US 2403137 A
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Description (OCR text may contain errors)
ly R. F. STRICKLAND 2,403,137
BASING' FOR ELECTRIC LAMPS AND LIKE Filed July 1, 1943 Inveni-or. Ro aL E S+r-icktand,
Patented July 2, 1946 BASING FOR ELECTRIC LAMPS AND THELIKE 1i Royal F. Strickland, Clevelaiid Heiglits,
signor to General ration of New Yor kElectrid company,
a corpo? Q Application July 1, 1943, Serial Nd 492,988 f This invention relates to basing the bulbs or envelopes of electrical various kinds, which at present generally have vitreous envelopes. The
invention aims at simdrawing. V
In the forms of construction here illustrated, the main attachment of the base to the lamp bulb is made by direct mechanical engagement of a base shell with a lamp bulb, by screwing the shell directly on the bulb end or neck, without any need of basing cement. This makes the construction very advantageous for bases of Edison or screw typesthough it is also applicable to other types of bases having shells that are internally screw threaded, even though they might be externally plain and unthreaded. With tionis combined an adhesive attachment of the base contact shell to the bulb neck-,. by a film' of suitable adhesive applied between their inter-engaging surfaces, to secure the contact shell against unscrewing from the neck when the device is unscrewed from a socket in external screw engagement with the shell-.- Since the screw shell can be screwed on and finally jammed on the bulb neck with more force than need ever be used in screwing the lampinto a socket, and since the' torque required to unscrew a lamp'from a socket is much less than that used in screwing the lamp into the socket, the unscrewing torque to be taken by the cement is quite moderate, and well within the holding power of bulb threadsmay be of incomplete or mutilated character, although simple, ordinary threads are at present generally preferred. The electrical connections of the lamp leads to the base conthe screw conneca good cement. The
' andits threaded portion Ifl do not 56- essentiaL- l .of course, is-;done before tacts are made without solder, by mere mechanigcal clamping. a 1 r In one for-moi construction, the side lead to the screw shell contact is wedged or crowded bee tween the outside of the bulb neck and the inside of the shell, and thus held clamped into electrical con-tact with the shell. To reduce theresulting eccentric pressure and stress afiecting the bulb neck, the neck may have a longitudinal depression or groove across its accommodate the side lead; groovingacross the threads In the drawing, Fig. 1' is a sidevie'w of a. lamp bulb suitable for the purposes of the invention; Fig; 2 is a-similar but tilted view of a base for this lamp, partof the screwshell being broken out to reveal its interior; and Fig; 3 is a fragmentary tilted-view, partly sectional, showingthe application ot'the base to the lamp.
Fi g 4- is a fragmentary side view illustrating a modified construction, the base being shown in section'and the lamp bulb neck to which it is applied inelevation Fig, 5is a similar view illustrating another modification; and Fig. 6' is ari ex'.'- ploded tilted view of the parts of the base shown inFig 5; I 1
Fig.- 1' shows arr-ordinary type of electric lamp L whose bulb end or neck I0 is externally screw threaded at ll in a manner suitable for the purposes of 7 my invention.
V v As illustrated, the end of the bulb neck I'llis closed; and the construction is of an ordinary type comprising a stem flare l 2 tused a-ndsealed to'the-neck at l 3-and itself closed at its'inn'er end by a pressed seal- 4 throughwhichv are sealed-- the current lead wires l5, Hi to the electrictranslation means of the device,- such as an incandescent coiled coil tungsten filament I 1 suitably mounted in thebulb l0. An exhaust tube I8 isshown as opening through the seal or suitable or preferredmanner: for example, they may be iormedjust-after sealingin. by placing the bulb neck (while still hot. and soft) in a mold of suitable internal conformation and blowing airinto the bulb through the' tube l8. This,
7 the bulb is exhaustprocessed and tipped 01f. j Y
As thus farv described; the bulb or; envelope L differ greatly from what isdisclosed-in such U. S} patents as Nc. 1,650,289 to McGinley and N0. 2,066,317 to 7 Blake and Geiger-though the described. method of forming the threaded part II is difierent from those set forth in these patents.
