US2817963A

US2817963A - Photographic flash equipment of the battery-condenser type

Info

Publication number: US2817963A
Application number: US398561A
Authority: US
Inventors: Scholkemeier Friedrich-Wilhelm
Original assignee: Rollei Werke Franke und Heidecke GmbH and Co KG
Current assignee: Rollei Werke Franke und Heidecke GmbH and Co KG
Priority date: 1952-12-17
Filing date: 1953-12-16
Publication date: 1957-12-31
Anticipated expiration: 1974-12-31

Description

Dec. 3l, 1957 2,817,963

FRIEDRICH-WILHELM SCHOLKEMElER PHOTOGRAPHIC FLASH EQUIPMENT-0F THE BATTERY-CONDENSER TYPE Filed DSC. 16, 1953 United States Patent PHOTOGRAPHIC FLASH EQUIPMENT OF THE BATTERY-CONDENSER TYPE Friedrich-Wilhelm Scholkemeier, Braunschweig, Germany, assignor to Franke & Heidecke, Fabrik Photographischer Przisions-Apparate, Braunscliweig, Germany, a firm Application December 16, 1953, Serial No. 398,561

Claims priority, application Germany December 17, 1952 11 Claims. (Cl. 67-31) This invention relates to photographic ash equipment of the kind often referred to as the battery-condenser type, in which a small battery is used to charge an electric condenser or capacitor, and in which the electrical energy stored in the condenser or capacitor is used to ignite or re the flash bulb. Apparatus of this general type is known, but such apparatus in the previously known forms is not entirely satisfactory, particularly when it is desired to connect one or more additional or supplementary flash bulb sockets to the socket of the main or primary flash bulb.

Among the diiculties likely to arise upon the use of additional or supplementary bulbs in apparatus as heretofore used, may be mentioned the following: If the supplementary bulb is connected in parallel with the main bulb, there is no longer any complete assurance of firing, inasmuch as the discharge current of the condenser is split up among two or more parallel paths. Thus firing failures are likely to result, particularly if different types of flash bulbs are used in different sockets. If one or more additional flash bulbs are connected in parallel to the series connection of the main bulb and its condenser, the additional bulbs form a closed circuit with the condenser and the main ash bulb, so that if the additional bulbs are inserted in their sockets after the main bulb has already been inserted in its socket, all of the bulbs are likely to be fired at the moment of the last connection. `On the other hand, if the additional bulbs, with this arrangement, are inserted in their sockets lirst, and the main bulb is inserted last, then no charging of the condenser will take place, as the charging current will be shunted through the additional bulbs, so that a failure of firing of all the bulbs will result. Or again, if each additional bulb is provided with its own condenser in series with the bulb, and if all of the additional bulbs and their series condensers are connected in parallel to the battery, a failure to lire is also possible. Upon the insertion, at the latest, of the third bulb in its socket, a firing of at least this third bulb is likely to occur since the condensers of the rst two bulbs have meanwhile become charged, and will discharge n a pulse-like manner into the newly connected condenser upon insertion of the third bulb.

An object of the present invention, therefore is the provision of generally improved and more satisfactory photographic flashlight apparatus of the batterycondenser type, so designed and constructed as to permit the convenient and reliable use of any desired number (within reason) of additional or supplementary ash bulbs, in combination with the main or primary flash bulb.

Another object is the provision of such apparatus or equipment so designed and constructed that premature firing or failure to re will not occur, regardless of the order in which the various bulbs are inserted in their sockets or holders.

A further object is the provision of simple photoflash equipment suitable for use with electrolytic condensers, including a switch to interrupt the residual current which ,tends to ow through condensers of the electrolytic type.

A still further object is the provision of a construction in which the switch for interrupting the residual current is built into one of the bulb sockets so as to be automatically operated by insertion or removal of the flash bulb.

These and other desirable objects may be attained in the manner disclosed as an illustrative embodiment of the invention in the following description and in the accompanying drawings forming a part hereof, in which:

Fig. l :s a diagrammatic or schematic view of a construction in accordance with a preferred embodiment of the invention; and

Fig. 2 is a schematic drawing of part of the construction shown in Fig. l, illustrating additional details.

