US2980879A - Lamp socket for photoflash units - Google Patents

Description

Jersey Filed Aug. 26, 19 59, Ser. No. 836,183

2 Claims. (Cl. ass-45 The present invention relates to a photoflash unit for photographic cameras and particularly to a lamp socket for such a unit which is adapted to accommodate a midget type flash lamp having a base provided with recesses therein to retain the base in the socket in contact with appropriate electrical elements. More particularly, the socket is adaptedto accommodate a flash lamp of the type designated as AG-l, having a flattened base formed as a part of the lamp bulb and provided with oppositely disposed transverse recesses on the fiat sides of the base and with terminal wires on the end of the base. Upon being simply pressed into the socket, the terminals on the base of the lamp are brought into proper contact with the appropriate electrical connections and the lamp is retained in the socket in such position until released by means of a push button. Upon being released, the lamp.

is ejected from the socket by a spring action and without the necessity of the operators havingto grasp the hot lamp.

One object of the present invention is to provide a lamp socket for a photofiash unit adapted to accommodate midget type flash lamps of the type designated as AG-l, which permits the photographer to readily insert the flash lamp axially into the socket by a straight thrust.

Another object of the invention is to provide such a socket whereby the used lamp may be ejected from the socket without the necessity of its being touched by the photographer.

Still another object of the invention is the provision of such a socket of simplified construction which lends itself to inexpensive fabrication from stamped metal and molded plastic components.

The novel features that we consider characteristic of the invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and its method of operation, together with additional objects and advantages thereof, will best be understood from the following description when read in connection with the accompanying drawings in which:

Fig. 1 is a perspective rear view of the photoflash unit with the cover removed to show the Construction of the socket in accordance with a preferred embodiment of the present invention. I

Fig. 2 is an enlarged partial sectional side view of the socket assembly showing the lamp base and the portions of the socket in engagement therewith.

Fig. 3 is a front elevational view of the flash lamp.

Fig. 4 is a side elevational view of the flash lamp.

Fig. 5 is a top plan view of the lower socket member.

Fig. 6 is a rear elevational view of the lower socket member.

Fig. 7 is a bottom view of the lower socket member.

Fig. 8 is a top plan view of the upper socket member.

Fig. 9 is a rear elevational view of the upper socket member.

Fig. 10 is a bottom view of the upper socket member.

Fig. 11 is a rear view of the lamp base guiding member.

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Fig. 12 is a side elevational view of the lamp base guiding member.

Referring now to the drawings, throughout which like reference characters refer to corresponding parts, the photofla'sh unit of which the socket of the present invention forms a part comprises a housing 18 of the shape shown in Fig. l, which is adapted to contain all of the electrical components and which is molded from a plastic material for insulation purposes. The rear of the housing is provided with a flat metal cover, not shown, which is removable to change the batteries, not shown, which are located in side-by-side relation in the lower portion of the housing to provide the power source for firing the lamp.

As is customary in the art, this photoflash unit is adapted to be detachably connected to the side wall of a camera and to be electrically connected into the flash synchronizing switch controlled by the camera shutter. To this end the photoflash unit includes locating pins 11 and 12 and an attaching screw 13, which engage corresponding holes in the wall of the camera. Pins 11 and 12 merely engage locating holes in the camera body while attaching screw '13, which is rotated by means of knob 14, engages a threaded hole in the camera body to force pins 11 and 12 completely into their respective holes. Attaching screw 13 and pin 12 form parts of the electrical circuit between the flash switch in the camera and the photoflash unit components, whereas pin 11 is merely a locating pin and forms no part of the electrical circuit.

Pin 12 has a press fit through the wall of the photoflash unit and is supported at its inward end by a slot in a projection formed on the inside surface of the opposite wall. The power source consists of two type AA batteries adapted to be placed in the photoflash unit in side-by-side relation and with both bases downward. The thickened central portion 15 of pin 12 engages and supports the base of the innermost battery. The batteries are electrically connected in series by a member '16, comprising a piece of sheet metal cut and bent to form a flat section 16a located within the lower portion of housing 10 against the front wall thereof, a second flat section 161; located against the side wall of the housing, and contact straps 16c and 16d, adapted respectively to engage and electrically connect the top terminal of the innermost battery and the base of the outermost battery. Member 16 is retained within the housing by projections 17, two of which are shown in Fig. 1, which gouge into the plastic walls of the housing. The top terminal of the outermost battery is engaged by the lower surface of the right end 41 of lower socket member 18, as viewed in Fig. 1. This member in turn, contacts one of terminals 40 of the flashlamp 29 as will be described later. To complete the circuit, attaching screw 13, which is electrically connected to pin 12 through the flash synchronizing switch within the camera, is in electricalcontact with the lower end 47 of upper socket member 21, which, as will be more fully described later, contacts the other terminal on the base of the flash lamp. Thus, the closing of the flash synchronizing switch between attaching screw 13 and pin 12 closes the electrical circuit to fire the flash lamp.

