US3740648A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Distress call signalizer of the miniature transmitter type
Assignee: Individual
•
Filing: 1971-10-27
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Granted: 1973-06-19
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Expires: 1991-10-27
Abstract
Abstract A distress signal transmitter circuit comprising a positionsensitive mercury switch, and a pressure-sensitive mechanical switch, coupled in parallel to a transmitter and a power supply. A continuously charging-discharging capacitor, coupled to the power supply and the transmitter, causes the generation and transmission of signals at predetermined intervals. Displacement of the mercury switch or pressure on the mechanical switch, interrupts the transmission of the signals at the predetermined intervals and causes a continuous signal to be transmitted by the circuit, thus indicating a distress condition.
Inventors
- 👤 A Grotjahn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 18:55
CPC Classifications
G; G08; G08B; G08B21/00; G08B21/02; G08B21/04; G08B21/0438; G08B21/0446; G08B21/0297; G08B23/00
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
151 words
A distress call signalling circuit, for transmitting a distress signal to a remote receiver which detects the distress signal and generates an alarm, comprising: a battery; a transmitter, having one of its terminals coupled to said battery, for generating a signal at a specified frequency; a capacitor, having a predetermined breakdown voltage,coupled at one end to said battery and at the other end to the other one of said transmitter terminals; a mercury switch, coupled in parallel to said capacitor, and having at least two contacts, one of said contacts being coupled to said transmitter and the other of said contacts being coupled to said battery; and a pressure-sensitive mechanical switch, coupled in parallel to said capacitor, and including a stationary contact and a pair of movable pressure-sensitive contacts diposed adjacent said stationary contact, said stationary contact being coupled to said battery, and said movable contacts being coupled to said transmitter.
Claim 2
Dependent Claim
151 words
A distress call signalling circuit, for transmitting a distress signal to a remote receiver which detects the distress signal and generates an alarm, comprising: a battery; a transmitter, having one of its terminals coupled to said battery, for generating a signal at a specified frequency; a capacitor, having a predetermined breakdown voltage,coupled at one end to said battery and at the other end to the other one of said transmitter terminals; a mercury switch, coupled in parallel to said capacitor, and having at least two contacts, one of said contacts being coupled to said transmitter and the other of said contacts being coupled to said battery; and a pressure-sensitive mechanical switch, coupled in parallel to said capacitor, and including a stationary contact and a pair of movable pressure-sensitive contacts diposed adjacent said stationary contact, said stationary contact being coupled to said battery, and said movable contacts being coupled to said transmitter.
Claim 3
Dependent Claim
63 words
The circuit as recited in claim 1, further comprising a second battery, coupled in parallel to said first battery, and a switching member, coupled in series with said first and second batteries, and responsive to the voltage output of said first battery, for coupling said transmitter to said second battery when said voltage output of said first battery falls below a predetermined level.
Claim 4
Dependent Claim
14 words
The circuit as recited in claim 2, wherein said switching member comprises a relay.
Claim 5
Dependent Claim
17 words
The circuit as recited in claim 1, wherein said mercury switch comprises a mercury toroid tube switch.
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) | 1976-06-18 | 1976-12-18 | 1977-06-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-18 | 1980-12-18 | 1981-06-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-18 | 1984-12-18 | 1985-06-19 | $7700.00 | Window Closed / Lapsed |