Patent US3903464A successfully refreshed from Google Patents.
US3903464A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Braking device for aircraft gyroscope
Assignee: Individual
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Filing: 1974-07-26
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Granted: 1975-09-02
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Expires: 1994-07-26
Abstract
Abstract The invention provides means for electronically braking gyroscope rotation and for reducing the normal unbraked rundown time of an aircraft''s gyroscope driving motor. The devices disclosed provide for temporary application of DC current from the aircraft battery to the stator of the gyroscope drive motor. This is automatically accomplished with a fail safe circuit which connects one polarity DC voltage from the aircraft battery to two of the three phase windings of the gyroscope drive motor stator and the other polarity of DC voltage to the third winding. A direct current produced magnetic field is thus set up in the stator windings. The spinning rotor (during rundown) interacts with the magnetic field in accordance with Lenz''s Law and dynamic braking of the gyroscope is accomplished.
Inventors
- 👤 Edwin B Lyon
- 👤 Jeff R Bailey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 22:13
CPC Classifications
H; H02; H02P; H02P3/00; H02P3/06; H02P3/18; H02P3/24
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
316 words
In combination with an aircraft gyroscope system having a three phase gyroscope drive motor, a three phase AC power source and a drive motor power switch for connecting and disconnecting the stator windings of said gyroscope drive motor to and from said three phase AC power source, means for automatically dynamically braking said gyroscope drive motor in response to each disconnection of said stator windings from said three phase AC power source comprising a source of DC power, and a circuit for connecting, for a fixed period of time following each disconnection of AC power, said source of DC power to the three drive motor stator terminals, the DC power applied to two of the stator terminals being of opposite polarity to the DC power applied to the third stator terminal, said circuit comprising a first relay having an energization coil and normally open and normally closed contacts, said drive motor stator being connected to the three phase AC power source through said normally open contacts and to said source of DC power through said normally closed contacts, a DC power switch adapted to open when said drive motor power switch closes and to close when said drive motor power switch opens, a second relay having an energization coil and normally open and normally closed contacts, said second relay energization coil, a normally closed contact of said first relay, a normally open contact of said second relay, and said DC power switch being connected in series between the positive and negative terminals of said source of DC power, a silicon controlled rectifier connected in series with said first relay energization coil between the negative terminal of said source of DC power and the normally closed terminals of said first relay, and a parallel RC timing circuit connected between the cathode gate of said silicon controlled rectifier and the negative terminal of said source of DC power.
Claim 2
Dependent Claim
316 words
In combination with an aircraft gyroscope system having a three phase gyroscope drive motor, a three phase AC power source and a drive motor power switch for connecting and disconnecting the stator windings of said gyroscope drive motor to and from said three phase AC power source, means for automatically dynamically braking said gyroscope drive motor in response to each disconnection of said stator windings from said three phase AC power source comprising a source of DC power, and a circuit for connecting, for a fixed period of time following each disconnection of AC power, said source of DC power to the three drive motor stator terminals, the DC power applied to two of the stator terminals being of opposite polarity to the DC power applied to the third stator terminal, said circuit comprising a first relay having an energization coil and normally open and normally closed contacts, said drive motor stator being connected to the three phase AC power source through said normally open contacts and to said source of DC power through said normally closed contacts, a DC power switch adapted to open when said drive motor power switch closes and to close when said drive motor power switch opens, a second relay having an energization coil and normally open and normally closed contacts, said second relay energization coil, a normally closed contact of said first relay, a normally open contact of said second relay, and said DC power switch being connected in series between the positive and negative terminals of said source of DC power, a silicon controlled rectifier connected in series with said first relay energization coil between the negative terminal of said source of DC power and the normally closed terminals of said first relay, and a parallel RC timing circuit connected between the cathode gate of said silicon controlled rectifier and the negative terminal of said source of DC power.
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) | 1978-09-01 | 1979-03-03 | 1979-09-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-01 | 1983-03-03 | 1983-09-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-01 | 1987-03-03 | 1987-09-02 | $7700.00 | Window Closed / Lapsed |