Boring or penetrating the earth – Bit or bit element – Impact or percussion type
Reexamination Certificate
2007-04-24
2007-04-24
Tsay, Frank (Department: 3672)
Boring or penetrating the earth
Bit or bit element
Impact or percussion type
C175S432000
Reexamination Certificate
active
10509658
ABSTRACT:
A percussion drill bit for drilling a bore includes a drill body having a connecting section at a rear end thereof for connection to a percussive unit, and a plurality of cemented carbide buttons embedded in a front end of the drill body. Each button comprises a cemented carbide body having a rear mounting portion embedded in the drill body, and a front end protruding from the drill body. The front end of the cemented carbide button is substantially semi-spherically curved and defined by a radius whose origin is disposed axially rearwardly of a plane through the largest diameter of the button. The button projects from the drill bit body a distance which is not less than 50% of the button diameter. A conical intermediate surface forms, in cross-section, an acute angle of about 13–19° with an envelope surface of the rear mounting portion.
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patent: 5881828 (1999-03-01), Fischer et al.
patent: 6220376 (2001-04-01), Lundell
Drinker Biddle & Reath LLP
Sandvik Intellectual Property AB
Tsay Frank
LandOfFree
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