Patent Application
20070286692
The features and advantages of the present invention are well understood by reading the following detailed description in conjunction with the drawings in which like numerals indicate similar elements and in which:
A cutting tool 21 according to an embodiment of the present invention is shown in
The cutting tool 21 also includes a cutting insert 29 receivable in an insert-receiving pocket 25. As seen in
The cutting tool 21 also includes a clamp 39 having a clamp surface 41 as seen in
The clamping surface 37 may be part of a larger surface that is not a non-circular, substantially elliptical cone, however, the clamping surface itself shall be considered a portion of any larger surface where the portion is intended to be contacted by the clamp surface 41, and where the clamping surface has the form of a non-circular, substantially elliptical cone or truncated cone. For purposes of the present application, except where otherwise indicated, an “elliptical cone” shall be defined to cover shapes that are elliptical as well as other rounded shapes, such as ovals, that are not ellipses in the mathematical sense, and shall be defined as excluding shapes that are circular, even though, technically, a circle is a form of ellipse. The precise form of the surfaces is not as important as the possibility of having at least two discrete points of contact between the clamping surface 37 and the (usually circular) clamp surface 41. The at least two contact points 43 and 45 reduce the possibility of movement of the insert 29 relative to the clamp 39 as compared to clamping arrangements having only a single point of contact.
In the illustrated embodiments, the clamping hole 35 extends through the insert body 31, and the insert-receiving pocket 25 includes an internally threaded hole 47 for receiving a threaded clamping screw 49. A head 51 of the clamping screw 49, more specifically, the underside of the head of the clamping screw, defines the clamp surface 41. The underside of the clamping screw head 51 can have any suitable shape, but will ordinarily be in the form of a substantially truncated cone shape, a substantially spherical shape (shown in phantom in
An axis ATH of the internally threaded hole 25 will ordinarily be substantially parallel and aligned with an axis ACH of the clamping hole 35 when the at least one side abutment surface 27 and the at least one insert supporting surface 33 are secured in the contacting relationship as seen in
The clamp 39 is adapted to move to a clamping position relative to the toolholder 23 and the cutting insert 29 in which clamping forces at the two contact points 43 and 45 urge the at least one insert supporting surface 33 of the cutting insert against the at least one insert abutment surface 27 of the insert-receiving pocket 25. Particularly for polygonal inserts, as seen in
The at least one insert abutment surface 27 and the at least one insert supporting surface 33 typically define non-zero angles with an axis ACH of the clamping hole 35 when the at least one side abutment surface and the at least one insert supporting surface are secured in a contacting relationship. The angles formed by the abutment surface 27 and the insert supporting surface 33 are typically the same as each other, or close to the same as each other, such that, as the (usually circular) clamp surface 41 of the clamp 39 moves downward to the clamping position along the generally conical elliptical surface of the clamping surface 37 of the clamping hole 35, a camming action of the contact points 43 and 45 urges the insert supporting surface(s) toward and into contact with respective abutment surface(s). It will be appreciated, however, that the present invention has application with inserts with insert supporting surfaces that are parallel to the axis of the clamping hole 35, such as where the insert is indexable by being turned upside down.
For example, if the angle of the insert supporting surface 33 with the axis ACH of the clamping hole 35 is less than the angle of the abutment surface 27 with the axis ACH, and if the insert supporting surface extends above the abutment surface, it is possible to predict with substantial accuracy that contact between the insert supporting surface 33 and the abutment surface 27 will occur at the top of the abutment surface, thereby facilitating ensuring that the cutting edge(s) of the insert 29 will be properly located relative to the toolholder 23. As seen in
To further facilitate ensuring proper seating of the insert 29 relative to the toolholder 25, as disclosed in U.S. Pat. No. 5,421,679, which is incorporated by reference, at least one of the at least one of the insert supporting surface 33 and the at least one the side abutment surface 25 can include a recess 53 (shown in phantom in
As seen in
While the insert 29 has been described in connection with embodiments wherein the clamping hole 39 extends entirely through the insert body 33, the clamping hole can be formed to extend only partially through the insert body. Instead of securing the insert 29 with a clamp 39 in the form of a screw or bolt, the clamp can be in some other known form, such as in the form of a clamping arm (not shown) that is secured to or integral with the toolholder and secures an insert relative to a pocket or recess for the insert in the toolholder. Embodiments of toolholders with various forms of clamping arms are disclosed in, for example, U.S. Pat. Nos. 6,702,528, 6,244,790, and 6,168,357, which are incorporated by reference.
The cutting insert 29 can have a clamping hole 35 that, in addition to the clamping surface 39 having the form of an elliptical cone, can include a substantially cylindrical surface 55. The substantially cylindrical surface 55 will ordinarily be disposed vertically above the clamping surface 39 and may be useful for, among other things, ensuring that the head 51 of the screw 49 is disposed below a top end of the clamping hole 35. The clamping surface 39 and the cylindrical surface 55 will ordinarily intersect, however, some other surface, such as a curved or semi-spherical surface may be disposed between the surfaces.
The clamping surface 39 ordinarily has two ends, i.e., an upper end 57 and a lower end 59. The cylindrical surface 55 can be disposed proximate one end, e.g., the upper end 57, of the clamping surface 39, and the end 59 of the clamping surface opposite the cylindrical surface, i.e., the lower end 59, can intersect with a second substantially cylindrical surface 61.
In the present application, the use of terms such as “including” is open-ended and is intended to have the same meaning as terms such as “comprising” and not preclude the presence of other structure, material, or acts. Similarly, though the use of terms such as “can” or “may” is intended to be open-ended and to reflect that structure, material, or acts are not necessary, the failure to use such terms is not intended to reflect that structure, material, or acts are essential. To the extent that structure, material, or acts are presently considered to be essential, they are identified as such.
The disclosures in Swedish patent application No. 0601152-2, from which this application claims priority are incorporated herein by reference.
While this invention has been illustrated and described in accordance with a preferred embodiment, it is recognized that variations and changes may be made therein without departing from the invention as set forth in the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 0601152-2 | May 2006 | SE | national |
