US3328634A

US3328634A - High-voltage igniter system for electronic flashlights

Info

Publication number: US3328634A
Application number: US448461A
Authority: US
Inventors: Theimer Siegfried
Original assignee: Individual
Current assignee: Individual
Priority date: 1965-04-15
Filing date: 1965-04-15
Publication date: 1967-06-27
Anticipated expiration: 1984-06-27

Description

June 27, 1967 s. THEIMERY 3,328,634

HIGH-VOLTAGE IGNITER SYSTEM FOR ELECTRONIC FLASHLIGHTS Filed April 15, 1965 PISA,

(0 U I I I FIG-.2

United States Patent 3,328,634 HIGH-VOLTAGE IGNITER SYSTEM FOR ELECTRONIC FLASHLIGHTS Siegfried Theimer, Hofstrasse 1, Offenbach am Main-Rumpenheim, Germany Filed Apr. 15, 1965, Ser. No. 448,461 4 Claims. (Cl. 315166) ABSTRACT OF THE DISCLOSURE This application discloses a high-voltage ignition system for electronic flashlights, such as xenon flashlights, which system is energized from an A-C current supply and wherein ignition is effected by an impulse circuit.

This invention has reference to high-voltage ignition systems for electronic flashlights, and more particularly to ignition systems for igniting the flashlights, or flash lamps, of photographic copying machines, of photographic reproduction systems and of photographic enlargers.

This invention is more particularly concerned with high-voltage ignition systems for xenon lamps which are particularly desirable for the above applications on account of their high efliciency, and on account of the spectral qualities of their light.

Flashlights of the above description may be used either for producing relatively short single flashes of predetermined duration, or for illuminating an object for a relatively long period of time, in which case the lights are re-ignited at each consecutive half-wave of the A-C circuit into which they are connected, and in such an instance they emit a light which appears to be constant.

This invention is applicable for either of the two above referred uses of xenon flashlights, or similar flashlights.

Flashlights may be classed into two categories, i.e. flashlights which are energized by discharging capacitors through the same, and flashlights which are energized from a supply of A-C current. Xenon flashlights, and other flashlights having a similar character, are energized from a supply of A-C current, and this invention is, therefore, concerned with flashlights which are energized from a supply of A-C current.

This latter kind of flashlights requires a high-voltage J impulse to initially ignite the flashlights. Once ignited, the flashlight will keep on operating at the frequency of the supply of A-C current to which it is connected.

The ignition of flashlights of the aforementioned description is effected by superimposing a high-voltage pulse upon the A-C operating voltage of the flashlight.

To this end the supply voltage for the flashlight may be stepped up by means of a high-voltage transformer, and the stepped-up voltage superimposed upon the normal operating voltage of the flashlight. The resulting voltage has, therefore, two components of equal frequency, but of different magnitude. In prior art arrangements of this kind the losses of igniting energy tend to be considerable, unless the high-voltage transformer is arranged close to the flashlight, or flash lamp, to be ignited. Another limitation of prior art arrangements of this kind consists in that the connection between the highvoltage transformer and the flashlight, or flash lamp, to be ignited calls for the use of a relatively expensive highvoltage cable.

"ice

It is, therefore, one object of this invention to provide improved high-voltage ignition systems for electronic flashlights which are not subject to the aforementioned limitations and/ or drawbacks.

Another prior art ignition sytem for flashlights comprises a capacitor and an electromagnetically operated switching device for charging and discharging the capacitor in the rhythm of the frequency of an A-C supply system. In a modification of this prior art ignition system the electromagnetically operated switching device controls also an interrupter arranged in the energizing circuit of the electromagnetically operated switching device and interrupting the energizing circuit of the electromagnetic switching device in the rhythm of charging and discharging the aforementioned capacitor.

The aforementioned prior art systems are subject to the limitation and/or drawback that the energy which is available for the purpose of igniting a flashlight, or flash lamp, is solely determined by the capacitance of the capacitor. Its capacitance cannot be increased at will because there is a time limit Within each half cycle available for charging and discharging the capacitor. This limitation is particularly serious when it is desired to use ignition pulses having a higher frequency than the A-C supply normally operating the flashlight, or flash lamp.

It is, therefore, another object of this invention to provide high-voltage ignition systems of the aforementioned description wherein the energy available for ignition purposes is not limited by the size of a capacitor and wherein the ignition voltage is, or may be, a voltage having a relatively high frequency, or a frequency in excess of the frequency of the current supply normally operating the flashlight, or flash lamp.

These and other objects of the invention and advantages thereof will be better understood from the following detailed description and the accompanying drawing showing diagrammatically a preferred embodiment of the inventio-n.

FIG. 1 is a circuit diagram of a flashlight embodying the present invention and FIG. 2 is a diagram of a transformer used for energizing the circuitry of FIG. 1.

