US2691143A - Lamp socket adapter - Google Patents

Description

Oct. 5, 1954 e, R. LAWSON LAMP SOCKET ADAPTER Filed Feb. 19, 1954 inventor: Guszfaf RLau/s Q9 WK ms A aom Patented Oct. 5, 1954 UNITED S'EA'Iiiiii PATENT ()FFICE LAMP SGCKET ADAPTER New York Application February 19, 1954:, Serial No. 411,337

6 Claims.

The present invention relates to an adapter which may be installed in an electric socket so that a smaller size lamp than the lamp for which the socket was designed may be mounted in the socket. This invention pertains more particularly to a lamp socket adapter for use with photofiash lamps such as are employed in photography, although it should be appreciated that the invention is not restricted in its use to flash lamps and flash attachments.

One of the limitations of flash photography in the past has been the necessity of carrying bulky equipment in the form of a flash attachment and a quantity of flash lamps in addition to the camera. Photoflash lamps have a burning life of only a few hundredths of a second; therefore, they must be replaced after the taking of each picture. It becomes very cumbersome to carry eight or twelve flash lamps for each roll of film.

Recently there has been developed a new and improved flash lamp which is of a smaller size than those heretofore available on the market. This new flash lamp is similar in size to the smallest Christmas tree lamp and about onehalf of the size of its immediate forerunners. With this undersized lamp, it will be relatively easy to carry eight or twelve of these new lamps because they take up such little space. This new lamp development makes possible for the first time the construction of more compact flash attachments than have been previously available on the market. Since these new flash lamps are of reduced size, they do not fit the lamp sockets of the present day flash attachment equipment. Therefore, new flash units to accommodate the new lamps must be designed for the future, while adapters will have to be used for fitting the smaller size lamps into the lamp socket openings of the flash attachments now in use.

Accordingly, the principal object of this invention is to provide an adapter for a lamp socket so that an undersized lamp may be mounted in the socket.

A further object is to provide a readily removable lamp socket adapter for flash attachments used in photography so that two diflerent sizes of flash lamps may be used alternatively in the same flash attachment.

A further object is to provide a novel lamp socket adapter having a coiled spring contact means.

A further object is to provide in a lamp socket a novel coiled spring contact means.

A further object is to provide an improved 2 method of installing a spring in an apertured wall.

A still further object is to provide in a lamp socket or socket adapter a trigger mechanism for cooperation with a lamp to hold it in place and to release it from the socket or the adapter, as the case may be.

The present invention as herein described is embodied in one instance in a lamp socket adapt er comprising an outer metal shell adapted for insertion into a lamp socket, the shell being open at one end and provided with an aperture at its opposite end. Within this shell is mounted a cup-shaped insert of insulating material. This insert is open at its outer end to receive a lamp base therein. There is an aperture in the inner end of the insertwhich is in alignment with the aperture in the shell. A coiled compression spring having a reduced central portion located within the said apertures is provided in adapter so that it serves the multiple function of carrying current, of making good electrical contact with the live contact of the existing flash equipment, and also of providing the ejecting means for the spent flash lamp. A trigger is also located within the adapter to engage the base of the flash lamp for making electrical contact with it and for locking the lamp in position. The free end of the trigger extends outwardly of the adapter and is used as a lever to disengage the trigger from contact with the lamp.

This invention also includes a novel method of inserting the coiled compression spring in an aperture such as the aperture through the base of the adapter. duced central portion and large outer ends, one end being axially open and the other end being substantially closed. To insert the spring into an aperture which is smaller than both ends of the spring, the spring is located in the adapter with its closed end at the entrance to the aperture, and a rod is thrust into the open outer end of the spring until the end of the rod engages the opposite closed end of the spring. By applying a pushing force with the rod, the end of the spring is elongated thereby reducing its diameter, so that the turns of the spring will thread their way through the aperture until the central portion of the spring is confined within the aperture.

Likewise, the novel spring of this invention may be incorporated in a lamp socket which is designed to receive the undersized lamps. The lower or back wall of the socket is similar in design to the lower or apertured wall of the insert of the socket adapter.

The coiled spring has a re My invention will be better understood from the following description taken in connection with the accompanying drawing, and its scope will be pointed out in the appended claims.

