Patent US3577850A successfully refreshed from Google Patents.
US3577850A
Expired / Lapsed
US
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Method of forming seals
Assignee: PRECISION SAMPLING CORP
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Filing: 1968-09-26
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Granted: 1971-05-11
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Expires: 1988-09-26
Abstract
Abstract A method, and the apparatus formed by encapsulating and stress forming a thermoplastic material upon a male member, e.g., the needle or plunger of a syringe, or both, to provide a durable and effective leakproof seal when inserted within enclosing walls defining an opening of restricted diameter. A portion of the said male member is capped with an oversized thermoplastic material, the cap is then reduced in size to correspond to the diameter of the member with which it is to be mated in forming the seal, and then heated up to or just below the softening temperature of the thermoplastic material, generally up to about 425* F., and preferably to about 300* F. The heat stressed member, which is characterized as having very thin layers or films of the stress formed thermoplastic covering the external surface of the member, can then be inserted into snug fit within the mating bore, e.g., the barrel of a syringe, and the tight fit will endure because of the elastic memory of the material by virtue of which it tends to expand to its former size and shape thereby pressing against the enclosing sidewalls forming the bore.
Inventors
- 👤 Rano J Harris Sr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 12:46
CPC Classifications
A; A61; A61M; A61M5/00; A61M5/178; A61M5/31; A61M5/315; A61M5/31511; A61M5/31513; B; B29; B29C; B29C55/00; B29C55/30; B29C65/00; B29C65/56; B29C65/565; B29C66/00; B29C66/01; B29C66/05; B29C66/10; B29C66/12; B29C66/122; B29C66/1222; B29C66/1224; B29C66/50; B29C66/51; B29C66/53; B29C66/534; B29C66/5344; B29C66/61; B29C66/612; A61M5/31525; A61M5/31531; B29C66/126; B29L; B29L2031/00; B29L2031/748; B29L2031/7494; B29L2031/753; B29L2031/7544; Y; Y10; Y10S; Y10S277/00; Y10S277/924; Y10T; Y10T29/00; Y10T29/49; Y10T29/49826; Y10T29/49908; Y10T29/49915; Y10T29/49917; Y10T29/49925; Y10T29/49927; Y10T29/49929; Y10T29/49934
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
164 words
A method of encapsulating and stress forming a thermoplastic material upon a male member to form, with enclosing walls defining a restricted opening of preselected diameter, a durable effective leakproof seal for openings corresponding to the said preselected diameter comprising: reducing the original outside diameter of a portion of a male member around its circumference to provide a retention surface, covering in part the portion of the male member of reduced diameter with a thermoplastic cap of larger outside diameter than that of the opening, forcing the capped end of the male member into the restricted opening to reduce the outside diameter of the cap to correspond to that of the said opening, providing an encapsulated portion having a membrane thickness in contact with the enclosing walls ranging no greater than about 0.005 inch, and then heating the capped end of the male member contained within the restricted opening up to the softening temperature of the thermoplastic material of which the cap is composed.
Claim 2
Independent Claim
164 words
A method of encapsulating and stress forming a thermoplastic material upon a male member to form, with enclosing walls defining a restricted opening of preselected diameter, a durable effective leakproof seal for openings corresponding to the said preselected diameter comprising: reducing the original outside diameter of a portion of a male member around its circumference to provide a retention surface, covering in part the portion of the male member of reduced diameter with a thermoplastic cap of larger outside diameter than that of the opening, forcing the capped end of the male member into the restricted opening to reduce the outside diameter of the cap to correspond to that of the said opening, providing an encapsulated portion having a membrane thickness in contact with the enclosing walls ranging no greater than about 0.005 inch, and then heating the capped end of the male member contained within the restricted opening up to the softening temperature of the thermoplastic material of which the cap is composed.
Claim 3
Dependent Claim
71 words
The method of claim 1 wherein the male member is suitable for use as a plunger for a syringe and the terminal end thereof is reduced in diameter, a portion of the member behind and adjacent to the terminal end is further reduced in diameter to provide a recessed portion, and the volume of the recessed portion is sufficient to contain the thermoplastic material when the cap is reduced in diameter.
Claim 4
Dependent Claim
29 words
The method of claim 2 wherein the original outside diameter of the plunger, inclusive of the total thickness of the membrane, ranges up to about 0.042 inch in diameter.
Claim 5
Dependent Claim
11 words
The method of claim 2 wherein the thermoplastic material is Teflon.
Claim 6
Dependent Claim
23 words
The method of claim 1 wherein the thermoplastic cap, after reduction in size, is heated to temperatures ranging up to about 425* F.
Claim 7
Dependent Claim
17 words
The method of claim 5 wherein the temperature ranges from about 200* F. to about 300* F.
Claim 8
Dependent Claim
22 words
The method of claim 1 wherein the membrane thickness of the thermoplastic material ranges from about 0.001 inch to about 0.005 inch.
Claim 9
Dependent Claim
19 words
The method of claim 1 wherein the male member is a tubular needle, suitable for use in a syringe.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-05-10 | 1974-11-09 | 1975-05-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-10 | 1978-11-09 | 1979-05-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-10 | 1982-11-09 | 1983-05-11 | $7700.00 | Window Closed / Lapsed |