Referring now to the drawing, reference characters L and L have been applied to indicate a pair of xenon lamps which are serially connected into an electric circuit. The terminals A and A are connected to a supply of A-C current having a circuit voltage of 450 volt and a frequency of 50 c.p.s. A switch S which may be manually operated, if desired, is provided to close the circuit of flashlights, or flash lamps, L L The voltage-responsive relay R is shunted across flash lamps L L The relay R is responsive to the supply voltage of 450 volt, and closes contact r whenever energized. When flashlights, or flash lamps, L L are ignited, and their high initial resistance broken down, the voltage previously prevailing across relay R breaks down, and the latter becomes inoperative, resulting in opening of contact 1'. Contact r is arranged in the primary or low-voltage circuit of an impulse transformer T including the primary low-voltage winding I and the secondary high-voltage Winding II. One end of the latter is conductively connected to a center tap arranged between flashlamps L and L The primary circuit of transformer T may also include the manually operable closing switch ZS. The number of turns of winding II of transformer T,. by far exceeds the number of turns of winding I. Therefore energizing or dc-energizing of winding I results in generation of a very high voltage in winding II. Transformer T is preferablybut not necessarilyan autotransformer, as shown in the drawing. Winding I is energized by terminals connected to a source of A-C having a circuit voltage of 220 volt and a frequency of 50 c.p.s. Reference character U has been applied to designate a current-responsive relay operating an interrupter 11 including a pair of cooperating separable contacts. The energizing winding of relay U and the contacts of interrupter u are connected in series with the primary low-voltage winding I of transformer T,. The capacitor C is shunted across the primary transformer Winding I and the interrupter u.

The energizing circuit of the primary winding I of transformer T is interrupted whenever the contacts of interrupter u part from each other. Separation of the contacts of interrupter u is effected by the current-responsive relay U. Separation of the contacts of interrupter it causes the generation of a high-voltage pulse in winding II of impulse transformer T As a result, either of the two flashlamps L and L is ignited, the particular lamp to be ignited depending upon the direction of the high-voltage pulse. Separation of the contacts of interrupter it results also in the de-energization of relay U. Capacitor C is being charged by the 220 volt current supply during the time interval during which the contacts of interrupter u are separated. Contacts of interrupter u are moved again to their far latter moves closing position, resulting in a discharge of capacitor C through winding I of transformer T This, in turn, causes re-energization of relay U and reopening of the contacts of interrupter u. The high-voltage pulse resulting from the discharge of capacitor C ignites the second flashlight which had not previously been ignited. Flashlights, or flashlamps, L L are supplied with highvolta-ge pulses until both are ignited. Upon being ignited the voltage across both flashlights, or flashlamps, L L breaks down. This causes de-energization of relay R, opening of its contact 1-, thus rendering the ignition system inoperative. FIG. 2 shows a transformer having a low voltage winding connected to a 50 c.p.s. current supply and a tapped high voltage winding. Reference characters A A, have been applied in FIG. 1 to indicate the terminals of the impulsing circuit. Terminal A of the main supply and terminal A of its impulsing circuit supply are identical, as clearly apparent from a comparison of FIGS. 1 and 2. Terminals A and A of FIG. 1 are connected to the taps of the secondary winding of the transformer bearing the same reference characters. There is an AC voltage of 450 volt between terminals A and A and an A-C voltage of 220 volt between the terminals A and A Relay U is preferably designed in such a way that it operates at a higher frequency than the frequency of the supply of current to which it is connected, e.g. a higher frequency than 50 c.p.s. In other words, the armature of the relay performs several oscillations during each half cycle of its energizing current. Therefore the frequency at which interrupter u operates is a multiple of the frequency of the current energizing relay U.

While there has been described what is at present considered to be the preferred embodiment of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made without departing from the invention, and it is, therefore, aimed in the appended claims to cover all such changes and modifications as fall within the true spirit of the invention.

What is claimed is:

1. A high-voltage ignition system for electronic flashlights comprising in combination:

(a) a flashlight having a pair of electrodes;

(b) a first pair of terminals for connecting said flashlight to a supply of current;

(0) means for superimposing a voltage upon the voltage prevailing between said first pair of terminals to obtain an aggregate voltage sufficient to ignite said flashlight, said voltage superimposing means including an impulse transformer having a primary lowvoltage winding and a secondary high-voltage winding conductively connected to one of said pair of electrodes of said flashlight to transmit high-voltage firing impulses to said one of said pair of electrodes;

(d) a second pair of terminals for connecting said primary low-voltage winding of said impulse transformer to a supply of current;

(e) a current-responsive relay mechanism and an interrupter having a pair of separable contacts periodically operated by said relay mechanism;

(f) conductor means for serially connecting said second pair of terminals, said relay mechanism, said interrupter and said primary low-voltage winding of said impulse transformer; and

(g) a capacitor shunted across said primary winding of said impulse transformer and across said pair of separable contacts of said interrupter.

