Abstract:
A cutting tool body that is adapted for use in milling operations comprises at least one pocket for supporting a cutting insert. The pocket is defined, at least in part, by a cylindrical wall and a seating surface within the tool body. At least one passage is provided through the tool body for evacuating chips upward and away from the surface of a workpiece. The seating surface of the pocket extends radially inward from the cylindrical wall and intersects the passage through the tool body. At least one slot traverses the pocket to separate a part of the tool body into first and second portions, at least one of which is movable relative to the other for clamping the cutting insert into the pocket.

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates in general to cutting tools and, more particularly, to a tool body and inserts that are especially suitable for use in metal cutting operations. 
   Cutting tools for metal cutting operations are well known. A conventional metal cutting tool typically comprises a tool body that is adapted to mate with a cutting machine. The tool body has a working end and one or more pockets in the working end. A conventional pocket ordinarily includes a floor and two seating surfaces. The pockets are provided for receiving cutting inserts. A retention screw threaded into a threaded hole in the tool body holds the insert in the pocket. 
   Conventional metal cutting tools are adapted for use in removing material from a metal workpiece. The material removed is commonly referred to as a chip. Chips are often deposited on the workpiece and subsequently re-cut by the cutting inserts, resulting in damage to the cut surface of the workpiece. 
   What is needed is a metal cutting tool that prevents or reduces the risk of chips being deposited on a metal workpiece. 
   BRIEF SUMMARY OF THE INVENTION 
   Generally speaking, the invention is directed to a cutting tool body that is adapted for use in metal cutting operations. The tool body comprises at least one pocket for supporting a cutting insert. The pocket is defined, at least in part, by a cylindrical wall and a seating surface within the tool body. At least one passage extends through the tool body. The seating surface extends radially inward from the cylindrical wall and intersects the passage. At least one slot in the tool body traverses the pocket to separate a part of the tool body into first and second portions. At least one of the portions is movable relative to the other portion for clamping the cutting insert into the pocket. 
   The invention is further directed to a cutting tool, as summarized above, having a cutting insert held within the pocket by a clamping screw that is adapted to be inserted through the first portion of the tool body and threaded into a hole that extends transversely through the second portion of the tool body. Tightening the screw draws the two portions toward one another to clamp the tubular cutting insert in the pocket. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further features of the present invention, as well as the advantages derived therefrom, will become clear from the following detailed description made with reference to the drawings in which: 
       FIG. 1  is a perspective view of a cutting tool body; 
       FIG. 2  is a cross-sectional view of the tool body taken along the line  2 — 2  in  FIG. 1 ; 
       FIG. 3  is another perspective view of the tool body; 
       FIG. 4  is a cross-sectional view of the tool body taken along the line  4 — 4  in  FIG. 3 ; 
       FIG. 5  is an enlarged view of the tool body shown in  FIG. 4  with a tubular cutting insert therein; 
       FIGS. 6A and 6B  are perspective views of tubular cutting inserts with cylindrical external chamfers; 
       FIGS. 7A and 7B  are perspective views of tubular cutting inserts with cylindrical internal and external chamfers; 
       FIGS. 8A–8C  are perspective views of tubular cutting inserts with cylindrical internal chamfers; 
       FIG. 9  is a perspective view of a tubular cutting insert with an elliptical external chamfer; 
       FIG. 10  is a perspective view of a tubular cutting insert with an elliptical internal chamfer; 
       FIG. 11  is an environmental side elevational view of the cutting tool showing chip flow in an upward and outward direction; and 
       FIG. 12  is an enlarged partial cross-sectional view of the tool body supporting a tubular cutting insert having a cylindrical cutting edge at both ends. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   With reference now to the drawings, wherein like numerals designate like components throughout all of the several figures, there is illustrated in  FIG. 1  a tool body  10  having shank  12 , which is adapted to be supported by a metal cutting machine, a generally cylindrical portion  14 , and a working end  16 , which is adapted to support one or more cutting inserts. 
   The shank  12  shown is a hollow taper shank, which is particularly suitable for high-speed operations. It includes a relief  18 , which allows for expansion of the shank  12  when inserted into the cutting machine, and two holes  20  that are engaged by balls in the cutting machine to pull the shank  12  therein. It should be understood that the tool body  10  may employ other shanks and though the tool body  10  is well suitable for high-speed metal cutting operations, the tool body  10  may be suitable for other metal cutting operations. 
   The working end  16  has one or more pockets  22  therein for supporting the cutting inserts. Chip gashes  24  may be provided about the periphery of the working end  16  adjacent each pocket  22 . The chip gashes  24  may be formed by scooping material from the working end of tool body  10  to enable the cutting edge of the cutting inserts to be exposed to a workpiece. 
