US3262086A - Miniature lamp and receptacle therefor - Google Patents

Description

July 19, 1966 K. HERRMANN ETAL 3,262,086

MINIATURE LAMP AND RECEPTACLE THEREFOR Filed March 27, 1964 2 Sheets-Sheet 1 Fig.1b F

INVENTORS Karl Herrm nn Woltgang Ott By WP ATTORNEY July 19, 1966 K. HERRMANN ETAL 3,

MINIATURE LAMP AND RECEPTACLE THEREFOR Filed March 27, 1964 2 Sheets-Sheet 2 INVENTORS Karl Herrmann Wolfgang Ott 4. ATTO RN EY United States Patent 3 262,086 MINIATURE LAMP Abil) RECEPTACLE THEREFUR Karl Herrmann and Wolfgang Ott, Augsburg, Germany,

assignors to Patent-Freuhand-Gesellschaft fur Electrische Gliihlampen m.b.H., Munich, Germany Filed Mar. 27, 1964, Ser. No. 355,367 Claims priority, application Germany, Apr. 3, 1963, P 31,500 5 Claims. (Cl. 339176) This invention relates to electrically operated lamps and more particularly to miniature flash lamps, being concerned primarily with the base construction and contacts and to the receptacle with which the lamp may be utilized. The invention is involved with lamps having elongated tubular envelopes of small bulb volume usually in the vicinity of one cubic centimeter, and to lamps utilizing a glass base molded as an integral part with the glass bulb.

It is recognized there have been, in the prior art, lamps of larger capacity than the lamps involved in this invention, that have employed glass bases, such use being extended to larger-capacity photo-flash lamps. The known prior art lamp consists, for instance, of a nearly cylindrical appendage of the bulb somewhat flattened at sides thereof to provide two axially parallel opposite plane areas from which the current in-leads come out to be extended around the rounded parts of the base to function as the base contacts. Such a base, however, cannot be used for miniature photoaflash lamps because the hollow body forming the base represents a too great dead volume within the lamp.

Again it may be said that there is, in the prior art, a glass base for photo flash lamps of larger volume of well over one cubic centimeter capacity, which consists of a bulb having a flattened stem from the front sides of which the current in-leads project, those in-leads then being bent around different sides of the stem press like loops. Such a base, however, has the disadvantage of the length of the stem press serving as the glass base having to be quite long and actually, in the minimum size bulbs in which it is capable of use, has a length practically equal to or perhaps exceeding the length of the bulb portion of the lamp containing the light-producing medium. I

In its broad concept, the present invention proposes an improved construction of flash lamp of practical character for small-volume lamps.

Likewise a general aspect of the invention is directed to a lamp having an integral glass base with its bulb wherein the interior volume of the lamp is not increased at all by presence of the base therewith.

Somewhat more specifically, an object of the invention is to provide a miniature photo-flash lamp having an integral glass base of extremely short length in comparison to the total length of the lamp.

Corollary to the foregoing object, the invention is directed to the provision of a photo-flash lamp with integral glass bulb and base, the total length whereof is essentially and little more than the length of the bulb.

Of similar nature, the invention seeks and attains provision of a base of very small axial depth to perform at the same time the several functions of sealing the bulb, of providing seal for the in-leads, of securely positioning and protecting contacts for exterior electrical connections, of orienting the lamp in its introduction into a receptacle, and of providing means for retaining the lamp in a receptacle.

In conjunction with the foregoing object, the invention accomplishes the further objective of preventing shortcircuit between the receptacle terminals when inserting the lamp into a receptacle.

The invention also includes provision of a receptacle of room-saving character and minimum depth for utilization of the improved lamp.

Other objects, advantages, beneficial results and novel structural features will appear to persons skilled in the art to which the invention appertains, both by direct recitation thereof and by implication from the context, as the description proceeds.

