US3730097A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fuze for use in firedamp-endangered and coal-dust-endangered operations
Assignee: Dynamit Nobel AG
•
Filing: 1971-10-28
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Granted: 1973-05-01
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Expires: 1991-10-28
Abstract
Abstract A fuze for use in firedamp and coal-dust endangered operations suitable for use in the longhole blasting technique which includes a hollow tube, an explosive core of desensitized explosive surrounding the hollow tube, a wound strip of plastic encasing the explosive core, a multiple-layer spun casing of fibers enclosing the wound plastic strip and an envelope of inert substances surrounding the multiple-layer spun casing. The envelope is, preferably, a mixture of a polymer and insert substances covered, respectively, by cellulose-base fibers, a wound strip of plastic, a multiple-layer spun envelope of fibers, and finally a waterproof outer shell of synthetic resin.
Inventors
- 👤 W Helfgeni
- 👤 W Rohde
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 21:40
CPC Classifications
C; C06; C06C; C06C5/00; C06B; C06B25/00; C06B25/32; C06C5/04; C06C5/06
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
22 words
A fuze according to claim 1 wherein said explosive is present in an amount of between about 2 and about 5 g./m.
Claim 2
Dependent Claim
27 words
A fuze according to claim 1 wherein said explosive is pulverized penthrite, at least 60 percent of which passes through a screen mesh of about 0.074 mm.
Claim 3
Dependent Claim
45 words
A fuze according to claim 1 wherein said explosive is desensitized by a substance selected from the group consisting of cryolite, halogenides, sulfates, bicarbonates, and carbonates of the alkali and alkaline earth metals, the corresponding ammonium salts, and all oxides of the alkaline earth metals.
Claim 4
Dependent Claim
24 words
A fuze according to claim 4 wherein 10 percent by weight of cryolite based on the weight of explosive is added to said explosive.
Claim 5
Dependent Claim
19 words
A fuze according to claim 1 wherein said hollow tube is constructed of a flexible, dimensionally stable synthetic resin.
Claim 6
Dependent Claim
24 words
A fuze according to claim 6 wherein the diameter of said hollow tube is about one-third of the outside diameter of said explosive core.
Claim 7
Dependent Claim
57 words
A fuze according to claim 1 wherein said casing is comprised of a mixture of at least one powdery synthetic resin and at least one substance selected from the group consisting of cryolite, halogenides, sulfates, bicarbonates, and carbonates of the alkali and alkaline earth metals, the corresponding ammonium salts, and all oxides of the alkaline earth metals.
Claim 8
Dependent Claim
28 words
A fuze according to claim 8 wherein between about 5 percent and about 70 percent of synthetic resin particles are admixed with said at least one inert substance.
Claim 9
Dependent Claim
21 words
A fuze according to claim 8 wherein said at least one synthetic resin is based on polyacrylonitrile with styrene and butadiene.
Claim 10
Dependent Claim
19 words
A fuze according to claim 1 further comprising an outer shell of extruded synthetic resin disposed around said casing.
Claim 11
Dependent Claim
24 words
A fuze according to claim 1 further comprising a strip of wound plastic disposed between said explosive core and said casing of inert substances.
Claim 12
Dependent Claim
30 words
A fuze according to claim 12 further comprising a multiple-layer spun envelope of synthetic or natural threads positioned between said strip of wound plastic and said casing of inert substances.
Claim 13
Dependent Claim
20 words
A fuze according to claim 13 further comprising a second strip of wound plastic covering said casing of inert substances.
Claim 14
Dependent Claim
25 words
A fuze according to claim 14 further comprising a second multiple-layer spun envelope of synthetic or natural threads encasing said second strip of wound plastic.
Claim 15
Dependent Claim
22 words
A fuze according to claim 15 further comprising an outer shell of extruded synthetic resin disposed around said second multiple-layer spun envelope.
Claim 16
Dependent Claim
33 words
A fuze according to claim 16 further comprising first and second thread groups, respeCtively, wound in a manner so as to guide the distribution of said powdery desensitized explosive and said inert substances.
References Cited (Backward Citations)
US2380312A
Cited
US2891475A
Cited
US3027839A
Cited
US3344005A
Cited
US3590739A
Cited
DE1916685A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-30 | 1976-10-30 | 1977-05-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-30 | 1980-10-30 | 1981-05-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-30 | 1984-10-30 | 1985-05-01 | $7700.00 | Window Closed / Lapsed |