows into and through the second through hole  123 C of the head  22 C to cool down the fourth embodiment of the machining tool  20 C. 
     Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and features of the invention, the disclosure is illustrative only. Changes may be made in the details, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.