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Patent US3741124A successfully refreshed from Google Patents.
US3741124A
Expired / Lapsed
US
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Demolition firing device
Assignee: United States Department of the Navy
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Filing: 1971-05-11
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Granted: 1973-06-26
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Expires: 1991-05-11
Abstract
Abstract A firing device is sympathetically activated by the pressure wave generated by a nearby air or underwater explosion. When activated, the firing device detonates a main charge to which it is attached and the resultant shock wave initiates a similar firing device in cain reaction fashion. An incoming pressure wave is converted into an electrical signal by a hydrophone, amplified by an FET amplifier, and level detected by a programmable unijunction transistor. If the pressure wave is above a predetermined amplitude, the programmable unijunction transistor conducts, causing an SCR to become conductive. This allows a firing capacitor to discharge through an explosive primer, which in turn detonates a main charge. The firing device also includes delay arming circuitry and self-destruct circuitry.
Inventors
- 👤 F Visk
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 10:06
CPC Classifications
F; F42; F42D; F42D1/00; F42D1/04; F42D1/045; F42D1/05; F42C; F42C11/00
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
128 words
A demolition firing device comprising: transducer means for transducing pressure signals into electrical signals; means coupled to said transducing means for filtering and amplifying said electrical signals; level detecting means coupled to said filtering and amplifying means for generating an output pulse whenever the output of said filtering and amplifying means exceeds a predetermined variable voltage amplitude; firing means connectable to an electrically activated explosive primer and coupled to said level detecting means for supplying a firing pulse to said explosive primer in response to said output pulse; and electromechanical arming delay switch means connectable to a source of electrical potential connected for applying said electrical potential to said filtering and amplifying means, said level detecting means, and said firing means after a first predetermined period of time.
Claim 2
Dependent Claim
128 words
A demolition firing device comprising: transducer means for transducing pressure signals into electrical signals; means coupled to said transducing means for filtering and amplifying said electrical signals; level detecting means coupled to said filtering and amplifying means for generating an output pulse whenever the output of said filtering and amplifying means exceeds a predetermined variable voltage amplitude; firing means connectable to an electrically activated explosive primer and coupled to said level detecting means for supplying a firing pulse to said explosive primer in response to said output pulse; and electromechanical arming delay switch means connectable to a source of electrical potential connected for applying said electrical potential to said filtering and amplifying means, said level detecting means, and said firing means after a first predetermined period of time.
Claim 3
Dependent Claim
14 words
The demolition firing device of claim 1, wherein said transducer means comprises a hydrophone.
Claim 4
Dependent Claim
34 words
The demolItion firing device of claim 1, wherein said filtering and amplifying means comprises; a low pass filter coupled to said transducer means; and means for amplifying the output of said low pass filter.
Claim 5
Dependent Claim
61 words
The demolition firing device of claim 3, wherein said amplifying means comprises: a resistor deivider network coupled across the output of said low pass filter and providing a plurality of output signals; switching means for selecting any one of said plurality of output signals; and a field effect transistor amplifier for amplifying said selected one of said plurality of output signals.
Claim 6
Dependent Claim
59 words
The firing device of claim 1, wherein said level detecting means comprises: a programmable unijunction transistor having its gate coupled to the output of said filtering and amplifying means and producing said output pulse at its cathode; and means for biasing the anode of said programmable unijunction transistor to a selectable potential to establish said predetermined variable voltage amplitude.
Claim 7
Dependent Claim
32 words
The demolition firing device of claim 5, wherein said biasing means includes a variable resistance connected to the anode of said programmable unijunction transistor and connectable to a source of reference potential.
Claim 8
Dependent Claim
114 words
The demolition firing device of claim 1, wherein said firing means comprises: a silicon controlled rectifier having its gate coupled to the output of said level detecting means, having its cathode connectable to said explosive primer, and having its anode connectable to said source of electrical potential; a firing capacitor connected to the anode of said silicon controlled rectifier and connectable to a source of reference potential; anti-tampering means for connecting the gate of said silicon controlled rectifier to said source of electrical potential in response to physical movement of said demolition firing device; and self-destruct means for directly discharging said firing capacitor through said explosive primer after a second predetermined period of time.
Claim 9
Dependent Claim
26 words
The demolition firing device of claim 7, wherein said antitampering means comprises a trembler switch connected between the anode and gate of said silicon controlled rectifier.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-06-25 | 1976-12-25 | 1977-06-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-25 | 1980-12-25 | 1981-06-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-25 | 1984-12-25 | 1985-06-26 | $7700.00 | Window Closed / Lapsed |