Abstract:
A tool securing device capable of clamping a tool to a machine spindle as well as assisting in the removal of a tool from a machine spindle, all in a tool-less manner. The tool securing device includes distal means to be releasably gripped by a machine draw bar as well as means to releasably engage a tool.

Description:
[0001]    This application claims the benefit of U.S. Provisional Patent Application No. 61/331,039 filed May 4, 2010 the entire disclosure of which is hereby incorporated by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention is directed to machinery, in particular metal-removing machinery, and an apparatus for securing a tool to a spindle of a machine. 
       BACKGROUND OF THE INVENTION 
       [0003]    In machining, particularly metal removing machining such as cutting and/or grinding processes for manufacturing gears and other toothed articles, it is known to attach and secure a rotary tool (e.g. face milling cutter, face hobbing cutter, grinding wheel, etc.) to the spindle of a machine via one or more threaded bolts (i.e. clamping bolts) that extend into the face of a rotatable tool spindle. 
         [0004]    In some instances, a rotary tool is secured to a machine spindle by extending a threaded center clamping bolt through the tool head and into the spindle where the end of the center bolt is brought into engagement with a machine draw bar. The draw bar is retracted to exert a pulling force on the center bolt thereby drawing the tool into contact with the machine spindle and clamping the tool thereto. 
         [0005]    With the types of attachment means discussed above, some type of tool, such as a hand-held or pneumatic tool (e.g. wrench) may be required to tighten and/or loosen the clamping bolts. Once the bolts have been loosened and, if applicable, the draw bar has been advanced, removal of the rotary tool from the machine spindle may require additional tools and/or back-off screws to break contact between the tool and the machine spindle. Such tightening and/or loosening operations may be quite time consuming thereby resulting in significant machine down time. 
         [0006]    With the trend toward higher productivity and less machine down time, a manner of securing a tool to a spindle is sought that is faster and involves fewer additional tools than what is currently practiced in the art. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention is directed to a tool securing device capable of clamping a tool to a machine spindle as well as assisting in the removal of a tool from a machine spindle, all in a tool-less manner. The tool securing device includes distal means to be releasably gripped by a machine draw bar as well as means to releasably engage a tool. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is an elevated view of the tool securing device of the present invention. 
           [0009]      FIG. 2  is an axial cross-sectional view of the inventive tool securing device. 
           [0010]      FIG. 3  is an axial cross-sectional view of the inventive tool securing device positioned to secure a tool to a machine spindle. 
           [0011]      FIG. 4  is an enlarged view of  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0012]    Before any features and at least one construction 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 arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other constructions and of being practiced or being carried out in various ways. Also, it is understood that the phraseology and terminology used herein is for the purposes of description and should not be regarded as limiting. 
         [0013]      FIG. 1  shows a tool securing device  2  according to the present invention. The device  2  comprises an axially-extending body portion  4  having a generally circular cross-section and including a proximal flange portion or head  6 , shank portion  8  and distal retention knob  10 . Located at a predetermined distance along the length of the shank portion  8  is a plurality, preferably three or more, of balls  12  (e.g. steel balls) positioned in radially-extending openings  17  spaced circumferentially about the shank portion  8 , preferably at equidistant intervals. Balls  12  are held in the tool securing device  2  by a cover sleeve  14 . 
         [0014]    Tool securing device  2  further includes an internal plunger  16  ( FIGS. 2-4 ) to which a push/pull knob  18  is attached, preferably via threads, at one end thereof. Plunger  16  is movable within an axially-extending internal bore  5  of body portion  4  of tool securing device  2  between positions whereby balls  12  are urged into a radially outward position, or released therefrom, due to different plunger diameter portions located near to the other end of plunger  16 . Namely, an advanced position (shown in  FIGS. 1-4 ) having a first diameter portion, d 1 , whereby balls  12  are urged into their radially outward position, and a retracted position (not shown) where balls  12  are movable inward from their radially outward position due to a reduced second diameter portion, d 2 , thereby creating a cavity-like region  15  wherein the balls  12  may at least partially reside. 
