US3055303A - Fuses operating optically in the vicinity of the target - Google Patents

Description

Sept. 25, 1962 G. E. GIRAUDO 3,055,303

FUSES OPERATING OPTICALLY IN THE VICINITY OF THE TARGET Filed Jan. 15, 1957 N I jf\1o 7 ML 9 TTg 13 8 1,)

INVENTOR Georges Elie GIRAUDO AT ORNEYS Stats Unite 1 3,055,303 FUSES OPERATING OPTICALLY IN THE VICINITY OF THE TARGET Georges Elie Giraudo, 24 Rue Caumartin, Paris, France Filed Jan. 15, 1957, Ser. No. 634,238 Claims priority, application France Jan. 19, 1956 7 Claims. (Cl. 10270.2)

It is a well known fact that fuses may be operated in proximity of the target through optic means and that they include to this end a photocell adapted to release the operation of the fuse when the latter is subjected to predetermined luminous, infra-red, ultra-violet or the like rays.

In order that such fuses may operate by night, they may also include an arrangement for producing the desired radiation and this radiation reflected by the target is adapted to release the operation of the fuse.

In order that said fuse may operate without being dis turbed by any parasitic luminous rays such as the sunrays or the like which risk producing their untimely operation, it has already been proposed to modulate said infra-red, or ultra-violet luminous flux and to make use of a photocell detector adapted to operate only when it receives such a modulated luminous or the like flux which is returned onto it by the screening target in proximity with which the fuse is to explode, the modulation of said returned flux being obviously equal to the frequency of the flux transmitted by the fuse.

When executing such an arrangement in practice, it is possible to synchronize for a perfectly stable frequency the modulation of the transmitted waves and to synchronize similarly the receiving means, but this requires costly and bulky arrangements.

My invention has for its object to cut out these drawback and to obtain a suitable synchronization between the received waves and the transmitted waves, said synchronization being sufficient for it to be possible to obtain the desired result without perfect stability of the transmitted frequency being essential. This allows using for the modulation of the transmitted waves a simple mechanical arrangement actuated for instance by a mere blade propeller. Under such conditions, my invention consists in obtaining a constant selectivity for the reception to either side of the transmitting frequency, within a band of frequencies of a constant breadth, by resorting to a phase bridge.

Furthermore and preferably, I provide in conformity with my invention a preliminary selection of the received radiation by means of a band-pass filter the breadth of which is selected before operation so as to be sufliciently large to cover all modifications to which the transmitter may be subjected in practice.

I have illustrated diagrammatically and by way of example in the accompanying drawing a preferred embodiment of my invention. The single FIGURE of the drawing illustrates diagrammatically an arrangement according to my invention.

In said figure, 1 designates a mechanical modulator surrounding a source of light 2 and driven by a windwheel 3; said modulator may be constituted for instance by a simple rotary screen cutting off periodically the beam of light at the frequency provided by the windwheel. This modulator 1 carries one or more poles of magnetic material 4 adapted to move in front of a permanent magnet 5 provided with a winding 6. The voltage induced in said winding is app-lied to the feeding of a phase bridge including for instance as well known per se a transformer of which the secondary 7 has been illustrated at 7 while its primary 14 is fed by an amplifier filter 13 operating on a broad band of frequencies and following the photocell 1'2. Said band of frequencies is defined so as to provide for the passage of only those frequencies which lie within the extreme possible variations of modulation. The phase bridge includes furthermore two dry rectifiers 8 and 8', two resistances 9 and 9' and two condensers 1e and 10' connected across the outer terminals of the rectifiers between the two wires 11 and 11, which release in the conventional manner the operation of the fuse at 15. Untimely parasitic optic signals may be produced for instance if the target is illuminated by a non-stable light or else if the cell sees, for instance, the visible portion of the objective alternatingly as a dark or as a light surface. However, these parasitic optic signals correspond generally to a frequency which is very different from the modulation frequency and the phase bridge produces then no signal or if it did produce a signal, as may occur for certain ratios between the frequencies involved, it would be necessary for said parasitic signals to last enough time for the time constant constituted by the association of the resistances 9-9 and of the capacities 1tl-10 to be loaded, which is obviously hardly probable. On the other hand, the parasitic signal will have been relieved of all the frequencies incorporated with it, which are not included within the passing band of the amplifier.

Of course, it is possible to bring numerous modifications to the arrangement disclosed without unduly widening the scope of my invention as defined in the accompanying claims. In particular, the phase bridge may be executed in a manner different from that described and illustrated by way of a mere exemplification.

What I claim is:

1. In combination with a fuse adapted to operate in the proximity of the target, the provision of a light-controlled fuse operating system, comprising a source of light producing a luminous beam, means for producing a mechanical modulation of said luminous beam roughly at a predetermined frequency, light sensitive means adapted to receive the modulated beam reflected back by the target and to transform it into an electric current of the same frequency as that of the beam modulation, means for transforming the mechanical frequency of the beam-modulating means into an electric current of equal frequency, a phase bridge adapted to superpose said two currents of equal frequencies to produce a unidirectional current and fuse-operating means controlled by said unidirectional current from the phase bridge.

