US3487351A - Flash unit for use with plural types of flashbulbs - Google Patents

Description

30,1969 HANSEGBERT SCHMIDT 7,3

FLASH UNIT FOR USE WITH PLURAL TYPES OF FLASHBULBS Filed Dec. 2, 1966 IN V EN TOR.

HANS EGBERT SCHMIDT United States Patent 3,487,351 FLASH UNIT FOR USE WITH PLURAL TYPES OF FLASHBULBS Hans-Egbert Schmidt, Calw-Wimberg, Germany, assignor to Agfa-Gevaert Aktiengesellschaft, Leverkusen, Germany Filed Dec. 2, 1966, Ser. No. 598,739 Claims priority, application Germany, Dec. 7, 1965, Sch 39,431 Int. Cl. H011 27/00; G03b /02, 19/00 US. Cl. 339--33 8 Claims ABSTRACT OF THE DISCLOSURE A photographic flash unit having a socket member for receiving a plurality of different types of flashbulbs, a retaining element for holding the various flashbulbs in the socket, and first electrical contacts spaced from the retaining element for actuating a bulb mounted within the socket. The first electrical contacts are electrically connected with the retaining element to thereby permit the element to serve as an electrical contact as well as a retaining device when a given type of flashbulb is being used. When a multiple flashbulb unit is being used with the socket, the retaining element engages a portion of the unit to hold it in the socket, while the first electrical contacts engage second electrical contacts on an annular ring of the unit to permit sequential firing of the bulbs in the multiple unit. The multiple flashbulb unit is indexible with respect to the socket.

The present invention relates to flash units in general, and more particularly to improvements in flash units of the type which can be used in connection with multiple flashbulb holders known as Flashcubes.

It is already known to provide a flash unit with a socket which can receive the plug of a multiple flashbulb holder and is indexible with the holder to place successive unfired flashbulbs into requisite position for illumination of the subject. It is also known to construct the socket of a flash unit for use with multiple flashbulb holders in such a way that a properly inserted holder is rotatable with reference to the socket. Each flashbulb of the holder comprises two electric contacts which are carried by an annular base of insulating material, and such contacts are engageable by stationary terminals provided in the flash unit and forming part of a flash circuit which can be completed in response to closing of a conventional synchronizing switch. As a rule, the socket of the flash unit further comprises retaining means for yieldably holding the plug of a multiple flashbulb holder when the latter is properly coupled to the socket. Such flash units have gained Widespread acceptance by the manufacturers of cameras with built-in flash units and by manufacturers of discrete flash units which can be coupled to or used independently of cameras.

It is also known to construct a flash unit for use with one or more types of individual flashbulbs. Such individual flashbulbs normally comprise a vitreous plug which carries the electric contacts and can be inserted into the socket of a flash unit whereby the contacts engage complementary terminals of the flash circuit.

It is an important object of my invention to provide a novel and improved flash unit which can be used with two or more different types of flashbulbs, for example, with flashbulbs which are installed in a multiple flashbulb holder as well as with discrete flashbulbs.

Another object of the invention is to provide a flash unit of the just outlined character wherein the flash circuit requires minimal modifications in order to fire the flashbulbs of a Flashcube or individual flashbulbs.

A further object of the invention is to provide a flash unit which may be manufactured as a separate structural element or as a built-in part of a photographic camera and to provide the flash unit with an electric flash circuit which can fire at least two dilferent types of flashbulbs once such flashbulbs, or their holders, are properly coupled to the socket of the flash unit.

An additional object of the invention is to provide a flash unit wherein certain parts perform a novel function in addition to all such functions which the parts perform in conventional flash units.

Another object of my invention is to provide a flash unit which, in spite of its above outlined versatility, does not or need not occupy more space than a conventional flash unit which can take only one type of flashbulbs.

A further object of my invention is to provide a flash unit which can take different types of flashbulbs in any desired sequence and without necessitating any adjustments preparatory to switching from one type of flashbulbs to another.

