US 4,293,252 AGranted

Drill bit

AssigneeMapal Fabrik fur Prazisionswerkzeuge

InventorsDieter Kress, Friedrich Haberle

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Abstract

A plurality of cutting plates are mounted in a recess forming a mouth at one end of a drill bit and each cutting plate has a plurality of cutting edges. The drill bit mouth provides chip removal. In the cutting position, the cutting plates are arranged in a plane extending in the direction of the axis of rotation of the drill bit and the cutting edges are arranged in a step-wise manner. The cutting plates can be turned for arranging different ones of the cutting edges in the cutting position. The cutting plates extend radially outwardly from the axis of rotation with one plate adjacent the axis of rotation and the at least one other plate extending radially outwardly from it. The cutting plates have a parallelogram shape in the axial plane of the cutting position. In the cutting position, cutting edges of the cutting plates are in parallel relation to one another with adjacent parallel cutting edges on adjacent cutting plates being in contact with one another. Within the cutting position, the cutting plates are adjustably displaceable in the radial direction. Further, the cutting plates can be secured in the desired position.

Claims7

Dependent claims

Drill bit having an axis of rotation with a first end extending transversely of the axis of rotation, said first end having a recess therein forming a drill bit mouth for chip removal, a plurality of turnable cutting plates located in the cutting position in a plane extending generally in the direction of the axis of rotation and also radially outwardly from the axis of rotation, each said cutting plate having a plurality of cutting edges with the active cutting edges arranged in the cutting position being disposed in a step-wise manner in the axial plane of said cutting plates, wherein the improvement comprises that in the axial plane in the cutting position said cutting plates have a parallelogram shape and said cutting edges on said cutting plates include main cutting edges with at least certain of said main cutting edges on one of said cutting plates being in parallel relation with at least certain of said main cutting edges on an adjacent one of said cutting plates, a parallel said main cutting edge on one of said cutting plates being disposed in contact with a corresponding parallel said main cutting edge on the adjacent one of said cutting plates, said recess in said first end of said drill bit having a shoulder formed therein providing a support for said cutting plates, and means for radially adjustably positioning said cutting plates in the cutting position.

Dependencies are inferred from the claim text.