Referring to the accompanying drawings, in which like numerals of reference indicate similar parts throughout the several views;

FIGURE 1a is a bottom end view of a flash-lamp constructed in accordance with the invention;

FIGURE 11) is a side elevation of the basal end of the lamp of FIG. 1a;

FIGURE 2 is a similar side elevation of a flash-lamp showing a modified construction of in-lead contacts;

FIGURE 3a is a diametric and axial section of a receptacle for use with flash lamps of FIGS. 1a, 1b and 2; and

FIGURE 3b is a top plan of said receptacle of FIG. 3a.

In the specific embodiment of the invention illustrated in said drawings, and first considering the showing thereof in FIGS. 1a and 1b, the flash-lamp comprises a hollow cylindrical glass bulb 1, which it will be understood is closed as usual at its upper end in accordance with usual practice by a domed end of glass in continuation of the glass side walls. The bottom end of the bulb is sealed with a glass flare 2 which, in the completed lamp, constitutes a glass base made integral with the bulb side wall as part of the fabricating process. That process is performed in a manner which produces a circumferential bulge or annular bead 3 the maximum diameter whereof is greater than the diameter of the cylindrical bulb 1, and coaxial with said bulb. Said flare, after being incorporated as an integral part with said bulb and de- (fined exteriorly by said bead, comprises the base for the lamp and for the most part is solid glass, as a consequence of which it does not increase the interior golume of the lamp beyond the normal capacity of the The said flare 2 is generally flat at its exterior under surface 2a except for a medial non circular protuberance 4, formed integrally therewith, of glass and projecting downwardly in a direction parallel to and including the axis 212 of the flare. Transversely to the axis 212, said protuberance 4 is shown as elongated but shorter in length than the diameter of the flare so does not extend to the periphery of the flare, said protuberance, furthermore, in cross-section being somewhat rectangular with semicylindrical ends. In a direction at right angles to the long transverse dimension of the protuberance, the same is of less width and the long side faces or flanks 4a thereof in conjunction with the generally flat surface 2a of the said flare, may be said to provide a declivity 26 at each flank of said protuberance 4 beneath tangential construction line 2d.

For an appreciation by way of specific example of approximate dimensions for a bulb of substantially one cubic centimeter capacity, the bulb may be in the close range of seven millimeters diameter and something over two centimeters in axial length, and used therewith is a bead of about two and four-tenths millimeters axial depth and having maximum diameter of about eight millimeters. The axial height or depth of the protuberance 4, and therefore the maximum depth of the associated declivities 20, might very properly be about one and a half millimeters, so that from the top of the flare 2 (where the bead 3 joins the bulb 1) to the bottom of the protuberance 4, the distance would be approximately three '2 a and nine-tenths millimeters. Said base may therefore be very justifiably referred to as relatively short or squatty as compared both to its diameter and to the length of the lamp.

Current in-leads and 6, the inner ends whereof protrude into the interior of bulb 1, are sealed in the said flare 2, and come out through the bottom surface thereof, each on an opposite side of protuberance 4 adjacent the opposite flanks 4a thereof and accordingly within what has been termed above as the declivities 2c formed by said surface and protuberance. Immediately at the point of exit of the said in-leads from said surface, they are bent down into engagement with said surface, preferably in a direction transverse to the protuberance so as to constitute electrical contacts 5a and 6a respectively. The contacts thus formed are separated by the protuberance 4 so as to be incapable of making a short circuit, and are in a protected location in said declivities 20. It may be mentioned here, that an exhaust tubulation 7, which may be metallic, extends from the interior of the bulb through the middle of the protuberance, and at proper sequence of manufacturing operations on the lamp, is sealed off in well-known manner, namely, after the lamp has gone through the exhausting and gas-filling stages. It may also be added here, that if so desired, one of the in-leads may be made tubular and used as the exhaust tubulation during manufacture of the lamp, and sealed off and then utilized as the in-lead and contact.

If so desired, the in-leads may have a construction indicated in FIG. 2, differing from that shown in FIGS. and 1b, by provision of in-leads 8 and 9 which remain straight, but with stubby protruding ends functioning as contacts situated in the above-described declivities 2c. Otherwise the foregoing description also applies to the showing of FIG. 2, inclusive of the suggestion of possible use of one of the in-leads as an exhaust tubulation.

