EP0715554A1

EP0715554A1 - Milling cutter with insert adapter

Info

Publication number: EP0715554A1
Application number: EP94921489A
Authority: EP
Inventors: Robert N. Mitchell
Original assignee: Kennametal Inc
Current assignee: Kennametal Inc
Priority date: 1993-08-25
Filing date: 1994-07-11
Publication date: 1996-06-12
Also published as: CA2168661A1; DE715554T1; AU7220094A; KR960703697A; ES2088841T1; BR9407516A; WO1995005913A1; JPH08508942A; CN1129415A

Abstract

A milling cutter (10) is capable of receiving replaceable cutting inserts (70) of different shapes and sizes. The milling cutter (10) comprises a generally cylindrical cutter body (12). A plurality of insert seats (24) are formed about the outer periphery of the cutter body (12). Each insert seat (24) is adapted to receive either a cutting insert (70) of a first predetermined size and shape or an adapter (40). The adapter (40) includes a second insert seat (46) for receiving a cutting insert (70a, b) of a second predetermined shape and size. Clamping means (60) are mounted on the cutter body (12) and are operable to clamp the cutting insert (70) of said first predetermined size and shape in the insert seat (24) of the cutter body (12), or to clamp a cutting insert (70a, b) of a second predetermined size and shape in the insert seat of the adapter (40).

Description

MILLING CUTTER WITH INSERT ADAPTER

FIELD OF THE INVENTION The present invention relates generally to milling cutters having replaceable inserts, and more particularly to a milling cutter having replaceable adapters for receiving inserts of different shapes and sizes.

BACKGROUND OF THE INVENTION A typical milling insert comprises a cylindrical body having a plurality of slots or recesses formed in its outer periphery. Each slot is formed with an insert seat which holds a replaceable cutting insert. The cutting insert has one or more cutting edges which are adapted to engage a work piece during the milling operation. When the cutting insert becomes worn or damaged, the insert can be replaced by a new insert.

This type of milling insert is limited in that it can only be used to receive and hold a cutting insert of a predetermined size and shape. Thus, a separate cutter body must be kept available for each different shape or size cutting insert which may be needed. Because the cutter body itself is the most expensive component of the milling cutter, maintaining a large inventory of different cutter bodies for different types of inserts is expensive.

Additionally, the surfaces surrounding the insert seat in the cutter body are sometimes subject to damage during the milling operation. Damage to the insert seat usually occurs when the insert breaks. If these surfaces become damaged, replacement of the entire cutter body may be required.

From the past, it is known to use replaceable cartridges or tool holders for mounting the cutting inserts to a milling cutter. The insert seat for holding the cutting insert is formed in the cartridge or tool holder. Milling cutters with replaceable cartridges are shown in the patents to Dunklau, U.S. Patent No. 5,033,916; Dickinson, U.S. Patent No.

4,566,826; Mitchell, U.S. Patent No. 5,102,268; and Lovendahl, U.S. Patent No. 3,739,442. These types of milling cutters require the use of a replaceable cartridge and cutting inserts cannot be mounted to the cutter body without such cartridges.

SUMMARY AND OBJECTS OF THE INVENTION The present invention is a milling cutter which is capable of receiving and holding multiple shapes and sizes of cutting inserts. The milling cutter includes a generally cylindrical cutter body having a plurality of slots formed in its outer periphery. Each slot includes a bottom and a pair of side walls. A first seat is formed in one of the side walls of each slot for receiving a cutting insert of a first predetermined shape and size. An adapter may also be received into the first insert seat in the cutter body. The adapter includes a second insert seat which receives a cutting insert of a second predetermined shape and size. A wedge clamp is disposed in the slot of the cutter body for clamping the cutting inserts in their respective pockets.

The adapter enables the cutter body to be used with a plurality of inserts of different shapes and sizes. The milling cutter can be converted for use with different styles of inserts by simply changing the adapters. Further, the adapters provide protection for the cutter body when the cutting insert breaks, thereby possibly avoiding damage to the cutter body.

Based on the foregoing, it is an object of the present invention to provide a milling cutter which is capable of receiving and holding cutting inserts of many different shapes and sizes.

Another object of the present invention is to provide an adapter for a milling cutter which enables the cutter body to accept, in addition to a first cutting insert of a first predetermined shape and size, at least one other differently shaped or sized cutting insert.

Still another object of the present invention is to provide an adapter for a milling cutter which minimizes the risk of damage to the milling cutter as a result of tool breakage.

