Abstract:
A small size insert for use with a machine tool for grooving, boring and turning and adapted to be received in a toolholder has an arcuate surface portion and a substantially arcuate-shaped shoulder integral with the body of the insert for accurately positioning the insert within a toolholder.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to cutting tools, namely inserts for machine tools, and more particularly, to small size inserts for grooving and turning.  
           [0003]    2. Description of Related Art  
           [0004]    The art of cutting grooves in a workpiece using a cutting tool, and particularly using an insert secured in a toolholder is well known. The use of an insert in a toolholder for turning, i.e., removing portions of material from a rotating workpiece by causing the insert to traverse along a portion of the longitudinal surface of the workpiece while the insert is sequentially advanced into the surface of the workpiece, is also known.  
           [0005]    In one method of securing the insert during its use, particularly for grooving, cutting or threading, the insert is clamped adjacent one side of a toolholder. In this arrangement the toolholder has a nest or pocket formed by a bottom wall and a side wall, and the insert is held in position by a top clamp. Such an arrangement is illustrated in U.S. Pat. No. 3,754,309, issued to Jones et al. on Aug. 28, 1973.  
           [0006]    Turning, for example in a lathe, advantageously is performed by traversing and removing material from the workpiece in both longitudinal directions. However, attempts to use the same insert within a holder for both grooving and turning, especially during turning in both directions, presents problems in securely and accurately maintaining the insert in position during these operations. In particular, during turning, and most especially upon the workpiece being traversed in the direction outwardly from that side of the holder to which the insert is clamped, the outward end of the insert held by a clamp to the toolholder tends to slip or rotate sideways due to the lateral force of the workpiece on the outward end of the insert. This is particularly the case where the bottom insert supporting surface of the holder is planar and perpendicular to the sides as in U.S. Pat. No. 3,754,309. Even where the bottom insert supporting surface of the holder is not planar, but is angled as in U.S. Pat. No. 6,000,885, issued to Erickson on Dec. 14, 1999, the insert tends to slip or rotate from the holder.  
           [0007]    Attempts have been made to overcome the tendency of the insert to slip or rotate in the holder due to lateral force on the insert, for example by forming a diagonal notch in the insert and angling the clamp element to engage the notch and by forming recessed angled portions in the top and/or bottom surfaces of the insert, as in U.S. Pat. Nos. 3,754,309 and 6,000,885. However, such attempts have generally been imperfect to counter the force exerted on the insert as explained in U.S. Pat. No. 6,000,885. Furthermore, the attempts to date have not been applicable to small-size inserts. Small-size inserts are inserts having grooving widths in the range of from about 0.004 inch to about 0.125 inch and a body diameter of approximately 0.125 inch. Due to the small size of these inserts, it is impractical to attempt to form diagonal notches and recessed portions in the shank portion of the insert, particularly where the insert is a carbide tool insert.  
           [0008]    In another attempt to provide a small-shank tool, and thus one or more small-size inserts, for an automatic lathe or like turning machine, a round or circular cross-sectioned elongated shank was provided to support a pair of rhomboidal-shaped inserts, with fasteners passing through the inserts to hold the inserts to the shank, as in U.S. Pat. No. 6,033,158. However, the support provided for the inserts is limited in size and orientation, i.e., the inserts extend transversely to the axis of the shank, and depend upon fasteners passing through the inserts to resist the forces encountered during cutting, grooving and turning operations. In small-size inserts it is impractical to have an aperture formed therein to receive, if it provided with cause a fastener, a weakened area, particularly if the insert is a carbide tool insert.  
           [0009]    In still another attempt to provide inserts and toolholders which can resist the dislodging of the insert from the holder upon encountering cutting, grooving and turning forces, an insert of generally rectangular cross-section is provided with concave upper and lower clamping surfaces which cooperate with concavely-shaped clamping surfaces of a toolholder, as in U.S. Pat. No. 5,076,738. However, the generally rectangular-shaped inserts having arcuate clamping surfaces do not lend themselves for use as small-size inserts in which it would be extremely difficult to form concave upper and lower clamping surfaces, particularly where the insert is a carbide tool insert.  
           [0010]    Thus, there exists a need for small-sized inserts which are configured to resist forces exerted on the insert, particularly during turning.  
         SUMMARY OF THE INVENTION  
         [0011]    It is an object of the present invention to provide a small-size insert which is securely held within a holder even when encountering lateral forces which tend to move the insert out of position with respect to the holder.  
           [0012]    It is another object of the invention to provide a small-size insert which does not require apertures, recesses, notches or concave surfaces in order to be securely held in position during grooving and turning.  