   When producing the tool body  10 , if the chip gashes  24  are cut into the tool body  10  prior to drilling the pockets  22 , the chip gashes  24  each provide a surface suitable for drilling the pockets  22 . The chip gashes  24  provide clearance for the cutting insert so size of the chip gashes  24  is generally dependent, at least in part, on the engagement of the cutting edge of the cutting insert with the workpiece and the number of pockets  22  in the tool body  10 . The larger the chip gash  24 , the better engagement the cutting edge of the cutting insert has with the workpiece. Otherwise, the chip gashes  24  are quite adjustable. 
   As illustrated in  FIG. 2 , the pockets  22  may be defined, at least in part, by a cylindrical wall  26  and a shoulder or seating surface  28  within the tool body  10 . The seating surface  28  may extend radially inward from the cylindrical wall  26  to a passage  30 . The passage  30  may be in the form of a hole that passes transversely through the tool body  10  with entrance and exit points. 
   As illustrated in  FIGS. 3 and 4 , slots  32  are provided in the tool body  10  that traverse the pockets  22 . The slots  32  may run the axial length of the pockets  22  and passages  30 , or be provided in the area of the pockets  22 , and may be parallel to the pockets  22  and/or passages  30 . The slots  32  separate a part of the tool body  10  into the first and second portions  34 ,  36 . The slots  32  may terminate in the tool body  10  along stress relief holes  38 , which may extend the length of the slots  32 . The stress relief holes  38  encourage movement of the first and second portions  34 ,  36  of the tool body  10  to produce a peripheral clamp, which may clamp substantially about the full periphery of a cutting insert. 
   Clamping action is effected by clamping screws  40 , as shown in  FIG. 4 . Each clamping screw  40  is adapted to be inserted through the first portion  34  of the tool body  10 , preferably through a counter-bored hole  42 , and threaded into a hole  44  that extends transversely through a second portion  36  of the tool body  10 . The counter-bored hole  42  is preferably larger than the head of the screw  40  to permit the head of the screw  40  to be recessed in the tool body  10 . Tightening the screw  40  draws the two portions  34 ,  36  toward one another. The screw  40  is angled upwardly and outwardly, which is a most suitable orientation of the screw  40  under centrifugal forces of the tool body  10  during a metal cutting operation because the centrifugal forces function of pull the screw  40  into the threaded hole  44 . 
   The pockets  22  are adapted to support tubular cutting inserts  46 , as shown in  FIG. 5 . Tightening the screw  40 , as described above, holds the cutting insert  46  firmly in the pocket  22 . The passage  30  through the tool body  10  cooperates with a hollow interior through the tubular cutting inserts  46  to form a flute. The passages  30  may be straight or could have other shapes and orientations, such as a helical orientation. 
   As clearly shown in  FIG. 6A , the cutting inserts  46  may be formed at least in part by a cylindrical wall  48  having an outer surface  50  and an inner surface  52 , bounding a hollow interior  54 . A cylindrical cutting edge  56  is provides at one end of the cutting inserts  46 . An external cylindrical chamfer  58  may extend from the outer surface  50  to the cylindrical cutting edge  56 . The angle of the chamfer  58  may be dependent at least in part on the initial angle of the cylindrical cutting edge  56  (i.e., prior to shaping or honing the cylindrical cutting edge  56 ) and the ability of the chamfer  58  to direct chip flow through the passage  30 , which will become more apparent upon reading the description below. 
   The axial length (i.e., horizontal distance when viewing  FIG. 6A ) of the tubular cutting insert  46  is mostly economically driven. The tubular cutting insert  46  may be sufficiently long to be clamped securely in the pocket  22  yet not so long as to waste material resources (i.e., carbide, metal cutting ceramic, cubic boron nitride, etc.). Ease of producing the tubular cutting insert  46  may also play a role in determining the length of the tubular cutting insert  46 . 
   The cylindrical wall  48  of the tubular cutting insert  46  may be sufficiently thick to endure being clamped in the pocket  22  but sufficiently narrow to provide adequate or unobstructed chip flow through the hollow interior  54  of the tubular cutting insert  46 . If the tubular cutting insert  46  is a carbide insert, clamping the tubular cutting insert  46  in the pocket  22  will take advantage of the compressive strength of the carbide. 
