Vehicle headlamp system with series high beam daylight running lamp operation
First Claim
1. A headlamp system for a vehicle with an engine and an ignition switch effective to enable engine operation, the headlamp system comprising, in combination:
- a source of electric power at a predetermined supply voltage;
a pair of headlamps on the front of the vehicle, one on each side thereof;
a headlamp switch having closed and open conditions;
a DRL enabling means;
first circuit means connecting one of the headlamps in series with the headlamp switch and electric power source;
a DRL activating switch effective in a first condition to connect the other of the headlamps in parallel with the one of the headlamps and in a second condition to connect the other of the headlamps in series with the one of the headlamps and the electric power source; and
second circuit means responsive to the ignition switch, headlamp switch and DRL enabling means to put the DRL activating switch in its second condition when the ignition switch is activated, the DRL enabling means is enabled and the headlamp switch is in an open condition, whereby the headlamps are both energized at approximately half the predetermined supply voltage for improved visibility of the vehicle to other vehicle operators, and otherwise to put the DRL activating switch in its first condition, whereby the headlamps may both be energized with the full predetermined supply voltage for illumination of the road for vehicle operation with the headlamp switch in its closed condition.
1 Assignment
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Accused Products
Abstract
A headlamp system provides for the high beam headlamp filaments to be connected in series across the supply voltage for half voltage energization in daytime running lamp operation when the ignition switch is closed, a DRL enabling switch is open and the headlamp switch is not in a headlamp on condition. In normal high beam headlamp operation, the high beam filaments are connected across the supply voltage in parallel for full voltage energization. The DRL enabling switch may be a park brake switch. The headlamp switch may have a fog lamp energizing condition to energize fog lamps; and the system permits such energization when the headlamps are connected in series but not when they are connected in parallel in normal high beam operation. A circuit is provided to sense when one of the high beam filaments is burned out and latch the daytime running light operation off with a signal to the vehicle operator.
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Citations
13 Claims
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1. A headlamp system for a vehicle with an engine and an ignition switch effective to enable engine operation, the headlamp system comprising, in combination:
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a source of electric power at a predetermined supply voltage; a pair of headlamps on the front of the vehicle, one on each side thereof; a headlamp switch having closed and open conditions; a DRL enabling means; first circuit means connecting one of the headlamps in series with the headlamp switch and electric power source; a DRL activating switch effective in a first condition to connect the other of the headlamps in parallel with the one of the headlamps and in a second condition to connect the other of the headlamps in series with the one of the headlamps and the electric power source; and second circuit means responsive to the ignition switch, headlamp switch and DRL enabling means to put the DRL activating switch in its second condition when the ignition switch is activated, the DRL enabling means is enabled and the headlamp switch is in an open condition, whereby the headlamps are both energized at approximately half the predetermined supply voltage for improved visibility of the vehicle to other vehicle operators, and otherwise to put the DRL activating switch in its first condition, whereby the headlamps may both be energized with the full predetermined supply voltage for illumination of the road for vehicle operation with the headlamp switch in its closed condition. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A headlamp system for a vehicle with an engine and an ignition switch effective to enable engine operation, the headlamp system comprising, in combination:
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a source of electric power at a predetermined supply voltage; a pair of headlamps on the front of the vehicle, one on each side thereof, each of the headlamps having a high beam filament; a headlamp switch having closed and open conditions; a DRL activating switch comprising a common terminal, a normally open terminal and a normally closed terminal and being connected in series with the headlamps in series and the electric power source through the common and normally open terminals, the DRL activating switch further comprising an activating means effective only when activated to change the connection of the common terminal from the normally closed terminal to the normally open terminal; a high beam selector switch connected, when in a high beam selected condition, in series with one of the headlamps, the headlamp switch and the electric power source and further in series with the other of the headlamps, the headlamp switch and the electric power source through the common and normally closed terminals of the DRL activating switch; a DRL enabling means; third circuit means effective, unless overridden, to connect the activating means of the DRL activating switch in series with the electric power source for activation of the DRL activating switch when the ignition switch is closed; fourth circuit means responsive to the DRL enabling means to override the third circuit means and prevent activation of the DRL activating switch unless the DRL enabling means is activated; and fifth circuit means responsive to the headlamp switch to override the third circuit means and prevent activation of the DRL activating switch when the headlamp switch is in its closed condition. - View Dependent Claims (8, 9, 10)
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11. A headlamp system for a vehicle with an engine and an ignition switch effective to enable engine operation, the headlamp system comprising, in combination:
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a source of electric power at a predetermined supply voltage across first and second power supply terminals; a headlamp switch; a high beam select switch; first and second headlamps on the front of the vehicle, one on each side thereof, the first headlamp having a high beam filament with one end connected through the high beam select and headlamp switches in series to the first power supply terminal and another end connected to the second power supply terminal; a DRL activating switch comprising a common terminal, a normally open terminal connected to the first power supply terminal and a normally closed terminal connected to the second power supply terminal, the second headlamp having a high beam filament with one end connected to the one end of the high beam filament of the first headlamp to form a junction therebetween and another end connected to the common terminal of the DRL activating switch, the DRL activating switch further comprising an activating means effective only when activated by an electric current therethrough to change the connection of the common terminal from the normally closed terminal to the normally open terminal; a DRL enabling switch connected in series with the ignition switch with a resistive load therebetween, the ends of the ignition and DRL enabling switches not connected to the resistive load being connected respectively to the first and second power supply terminals; a transistor switch having a first conducting terminal connected to the second power supply terminal, a second conducting terminal connected through the activating means of the DRL activating switch to the junction of the ignition switch and resistive load, and a control terminal; first circuit means coupling the electric power source, ignition switch, activating means of the DRL activating switch and transistor switch so as to normally produce conduction of the transistor switch to activate the DRL activating switch when the ignition switch is closed, the first circuit means further coupling the transistor switch to the DRL enabling switch to prevent such conduction of the transistor switch when the DRL enabling switch is closed; a first comparator having a pair of inputs producing activation or no activation thereof and an output coupled to the transistor switch to prevent conduction thereof when the first comparator is activated; a first voltage divider connected across the first and second power supply terminals and effective, when not overridden, to apply a first predetermined voltage to one of the inputs of the first comparator; a second voltage divider connected across the first and second power supply terminals and effective, when not overridden, to apply a second predetermined voltage to the other input of the first comparator effective, relative to the first predetermined voltage, to prevent activation thereof; second circuit means coupling the junction of the headlamp and high beam select switches to the second voltage divider and effective, when the headlamp switch is closed, to override the second voltage divider and apply a third predetermined voltage to the other input of the first comparator, relative to the first predetermined voltage, to cause activation of the first comparator, the second circuit means being further effective, when the headlamp switch is open and the DRL activating switch is activated, to apply a fourth predetermined voltage, intermediate the first and second predetermined voltages, to the other input of the first comparator relative to the first predetermined voltage, to prevent activation of the first comparator. - View Dependent Claims (12, 13)
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Specification