Yet another object of the present invention is to provide an adapter for a milling cutter which can be replaced relatively easily and which will accurately position the cutting insert.

Other objects and advantages of the present invention will become apparent and obvious from a study of the following description and the accompanying drawings which are merely illustrative of such invention.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of the milling cutter of the present invention.

Figure 2 is a side elevation view of the milling cutter.

Figure 3 is a detail perspective of the milling cutter showing the insert seat in the cutter body.

Figure 4 is a section view through the slot of the cutter body.

Figures 5-8 are perspective views illustrating various types of adapters. DETAILED DESCRIPTION OF THE INVENTION Referring now to the drawings, and particularly to Fig. 1, the milling cutter of the present invention is shown therein and indicated generally by the numeral 10. The milling cutter 10 comprises a generally cylindrical cutter body 12 and a plurality of adapters 40 mounted on the periphery of the cutter body 12 for receiving and holding cutting inserts 70. The cutter body 12 has an axial opening 14 for mounting the cutter body 12 on a spindle adapter (not shown) . The spindle adapter typically includes a tapered rear portion that fits into a tapered cavity in the spindle of a milling machine. The cutter body is typically held on the spindle adapter by a large screw (not shown) which threads into the end of the spindle adapter. Since spindle adapters are well known to those skilled in the art, further description of the same is omitted. The cutter body 12 is formed with a plurality of circumferentially-spaced slots 16 (Figure 2) disposed about the outer periphery of the cutter body 12. Each slot 16 has a flat bottom 18 and a pair of side walls 20 and 22. The side walls 20 and 22 diverge slightly from one another from the bottom 18 of the slot 16. Each slot 16 is angled in a positive direction in relation to the axis of the cutter body, and in a negative direction in relation to a radius of the cutter body. This is conventional in the milling cutter art. But expressed in another way, the walls 20, 22, and 26 of an insert seat 24 are angled such that the upper leading edge 78 of a respective cutting insert 70, when mounted within the insert seat 24, is angled towards the direction of rotation of the cutter body 12. This essentially means that the top face 72 of the cutting insert 70 lies in a plane that is slightly inclined upwardly and forwardly toward the direction of travel of the cutter body 12. This, of course, means that the upper cutting edge 78 (Fig. 4) of the cutting insert 70 leads the lower base of the cutting insert 70 when mounted. This, in conventional fashion, produces what is known in the art as a positive axial rake and negative radial rake which in turn produces what is known as shear-angled geometry.

An insert seat indicated generally by the numeral 24 (Fig. 3) is recessed within the side wall 20 in each slot 16. The insert seat 24 includes a back wall 26 and a pair of side walls 28 and 30. The back wall 26 is parallel to the side wall 20 of slot 16 and includes a threaded opening 36 for securing the adaptor as described more fully below. The side walls 28 and 30 extend in generally perpendicular fashion from the back wall 26 and are disposed at approximately right angles relative to one another. The side walls 28 and 30 each include a bevel 32 adjacent the intersection with the side wall 20 of slot 16. A relief 34 is also formed at the intersection of each side wall 28 and 30 with the back wall 26.

Each insert seat 24 in the cutter body 12 is adapted to receive a cutting insert 70 of a first predetermined shape and size. The cutting insert 70 typically includes a top face 72, a bottom face 74 and side walls 76 extending between the top and bottom faces 72 and 74. The intersection of the side walls 76 with the top face 72 defines one or more cutting edges 78. Typically, the side walls 76 are inclined to form an acute angle with the plane of the top face 72.

A cutting insert 70 can be mounted directly into the insert seat 24 with the bottom surface 74 of the cutting insert 70 disposed against the back wall 26 of the insert seat 24. In this mode of application, the cutting insert 70 is square in shape and has four side walls 76. The insert seat 24 has two side walls 28, 30 which engage two of the side walls 76 in the cutting insert 70. The cutting insert 70 can be indexed to present different cutting edges 78 to the work piece when other cutting edges 78 become worn. Thus, it is appreciated that a cutting insert 70 can be mounted directly into the insert seat 24 without an adapter being required.

