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US 4,951,762 AGranted
Drill bit with cemented carbide inserts
AssigneeSandvik AB
InventorLars-Gunnar Lundell
Life of this patent
Estimating the term…
Abstract
A drill bit of the percussion type includes a bit body of steel, a front portion of which is provided with at least one slot in which an insert is attached by brazing. Brazed between the insert and side walls of the slot are side plates which are of uniform thickness while being thinner than the insert. The side plates are formed of cemented carbide or a metal alloy with a coefficient of linear expansion which for temperatures below 500.degree. C. is substantially smaller than that of steel and the braze metal while being approximately the same as that of the insert.
Claims14
A drill bit comprising:
- a steel bit body having a front surface containing at least one slot;
- an insert formed of cemented carbide having side surfaces disposed in said slot, and a front end projecting from said slot;
- and
- support plate means disposed in said slot and including first side surface means brazed by a braze metal to said side surfaces of said cemented carbide insert and second side surface means brazed to opposing steel side walls of said slot, said support plate means being of substantially uniform thickness, said thickness being substantially smaller than that of said cemented carbide insert, said support plate means formed of cemented carbide or a metal alloy having a coefficient of linear expansion which for temperatures below 500.degree. C. is substantially smaller than that for steel and the braze metal while being approximately the same as that of said cemented carbide insert.
1 more element
A drill bit comprising:
- a steel bit body having a front surface containing at least one slot;
- an insert formed of cemented carbide having side surfaces disposed in said slot, and a front end projecting from said slot;
- and
- support plate means disposed in said slot and brazed by a braze metal to said side surfaces of said insert and to opposing side walls of said slot, said support plate means being of substantially uniform thickness, said thickness insert, said support plate means formed of cemented carbide having a greater weight percent Co than said insert and having a coefficient of linear expansion which for temperatures below 500.degree. C. is substantially smaller than that for steel and the braze metal while being approximately the same as that of said insert.
1 more element
Dependencies are inferred from the claim text.