Abstract:
An apparatus for changing cutting tool bits rapidly on milling machines, lathes, drills and other types of rotary power tools includes a first portion that is attached to the rotary power tool and retained thereto. A second portion includes the tool bit attached thereto. The second portion is inserted longitudinally toward the rotary power tool and into a bottom of the first portion after a slide has also first been longitudinally displaced in a direction toward the rotary power tool. A plurality of balls are displaced outward, the balls preferably being ball bearings, thereby permitting an upper conical taper of the second portion to bear against an inside taper of the first portion. The slide is released and urged by an inner spring in an opposite direction forcing the balls to engage with an upper edge of a circular recess provided in the second portion, thereby retaining the second portion in position. Tangs and corresponding recesses cooperate to supply torque that is applied by the rotary tool to the first portion to the second portion and to the tool bit.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention, in general, relates to milling machines and lathes and, more particularly, to a quick-release tool holder for rapidly changing tool bits and cutters. 
   Those skilled in the art of using milling machines and lathes know about changing tools. The terms “tool” or “tool bits” as used herein is intended to apply to any type of a rotary tool that actually contacts the work-piece and removes material from it. Drill, grinding, and cutting bits are included and are benefited by the instant invention. 
   The term, “rotary tools” is intended to include any tool that rotates the tool bit or work-piece and allows contact of the tool bit with the work-piece. Milling machines and lathes are examples of rotary tools. 
   It is often necessary to frequently change tool bits. This is time-consuming. It is also necessary for any device that expedites the process to securely hold the tool bit in a repeatable position; else inaccuracies and non-repeatability will occur. This is true for many numerically controlled (i.e., computer controlled) milling machines and other types of rotary machines (i.e., lathes, etc.) that are programmed to perform a repetitive operation on a plurality of work-pieces. 
   The tool bit must be centered by any tool holder. The tool holder must also be able to transmit a great deal of torque to the actual tool bit, as the tool bit contacts the work-piece. 
   These needs are true for a variety of rotary tools, including lathes and milling machines. A smaller class of milling machines experiences frequent tool bit changes and would especially benefit from such a device. 
   Accordingly, there exists today a need for a quick-release tool holder for rotary tools that helps ameliorate the afore-mentioned difficulties. 
   Clearly, such an apparatus would be a useful and desirable device. 
   2. Description of Prior Art 
   Tool holders are, in general, known. Prior art tool holders do not adequately center each successive tool bit. Some devices introduce an offset mass in the tool holder that causes vibration during rotation of the tool bit, or which may snag on an operator&#39;s clothing. Also, prior devices do not adequately remove slack and so the actual tool bit is not held with sufficient rigidity. 
   While the structural arrangements of the above described devices may, at first appearance, have similarities with the present invention, they differ in material respects. These differences, which will be described in more detail hereinafter, are essential for the effective use of the invention and which admit of the advantages that are not available with the prior devices. 
   OBJECTS AND SUMMARY OF THE INVENTION 
   It is an object of the present invention to provide a quick-release tool holder for rotary tools that is easy to use. 
   It is also an important object of the invention to provide a quick-release tool holder for rotary tools that is safe to use. 
   Another object of the invention is to provide a quick-release tool holder for rotary tools that permits quick changing of a tool bit. 
   Still another object of the invention is to provide a quick-release tool holder for rotary tools that automatically centers a tool bit in the rotary tool. 
   Still yet another object of the invention is to provide a quick-release tool holder for rotary tools that can transmit as much torque as is desired to a tool bit. 
   Yet another important object of the invention is to provide a quick-release tool holder for rotary tools that includes a tang for transmitting torque from a first half of the tool holder to a second half of the tool holder. 
   Still yet another important object of the invention is to provide a quick-release tool holder for rotary tools that includes a longitudinal motion of a portion of a first portion of a tool holder in a first direction to release a second portion of the tool holder apart from the first portion of the tool holder. 
   A first continuing object of the invention is to provide a quick-release tool holder for rotary tools that includes a longitudinal motion of a portion of a first portion of a tool holder in a second direction to permit insertion of a second portion of the tool holder into the first portion of the tool holder. 
   A second continuing object of the invention is to provide a quick-release tool holder for rotary tools that includes a longitudinal motion of a portion of a first portion of a tool holder in a second direction to permit insertion of a second portion of the tool holder into the first portion of the tool holder and which includes a longitudinal motion of the portion of the first part in a first direction to secure the second portion of the tool holder to the first portion of the tool holder. 
   A third continuing object of the invention is to provide a quick-release tool holder for rotary tools that automatically centers a second portion of a tool holder with respect to a first portion and which automatically takes up slack between the two. 
