GB1589341A

GB1589341A - Cutting insert holder for a machine tool

Info

Publication number: GB1589341A
Application number: GB3233277A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1977-08-02
Filing date: 1977-08-02
Publication date: 1981-05-13
Also published as: FR2399889A1; FR2399889B1

Description

(54) CUTTING INSERT HOLDER FOR A MACHINE TOOL (71) I, KINICHI KANEKO, of No. 5006, Kifu-cho Niigata-shi, Niigata-ken, Japan, a Japanese Citizen, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a cutting tool and, more particularly, to a tool holder for a barshaped cutting insert.

Conventional cutting tools are uneconomical since an insert is brazed to the end of a shank in such tools so that both the insert and the shank are discarded as soon as the cutting egde of the insert sustains wear. Further, although cutting tools have heretofore been used in which a triangular or rectangular insert is replaceably secured to the end of a shank, in tools of this type the insert must be replaced by a new one as soon as the cutting edge of the insert is dulled by wear. At the same time, a precise cut cannot be obtained since the force which secures the insert to the shank is not sufficient.

According to the present invention, there is provided a tool holder for a bar-shaped cutting insert comprising: a shank having an insert retaining bore obliquely extending through a front end of the shank through which the barshaped cutting insert is passed, and a hole intersecting with said insert retaining bore; a clamping collar slidably disposed in said hole and having a groove adapted to be engageable with an outer periphery of said bar-shaped cutting insert; and a clamp-actuating member disposed in said hole and having an eccentric shaft portion extending axially through a central bore in said clamping collar to cause said clamping collar to be brought into clamping engagement with said bar-shaped cutting insert when said actuating member is rotated.

In the accompanying drawings, Fig. 1 is a perspective view of a preferred embodiment of a tool holder according to the present invention; Fig. 2 is a section taken on line A-A of Fig. 1; Fig. 3 is a disassembled view of the tool holder shown in Fig. 1; and Fig. 4 is a side view of a part of the tool holder shown in Fig. 3, showing a part of an insert received in a groove of a clamping collar.

In Fig. 1, there is shown a preferred embodiment of a tool holder according to the present invention. In Figs. 1 and 2 a cylindrical cutter insert 2 is passed through an insert retaining bore la obliquely extending through the front end of a shank 1 which is formed with a clamping hole 1b intersecting with the retaining bore la. The clamping hole lb accommodates a clamping collar 4 perpendicular to the axis of the shank. The clamping collar 4 is provided with an obliquely extending elongated engaging groove 3 which engages with bar-shaped cutting insert 2, and a clamp-actuating member 6 having an eccentric shaft 5 is passed through clamping collar 4 and shank 1 and engageable with the shank so as to be rotatable within the collar and shank. Reference numeral 8 denotes a socket for a wrench.

According to the construction described above, turning the clamp-actuating member 6 in a clockwise direction allows eccentric shaft 5 to slide clamping collar 4 under pressure toward insert 2 so that the insert is tightly clamped due to the engagement between the insert and the elongated groove 3 of the clamping collar 4.

Next, turning clamp-actuating member 6 in the counter-clockwise direction causes eccentric shaft 5 to urge clamping collar 4 in a direction as will slide it away from insert 2 so that the insert and groove 3 of clamping collar 4 disengage. Thus, since bar-shaped cutting insert 2 is passed obliquely through the end of shank 1 and is slidable until secured by clamp-actuating member 6, the insert can be used repeatedly, even if the cutting edge has been consumed, merely by lengthening the amount at which the insert protrudes from the shank, this being accomplished by loosening clamp-actuating member 6. Since the cutting edge can be sharpened while still attached to the shank, the edge can be simply and accurately sharpened with little grindstone consumption. Further, since the bar-shaped cutting insert 2 is secured to shank 1 in an oblique direction, the force applied to the tool during cutting acts in the lateral direction so that the cutting edge can perform reliably allowing its full width to be used even when force is required for cutting a rough surface. As the cutting edge is the only portion necessary for the cutting operation, it will not suffer damage by being struck with swarf, and high cutting efficiency can be obtained with low cutting resistance.

Thus, as described above, shank 1 is provided with clamping collar 4 which is slid within the shank by the clamp-actuating member 6, 6, cylindrical bar-shaped cutting insert 2 is clamped due to engagement between it and the elongated groove 3 formed in the clamping collar 4, and, whereas bar-shaped cutting insert 2 is passed through shank 1 at an oblique angle, clamping collar 4 and clamp-actuating member are installed in the shank perpendicular to the axis of the holder. Accordingly, bar-shaped cutting insert 2 is secured within the shank at an oblique angle with respect to clamping collar 4 so that the area of clamping engagement between the insert and the collar is maximized.

This secures the insert tightly and safely so as to allow precise cutting. Cutting edge adjust ment can be freely accomplished when the edge is attached to a clampactuating member, and the edge can be easily centered even when attached to a lathe. The edge does not suffer any deterioration in performance as a heat treatment is not required, and the bar-shaped cutting insert can be used to punch holes when it becomes too short to perform a cutting operation.

While the bar-shaped cutting insert has been shown as having round shape in cross section, it should be noted that the bar-shaped cutting insert may have any other suitable cross sections.

Claims

WHAT I CLAIM IS:

1. A tool holder for a bar-shaped cutting insert comprising: a shank having an insert retaining bore obliquely extending through a front end of the shank through which the bar-shaped cutting insert is passed, and a hole intersecting with said insert retaining bore; a clamping collar slidably disposed in said hole and having a groove adapted to be engageable with an outer periphery of said bar-shaped cutting insert; and a clamp-actuating member disposed in said hole and having an eccentric shaft portion extending axially through a central bore in said clamping collar to cause said clamping collar to be brought into clamping engagement with said bar-shaped cutting insert when said actuating member is rotated.

2. A tool holder according to claim 1, in which said engaging groove of said clamping collar extends in an oblique direction relative to its axis.

3. A tool holder substantially as shown and described with reference to the accompanying drawings.