A concomitant object of the invention is to provide a novel flash circuit for built-in or separate flash units.

Briefly outlined, one feature of my invention resides in the provision of a flash unit for use with plural types of flashbulbs differing from each other in the arrangement of electric contact pairs by which the flashbulbs are connectable into a flash circuit. The flash unit comprises a fixed or rotary socket adapted to be coupled with plural types of individual or grouped flashbulbs, a pair of retaining members for yieldably holding a flashbulb which is coupled to the socket, such retaining members being preferably constituted by leaf springs and consisting of current-conducting material, and a flash circuit including a pair of electric terminals each of which is electrically connected with one of the retaining members. The terminals are positioned to engage the contacts of a first type of flashbulb when such flashbulb is properly coupled to the socket, and the retaining members are positioned to engage the contact of a second type of flashbulb when such flashbulb is properly coupled to the socket. Thus, by the simple expedient of connecting the terminals in parallel with the retaining members, and by using current-conducting retaining members, the improved flash unit may be used with at least two types of flashbulbs. For example, the terminals may be engaged by successive pairs of contacts on the base of a conventional multiple flashbulb holder which is rotatable with or relative to the socket, and the retaining members may be engaged by the contacts of discrete flashbulbs of conventional design.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved flash unit itself, however, both as to its construction and its mode of operation, together with additional features and advantages thereof, will be best understood upon perusal of the following detailed description of certain specific embodiments with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view of a first type of flashbulb which can be used in connection with my improved flash unit;

FIG. 2 is a perspective view of a second type of flash bulb which can be used in connection with the flash unit;

FIG. 3 is a perspective view of a third type of flashbulb which can be used in connection with the flash unit; and

FIG. 4 is a fragmentary exploded perspective view of the improved flash unit.

Referring first to FIG. 4, there is shown a flash unit which comprises a socket 4 having a centrally located opening 5a surrounded by a ring 5. The axis of the opening 511 is indicated by a vertical line 3. The socket 4 is fixed to a housing or support 30 whose interior accommodates two retaining members 1 and 2 here shown as leaf springs. These springs consist of current-conducting material and serve to retain a portion of a flshbulb or a portion of a multiple flash bulb holder when the latter is properly coupled with the socket 4. FIG. 4 shows the flash unit in exploded perspective view, i.e., the springs 1, 2 are. shown at a level below their normal position in which they are located immediately beneath or close to the socket 4. The opening 5a may receive the downwardly extending plug 6 of a multiple. flash bulb holder 7, known as Flashcube, which is illustrated in FIG. 3 and comprises four equidistant flashbulbs 107 each located in front of a reflector 107a. The opening 5a is large enough to permit passage of four teeth 8, 9, 10, 11 which are provided on the plug 6 and have mutually inclined front and rear surfaces. The front surfaces of two teeth which are located diametrically opposite each other will engage the inclined guide surfaces 14, 15 of the springs 1, 2 when the plug 6 is introduced into the opening 5a whereby the springs 1, 2 yield and permit further inward movement of the plugs. The inclined rear surfaces of two teeth (8 and 10 or 9 and 11) then enter two detent notches 12, 13 which are respectively provided in the springs 1, 2 just below the guide surfaces 14, 15 whereby the springs are free to move toward each other and to yieldably hold the plug 6 in fully inserted position in which the multiple flashbulb holder 7 is properly coupled to the socket 4 and one of the flashbulbs 107 faces the subject.