In the drawing:

Fig. l is a partial sectional elevational view of the complete lamp socket adapter embodying my invention with a lamp mounted therein.

Fig. 2 is a top plan view of the lam socket adapter of Fig. l with the lamp removed.

Fig. 3 is a sectional view of the insert taken generally on the line 33 of Fig. 2 ShOWing how the spring of this invention is positioned within the insert of the adapter before the spring is forced through the aperture in the end of the insert and confined therein.

Fig. 4 is a sectional view similar to Fig. 3 show ing how a rod is used to elongate one end of the spring to temporarily reduce its diameter so that i it may slip through the aperture in the insert.

Fig. 5 is an exploded view of the socket adapter of Fig. l'with the lamp removed.

Fig. 6 is a partial cross-sectional view of a combined lamp socket and reflector for a flash attachment.

Referring in detail to the drawing, 10 represents the metal shell of a lamp socket adapter which is similar in size and shape to the bayonet base of the flash lamps now available on the market, whereby the adapter can readily be inserted into existing sockets for such lamps. This shell I9 is provided with a pair of oppositely disposed bayonet pins or protrusions l l which are used to cooperate with the lamp socket of a flash attachment to guide and hold the adapter therein. The shell IE) is provided with an aperture I2 in' its base portion. Mounted within the shell is a cupshaped insert l3 of insulating material which is provided at one end with an outer boss 14 that is seated in the aperture l2 of the shell. The boss I4 has a centrally disposedaperture l5 communicating with the inner compartment of the insert. The upper end of the shell 10 as well as the upper end of the insert [3 are open to accommodate the lamp base I6 of a lamp I! therein.

A coiled copper wire spring I 8 is mounted within the adapter to provide an ejecting means for a lamp that is to be removed, and also to carry current as the center contact of the adapter for making electrical connection with the center contact at the base of a lamp. The spring I8 is of novel design, the two ends of the spring being. both larger in diameter than the center portion. The center portion [9 of the spring comprises a plurality of turns of equal diameter, which turns are closely wound so that when the lamp is inserted in the adapter and the adapter in the socket of a flash attachment, there is no spring action in said portion. The lower end of the spring presents a shoulder 2| of one or more turns of larger diameter than the diameter of the aperture l5 through the bottom of the insert. The end 20 of the spring is also tapered from the shoulder portion 2| to a reduced end section 22 which is substantially closed. The opposite end 23 of the spring has spaced turnsat a greater pitch than the turns of the remainder of the spring. The reason for this is that the portion 23 of the spring is designed to be compressed when a lamp I! is forced into the adapter so that the spring portion 23 stands ready to act as the ejecting means for the lamp.

Turning now to Fig. 3 and Fig. 4 of the drawing, the novel method of this invention of locating the spring IS in the adapter will become apparent. The spring I8 is first placed over the aperture [5 in the insert [3 with the short tapered end 28 located partially within the aperture. A short length of rod 2 of a diameter in the order of about {a of an inch is next inserted through the spring at the end portion 23 until the end of the rod is seated on the closed end section 22 of the spring. In order to facilitate the following operation, the upper edge 25 of the aperture I5 is countersunk. When a force is directed down on the rod 24, the tapered end 20 of the spring will begin to elongate as is seen in Fig. 4, thereby reducing the diameter of the end portion 20 until the eifective size of the shoulder 2| of the spring is smaller than the aperture I5 in the insert. When the diameter of the end portion 20 of the spring is so reduced, the pushing force supplied by the rod 2A to the end section 22 of the spring forces the spring to move through the aperture until the large portion 23 of the spring engages the base portion of the insert. Thus, the center portion [9 is locked or confined within the aperture as is shown in Fig. l, for when the rod is withdrawn, the end portion 20 of the spring returns to its original shape. When the spring is located within the aperture, it, in effect, constitutes two springs. The inner portion 23 of the spring acts as an electrical contact for a lamp as well as the ejecting means to discharge the lamp after it has been used, while the outer end 20 of the spring is adapted to make good electrical contact with the live contact of the flash attachment.