         [0015]    Internal plunger  16  may further comprise a seal  20  (e.g. O-ring) located about the periphery of an upper portion thereof with seal  20  being positionable in a first detent  22  of bore  5  when plunger  16  is in the advanced position, and a second detent  24  of bore  5  when plunger  16  is in the retracted position. A snap ring  26  may be included to prevent the unintentional removal of plunger  16  from bore  5  as well as to prevent any process by-products (e.g. fluids or metal chips) from infiltrating bore  5 . 
         [0016]      FIGS. 3 and 4  show the tool securing device  2  in position to secure a rotary tool  30  (e.g. cutting tool, grinding wheel) to a tool spindle  32  of a machine (e.g. gear manufacturing machine) for rotation about tool axis T. Located within tool spindle  32  is a draw bar  34  which is axially movable within tool spindle  32  and is connected at its inner end to a plurality of gripping fingers  36  located within housing  38  that is secured to the front of machine spindle  32 . Alternatively, spindle  32  and housing  38  may be formed as a one-piece unit. Each gripping finger  36  includes a head portion  40  the underside of which is brought into contact with the radial surface  11  of the retention knob  10  upon tool clamping. 
         [0017]    Draw bar  34  is operable between a first forward position, where the head portion  40  of gripping fingers  36  are axially located beyond the inner end  39  of housing  38  thereby allowing gripping fingers  36  to radially open so as to allow passage of retention head  10  into housing  38 , and a retracted position. Movement of draw bar  34  to the retracted position results in gripping fingers  36  being pulled into housing  38  thereby effecting a radial closing of the gripping fingers whereby the underside of the head portion  40  of each gripping finger  36  is brought into contact with the surface  11  of retention knob  10 . 
         [0018]    As an example of operation, with a rotary tool  30  placed on or against the tool spindle  32  and/or on housing  38  and draw bar  34  in the first forward position, tool securing device  2 , with plunger  16  in the retracted position (i.e. diameter d 2  adjacent balls  12 ), is inserted into the central opening  42  and through the center hole  44  of rotary tool  30  such that the underside  7  of flange portion  6  is seated against the outer surface  46  of shoulder  48 . In this manner, retention head  10  is also inserted into housing  38 . Once inserted, knob  18 , and thus plunger  16 , is pushed inward to the advanced position (i.e. diameter d 1  adjacent balls  12 ) thereby forcing balls  12  radially outward by an amount whereby the balls  12  cannot pass through the center hole  44  and as such, the tool securing device  2  cannot be removed from the rotary tool  30 . Draw bar  34  is then moved to a retracted position thereby closing gripping fingers  36  around retention head  10  and pulling rotary tool  30  into a clamped position against the tool spindle  32  and/or housing  38 . 
         [0019]    When the rotary tool  30  is removed, draw bar  34  is moved to the first forward position thereby releasing retention head  10  from the gripping fingers  36 . Draw bar  34  may then continue forward movement until the front surface  50  of the draw bar contacts the distal end surface  13  of the retention head  10  to loosen or eject the rotary tool  30  from the tool spindle  32  and/or the housing  38 . Loosening of the rotary tool  30  is achieved since the tool securing device  2  cannot move relative to the rotary tool  30  when the balls  12  are in the radially outward position effected by diameter d 1 . 
         [0020]    The tool securing device  2  may be removed from a rotary tool  30  by pulling knob  18  to position reduced diameter, d 2 , adjacent balls  12  thereby rendering balls  12  movable inwardly from their radially outward position due to a reduced second diameter portion, d 2 , wherein the balls  12  may at least partially reside in the cavity-like region  15 . Tool securing device may then be pulled out of rotary tool  30  as any contact between the balls  12  and shoulder  48  will result in the balls  12  moving inwardly such that they will be clear to pass through center hole  44 . 
         [0021]    It should be understood that, alternatively, tool securing device  2  may be positioned in a rotary tool prior to placing the rotary tool on or against a tool spindle and/or on tool gripper housing. 
         [0022]    With the present invention, no tools are required to tighten or loosen the tool securing device  2  from a tool spindle. Additionally, no tools are required to loosen or eject a rotary tool from the tool spindle and/or a tool gripper housing. 
         [0023]    While the invention has been described with reference to preferred embodiments it is to be understood that the invention is not limited to the particulars thereof. The present invention is intended to include modifications which would be apparent to those skilled in the art to which the subject matter pertains without deviating from the spirit and scope of the appended claims.