Percussive rock drill bit and buttons therefor and method for manufacturing drill bit
AssigneeSandvik AB
InventorsJohan Linden, Lars-Gunnar Lundell
Life of this patent
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Abstract
A percussive rock drill bit includes a head portion with a forward surface surrounded by a peripheral surface. The peripheral surface supports a wreath of peripheral buttons. Front buttons are mounted to the forward surface inside the wreath of peripheral buttons. The button shave a diameter (D) and a height (H), wherein H/D<1.2. The buttons are welded to an essentially flat part of the forward surface whereby the buttons are metallurgically bound to the head portion.
Claims9
A rock drill bit for percussive drilling comprising a bit body having a working end formed by a forward surface and a surrounding peripheral surface, peripheral buttons arranged in the peripheral surface in the form of a peripheral wreath of peripheral buttons, front buttons arranged in the forward surface inside of the wreath of peripheral buttons, at least one of the front buttons being welded to a substantially flat portion of the forward surface, the at least one button having a protruding portion which protrudes from the forward surface, the protruding portion having a diameter D and a height H, wherein H/D<1.2, the at least one button being metallurgically bound to the forward surface.
A button adapted to be mounted on a forward surface of a rock drill bit for percussive drilling, the button formed of hard metal and having an operative working end intersected by a center axis of the button, the button having a lower side and a protruding portion protruding forwardly from the lower side, the protruding portion having a maximum diameter D and a height H, wherein H/D<1.2;
- the lower side being at least partly conical.
A method of manufacturing a rock drill bit for percussive drilling, the bit comprising a body having a head portion on which a working end of the button is disposed, the working end comprising a forward surface and a surrounding peripheral surface, peripheral buttons arranged in the peripheral surface to form a wreath of peripheral buttons, front buttons arranged in the forward surface, each peripheral button and front button including a protruding portion protruding forwardly from the working end, the protruding portion having a maximum diameter D and a height H, the method comprising the steps of:
- A) providing a source of current having two electric poles,
- B) connecting one of the poles to the bit body and the other pole to at least one of the buttons having a ratio of H/D<1.2,
- C) converging the forward surface and the at least one button such that an electric arc is formed between the forward surface and the button, the electric arc melting opposing faces of the forward surface and the button,
- D) pressing the button against the forward surface,
- E) allowing the opposing faces to solidify, and
- F) repeating steps A-E for other buttons of the bit having a ratio H/D<1.2.
Dependencies are inferred from the claim text.