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Patent US3808731A successfully refreshed from Google Patents.
US3808731A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic down rigger
Assignee: Navico Inc
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Filing: 1973-01-15
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Granted: 1974-05-07
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Expires: 1993-01-15
Abstract
Abstract In trolling a lake for fish it is desirable to troll at a depth where the temperature is ideal for the species of fish being sought. This abstract describes an apparatus in which a temperature sensor is carried in a probe attached to a cable depending from a motor driven reel carried by the trolling boat. The temperature sensor is a thermo-resistive element which is connected to a servo amplifier which controls the direction of rotation of the reel, so that the probe cable can be lengthened to permit the probe to go to a greater depth or can be shortened to bring the probe to a shallower depth, so as to adjust the position of the probe to water of the desired temperature.
Inventors
- 👤 D Lowrance
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 05:48
CPC Classifications
A; A01; A01K; A01K91/00; A01K91/06; A01K91/08
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
136 words
An automatic fish line downrigger comprising: a. temperature sensing means; b. housing means for housing said temperature sensor, said housing of negative buoyancy; c. tensile means connecting said housing means to a motor driven reel means on a boat, said boat adapted to tow said housing through the water; d. fish hook means connected to said housing means; and e. electrical conductor means connected from said sensing means in said housing means to servo amplifier means and means connecting said servo amplifier means to motor means for driving said reel means; whereby said motor means is responsive to said servo amplifier means which is responsive to said temperature sensor and will control the length of said tensile means to permit said housing to seek a depth of immersion in which the water is a preselected temperature.
Claim 2
Dependent Claim
136 words
An automatic fish line downrigger comprising: a. temperature sensing means; b. housing means for housing said temperature sensor, said housing of negative buoyancy; c. tensile means connecting said housing means to a motor driven reel means on a boat, said boat adapted to tow said housing through the water; d. fish hook means connected to said housing means; and e. electrical conductor means connected from said sensing means in said housing means to servo amplifier means and means connecting said servo amplifier means to motor means for driving said reel means; whereby said motor means is responsive to said servo amplifier means which is responsive to said temperature sensor and will control the length of said tensile means to permit said housing to seek a depth of immersion in which the water is a preselected temperature.
Claim 3
Dependent Claim
25 words
The downrigger as in claim 1 in which said tensile means comprises a cable including electrical conductors for transmitting the output signal of said sensor.
Claim 4
Dependent Claim
26 words
The downrigger as in claim 1 in which said servo amplifier includes a resistanCe bridge input in which said sensor comprises one leg of said bridge.
Claim 5
Dependent Claim
21 words
The downrigger as in claim 1 including switch means to reverse the direction of response of said motor to said sensor.
Claim 6
Dependent Claim
15 words
The downrigger as in claim 1 including manual override means to reel in said housing.
Claim 7
Dependent Claim
16 words
The downrigger as in claim 1 including fish line means from said boat to said housing.
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) | 1977-05-06 | 1977-11-05 | 1978-05-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-06 | 1981-11-05 | 1982-05-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-06 | 1985-11-05 | 1986-05-07 | $7700.00 | Window Closed / Lapsed |