The same reference numerals throughout the several views indicate the same parts.

Referring first to Fig. 1 of the drawings, there is here shown diagrammatically llash equipment in the form of a main flash unit or flash gun comprising the parts within the dotted rectangle 41, with provision for adding supplementary or additional flash units or flash guns of any desired number, as shown by the parts outside of the rectangle 41. The main unit or primary unit includes, within a suitable casing or frame, a battery 1 (for instance, a battery providing 22.5 volts) connected in circuit with a protective resistance 2 (for instance, a resistance of 2500 ohms), the circuit further extending through a switch 12 to a condenser or capacitor 3 (having a capacitance, for instance, of microfarads), the circuit from the condenser 3 back to the battery 1 having in series a resistance 15 of a value, for example, of 2500 ohms. Arranged in parallel with the resistance 15 is the socket for the main or primary flash bulb 4.

A switch 5 is connected across the main circuit above mentioned, by means of switch wires 30 and 3,1, the former leading from the switch to the main circuit at a point between the resistance 2 and the switch 12, and the other wire 31 leading from the other side of the switch 5 t0 the main circuit at a point between the battery 1 and the socket of the main ash lamp 4. This switch 5 is the main control switch or operating switch for tiring the flash bulb or bulbs. It is here shown diagrammatically as a simple single pole switch mounted on the main unit 41, although in actual practice this main ring switch 5 is usually the synchronizer switch built into the photographic shutter on the camera with which the flash equipment is used, or is a switch forming part of a separate synchronizer attached to and operating with the shutter of such camera, as well understood in the art.

With this arrangement, if the switch 12 is closed, the `condenser or capacitor 3 becomes charged from the battery 1, through the

resistances

2 and 15, if no bulb is present in the socket of the bulb 4. However, if a bulb is present, the condenser becomes charged through the bulb, which is in parallel with the resistance 15 and which, when present, serves to short circuit the resistance 15, since the resistance 15 has a value considerably higher than the internal resistance of the bulb 4. Preferably the switch 12 is closed automatically by insertion of the bulb 4 into its socket, and is opened automatically by removal or ejection of the bulb from its socket, in the manner `disclosed below.

With the condenser 3 fully charged, the closing of the switch 5 will allow the charge in the condenser 3 to ow through the bulb 4, thus tiring the bulb in the desired manner. As soon as the bulb is tired and the switch 5 is again opened, the condenser 3 is immediately recharged if the switch 12 remains closed. But upon opening the switch 12, by ejection or removal of the bulb from its socket, the circuit from the battery to the condenser is broken and thus there is no wastage of current from the battery while there is no lamp in the socket, which wastage would otherwise occur if the switch 12 3 were not present, on account of the residual current characteristics of the condenser 3 if this condenser is of the electrolytic type. v

For enabling connectionl of anydesirednurnber of vadditional or supplementary f flash units,y the Vterminals k8 and- 9 are provided, ot` any suitable form s uch as male yand female plug terminals ordbavyonetjoint terminals. .The terminal Svis connected to the switch -sideof the condenser 3 while the'lterminal is connected to the batteryside ofthe bulb- 4 and iresistance 15. Each supplementary unit comprises a dash bulb socket and acon- .denser s in iseries with each, ,o ther, yto ,bel connected across theterrninals 8 a ndr 9,` yand a resistancein parallel around the bulb socket, the resistance being of greaterresistance .than .that of the-.flash bulb,vv justjas in the case of the resistance w hi ch isffobgreater resistance-. than the bulb 4. .Thus, forexample,-.the lampf6 and, condenser 10 of one supplementary unitware. connected across the terminals .8f and 9, Vin serieswith leach other, ,andj with a resistance 16 in ,parallel around the 4 socket .fofz `thev AIlamp f 6. If a; secondsupplementaryunit is to be `used,.:the `socket of its lamp-7 is connected yin series with the con- ,de'riser 11, likewise across the terminals and 9 and in` parallellwith-.the .lamp 6 and condenser10, anda supplernfentary ,resistance-.17 is .connected infparallel aroundthe larnp- 7, a'sshownin Fig. l. .Any desired num- .ber" (within, reason) of 4additional supplementarylunits may be added in the same way.

