US4552228A — Low pressure differential compensator

Claim 1

Independent Claim 159 words

A low pressure differential compensator for use in a sealed rotary rock bit of the type having at least one leg forming part of a bit body, the leg having a journal pin for rotatably supporting a rotatable cutter, said rotatable cutter and journal pin having a seal therebetween, comprising: a lubricant reservoir disposed within said bit body and communicating with a bearing area between said rotatable cutter and said journal pin, and a flexible elongated diaphragm of a truncated cone shape configuration where the walls of the cone have opposed longitudinally extending linear crests, each crest having opposite sloping surfaces, each surface joining the sloping surface of the adjoining crests to form an undulatory cross section, said diaphragm located within said lubricant reservoir for separating said reservoir into a lubricant region and a borehole fluid region, said diaphragm extending radially with respect to the longitudinal axis of said reservoir in response to a pressure differential across the seal.

Claim 2

Dependent Claim 159 words

A low pressure differential compensator for use in a sealed rotary rock bit of the type having at least one leg forming part of a bit body, the leg having a journal pin for rotatably supporting a rotatable cutter, said rotatable cutter and journal pin having a seal therebetween, comprising: a lubricant reservoir disposed within said bit body and communicating with a bearing area between said rotatable cutter and said journal pin, and a flexible elongated diaphragm of a truncated cone shape configuration where the walls of the cone have opposed longitudinally extending linear crests, each crest having opposite sloping surfaces, each surface joining the sloping surface of the adjoining crests to form an undulatory cross section, said diaphragm located within said lubricant reservoir for separating said reservoir into a lubricant region and a borehole fluid region, said diaphragm extending radially with respect to the longitudinal axis of said reservoir in response to a pressure differential across the seal.

Claim 3

Dependent Claim 19 words

The low pressure compensator as described in claim 1 wherein said longitudinally-extending crests are integrally formed in the diaphragm.

Claim 4

Dependent Claim 27 words

The low pressure differential compensator as described in claim 1 wherein the diaphragm includes an upper end portion having a raised contour on its outer peripheral surface.

Claim 5

Dependent Claim 123 words

A low pressure differential compensator for use in a sealed rotary rock bit having a lubrication system including a lubricant reservoir, the reservoir providing lubricant to a bearing area between relatively rotatable elements having a seal therebetween, comprising: a flexible elongated diaphragm of a truncated cone configuration where the walls of the cone have opposed longitudinally extending linear crests, each crest having opposed sloping surfaces, each surface joining the sloping surface of the adjoining crest to form an undulatory cross section, said diaphragm located within said lubricant reservoir for separating said reservoir into a lubricant region and a borehole fluid region, said diaphragm expanding radially with respect to the longitudinal axis of said reservoir in response to a pressure differential across said seal.

Claim 6

Dependent Claim 123 words

A low pressure differential compensator for use in a sealed rotary rock bit having a lubrication system including a lubricant reservoir, the reservoir providing lubricant to a bearing area between relatively rotatable elements having a seal therebetween, comprising: a flexible elongated diaphragm of a truncated cone configuration where the walls of the cone have opposed longitudinally extending linear crests, each crest having opposed sloping surfaces, each surface joining the sloping surface of the adjoining crest to form an undulatory cross section, said diaphragm located within said lubricant reservoir for separating said reservoir into a lubricant region and a borehole fluid region, said diaphragm expanding radially with respect to the longitudinal axis of said reservoir in response to a pressure differential across said seal.

Claim 7

Dependent Claim 34 words

The low pressure differential compensator as described in claim 4 wherein said diaphragm includes an upper end portion having a contour surface on its outer peripheral surface for forming a high pressure relief valve.

Claim 8

Dependent Claim 44 words

A low pressure differential compensator as described in claim 5 wherein said lubrication system includes a cover cap attached to said upper end, said cover cap having passages formed therein for communicating the exterior of said rock bit with the interior of said diaphragm.

Claim 9

Dependent Claim 37 words

The low pressure differential compensator as described in claim 6 wherein said lubrication system further includes means for biasing said cover cap and said outer peripheral surface of said diaphragm against a sealing wall of said reservoir.

Claim 10

Dependent Claim 36 words

The low pressure differential compensator as described in claim 7 wherein said means for biasing includes a belleville spring biased against said cover cap by a snap ring secured in an upper wall of said reservoir.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1988-11-11	1989-05-13	1989-11-12	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1992-11-11	1993-05-13	1993-11-12	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1996-11-11	1997-05-13	1997-11-12	$7700.00	Window Closed / Lapsed

Low pressure differential compensator

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