US 6,684,968 B2 · Roof bit body and insert assembly

Abstract

A center vacuum rotary drill bit including a rotary drill bit body and an insert. The bottom surface of the slot has a projecting key that cooperates with a depression keyway of the insert. Generally vertical sidewall surfaces of a depression keyway and vertical surfaces of a projection key provide mechanical resistance against lateral movement of the cutting insert. This mechanical resistance reduces displacement of the insert with respect to the bit body during brazing and thus a high quality, accurately aligned drill bit assembly is provided by applicants' invention. The depression keyway is designed so as to minimize the effect of the axial load on the insert by avoiding sharp corners which tend to amplify nominal stress and provides an insert of a proper carbide density after pressing. Integral bit body protuberances adequately separate the insert within the slot and permit braze flow between the insert and slot. The protuberances enhance braze flow when braze is fed between the insert body and bit body.

Claims15

Dependent claims

A rotary drill bit assembly comprising:

a rotary drill bit body having a top working surface and a slot extending transversely across said top working surface, said slot including a first sidewall, an opposite second sidewall and a first bottom surface extending between said first sidewall and said second sidewall;
an insert positioned within said slot, said insert including a second bottom surface having a U-shaped depression formed therein, said first bottom surface having a U-shaped projection such that said projection supports said depression,
wherein the U-shaped depression forms a void that makes said insert approximately between 30%-50% by weight less than an insert of equal dimension without a depression therein.

Dependencies are inferred from the claim text.

Roof bit body and insert assembly

Life of this patent

Roof bit body and insert assembly

Life of this patent

Abstract

Claims15