EMERGENCY LIGHT

Abstract: A flashing light system comprising a discharge light source (94), a circuit which has capacitors (88) and a firing device (92) for discharging the capacitors (88) through the light source. A circuit (63) is provided to charge the capacitors (88) to a voltage level that can supply a high current short duration flash, and a triggering device (53) is connected to the firing device (92) which generates a trigger signal in a predetermined sequence.

Description: - / - mERG GT LIGHT This invention relates to flashing light systems which may be used as emergency or warning lights. For the sake of convenience, the invention will be described in relation to emergency lights for vehicles such as police cars, ambulances and tow trucks but it is to be understood that the invention is not limited thereto as the system may be applied to other areas such as road obstruction lights and the like. BACKGROUND ART. Hitherto, emergency lights fitted to motor vehicles have been based on the fixed globe/spinning reflector system. Such prior art systems suffer from a number of disadvantages associated with the rotating components. Furthermore, such systems draw about 5 amps to energize the globe and spinning means and thus prolonged operation is not possible without the motor of the vehicle running. It is an object of the present invention to provide a flashing light system suitable for use as an emergency vehicular light that draws less power relative to the duration and intensity of light flash than lights made in accordance with the prior art. Typically, the light in accordance with the present invention draws approximately 1.8 amps as opposed to 5 amps of the known systems. It is a further object of the present invention to provide a reliable flashing light system that does not use moving components or filament. DISCLOSURE OF INVENTION. According to the invention there is provided a flashing light system comprising:- (i) a discharge light source, (ii) a first circuit for the light source having capacitance means and firing means for coupling the capacitance to the light source so that it discharges therethrough, (iii) a second circuit for providing a voltage to charge the capacitance means to a level which when the capacitance means is coupled to the light source will provide a high current short duration arc or flash, and, O PI H IPO (iv) triggering means for a generating trigger signal which is supplied in a pre-determined sequence to the firing means so that the light source will flash in a pre¬ determined sequence and the second circuit will recharge the capacitance means so that the flashing sequence will be repeated. BRIEF DESCRIPTION OF DRAWINGS. In order that the invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings in which:- Fig. 1 is a schematic diagram of a flashing l ght system according to one embodiment of the invention, Fig. 2 is a circuit diagram of the main controller for the flashing light system shown in Fig. 1, Fig. 3 is a circuit diagram of the power supply and sequence controller of the flashing light system shown in Fig. 1, Fig. 4 is a circuit diagram of the charging, firing and flashing portions of the system shown in Fig. 3, Fig. 5 is a schematic diagram of a flashing light system according to a second embodiment of the invention, Fig. 6 is a circuit diagram of the sequence controller of the system shown in Fig. 5, and, Fig. 7 is a circuit diagram of the power supply, firing and flashing portions of the system shown in Fig. 5. BEST MODE OF CARRYING OUT INVENTION: The flashing light system shown in Fig. 1 includes a main controller 10 adapted to be connected to the battery of a vehicle, a power supply and ■__. O H- sequence controller 11 and a plurality of light sources 12 mounted in boxes 13, 14, 15 and 16 on the left hand side of the power supply and sequence controller 11 and in boxes 17, 18, 19 and 20 on the right hand side of the controller 11. The light source boxes 13-20 are mounted on a base plate 21 which runs the full width of the vehicle on which the system is to be mounted. A central fluorescent lamp 22 is positioned above the controller 11. Although not fully shown in Fig. 1, the light sources 12 and lamp 22 are enclosed by a plastic lens 23 secured to the base plate 21. Conveniently, the lens may be in three portions: a central portion 24 which ' covers the lamp 22 and end portions 25, 26 which cove the left and right hand arrays of the light boxes. The end portions may be (orange) coloured and each light source 12 may be provided with a plastic diffuser of different characteristics to produce different dioptric effects. Alternatively, each light source 12 may be enclosed by its own lens with or without a diffuser. The lens covering the lamp 22 may be adapted to carry the name of the service represented by the vehicle (e.g. POLICE). Turning now to Fig. 2, the circuit diagram of the main controller 10 has terminals 30, 31 for connection to the battery of the vehicle and terminals 32, 33, 34 and 35 for connection to the power supply and sequence controller 11. The main controller 10 has a fuse 36 to protect the system which is connected in the positive grid line 37. Negative grid line 38 connects the terminals 30 and 35. Beyond the fuse 36, the positive grid line 37 has two parallel branches 37a, 37b which lead to terminals 32, 33. Switch 39 in branch 37a energises the fluorescent lamp 22 and switch 40 in branch 37b controls the flashing of light sources 12. The sub-circuit within the dotted line I in