Cutting tool and tool head

The present invention relates to a tool head preferably for milling. The tool head is connectable to a toolholder. The tool head includes a cutting portion and a mounting portion. The mounting portion includes an axial stop surface and a radial stop surface. Dimensions and tolerances of the axial stop surface and the radial stop surface are selected such that the axial stop surface will abut an axial stop on the toolholder to prevent axial movement of the toolholder relative to the tool head beyond the axial stop surface and the radial stop surface will be disposed proximate a radial stop of the toolholder to limit radial movement of the tool head relative to the toolholder when an integral fastening portion of the tool head and an integral fastening portion of the toolholder are fastened directly to one another and the axial stop surface and the axial stop abut.

BACKGROUND AND SUMMARY

It is often extremely important in operations such as machining of metal or other workpieces that the location of a cutting edge of a cutting tool be precisely controlled and controllable. Complex machinery is provided to mill, drill, bore, or otherwise perform shaping operations on workpieces by precisely controlling the location of a cutting tool relative to the workpiece. Cutting tools often include replaceable inserts or cutting heads that are attached to permanent toolholders such as shanks that are moved relative to the workpiece.

The accuracy of the mounting of the cutting inserts or heads relative to the toolholder is a factor in the accuracy of the operation to be performed on the workpiece. In the case, for example, of a rotating tool, an insert or tool head that is displaced axially relative to a rotating shank to which it is attached can damage the workpiece and may necessitate the rejection of an expensive part. It is therefore desirable to minimize the possibility of movement of an insert or tool head relative to a toolholder.

According to an aspect of the present invention, a cutting tool includes a toolholder including an end portion, the end portion including an axial stop, and a radial stop. The cutting tool also includes a replaceable tool head having an axial stop surface, and a radial stop surface. The end portion is at least partially receivable in an internal opening in the tool head up to a position at which the axial stop abuts the axial stop surface to prevent axial movement of the toolholder relative to the tool head beyond the axial stop surface. The radial stop surface and the radial stop are disposed proximate one another to limit radial movement of the tool head relative to the toolholder when an integral fastening portion of the tool head and an integral fastening portion of the toolholder are fastened directly to one another and the axial stop surface and the axial stop abut.

According to another aspect of the present invention, a tool head includes a cutting portion and a mounting portion, the mounting portion including an axial stop surface, and a radial stop surface. Dimensions and tolerances of the axial stop surface and the radial stop surface are selected such that the axial stop surface will abut an axial stop on a toolholder to prevent axial movement of the toolholder relative to the tool head beyond the axial stop surface and the radial stop surface will be disposed proximate a radial stop of the toolholder to limit radial movement of the tool head relative to the toolholder when an integral fastening portion of the tool head and an integral fastening portion of the toolholder are fastened directly to one another and the axial stop surface and the axial stop abut.

DETAILED DESCRIPTION

A tool21according to an embodiment of the present invention is shown inFIGS. 1-3. The tool21includes a toolholder in the form of a shank23including an end portion25. The end portion25includes an axial stop27, and a radial stop29. The shank23shown here is a circular cylinder, however, the shank may have other shapes as desired, such as, for example, a hexagonal shape, a splined shape, etc. The present invention has application to all manner of tools to which replaceable cutting heads or inserts are attachable, such as milling, drilling, boring, turning, and similar tools. The embodiment illustrated inFIGS. 1-3is a rotating tool.

The tool21also includes a replaceable insert or tool head31having an axial stop surface33, and a radial stop surface35. In the embodiment ofFIGS. 1-3, the end portion25is at least partially receivable in an internal opening37in the tool head31up to a position at which the axial stop27abuts the axial stop surface33. When the axial stop27and the axial stop surface33abut, the radial stop surface35and the radial stop29are disposed proximate one another to permit limited radial movement of the tool head31relative to the shank23. At the same time, fastening portions, such as threaded members61and63of the toolholder23and the tool head31can be fastened directly to one another. The fastening portions can be integral with the toolholder23and tool head31to facilitate proper orientation of the tool head relative to the toolholder. By providing fastening portions that are integral with the toolholder23and tool head31, the number of components forming the tool and the complexity of the tool can be minimized, and the number of variables that can result in inaccurate positioning of the tool head relative to the toolholder can be minimized. Ordinarily, the radial stop surface35and the radial stop29will be close to one another but sufficiently distant to one another until the axial stop27and the axial stop surface33abut such that movement of the axial stop and the axial stop surface relative to one another to an abutting position will not be impeded by the radial stop and the radial stop surface. The closer the radial stop surface35and the radial stop29are when the axial stop surface33and the axial stop27abut, the better will be the ability of the radial stop surface and the radial stop to limit radial movement of the tool head31relative to the shank23. It will be noted that other embodiments of the invention may not include having, e.g., a portion of a toolholder received in a portion of an insert or cutting head as in the embodiments ofFIGS. 1-3. The tool head31may be, but is not necessarily, made out of a material such as cemented carbide that may be harder than the material, such as high speed steel, from which the shank23may be made.

