US3783788A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electric detonator free from accidental electrostatic firing
Assignee: NOF Corp
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Filing: 1971-10-07
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Granted: 1974-01-08
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Expires: 1991-10-07
Abstract
Abstract An electric detonator carrying a fuse head disposed in a tube and being fired by an electric current delivered through a pair of legs carried by a plug fitted at an open mouth of the tube. The plug is made of a moldable sealing material having a comparatively low electric resistance, and at least one of the legs is electrically connected to the plug, so as to allow the grounding of the tube through the plug and the leg.
Inventors
- 👤 K Hayashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 15:13
CPC Classifications
F; F42; F42B; F42B3/00; F42B3/10; F42B3/18; F42B3/185
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
176 words
An electric detonator free from accidental electrostatic firing, comprising a tube having a closed bottom and an open mouth, a plug liquid-tightly fitted in the open mouth of the tube in electric contact with the tube, a pair of electrically conductive legs carried by the plug, at least one of the legs being electrically connected to said plug, and a fuse head ball binding the inner ends of the legs located inside the tube through a comparatively high electric resistance, said fuse head being electrically insulated from the tube and made of igniting agent being ignitable upon application of electrical shock through said legs, at least a part of said plug being made of a moldable sealing material with a specific electric resistance of 10 to 105 ohm-cm, said tube being made of a material whose specific resistance is not greater than that of the plug, so as to provide effective resistance between the legs and ground outside the tube which effective resistance is low enough to prevent accidental flashover across the legs and the tube.
Claim 2
Dependent Claim
176 words
An electric detonator free from accidental electrostatic firing, comprising a tube having a closed bottom and an open mouth, a plug liquid-tightly fitted in the open mouth of the tube in electric contact with the tube, a pair of electrically conductive legs carried by the plug, at least one of the legs being electrically connected to said plug, and a fuse head ball binding the inner ends of the legs located inside the tube through a comparatively high electric resistance, said fuse head being electrically insulated from the tube and made of igniting agent being ignitable upon application of electrical shock through said legs, at least a part of said plug being made of a moldable sealing material with a specific electric resistance of 10 to 105 ohm-cm, said tube being made of a material whose specific resistance is not greater than that of the plug, so as to provide effective resistance between the legs and ground outside the tube which effective resistance is low enough to prevent accidental flashover across the legs and the tube.
Claim 3
Dependent Claim
32 words
An electric detonator according to claim 1, wherein said moldable sealing material is selected from the group consisting of natural rubber, synthetic rubber, polyvinyl chloride, polypropylene, polyethylene, polycarbonate, silicone rubber, and polyurethane.
Claim 4
Dependent Claim
28 words
An electric detonator according to claim 2, wherein the moldable sealing material contains an ingredient selected from the group consisting of carbon particles and electrically conductive metallic particles.
Claim 5
Dependent Claim
25 words
An electric detonator according to claim 1, wherein said moldable sealing material for the plug has a specific electric resistance of 102 to 105 ohm-cm.
Claim 6
Dependent Claim
21 words
An electric detonator according to claim 1 and further comprising a base charge disposed in said tube adjacent the closed bottom.
Claim 7
Dependent Claim
20 words
An electric detonator according to claim 5 and further comprising initiating explosive disposed within the tube adjacent the base charge.
Claim 8
Dependent Claim
18 words
An electric detonator according to claim 6 and further comprising an inner cylinder holding said initiating explosive therein.
Claim 9
Dependent Claim
29 words
An electric detonator according to claim 1, wherein each of said legs is lined with a layer of material having a specific electric resistance of 10 to 1010 ohm-cm.
Claim 10
Dependent Claim
61 words
An electric detonator according to claim 1, wherein said legs are lined with electric insulating material, at least one of the legs is partially bared by removing said electric insulating lining at a portion within said plug, so as to cause said bared portion of the leg to come in direct electric contact with the moldable sealing material of the plug.
Claim 11
Dependent Claim
17 words
An electric detonator according to claim 1 and further comprising a holding piece firmly holding said legs.
Claim 12
Dependent Claim
43 words
An electric detonator according to claim 8, wherein said holding piece is made of a material having a specific electric resistance of 10 to 1010 ohm-cm, and at least one of said legs is in direct electric contact with said holding piece material.
Claim 13
Dependent Claim
55 words
An electric detonator according to claim 11, wherein said material for the holding piece consists of a first ingredient selected from the group consisting of natural rubber, synthetic rubber, polyvinyl chloride, polypropylene, polyethylene, polycarbonate, silicone rubber, and polyurethane, and a second ingredient selected from the group consisting of carbon particles and electrically conductive metallic particles.
Claim 14
Dependent Claim
46 words
An electric detonator according to claim 10, wherein said holding piece is made of a moldable sealing material having a specific electric resistance of 10 to 1010 ohm-cm, and said legs are lined with a material whose specific electric resistance is also 10 to 1010 ohm-cm.
Claim 15
Dependent Claim
18 words
An electric detonator according to claim 10, wherein said holding piece is made of an electric insulating material.
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) | 1977-01-07 | 1977-07-09 | 1978-01-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-07 | 1981-07-09 | 1982-01-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-07 | 1985-07-09 | 1986-01-08 | $7700.00 | Window Closed / Lapsed |