The lamp socket of the present invention is located in the upper, offset and rounded end of the photoflash unit housing which is molded to form a hollow casing provided with a circular lamp opening in the front wall thereof. A reflector 22 is located on the frontal side of the housing unit concentric with the lamp opening and is fixedly attached to the photoflash unit by means of a funnel shaped metallic mounting sleeve, not shown, pressed into the reflector from the front side thereof and extending through the lamp opening in the housing. The rear portion of the reflector mounting sleeve is provided with a plurality of tabs, not shown, which are bent over to secure the sleeve and the reflector to the housing.

32 of the lower socket member.

accommodate the increase the resilience of the member. '47 on the upper socket member is illustrated at the lower plate 47 is held against the inside wall wall of the socket housing with notch 29, in the edge of Q the disk. The rectangular opening 24 in disk 23 is tapered outwardly toward the frontal surface of the disk to aid in guiding the base of the lamp through the opening, as is best illustrated in Fig. 2.

The lower socket member 18 is formed outfof a single I I piece of fiat metal sheet stock. The details of this member are best seen in the three views shown in Figs 5, 6,

and 7. This member is secured to the front wall of the socket housing by means of a screw, not shown, extend-- ing through hole 28 in the mounting wing 30 ofthe lower socket member. An elongated hole .31, below the mounting hole 28 engages a corresponding projection 27, the lower end of which is visible in Fig. 1, on the front wall of the socket housing to prevent the rotation of the lower socket member around its mounting screw. Extension 32 of the lower member is located behind the lower edge of the rectangular opening 24 in disk 23 and parallel to the lower side of the bulb base 25. The lower surface 33 of the left end of this extension is supported by a projection, not shown, on the inner side wall of the socket housing while the opposite surface 34, of the same end of extension 32 abuts against projection 35 on disk 23. A semi-circular projection 36 is formed on surface This projection is bent upwardly toward the lamp base and the edge portion 26 of extension 32 is bent downwardly to form a continuation of the plane of the upper surface of projection '36. The top surface of the edge portion 26 thereby coopcrates with the tapered profile of opening 24 in disk 23 to guide the bulb into the socket as illustrated in Fig. '2. The lower contact strap 37 is formed as a part of the lower socket member, as shown, and is of sufiicient length to provide a resilient contact between the enlarged contact area 38 of the strap and the corresponding terminal wire 40 on the base of the bulb. The resilient action of the strap serves to maintain an intimate contact with the "terminalwire of the bulb and also, in cooperation with the similar strap carried by the upper socket member, to

bulb retaining eject the bulb from the socket when the means are released. The extreme right end 41 of the lower socket member is formed to provide the contact and support for the top terminal of the outermost battery in the photoflash unit. A square hole 4-2, is provided in the top surface of the lower socket member to ejector pin, as will be later described. Win-g 43, at the rear of member 18, is provided with a. hole 44, which is engaged by a screw, not shown, to secure the removable cover plate in position and with a hole 45, which provides access to the screw that secures the lower socket member to the front wall of the housing.

The upper socket member 21 is shown in three views in Figs. 8, 9, and 10. This upper socket member is likewise formed from a single piece of fiat sheet metal stock but an addition stiffening spring 46, is also provided to Mounting plate right end thereof and, in addition to supporting the member, forms an electrical connection between the upper contact member and mounting screw 13. 'Mounting of the unit by means of a nut 48, or by other suitable means associated with the end of locating pin 11. In order to insure that the flash lamp cannot be discharged by the accidental shortingof screw 13 to pin 12 when the unit is not-attached to the camera, a light spring washer 50 is provided below the head 51 of screw 13 to prevent conmolded on the inner surface of housing 10 bears against the topsurface of spring 46 and formsa fulcrum to restrict the efiective length of the resilient upper portion of the upper socket member. Leaf spring 46 is attached to the top surface of the upper contact member by a rivet 56, and is prevented from rotating about the rivet by the engagement of a tab 57 on the end of the spring with a hole 58 in the upper socket member. The relative position of the upper and lower contact members is shown in Figs. 1 and 2. In their assembled relation, the upper cont-act member is urged downwardly toward the lower contact member by the resiliency of the member itself and by the additional tension of leaf spring 46. An insulating washer 59 is located between the upper surface 60 of the lower contact member and the lower surface 61 of the upper contact member to prevent any electrical connection between these two members. Washer 59 is retained in position by the ejector pin 62 which passes through the washer. The ejector pin passes through square hole 42 in the lower member and through washer 59 and a projection on the end of the pin enters hole 63 in the upper member. The lower end of the ejector pin passes through and is slidably supported in a hole in the wall of housing 10 to provide a push button accessible from outside the housing. A shoulder on the pin abuts against the lower side of the upper contact member so that the vertical movement of the pin will bend the left end of the upper socket member upwardly and away from the lower socket member. To retain the ejector pin in its movable position within the socket housing, an annular collar 64 is formed about the base of the pin and engages the inner surface of the socket housing about the periphery of the hole through which the push button end 65 of the pin extends through the wall of the housing. As the upper member is displaced,

over projection 36, thus ejecting the bulb from the socket.