Fig. 2 shows one form of lamp base B that is 5 suitable for the purposes of my1invention,'be-r ing an Edison screw base comprising a sheet metal screw contact shell or skirt 20 with "an insulative body, web, or button 2i (such as glass)v As in present commercial 1 at one end thereof.
its other end is flanged and rounded inward end-body or insulator 21 is shown as of rrustm: conical conformation where it projects from the corresponding end of the screw-shell 20. On the outer side of the insulative body 2i is exposed an end or center contact 25, here shown as a sheet I'metal' disc. forming the enlarged outer head or j flange of a rivet-like center contact eyelet whose 25 j hollow'shank or sleeve portion26 is molded into the body 2| and is open through it, just as in ordinary commercial Edison bases.
Unlike the centercontactsof ordinary commercial'bases; the contact disc or flange 25 has 30 a" notch or I periphery to o slit 21 extending inward from i atone (cou terclockwise) side'of the slit 21 is raised or turned up at 28, above that at the other side of the slit, over an angular width of a few; degrees v(counterclockwise) around the disc. The'slitted feature of the center contact 25, and its use as hereinafter described in electrically connecting the center lead It to this coni 4 tact-these correspond essentiallyto what is disclosed in the application ofJohn J. Malloy, Serial No. 447.818, filed June20, 1942, now Patent n asscgssc, assigned to the assignee of this e 'plicatio n. 7 a V, 7 V
Before applying the base .3 to .he lamp L, thelamp lead which is to be the side lead to thescrew shell is bent outward across the sealed neck end 13 and back lengthwise of the neck"), to extend crosswise of the screw threads I 50 H and even somewhat beyond them. The lamp lead l6 which is to be the center lead to the end contact may beleft extending straight outward from the neck end l3. As shown in Fig. 1, the bulb neck or groove extending. fromthe beginning of the threads: H outside the. seal l3 across the threaded zone and even slightly beyond, to accommodate the side lead l5 when retroverted as above mentioned. groove appear best in Fig. 3, which shows the base B installed on the lamp bulb L. While the groove 30 is not here shown as of uniform depth below theundulatory general surface of the glass across the threaded area, its bottom, neverthe- 65 less, has undulations corresponding with those of the general surface, though of much smaller amplitude: i e., the groove 30 cuts almost if not quite through the full depth of the protuberant thread ridges, but is only slightly sunk into f the bottoms of the thread valleys at 3|; If
' the groove depth at His less than the diameter of the lead wire l5, the wire would obviously be crowded against the-internal'ridgesof the'screw r shell-thread ridges. 0 tion of the wire l5 in the groove 30 resembles thatof a beam continuous across a series of supjports and loaded at the center-of each span with even into the flaring endof the sleeve 26, and the margin of the sheet metal The essential features of this 3| exceeding the wire diameter, as shown in Fig. 3, the wire is nevertheless clamped, effectively,
against the shell 20 into electrical contact there- 'with, being touched and resiliently flexed slightly by the internal shell thread ridges, since at the glass-thread ridges the groove bottom lies further from the common axis of bulb neck and screw shell than do the crests of the internal In other words, the condioconcentrated loads not exceeding its elastic limit.
