US 4,765,205 AGranted

Method of assembling drill bits and product assembled thereby

OwnerBob Higdoninventor

Life of this patent

Estimating the term…

Loading patent…

Abstract

A method for assembling earth drill bits starts with a hollow shank body with a hollow pin with API regulation threads, for connection to a drill pipe, extending from one side, and hollow nozzle legs extending from the other side cast as a one piece investment casting. Separate leg members are rough formed and machined to shape having a bit body portion, depending leg, and inwardly and downwardly extending bearing journal. Conical roller cutters are supported for rotation on the bearing journals. A passage formed through the bit body portion and depending leg provides for lubrication of the conical roller cutters. The conical roller cutters are secured in place by a liquid lock formed by filling a cavity between the interior of the cutter cone and the journal bearing which is filled with liquid and sealed. The bit body portions fit together and are welded to form a sub-assembly with an end wall for the hollow pin and side recesses receiving the hollow nozzle legs (containing interchangeable hard metal nozzle members) and are welded peripherally to the open end of the hollow shank body. A ceramic or hard-metal insert at the open end of the hollow shank body is secured in place when the shank body and bit body sub assembly are welded together and protects against abrasion from drilling fluid flowing through the hollow pin.

Claims60

Dependent claims

A method of assembling drill bits, for rotary earth drilling, of the type comprising a bit body having a shank body with a threaded pin adapted to be detachably secured to drill pipe or the like for rotating the bit and delivering drilling fluid to the bit for removal of spoil or cuttings, a plurality of depending leg members at the lower end thereof, each leg member being uniformly spaced from the other leg members, and having an inwardly and downwardly extending bearing journal at the respective lower ends thereof and a plurality of nozzles for exit of drilling fluid from said bit body, and a plurality of roller cutters, one for each leg, each comprising a generally conical cutter body rotatably mounted on the respective journal and a plurality of cutting elements on each cutter body,

said method comprising the steps of
(a) casting as a single piece a hollow shank body with a threaded hollow pin extending from one side and a plurality of hollow nozzle legs opening from the interior of said hollow pin and extending from the other side of said shank body in the opposite direction from said pin and angled outward from the longitudinal center line thereof,
(b) forming as separate pieces said leg members, each leg member comprising a one piece bit body portion with a depending leg and an inwardly and downwardly extending bearing journal at the lower end thereof,
(c) forming each bit body portion to fit together to form an assembled bit body sub-assembly with an end wall for said hollow pin and defining peripheral recesses when assembled to receive said hollow nozzle legs,
(d) assembling said conical roller cutters on said bearing journals,
(e) assembling said bit body portions and welding them together to form said bit body sub-assembly having a body portion fitting the open end of said hollow shank body and having equally spaced peripheral recesses, said legs depending therefrom and having said bearing journals extending inwardly and downwardly at the lower ends thereof,
(f) assembling said bit body sub-assembly against the open end of said shank body with said nozzle legs extending through said peripheral recesses, and said bit body closing the open end of said hollow pin, and
(g) welding said bit body sub-assembly around the periphery thereof to said shank body.

5 more elements

A method of assembling drill bit body assemblies, for drill bits for rotary earth drilling, of the type comprising a bit body having a shank body with a threaded pin adapted to be detachably secured to drill pipe or the like for rotating the bit and delivering drilling fluid to the bit for removal of spoil or cuttings, a plurality of depending leg members at the lower end thereof, each leg member being uniformly spaced from the other leg members, and having an inwardly and downwardly extending bearing journal at the respective lower ends thereof and a plurality of nozzles for exit of drilling fluid from said bit body, and said bearing journals being adapted to support a plurality of roller cutters, one for each leg, each comprising a generally conical cutter body for rotation thereon,

said method comprising the steps of
(a) casting as a single piece a hollow shank body with a threaded hollow pin extending from one side and a plurality of hollow nozzle legs opening from the interior of said hollow pin and extending from the other side of said shank body in the opposite direction from said pin and angled outward from the longitudinal center line thereof,
(b) forming as separate pieces said leg members, each leg member comprising a one piece bit body portion with a depending leg and an inwardly and downwardly extending bearing journal at the lower end thereof,
(c) forming each bit body portion symmetrically to fit together to form an assembled bit body sub-assembly with an end wall for said hollow pin and defining peripheral recesses when assembled to receive said hollow nozzle legs,
(d) assembling said bit body portions and welding them together to form said bit body sub-assembly having a body portion fitting the open end of said hollow shank body and having equally spaced peripheral recesses, said legs depending therefrom and having said bearing journals extending inwardly and downwardly at the lower ends thereof,
(e) assembling said bit body sub-assembly against the open end of said shank body with said nozzle legs extending through said peripheral recesses, and said bit body closing the open end of said hollow pin, and
(f) welding said bit body sub-assembly around the periphery thereof to said shank body.

4 more elements

Dependencies are inferred from the claim text.