Cutting by use of rotating axially moving tool – With means to apply transient – fluent medium to work or product – Including tool with duct
Patent
1998-09-25
2000-09-26
Howell, Daniel W.
Cutting by use of rotating axially moving tool
With means to apply transient, fluent medium to work or product
Including tool with duct
408144, 408200, 408230, 761081, B23B 5102
Patent
active
061234893
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The invention is related to a drilling tool for machine tools, comprising a tool head having at least one cutting edge, a tool shank joining the tool head and being adapted to be clamped in a tool holder of the machine tool with an end opposed to the tool head, at least one straight or helical chip groove formed into the surface of the shank and extending from the tool head in the direction of chip flow along at least part of the length of the shank, and a sleeve encompassing the tool shank and thereby covering the chip groove at least over a part of its length under formation of a closed chip channel. The invention is further related to a Method for manufacturing such a drilling tool.
BACKGROUND OF THE INVENTION
Drilling tools of the type described above are used for either solid drilling or for boring, profile facing or spot facing of predrilled bores. When drilling into solid material or when finishing pocket bores, the removal of chips may be aided by the use of a coolant and lubricant which emerges from the shank tip at a high pressure and washes the chips out of the bore by way of the chip groove. When the chip grooves are radially open, the chips which are forced radially outwards due to the centrifugal force of the tool rotating within the bore travel mainly along the wall of the bore. In pre-drilled bores, in the walls of which recesses such as pockets or cross bores are present, there is the disadvantage that the chips enter the recesses and cannot flow out anymore. The chips then have to be removed in a time consuming further step.
In order to avoid this disadvantage it is known (DE-A-40 33 877) in a drilling tool of the type described above to provide the tool shank with a close-fitting sleeve which extends from the tool head in the direction of the clamped end. The chip grooves and the inner wall of the sleeve thereby delimit channels through which the chips created in the drilling process are removed. Since the tool head radially protrudes over the circumference of the tool shank and therefore has a larger diameter than the inner diameter of the sleeve, in the known drilling tool the sleeve can only be mounted on the tool shank from the clamping end. In drills having a reinforced shank and in stepped drills the fitting of such a sleeve is not possible at all.
Based on this it is the object of the invention to develop a drilling tool and a method of production thereof, with which closed channels for removing chips can be provided for different types of drilling tools.
SUMMARY OF THE INVENTION
The solution according to the invention is based on the idea that the sleeve and/or the tool are designed such that the sleeve can be mounted on the tool shank from the side of the drill tip, in spite of the tool head having a larger diameter than the tool shank.
In order to achieve this it is proposed according to a first variant of the invention that the sleeve has a slot extending over the entirety of its length. The slot makes it possible to spread the sleeve apart so far during mounting that it may be pushed over the thickened tool head and fastened thereto in a tightly fitting manner. The sleeve therefore expediently consists of a resilient material, preferably of a spring steel. In order to ensure a secure positioning, it is of advantage when the sleeve lies against the tool shank with its edges which delimit the slot in a surface region away from the at least one chip groove. In the case of a helical drill these edges rest on the raised helix turns between the sunk chip grooves.
The slotted sleeve may be clamped onto the tool shank in a friction-fitting manner and/or be affixed to the tool shank in an integral manner by soldering, glueing or welding. In the latter case the sleeve adds to the torsional and flexural stability of the tool as a load carrying member.
In order to prevent an axial movement of the sleeve on the tool shank, the tool head has an axial shoulder acting as a stop for the sleeve, which shoulder is oriented in the direction of chip flow. The sleeve
REFERENCES:
patent: 1927871 (1933-09-01), Irwin et al.
patent: 3040605 (1962-06-01), Andreasson
patent: 3365987 (1968-01-01), Heller et al.
patent: 3564948 (1971-02-01), Pomernacki
patent: 4123193 (1978-10-01), Hill
Reccius Helmut
Stolz Gerhard
Howell Daniel W.
Komet Praezisionswerkzeuge Robert Breuning GmbH
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