In order to accommodate cutting inserts 70 of different shapes and sizes, an adapter 40 can be mounted in the insert seat 24. Each adapter includes a bottom surface 42 and a top surface 44. The top surface 44 includes a second insert seat 46 for receiving a cutting insert 70 of a different size and/or shape than the insert seat 24 in the cutter body 12. The insert seat 46 includes an insert support surface 48 and one or more side walls 50. A through- bore 52 extends from the support surface 48 through the adapter 40 to the bottom surface 42. The through-bore 52 aligns with the threaded opening 36 in the cutter body 12. A securing screw 54 passes through the through-bore 52 and is threadably engaged in the threaded opening 36 of the cutter body to secure the adapter 40 within the insert seat 24 of the cutter body 12.

The cutting insert 70 is secured in the adapter 40 by a wedge clamping means 60. The wedge clamping means 60 in the disclosed embodiment comprises a wedge 62 and a wedge actuator 64. The wedge 62 includes first and second wedge surfaces 62a and 62b. Wedge surface 62a is adapted to engage the wall 22 of slot 16 which is opposite the insert seat 24. Wedge surface 62b is adapted to engage the top face 72 of the cutting insert 70.

The wedge actuator 64 is a differential screw having right-hand threads at first end 64a and left- hand threads at a second end 64b. The first end 64a threadably engages with a first screw hole 66 in the bottom 18 of slot 16. The second end 64b of the screw 64 is threadably engaged with a second screw hole 68 in the wedge 62. The second end 64b has a socket which is engageable for rotation. When the actuator 64 is turned in a first direction, the wedge 62 is moved downwardly in the slot 16 to secure the cutting insert 70 in the adapter 40. The wedge 62 can also be used to clamp a cutting insert 70 of a first predetermined shape and size directly in the insert seat 24 of the cutter body 12. When the screw 64 is turned in the opposite direction, the wedge is moved upwardly in the slot 16 thereby releasing the cutting insert 70.

In use, the milling cutter can be used with an insert of a first predetermined shape and size as shown in Fig. 5. The cutting insert 70 of Fig. 5 is sized appropriately to fit in the insert seat 24 of the cutter body 12. In normal use, a shim S, having a top surface 100 and a back 102, is placed between the cutting insert 70 and the support surface 26 of the insert seat 24. The shim S includes a threaded bore 53. Shim S can be securely stationed in the insert seat 24 by threading screw 54 through the threaded bore 53 and into threaded opening 36. The bottom face 74 of the cutting insert 70 abuts against the top surface of the shim S. Two of the side surfaces 76 abut respectively against the bevel 32 of the insert seat

24. The cutting insert 70 of Fig. 5 is secured in the insert seat 24 by the wedge clamp 62.

The adapter 40 allows the cutter body 12 to also be used with many other shapes and sizes of cutting insert 70 by various configurations of adapters 40 as shown in Figs. 6-8. Figure 6 illustrates an adapter for receiving a square cutting insert 70. Figure 7 shows an adapter for an octagonal style insert. Figure 8 shows an adapter for a circular-style insert.

Referring now to Fig. 6, the adapter 40 (shown also in Fig. 3) is adapted to receive and support the square cutting insert 70. Adapter 40 includes an insert seat 46 having a pair of inclined side walls 50. The cutting insert 70 mounts within the insert seat 46 with the back face 74 of the cutting insert 70 being placed against the support surface 48. Two of the side walls 76 of the cutting insert 70 are placed against the side walls 50 of the adapter 40. The cutting inset 70 is secured by the wedge clamp 62 (Fig. 3). In Fig. 7, another variation of the adapter is shown and indicated generally by 40a. Adapter 40a shown in Fig. 7 includes an insert seat 46a having a single side wall 50a. More particularly, the structure of the adapter 48 shown in Fig. 7 generally corresponds to the adapter 40 shown in Figs. 3 and 6. In this regard, it should be noted that the adapter 40a includes a bottom surface 42a and a top surface 44a. An octagonal cutting insert 70a is shown being used with the adapter 40a. The octagonal cutting insert 70a mounts in the insert seat 46a with the bottom face 74a being placed against the support surface 48a. One of the side walls 76a is placed against the side wall 50a of the adapter 40a.

Figure 8 shows another adapter design. The adapter shown in Fig. 8 is referred to by 40b and is adapted to receive and hold a round insert indicated generally by the numeral 70b.- Round insert 70b, as shown in Fig. 8, includes a front face 72b, a back face 74b, and a round or curved side 76b. Adapter 40b includes an insert seat 46b that includes a bottom surface 42b and a top surface 44b. The insert seat 46b is formed by an insert support surface 48b and a pair of side walls 50b. A threaded opening 52b is formed in the adapter 40b for receiving the threaded screw 54. In use, the circular insert 70b mounts within the insert seat 46b in such a fashion that the side walls 76b of the round inserts 70b engage each of the side walls 50b in tangential fashion.