Fig. 2 provides an intensity control signal to the terminal 34, the intensity of which is controllable by an operator's knob attached to the movable contact 41 on the potentiometer 42. The capacitor 43 protects the intensity control signal from transients and the zener diode 44 with its series -if . resistor 45 stabilizes the voltage across the resistor line of potentiometer 42. Conveniently, the main controller 10 au be located in the cabin of the vehicle so that the switches 39, 40 and intensity controller 46 are readily accessible to the driver. Multi-pin connectors 47 are used to connect the controller 10 to the battery and to the remainder of the flashing system. The electrical circuit of the power supply and sequence controller 11 shown in Fig. 3 has input terminals 32a, 33a:;- 34a and 35a which are connected to terminals 32, 33, 34 and 35 of the main control er 10. The power supply circuit consists of a pulse width modulator 48, switch driver 49 and a push-pull regulated switch mode DC-DC converter 50. The sequence controller or triggering means consists of a timer adjuster 51, a variable timer 52 and a sequence generator, counter 53. The negative grid line 38 is connected to the controller 11 through terminal 35a and grounded at point 54. The positive grid line 37a is connected through terminal 32a to output terminal 32b. Positive grid line 37b is connected to terminal 33a and has branches 55, 56. Positive grid line 55 is connected to regulator 57 to provide a 12 volt output which is applied to emitter of regulating transistor 58 to provide a 5 volt supply to the pulse width modulator 48 and to the timer adjuster 51. Grid line 55 also provides a dual 12 volt supply to the integrated circuit 69 of switch driver 49. Grid line 55 passes through filter 59 to the centre tap of winding 60 of the transformer 61. The output winding 62 of the transformer 61 is connected to rectifier bridge 63 and through the smoothing circuit 64 to provide a regulated high voltage output across terminal 33b and 33c. The output is sensed by feedback line 65 which is connected to the integrated circuit 66 of the pulse width modulator 48. The intensity control signal from terminal 34 of the main controller 10 passes through terminal 34a to the integrated circuit 66 of pulse width modulator 48 where it acts as a reference voltage against which the feedback voltage signal is compared. The pulse width modulator 48 has a clock generator which provides a pre-determined basic frequency which is used to provide a dual output signal in lines 67, 68 whenever the integrated circuit 66 of modulator 48 senses a difference between the reference and feedback voltages. The lines 67, 68 are connected to the integrated circuit 69 of the switch driver 49 which has outputs 70, 71 connected to field effect transistor 72, 73 through resistors 74, 75. The integrated circuit 69 of the switch driver 49 is arranged to provide the necessary current to turn on the gates of the field effect transistors 72, 73 alternately whenever the switch driver 49 receives an output signal from the modulator 48. Current limit adjustment 76 controls the time-on portion of the pulses from the modulator 48 from a minimum of 5% to a maximum of 45% of an on-off cycle. The field effect transistors 72, 73 are coupled in a push-pull manner to the winding 60 to provide the high output voltage to terminals 33b, 33c. The 5 volt regulated supply from the transistor 58 is also applied to the time adjuster circuit 51, variable timer 52 and sequence counter 53 all of which are arranged to provide trigger signals in a pre-determined sequence to the light sources 12 through terminals 77, 78, 79 and 80. Figure 4 shows the charging, firing and flashing circuits of the system for one of the light sources 12. There is a similar such circuit for each light source 12 within each of the boxes 13 to 20. The high output voltage from terminals 33b and 33c is connected to terminals 81 and 82. Positive grid line 83 runs from terminal 81 to terminal 84 and negative grid line 85 runs from terminal 82 to terminal 86. Charging diode 87 ensures that the storage capacitors 88 connected between lines 83 and 85 do hold their charge whenever the high output voltage is applied to terminals 81 and 82. The trigger signal from terminal 77 is applied to terminal 89 and through line 90 to the firing circuit 91 which includes a silicon controlled rectifier 92 and trigger transformer 93. -έ- The three terminal Xenon flash tube 94 is plugged into terminals 84 and 86 as well as terminal 95 connected to the trigger transformer 93. The firing circuit 91 is arranged so that when a trigger signal is applied thereto, the storage capacitors are effectively short-circuited through the Xenon flash tube 94 to produce a flash of light. The intensity of the flash is controlled by the voltage to which the capacitors are charged which is determined by the setting of the intensity potentiometer 42 in Fig. 2. In this instance, the boxes 16 and 17 are connected to terminal 77, boxes 15 and 18 to terminal 78, boxes 14 and 19 to terminal 79 and boxes 13 and 20 to terminal 80. The sequence generator counter is thus arranged to fire the flash tubes in boxes 16 and 17 simultaneously, then the tubes in boxes 15 and 13, then those in boxes 14 and 19 and finally those in boxes 13 and 20 to complete the sequence. The sequence is repeated for as long as the switch 40 on the main controller is closed. Different sequences and timing between flashes may be obtained by altering the connectors