| 摘要 |
755,653. Hollow drills. ASPLUND, A. J. A., [trading as MASKINFIRMA R. L. CARLSTEDT]. March 3, 1954 [March 4, 1953], No. 6191/54. Class 83 (3). A hollow drill for drilling deep holes, supports at its operative end a cutting tool 18, Figs. 1 and 3, the outer periphery of the drill being non-circular and including a number of peripherallyspaced projections 28 along the length of the drill for centring it in the bore made by the cutting tool which extends from the central axis of the drill to a radial distance greater than the radius of a circle 30 circumscribing the projections, the spaces between the projections providing passages for the flow of cooling liquid under pressure and the hollow drill allowing removal of the liquid and chips from the hole being bored. The axial or helical projections 28, Fig. 2, may be separate members soldered or welded to a round pipe or, may be integral with the shank 10. The shank may extend right up to the cutting end to support the tool 18, Fig. 1, or a separate headpiece 12 may support the tool and be fitted with guides 20, 22, Fig. 3, and be secured by a screwed connection to the shank 10, Fig. 1. A modification includes a shank of originally tubular form deformed into a corrugated triangular form. |