Ordinarily, dimensions and dimensional tolerances of the radial stop surface35and the radial stop29will be selected such that they will not contact or will barely contact when there is no load on the shank23and tool head31so that the contact between the shank23and the tool head31will not be overdetermined. However, those dimensions and tolerances are further selected such that the radial stop29and the radial stop surface35are located close enough to one another that the radial stop will contact the radial stop surface upon application of some non-zero load to the tool head31perpendicular to its axis A. In this way, unintended radial movement of the tool head31relative to the shank23during operation can be controlled.

The tool head31will ordinarily include cutting edges39or pockets (not shown) for mounting inserts with cutting edges and may be fluted along part or all of its length.

In the embodiment shown inFIGS. 1-3, the axial stop27includes a substantially flat surface43substantially perpendicular to an axis B of the shank. The surface43need not, however, be perpendicular and may be partially or entirely at an angle to the perpendicular, and may be curved or otherwise non-flat. In the embodiment of the invention shown inFIGS. 1-3, the radial stop29includes a surface45for abutment against the radial stop surface35of the tool head31that defines a non-zero angle with the axis B of the shank23. In this embodiment, the surface45faces toward the axis B of the shank23.

In the embodiment ofFIGS. 1-3, the radial stop29is part of an annular groove47around the axis B of the shank23, and the radial stop surface35is part of an annular protrusion49around the axis A of the tool head31. If desired, the radial stop may be part of an annular protrusion and the radial stop a part of an annular groove. When the axial stop27and the axial stop surface33abut, an end51of the annular protrusion49and a bottom53of the annular groove47are separated by a non-zero distance to ensure that the axial stop27will abut the axial stop surface33. Annular grooves and recesses are useful in embodiments such as shown inFIGS. 1-3wherein the tool head31is screwed onto the shank23, however, in other embodiments where the tool head and the shank are connected in some other way, shapes other than annular grooves and recesses may be used to form part of the radial stop and radial stop surfaces.

The tool head31can include at least one tool head passage55and the shank23can include at least one shank passage57. As seen inFIG. 1, the at least one tool head passage55and the at least one shank passage57can communicate when the tool head31is mounted relative to the shank23. The communicating passages can be used, for example, to supply lubricant or coolant to the cutting edges39.

In the embodiment ofFIGS. 1-3, the external portion41of the tool head31proximate the axial stop surface33is circularly cylindrical. The external portion41may be useful as a surface for a wrench or other tool to contact during mounting of the tool head31relative to the shank23. If an external portion is provided, it may be any suitable shape, such as hexagonal or splined, as desired. An external surface portion59of the shank23may be circularly cylindrical as shown inFIGS. 2-3, or any other desired shape, such as hexagonal, splined, etc.

In the embodiment ofFIGS. 1-3, the end portion25includes an integral fastening portion in the form of an externally threaded portion61and the internal opening37includes an integral fastening portion in the form of an internally threaded portion63adapted to engage with the externally threaded portion. In this embodiment, as seen in, e.g.,FIG. 1, the radial stop29and the radial stop surface35may be considered to merge into the axial stop27and the axial stop surface33, respectively. For purposes of describing the relative positions of these surfaces, however, because the substantial majority of the radial stop29and the radial stop surface35are disposed below the axial stop27and the axial stop surface33, respectively, on the shank23, the axial stop27shall be considered to be disposed between the externally threaded portion61and the radial stop29and, on the tool head31, the axial stop surface33shall be considered to be disposed between the internally threaded portion63and the radial stop surface35. When the tool21is a rotating tool, the internally threaded portion63and the externally threaded portion61will ordinarily be threaded such that, when the rotating tool is rotated in an intended working direction, the tool head31is tightened on the shank23. To ensure that the threads on the externally threaded portion61and the internally threaded portion63do not function as radial stops and radial stop surfaces, an average distance between the radial stop29and the radial stop surface35will ordinarily be less than an average distance between the externally threaded portion and the internally threaded portion at major and minor thread diameters thereof.

Thus, according to an embodiment of the invention seen inFIGS. 1-3, the cutting tool21includes a toolholder23, the end portion25of the toolholder including the axial stop27and the radial stop29. The axial stop27can include a surface substantially perpendicular43to an axis B of the toolholder23. The radial stop29can include a surface45facing toward the axis B of the toolholder23.