to the boxes and/or altering the timer components 51, 52 or sequence generator 53. The modification of the invention shown in Figs 5 to 7 has a number of components in common with the first embodiment and these carry the same reference numerals. The schematic arrangement in Fig. 5 has a sequence controller 100 and boxes 101 to 105 each of which has a Xenon flash tube 94 as the light source. The circuit of the sequence controller 100 is shown in Fig. 6 and includes a filter section 106, a voltage regulator 107, timer adjuster 51, variable timer 52 and counter 53. The terminals of the counter 53 are wired to provide flashing of the tubes in boxes 101 through to box 105 in sequence. In this embodiment, each box 101 to 105 has its own high voltage supply as is shown in Fig. 7. The vehicle battery supply is connected to terminals 108, 109, and through the filter and protective network 110 to the push-pull DC-DC converter 111. The high voltage output from the bridge (112) side of the transformer 113 is applied directly to the storage capacitor 114. The trigger signal is applied to the firing circuit 91 as before. O PI IPO ' The firing sequence could, of course, be arranged in an almost endless way. For example, the circuitary could be arranged to ensure that the light in box 102 flashes immediately it senses a flash by the light in box 101 and so on down the l ne to box 105. The dioptric effect generated by each flash may be controlled as to intensity and size. The storage capacitor and charging voltage controls the brightness of the flash and the type of the diffuser pattern controls the image size, shape and distribution. * Various modifications may be made in details of design, construction and/or mode of operation and thus many and varied configurations, both electrical and mechanical, will be embraced by the invention. For example, the capacitance means may be arranged to flash a group of light sources. Furthermore, the expression flashing sequence includes with its scope the flashing of a single light with set or variable gaps between flashes. OMPI ψ IPO

Claims: ■**■ ? - THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS: 1. A flashing light system comprising:- (i) a discharge light source, (ii) a first circuit for the light source having capacitance means and firing means for coupling the capacitance to the light source so that it discharges therethrough, (iii) a second circuit for providing a voltage to charge the capacitance means to a level which when the capacitance means is coupled to the light source will provide a high current short duration arc or flash, and, (iv) triggering means for a generating trigger signal which is supplied in a pre-determined sequence to the firing means so that the light source will flash in a pre¬ determined sequence and the second circuit will recharge the capacitance means so that the flashing sequence will be repeated. 2. A flashing light system according to claim 1 wherein there is a plural ty of light sources. 3. A flashing light system according to claim 2 wherein there is a first circuit for each light source. 4. A flashing light system according to claim 2 wherein there is a first circuit for a plurality of the light sources. 5. A flashing light system according to any one of the preceding claims wherein there is a common second circuit for all the light sources. 6. A flashing light system according to any one of the preceding claims wherein the second circuit includes means for comparing its output signal with a reference signal so as to activate the second circuit whenever there is a difference therebetween. _«5 - 7. A flashing light system according to claim 6 wherein the output signal and reference signal are compared within a pulse width modulator having a clock generator and which is adapted to provide a dual output signal whenever there is a difference between the output and reference signals. 8. A flashing light system according to claim 7 wherein the modulator outputs are applied to a dual output switch driver one output of which is connected to a first transistor and the second is connected to a second transistor and wherein the transistors form part of a push-pull DC-DC converter adapted to provide the charging voltage. 9. A flashing light system according to any one of the preceding claims wherein the second circuit is adjustable to provide a variable charging voltage so that the intensity of the flash may be varied. 10. A flashing light system according to any one of the preceding claims wherein the second circuit and triggering means are contained within a housing mounted on the base. 11. A flashing light system according to any one of the preceding claims wherein the light source is mounted on a housing which contains the first circuit. 12. A flashing light system according to any one of the claims 1 to 4 and 6 to 9 when appended to claim 1 either directly or directly wherein the light source is mounted on a housing which contains the first and the second circuit. 13. A flashing light system according to claim 1 and further including a pluarlity of light sources mounted on a base or bases in a spaced apart array and wherein there is provided lens means enclosing each light source. 14. A flashing light system substantially as hereinbefore described with reference to the accompanying drawings.

Inventors: CURRAN TIMOTHY RICHARD, CURRAN, TIMOTHY, RICHARD
Applicants: CURRAN TIMOTHY RICHARD, CURRAN, TIMOTHY, RICHARD
Application year: 1982
Main classification: H05B41
IPC codes: F21S8, H05B41