US3908509A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fuse and its method of manufacture
Assignee: Ensign Bickford Co
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Filing: 1973-10-29
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Granted: 1975-09-30
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Expires: 1993-10-29
Abstract
Abstract Improved safety is achieved in blasting fuse manufacture by utilizing unincorporated black powder confined within the core of the fuse by fibrillated polypropylene yarn. The unincorporated black powder is produced by premixing the sulfur and charcoal components and separately pregrinding the mixture and the alkali metal nitrate to a particle size of about 45 microns or less. The preground material is then blended immediately prior to its formation into the powder train of the fuse and is enclosed by a number of ribbon-like fibrillated polypropylene yarns which directly contact the powder core and by a number of additional superimposed protective layers. The resultant fuse exhibits uniform cross sectional size and a controlled uniform burning rate.
Inventors
- 👤 Cornelius James Noel Kelly
- 👤 William Clinton Morrow
- 👤 Alvaro Zappalorti
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 13:28
CPC Classifications
C; C06; C06C; C06C5/00
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
124 words
A PROCESS FOR PRODUCING SAFETY FUSE COMPRISING THE STEPS OF PROVIDING AN INTIMATE MIXTURE OF SULFUR AND CHARCOAL HAVING AN AVERAGE PARTICLE SIZE OF LESS THAN 45 MICRONS, PROVIDING ALKALI METAL NITRATE PARTICLES HAVING AN AVERAGE PARTICLE SIZE OF LESS THAN 45 MICRONS, BLENDING THE INTIMATE ADMIXTURE OF SULFUR AND CHARCOAL WITH THE NITRATE PARTICLES WITHOUT SUBJECTING THE BLEND TO SUBSTANTIALLY GRINDING FORCES TO PROVIDE A POWDER BLENDD EXHIBITING FLUID CHARACTERISTICS, FLOWABLE FORMING THE POWDER BLEND INTO A CONTINUOUS POWDER COLUMN AND CONFINING THE COLUMN WITHIN A SPLIT-FILM YARN WRAPPING EXHIBITING A RELATIVELY FLAT RIBBON LIKE CONFIGURATION, SAID WRAPPING BEING IN INTIMATE CONFINING RELATIONSHIP WITH THE POWDER COLUMN AND BEING COMPRISED OF A MULTITUDE OF FLEXIBLE INDIVIDUAL FILAMENTS INTEGRALLY INTERCONNECTED IN A NET-LIKE ARRAY.
Claim 2
Dependent Claim
124 words
A PROCESS FOR PRODUCING SAFETY FUSE COMPRISING THE STEPS OF PROVIDING AN INTIMATE MIXTURE OF SULFUR AND CHARCOAL HAVING AN AVERAGE PARTICLE SIZE OF LESS THAN 45 MICRONS, PROVIDING ALKALI METAL NITRATE PARTICLES HAVING AN AVERAGE PARTICLE SIZE OF LESS THAN 45 MICRONS, BLENDING THE INTIMATE ADMIXTURE OF SULFUR AND CHARCOAL WITH THE NITRATE PARTICLES WITHOUT SUBJECTING THE BLEND TO SUBSTANTIALLY GRINDING FORCES TO PROVIDE A POWDER BLENDD EXHIBITING FLUID CHARACTERISTICS, FLOWABLE FORMING THE POWDER BLEND INTO A CONTINUOUS POWDER COLUMN AND CONFINING THE COLUMN WITHIN A SPLIT-FILM YARN WRAPPING EXHIBITING A RELATIVELY FLAT RIBBON LIKE CONFIGURATION, SAID WRAPPING BEING IN INTIMATE CONFINING RELATIONSHIP WITH THE POWDER COLUMN AND BEING COMPRISED OF A MULTITUDE OF FLEXIBLE INDIVIDUAL FILAMENTS INTEGRALLY INTERCONNECTED IN A NET-LIKE ARRAY.
Claim 3
Dependent Claim
18 words
The process of claim 1 wherein the split-film yarn wrapping is comprised of a fibrillated synthetic plastic tape.
Claim 4
Dependent Claim
30 words
The process of claiM 1 wherein the split-film yarn wrapping is a polyolefin material and the individual filaments within the yarn extend predominantly along the longitudinal dimension of the yarn.
Claim 5
Dependent Claim
23 words
The process of claim 1 wherein the yarn wrapping is a fibrillated zero twist polypropylene yarn having a thickness of about 1-2 mils.
Claim 6
Dependent Claim
25 words
The process of claim 1 wherein the sulfur to charcoal ratio within the mixture falls within the range of from about 4:1 to about 1:4.
Claim 7
Dependent Claim
29 words
The process of claim 1 wherein the blend includes about two parts by weight of nitrate particles and one part by weight of the admixture of sulfur and charcoal.
Claim 8
Dependent Claim
29 words
The process of claim 1 wherein the admixture and the nitrate are separately pulverized prior to blending to result in the average particle size of less than 45 microns.
Claim 9
Dependent Claim
27 words
The process of claim 1 wherein the continuous powder column is formed by flowably feeding the powder blend under agitation with the aid of a center thread.
Claim 10
Dependent Claim
22 words
The process of claim 1 wherein the alkali metal nitrate is selected from the group consisting of potassium nitrate and sodium nitrate.
Claim 11
Dependent Claim
53 words
The process of claim 1 wherein the alkali metal nitrate is potassium nitrate and the powder blend consists essentially of two parts by weight potassium nitrate and one part by weight of the admixture of sulfur and charcoal, the ratio of sulfur to charcoal being within the range of about 1:1 to 3:1.
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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) | 1978-09-29 | 1979-03-31 | 1979-09-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-29 | 1983-03-31 | 1983-09-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-29 | 1987-03-31 | 1987-09-30 | $7700.00 | Window Closed / Lapsed |