rIf the supplementary unit or ur 1i ts are cor 1nected across thefterminals 'and'9 of-,the mainunitoinash gun 41, vin ,the rnannershowm it isseen that all of thecondensers 3, 10,.`and lliwill bechargedbyk the battery 1, as soon as tl1e .s.wit`ch`1 2 isf-closed v(or` as .soon as the, supplementary Aunits are connected Ito, the main unit,-;if the switch 412 is already' closed) regardless of whether` there are-bulbs in the` various. sockets and. regardless of `the fc'rderffin which,lmlbsfbr,freshA bulbs are inserted .in the varioiisjsockts,'fo ineach` case thecondensers 3,10, and `11 are" charged through'fftheir Yrespective rsistances 15, 1'6, and l17,.itl rnol bulbs `orf'if burned out bulbs are present. Thus'the order or sequencein which bulbs areinserted isimmaterial,` due to theprovision of the rsistances, andthe electric equilibrium is'not disturbed by the insertion of new bulbs.

As already mentioned, `the switch 12 is preferably operated automatically fbyinsertion of thebulb 4 in its "socket, or removal` o`f the bulb'frbm"the socket. Thisfis shown dia'grammatically vin Fig. r1,' and 'in somewhat 'g'rea'terstructural detail in Fig. 2'. VThe-baise",'contact "'14 of the lbulb Vsocketfisfformed on '-a Aleaf sprin'glwhich also carries the insulating.; plate 24 on which one'side 12 of the switch is'c'arriedf The axial insertion'of the fshankr of the bulb 4 into its',soc`kt"21`causes -the cenftral vcontact." 23,0f` the Qbulb 'to press 4on Vthe centralfcontact member 22 Aof the4 socket (the member 22 being 'fo'rrned `on the'spring 14 and thereby/lle'xes` the .spring "14, carrying the insulating plate`24"`andthe switchpart 12 in a downwardV yc`li'rectic`1n` when viewed asin Fig. 2, until, the switch Apart 12 comes Ainto contact witlia spring 'arm 25 constituting theother v'side of this switch. `Thus ythe switch is closed uponinsertion of the bulb 4, and tsprings fopen again when the bulb 4 is removed or ejected. .The bulb, as customary, is held in the socket by 'means of a bayonet slot in the side walls of 4the socket engaging radial pinsor projections on the shank ',ofthe bulb, althougha screw type of bulb shank and socketcould be used if desired. The contact -mernber 25 constituting the other side of the switch 12 is inthe form of a wiperv arm constantly `pressing vagainst'and 'in conductive relation to the,co 'n ffductingldisk'vZ torinedcn. onel sideQofthe cable drum "or lcord d'rurri` 2 7 which is rotatively vsupported on the "housing 28y ofthe iiash gun or 'ashunit Cin (the drum 27 "isA reeled 'the two wire electric cable .orjcord 29 containi'ng the wires,30, andf31 whichleadasiabove inengermana tioned, to the main ring switch 5 which is located on the associated photographic camera or its shutter. The wire 30 is electrically connected to the disk 26 so that it is conductively connected to the spring 25, while the other wire 31 of the cable 29sis electrically connected to the metal disk 32 which makes connection with the lamp housing 28, thus being grounded on the housing of the flash unit, which constitutes one side of the electric circuit. A hand wheel or knob 43, mounted on the shaft o-f the reel 27 and laccessible externally of the Ycasing 28, serves for manually turningthe reel27` to wind up the core 29 when the ash gun or unit is disconnected from the camera.