x. Thus the groove 31] difiers very essentially from thesuperflcially similar groove in the abovecited McG'inley patent, which is everywhere so '1" deepthatiMcGinleys side-lead lies sheltered in its bottom, without being in any wise forced into contact with the screw shell-to which; indeed, it
is electrically connected by solder at the edge of theshell. 7 E a c a 7 When the'base B is to be put on the lamp bulb L, afew drops'of adhesive of any suitable character "are first applied to the inside of the screw shell 20, as indicated by the shaded area 333m Fig. 2, or to the bulb neck portion l2 as indicated by the shaded area 34inF'1g. 1', or both. Then the center lead us is threaded through the end a contact hole orbore'in the eyeletshank 26 and the base B is screwed on the bulb neck I 0 while the side lead I5 is held in place in the neck groove 30 by its-end'that projects beyond the screw threads II as shown in Fig.1. Screwing on the base 13 in this manner'not only squeezes and spreads the adhesive 33 or 34 into a thin film between the threaded surfaces of the-parts H and 20, but also forces and clamps the lead wire l5 into electri'cal'contact with the insideof the. screw shell 20, Any adhesive on the shell '20 wherethe wire it bears against it is scraped away by the wire-or squeezed out from between the parts by the pressure-insuringgoodcontact. The free end of the wire 15 may then be out off flush with the shell edge 23. After the. base B 5 has been screwed home firm and tight on the bulb neckso tight, even, that it'can scarcely be unscrewed by handthe lead wire: 16 1s" bent'aside In has a longitudinal channel 5 yond the disc edge an p ng theiwireen'd in under the disce-ethe wire I6 is clamped still more .flrmly and secured against outward displacement. This final condition ofthe parts is shownin Fig. 3. When the fllm of adhesive between the shell 20 and the neck portion l2 has dried or hardened, it secures the shell against unscrewing from the neck when the lamp L is unscrewed orbacked out of the screw shell contact of a socket (not shown) into which it has been screwed in service.
The adhesive applied to the screw shell 'at'33 or to the bulb neck at 34 may beofany kind that will form a thin filmand will when dry, hard, or curedf bond the parts together against'unscrewing from one anotherin service; For'example, it'may be of a varnish type, compriS p a base of rubber, gum, resin, or asphaltum, etc.,
in a suitable volatile solvent such as shellac in alcohol or itmaybe of a water-'glasstypd-conshell threads; but'even with the groove depth at (5" siumf or zirconiumdis'solvedin water; Slowsettingeums ompl s c are al csuita l s eit matters very little: qwilo ta es the a hesive to. harden after ;the;-:sc13ew shelluis screwed on thebulbneck. g ,2
. The construction illustrated in. Fig. 4; differs from that of =Figs.:13'both as regards the connections ,of the leads l5, l,6jto the shell and center contacts and also as regards the attachment of the insulative base end 2Ia to the screw shell Mat-corresponding in-this latter respect substantially to what is disclosed in U. S. Patent 2,210,525 to Carl A. Brown and Clarence E. Hahn. Accordingly, the insulative base end 2| a is shown as a bevelled button (preferably glasslthat is cen--v trally apertured at 26a for passage of the center lead-wire l6 and is peripherally engaged and seated in and against an annular seat 35 formed at the outer. end of the shell by doubling the sheet metal of the shell back thereinto and flanging its extreme margin inward. The button 2la may be peripherally gripped and secured in the seat 35 by spinning in the outer annular corner of the seat on the bevelledbutton edge, as shown at 36. The side lead 15 is not retroverted as in Figs. 1 and 3, but extends from the neck end l3 to the shell-end seat 35, where it bends outward under the button 2la and then across its outer edge as shown, being thus held clamped into electrical contact with this shell portion 35 by the grip of the annular corner or margin 36 of the seat 35 on the button. The end contact a is shown as a mere cap whose annular wall (which may be crimped as shown) is wedged fast and thus clamped in a corresponding annular groove 31 in the outer side of the insulator 2la concentric with the lead hole 26a, as shown in U. S. Patents 2,047,043, granted to me July '7,
1936, and 2,066,317, granted to Blake and Geiger January 5, 1937-the latter already hereinbefore mentioned. The center lead I6 is shown as secured and electricallyconnected to the end contact 25a by being clamped between the insulator 2la and the interior surfaces of the contact cap 25a as in the two patents last cited. The side lead l5 not being retroverted between the screw shell 20a and the bulb neck portion I 2, the groove 30 of Figs. 1 and 3 is entirely superfluous, and
is omitted in Fig. 4.
