CLIAMS:1. A cutting tool (10), comprising:
a tool body (12) comprising a cutting end (14) with a plurality of circumferentially-spaced insert pockets (16), and a mounting end (18) opposite the cutting end (14), each insert pocket (16) including a bottom support wall (22), a first support side wall (24), a second support side wall (26) and a radially-inward rear wall (28);
a cutting insert (30) mounted in the insert pocket (16), each cutting insert (30) comprising a polygonal body (31) that is symmetric about a central axis CL, and including a top surface (32), a bottom surface (34) and at least six side surfaces (36), a cutting edge (40) formed at an intersection between one of the top surface (32) and the bottom surface (34) and each side surface (36), and a corner (41) separating each cutting edge (40) from an adjacent cutting edge (40); and
an anti-rotation mechanism comprising a pin (29) protruding from the radially-inward rear wall (28) of the insert pocket (16) and a recess (49) formed in at least one side surface (36) of the cutting insert (30) for receiving a portion of the pin (29) to prevent movement of the cutting insert (36) when mounted in the insert pocket (16).

2. The cutting tool (10) according to Claim 1, wherein the tool body (12) further comprises a plurality of circumferentially-spaced clamping element pockets (17) and a clamping element (50) mounted therein.

3. The cutting tool (10) according to Claim 2, wherein the clamping element (50) comprises an arcuate-shaped top surface (52), a bottom surface (54), and a pair of opposing side surfaces (56, 58).

4. The cutting tool (10) according to Claim 3, wherein the bottom surface (54) of the clamping element (50) contacts a seating surface (46, 47) of the cutting insert (30) when the cutting insert (30) is mounted in the insert pocket (16).

5. The cutting tool (10) according to Claim 1, wherein the cutting insert (30) further comprises a rake surface (44) extending inwardly from each cutting edge (40), and a seating surface (46, 47) adjacent the rake surface (44) for contacting the bottom support surface (22) of the insert pocket (16) when the cutting insert (30) is mounted in the insert pocket (16).

6. The cutting tool (10) according to Claim 5, wherein the seating surface (46, 47) is coplanar with the plurality of cutting edges (40).

7. The cutting tool (10) according to Claim 5, wherein the seating surface (46, 47) projects above the plurality of cutting edges (40).

8. The cutting tool (10) according to Claim 5, wherein the seating surface (46, 47) is polygonal in shape.

9. The cutting tool (10) according to Claim 1, wherein the cutting insert (30) is octagon-shaped with a total of eight side surfaces (36).

10. The cutting tool (10) according to Claim 1, wherein the cutting tool (10) comprises a milling cutter.

11. An indexable cutting insert (30), comprising:
a polygonal body (31) that is symmetric about a central axis CL, and including a top surface (32), a bottom surface (34) and a plurality of side surfaces (36);
a plurality of cutting edges (40) formed at an intersection between one of the top surface (32) and the bottom surface (34) and each side surface (36); and
a corner (41) separating each cutting edge (40) from an adjacent cutting edge (40),
wherein the top surface (32) includes a rake surface (44) extending inwardly from each cutting edge (40), and a seating surface (46, 47) adjacent the rake surface (44), and
wherein each side surface includes a recess (49) formed therein, the recess (49) capable of receiving a portion of a pin (29) protruding from a radially-inward rear wall (28) of an insert pocket (16) of a cutting tool (10) to prevent movement of the cutting insert (30) when mounted in the insert pocket (16).

12. The cutting insert (30) according to Claim 11, wherein the seating surface (46, 47) is coplanar with the plurality of cutting edges (40).

13. The cutting insert (30) according to Claim 11, wherein the seating surface (46, 47) projects above the plurality of cutting edges (40).

14. The cutting insert (30) according to Claim 11, wherein the seating surface (46, 47) is polygonal in shape.

15. The cutting insert (30) according to Claim 11, wherein the cutting insert (30) is octagon-shaped with a total of eight side surfaces (36).

