US 3733515 A
A vehicle lighting system has a dip switch which is connected to the vehicle battery through the vehicle lighting switch, and which operates a current sensing element. This current sensing element controls a changeover contact which in one position energizes the main beam filament and in the other position energizes the dip beam filament. The system incorporates devices for energizing an alternative headlamp if the selected headlamp filament fails.
Description (OCR text may contain errors)
Unite ttes atet 11 1 Parkes 1 May 15, 1973 1541 LIGHTING SYSTEMS FOR ROAD 3,479,557 ll/l969 Schultz ..3l5/83 VEHICLES 2,023,954 12 1935 Hagar et al... ....315 83 2,100,695 11 I937 L k .315 83 [761 memo Eric Bernard Park, 25 Langleys 2 172 903 9l1939 Chzrgihg ms/s; .x Road Selly Brmmgham 2,223,251 11 1940 Hack ..3l5/83 gland 2,907,920 10 1959 Mellvaine ..315/83  Filed: June 28, 1971 Primary ExaminerRoy Lake  Appl' 157449 Assistant Examiner lames B. Mullins Attorney-Holman & Stern  Foreign Application Priority Data June 27, 1970 Great Britain ..31,286/70  ABSTRACT A vehicle lighting system has a dip switch which is  US. Cl ..3l5/83 ted to the vehicle battery through the vehicle  Int. Cl. ..B60q 1/14 lighting switch, and which operates a current Sensing  Field of Search ..315/82, 83 element This current Sensing element controls a Chan geover contact which in one position energizes the  References C'ted main beam filament and in the other position ener- UNITED STATES PATENTS gizes the dip beam filament/The system incorporates devices for energizing an alternative headlamp if the 3,532,929 10/1970 Schultz ..315/83 Selected headlamp filament fails 2,540,410 2/1951 Wagner ..3l5/83 1 Claim, 1 Drawing Figure 29 Zia 1 LHGHTING SYSTEMS FOR ROAD CLES This invention relates to lighting systems for road vehicles.
A system according to the invention comprises in combination first and second terminals for connection to a source of current, a supply line connected to the first terminal through the vehicle lighting switch, a twoposition dip switch having a movable contact, connected to the second terminal, the dip switch serving in one position to complete a circuit from the second terminal to the supply line through a current sensing element which operates a changeover contact which in one position completes a first circuit connecting the supply line to the second terminal through a main beam filament, and in its other position completes a second circuit connecting the supply line to the second tenninal through a dipped beam filament.
The accompanying drawing is a circuit diagram illustrating one example of the invention.
Referring to the drawing a road vehicle includes a battery 11 having its negative terminal earthed, and its positive terminal connected to the movable contact 12 of a lighting switch. The battery is charged in the usual way by a generator driven by the engine, the output of the generator being controlled by a conventional voltage regulator. The lighting switch is movable from the off position shown to a first operative position in which it completes a circuit to a contact 13 connected to the side and tail lamps of the vehicle, and a second position in which it still completes the circuit to the contact 13, but also completes a circuit to a contact 14 to operate the vehicle headlamps in a manner to be described.
The system further includes a dip switch having a movable contact 15 which is earthed and which in the main beam and dipped beam positions of the switch engages contacts 16 and 17 respectively. The contact 16 is connected to the terminal 14 through a main beam warning lamp 18, whilst the contact 17 is connected to the terminal 14 through the winding 19 of a relay having four contacts 19a, 19b, 19c and 19d. All four of these contacts are shown in the position they assume when the winding 19 is not energized.
The contact 19a is connected to the terminal 14 through the winding 21 of a relay, and is movable between the position shown in which it engages a contact 23, and a second position in which it engages a contact 24. The contact 19d is connected to the terminal 14 through the winding 22 of a further relay, and is movable from engagement with a terminal 25 into engagement with a contact 26. The contacts 23 and 25 are connected through fuses 27 and 32 respectively to one side of each of the main beam filaments 28 and 33 of the vehicle headlamps, whilst the contacts 24 and 26 are connected through fuses 29 and 34 respectively to one side of each of the dipped beam filaments 31 and 35. The other sides of all four filaments 28, 31, 33 and 35 are earthed. The contacts 24 and 23 are interconnected through a resistor 41 in series with a normally closed contact 21a operable by the winding 21, whilst the contacts 25 and 26 are interconnected through a resistor 42 and a normally closed contact 22a operable by the winding 22.
The system further includes four warning lamps 36, 37, 38 and 39. The contacts 19b and 19c are interconnected and earthed, and when the winding 19 is not energized, the contacts 19b and 19c are in the position shown where they connect the terminals 24 and 26 respectively to earth by way of the lamps 36 and 38. When the winding 19 is energized, the contacts 19b and 13c connect the terminals 23 and 25 to earth through the lamps 37 and 39 respectively. When their respective filaments 31, 28, 35, 33 are operating satisfactorily, insufficient current flows through the filaments 36, 37, 38, 39 to illuminate them.
Assuming that the system is operating satisfactorily, and that the switch 15 is in the position shown, then when the contact 12 is moved into engagement with the contact 14, the lamp 18 is illuminated to indicate that the main beam is energized. Current flows from the terminal 14 by way of the winding 21, contacts 19a and 23 and the fuse 27 to energize the filament 28 and the winding 21, so that the contact 21a is open. There is an initial flow of current through the contact 21a and resistor 41 and thence by way of the fuse 29 to the filament 31, but this current only lasts for a short while whilst the winding 21 operates to open the contact 21a, and does not illuminate the filament 31. The filament 33 is illuminated at the same time as the filament 28, and the winding 22 is energized to hold the contact 22a open.
If either of the filaments 28, 33 fail while the circuit is in the condition shown in the drawing, then, assuming for example that the filament 28 fails, the circuit to the winding 21 is broken, and the contact 21a closes, so that the filament 31 is energized at reduced intensity by way of the winding 21, contact 23, contact 21a and resistor 41, so as to replace the filament 28. The current flowing through the winding 21 is insufficient to open the contact 21a, which therefore remains closed. The driver is given an indication that the filament 28 has failed by illumination of the lamp 36.
If the filament 33 fails, then the filament 35 is brought into operation at reduced intensity, and the lamp 38 is illuminated.
When the dip switch 15 is operated, so that it engages the contact 17, the lamp 18 is extinguished and the winding 19 is energized. The contacts 19a, 19b, 19c and 19d move to their alternative positions, and the dipped beam filaments 31 and 35 are energized.
If the filament 31 fails with the circuit in the dipped beam condition, then the filament 28 is energized at reduced intensity, and the lamp 37 is illuminated. Similarly, failure of the filament 35 results in illumination of the filament 33, at reduced intensity and illumination of the warning lamp 39.
1. A lighting system for a road vehicle having a dipped beam headlamp filament and a main beam headlamp filament, comprising a battery having a live terminal and a grounded terminal, switch means for selecting the clipped beam filament or the main beam filament, said switch means comprising first and second fixed contacts and a movable contact, a circuit connecting said first fixed contact to ground through said dipped beam filament, a circuit connecting said second fixed contact to ground through said main beam filament, a series circuit connecting said movable contact to the live terminal of said battery, said series circuit including a relay winding and a lighting switch on the vehicle, and a circuit interconnecting the fixed contacts of said switch means and including in series a resistor and a normally closed contact operable by said relay winding.