In order to hold the flash lamp H in the adapter, a trigger 26 is used. The lower end 2? of the trigger is positioned in a recess 9 in the outer surface of the insert I3 and in contact with the inner surface of the shell Ill. The central portion of the trigger 26 is normally biased inwardly of the adapter and is provided with a latch portion which may be a lancing or a rivet means for engagement with the base of the lamp H. The lamp base i6 of the lamp I1 is provided with a circumferential groove 29 in place of the usual bayonet pins or screw threads. Accordingly, it is not necessary to accurately position the flash lamp relative to the slots in the socket, nor is it necessary to screw the lamp into the lamp socket. The cup-shaped insert l3 has an outer bore of a diameter to accommodate the base of a lamp as well as an inner bore 4| of reduced cross-section. There is a shoulder or circular ledge 42 joining the large bore 40 with the smaller bore 4|. This ledge 42 is so located that it serves as a stop means for the inward movement of the lamp. As a result of this arrangement, the groove 29 of the lamp base cannot move inwardly past the latch portion 30 of the trigger. Without this limiting feature, it might be possible to use a lamp to compress the end portion 23 of the spring to its maximum amount while at the same time moving the groove 29 of the lamp base inwardly and beyond the latch portion 39 of the trigger. If the downward force on the lamp were quickly released, the force of the spring might be strong enough to eject the lamp before the trigger could snap back to engage with the quickly moving lamp base.

To install the flash lamp I1, it is merely necessary to push the lamp into the socket adapter against the action of the end portion 23 of the spring I8 until the trigger engages with the circumferential groove 29 to lock the lamp in place. There is a vertically extending slot 3| in the upper wall of the insert i 3 so that the lower portion 21 of the trigger 26 is located between the insert it and the shell it], while the center portion of the trigger containing the latch 30 extends through the said slot 3! to engage the lamp base it. From the center portion of the trigger to its outer end, the trigger is located in the said slot 3i until it emerges from the shell l and extends at an angle so that it does not interfere with the flash lamp H. The rim 28 of the shell I!) is turned over as the final assembly operation to hold the insert firmly within the shell I0. As can be seen in Fig. 2, this rim 28 is not turned over in the area directly under the trigger as it emerges from the shell Hi. This is so because the travel of the trigger would be hampered unless sumcient clearance were made at this point.

The method of assembling the lamp socket adapter embodying this invention is simple and economical and easy to perform on a mass production basis. First, the compression spring it must be located within the insert i3 with the tapered end 25 of the spring positioned in the aperture [5. The rod 2 3 is thrust through the spring it until the end or" the rod engages the closed section 22 of the spring. A pushing force is applied to the rod 2 3 which elongates the end 25 of the spring, thereby reducing its eflective diameter as well as threads the large turns of the shoulder it through the aperture l5 until the central portion I9 of the spring is seated within the aperture. Then the trigger 26 is placed with its end portion 2i resting on the bottom wall of the shell it so that the insert it may be placed within shell it with the hollow bore I l extending through the aperture l2 of the shell. The rim 28 of the shell i9 is then turned over in the final assembly step so as to hold the parts together. The socket adapter is then ready for use.

The flash lamp ll is mounted in the socket adapter by merely pushing it into the interior of the adapter against the action of the spring until the latch is of the trigger 25 engages in the groove 29 of the lamp base 16. The socket adapter embodying my invention remains a permanent part of any flash attachment as long as these new and improved smaller size flash lamps are to be used. To withdraw the adapter from the flash attachment, it is merely necessary to disconnect it in the same manner as if it were one of the flash lamps designed for the flash attachment. Therefore, with this invention, it is possible to use either the size lamps which were designed for the flash attachment or it is possible to install this socket adapter and take advantage of the convenience and low cost of the smaller size flash lamp.

As will be noted in the exploded view of the socket adapter of Fig. 5, the lower end 21 of the trigger 25 is formed at an acute angle. When the trigger is placed in the adapter, the insert 13 acts against the lower portion Zl to enlarge the acute angle so that it is substantially a right angle. The insert it is assisted in holding the trigger in this relation by the rim 28 of the shell it which is turned over as the final assembly operation. Because the trigger is stressed in this manner, it is normally biased inwardly of the large bore 40 of the insert [3. Consequently, it will always be in position to engage with the groove 29 of the lamp base 16.