16. An anti-rotation mechanism for a cutting tool (10) comprising a pin (29) protruding from a radially-inward rear wall (28) of an insert pocket (16) of the cutting tool (10), and a recess (49) formed in at least one side surface (36) of a polygonal-shaped cutting insert (30) for receiving a portion of the pin (29) to prevent movement of the cutting insert (36) when mounted in the insert pocket (16).
,TagSPECI:FIELD OF THE INVENTION
The invention pertains to the field of cutting tools. More particularly, the invention pertains to an anti-rotation mechanism for preventing movement of a cutting insert when mounted in an insert pocket of the cutting tool.

DESCRIPTION OF RELATED ART
One of the major disadvantages with polygonal-shaped cutting inserts having multiple side surfaces (i.e. multiple cutting edges), and in particular, with cutting inserts with more than six side surfaces is proper seating of the cutting insert in the insert pocket of the cutting tool. Due to the higher angle between adjacent side surfaces as compared to a cutting insert with a fewer number of side surfaces, the cutting insert with a large number of side surfaces, and in particular more than six side surfaces, has a tendency to rock (i.e. slight rotational movement) when mounted in the insert pocket. Thus, it would be desirable to prevent the rocking of the cutting insert, particularly cutting inserts with more than six side surfaces, when mounted in the insert pocket.

SUMMARY OF THE INVENTION
The problem of properly seating a polygonal-shaped cutting insert having a large number of side surfaces in the insert pocket is solved by providing an insert pocket having a pin protruding from a rear wall of the pocket and a cutting insert having a corresponding recess on the side surface adapted to receive the pin.

In one aspect of the invention, a cutting tool comprises a tool body including a cutting end with a plurality of circumferentially-spaced insert pockets, and a mounting end opposite the cutting end. Each insert pocket includes a bottom support wall, a first support side wall, a second support side wall and a radially-inward rear wall. A cutting insert mounted in the insert pocket and comprising a polygonal body that is symmetric about a central axis CL, and including a top surface, a bottom surface and at least six side surfaces. A cutting edge is formed at an intersection between one of the top surface and the bottom surface and each side surface, and a corner separates each cutting edge from an adjacent cutting edge. An anti-rotation mechanism comprises a pin protruding from the radially-inward rear wall of the insert pocket and a recess formed in at least one side surface of the cutting insert for receiving a portion of the pin to prevent movement of the cutting insert when mounted in the insert pocket.

In another aspect of the invention, an indexable cutting insert comprises a polygonal body that is symmetric about a central axis CL, and including a top surface, a bottom surface and a plurality of side surfaces. A plurality of cutting edges are formed at an intersection between one of the top surface and the bottom surface and each side surface. A corner separates each cutting edge from an adjacent cutting edge. The top surface includes a rake surface extending inwardly from each cutting edge, and a seating surface adjacent the rake surface. Each side surface includes a recess formed therein. The recess is capable of receiving a portion of a pin protruding from a radially-inward rear wall of an insert pocket of a cutting tool to prevent movement of the cutting insert when mounted in the insert pocket.

In another aspect of the invention, an anti-rotation mechanism for a cutting tool comprises a pin protruding from a radially-inward rear wall of an insert pocket of the cutting tool, and a recess formed in at least one side surface of a polygonal-shaped cutting insert for receiving a portion of the pin to prevent movement of the cutting insert when mounted in the insert pocket.

BRIEF DESCRIPTION OF THE DRAWINGS
While various embodiments of the invention are illustrated, the particular embodiments shown should not be construed to limit the claims. It is anticipated that various changes and modifications may be made without departing from the scope of this invention.
FIG. 1 is a side view of a cutting tool with an anti-rotation mechanism according to an embodiment of the invention;

FIG. 2 is an exploded view of the cutting with the anti-rotation mechanism according to an embodiment of the invention;
FIG. 3 is an isometric view of an insert pocket of the tool body of the cutting tool with a pin protruding from a radially-inward rear wall of the insert pocket according to an embodiment of the invention;

FIG. 4 is an enlarged view of the insert pocket of FIG. 3 according to an embodiment of the invention;

FIG. 5 is an isometric view of the cutting insert with a recess formed in the side surface according to an embodiment of the invention;

FIG. 6 is a top view of the cutting insert of FIG. 5; and

FIG. 7 is a side view of the cutting insert of FIG. 5.

