US3771249A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electric anti-shark dart
Assignee: Individual
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Filing: 1969-09-04
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Granted: 1973-11-13
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Expires: 1989-09-04
Abstract
Abstract A cylindrically-shaped casing is releasably carried on a spear shaft and houses a source of electric power delivering either a DC or an AC signal to an outwardly extending blade-shaped electrode at one end, and to a plug-shaped electrode on the casing''s opposite end. Upon launching the spear shaft and embedding the blade electrode into a shark or similar marine predator, a concentrically-disposed sleeve mounting a magnet is longitudinally displaced along the casing to actuate a magnetoperated reed switch carried within the casing. In an alternative embodiment a pair of spring-biased contacts are substituted for the reed switch. The contacts extend through the casing and are electrically isolated from each other and the surrounding sea water by a removable insulating cap. An electric current, provided by the source of electric power, passes in a completed circuit from the plug-shaped electrode, through the surrounding seawater, into the shark''s body and returns via the blade-shaped electrode. When sufficient current is present, an involuntary muscular reaction is induced in capacitating the shark without creating noise or bloodying the water that often attracts other sharks.
Inventors
- 👤 C Johnson
- 👤 H Baldridge
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 12:54
CPC Classifications
F; F41; F41B; F41B15/00; F41B15/02; F41B15/04; A; A01; A01K; A01K81/00; F42; F42B; F42B6/00
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
237 words
A self-contained dart for incapacitating a marine predator comprising: a tubularly-shaped casing formed with a cavity and an externally communicating electrically conductive portion sealing one end of said casing and shaped to releasably engage a spear shaft for long range deployment and further formed with a tubular sleeve concentrically disposed about and slidably displaceable along said casing from an extended position to a retracted position; a conductor member mounted on an insulator block sealing the opposite end of said casing electrically insulated from said conductive portion and having an inner terminal disposed in said cavity and an externally reaching elongate blade element substantially enclosed in an electrically insulating sheath having an exposed tip ensuring the passing of an incapacitating current deep within the body of said marine predator and configured to permit its penetration and retention in the fleshy portion of said body; at least one battery providing said current for incapacitating said predator disposed within said cavity connected to provide an internal coupling between said conductive portion and said conductor member; and switching means in the form of a magnet-operated reed switch carried in said cavity and a switching magnet secured to said sleeve disposed for actuating said switch to complete a circuit passing said current from said conductive portion, through surrounding water, through said fleshy portion to said exposed tip causing an incapacitating involuntary reaction thereto, upon embedding said blade member in said marine predator.
Claim 2
Dependent Claim
237 words
A self-contained dart for incapacitating a marine predator comprising: a tubularly-shaped casing formed with a cavity and an externally communicating electrically conductive portion sealing one end of said casing and shaped to releasably engage a spear shaft for long range deployment and further formed with a tubular sleeve concentrically disposed about and slidably displaceable along said casing from an extended position to a retracted position; a conductor member mounted on an insulator block sealing the opposite end of said casing electrically insulated from said conductive portion and having an inner terminal disposed in said cavity and an externally reaching elongate blade element substantially enclosed in an electrically insulating sheath having an exposed tip ensuring the passing of an incapacitating current deep within the body of said marine predator and configured to permit its penetration and retention in the fleshy portion of said body; at least one battery providing said current for incapacitating said predator disposed within said cavity connected to provide an internal coupling between said conductive portion and said conductor member; and switching means in the form of a magnet-operated reed switch carried in said cavity and a switching magnet secured to said sleeve disposed for actuating said switch to complete a circuit passing said current from said conductive portion, through surrounding water, through said fleshy portion to said exposed tip causing an incapacitating involuntary reaction thereto, upon embedding said blade member in said marine predator.
Claim 3
Dependent Claim
210 words
A self-contained dart for incapacitating a marine predator comprising: a tubularly-shaped casing formed with a cavity and an externally communicating electrically conductive portion sealing one end of said casing and shaped to releasably engage a spear for long range deployment; a conductor member mounted on an insulator block sealing the opposite end of said casing electrically insulated from said conductive portion and having an inner terminal disposed in said cavity and an externally reaching elongate blade element substantially enclosed in an electrically insulating sheath having an exposed tip ensuring the passing of an incapacitating current deep within the body of said marine predator and configured to permit its penetration and retention in the fleshy portion of said body; at least one battery providing said current for incapacitating said predator disposed within said cavity connected to provide an internal coupling between said conductive portion and said conductor member; and switching means in the form of a pair of spring-biased contacts extending through said casing separated and electrically isolated by an insulating cap upon the removal thereof enabling the transfer of said current said conductive portion, through surrounding water, through said fleshy portion to said exposed tip causing an incapacitating involuntary reaction thereto, upon embedding said blade member in said marine predator.
Claim 4
Dependent Claim
210 words
A self-contained dart for incapacitating a marine predator comprising: a tubularly-shaped casing formed with a cavity and an externally communicating electrically conductive portion sealing one end of said casing and shaped to releasably engage a spear for long range deployment; a conductor member mounted on an insulator block sealing the opposite end of said casing electrically insulated from said conductive portion and having an inner terminal disposed in said cavity and an externally reaching elongate blade element substantially enclosed in an electrically insulating sheath having an exposed tip ensuring the passing of an incapacitating current deep within the body of said marine predator and configured to permit its penetration and retention in the fleshy portion of said body; at least one battery providing said current for incapacitating said predator disposed within said cavity connected to provide an internal coupling between said conductive portion and said conductor member; and switching means in the form of a pair of spring-biased contacts extending through said casing separated and electrically isolated by an insulating cap upon the removal thereof enabling the transfer of said current said conductive portion, through surrounding water, through said fleshy portion to said exposed tip causing an incapacitating involuntary reaction thereto, upon embedding said blade member in said marine predator.
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) | 1976-11-12 | 1977-05-14 | 1977-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-12 | 1981-05-14 | 1981-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-12 | 1985-05-14 | 1985-11-13 | $7700.00 | Window Closed / Lapsed |