Fig. 6 of the drawing illustrates a combined lamp socket and reflector which has been designed to receive the undersized lamps. In this view is shown lamp socket 5!], reflector 5|, flash lamp 52, and center contact 53, as well as the outer contact 54. The novel spring 55 is mounted in the apertured wall 56 of the socket to connect the center contact 53 with the center of the lamp 52. A trigger 5'! is fastened in the socket to connect the outer contact 54 with the side of the lamp base of the lamp 52. The spring 55 is mounted in the socket 50 in the same manner as the spring I 8 is inserted in the insert it of the above-mentioned socket adapter. Also, the cooperation between the lamp 52 with the spring 55 and trigger 51 is substantially the same as is found between the same parts of the socket adapter. In order to insert the trigger in the socket and to hold it in place, the hooked end 58 of the trigger is located within a complemental slot in the socket. Then the outer contact 54 is slipped between the trigger and the opposite wall 59 to wedge the lower end of the trigger 5! in place.

Consequently, having described my invention of a novel lamp socket and lamp socket adapter, it will be readily apparent to those skilled in this art that I have constructed a socket and socket adapter which have a minimum number of parts, which are simple in design and easy to manufacture as well as easy to assemble with a minimum amount of hand labor.

Modifications of this invention will occur to those skilled in the art, and it is to be understood, therefore, that this invention is not limited to the particular embodiment disclosed but that it is intended to cover all modifications which are within the true spirit and scope of this invention.

What I claim as new and desire to secure by Letters Patent in the United States Patent Ofiice 1. A lamp socket adapter comprising an outer shell of conductive material for insertion into a lamp socket, the shell being open at one end, and provided with an aperture at its opposite end, a hollow insert of insulating material fixed within the shell, said insert being provided with an apertured boss extending through the aperture in said shell, a compression spring located within the insert with the center portion of the spring extending through the said boss, the ends of said spring being larger than its center portion so that the spring is confined within said boss.

2. A lamp socket adapter comprising an outer metal shell for insertion into a lamp socket, the shell being open at one end and provided with an aperture at its opposite end, a hollow insert of insulating material mounted within the shell, said insert being provided with an apertured boss extending through the aperture in the shell, a coiled compression spring confined within the said boss, a trigger member fixed at its inner end between the shell and the insert with its outer end projecting to the outside of said assembly, the said trigger being adapted to releasably engage a lamp base mounted in the adapter.

3. A lamp socket adapter for flash lamps comprising an outer metal shell that is provided with a pair of oppositely disposed bayonet pins on its outer surface, the shell being open at one end and provided with an aperture at its opposite end, a hollow insert of insulating material mounted within the shell, said insert being open at its outer end to receive a lamp base therein, the insert being provided with an apertured boss extending through the aperture in the shell, a coil spring having a reduced central portion located within the said boss, the ends of said spring being enlar'ged to confinethe-springtherein so that the spring serves as the center contact for said adapter, a resilient trigger member fixed at its inner end between the shell and the insert with a portion of the trigger extending through a slot in the-walls of the insert to releasably engage a lamp base, the free end of the trigger extending to the outside of said adapter;

4. A lamp socket device comprising a hollow, lamp receiving housing open at one end and having an apertured Wall at its opposite end, a cornpressible, coiled contact spring having a central portion of reduced diameter positioned Within said aperture, the ends of the spring on both sides of the aperture being enlarged to confine the spring within the aperture, and releasable means within the housing for engaging a lamp base therein and making electrical contact therewith.

5. The method of mounting in an aperture a coil spring having a reduced central portion and enlarged outer ends, comprising the steps of thrusting a rod through one end of the spring until the endof the rod engages the opposite endof the spring, of placing the end of the spring against the said aperture and applying a force on the rod to elongate the end of the spring thereby reducing its effective diameter so that it slips into place with the central portion of the spring confined within the said aperture.

6. In a lamp socket adapter as recited in claim 1, a resilient trigger member fixed thereon with an inwardly extending latch portion for releasab-ly engaging a lamp base, and an outwardly extending free end portion which is adapted to be manually operated to release the lamp.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,316,231 Evans Apr. 13, 1943 2,457,930 Smith Jan. 4, 1949 2,462,530 Miller Feb. 22, 1949 2,565,492 French Aug. 28, 1951 2,578,296 Ernisse Dec. 11, 1951 2,602,879 Whelan July 8, 1952

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