Patent US3893797A successfully refreshed from Google Patents.
US3893797A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photoflash lamp and method of coating same
Assignee: GTE Sylvania Inc
•
Filing: 1972-07-03
•
Granted: 1975-07-08
•
Expires: 1992-07-03
Abstract
Abstract A photoflash lamp having a vacuum-formed thermoplastic coating for reinforcing the glass envelope of the lamp and enhancing its containment capability upon flashing. Also, a method for applying the coating comprising: locating the glass envelope in a dried, preformed sleeve of thermoplastic material; drawing a vacuum in the space between the sleeve and the envelope; heating the assembly incrementally lengthwise to gradually form the sleeve onto the envelope; and then constricting and tipping off the sleeve at the conclusion of the heating process.
Inventors
- 👤 Harold L Hough
- 👤 Emery G Audesse
- 👤 Thomas J Sentementes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 15:30
CPC Classifications
F; F21; F21K; F21K5/00; F21K5/02
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
64 words
A photoflash lamp comprising an hermetically sealed glass envelope, a combustion-supporting gas in said envelope, a quantity of combustible material located in said envelope, ignition means attached to said envelope and disposed in operative relationship to said combustible material, and a thermoplastic coating of substantially uniform thickness vacuum formed onto the entire exterior surface of said glass envelope and exerting a compressive load thereon.
Claim 2
Dependent Claim
64 words
A photoflash lamp comprising an hermetically sealed glass envelope, a combustion-supporting gas in said envelope, a quantity of combustible material located in said envelope, ignition means attached to said envelope and disposed in operative relationship to said combustible material, and a thermoplastic coating of substantially uniform thickness vacuum formed onto the entire exterior surface of said glass envelope and exerting a compressive load thereon.
Claim 3
Dependent Claim
28 words
A lamp according to claim 1 wherein said coating exerts a compressive load on said glass envelope of form about 1000 to about 4000 pounds per square inch.
Claim 4
Dependent Claim
11 words
A lamp according to claim 1 wherein said coating is clear.
Claim 5
Dependent Claim
24 words
A lamp according to claim 1 wherein said coating comprises a preformed sleeve of thermoplastic material which has been vacuum-formed onto said glass envelope.
Claim 6
Dependent Claim
33 words
A lamp according to claim 1 wherein the coefficient of thermal expansion of said thermoplastic coating is at least about 6 times greater than the coefficient of thermal expansion of said glass envelope.
Claim 7
Dependent Claim
36 words
A lamp according to claim 1 wherein the composition of said coating comprises a light-transmitting thermoplastic selected from the group consisting of acrylic, acrylonitrile-butadiene-styrene, cellulose acetate, ionomers, methylpentene polymer, nylon, polycarbonate, polystyrene, polysulfone, and alloys thereof.
Claim 8
Dependent Claim
19 words
A lamp according to claim 6 wherein the Composition of said coating further includes a small amount of plasticizer.
Claim 9
Dependent Claim
14 words
A lamp according to claim 1 wherein said thermoplastic coating comprises a polycarbonate resin.
Claim 10
Dependent Claim
17 words
A lamp according to claim 8 wherein the thickness of said polycarbonate coating is about 0.020 inch.
Claim 11
Dependent Claim
29 words
A lamp according to claim 1 wherein said combustion-supporting gas in said envelope is at a pressure exceeding one atmosphere, and said combustible material in said envelope is filamentary.
Claim 12
Dependent Claim
60 words
A lamp according to claim 10 wherein said ignition means includes at least one metallic member depending from said glass envelope, and wherein said coating comprises a preformed test tube-shaped sleeve of thermoplastic material having at least one hole in the bottom thereof, which sleeve has been vacuum-formed onto said glass envelope with said metallic member projecting through said hole.
Claim 13
Dependent Claim
18 words
A lamp according to claim 1 wherein the thickness of said coating is at least about 0.020 inch.
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) | 1978-07-07 | 1979-01-06 | 1979-07-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-07-07 | 1983-01-06 | 1983-07-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-07-07 | 1987-01-06 | 1987-07-08 | $7700.00 | Window Closed / Lapsed |