Comment may also be made here, that while the foregoing description has arbitrarily referred to use of the invention with respect to miniature photoflash lamps, the invention is not to be understood as restricted thereto, as it is also applicable to miniature incandescent lamps, in which event the axial height of the glass base, constituted by flare 2 and protuberance 4, may be even less than the dimension mentioned above. Photoflash lamps generally have a gas filling under pressure, whereas miniature incandescent lamps are gas-filled at a lower pressure.

Flash devices, which include mounts for flash-lamp receiving receptacles and electrical circuit closing means for controlling energy from a suitable source, such as an electrical battery, are known in the prior art for use with flash-lamps heretofore available on the market. A special construction of receptacle for use in such devices is required for the flash-lamp of the present invention, and an example of a novel receptacle for this particular use is illustrated in FIGS. 3a and 3b.

In said showing of receptacle, the mount employed and designated by numeral 10a, is one provided with a hole 10 of appropriate size and shape symmetrical in opposite diametric directions with respect to a central axis. Two semi-circular clamping jaws 11, 12 adapted to close toward each other to provide a circular cavity therebetween coaxial with said hole 10, are mounted to slide laterally within the confines of the hole. To coordinate positioning and operation of said jaws 11, 12, the same are provided with an exterior annular groove 14a in which is located an elastic retainer such as the generally annular but expandable spring 14 shown. Said retainer is rendered expandable by provision of a radially outwardly directed loop 14b therein at one side and by a discontinuity at the opposite side, the discontinuity ends 140 being also projected radially outwardly. Said loop 14b and ends 140 project over a part 1012 of the mount 10a and will prevent depression of the jaws 11, 1 2 when the lamp is inserted. It may also be mentioned that the mount may be conveniently provided with clips 20, 21 projecting inwardly over the top edges of the jaws proximate to their facing edges for retaining the jaws permanently in the hole 10 of the mount.

The jaws 11, 12 are provided on their inner arcuate faces each with an inwardly projecting semi-annular shoulder 13 which, when said jaws are closed together, form a complete annular shoulder coaxial to and projecting into the central cavity within the jaws. The jaws are of electrically non-conductive material.

Projecting under said jaws 11 and 12 are resilient terminals, respectively 15, 16, of leaf-spring type, said terminals extending in a common diametric direction but separated from each other at their inner ends by a gap 17 commensurate with the width of the lamp protuberance 4. The width of said terminals 15, 16 is adapted to prevent the said lamp protuberance 4 from being pushed down therebelow anywhere but through said gap 17, and form upper surfaces on which said protuberance may be rotated until it registers with the gap. The distance in an axial direction from the under side of said shoulder 13 to the bottom plane of the jaws 11, 12 corresponds to the depth of the bulge or bead 3 of the lamp, so that when the downwardly exposed lamp contacts engage and depress the resilient terminals, said bead will be engaged under said shoulder. In that position of the lamp, the two jaws are resiliently pressed against the periphery of the base thereof rendering the shoulder 13 effective to retain the lamp from escape and maintain the in-lead contacts in resilient electrical engagement with the leaf- spring terminals 15, 16.

Too much bending of the leaf- spring terminals 15, 16, when the lamp is pressed into the receptacle, is prevented by provision of limiting supports 18, 19 thereunder. These said supports may conveniently be of stiffer material than the spring terminals, for example may be brass bars, and conform in width and length to the corresponding dimensions of the said terminals. Each spring terminal and its contiguous limiting support 18 or 19 extend radially outwardly beyond the jaw-receiving hole 10 and are secured by rivets 10d or in other suitable manner, to the flash device mount 10a thereat. Each limiting support 18, 19 has a permanent slope inwardly and downwardly with respect to its associated jaw so as to permit the desired resilient flexing of the spring terminals.