           [0013]    Another object of this invention is to provide an insert with means to easily and accurately position the insert within a toolholder.  
           [0014]    It is still another object of this invention to provide a small size insert which can be securely held in position during grooving, cutting, as well as during turning in both directions along the workpiece.  
           [0015]    These and other objects and advantages of the present invention will be apparent from the following description.  
           [0016]    In accordance with the present invention, a small-size insert is provided for use with a machine tool for grooving, boring and turning. The insert comprises a body, a shoulder integral with the body and extending outwardly from the body, and a cutting portion extending from one end of the body. The body of the insert has a length greater than its width, a first generally arcuate surface portion extending along its length which forms a pair of opposing longitudinal edges, and a second substantially planar portion along the length of the body forming a pair of opposing longitudinal edges, each of which are contiguous with one longitudinal edge of the first generally arcuate portion. The body is adapted to be received within a toolholder having an arcuate insert-receiving portion with the generally arcuate first surface portion of the body residing in the arcuate insert receiving portion of the toolholder. The shoulder integral with the body preferably is arcuate-shaped and extends radially outward from at least a portion of the generally arcuate first portion of the body. The shoulder of the insert permits the insert to be quickly, easily and accurately positioned in a toolholder having an arcuate insert-receiving portion by positioning the shoulder abutting against a finished end portion of the holder. In this manner the shoulder of the insert abutting the end of the toolholder is self orienting with respect to the toolholder, and when clamped to the holder by a clamp exerting clamping force on the substantially planar portion of the body of the insert, the clamping arrangement with the insert provides rigidity to the insert with respect to the toolholder, and affords repeatability in positioning and orientation upon changing inserts with the same toolholder.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0017]    [0017]FIG. 1 is a fragmentary perspective view of an insert in accordance with the present invention mounted and clamped to a toolholder and secured thereto;  
         [0018]    [0018]FIG. 2 is another fragmentary perspective view of an insert as in FIG. 1 mounted to another toolholder taken from a different orientation;  
         [0019]    [0019]FIG. 3 is a perspective view of an insert in accordance with one embodiment of the present invention;  
         [0020]    [0020]FIG. 4 is a top view of the insert of FIG. 3;  
         [0021]    [0021]FIG. 5 is a left side view of the insert of FIG. 3;  
         [0022]    [0022]FIG. 6 is a front end view of the insert of FIG. 3;  
         [0023]    [0023]FIG. 7 is a perspective view of another insert in accordance with the present invention;  
         [0024]    [0024]FIG. 8 is a top view of the insert of FIG. 7;  
         [0025]    [0025]FIG. 9 is a front end view of the insert of FIG. 7;  
         [0026]    [0026]FIG. 10 is a perspective view of still another insert of the present invention;  
         [0027]    [0027]FIG. 11 is a top view of the insert of FIG. 10;  
         [0028]    [0028]FIG. 12 is a front end view of the insert illustrated in FIG. 10;  
         [0029]    [0029]FIG. 13 is a perspective view of the toolholder shown in FIG. 1 with which the insert of the present invention may be utilized;  
         [0030]    [0030]FIG. 14 is a perspective view of the toolholder shown in FIG. 2, with which the insert of the present invention may be used; and  
         [0031]    [0031]FIG. 15 is a perspective view of the clamp shown in FIGS. 1 and 2, which may be used in cooperation with the insert of the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0032]    In a preferred embodiment of the present invention as illustrated in FIGS.  3 - 6 , and as illustrated in FIGS. 1 and 2 mounted to a toolholder, an insert  10  of this invention is provided having a body  12  which has a length greater than its width, comprised of an end  14 , a first generally arcuate surface portion  16 , and a second substantially planar portion  18 . Generally arcuate surface portion  16  extending along the length of body  12  forms a pair of opposing longitudinal edges  20 ,  22 , and substantially planar portion  18  also extending along the length of body  12  forms a pair of opposing longitudinal edges  24 ,  26 , each of which are contiguous with one of the longitudinal edges  22 ,  24  of the first generally arcuate surface portion  16 . Insert  10  further comprises a substantially arcuate-shaped shoulder  28  which is integral with body  12  and extends outwardly from at least a portion of arcuate first surface portion  16  of body  12 . Insert  10  also comprises a cutting portion  30  extending from end  14  and shoulder  28 .  
         [0033]    In the embodiment shown in FIGS.  3 - 6 , cutting portion  30  is roughly D-shaped in cross-section and has a width at its upper surface of approximately 0.020 inch. As best shown in FIG. 5, the distal end  32  of cutting portion  30  is inclined downwardly and rearwardly to prevent binding in the groove formed in a workpiece during grooving, although other shaped cutting portions can be present as part of the insert as desired. In the embodiment shown, only the upper edges of distal end  32  of cutting portion  30  are utilized in turning.  