The construction illustrated in Fig. 5 differsv from that of Fig. 4 in having its insulative base end or button 2 lb secured in the screw shell seat 35b by snap action; in having its center contact 25b also snap-fastened to the insulator 2 lb; and in having the leads I5, I 6 clamped into electrical contact with the shell and center contacts 20b, 25b by the elastic action of the snap fastenings all as shown in U. S. application Serial No. 456,351, filed August 27, 1942, by Paul O. Cartun, now Patent No. 2,336,529.
As in Figs. 11 and 12 of the said Cartunapplication, the plain annular wall of the insulator seat 35b is interrupted by the punching out of a few isolated spring fingers 31 (three being shown) whose free lower ends are bent inward to snap into corresponding bevel-shouldered notches 38 in the insulator 2lb when the latter is put in place and pushed home in the seat 35b. As in Figs. 1, 2, and 3 of said application, the center contact 25b consists of a disc-like head with a hollow sh'ank .iwhichlre shew iwithae mrne t eve ed heu ers -at, their freeglower ends, for snapping-outward :be- .h n h .,-s 0 er o t .tqp nsfi wh n h contact is. pushed home; into the opening. The contact 25b may :be formed, of sheet-metal by a die-pressingand drawing operation, the margin of its head being formedbydoubling under the sheet metal as. shown in Fig. 5.
The connection of the side lead l5 to the screw shell 201) may be made by simply passing the lead through the shell 2% when the base B is put on the bulb neck, and then bending the lead I 5 aside so that it will be clamped between the shell portion 35b and the insulator'2lb, when thelatter is snapped into place, by the elastic snap action of the resilient fingers 31. Afterward, the wire l5 may be cut off about as shown at 42. The connection of the center lead Hi to the contact 25 may be made in a similar way, by passing this lead through the insulator opening 39 when the base B is put on the bulb neck and bending the lead aside, so that it willbe clamped between the contact 251) and the flat outer surface of the insulator Zlb when contact is snapped into place, by the elastic snap action of the spring fingers 40. Afterward, the wire [6 may be cut off as indicated at 43.
It will be appreciated that the constructions In Figs. 4, 5, and 6, various parts and features are marked with the same reference characters as those corresponding in earlier figures, in order to'dispense with repetitive description-at distinctive letter being added where such distinction seems desirable. 1
What I claim as new and desire to secure by Letters Patent of the United States is:
1, The combination with a vitreous lamp bulb or the like having an externally screw threaded neck, with current leads issuing therefrom, and also having across the screw threads a groove with its bottom undulated in correspondence with the undulations of the screw threaded neck surface, but to a less depth, of a metal screw shell contact screwed on said threaded neck, with an of said current leads extending along in said neck groove resiliently flexed between the undulations of the groove bottom and the internal undulations of said screw shell, and thus held in electrical contact with the latter; a base end insulator closing the end of said shell; and an end contact mounted on said insulator having an other of said current leads mechanically clamped into electrical contact therewith.
2. The combination with a vitreous lamp bulb or the like having an externally screw threaded neck, with current leads issuing therefrom, and also having across the screw threads a groove with its bottom undulated in correspondence with the undulations of the screw threaded neck surface, but to a less depth, of a meta1 screw shell ca ister serew an said threadeil'iieck, 'wi'ni an adhesive 'film'between said neck 'gn d' shell securing the'lati'eragainst unscrewing frcm'thene'ck when th'e de'vice is unscrewed from alsocket in' external screw engagement with said shell, one
'of said current leads extending aldng'insalid neck groove resiliently flexedbetween the undulations sulator closing the end of said shell; and an end contact on said inslilator having another of said "cirrrenl; leacls' electrically'connected thereto.
V ROYAL STRICKLAND.