DETAILED DESCRIPTION OF THE INVENTION
Referring now to FIGS. 1 and 2, a cutting tool 10, for example, a milling cutter, is shown according to an embodiment of the invention. The milling cutter 10 comprises a tool body 12 including a cutting end 14 with a plurality of circumferentially-spaced insert pockets 16, a plurality of circumferentially-spaced clamping element pockets 17, and a mounting end 18 opposite the cutting end 14. The tool body 12 is designed to be rotatably driven about a central, longitudinal axis 13. In the illustrated embodiment, the milling cutter 10 includes a total of ten (10) pockets 16. However, it will be appreciated that the invention is not limited by the number of pockets 16, and that the invention can be practiced with any desirable number of pockets that provide the desired cutting capabilities. Each of the pockets 16 is capable of receiving a clamping element assembly, shown generally at 20. The clamping element assembly 20 comprises an indexable cutting insert, shown generally at 30, and a clamping element, shown generally at 50.

Referring now to FIGS. 3 and 4, each insert pocket 16 includes a bottom support wall 22, a first side support wall 24, a second side support wall 26 and a radially-inward rear wall 28. When mounted in the insert pocket, the cutting insert 30 contacts the bottom support wall 22, the first side support wall 24 and the second side support wall 26 to provide 3-point contact between the cutting insert 30 and the insert pocket 16. It is noted that the cutting insert 30 does not contact the radially-inward rear wall 28 when mounted in the insert pocket 16.

One aspect of the invention is that the rear wall 28 has an aperture 28a adapted to receive a pin 29, such as a dowel pin, and the like. The pin 29 can be secured within the aperture 28a using any well-known means in the art, such as brazing, press-fitting, and the like. Once the pin 29 is secured within the aperture 28a, a portion of the pin 29 protrudes from the radially inward rear wall 28 a predetermined distance, d, so as to be able to sufficiently contact the cutting insert 30 when mounted in the insert pocket 16. The magnitude of the distance, d, depends on the relative dimensions of the insert pocket 16 and the cutting insert 30.

As shown in FIGS. 5-7, the cutting insert 30 has a polygonal body 31 made of wear-resistant material. Although other geometric shapes are possible, the cutting insert 30 is of a generally octagonal shape that is symmetric about a central axis CL, and includes a top surface 32, a bottom surface 34 and a plurality of side surfaces 36. However, it will be appreciated that the invention is not limited by the geometric shape of the cutting insert 30, and that the invention can be practiced with any desirable geometric shape, such as triangular, rectangular, and the like. As shown in FIG. 3, each side surface 36 has an angle 38 of approximately forty-five (45) degrees with respect to an adjacent side surface 36. Because the cutting insert 30 is symmetric about all three axes (x-, y-, z-), only the top surface 32 will be described in detail herein for brevity. However, it will be appreciated that any discussion of the top surface 32 applies to the bottom surface 34.

In the illustrated embodiment, each side surface 36 is substantially perpendicular to both the top and bottom surfaces 32, 34. In other words, the top and bottom surfaces 32, 34 are substantially parallel to each other and perpendicular to the side surfaces 36. That is, the side surfaces 36 have a facet clearance angle of zero (0) degrees. Thus, both the top and bottom surfaces 32, 34 of the cutting insert 30 can be presented to the workpiece (not shown). One of the top and bottom surface 32, 34 and two of the side surfaces 36 engage the pocket 16 when the cutting insert 30 is mounted in the insert pocket 16 of the tool body 12 during cutting operations. More specifically, one of the top and bottom surfaces 32, 34 contacts the bottom support wall 22 and two side surfaces 36 that are ninety degrees apart from each other contact the first and second side surfaces 24, 26 of the insert pocket 16 when the insert 30 is properly mounted in the tool body 12.