   The cutting inserts  46  may have a T-land  60  or other shape, and may be honed to make the cutting edge  56  blunt, so as not to be sharp to the point of being brittle. The width (the vertical distance when viewing  FIG. 6A ) of the T-land  60  may be dependent at least in part on the feed rate and cutting depth of the tool body  10 . Moreover, the width of the T-land  60  is preferably sufficiently large to engage the seating surface  28  (shown in  FIG. 5 ), unless the tubular cutting insert  46  has one cutting edge, like the cutting insert  46  shown. 
   As shown in  FIG. 6B , the tubular cutting insert may be provided with one or more axial grooves, or other geometric features, as generally indicated at  62 , in the inner surface of the cylindrical wall to encourage the chip flow through the hollow interior of the cutting insert. 
   As shown in  FIGS. 7A and 7B , the tubular cutting insert may be provided with internal and external chamfers  64 ,  66  with a cylindrical cutting edge  68  therebetween. 
   As shown in  FIGS. 8A through 8C , the tubular cutting insert may be provided with an internal chamfer  70  that extends from the inner surface of the cylindrical wall to the cutting edge  72 . Moreover, the outer surface of the cylindrical wall of the tubular cutting insert may be provided with one or more geometric features, such as one or more radial annular grooves  74 , as shown in  FIG. 8A , one or more axial grooves  76 , as shown in  FIG. 8B , or some other suitable feature, such as a rough finish  78 , as shown in  FIG. 8C . The geometric features may cooperate with the pocket to aid in securely clamping the tubular cutting insert in the pocket. It should be noted that the pocket may be provided with geometric features that mate with the geometric features on the tubular cutting insert. 
   It should be noted that the tool body may be provided with pocket for supporting cutting inserts having other shapes, such as elliptical, square, octagonal, or hexagonal, or other polygonal shapes. For example, an elliptical cutting insert  80  with the external chamfer  82  shown in  FIG. 9 , and the elliptical cutting insert  84  with the internal chamfer  86  shown in  FIG. 10 . The narrow dimension of the elliptical cutting insert would be very suitable for rough cutting operations while the wide dimension of the elliptical cutting insert would be very suitable for finishing operations. The use of various shaped or oriented cutting inserts may dictate the need for cutting tools having pockets with different shapes or orientations. Alternatively, cutting inserts of differing shapes may be supported in different orientations by cartridges that may be clamped within a pocket, such as the cylindrical pocket  22  shown and described above. 
   The operation of the tool body  10  is best understood with reference to  FIG. 11 . The tool body  10  is supported in an adapter (not shown) for adapting the tool body  10  to the spindle of a metal cutting machine (also not shown). A tubular cutting insert, as described above, may be secured in the pocket  22  with the clamping screw  40 , as set forth above. As the spindle turns, the tubular cutting insert engages a workpiece W, as shown in  FIG. 11 , to remove material from the surface of the workpiece W. As material is removed from the surface of the workpiece W, chips are discharged upwardly and outwardly through the passages  30  and away from the surface of the workpiece W. This avoids or reduces the risk that damage will occur to the finished workpiece W, which is generally encountered when using a conventional cutting tool, which deposits chips on the workpiece W and re-cuts the chips and damages the surface of the workpiece W. Directing the chips away from the workpiece W further eliminates or reduces to risk of re-cutting (i.e., cutting into chips on the surface of the workpiece W). 
   It should be note that the invention is not intended to be limited to the tool body and tubular cutting insert shown and described above. For example, the clamping screw may be angled downwardly and inwardly, in the direction of the centrifugal forces of the tool body during a metal cutting operation. Moreover, a tubular cutting insert  88  may have a cylindrical cutting edge  90  at both ends, as shown in  FIG. 12 . 
   It should be appreciated that the tubular cutting inserts may be indexable, or adapted to be repositioned in the pockets. The number of indexable positions depends at least in part on the depth of the cut made by the tubular cutting insert. Geometric features, such as those described above, may aid in indexing the tubular cutting insert in discrete positions. 
   It should further be appreciated that the passages through the tool body may provide a smooth transition with the inner surface of the cylindrical wall of the tubular cutting insert, resulting in a continuous or uninterrupted and unobstructed passage for efficient and effective evacuation of chips from the workpiece W through the passages. 
   It should be noted that the bottom of the passages illustrated is directed neither radially or tangential to the periphery of the tool body but rather extends through the tool body, up and away from the cutting plane. In this way, the passages break out of the tool body without interfering with the pockets, the cutting insert, the screws, or holes. 
   Any documents, patents and patent applications referred to herein are hereby incorporated by reference. 
   While the invention has been specifically described in connection with certain specific embodiments thereof, it is to be understood that this is by way of illustration and not of limitation, and the scope of the appended claims should be construed as broadly as the prior art will permit.