Patent US3725990A successfully refreshed from Google Patents.
US3725990A
Expired / Lapsed
US
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Method for making non-return valves
Assignee: Danfoss AS
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Filing: 1971-05-12
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Granted: 1973-04-10
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Expires: 1991-05-12
Abstract
Abstract The invention relates to a one-way valve and to a method for manufacturing a one-way valve. The method involves drawing a cupshaped housing from sheet metal in several stages and punching a valve seat in the bottom of the cup. A shoulder is formed in the housing by means of a profiled drawing mandrel and by fitting a washer against the shoulder to serve as a backing member for a tapered spring.
Inventors
- 👤 J Petersen
- 👤 L Sturlason
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 20:03
CPC Classifications
B; B21; B21D; B21D53/00; B21D22/00; B21D22/20; B21D22/26; F; F16; F16K; F16K15/00; F16K15/02; F16K15/04; F16K15/044; Y; Y10; Y10T; Y10T137/00; Y10T137/7722; Y10T137/7837; Y10T137/7904; Y10T137/7922; Y10T137/7927; Y10T29/00; Y10T29/49; Y10T29/49405; Y10T29/49409; Y10T29/49412; Y10T29/49416; Y10T29/49423
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
97 words
A method of producing a one-way valve assembly comprising the steps of drawing from sheet-metal in seveRal stages a cup-shaped housing, punching a valve seat in the bottom of said housing, using a profiled drawing mandrel in a drawing operation to form a cylindrically shaped wall having an internal shoulder and a cylindrically shaped free end of reduced thickness surrounding said shoulder, said drawing mandrel having a portion of greater diameter at a selected distance from its end-face, fitting a backing member against said shoulder and bending said free end inwardly into contact with said backing member.
Claim 2
Independent Claim
97 words
A method of producing a one-way valve assembly comprising the steps of drawing from sheet-metal in seveRal stages a cup-shaped housing, punching a valve seat in the bottom of said housing, using a profiled drawing mandrel in a drawing operation to form a cylindrically shaped wall having an internal shoulder and a cylindrically shaped free end of reduced thickness surrounding said shoulder, said drawing mandrel having a portion of greater diameter at a selected distance from its end-face, fitting a backing member against said shoulder and bending said free end inwardly into contact with said backing member.
Claim 3
Dependent Claim
28 words
A method according to claim 1 in which said valve seat is punched in the bottom of said housing prior to the last stage of said drawing operation.
Claim 4
Dependent Claim
39 words
A method according to claim 2 in which said housing is drawn from a round flat blank in such a manner that the bottom of said housing slopes downwards from the periphery towards the area of said valve seat.
Claim 5
Dependent Claim
23 words
A method according to claim 1 in which after said drawing the required length of said housing is obtained by a severing operation.
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) | 1976-04-09 | 1976-10-09 | 1977-04-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-09 | 1980-10-09 | 1981-04-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-09 | 1984-10-09 | 1985-04-10 | $7700.00 | Window Closed / Lapsed |