Cutters – for shaping – Rotary cutting tool – Including holder having seat for inserted tool
Patent
1996-02-15
1998-10-13
Bishop, Steven C.
Cutters, for shaping
Rotary cutting tool
Including holder having seat for inserted tool
407 51, 83845, B23C 508, B23D 1300
Patent
active
058203095
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD OF THE INVENTION
This invention relates to milling tools for slot milling operations, i.e. rotating tools for milling slots in work pieces and more particularly to the clamping of inserts in such tools.
BACKGROUND OF THE INVENTION
Many different types of rotating milling tools for slots are known. As an example, such a tool can include an essentially disc shaped body having, at its periphery, a number of recesses or cuts in which inserts are arranged. The cuts are arranged in such a way, relative to the inserts, e.g. with essentially radially located complementary abutments portions, that the necessary positioning in axial and circumferential direction, i.e. the direction of working, is achieved. In the radial direction, the tools are secured, other than by the influence of the cutting forces, by friction and clamping action exerted only by material portions adjoining the cuts. This clamping force is dependent on the tolerances between the cut and the insert and could to a certain extent also be influenced negatively by material fatigue in the adjoining material portions.
This implies that the ability of the disc shaped body to retain the inserts is dependent on the rotational speed of the milling tool, i.e. the centrifugal force. One of the most prominent drawbacks of known slot milling tools is their ability the inserts which decreases or ceases when the speed is go beyond the intended one and also when the mater disc shaped body starts to be fatigued. There are known cases where milling discs have been rotated with too high a speed and the inserts like bullets from an automatic weapon have been thrown from the retaining disc causing great hazard for persons nearby. It is obvious that such tools even if they have a warning notation concerning speed limit recommended by the manufacturer are to be regarded as dangerous tools.
One object of the invention is to provide a device eliminating the above mentioned drawbacks for inserts e.g. at too high a rotational speed will cause the inserts leave the tool holder disc.
Another object is to provide a device allowing safe and stable fixation of inserts even in very thin discs.
A further object is to provide a device where the dependency of remaining resiliency characteristics on the the material is to the largest possible extent eliminated and where the locking of the inserts is based on relations between configurations.
Still another object is to make it possible to use a per se known insert in slot milling tools.
SUMMARY OF THE INVENTION
This invention uses inserts of the kind having a shaft with one or more abutment faces being inclined to resist the possible pull out or loosening of the inserts from the device. The inserts being arranged to engage an opposite abutment of the device and besides that to arrange a manually settable abutment in such a way that, independently of the condition of the material, the intended clamping is ensured.
The device according to this invention is characterized by a number of peripherally discrete recesses in a disc shaped insert holder. The recesses have a shape adapted to receive the inserts wherein one side of each such recess includes an essentially V-shaped slot or ridge whereas an opposite side shows a protruding end portion arranged to, in the mounted position of the insert, engage an abutment surface of the insert being inclined from the direction of insertion beyond the top point of the inclined surface. The end portion is a part of a projection separated from the rest of the insert holder body by cuts in three directions to define a tongue like extension which against the inherent resistance of the material is bendable or displaceable relatively to the remainder of the body. In the insert holder body between the side of the tongue like extension facing away from the engagement end portion and an opposite portion of the insert holder body, a settable clamping device is arranged to, in a controllable way, press the tongue like extension towards the insert thereby creating a positive clamping of an
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Brochure from Iscar Hartmetall GmbH.
Bishop Steven C.
Mircona AB
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