US3764971A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electric alarm device
Assignee: Individual
•
Filing: 1971-08-19
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Granted: 1973-10-09
•
Expires: 1991-08-19
Abstract
Abstract An electric alarm system, particularly for boats, having an alarm sensing circuit connected to an alarm contact circuit which is adapted to be mounted on the boat. The connection between the alarm sensing circuit and the alarm contact circuit comprises an inductive coupling link in the form of a transformer having primary and secondary windings which are mechanically detachable from each other.
Inventors
- 👤 G Brobeck
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 09:52
CPC Classifications
G; G08; G08B; G08B13/00; G08B13/22; B; B63; B63B; B63B17/00; B63B2017/0009
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
181 words
An electric burglary alarm system for watercraft for transmitting alarm information from a watercraft to a shore-based alarm, comprising in combination: a shore-based alarm state sensing circuit means including an alarm; an alarm contact circuit means adapted to be mounted on the watercraft to be protected; connection means between the alarm state sensing circuit means and the alarm contact circuit means and separable for actuating said alarm upon theft of said watercraft; said connection means transforming the impedance value of the alarm contact circuit means for electrical operation with the alarm state sensing circuit means, said connection means comprising an inductive coupling link defining a transformer having primary and secondary windings which are mechanically detachable from each other, said alarm contact circuit means comprising means defining a normally closed contact openable for operating said alarm in response to burglary on said watercraft and connected in closed circuit loop with said secondary winding, said alarm staTe sensing circuit means being connected to said primary winding; whereby said alarm is responsive to both opening of said contact and separation of said connection means.
Claim 2
Dependent Claim
181 words
An electric burglary alarm system for watercraft for transmitting alarm information from a watercraft to a shore-based alarm, comprising in combination: a shore-based alarm state sensing circuit means including an alarm; an alarm contact circuit means adapted to be mounted on the watercraft to be protected; connection means between the alarm state sensing circuit means and the alarm contact circuit means and separable for actuating said alarm upon theft of said watercraft; said connection means transforming the impedance value of the alarm contact circuit means for electrical operation with the alarm state sensing circuit means, said connection means comprising an inductive coupling link defining a transformer having primary and secondary windings which are mechanically detachable from each other, said alarm contact circuit means comprising means defining a normally closed contact openable for operating said alarm in response to burglary on said watercraft and connected in closed circuit loop with said secondary winding, said alarm staTe sensing circuit means being connected to said primary winding; whereby said alarm is responsive to both opening of said contact and separation of said connection means.
Claim 3
Dependent Claim
70 words
An electric alarm system according to claim 1, wherein the alarm state sensing circuit means includes a balance bridge circuit having a potential source connected thereacross, said alarm being connected to the bridge circuit and means connecting said primary winding of said transformer in a leg of said bridge for unbalancing said bridge in response to either separation of secondary winding from said primary winding or opening of said contact.
Claim 4
Dependent Claim
53 words
An electric alarm system according to claim 2, including an impedance member connected in series with said contact in said closed circuit loop and selected so as to define with the coupled primary and secondary windings an impedance value which balances said bridge circuit with said contact closed and maintains said alarm unenergized.
Claim 5
Dependent Claim
51 words
An electric alarm system according to claim 8, wherein the transformer includes a core on which said primary winding is wound, said core having a pair of opposed, spaced portions defining an air gap, said secondary winding being removably receivable in said air gap between said spaced portions of said core.
Claim 6
Dependent Claim
25 words
An electric alarm system according to claim 4, wherein the core on which the primary winding is mounted is made of a magnetically conductive material.
Claim 7
Dependent Claim
139 words
An electric alarm system according to claim 4, wherein one said core portion is a substantially cup-shaped casing and the other core portion extends plug-like from the bottom of said cup-shaped portion axially toward the open end of said cup-shaped portion and is spaced by said air gap from the peripheral wall of said cup-shaped portion, said air gap being annular, said primary winding being wound on the radially inner of said core portions facing outwardly toward said air gap, said transformer further including a socket member of cup-like configuration having a peripheral wall, said secondary winding being on the inside of said peripheral wall, said socket member and secondary winding being receivable axially within said air gap of said core with said secondary winding in radially opposed surrounding relation to said primary winding for rendering said transformer operative.
Claim 8
Dependent Claim
24 words
An electric alarm system according to claim 6 in which said windings are embedded in a protective material to shield same against mechanical damage.
Claim 9
Dependent Claim
71 words
An electric alarm system according to claim 4 in which said core is substantially U-shaped, having a bight portion on which said primary winding is wound and spaced opposed legs extending therefrom and defining said air gap between the opposed free ends thereof, said secondary winding comprising a relatively flat coil oriented transverse of the plane of said core and receivable between said free leg ends for rendering said transformer operative.
Claim 10
Dependent Claim
29 words
An electric alarm system according to claim 8, in which said secondary winding coil is of only a single turn; consisting of a U-shaped conductor receivable in said gap.
References Cited (Backward Citations)
US3087886A
Cited
US3540024A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-10-08 | 1977-04-09 | 1977-10-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-08 | 1981-04-09 | 1981-10-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-08 | 1985-04-09 | 1985-10-09 | $7700.00 | Window Closed / Lapsed |