US2910001A

US2910001A - Continuous charging circuit for stabilized timers

Info

Publication number: US2910001A
Application number: US290374A
Authority: US
Inventors: Herbert E Ruehlemann; Wolfgang A Menzel
Original assignee: Individual
Current assignee: Individual
Priority date: 1952-05-27
Filing date: 1952-05-27
Publication date: 1959-10-27
Anticipated expiration: 1976-10-27

Description

1959 .H. E. RUEHLEMANN ETIAL 2,910,001

CONTINUOUS CHARGING CIRCUIT FOR STABILIZED TIMERS Filed May 27, 1952 Wm m1. Tu W EM Z, .O VE N n m E A H MW EM .R

United States Paten CONTINUOUS CHARGING CIRCUIT FOR STABILIZED TllYlERS Herbert E. Ruehlemann and Wolfgan A. Menzel, Silver Spring, Md., assignors to the United States of America as represented by the Secretary of the Navy The invention described herein may be manufactured and used by or for the Government of the United States of America for'governmental purposes without the payment of any royalties thereon or therefor.

This invention relates to electric fuze circuits and more particularly to voltage stabilized time fuze circuits for use in bomb and rocket fuzes.

It is well known to use electrically energized fuzes in ordnance equipment to initiate the operation thereof. The components generally employed to energize and control the time of operation of such fuze mechanisms include condensers, resistors and condenser discharge control devices such as diodes arranged in various networks.

The problem of suitably charging the condensers for proper operation of the fuze mechanism of the specific piece of ordnance equipment before release varies with the equipment. Such charging may be accomplished either by means of a pulse charging circuit, as disclosed in the copending application, Serial No. 219,302, filed April 4, 1951, wherein stabilization is completed before the timing cycle starts, or a continuous charging circuit wherein the stabilization condenser is continuously being recharged through a long time constant circuit as disclosed in the instant application. The instant invention represents an improvement over the stabilization circuits there shown and disclosed.

Due to the electrical and mechanical variations in the diodes used in electrically actuated fuzes, as in the instant case, a special stabilization method is used in which the voltage on a condenser is adjusted to the exact value of the breakdown voltage of the diode used in the particular piece of ordnance equipment. This stabilization method is disclosed in the copending application previously referred to and for more complete information on this method reference thereto should be made.

Cold cathode diodes used in such stabilization circuits are normally connected during the charging cycle or directly thereafter to the stabilization device including the stabilizing condenser and 'when stabilization is accomplished, the diode is switched to the ignition circuit. Such switching action can be performed quite easily in a shell fuze where charging of the fuze circuit can be accomplished in the breech of a gun and the diode switching is a function of the firing of the shell. However, in bombs and rockets equipped with voltage stabilized time fuze circuits where the charge on the condensers has to be applied to the ignition circuit at the instant of dropping or firing the missile, this switching cannot be as readily accomplished, since when the bomb or rocket is in flight no forces are acting which can be used to perform such switching action. It would therefore be necessary to provide an additional delay mechanism to operate the diode switching. In order to avoid the use of clockwork mechanisms or pyrotechnic devices, which are undesirable and space consuming, it is proposed by means of the novel circuit arrangements herein disclosed to continuously charge the stabilizing condenser through a high resistance, shunted with a diode, additional to the conventional diode in the stabilizing circuit, for a certain time prior to the release of the bomb or rocket. The arrangement of the high resistance shunted by the diode immediately places a momentary overvoltage on the stabilizing condenser without the initial use of the diode in the stabilizing circuit. This arrangement permits the stabilizing process to be started at the instant the master power supply switch is turned on and immediately places the stabilizing circuit in operation and provides suflicient energy to the ignition circuit at the instant of release of the missile without having to first perform a diode switching operation involving the use of delay mechanisms, in the fuze. The diode switching in a missile having'voltage stabilized time fuze circuits can then be performed by the mechanism securing the bomb or rocket to the aircraft at the instant of release.

In order to overcome the problems indicated above in performing switching of the diode from the voltage stabilizing to the ignition circuit necessitated by the use of stabilized timer circuits in missiles such as bombs and rockets, it is a primary object of this invention to provide means other than mechanical or pyrotechnic devices to perform such diode switching.