The sloping frontal aspect of the leading edges of the socket members and of the retaining projections, as seen in profile in Fig. 2, causes the upper contact member to be displaced against its spring tension by the insertion of the bulb and without the necessity of pressing the ejector button, but prevent the bulbs being moved except by means of depressing the ejector button.

From the foregoing description of the invention it is believed apparent that the disclosed lamp socket for AG-l type photoflash lamps is convenient and foolproof in its operation. The design is readily adaptable to low cost production techniques because of the usage of molded plastic and stamped metal components. Furthermore, the socket is conducive to easy assembly since no soldered or wire connections are used. While the socket illustrated isshown in connection with a particular type of photoflash unit, it ispointed out that its use is not limited to such a photoflash unit but that it can be used equally well on photoflash units having different types of power sources than that disclosed and on photoflash units which are used separately from the camera and which are connected to the flash synchronizer switch associated with the camera shutter through the use of separate lead wires or by other means, rather than being mounted dircctly. on the'camera body-and electrically connected to the synchronizer switch by means of such mounting.

Although we have shown and described certain specific embodiments of our invention, we are fully aware that certain modifications thereof are possible. Our invention, therefore, is not to be limited to the precise details of construction shown and described but is intended to cover all modifications coming within the scope of the appended claims.

We claim:

1. A lamp socket adapted to releasably retain a flash lamp having a flattened base including a first transverse retaining recess in the first fiat side thereof, a second transverse retaining recess opposite said first recess in the second flat side thereof, a first electrical terminal located on the end of said base and a second terminal located on said end of said base and spaced from said first terminal, said socket comprising a housing provided with an opening in the front surface thereof adapted to accommodate the flattened base of said flash lamp when said lamp is inserted axially thereinto, a first stationary socket member formed from a single piece of sheet metal and so located within said housing as to be adjacent and parallel to said first flat side of said base when said base is located in said socket, said first member including a first projection thereon adapted to engage said first transverse retaining recess when said base is so located and a resilient contact strap adapted to engage and to exert an axial thrust against said first terminal when said base is so located, a second socket member comprising a leaf spring, within said housing, one end of said spring being fixedly attached to said housing, the opposite free end of said spring including a second projection thereon adapted to engage said second transverse retaining recess in said base when so located, said arm being biased toward a first position wherein said second projection is in engagement with said second transverse retaining recess in said base when so located and being movable to a second position wherein said second projection is spaced from said first projection by a distance greater than the thickness of said flattened base, a resilient contact strap formed as an integral part of said spring and adapted to engage and to exert an axial thrust against said second terminal when said base is so located, and means associated with said spring and accessible from outside said housing to move said free end of said spring from said first position to said second position to release said base so located in said socket.

2. A lamp socket adapted to releasably retain a flash lamp having a flattened base including a first transverse retaining recess in the first flat side thereof, a second transverse retaining recess opposite said first recess in the second flat side thereof, a first electrical terminal located on the end of said base and a second terminal located on said end of said base and spaced from said first terminal, saidlsocket comprising a housing, one surface of which is provided with a substantially rectangular opening through which the base of said fiash lamp is adapted to be axially inserted when properly oriented relative thereto, a first stationary socket member formed from a single piece of sheet metal and so located within said housing as to be adjacent and parallel to said first fiat side of said base when said base is inserted into said socket, said first member including a first projection thereon adapted to engage said first transverse retaining recess when said base is so located, and a resilient contact strap adapted to engage and to exert an axial thrust against said first terminal when said base is so located, a second socket member comprising a leaf spring within said housing, one end of said spring being fixedly attached to said housing, the opposite free end of said spring including a second projection thereon adapted to engage said second transverse retaining recess when said lamp base is inserted into the socket, said free end being biased toward a latching position, wherein said second projection is adapted to drop into said second transverse retaining recess in said lamp base when said lamp base is inserted into said socket, and being movable transversely of said opening to an unlatching position wherein said second projection is moved out of said second retaining recess, a second resilient contact strap formed as an integral part of said leaf spring and adapted to engage and to exert an axial thrust against said second terminal when said base is so located, and means associated with the free end of said spring and accessible from outside said housing to move said free end of said spring from said latching position to said unlatching position to release said base and permit said lamp to be ejected from said socket by the spring action of said resilient contact straps.

Wilkinson May 6, 1952 McKee et a1. Aug. 19, 1958

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