In the preferred arrangement, as above set forth, there isa

protective resistance

15, 16, 17 connected in parallel around each of the ash bulbs. 4, 6, and 7, respectively. This is preferred because with this arrangement it is immaterial in which order or sequencethe various bulbs vare renewed, after tiring. But if the operator takes 'care to insert the *fresh bulbs in the `supplementary flash [guns first, and then to insert a fresh bulb 4 in the main ilash gun after the supplementary gun bulbs have been replenished, the supplementary units can be used safely in connection with an old fstyle `flash unit which does 4not have Athe protectivefresistance 15. With such an arrangement, the

condensers

10 and 11 of the supplementary units will be charged before ythe bulb 4 of the main unit is renewed, and then when the main bulb is renewed it will not be prematurelyred. Hence the supplementary units of the present invention have the double advantage that they, can lbe succe ssfully employed also with a main unit or a'sh vgun ofthe standard type` in accordance 'with they prior art, but 'the vgreatest advantages ofl the preseutfinventionare achieved, of course, when the supplementaryunits in accordance 'with the present invention are employed Iwith a` main unit which v is 'alsoof the "new Vkind/in accordance with the present invention.

Since it has been j-mentionedjabo've, that a red ash bulb is replaced by a fresh bulb, it will be apparent to those skilled in the art that the Hash bulbs in question are of the ordinary` photoilash type, having a glass envelope filled withshredded foil or wire made of magnesium or other combustible material. Thus these photoilash bulbs may bereferred toas bulbs of the combustible and'consumable type, `usable only once, as distinguished from the gas filled multiple Hash type of bulb which may .b e vflashed repeatedly vand is not limited to a single Hash operation. 'The problems to be solved Vin dealing with bulbs of the consumable type are different from` thoseencountered in gasflled bulbs of the repetitive type, yfor the latter 'will conduct no'current until a certain critical voltage is reached, whereas the ordinary photoflash bulbs ofthe consumable type have a relatively low internal resistance and will conduct some current at any voltage. It isthis fact which accounts for certain types of misring 'or malfunctioning of photoflash apparatus when using consumable bulbs, and which accounts for the fact that various electricircuit'arrangements which are suitable for use with gaslled repetitive flash bulbs are not suitable for use with photoflashl bulbs of the ordinary combustible or Yconsumable type.

It is seen from the foregoing disclosure that the above mentioned objects of the inventionare well fulfilled. It

`its feed ycontacts-21, 22 beforethe members 1 4, 24 are displaced farrenough toY close the Thevalues of the condensers `or ca; acitors inrthesupresistors therein, are preferably substantially the same as those in the main unit. Thus thecapacitors 3, 10, and 11 preferably all have a capacity of about 100 microfarads, or in the order of magnitude of about 100 to 200 mf. The

resistors

15, 16, and 17 preferably all have resistances of about 2500 ohms, these resistances being substantially higher than the internal resistances of the

photoash bulbs

4, 6, and 7.

What is claimed is:

l. A supplementary photographic ash unit for electrical connection in parallel with a photoash bulb and condenser of a main Hash unit of the battery-condenser type, said supplementary unit comprising a supplementary socket for holding a supplementary photoash bulb, a supplementary condenser electrically connected in series with said socket, a protective resistor electrically connected in parallel with said socket and in series with said supplementary condenser, said resistor having a resistance substantially larger than that of a photoash bulb intended to be used in said supplementary socket, and electrical leads for connecting one side of said supplementary condenser and the remote sides of said supplementary socket and resistor to a main ash unit.

2. A photographic flash unit comprising an electric circuit including a battery, a condenser, and a photoflash bulb socket all in series with each other, a protective resistor arranged in said circuit in parallel with said bulb socket and in series with said battery and condenser, the resistance of said resistor being greater than the resistance of the photoflash bulb used in said socket, and an electric switch operatively interposed in said `circuit between said battery and said condenser.

3. A photographic flash unit comprising an electric circuit including a battery, a condenser, and a photoash bulb socket all in series with each other, a photoash bulb of the consumable non-repetitive type operatively connected in said socket, a protective resistor arranged in said circuit in parallel with said bulb socket and in series with said battery and condenser, the resistance of said resistor being greater than the resistance of the photoash bulb used in said socket, a bulb firing circuit operatively connecting the respectively remote sides of said condenser and said socket to each other independently of said battery, and a tiring switch in said tiring circuit to open and close the same.

