IE42806B1

IE42806B1 - Improvements in cutting tools having disposable inserts

Info

Publication number: IE42806B1
Application number: IE965/76A
Authority: IE
Original assignee: Gen Electric
Priority date: 1975-06-30
Filing date: 1976-05-05
Publication date: 1980-10-22
Also published as: SE7607470L; IE42806L; PL117607B1; JPS5946721B2; GB1557481A; IN144776B; AU1386376A; JPS526184A; FR2316031A1; SE431725B; AU507070B2; DE2620201C2; ATA351476A; YU152476A; ES449066A1; CA1040407A; NL7606318A; ATA11977A; IT1062495B; ES242128Y

Abstract

The metal-cutting tool has an interchangeable cutting insert (9) which is is suitable for resisting high cutting forces. The cutting insert is of solid design and has cutting edges only on its top side and in addition has a recess (14) in which a projection (18) of a clamping finger (17) engages.

Description

This invention relates to cutting tools and in particular to cutting tools having disposable inserts. More particularly, the invention relates to a cutting tool and insert which is especially adapted to withstand heavy cutting forces encountered in taking heavy cuts from metal work pieces.

Metal cutting tools having disposable cutting inserts are well known. Exemplary of such are metal l cutting tools having a body or shank portion and a 10 head portion having a pocket or recess therein for the reception of disposable cutting inserts of various sizes and shapes having one or more cutting edges, such inserts being held in place as by means of a set screw inserted through a hole in the insert and extending through the lower pocket surface into the head portion. Xn some cases, insert seats are provided under the cutting insert, which latter can, adjustably be held in place by clamping means as by the well known bridge or finger clamp, or simply by wedging means incorporated in the insert hole screw as illustrated, for example, in U.S. patents 3,341,920? 3,341,921 and 3,341,923, While prior art arrangements for holding cutting inserts have considerable merit, it has been found that they are lacking in holding power and resistance to the high - 3 forces generated in cutting metals on a massive scale wherein feeds of the order of 1/4 inch or more are used. It has been found, for example, that prior art clamping means tend either to fail under the cutting forces involved or tend to jam, making ready indexing of the insert overly time-consuming or even impractical or impossible. Accordingly, the present invention attempts to provide a metal cutting tool and disposable insert particularly adapted to heavy metal cutting work without physical failure and which, at the same time, lends itself to ready indexing or changing of the cutting edge presented to the work.

Accordingly, the present invention provides a metal cutting tool having shank and head portions, said head portion having a pocket therein said pocket having fixed therein a cutting insert seat conformably fitted to the walls of said pocket, a solid cutting insert having at least one cutting edge on a first major surface thereof mounted on said seat and conformably fitted to the walls of said pocket, said insert having a flat second major surface which is in abutment with said seat and a recess in its first major surface, a bridge clamp mounted on said head, portion a finger of said clamp engaging said insert and when tightened bearing upon and holding said cutting insert in place, the recess provided in said first major surface of the cutting insert having a flat base surface extending substantially parallel to said second major surface of the cutting insert, and a side surface extending substantially perpendicular to the flat base surface and toward said first major surface of the cutting insert, a projection of the clamping finger engaging with the flat base surface of the recess and with a portion of its side surface.

The present invention will be further described by way of example only, with reference to the - 4 accompanying drawings in which Figure 1 is a plan view of an embodiment of the present invention, Figure la is a side elevational view of the embodiment and Figure lb is an elevational cross-sectional view of the direction b-b of Figure 1.