The multiple flashbulb holder 7 further comprises an annular base or skirt 18 of insulating material which surrounds the plug 6 and can extend into a circular opening 511 of the socket 4 when the plug 6 is properly retained by the springs 1 and 2. The base 18 carries four pairs of electric contacts 18a, 181), one pair for each of the four flashbulbs 107. These contacts are connected with the filaments of the respective flashbulbs. The contacts 18a, 18b of that flashbulb which face the subject (the subject is assumed to be located to the left of FIG. 4) then engage with a pair of electric terminals 16, 17 which form part of the flash circuit and are preferably constituted by two leaf springs which extend into cutouts 5c, 5d of the socket 4. In this way, the flashbulb 107 which faces the subject can be fired in response to closing of the conventional synchronizing switch, not shown. Upon firing of that flashbulb 107 which faces the subject, the entire multiple bulb holder 7 is caused to make a quarter turn so that the next unfired flashbulb faces the subject. During such turning of the. holder 7, the base 18 rotates about the ring 5 of the socket 4 and the springs 1, 2 first move away from and thereupon toward each other until the detent notches 12, 13 receive the rearsurfaces on the other pair of teeth (8 and 10 or 9 and 11). The flash unit is then ready to fire the next flashbulb 107. The same procedure can be repeated two more times whereupon the holder 7 is replaced by a fresh holder or by a holder which contains at least one unfired flashbulb 107.

It will be seen that, when the flash unit of FIG. 4 is used in connection with multiple flashbulb holders 7 of the type shown in FIG. 3, the springs 1 and 2 merely perform a retaining and guiding function to insure convenient introduction of the plug 6 and satisfactory retention of a properly coupled multiple. flashbulb holder.

The flash unit of FIG. 4 may be constructed as a separate entity or as a built-in part of a photographic camera. In the latter instance, the support constitutes the top wall or the side wall of the camera housing, depending upon whether the holders 7 are to be attached laterally or on top of the camera housing. This flash unit further comprises an ejector here shown as a plunger 27 which is reciprocable into and from the central opening 5a of the socket 4. When moved from the retracted position of FIG. 4 (arrow 28), the plunger 27 will travel upwardly along the axis 3 and will expel the plug 6 from the opening 5a by overcoming the retaining action of springs 1 and 2.

This plunger is preferably biased to retracted position so that it automatically returns when released by the operators finger.

In accordance with an important feature of my present invention, the flash unit of FIG. 4 may be utilized with multiple flashbulb holders 7 or with analogous multiple flashbulb holders, as well as with individual flashbulbs 21,

22 of the type shown in FIG. 1 or 2. This is made possible by the provision of conductors 19 and 20 which respectively connect the retaining springs 1 and 2 with the terminals 16 and 17 so that the springs constitute two additional terminals of the flash circuit and the flash unit can also fire a flashbulb whose contacts engage with the springs 1 and 2. In the illustrated embodiment, the conductors 19 and 20 are flexible wires so that the terminals 16, 17 are movable with reference to the springs 1 and 2, or vice versa. These conductors may be permanently or detachably connected with the terminals and/ or with the springs, and it is also possible to provide two rigid conductors which provide stable and inseparable electrical connections between the terminals 16, 17 and springs 1, 2. Alternatively, the parts 1, 16 and 2, 17 may be made of two pieces of sheet metal or the like so that no welding, soldering or other connecting is needed. The plug 6 invariably consists of insulating material so that the utilization of current-conducting retaining springs cannot result in premature or accidental firing of flashbulbs in the holder 7.

The flashbulb 21 of FIG. 1 comprises an envelope and a base provided with a projection or plug 21a of vitreous or other suitable insulating material which can be introduced into the opening 5a of the socket 4. The plug 21a carries two wire- like contacts 23, 24 which engage the springs 1, 2 or 2, 1 when the flashbulb 21 is properly coupled with the socket 4 so that it can be fired in response to closing of the synchronizing switch. The terminals 16, 17 are then ineffective and need not be engaged by any part of the flashbulb 21. If the latter does not have its own reflector, the operator may attach to the support 30 a suitable reflector 29 which is shown in FIG. 4. This reflector can be attached or withdrawn by moving in directions indicated by arrow 29a. It is further preferred to mount the reflector 29 in such a way that it can be adjusted in an arcuate path about the axis 3 to provide special illuminating effects if the operator does not wish to direct the artificial light squarely upon the subject or scene. The directions of angular displacement of the reflector 29 are indicated by arrow 2%. For example, the support 30 may have an arcuate slot 3011 which receives the lower edge of the reflector 29 with at least some friction. Of course, it is also possible to provide a permanent connection between the reflector 29 and support 30. When the flashbulb 21 has been fired, the operator will again displace the ejector plunger 27 (arrow 28) whereby the plunger expels the plug 21a from the opening 5a. The plug 21a may be provided with suitable ribs, teeth or the like which enter the detent notches 12, 13 when the flashbulb 21 of FIG. 1 is properly coupled to the socket 4.

