Rock drill
AssigneeHawera Probst GmbH & Co.
InventorMathias Fuss
Life of this patent
Estimating the term…
Abstract
A rock drill for rotary hammers is proposed in which a conveying helix (3) having main and secondary webs (6 to 9) is used. A one-piece carbide crown, with its wing-shaped main and secondary lips (24 to 27), is butt-welded to the conveying helix.
Claims13
Rock drill for hand-guided rotary hammers, percussion drilling machines and rotary drilling machines, having a drill head (2) and a single- or multi-start conveying helix (3) adjoining this drill head (2), the conveying helix (3) having helically encircling main webs (6, 7) with an outside diameter d1 and likewise helically encircling secondary webs (8, 9) with a smaller outside diameter d2, the main and secondary webs having conveying edges (12 to 15) in disposal flutes (16 to 19) for transporting drillings, characterized in that the drill head (2) is formed from a one-piece carbide crown (21) which is connected to the conveying helix (3) by means of a welded or brazed joint or the like in such a way that in each case the main webs (6, 7) are joined to the main lips (24, 25) and the secondary webs (8, 9) are joined to the secondary lips (26, 27), and in that the outside diameter (D1) formed by the longitudinal extent of the main lips (24, 25) is equal to or slightly larger than the outside diameter (d1) of the main webs (6, 7), and in that the outside diameter (D2) formed by the longitudinal extent of the secondary lips (26, 27) is set back relative to the outside diameter (D2) of the main lips (24, 25).
Rock drill according to one of the preceding claims, characterized in that the main and secondary lips (24 to 27) of the carbide crown (21) are designed in a cross shape or X-shape in plan view.
Rock drill according to one of the preceding claims, characterized in that the carbide crown (21) has a centering point (35) or at least one or more centering lips.
Rock drill according to one of the preceding claims, characterized in that the conveying helix (3) is of two-start design, having two helically encircling main webs (6, 7) and two secondary webs (8, 9) lying in between in each case.
Rock drill according to one of the preceding claims, characterized in that the outside diameter of the main carbide lips (24, 25), which forms the nominal diameter D1, is larger than the outside diameter D2 of the secondary lips (26, 27), where D2≅0.5 to 0.9×D1 and in particular 0.7 to 0.8×D1.
Rock drill according to one of the preceding claims, characterized in that the thickness s1 of the main lip (24, 25) is approximately the same width as, slightly wider than or slightly narrower than the land width s2 of the main webs (6, 7).
Rock drill according to one of the preceding claims, characterized in that the secondary web (8, 9) has a land tapering to a point.
Rock drill according to one of the preceding claims, characterized in that the secondary web (8, 9) is designed as a prominence relative to the flute root, this prominence being rectangular, trapezoidal, semi-trapezoidal, triangular, crowned, hemispherical in cross section, the land of the secondary web (8, 9) preferably being designed so as to taper to a point or to a flat or round end.
Rock drill according to one of the preceding claims, characterized in that, to form bearing surfaces for drillings, the conveying edges (12 to 15) of the main webs (6, 7) and/or of the secondary webs (8, 9) run approximately at right angles to the drill longitudinal axis (44).
Rock drill according to one of the preceding claims, characterized in that the carbide crown (21) has a connecting surface (38) which to a very large extent is flat and has in particular additional centering and/or positioning aids.
Rock drill according to one of the preceding claims, characterized in that the cutting edges (31, 32) of the main and secondary lips (24 to 27) are arranged in a plane (45) lying perpendicularly to the drill longitudinal axis (44).
Dependencies are inferred from the claim text.