2. A high-voltage ignition system as specified in claim 1 including a voltage responsive relay shunted across said pair of electrodes of said flashlight operative upon breakdown of the voltage drop across said pair of electrodes of said flashlight resulting from firing of said flashlight, and a switch for controlling energization of said primary lowvoltage winding of said impulse transformer under the control of said voltage responsive relay for de-energizing said low-voltage winding upon breakdown of said voltage drop across said pair of electrodes.

3. A high-voltage ignition system for electronic flashlights comprising in combination:

(a) a flashlight having a pair of electrodes;

(b) a first supply of current connected to said pair of electrodes of said flashlight;

(c) means for superimposing a voltage upon the voltage of said first supply of current to obtain an aggregate voltage suflicient to ignite said flashlight, said voltage superimposing means including an impulse transformer having a primary low-voltage winding and a secondary high-voltage winding connected to one of said pair of electrodes of said flashlight to transmit high-voltage firing impulses to said one of said pair of electrodes;

(d a second supply of current for energizing said impulse transformer, said second supply of current having a predetermined frequency;

(e) a current-responsive relay mechanism and an interrupter having a pair of separable contacts both serially connected with said primary low-voltage winding of said impulse transformer into the circuit of said second supply of current, said relay mechanism operating said interrupter at a higher frequency than said predetermined frequency; and

(f) a capacitor shunted across said primary winding of said impulse transformer and across said pair of separable contacts of said interrupter.

4. A high-voltage ignition system for electronic flashlights comprising in combination:

(a) a pair of flashlights each having a pair of electrodes;

(b) conductor means for serially connecting said pair of flashlights into an electric circuit, said conductor means including a center tap between said pair of flashlights;

(c) means for superimposing a voltage upon the voltage of said electric circuit to obtain an aggregate voltage suflicient to ignite each of said pair of flashlights, said voltage superimposing means including an impulse transformer having a primary low-voltage winding and a secondary high-voltage winding conductively connected to said center tap to transmit high-voltage fin'ng impulses to said pair of flashlights;

( d) a current-responsive relay mechanism and an interrupter having a pair of separable contacts periodically operated by said relay mechanism;

(e) conductor means for serially connecting said primary low-voltage Winding of said impulse transformer, said relay mechanism and said pair of contacts of said interrupter into an electric circuit; and

(f) a capacitor shunted across said primary low-v-oltage winding of said impulse transformer and across said pair of separable contacts of said interrupter.

References Cited UNITED STATES PATENTS 12/1945 Clark 315-241 X 12/1954 Lautenberger 315-189 X 11/1964 Mutschler 315-17l X 3/ 1965 Michalski 315241

Claims

1. A HIGH-VOLTAGE IGNITION SYSTEM FOR ELECTRONIC FLASHLIGHTS COMPRISING IN COMBINATION: (A) A FLASHLIGHT HAVING A PAIR OF ELECTRODES; (B) A FIRST PAIR OF TERMINALS FOR CONNECTING SAID FLASHLIGHT TO A SUPPLY OF CURRENT; (C) MEANS FOR SUPERIMPOSING A VOLTAGE UPON THE VOLTAGE PREVAILING BETWEEN SAID FIRST PAIR OF TERMINALS TO OBTAIN AN AGGREGATE VOLTAGE SUFFICIENT TO IGNITE SAID FLASHLIGHT, SAID VOLTAGE SUPERIMPOSING MEANS INCLUDING AN IMPULSE TRANSFORMER HAVING A PRIMARY LOWVOLTAGE WINDING AND A SECONDARY HIGH-VOLTAGE WINDING CONDUCTIVELY CONNECTED TO ONE OF SAID PAIR OF ELECTRODES OF SAID FLASHLIGHT TO TRANSMIT HIGH-VOLTAGE FIRING IMPULSES TO SAID ONE OF SAID PAIR OF ELECTRODES; (D) A SECOND PAIR OF TERMINALS FOR CONNECTING SAID PRIMARY LOW-VOLTAGE WINDING OF SAID IMPULSE TRANSFORMER TO A SUPPLY OF CURRENT; (E) A CURRENT-RESPONSIVE RELAY MECHANISM AND AN INTERRUPTER HAVING A PAIR OF SEPARABLE CONTACTS PERIODICALLY OPERATED BY SAID RELAY MECHANISM; (F) CONDUCTOR MEANS FOR SERIALLY CONNECTING SAID SECOND PAIR OF TERMINALS, SAID RELAY MECHANISM, SAID INTERRUPTER AND SAID PRIMARY LOW-VOLTAGE WINDING OF SAID IMPULSE TRANSFORMER; AND (G) A CAPACITOR SHUNTED ACROSS SAID PRIMARY WINDING OF SAID IMPULSE TRANSFORMER AND ACROSS SAID PAIR OF SEPARABLE CONTACTS OF SAID INTERRUPTER.