   Briefly, a quick-release tool holder for rotary tools that is constructed in accordance with the principles of the present invention has a first portion of the tool holder that includes an assembly that is attached to the rotary tool. The first portion includes a slide that moves a predetermined distance along a longitudinal length of the tool holder in a first direction sufficient to permit release of a second portion of the tool holder apart from the first portion. Alternately, to insert the second portion of the tool holder into the first portion, the slide is also moved in the first direction a sufficient amount to permit insertion of the second portion into the first part. A pair of tangs disposed on either the first or on the second portion engages with a pair of recesses in the opposite portion and is used to transmit torque from the first portion to the second portion. The slide is then urged in an opposite second direction during which the second portion is secured to the first portion, centered, and any slack between the two is automatically removed a sufficient amount. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an exploded view, in perspective, of a normal drive type of a quick-release tool holder for rotary tools. 
       FIG. 2  is a side view of the normal drive type of a quick-release tool holder of  FIG. 1  with a first portion and a second portion in a spaced-apart relationship. 
       FIG. 3  is a cross sectional view of the normal drive type of a quick-release tool holder of  FIG. 2  taken along the line  3 - 3  of  FIG. 2 . 
       FIG. 4  is a side view of the normal drive type of a quick-release tool holder of  FIG. 1  with a first portion engaged with a second portion. 
       FIG. 5  is a cross sectional view of the normal drive type of a quick-release tool holder of  FIG. 4  taken along the line  5 - 5  of  FIG. 4 . 
       FIG. 6  is a side view of a modified drive type of a quick-release tool holder. 
       FIG. 7  is a cross-sectional view along a longitudinal length of a master of a first portion of a quick release tool holder of  FIG. 1 . 
       FIG. 8  is a view in perspective of a first portion of a quick release tool holder of  FIG. 1 . 
       FIG. 9  is a cross-sectional view along the line B-B of the first portion of a quick release tool holder of  FIG. 10 . 
       FIG. 10  is a side view of a first portion of a quick release tool holder of  FIG. 1 . 
       FIG. 11  is a cross-sectional view taken along the line A-A of  FIG. 14  of a slide of a first portion of a quick release tool holder of  FIG. 1 . 
       FIG. 12  is a view in perspective of a slide of a first portion of a quick release tool holder of  FIG. 1 . 
       FIG. 13  is an end view of the slide of the first portion of a quick release tool holder of  FIG. 14 . 
       FIG. 14  is a side view of a slide of a first portion of a quick release tool holder of  FIG. 1 . 
       FIG. 15  is a side view taken of a second portion of a quick release tool holder of  FIG. 1 . 
       FIG. 16  is a view in perspective of a second portion of a quick release tool holder of  FIG. 1 . 
       FIG. 17  is a view in perspective of a D-shaped end of a tool bit for attachment to a second portion of a quick release tool holder of  FIG. 1 . 
       FIG. 18  is a cross-sectional view taken along the line A-A of  FIG. 15  of a second portion of a quick release tool holder of  FIG. 1 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to all of the drawings and appendices on occasion, and now in particular to  FIG. 1  is shown, a quick-release tool holder for rotary tools, identified in general by the reference numeral  10 . 
   The tool holder  10  includes a first portion, identified in general by the reference numeral  12  and a detachable second portion, identified in general by the reference numeral  14 . 
   The first portion  12  is an assembly that includes a master  16 , spring  18 , slide  20 , and a plurality of balls  22 . 
   The second portion  14  is intended to secure a tool bit  24  thereto, the tool bit  24  shown in dashed lines. The tool bit  24  includes any type of size of cutting tool or end mill, etc., as is desired. The tool bit  24  is attached by a set screw  15  ( FIG. 3 ) that passes through a threaded opening provided in the second portion  14  and bears against the tool bit  24 . Normally, the tool bit  24  includes a flat side that the set screw  15  bears against. 
   The tool bit  24  is inserted fully into a corresponding opening  25  that is provided at a first end  14   a  of the second portion  14 . The corresponding opening  25  includes a shape, preferably, that matches that of an upper end of the tool bit  24 , in cross-section. Normally, this shape includes a “D-shape” cross-section, as is well known in the tool bit  24  arts. 
   The corresponding opening  25  terminates at a top thereof inside the second portion at a smaller diameter second opening  25   a  that extends all the way through the second portion  14 . Accordingly, a longitudinal length of the second portion  14  is open from the first end  14   a  of the second portion  14  to an opposite second end  14   b  thereof. 
   This provides certain benefits that permit easier insertion or removal of the tool bit  24  there-from, for example, not increasing air pressure in the corresponding opening  25  that would make full insertion of the tool bit  24  therein difficult to accomplish. 