The cutting insert 30 includes a plurality of cutting edges 40 formed at the intersection between the top surface 32 and each side surface 36. A corner 41 separates each cutting edge 40 from an adjacent cutting edge 40. Similarly, the cutting insert 30 includes a plurality of cutting edges 42 formed at the intersection between the bottom surface 34 and each side side surface 36. A corner 43 separates each cutting edge 42 from an adjacent cutting edge 42. Preferably, each corner 41, 43 has a radius in the range of approximately 0.5 to 3.0 mm. However, the invention can be practiced with any desirable corner radius. As shown in FIG. 7, each cutting edge 40, 42 has a concave profile.

It will be appreciated that each of the cutting edges 40, 42 can be indexed into an active position and effectively utilized in the milling cutter 10. Thus, the cutting insert 30 of the invention can be indexed sixteen (16) times (i.e. 8 times when the top surface 32 is presented to the workpiece and 8 times when the bottom surface 34 is presented to the workpiece), unlike conventional rectangular or square cutting inserts. It will be appreciated that the number of cutting edges 40 and the number of times that the cutting insert 30 can be indexed depends on the geometric shape of the cutting insert 30. For example, a hexagon shaped cutting insert having a total of twelve (12) cutting edges can be indexed twelve (12) times (i.e. 6 times when the top surface is presented to the workpiece and 6 times when the bottom surface is presented to the workpiece).

The top surface 32 (and also the bottom surface 34) includes a rake surface 44 that may be substantially planar and extends inwardly and downwardly from the cutting edge 40, 42. The rake surface 44 form a flow pattern for efficient chip ejection. The top surface 32 (and bottom surface 34) also includes a raised polygonal-shaped seating surface 46, 48. The seating surfaces 46, 48 can be any desirable shape. In the illustrated embodiment, the seating surfaces 46, 48 are generally polygonal in shape in which two opposite vertices of the polygon are bisected by a plane 39 extending from the central axis, CL, and passing through the corners 41, 43 of the cutting insert 30. The seating surfaces 46, 48 are generally planar and identical to each other. The seating surfaces 46, 48 may be substantially coplanar with the cutting edges 40, 42, or alternatively project above the cutting edges 40, 42 by a height that is preferably in the range of about 0.05 mm to about 1.00 mm, as shown in FIG. 7. The seating surfaces 46, 48 serve as an insert support-seating surface and contact the bottom support wall 22 of the insert pocket 16 when the cutting insert 30 is properly mounted in the milling cutter 10.

Another aspect of the invention is that one or more of the side surfaces 36 includes a recess 49 adapted to receive a portion of the pin 29 projecting from the rear wall 28 of the insert pocket 16. The combination of pin 29 projecting from the rear wall 28 of the insert pocket 16 and the recess 49 in the one or more side surfaces 36 of the cutting insert 30 constitutes an anti-rotation mechanism of the invention that reduces or eliminates rocking of the cutting insert 30 when mounted in the insert pocket 16. In the illustrated embodiment, a pin 29 that is circular in shape and a recess 49 with a corresponding circular shape is shown. However, it will be appreciated that the invention is not limited by the specific shape of the pin 29 and the recess 49, so long as the pin 29 and the recess 49 have complimentary shapes to enable a portion of the pin 29 to be received in the recess 49. For example, the pin 29 and the recess 49 can be polygonal in shape, such as a triangle, square, rectangle, pentagon, hexagon, heptagon, octagon, and the like.

In the illustrated embodiment, there is a one-to-one correlation between the number of side surfaces 36 and the number of recesses 49. Thus, the octagon cutting insert 30 has eight (8) side surfaces 36 and eight (8) recesses 49. In this manner, the cutting insert 30 can be indexed a total of sixteen (16) times (i.e. eight (8) times when the top surface 32 is presented to the workpiece and eight (8) times when the bottom surface 34 is presented to the workpiece). However, it will be appreciated that the invention is not limited by the number of side surfaces 36 and recesses 49. For example, the principles of the invention can be practiced with a cutting insert with six (6) side surfaces 36 and six (6) recesses 49. In addition, it will be appreciated that the invention is not limited by a one-to-one correlation between the number of side surfaces 36 and the number of recesses 49. For example, the cutting insert 30 may have eight (8) side surfaces 36, but only four (4) recesses 49 such that the cutting insert 30 can be indexed a total of only eight (8) times (i.e. four (4) times when the top surface 32 is presented to the workpiece and four (4) times when the bottom surface 34 is presented to the workpiece).