The embodiments of the adapter 40 shown in Figs. 6-8 are only representative embodiments of the adapter. It is to be understood that the exact configuration of the adapter will be dependent on the geometry of the cutting insert to be mounted therein. Further, it should be understood that in many cases, the adapter 40 can be designed to accommodate more than one style insert.

Based on the foregoing, it is apparent that the milling cutter of the present invention provides a convenient method for mounting cutting inserts of different shapes and sizes on a cutter body. This goal is accomplished in the present invention by providing an adapter which fits into the insert seat of the cutter body. The adapter has a second insert seat which accepts a cutting insert of a second predetermined size and shape. Since the cutter body of the present invention can be used with many different styles of inserts, the expense of maintaining a large inventory of cutter bodies for different inserts is eliminated.

The present invention may, of course, be carried out in other specific ways than those herein set forth without departing from the spirit and essential characteristics of the invention. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.

Claims

WHAT IS CLAIMED IS;

1. A milling cutter capable of receiving replaceable cutting inserts of different shapes and sizes comprising: (a) a generally cylindrical cutter body;

(b) at least one slot formed in an outer periphery of the cutter body, said slot having a bottom and a pair of side walls;

(c) a first insert seat formed in the slot for receiving a first cutting insert of a first predetermined shape and size or for receiving an adapter;

(d) an adapter insertable into said first insert seat in said cutter body and including a second insert seat for receiving a second cutting insert of a second predetermined shape and size;

(e) securing means for securing said adapter in said first seat in said cutter body; and

(f) a clamp for clamping said first cutting insert in the first insert seat and for clamping the second cutting insert in said second seat in said adapter.

2. The milling cutter of claim 1 wherein said clamping means comprises a wedge and a wedge actuator.

3. The milling cutter of claim 2 wherein said wedge includes a first surface engageable with the side wall of said slot opposite said insert seat, and a second surface engageable with a top face of the cutting insert.

4. The milling cutter of claim 2 wherein the wedge actuator comprises a screw having one end thereof threadably engaged with an opening in the cutter body.

5. The milling cutter of claim 2 wherein said wedge actuate comprises a differential screw having two oppositely threaded ends with one end engaged in a first threaded opening in said cutter body and the opposite end engaged in a second threaded opening in said wedge.

6. The milling cutter of claim 1 wherein said securing means comprises a securing screw.

7. A milling cutter capable of receiving replaceable cutting inserts of different shapes and sizes comprising:

(a) a generally cylindrical cutter body having an outer periphery; (b) a plurality of insert seats for receiving cutting inserts of a first predetermined size and shape formed or for receiving adapters in the outer periphery of the cutter body;

(c) a plurality of adapters insertable into respective insert seats in the cutter body, each adapter having a second insert seat formed therein for receiving a cutting insert of a second predetermined shape and size;

(d) securing means for securing said adapters in their respective insert seats in the cutter body; and

(e) clamping means operable to clamp a first cutting insert of said first predetermined size and shape in said first insert seat, and to clamp a second cutting insert of said second predetermined size and shape in said second insert seat in said adapter.

8. The milling cutter of claim 7 wherein said clamping means comprises a wedge and a wedge actuator.

9. The milling cutter of claim 8 wherein said wedge actuator comprises a screw having one end threadably engaged with an opening in the cutter body.

10. The milling cutter of claim 8 wherein said wedge actuator comprises a differential screw having two oppositely threaded ends with one end engaged and a first threaded opening in said cutter body and the opposite end engaged in a second threaded opening in said wedge.

11. A method for mounting cutting inserts of different shapes and sizes in a milling cutter having a plurality of first insert seats formed in its outer periphery for receiving cutting inserts of a first predetermined size and shape, comprising:

(a) mounting an adapter having a second insert seat within said first insert seat in said cutter body, wherein said second insert seat is adapted to receive a cutting insert of a second predetermined shape and size;

(b) securing said adapter within said first insert seat in said cutter body; (c) mounting a cutting insert of said second predetermined shaped and size in said second insert seat in said adapter; and

(d) clamping said cutting insert within said second insert seat.

12. The method of claim 11 wherein the step of clamping said cutting insert of said second predetermined shape and size in said adapter comprises the step of engaging the second cutting insert with a clamp so as to secure the second insert of the second predetermined shape and size within the adapter.