US3858178A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Direction indicator systems for tractor-trailer vehicles
Assignee: Lucas Electrical Co Ltd
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Filing: 1973-09-17
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Granted: 1974-12-31
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Expires: 1993-09-17
Abstract
Abstract A direction indicator system for a tractor-trailer vehicle has at least two lamps on each side of the tractor and at least one lamp on each side of the trailer, together with a direction indicator switch to which power is supplied by an oscillator, the direction indicator switch energising either the left-hand or the right-hand lamps. If two of the lamps fail on one side of the vehicle, the frequency of the oscillator is altered, but if one only of the lamps on one side of the vehicle fails, then one of two pilot lamps in the system is extinguished.
Inventors
- 👤 D Harrison
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:07
CPC Classifications
B; B60; B60Q; B60Q11/00; B60Q11/005; B60Q11/007
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
272 words
A direction indicator system for a tractor-trailer vehicle, comprising at least two left-hand and at least two right-hand direction indicator lamps on the tractor vehicle, at least one left-hand direction indicator lamp and at least one right-hand direction indicator lamp on the trailer vehicle, the left-hand and right-hand direction indicator lamps on the trailer vehicle being connected in parallel with the left-hand and right-hand direction indicator lamps on the tractor vehicle respectively, a direction indicator switch for completing a circuit to either the left-hand or the right-hand direction indicator lamps, a first pilot lamp connected between the circuit to the left-hand and right-hand direction indicator lamps so that when the direction indicator lamps on one side of the vehicle are selected, the first pilot lamp is energised by way of the direction indicator lamps on the other side of the vehicle and flashes in synchronism with the selected direction indicator lamps, an oscillator controlling the supply of power by way of the direction indicator switch to the selected direction indicator lamps, so that the seLected direction indicator lamps flash at a frequency determined by the oscillator, means operable when at least two of the direction indicator lamps selected by the direction indicator switch fail for altering the frequency of said oscillator so that the first pilot lamp flashes at a different frequency, a second pilot lamp, switching means controlled by said oscillator for causing said second pilot lamp to flash in synchronism with the first pilot lamp, and means operable when one of the direction indicator lamps selected by the direction indicator lamps fails for preventing flashing of said second pilot lamp.
Claim 2
Dependent Claim
272 words
A direction indicator system for a tractor-trailer vehicle, comprising at least two left-hand and at least two right-hand direction indicator lamps on the tractor vehicle, at least one left-hand direction indicator lamp and at least one right-hand direction indicator lamp on the trailer vehicle, the left-hand and right-hand direction indicator lamps on the trailer vehicle being connected in parallel with the left-hand and right-hand direction indicator lamps on the tractor vehicle respectively, a direction indicator switch for completing a circuit to either the left-hand or the right-hand direction indicator lamps, a first pilot lamp connected between the circuit to the left-hand and right-hand direction indicator lamps so that when the direction indicator lamps on one side of the vehicle are selected, the first pilot lamp is energised by way of the direction indicator lamps on the other side of the vehicle and flashes in synchronism with the selected direction indicator lamps, an oscillator controlling the supply of power by way of the direction indicator switch to the selected direction indicator lamps, so that the seLected direction indicator lamps flash at a frequency determined by the oscillator, means operable when at least two of the direction indicator lamps selected by the direction indicator switch fail for altering the frequency of said oscillator so that the first pilot lamp flashes at a different frequency, a second pilot lamp, switching means controlled by said oscillator for causing said second pilot lamp to flash in synchronism with the first pilot lamp, and means operable when one of the direction indicator lamps selected by the direction indicator lamps fails for preventing flashing of said second pilot lamp.
Claim 3
Dependent Claim
28 words
A system as claimed in claim 1 in which the oscillator controls a relay winding, the relay winding controlling a contact in series with the direction indicator switch.
Claim 4
Dependent Claim
52 words
A system as claimed in claim 2 in which a resistor is connected across said contact and the potential at the junction of said resistor and the direction indicator switch when the direction indicator switch is closed and the relay contact is open is used to control the frequency of said oscillator.
Claim 5
Dependent Claim
60 words
A system as claimed in claim 3 in which the potential at said junction is used to turn on a transistor which determines the frequency of the oscillator, but if at least two of the direction indicator lamps selected by the direction indicator lamps have failed, the transistor is not turned on, and the frequency of the oscillator is increased.
Claim 6
Dependent Claim
79 words
A system as claimed in claim 3 in which said means operable when one of the direction indicator lamps selected by the direction indicator switch fails for preventing flashing of said second pilot lamp comprises a capacitor which is charged by the potential at said junction, the potential across said capacitor serving when the relay contact closes to hold off the second pilot lamp if one of the direction indicator lamps selected by the direction indicator switch has failed.
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) | 1977-12-30 | 1978-07-01 | 1978-12-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-30 | 1982-07-01 | 1982-12-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-30 | 1986-07-01 | 1986-12-31 | $7700.00 | Window Closed / Lapsed |