4. A construction as defined in claim 3, in which said firing switch is mounted on a photographic camera and in which said phototlash bulb is so placed as to illuminate the scene to be photographed by the camera, and in which said firing circuit includes a flexible cord extending from said flash unit to the camera on which said switch is mounted, said unit further including a built-in reel on which said cord may be wound when not in use, and an externally accessible handle for turning said reel to wind said cord thereon.

5. A photographic ash unit comprising an electric circuit including a battery, a condenser, and a photoflash bulb socket all in series with each other, a protective resistor arranged in said circuit in parallel with said bulb socket and in series with said battery and condenser, the resistance of said resistor being greater than the resistance of the photoash bulb used in said socket, and a supplementary flash unit for electrical connection to said first mentioned unit for tiring simultaneously therewith, said supplementary unit including a supplementary socket for holding a supplementary photoash bulb, a supplementary condenser electrically connected in series with said supplementary socket, a supplementary resistor electrically connected in parallel with said supplementary socket and in series with said supplementary condenser, said supplementary resistor having a resistance greater than the resistance of the photoash bulb used in said supplementary socket, and circuit connections for electrically connecting the respectively remote sides of said supplementary condenser and supplementary socket re- 6 spectively to the corresponding sides f said condenser and socket of said first mentioned unit.

6. A construction as defined in claim 2, further including means for automatically closing said switch upon insertion of a photoflash bulb into said socket and opening said switch upon removal of a bulb from said socket.

7. A construction as defined in claim 6, in which said bulb socket includes two feed contact members for making electrical contact with a photoflash bulb inserted into said socket, and in which said means closes said switch only after a bulb, during insertion in said socket, has made contact with both of said feed contact members.

8. A supplementary photographic ilash unit for electrical connection in parallel with a main photoash bulby of the combustible and consumable type and with a con-- denser of a main flash unit of the battery-condenser type, said supplementary unit comprising a supplementary bulbA socket, a supplementary photoash bulb of the combustible and consumable type electrically connected in said socket, a supplementary condenser electrically connected in series with said socket and with said supplementary' in series with said supplementary condenser, said resistor having a resistance substantially larger than that of said supplementary bulb, and electrical leads for connecting the side of said supplementary condenser which is remote from said supplementary bulb and the sides of said supplementary socket and resistor which are remote from said supplementary condenser to a main flash unit.

9. The combination with a main photoas'h unit comprising a source of current, a rst resistor and a main photoliash bulb electrically connected in series with each other and with said source, a second resistor electrically connected in parallel with said photoash bulb and in series with said rst resistor and said source, and a main condenser electrically connected in series with said source, rst resistor, and second resistor, of a supplementary photoash unit comprising a supplementary condenser and a supplementary photoflash bulb electrically connected in series with each other and in parallel with said main condenser and main photoash bulb, and a supplementary resistor electrically connected in parallel with said supplementary bulb in bypass relation thereto, said supplementary photoflash unit having no yseparate source of current of its own.

l0. The combination with a main photoash unit comprising a source of current, a rst resistor and a main photoash bulb electrically connected in series with each other and with said source, a second resistor electrically `connected in parallel with said p'hotoash bulb and in series with said iirst resistor and said source, and a main condenser electrically connected in series with said source iirst resistor, and second resistor, of a supplementary phototlash unit comprising a supplementary condenser and a rsupplementary photoash bulb electrically con-- nected in series with each other and in parallel with said. main condenser and main photoflash bulb, and a sup-A plementary resistor electrically `connected in parallel withA said supplementary bulb in bypass relation thereto, said.

supplementary photoash unit having no separate source of current of its own, said photoflash bulbs being of the combustible and consumable type, and all of said con-- densers being of the electrolytic type.

1l. A construction as defined in claim 10, further including an electric switch in the series connection between. said source of current and said main condenser, a bulb socket for said main phototlash bulb, and means operated by insertion of said main bulb in said socket for closing said switch and operated by removal of said main bulb` from said socket for opening said switch.

(References on following page) v,Schwartz, .May 19,1953