Referring to the drawing, there is shown a metal cutting tool A having a body 2 only partially shown but which can be extended to any size if desired. The cutting tool 1 also has a head portion 3 having therein a recess or pocket 4 which is adapted to be capable of receiving any particular shape of outting insert such as square, round, octagonal, hexagonal or diamond. The walls of pocket 4 are accurately machined and flat, the corners being usually stress relieved as at 5. Mounted in pocket 4 is cutting insert seat 6 held in place by an adjustable screw 7 threaded into hole 8 in the head portion Which can extend as desired and as shown through the head portion. As is usual, the surfaces of seat 6 are accurately formed to fit snugly and tightly, mating against the bottom of pocket 4 and against the walls thereof more adequately to perform its purpose of transferring heat from the cutting edge and to spread cutting forces over the entire area of the pocket to prevent physical failure of and to protect and prolong the life of the pocket. Mounted on insert seat 6 is outting insert 9 which, as pointed out above can be capable of taking any of a number of configurations or shapes although that shown in an exemplary fashion is square. The insert 9 of the present invention has a flat bottom 10 a flat second major surface and preferably has sides which are accurately formed or ground to mate with the corresponding surfaces of seat 6 and the walls of pocket 4. Where lighter duty inserts are indicated, they can, of course, be twosided or have outting edges on the upper and lower faces. - 5 Insert 9 is provided with the cutting edges 12 and as desired with chip breaking grooves 13 which can take any of a number of desired forms which are well known to those skilled in the art. A preferred feature of insert 9 is that for purposes of increased strength there are no holes bored therein for mounting purposes, instead, there is provided in the upper surface i.e. the first major surface of the insert a recess 14 which, while shown as being round, can be any of a number of shapes, such recess cooperating in discussed manner with clamp 15 which also can accept any of a number of shapes but which is shown as of the usual bridge type having a body 16, partially recessed in head portion 3, and an arm or finger 17, the end 18 of which is shaped to mate with the recess 14 of insert 6 to hold the insert firmly in place.

As shown, this end or projection 18 takes the form of a portion of a circle to mate with the arcuate rim of the circular recess 14. With the clamp tightened against insert 6, the mating end or projection 18 and recess 14 serve to hold the insert 9 firmly in place on insert seat 6 and against the walls of pocket 4.

The means for holding clamp 15 in place in head portion 3 of the tool holder 1 is well known as illustrated for example, in U.S. patent 2,955,349 but at the same time serves to enhance the overall resistance to, and suitability for, heavy machining of metals. As shown in Figure lb, the clamp screw 19 extending through the body 16 has an upper portion 20 threaded in one direction in mating threaded hole 21 in clamp body 16, and a lower, oppositely threaded portion 23 threaded through the mating threaded hole 24 in head portion 3. Both the upper and lower ends of clamp screw 20 are typically provided with recessed heads for ready adjustment by means of a mating wrench. It will be seen that by turning the 12806 - 6 top portion 20 of clamp screw 19, clamp 15 can at one and the same time be loosened and lifted from its locking position on the tool holder. When the different ial clamp screw 19 is tightened, such tightening serves to simultaneously lower the clamp 15 into position and to lock the cutter insert 9 in place through the cooperation of projection 18 and recess 14.

As pointed out above, the present invention which is particularly adapted to withstand the massive forces involved in removing large chips from metal work pieces.

Claims

1. CLAIM S:1. A metal cutting tool having shank and head portions, said head portion having a pocket therein said pocket having fixed therein a cutting insert seat conformably fitted to the walls of said pocket, a solid cutting insert having at least one cutting edge on a first major surface mounted on said seat and conformably fitted to the walls of said pocket, said insert having a flat second major surface which is in abutment with said seat and a recess in its first major surface, a bridge clamp mounted on said head, portion a finger of said clamp engaging said insert and when tightened bearing upon and holding said cutting insert in place on said seat, the recess provided in said first major surface of the cutting insert having a flat base surface extending substantially parallel to said second major surface of the cutting insert, and a side surface extending substantially perpendicular to the flat base surface and toward said first major surface of the cutting insert, a projection of the clamping finger engaging with the flat base surface of the recess and with a portion of its side surface.

2. A tool as claimed in claim 1, wherein the recess is a circular-cylindrical whereas the projection on the clamping finger is in the shape of a circular-cylinder which is cut off by a plane parallel to the axis of the cylinder and thus has a segment-shaped cross-section.

3. A metal cutting tool as claimed in claim 1 substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.