A receptacle constructed in accordance with the above description for use with the specific examples of dimensions of flash-lamp also given above, namely, one having a base the total height of which is substantially three and nine-tenths millimeters in height, will require only a total depth of receptacle of five and four-tenths millimeters. Consequently, the receptacle requires very little space for accommodation in the flash device.

As a further modification of flash-lamp base (not shown) for a molded glass base formed from the flare in accord with the above disclosure, the protuberance 4 thereof may be longitudinally split or divided into two sections providing a valley or declivity between those sections. The in-leads could then be located between the sections within that declivity and would be even more fully protected than in the herein previously described construction.

We claim:

1. An electric lamp, more particularly a miniature photoflash lamp, with elongated tubular bulb and molded glass flare made as the lamp base, characterized in that at the transition of molded glass base and bulb there is formed an annular shoulder, said base having a protuberance integral therewith projecting outwardly from the end surface of the base in the direction of the lamp axis, and said protuberance having a non-circular crosssection providing side flanks extending in planes chordal to the tubular configuration of the lamp and establishing a declivity bounded at one side by said flanks and at another side by said end surface of the base, and current in-leads projecting from said base at a location contiguous to said flanks of the protuberance and entirely in said de-clivity for protection thereby from damage and disruption.

2. An electric lamp as claimed in claim 1, characterized in that the outer ends of the said current in-leads are bent sharply at their exit from said base and are carried along adjacent to the end surface of the base as short stumps entirely in said declivities.

3. In combination, an electric lamp as claimed in claim 1, a flash device therefor comprising a receptacle for receiving said base of said electric lamp, said receptacle having two semi-circular clamping jaws in an elongated 'hole of said flash device, elastic means holding said jaws together but permitting lateral sepanation of the jaws for introduction of said lamp base therebetween, said jaws when closed together providing an annular shoulder and cavity at their inner sides, two electric terminal springs at the under ends of said jaws directed toward each other, said springs having a gap between opposed ends thereof with the width of said gap at least as great as the width of said protuberance of the lamp base preventing the said protuberance from being pushed down below said opposed ends except when registering lengthwise with said gap, and the distance between the annular shoulder of the clamping jaws and said terminal springs corresponding nearly References Cited by the Examiner UNITED STATES PATENTS 2,415,902 2/1947 Noel 339 X 2,602,105 7/1952 VVelch et a1. 339228 2,715,216 8/1955 Howenstine 339255 X 2,891,231 6/1959 Gregson et a1. 33993 2,904,716 9/1959 Malrn et a1 339144 X FOREIGN PATENTS 657,270 9/ 1951 Great Britain.

EDWARD C. ALLEN, Primary Examiner.

W. DONALD MILLER, Examiner.

Claims (1)

1. AN ELECTRIC LAMP, MORE PARTICULARLY A MINIATURE PHOTOFLASH LAMP, WITH ELONGATED TUBULAR BULB AND MOLDED GLASS FLARE MADE AS THE LAMP BASE, CHARACTERIZED IN THAT AT THE TRANSITION OF MOLDED GLASS BASE, AND BULB THERE IS FORMED AN ANNULAR SHOULDER, SAID BASE HAVING A PORTUBERANCE INTEGRAL THEREWITH PROJECTING OUTWARDLY FROM THE END SURFACE OF THE BASE IN THE DIRECTION OF THE LAMP AXIS, AND SAID PROTUBERANCE HAVING A NON-CIRCULAR CROSSSECTION PROVIDING SIDE FLANKS EXTENDING IN PLANES CHORDAL TO THE TUBULAR CONFIGURATION OF THE LAMP AND ESTABLISHING A DECLIVITY BOUNDED AT ONE SIDE OF SAID FLANKS AND AT ANOTHER SIDE BY SAID END SURFACE OF THE BASE, AND CURRENT IN-LEADS PROJECTING FROM SAID BASE AT A LOCATION CONTIGUOUS TO SAID FLANKS OF THE PROTUBERANCE AND ENTIRELY IN SAID DECLIVITY FOR PROTECTION THEREBY FROM DAMAGE AND DISRUPTION.

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