   If desired, the tool bit  24  can be secured to the second portion by any preferred method, for example by a threaded-type of attachment, adhesive, welding, or by any other preferred method. The second portion  14  can be sold with or without the tool bit  24  attached thereto. 
   Referring now also to the remaining drawing figures, is shown the master  16 , which includes inside threads  26  disposed at a first end  16   a  thereof. The inside threads  26  are for direct attachment of the master  16  to a rotary tool, not shown, in a well-known way. The rotary tool includes any preferred type of drill, lathe, or milling machine. Once attached to the rotary tool, the master  16  is not normally changed or removed. 
   The master  16  includes a larger outside diameter upper portion  28  and a smaller outside diameter lower portion  30 . The smaller inside portion includes three equally spaced openings  32  that are disposed the same distance from the first end  16   a.    
   Each of the openings  32  includes a larger inside diameter upper portion and a smaller diameter inside lower lip  32   a . The larger diameter upper portion of the opening  32  permits a corresponding one of the balls  22  to pass freely into and along a longitudinal length of the opening  32  from the outside of the master  16 , but to not pass all the way through the opening  32 . The lower lip  32   a  retains the ball  22  and prevents it from passing through the master  16  and being lost when the second portion  14  is absent from the first portion  12 . 
   An odd number of balls  22  and openings  32  with three of each being the minimum are preferred to automatically center the second portion  14 , when it is engaged, inside of the first portion  12 . 
   A retaining ring  34  fits into a circular recess in the master  16  proximate the first end  16   a  thereof. 
   The slide  20  includes a plurality of outer bands  36  that increase friction and allow it to be securely grasped and urged in a first direction, as shown by arrow  37  ( FIG. 3 ). Of course, other methods to increase friction may be used or, if preferred, no additional method of increasing friction need be included. 
   Referring still to  FIG. 3 , a cross-sectional view, the slide  20  includes an inside conical taper  38  with a smaller diameter thereof disposed closer toward the first end of the master  16 , when the slide  20  is assembled thereto. 
   To assemble the tool holder  10 , the spring  18 , which is a coil spring, is disposed over the lower portion  30  of the master  16 . The slide  20  is then urged over the lower portion  30  in the direction of arrow  37  until the spring  18  is fully compressed against a ridge  30  of the master  16 . 
   One each of the balls  22  is then placed in each of the openings  32 . The slide  20  is then released and is urged in a direction opposite that as shown by arrow  37  by the spring  18 . The taper  38  urges each ball  22  fully down into the opening  32  until it is stopped by the lower lip  32   a . This, in turn, stops further movement by the slide  20  in the direction that is opposite that as shown by arrow  37 . 
   The slide  20 , spring  18 , and balls  22  are retained in position as an assembly that can only be disassembled if the slide  20  is urged sufficiently far in the direction as shown by arrow  37  to permit removal of the balls  22  from the openings  32 . To prevent this from happening, the retaining ring  34  is secured to the master  16 .  FIG. 2  and  FIG. 3  show how the retaining ring  34  limits movement of the slide  20  in the direction as shown by arrow  37 . 
   Using the threads  26 , the master  16  is then threaded onto a driven rotating member of the rotary tool (not shown) that rotates the master  16  when the rotary tool is turned on. Obviously, a work-piece (not shown) is disposed proximate the tool bit  24  and is secured in position to the rotary tool as is well known in the machine arts. 
   The master  16  includes a pair of tangs  40  that extend away from the first end  16   a . The tangs  40  are intended to engage with corresponding recesses  42  in the second portion  14  and are used to supply torque to the second portion  14 . As many or as few of the tangs  40  and the recesses  42 , as desired, are included. Certain versions of the tool holder  10  will handle larger or smaller tool bits  24  and will therefore experience a range of torque forces. The tangs  40  and recesses  42  allow for easy design flexibility in this regard. 
   To quickly insert the second portion  14  and tool bit  24  into the master  16 , the slide  20  is urged along a longitudinal axis of the master  16  in the direction of arrow  37  as far as it can go until it contacts the retainer ring  34 . The second end  14   b  of the second portion  14  is then inserted into an opening at an opposite second end  16   b  of the master  16  along a center longitudinal axis of the master  16  as far as it will go toward the threads  26 . An upper conical taper  45  of the second portion  14  that is proximate the second end  14   b  thereof, urges the balls  22  outward toward the slide  20  sufficient to permit the second portion  14  to fully enter into the master  16 . 
   The upper conical taper  45  of the second portion  14  is carefully machined to match that of an inside taper  47  of the master  16 . The second portion  14  is inserted into the master  16  until the upper conical taper  45  bears against the inside taper  47 . 