It is a further object of this invention to provide in a voltage stabilized circuit means for applying a quick charge to the stabilizing condenser.

It is a further object of this invention to provide a voltage stabilized timer circuit wherein a continuous charge must be applied to the stabilizing condenser and may be applied to other condensers in the fuze circuit.

It is a further object of this invention to provide in an electric fuze circuit means whereby a slow charge may be applied to the voltage stabilizing condenser after an initial quick charge to initiate the voltage stabilizing process.

It isa further object of this invention to provide in a voltage stabilized time fuze circuit means whereby said circuit provides adequate energy to the ignition circuit of a bomb or rocket type missile at the instant of release.

It is a further object of this invention to provide in a voltage stabilized time fuze circuit of a bomb or rocket type missile means for switching a diode from the stabilizing circuit to the ignition circuit at the instant of release of the missile.

'It is a further object of this invention to provide in a voltage stabilized time fuze circuit means to reduce to a minimum the time for charging the stabilizing condenser and initiating the first step of the stabilizing process.

It is a further object of this invention to provide a voltage stabilized time fuze circuit for electric fuzes using continuous charge wherein a highrate of change of voltage setting may be applied to the fuze circuit.

Other objects. and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

On the drawing is shown one form of a voltage stabilized time fuze circuit diagram embodying the principles of the instant invention.

Referring to the drawing there is shown to the left of line A--A, a voltage divider 5 which is connected across the power supply of terminals 1, 2 and a switch S which may be the master power switch of an aircraft. To the right of the line A--A there is shown a continuous charging arrangement for a voltage stabilized time fuze circuit. Upon release of the missile, the fuze circuit is disconnected from the power supply at A-A. Switches 15 and 16 are actuated by the missile supporting device such as an aircraft bomb rack or rocket launching mechanism so that upon release the switches 15 and 16 are closed and connect the condensers 12, 22, 23 in series with the ignition circuit, including detonator 14. The switch S is an additional switch, installed on the missile, which may be used to disconnect the fuze circuit from the power supply.

The continuous charge voltage stabilized. fuze circuit illustrated in the form of the invention shown in the sole figure comprises the timing condenser 12 shunted; by its discharge resistance 13-, which condenser, when switches, 15, 16- are actuated by the release mechanism, is connected in series with diode 19 and with stabilizing condenser 22 and condenser 23. In conventional ignition circuits, the function performed by condensers 22 and 23 in the instant invention are generally performed by a single condenser. In the instant invention condenser 23 provides a reference voltage for setting the cycling rate of the voltage stabilization circuit; while the voltage on the stabilizing condenser 22- is exactly equal to the breakdown voltage of the diode 19. The charging circuit forthe stabilizing condenser 22 includes a high megohm resistor 18 shunted by a diode 17 The proper operation of the circuit requires a high value of resistance connected in series with stabilizing condenser 22 therebyrequiring a long time to charge this condenser to the'breakdown voltage of 'the diode 19; The diode 17 is therefore provided to short the resistance 18 when the master switch S1 is-closed to momentarily apply an overvoltage to the stabilizing condenser 22 thereby to start the stabilizing process which continues until release of the missile. At the instant of release with condensers 12 and 23 charged, the diode 19 is switched from the stabilizing circuit to the ignition circuit by the operation of switches 15 and 16 as a consequence of the release of the missile.

Due to the initial charge on condenser 12,. insufficient potential exists across diode 19 to render diode 19 conductive for discharging condenser 22 through detonator 14. After a predetermined time interval, as determined by the discharge rate of condenser 12 through resistor 13, the potential difference across diode 19 will become suflicient to render diode 19 conductive whereupon the charge on condenser 22 will be discharged through the diode and ignite the detonator.

