US3675935A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Spiral groove seal
Assignee: National Aeronautics and Space Administration
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Filing: 1970-07-13
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Granted: 1972-07-11
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Expires: 1990-07-13
Abstract
Abstract Mating flat surfaces inhibit leakage of a fluid around a stationary shaft. A spiral groove pattern produces a pumping action toward the fluid when the shaft rotates which prevents leakage while a generated hydraulic lifting forces separates the mating surfaces to minimize wear.
Inventors
- 👤 Lawrence P Ludwig
- 👤 Thomas N Strom
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 23:55
CPC Classifications
F; F16; F16J; F16J15/00; F16J15/16; F16J15/34; F16J15/3404; F16J15/3408; F16J15/3412; F16J15/342
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
209 words
Apparatus for forming a seal about a rotatable shaft extending into a container of liquid comprising a pair of juxtaposed members extending about said shaft adjacent said liquid, one of said members comprising a seat mounted on said shaft for rotation therewith, the other of said members comprising a tubular member mounted for reciprocable movement along said shaft, mating surfaces on said members, one edge of each of said surfaces being in contact with said liquid and the opposite edge being exposed to ambient pressure, means for biasing said tubular member toward said seat for moving said surfaces into sealing engagement when said shaft is stationary, spiral grooves in said reciprocable tubular member at its mating surface, said spiral groove being separated by lands substantially coplanar with said mating surface whereby rotation of said shaft pumps a portion of said adjacent contained liquid between said lands to generate a hydraulic lifting force thereby separating said members in opposition to said biasing means while inhibiting leakage, a plurality of passage extending through said tubular member for directing liquid into said spiral grooves, and a feed groove in communication with each of said passages, said feed groove being cut in the bottom of said spiral grooves and extending through said lands.
Claim 2
Dependent Claim
209 words
Apparatus for forming a seal about a rotatable shaft extending into a container of liquid comprising a pair of juxtaposed members extending about said shaft adjacent said liquid, one of said members comprising a seat mounted on said shaft for rotation therewith, the other of said members comprising a tubular member mounted for reciprocable movement along said shaft, mating surfaces on said members, one edge of each of said surfaces being in contact with said liquid and the opposite edge being exposed to ambient pressure, means for biasing said tubular member toward said seat for moving said surfaces into sealing engagement when said shaft is stationary, spiral grooves in said reciprocable tubular member at its mating surface, said spiral groove being separated by lands substantially coplanar with said mating surface whereby rotation of said shaft pumps a portion of said adjacent contained liquid between said lands to generate a hydraulic lifting force thereby separating said members in opposition to said biasing means while inhibiting leakage, a plurality of passage extending through said tubular member for directing liquid into said spiral grooves, and a feed groove in communication with each of said passages, said feed groove being cut in the bottom of said spiral grooves and extending through said lands.
Claim 3
Dependent Claim
184 words
Apparatus for forming a seal about a rotatable shaft extending into a container of liquid comprising a pair of juxtaposed members extending about said shaft adjacent said liquid, mating surfaces on said members, one edge of each of said surfaces being in contact with said liquid and the opposite edge being exposed to ambient pressure, means for biasing one of said members towards the other member for moving said surfaces into sealing engagement when said shaft is stationary, spiral grooves in at least one of said members at its mating surface, said spiral grooves being separated by lands substantially coplanar with said mating surface whereby rotation of said shaft pumps a portion of said adjacent contained liquid between said lands to generate a hydraulic lifting force thereby separating said members in opposition to said biasing means while inhibiting leakage, passage means in one of said members for placing said spiral grooves in communication with said contained liquid to accelerate the generation of said hydraulic lifting force, and a dam surrounding said spiral grooves to increase the hydrodynamic lifting force when the shaft is rotated.
Claim 4
Dependent Claim
184 words
Apparatus for forming a seal about a rotatable shaft extending into a container of liquid comprising a pair of juxtaposed members extending about said shaft adjacent said liquid, mating surfaces on said members, one edge of each of said surfaces being in contact with said liquid and the opposite edge being exposed to ambient pressure, means for biasing one of said members towards the other member for moving said surfaces into sealing engagement when said shaft is stationary, spiral grooves in at least one of said members at its mating surface, said spiral grooves being separated by lands substantially coplanar with said mating surface whereby rotation of said shaft pumps a portion of said adjacent contained liquid between said lands to generate a hydraulic lifting force thereby separating said members in opposition to said biasing means while inhibiting leakage, passage means in one of said members for placing said spiral grooves in communication with said contained liquid to accelerate the generation of said hydraulic lifting force, and a dam surrounding said spiral grooves to increase the hydrodynamic lifting force when the shaft is rotated.
Claim 5
Dependent Claim
37 words
Apparatus for forming a seal about a rotatable shaft as claimed in claim 1 wherein the contained liquid is located outwardly of said spiral grooves so that the pumping of said liquid is aided by centrifugal force.
Claim 6
Dependent Claim
66 words
Apparatus for forming a seal about a rotatable shaft as claimed in claim 1 wherein one of the mating surface is formed on a seat mounted on said shaft for rotation therewith, the other of said surfaces is formed on a tubular member mounted for reciprocable movement along said shaft, and a plurality of passages extending through said tubular member for directing liquid into the grooves.
Claim 7
Dependent Claim
31 words
Apparatus for forming a seal about a rotatable shaft as claimed in claim 2 including a plurality of passages extending through said biased member in a plane normal to said grooves.
Claim 8
Dependent Claim
50 words
Apparatus for forming a seal about a rotatable shaft as claimed in claim 5 including a tubular member mounted for reciprocable movement along the shaft, said tubular member having the spiral grooves and dam formed therein, and passages extending through said tubular member for directing liquid into the spiral grooves.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-07-11 | 1976-01-10 | 1976-07-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-11 | 1980-01-10 | 1980-07-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-11 | 1984-01-10 | 1984-07-11 | $7700.00 | Window Closed / Lapsed |