Cutters – for shaping – Including cut off tool
Patent
1991-06-27
1992-08-11
Bishop, Steven C.
Cutters, for shaping
Including cut off tool
407116, B27B 2704
Patent
active
051373963
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to a cutoff tool, and more particularly to a cutter of the type having a flank and a cutting face which are adjacent a groove cutting edge, with the flank being disposed at an angle near 90.degree. with respect to the vertical longitudinal center plane of the cutter and providing a lead angle (.kappa.) in the plane of the cutting face. A cutter of this type is made of hard cutting material and is intended to be releasably fixed in a holder in such a manner that the vertical longitudinal center plane of the cutter extends in a groove cutting feed direction. Such cutters may be employed, for example, as cutting tools or milling cutters. In their configuration according to the invention they serve primarily to cut off the ends of workpieces.
Cutoff tools should ensure the flattest possible surface at the end of the cut-off component or workpiece from which a piece has been cut off. The lead angle .kappa. of the cutting edge serves to prevent remainders of the material, for example, in the form of a remaining hump at an end face formed by the groove cutting movement. The lead angle .kappa., however, generates a deflecting pressure F.sub.p which acts on the groove cutting edge and on the cutoff tool. This pressure urges the tool out of its centered position, approximately in the longitudinal direction of the groove cutting edge. This may lead to a rather spherical or hollowed-out surface configuration instead of the desired planar end face.
It is already known to compensate for the deflecting pressures acting on the leading corner of the groove cutting edge by configuring the groove cutting edge so that it ascends in the direction toward the trailing cutting edge corner. This generates a pressure component F.sub.p ' which acts in the direction toward the cutting edge corner that trails during the groove cutting process.
SUMMARY OF THE INVENTION
It is an object of the invention to create a cutoff tool of the above-mentioned type which, on the one hand, compensates for the deflecting pressure resulting from the lead angle (.kappa.) of the groove cutting edge but, on the other hand, also enhances chip formation in the cut groove in the sense of easy and reliable chip removal. This can be accomplished by providing a cutter of the above-mentioned type which is characterized in that the groove cutting edge includes a hallowed-out center region between two end regions, the end regions having end region cutting edges and the center region having a central region cutting edge that is essentially parallel to the end region cutting edges; in that the groove cutting edge also has connecting cutting edges between the central region cutting edge and the end region cutting edges, the connecting cutting edges being disposed at a flank angle (.delta.) with respect to one another; and in that one of the end region outting edges leads in a groove cutting feed direction and the other end cutting edge trails in the groove cutting feed direction, one of the connection cutting edges being disposed adjacent the leading end region cutting edge and forming an angle of inclination (.alpha.) with respect to it, the other connection cutting edge being disposed adjacent the trailing end region cutting edge and forming angle of inclination (.beta.) with respect to it, the angle of inclination (.alpha.) being larger than the angle of inclination (.beta.) and being oppositely directed to the angle of inclination (.beta.). The angle of inclination (.alpha.) preferably has a magnitude such that an outgoing chip remains essentially out of contact with a flank cutting face that is inclined at the angle of inclination (.alpha.), while the angle of inclination (.beta.) is dimensioned so that the outgoing chip remains in contact with a flank cutting face that is inclined at an angle of inclination (.beta.).
The concept of the invention is that, in contrast to prior art cutoff tools of the above-mentioned type, no continuous, straight cutting edge exists, and also that the cutting edge does not asc
REFERENCES:
patent: 2688791 (1954-09-01), Luers et al.
patent: 4776733 (1988-10-01), Pettersson
patent: 4778311 (1988-10-01), Niemi
patent: 5076739 (1991-12-01), Pano
Bishop Steven C.
Hertel AG Werkzeuge+Hartstoffe
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