As shown in FIG. 7, a central axis, A, of each recess 49 is centrally located in the corresponding side surface 36 of the cutting insert 30. In other words, the central axis, A, of each recess 49 is equidistant from the cutting edges 40, 42 formed by the intersection between the corresponding side surface 36 and the top and bottom surface 32, 34, respectively. In this manner, both the top and bottom surfaces 32, 34 of the cutting insert 30 can be presented to the workpiece. In addition, the central axis, A, of each recess 49 is equidistant to the corners 41, 43 such that the cutting edges 40 formed at the intersection between the top surface 32 and each side surface 36 can be presented to the workpiece, as well as the cutting edges 42 formed at the intersection between the bottom surface 34 and each side surface 36.

The cutting insert 30 may also include a central bore (not shown) extending entirely through the cutting insert 30 from the top surface 32 to the bottom surface 34 for mounting the cutting insert 30 to a cutting tool using a mounting screw (not shown). In the illustrated, the central bore is omitted because the cutting insert 30 is mounted to the tool body 12 using the clamping element 50.

Referring back to FIG. 2, the clamping element 50 includes an arcuate-shaped top surface 52, a planar bottom surface 54, and a pair of opposing side surfaces 56, 58 (only side surface 56 can be clearly seen in FIG. 2). The clamping element 50 also includes a bore 60 extending from the side surface 56 to the side surface 58 for receiving a clamping screw 62 to mount the clamping element assembly 20 to the tool body 12 of the milling cutter 10.

It is noted that the distance between the opposing side surfaces 56, 58 of the clamping element 50 is smaller than the distance between the opposing side surfaces 36 of the cutting insert 30. In this manner, the cutting edges 40, 42 of the cutting insert 30 will be presented to the workpiece (not shown) when the cutting insert 30 is mounted in the insert pocket 16 of the tool body 12, as shown in FIG. 1.

For the purposes of this discussion, a cutting insert having a geometry identified as an octagon is presented. However, it should be realized that the configuration of this invention should not be limited to a octagon and that other geometric shapes with a large number of side surfaces may be substituted, for example, a hexagon, a heptagon, a decagon, and the like.

As described above, an anti-rotation mechanism for preventing the movement of the cutting insert when mounted in the insert pocket of milling cutter comprises an indexable cutting insert having at least one recess in a side surface and a pin protruding from a radially-inward rear wall of an insert pocket that is partially received in the recess of the cutting insert. The recess can be formed in the side surface of the cutting insert by side actuation pressing or by machining (i.e., an additional step to the periphery grinding operation. It should be appreciated that the principles of the invention can be applied when the insert pocket includes a recess that is capable of receiving a portion of a pin protruding from a cutting insert.

The patents and publications referred to herein are hereby incorporated by reference.

Having described presently preferred embodiments the invention may be otherwise embodied within the scope of the appended claims.

PARTS LIST
10 cutting tool (milling cutter)
12 body
13 central, longitudinal axis
14 cutting end
16 insert pocket
17 clamping element pocket
18 mounting end
20 clamping element assembly
22 bottom support wall
24 first side support wall
26 second side support wall
28 radially-inward rear wall
28a aperture
29 pin
30 cutting insert
31 polygonal body
32 top surface
34 bottom surface
36 side surface
38 angle
39 plane
40 cutting edge
41 corner
42 cutting edge
43 corner
44 rake surface
46 seating surface
48 seating surface
49 recess
50 clamping element
52 arcuate top surface
54 bottom surface
56 side surface
58 side surface
CL central axis (cutting insert)
A central axis (recess)