In addition to the advantages previously indicated, by the use of continuous charging circuits for voltage stabilized time fuzes there is the additional advantage that the rate of change of voltage across condenser 12 can be higher since the rate of change influenced only by the time constant of the reference voltage condenser 23. ince thi n ens r is n rmally of. a small value, the resistance of the voltage divider has little influence on the charging time of the timing condenser, an Consequently upon the rate of change of voltage across condenser 12, which in turn has a, direct efiect on, the fuze time setting.

To obtain continuous charging of condenser 22. and stabilization steps at a frequency which will not influence the stabilizing and voltage breakdown of diode 19, a high value of resistance 18 is connected in seriesiwith, condenser 22. If such a large resistance were placed in. the. power supply, the value of insulation resistance, of the fuze circuit would have to be considerably higher to obtain the proper potential on condenser 22,. Proper, balance of circuit components would be diflicult under such conditions especially to meet military service requirements. It is therefore, necessary to include resistance 18 in the fuze directly. connected to the condenser 22. Additionally, in this position resistance 18 cannot be shortcdduring the charging cycle by the power supply to obtain a momentary overvoltage on condenser 22 to initiate the stabilizing process because switching action takes place in; the power supply and not in the fuze. However with. resistance 18 connected in series with condenser 22 the time required to charge condenser 22 high enough to start the stabilizing process is. several minutes which is too long for military purposes. To overcome this difficulty, a cold cathode diode 17 is connected in parallel with resistor 18.

At the instant of closing the master power switch S in the power supply, condenser 22 is charged through the diode 17 to a value equal to the applied voltage minus the extinguishing potential of the diode 17. It is therefore possible to provide a momentary voltage on condenser 22 which is higher than the breakdown voltage of h odc19 t us momen ari y starting a p lse. stabil tion action whichcontinues until the overvoltage on condenser 22 is drained down to the stabilization voltage as determinedv by the extinguishing potential of diode 19.. At this instant the pulse stabilization action is followed automatically byacontinuous stabilization process deter- "mined only; by the overvoltage and the resistance value of resistor 18.

The operation of the stabilizing process using continuous charging will now be described. Before charging the fuze or releasing the missile the master power switch S is moved to a position such that terminals 6a, 7a and 8a are in the circuit and in this position the three condensers 12, 22 and" 23' are shorted to ground and so discharged. For operation, the switch S1 is'moved from the short position to the chargeposition thereby placing contacts 6, 7' and 8 in circuit. At the instant of switching to the charge position the three condensers 1'2, 22- and 23 are connected to the voltage divider 5 of the power source. Condensers 12 and 23 are charged directly from the source but condenser 22 is indirectly connected. to the power-source by way of the diode 1'7 which breaks down at the instant of closing the master switch S1 thereby charging condenser 22 to a voltage equal to the potential in the power supply minus the potential drop across diode 1'7; Diode 17' then stops conducting thereby interrupting the initial charging path to condenser 22. At this, instant the condenser 22 ignites the diode I9d'ischargingr nt h c ndens r 21 un il. the voltag in condenser 21 is high enough to reduce the potential across diode 19 below the sustaining level off the diode 19' wh re p n h is harge. of cond nser. 22. is interrupted. The condens r .21 then partially'loses. its energy hro gh the resistor 20 and when, the voltage, in condenser 21 is lowered, enough the diode. 19 again ignites. This is. the so-called stabilization process as used in, the stabilization circuits disclosed in the copending application previously mentioned. By this stabilization operatio e volta across condenser will be lowered to-a valueiust below the. bre k own age of diode 19 so thatfurthcr abi: lization t p are. not. p ssi le- In h ircnithercin discl sed. the cond nser 22 is c n in o sly connected to the power upply bet re release of the. missile thro gh a high resistance element 18 which is in parallel with. diode 17. The condenser 22 is thereby continuously recharged through the resistor 18 at, a; very high time constant, After about 2,1 S6Q0fid101? more the voltage in condenser 22. is again increased to the breakdown voltage of diode. 19 whereupon diode 19commences to conduct and, partially discharges condenser 22 and a. new stabilization step. occurs. This cycling operation is repeated during the entire time the fuze isconnected to the power- Supply until the instant themissile is released and the stabilizing circuit disconne ted. fr m. he power supply. I