   Referring now also to  FIG. 4  and to  FIG. 5 , the slide  20  is then released while continuing to retain the second portion  14  in a fully inserted position, up and fully in contact with the master  16 . The spring  18  then urges the slide  20  toward the second end  16   b  of the master  16  which forces the balls  22  to enter into the openings  32  until the balls  22 , which are forced inward by the inside conical taper  38  of the master  16 , contact an upper edge  44  of a circular recess  46  that is provided around an outer circumference of the second portion  14 . 
   Because the balls  22  bear against the upper edge  44 , they exert a force that retains the upper conical taper  45  of the second portion  14  in direct contact with the inside taper  47 . This removes slack between the first portion  12  and the second portion  14 . 
   Accordingly, different second portions (not shown) that include various different tool bits (not shown) can be substituted for the second portion  14  (and for the tool bit  24 ) while ensuring that a center longitudinal axis of each different tool bit will be in alignment with that of the tool bit  24  and that of the second portion  14  and that of the first portion  12 . 
   Where it not for the tangs  40  and recesses  42 , the second portion  14  could rotate about its center longitudinal axis with respect to the first portion  12 . However, when the second portion  14  is inserted into the first portion  12 , it is rotated about its center longitudinal axis an amount sufficient to ensure that the tangs  40  enter into the recesses  42 . 
   This alignment must be accomplished to secure the second portion  14  to the first portion  12 . Otherwise, the second portion  14  cannot be fully inserted into the first portion  12 . If the second portion  14  is not fully inserted into the first portion  12  it is impossible for the balls  22  to engage in (i.e., enter) the circular recess  46 . 
   Instead, the balls  22  will bear against a portion of the upper conical taper  45  which in turn, will block and thereby prevent the slide  20  from being adequately displaced in a direction opposite that of arrow  37 . Consequently, unless the tangs  40  are required to engage with the recesses  42 , the second portion  14  will not engage with the first portion  12  and the second portion  14  will be free to move in a direction opposite that of arrow  37  with respect to the first portion  12 . 
   To release the second portion  14  and the tool bit  24  from the master  16 , the slide  20  is urged in the direction of arrow  37  until it contacts the retainer ring  34 . The second portion  14  is then released and is able to be urged in a direction opposite to arrow  37 . As desired, the different second portion with a different tool bit attached thereto is quickly attached in the manner described hereinabove. 
   Accordingly, a way to quickly change tool bits is provided that ensures that the center longitudinal axes of the tool bit  24 , second portion  14 , master  16  and driven portion of the rotary tool are in alignment. A quick-change capability is provided in which slack is minimized to nearly zero. Furthermore, any desired amount of torque can be transmitted to the tool bit  24 . 
   Referring now to  FIG. 6 , is shown, a modified quick-release tool holder for rotary tools, identified in general by the reference numeral  100 . 
   The modified tool holder  100  includes a modified master  116  and a modified second portion  114 , shown in a slightly spaced-apart orientation. A modified pair of tangs  140  is provided on the modified second portion  114  and a modified pair of recesses  142  is provided in the modified master  116 . The remainder of the modified tool holder  100  is substantially identical to that of the tool holder  10 . 
   The modified tool holder  100  illustrates that it is, of course, possible to switch position of the modified tangs  140  and the modified recesses  142  are compared to where they are disposed on the tool holder  10 . 
   The inside threads  26  of the master  16  are machined therein to match outside threads (not shown) of the driven member of the rotary tool and can, of course, vary accordingly. If desired, the inside threads  26  can be eliminated and the first end  16   a  of the master  16  modified, as desired, to engage with whatever configuration is possessed by the driven member of the rotary tool. 
   APPENDICES A, B, and C, show perspective and other views, including detailed dimensions of the master  16 , slide  20 , and second portion  14 , respectively, for a particular configuration of the tool holder for rotary tools  10 . 
   APPENDIX C also shows a portion of the tool bit  24  including a D-shape  24   a  of an upper portion thereof that is adapted to enter into the corresponding opening  25  that is provided at a first end  14   a  of the second portion  14 . The corresponding opening  25  preferably includes the same D-shape  24   a  and is used to transmit torque from the second portion  14  to the tool bit  24 . The set screw  15  is used, preferably, only to hold the tool bit  24  along its longitudinal length in the corresponding opening  25 . 
   The invention has been shown, described, and illustrated in substantial detail with reference to the presently preferred embodiment. It will be understood by those skilled in this art that other and further changes and modifications may be made without departing from the spirit and scope of the invention which is defined by the claims appended hereto.