US 4,762,189 AGranted

Seal and seal shield assembly for rotary drill bits

OwnerDavid M. Tatuminventor

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Abstract

A seal and seal shield assembly for rotary drill bits having a journal member comprising a first bearing member, and a rolling cutter with a bore having an open end rotatably mounted thereon comprising a second bearing member. The rolling cutter has a counterbore at the open end defining an annular cavity. The seal and seal shield assembly is compression-loaded in the cavity to retain lubricant in the bit. The seal assembly has a pair of annular rings each with a radially extending wall and an axially extending wall defining an annular seal gland. An elastic spring member compression-loaded in the seal biases the exterior surfaces against the bearing surfaces. A flat malleable annular disc with lubricating properties is positioned at the outer face of the seal assembly and a rigid annular disc is positioned in supporting relation thereto. A second flat malleable annular disc is positioned at the outer face of the rigid disc adjacent to the journal member seal thrust face. The malleable annular disc members deform under pressure and extrude to seal voids at the bearing surfaces and to prevent the entrance of abrasive particulate matter.

Claims33

Dependent claims

A seal and seal shield assembly for a rotary drill bit of the type comprising

a main bit body having at least one leg extending downwardly therefrom
said leg having a generally cylindrical journal extending radially inward therefrom comprising a first bearing member of the bit,
said journal having end bearing surface on the surface of said leg at the juncture of the journal therewith,
a hollow roller cutter with an open end rotatably mounted on each journal, having a bore forming a bearing surface cooperable with said journal, and having a counterbore at the open end thereof defining an annular seal cavity in cooperation with the peripheral surface of said journal and said journal end bearing surface with a peripheral opening therefrom,
said annular seal cavity having a fixed end wall comprising said journal end bearing surface, a journal end wall on said roller cutter spaced from said journal end bearing surface and movable relative thereto, a fixed side wall comprising the peripheral surface of said journal, and a side wall on said roller cutter spaced from said journal peripheral surface and movable relative thereto, and
means for introducing lubricant into the space between said hollow cutter and said journal,
said seal and seal shield assembly comprising
a first flat annular disc of a soft malleable, corrosion-resistant metal, extrudable under conditions of temperature and pressure normally encountered during use, with lubricating properties, positioned in said annular bearing cavity and engageable in bearing relation with said journal end bearing surface,
a second flat annular disc of a strong, rigid material positioned in said annular seal cavity in supporting relation to said first disc, and
spring means in said annular seal cavity biasing said second disc to urge said first disc against said journal end bearing surface so that said first disc maintains bearing contact therewith and extrudes through said seal cavity peripheral opening under load.

7 more elements

A seal and seal shield assembly for a rotary shaft assembly of the type comprising

a main body having at least one shaft extending outwardly therefrom and having an end bearing surface at the shaft juncture,
a hollow rotary member mounted on said shaft for relative rotary movement and having a bore forming a bearing surface cooperable with said shaft, and having a counterbore at the open end thereof defining an annular seal cavity in cooperation with the peripheral surface of said shaft and said body end bearing surface with a peripheral opening therefrom,
said annular seal cavity having a fixed end wall comprising said body end bearing surface and a shaft end wall on said rotary member spaced from said end bearing surface and movable relative thereto, and a fixed side wall comprising the peripheral surface of said shaft and a side wall on said rotary member spaced from said shaft peripheral surface and movable relative thereto, and
lubricant contained in the space between said rotary member and said shaft,
said seal and seal shield assembly comprising
a first flat annular disc of a soft malleable, corrosion-resistant metal, extrudable under conditions of temperature and pressure normally encountered during use, with lubricating properties, positioned in said annular seal cavity and engageable in bearing relation with said shaft end bearing surface,
a second flat annular disc of a strong, rigid material positioned in said annular seal cavity in supporting relation to said first disc, and
spring means in said annular seal cavity biasing said second disc to urge said first disc against said end bearing surface so that said first disc maintains bearing contact therewith and extrudes through said seal cavity peripheral opening under load.

5 more elements

Dependencies are inferred from the claim text.