Qbviously many modifications and variations of the present invention are possible in the. light of the. above teachings. It is therefore to be understood that within th scope of the pp nded laims he. invention. may be. practiced. otherwise than as specifically described.-v

What is claimed. and desired to be secure by. Letters Patent of the United States is:

1. A charging circuit comprising a. voltage stabilizing device, a timing means connected to said device, means connected to said stabilizing device for developing a voltage pulse to initiate operation of said stabilizing device atthe instant of energization ofsaidstabilizing device and thereafter for developing aconti'nuous charge to said device, reference voltage means connected to said device, means for energizing said stabilizing device and said reference means, and means for disconnecting said energized stabilizing device from said energizing means.

' 2. A voltage stabilizing fuze circuit for a missile comprising a first RC timing circuit, a second RC circuit, a first condenser for maintaining a reference potential serially conected to a second condenser capable of being charged to a voltage in excess of said reference voltage, said second condenser serially connected to said second RC circuit through a first electron discharge device, an impedance network including a long time constant resistance and a second electron discharge device connected in parallel with said resistance, said impedance network being serially connected to said second condenser for applying a pulse voltage thereto for initiating a stabilizing process, said resistance thereafter applying a long time constant charge to said second condenser, an ignition circuit including an electro-responsive igniter, means for instantly connecting said stabilizing circuit to said ignition circuit through said first RC circuit. and said first electron discharge device, energizing means for said fuze circuit, and means for connecting and disconnecting said energizing means from said fuze circuit.

3. A voltage stabilizing circuit comprising an energizing source, an energy storage device chargeable. by said source, a discharge circuit connected across said energy storage device for successively discharging the charge on said energy storage device to a predetermined charge level, and circuit means interposed between said energizing source and said energystorage device for developing an initial energizing impulse for said energy storage device and for thereafter developing a continuous energizing charge for said energy storage device from said source.

.4. A voltage stabilizing circuitcomprising an energizing source, a first energy storage device connected to said energizing source adapted to be charged to a predetermined energy level therefrom, a second energy storage device chargeable by said energizing source, circuit means including a parallel coupled gas discharge device and impedance element interconnecting said source to said second storage device for applying an initial energizing impulse and for thereafter applying a continuous energizing charge to said second storage device, and a discharge circuit connected across said second storage device for successively discharging said second storage device to a predetermined energy level at a rate correlative to the charge on said first storage device.

5. A voltage stabilizing circuit comprising an energizing source, an energy storage device chargeable by said source, a discharge circuit connected. across said energy storage device for successively discharging the charge thereon to a predetermined charge level, said discharge circuit including a serially connected parallel R-C network and gas discharge device adapted to be successively rendered conductive and nonconductive, and circuit means interposed between said source and said storage device for providing an initial energizing impulse to said storage device and for thereafter providing a continuous energizing charge to said storage device from said source.

6. A voltage stabilizing circuit comprising an energization source, an energy storage device chargeable by said source, a discharge circuit connected across said energy storage device forsuccessively discharging the charge on said energy storage device to a predetermined charge level, and a parallel coupled resistance and gas discharge device interposed between said energizing source and said energy storage device for providing an initial energizing impulse to said energy storage device and for thereafter providing a continuous energizing charge to said energy storage device from said source. g

7. A time fuze circuit comprising an electroresponsive detonator, a first'energy storage device connected to said detonator being chargeable to a predetermined energy level and dischargeable to a predetermined level at a predetermined discharge rate, a second energy storage device chargeable to a predetermind energy level, a third energy storage device connected to said second storage device and chargeable to a predetermined energy level, an energizing source, circuit means for connecting said first, second and third energy storage devices to said source, said circuit being adapted to apply an initial energy impulse and thereafter a continuous energy charge to said second storage device, a discharge circuitconnected across said second storage device for discharging said second storage device to a predetermined energy level, and switching means for discretely connecting said second storage device to said first energy storage device through said discharge circuit for discharging said second storage device through the detonator at a time correlative to the discharge rate of said first storage device.

References Cited in the file of this patent UNITED STATES PATENTS Guanella Aug. 21, 1956