FIG. 2 illustrates a third type of flashbulb 22 which again comprises an envelope and a plug 22a carrying two electric contacts 25, 26 which can be engaged by the springs 1, 2 when the plug 22a is fully inserted into the opening 5a of the socket 4. The triangular portions defining the notches 12, 13 then snap into two transversely extending grooves 22A, 22B of the plug 22a to insure satisfactory retention of the flashbulb 22. The plunger 27 can eject the plug 22a in response to upward movement.

The configuration of the retaining springs 1 and 2 is such that they can properly engage the contacts 23, 24 or 25, 26 even if the distance between the contacts 23, 24 is different from the distance between the contacts 25, 26. Such differences can be compensated for by flexing of the springs 1 and 2. No adjustments are necessary if the operator decides to replace the multiple flashbulb holder 7 with the flashbulb 21 or 22, or vice versa. If desired,

the flash unit may be provided with an indexing mechanism which can turn the multiple flashbulb holder 7 through angles of 90 degrees or a multiple of 90 degrees. If the flash unit of FIG. 4 is built into a camera, the indexing mechanism for a multiple flashbulb holder can receive motion from the film transporting mechanism or from the shutter release.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features which fairly constitute essential characteristics of the generic and specific aspects of my contribution to the art.

What is claimed as new and desired to be protected by Letters Patent is:

1. A flash unit, comprising socket means having an outer side, an inner side and provided with an opening; current-conducting retaining means adjacent to the inner side of said socket means in registry with said opening; first electrical contact means electrically connected with and spaced from said retaining means; a multiple flashbulb holder having a portion insertable into said opening from the outer side of said socket means to engage said retaining means, said holder being indexible with reference to said socket means and further comprising a plurality of second contact means arranged to engage said first contact means one after the other in response to indexing of said holder while said portion thereof engages with said retaining means; and at least one flashbulb usable interchangeably with said holder and having a portion provided with third contact means, said last-mentioned portion being insertable into said opening from the outer side of said socket means to thereby engage said third contact means with said retaining means and to thus electrically connect said third contact means with said first contact means.

2. A flash unit as defined in claim 1, wherein said retaining means is separable from said first contact means.

3. A flash unit as defined in claim 1, wherein said totaining means is rigidly connected with said first contact means.

4. A flash unit as defined in claim 1, wherein at least one of said retaining means and said first contact means is movable with reference to the other thereof.

5. A flash unit as defined in claim 1, wherein said retaining means comprises detent means for said portions of said holder and said flashbulb.

6. A flash unit as defined in claim 1, wherein said retaining means is provided with guide surfaces for said portions of said holder and said fiashbulb during insertion of such portions into said socket means.

7. A flash unit as defined in claim 1, wherein said retaining means comprises leaf springs.

8. A flash unit as defined in claim 1, wherein said first contact means comprises leaf springs.

References Cited UNITED STATES PATENTS 2,662,968 12/ 1953 Saraber 240-13 2,982,936 5/1961 Pennock et al 339-33 3,353,465 11/ 1967 Peterson et al. -115 FOREIGN PATENTS 1,344,772 10/ 1963 France.

NORTON ANSHER, Primary Examiner FRED L. BRAUN, Assistant Examiner US. Cl. X.R. 95-11; 240-13

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