         [0034]    As best shown in FIGS. 3 and 6, the cutting portion  30  preferably includes an arcuate surface portion  34  and shoulder  28  extends radially outwardly beyond the arcuate surface portion  34 . Also preferably, shoulder  28  extends radially outwardly from body  12  adjacent cutting portion  30  substantially along the circumference defined by the first generally arcuate surface portion  16  of body  12 . Further, as shown, the body  12  at end  14  includes a downwardly beveled portion  36  extending from substantially planar portion  18  adjacent end  14  at its junction with shoulder  28  to cutting portion  30 . Still further, upper surface  38  of cutting portion  30  is substantially planar and extends from beveled portion  36  to the distal end  32  of the cutting portion. As best shown in FIGS. 4 and 6, cutting portion  30  is coextensive at its proximal end integral with body  12  with at least a portion of shoulder  28 . Cutting portion  30  therefore is at least slightly offset from body  12  with respect to the longitudinal axis of body  12 , as best seen in FIG. 4.  
         [0035]    FIGS.  7 - 9  show an insert  40  in accordance with the present invention, which is identical to insert  10  shown in FIGS.  3 - 6 , except that the cutting portion  42  has a width at its upper surface of approximately 0.040 inch and is roughly D-shaped in cross-section as shown in FIG. 9. In all other respects, insert  40  is identical to insert  10 , and the same reference numerals and the description with respect to insert  10  applies to insert  40  and is incorporated herein.  
         [0036]    Similarly, FIGS.  10 - 12  illustrate an insert  50  in accordance with this invention which is identical to inserts  10  and  40 , except that the cutting portion  52  has a width at its upper surface of approximately 0.060, and is roughly D-shaped, as shown in FIG. 12. In all other respects, insert  50  is identical to inserts  10  and  40 , and the same reference numerals and the same description applies to insert  50  and is incorporated herein.  
         [0037]    Inserts  10 ,  40  and  50  are intended to be utilized with a toolholder, such as toolholder  60  shown in FIGS. 1 and 13, or toolholder  90  shown in FIGS. 2 and 14. The toolholder  60  has a body  62  having an elongated arcuate portion  64  and an elongated substantially planar portion  66 . Distal end portion  68  of body  62  has a planar surface  70  at approximately the horizontal diameter of body  62  and a pair of longitudinal grooves  72  adjacent each side of end portion  68  adapted to receive an insert  10 ,  40  or  50 . Either groove  72  can be used, depending on whether right hand or left hand positioning of the insert is desired. Distal end portion  68  also serves as an abutment against which shoulder  28  of the insert is placed to accurately position the insert in the groove and provide repeatability of accurately positioning replacement inserts. The insert is held in position in one of the grooves  72  by means of a clamp  74  which is secured to end portion  68  by means of a fastener, such as a machine screw  76  passing through an aperture  78  in clamp  74  and into a threaded hole  80  formed in end portion  68 . Clamp  74 , as it is tightened against planar surface  70  and end portion  68  by machine screw  74  causes the insert to self-orient by rotating its body  12  to cause the substantially planar portion  18  to align horizontally with the bottom surface of the clamp. Inserts  10 , 40   50  secured in toolholder  60  are particularly useful for grooving and turning of a workpiece.  
         [0038]    The body of toolholder  90  is similarly configured as compared to body  62  of toolholder  60 , and the same reference numbers and description as for holder  60  and in FIGS. 1 and 13 are utilized for identical configuration elements for toolholder  90  and in FIGS. 2 and 14. Toolholder  90  differs from toolholder  60  in the configuration of its distal end portion  92 . End portion  92  also has a planar surface  94 , but a single insert-receiving groove  96  is provided transversely to the axis of body  62  adjacent the distal end  98  of end portion  92 . Further, as shown in FIG. 14, two threaded holes  100 , 102  are provided in planar surface  94  and into end portion  92 , the holes  100 ,  102  being spaced from each other and aligned transversely to the axis of body  62 . Clamp  74  is utilized to orient and secure an insert in groove  96 , with shoulder  28  of the insert abutting either end of groove  96  depending on whether the cutting portion  30 ,  42 ,  52  of the insert is to extend to the right or left from end portion  92 . Insert  10 ,  40 ,  52  secured in toolholder  90  is particularly useful for internal face boring of a workpiece.  
         [0039]    While a particular embodiment of the grooving and turning insert of the invention has been shown and described, it will be appreciated by those skilled in the art that changes and modifications may be made thereto without departing from the invention in its broader aspects and as set forth in the following claims.