Additionally, a tool head31according to an embodiment of the invention seen inFIGS. 1-3, comprises a cutting portion and a mounting portion. The mounting portion includes an axial stop surface33and a radial stop surface35. The radial stop surface35includes a surface45facing away from an axis A of the tool head31. Dimensions and tolerances of the axial stop surface and the radial stop surface are selected such that the axial stop surface will abut the axial stop27on the toolholder23to prevent axial movement of the toolholder relative to the tool head31beyond the axial stop surface33and the radial stop surface35will be disposed proximate a radial stop29of the toolholder23to limit radial movement of the tool head31relative to the toolholder when an integral fastening portion63of the tool head and an integral fastening portion61of the toolholder23are fastened directly to one another and the axial stop surface and the axial stop abut. When the axial stop27and the axial stop surface33abut, an end51of the annular protrusion49and a bottom53of the annular groove47are separated by a non-zero distance.

The radial stop29can be part of an annular groove47around the axis B of the toolholder23. The radial stop surface35can be part of an annular protrusion49around the axis A of the tool head31. The axial stop surface33can be disposed between the internally threaded portion63and the radial stop surface35. Of course, if desired, the radial stop can be a protrusion and the radial stop surface can be a groove.

The tool head31can include at least one tool head passage55and the toolholder23includes at least one toolholder passage57. The at least one tool head passage55and the at least one toolholder passage57can communicate when the tool head31is mounted relative to the shank23.

In the embodiment ofFIGS. 1-3, the tool head31includes an internal opening37, and the internal opening37includes an internally threaded portion63forming at least part of the integral fastening portion and is adapted to engage with an externally threaded portion61forming at least part of the integral fastening portion of the toolholder23. It will be appreciated, of course, that the toolholder can include the internal opening with the internal threads and the tool head can include the externally threaded portion.

FIG. 4shows another embodiment of a tool121according to the present invention. The tool121can be the same as the tool21described in connection withFIGS. 1-3in all respects save that no annular groove or recess arrangement is provided. In the tool121, the radial stop129may include a surface145substantially parallel to or slightly inclined relative to an axis B of the shank123and the radial stopping surface135may include a surface143similarly substantially parallel to or slightly inclined relative to an axis A of the tool head131. In this embodiment, the radial stop129includes a surface145facing away from the axis B of the shank123and the radial stop surface135includes a surface143facing toward the axis A of the tool head131.

In an embodiment of the tool ofFIG. 4having a threaded connection, the radial stop129can include an unthreaded surface145disposed at an end165of a fastening portion in the form of an externally threaded portion161and the radial stop surface135can include an unthreaded surface disposed at an end167of a fastening portion in the form of an internally threaded portion163of the tool head131. The fastening portions can be integral with the toolholder123and the tool head131to facilitate proper orientation of the tool head relative to the toolholder. In the embodiment ofFIG. 4, the radial stop129is disposed between the externally threaded portion161and the axial stop127of the shank, and the radial stop surface135is disposed between the internally threaded portion163and the axial stop surface133of the tool head. If desired, the radial stop and radial stop surface may be disposed at ends of the externally and internally threaded portions opposite the axial stop and axial stop surface.

The following description with respect to the tool head31ofFIGS. 1-3will generally apply as well to the tool head131ofFIG. 4, except where otherwise noted. The tool head31includes a cutting portion and a mounting portion. The mounting portion includes the axial stop surface33, and the radial stop surface35. Dimensions and tolerances of the axial stop surface33and the radial stop surface35are selected such that the axial stop surface will abut the axial stop27on the toolholder23to prevent axial movement of the toolholder relative to the tool head beyond the axial stop surface and the radial stop surface35will be disposed proximate the radial stop29of the toolholder to limit radial movement of the tool head31relative to the toolholder or shank23when the axial stop surface and the axial stop abut.

In the tool head31ofFIGS. 1-3, the axial stop surface33includes a surface substantially perpendicular to the axis A of the tool head. However, the axial stop surface need not be perpendicular in whole or in part to the axis of the tool head. InFIGS. 1-3, the radial stop surface35includes a surface45that defines a non-zero angle with the axis A of the tool head31. Here, the radial stop surface35includes a surface45generally facing away from the axis A of the tool head31. InFIGS. 1-3, the radial stop surface35is part of an annular protrusion49around the axis A of the tool head, although an annular recess or some other suitable shape may be provided, instead.

The tool head31can include the internal opening37. The internal opening37can include the internally threaded portion63adapted to engage with the externally threaded portion61of the toolholder or shank23. The axial stop surface33can be disposed between the internally threaded portion63and the radial stop surface35.

In the embodiment ofFIG. 4, the radial stop surface135can include a surface substantially parallel to or forming a slight angle relative to the axis A of the tool head131. The radial stop surface135includes a surface facing toward the axis A of the tool head131.

The tool head131can include an internal opening137and the radial stop surface135can form at least part of the internal opening. The radial stop surface135can include an unthreaded surface disposed at the end167of the externally threaded portion161disposed between the internally threaded portion and the axial stop surface133or at an end of the externally threaded portion opposite the axial stop surface.

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.

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.