2. In combination with a fuse adapted to operate in the proximity of the target, the provision of a light-controlled fuse operating system, comprising a source of light producing a luminous beam, means for producing a mechanical modulation of said luminous beam roughly at a predetermined frequency, light sensitive means adapted to receive the modulated beam reflected back by the target and to transform it into an electric current of the same frequency as that of the beam modulation, means for transforming the mechanical frequency of the beammodulating means into a second electric current of equal frequency, a phase bridge including two rectifying bridge arms each of said bridge arms connected to the other at one end to form a connecting point, the connecting point between which is adapted to be fed in opposition by the first-mentioned current, the other ends of said bridge arms forming output ends, two condensers connected in series across the output ends of said arms, resistances connected in series across the output ends of said arms and a diagonal branch-circuit fed by the second current and connecting the connection point between the rectifying arms with the connecting points between the condensers and resistances and fuse operating means controlled by the current impulses produced by the superposition of the two currents in the phase bridge between the output ends of the rectifying bridge arms.

3. In combination with a fuse adapted to operate in the proximity of the target, the provision of a light-controlled fuse operating system, comprising a source of light producing a luminous beam, means for producing a mechanical modulation of said luminous beam roughly at a. predetermined frequency, light sensitive means adapted to receive the modulated beam reflected back by the target and to transform it into an electric current of the same frequency as that of the beam modulation, electromagnetic means for transforming the mechanical frequency of the beam modulating means into an electric current of equal frequency, a phase bridge adapted to superpose said two currents of equal frequencies to produce a unidirectional current and fuse operating means controlled by said unidirectional current from the phase bridge.

4. In combination with a fuse adapted to operate in the proximity of the target, the provision of a light-controlled fuse operating system, comprising a source of light producing a luminous beam, a wind-wheel for producing a mechanical modulation of said luminous beam roughly at a predetermined frequency, light sensitive means adapted to receive the modulated beam reflected back by the target and to transform it into an electric current of the same frequency as that of the beam modulation, means for transforming the mechanical frequency of the beam-modulating means into a second electric current of equal frequency, a phase bridge adapted to superpose said two currents of equal frequencies to produce a unidirectional current and fuse operating means controlled by said unidirectional current from the phase bridge.

5. In combination with a fuse adapted to operate in the proximity of the target, the provision of a light-controlled fuse operating system, comprising a source of light producing a luminous beam, means for producing a mechanical modulation of said luminous beam roughly at a predetermined frequency, a photo-cell adapted to receive the modulated beam reflected back by the target, an amplifier fed by said photocell, a transformer fed by the photocell and the secondary of which produces an electric current of the same frequency as that of the beam modulation, means for transforming the mechanical frequency of the beam modulating means into a second electric current of equal frequency, a phase bridge adapted to superpose said two currents of equal frequencies to produce a unidirectional current and fuse operating means controlled by said unidirectional current from the phase bridge.

6. In combination with a fuse adapted to operate in the proximity of the target, the provision of a light-controlled fuse operating system, comprising a source of light producing a luminous beam, means for producing a mechanical modulation of said luminous beam roughly at a predetermined frequency, a photo-cell adapted to receive the modulated beam reflected back by the target, an amplifier fed by said photo-cell and forming a band pass filter allowing the passage of the range of frequencies corresponding to the rough frequency of the modulation, a transformer fed by said photo-cell and the secondary of which produces an electric current of the same frequency as that of the beam modulation, means for transforming the mechanical frequency of the beam-modulating means into a second electric current of equal frequency, a phase bridge adapted to superpose said two currents of equal frequencies to produce a unidirectional current and fuse operating means controlled by said unidirectional current from the phase bridge.

7. In combination with a fuse adapted to operate in the proximity of the target, the provision of a light-controlled fuse operating system, comprising a source of light producing a luminous beam, a wind-wheel for producing a mechanical modulation of said luminous beam roughly at a predetermined frequency, a photo-cell adapted to receive the modulated beam reflected back by the target, an amplifier fed by said photo-cell, and forming a band pass filter allowing the passage of the range of frequencies corresponding to the rough frequency of modulation, a transformer fed by the photo-cell and the secondary of which produces an electric current of the same frequency as that of the beam modulation, electromagnetic means for transforming the mechanical frequency of the beam-modulating means into a second electric current of equal frequency, a phase bridge including two rectifying bridge arms each of said bridge arms connected to the other at one end to form a connecting point, the connecting point between which is adapted to be fed in opposition by the corresponding halves of the transformer secondary with the first-mentioned current, the two other ends of said bridge arms forming output ends, two condensers connected in series across the output ends of said arms, resistances connected in series across the output ends of said arms and a diagonal branch circuit fed by the second current and connecting the connection point between the rectifying arms with the connecting points between the condensers and resistances, and fuse operating means controlled by the current impulses produced by the superposition of the two currents in the phase bridge, between the output ends of the rectifying bridge arms.

References Cited in the file of this patent UNITED STATES PATENTS 2,137,598 Vos Nov. 22, 1938 2,234,329 Wolff Mar. 11, 1941 2,365,580 Murcek Dec. 19, 1944 2,490,899 Cohen Dec. 13, 1949 2,506,946 Walker May 9, 1950 2,524,807 Kallmann Oct. 10, 1950 2,632,040 Rabinow Mar. 17, 1953 FOREIGN PATENTS 159,501 Australia Oct. 27, 1954 159,839 Australia Nov. 17, 1954 268,889 Switzerland Sept. 16, 1950

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