US2183952A - Fuse lead construction for electric lamps - Google Patents

Description

Dec. 19, 1939. w, E, ANDERSON 2,183,952

FUSE LEAD CONSTRUCTION FOR ELECTRIC LAMPS Filed' May 15, 1938 2 sheets-sheet 1 d lNvENToR 45 fz K 7 WM5/amm v SYS i f V ATTO R N EY Dec. 19,l 1939. w. E. ANDERSON FUSE LEAD CONSTRUCTION FOR ELECTRIC LAMPS- Filed May l5, 1938 2 Sheets-Sheet 2 BYE1 n ATTORNY Patented Dec. '19, 19439 UNITED STATESv lPrxrlzN'r OFFICE 2,183,952 Y FUsE LEAD CONSTRUCTION Foa ELECTRIC LAMPS of Pennsylvania ApplicationvkMay 13, 1938, Serial No. 207,704

lI8 Claims.

This invention relates to electric 'lamps and more particularly to the construction of the fuse lead in high wattage lamps generally designated as bipost lamps. Y

During recent years it has become the practice to use fuses in certain classes of gas-filled lamps, for protection against destructive arcs upon failure of the lamp filament. The designs'commonly used previously either incorporate the fuse elebulb; fo'r example, in the stem-tube between the press and thebase, or internal as a part of the inner lead between the press and the filament. In both designs, however, the fuse has always been of the series type kwhere the lead is assembled by butt-welding the different parts together one after the other.

In bipost lamps, however, only the internal type of fuse is practicably applicable and since the lead wires must carry the entire mechanical load of the internal structure of the lamp, as well as the current, the series type of fuse introduces a weak link in the supporting structure which necessitates the use of expensive bracing parts to permit shipping the lampV and to withstand ordinary handling by the user. Likewise, the secondary arc produced by the operation of the fuse, when the lamp fails hot, tends to maintain itself between the ends of the adjacent larger parts of the lead wires, producing a comparatively large amount of hot metal and fuse cover material which scatters onto the bulb, resulting in consequent danger of breakage or explosion.

To overcome such objections, as well as avoid the necessity for Aexpensive butt-welding equipment, I have designed and demonstrated in lamps, a fuse lead construction which not only eliminates hazards from secondary arcs produced by the operation of the fuse itself, and provides a rigid structure to withstand shipping and handling; but is also much less expensive to manufacture.

It is, therefore, a principal object of my invention to providea gas-filled lamp, particularly of the bipost construction, comprising a rigid mount including a fuse, in order to avoid destructive arcs upon failure of the lamp, said mount p weld fuses and substitutes what might be termed a shunt fuse arrangement.

A still further object of my invention is the formation of a construction for lamps in which a fuse is so enclosed that arcing, upon failure of the lampandthe operation of the fuse, is minimized.

Other objects and advantages of the invention relating to the particular arrangement and con- .struction of the various parts will become apparent as the description proceeds.

. In the drawings:

Fig. 1 is a side elevational view of anl incandescent electric lamp of the bipost type embodyingv my invention.

Fig. 2 is an enlarged detail view of the fuse portion of the lamp of Fig. l, partly on line II-II .of Fig. 3, in the direction of the arrows.

Fig. 3 is an enlarged horizontal sectional View ,on the line III-III of Fig. 2, in the direction of the arrows.

Fig. 4 is an elevational view of the base and vleads of the lamp of Fig. 1, prior to insertion o the fuse.`

Fig. 5 is a partial elevational and partial vertical sectional view, as in Fig. 2, of a fuse for a lamp such as shown in Fig. 1, but illustrating a modification.

Fig. 6 is a view corresponding to Fig. 5, but showing another embodiment of my invention.

Fig. 'l is a fragmentary view of a portion of a bipost lamp corresponding generally to Fig. 1, but showing another embodiment of my invention. Y

Fig. 8 is an enlarged detailed view of the fuse lead, on the line VIII-VIIIv of Fig. 7, in the direction ofthe arrows.

Fig. 9 is an enlarged horizontal sectional View of said lead on the line IX-IX of Fig. 7, in the direction of the arrows.

Fig. 10 is an elevational view of a mount for another embodiment of my invention.

Fig. 11 is ay fragmentary elevational view on the line XI-EH of Fig. 10, in thedirection of the arrows.

Fig. 12 is an enlarged horizontal sectional view on the line XII-XII of Fig. 10, in the direction of the arrows.

' Referring to the drawings Ain detail, like parts4 being designated by like reference characters, and first considering the embodiment of my invention illustrated in Figs. 1 to 4, inclusive, there is shown a high-wattage lamp I4, of the medium bipost type, comprising an envelope I5 provided with a base I6, through which extend leading-in conductors I1 and |8 from terminal posts I9 and 2|.

The leading-in conductors I1 and I8 may be formed hollow to receive the conductors orsupport leads 22 and 23, the lower ends of which may be secured to said conductors I1 and I8 in 4any desired manner as'by crimping, asindicated at 24 and 25. The free or upper ends of the conductors 22 and 23 are, in the present embodlrnent, connected by wires 25 and 21, the outer ends of which are spot-Welded thereto, and the inner ends embedded in a glass or other insulating portion 28. Intermediate portions of the conductors 22 and 23 are likewise connected by wires 29 and `3|), the outer ends of which are embedded in a glass or other insulating portion 3|.

The filament 32, illustrated as of the coiled variety, is shown mounted between the conduc- , tors 22 and 23 and the insulators 28 and 3|, the

end' sections 20 of said filament being fitted over stifiening wires 40, and filament and wires welded or otherwise secured to the conductors 22 and 23, and the intermediate portions draped over hooks 33, 34, and 35, extending from the insulator 28 and hooks 38 and 31, extendingfrom the corresponding insulator 3|.

The insulators 28 and 3| also desirably carry wires or spuds which serve to support screens .or other means for Icollecting material vaporized from the filament, thereby minimizing the blackening of the bulb. 4For this purpose, the insulator 28 has spuds or support wires 38 and 39 which extend'laterally therefrom and to which.

from opposite sides of the insulator 28.'.

In the same way, a vaporized metal collecting screen 42 is desirably supported from the insulator 3| by spuds or wires 43 and 44 extending from the sides thereof and to which the screen is desirably spot-welded. The screen 42 is desirably V-shaped, like the corresponding screen illustrated in Fig. 11 and straddles the insulator 3|, .like the screen 4| thereabove. l When the envelope I5 has been filled with an inert gas and sealed, the lamp, as just described, is one of the high-wattage type, suitable for projectioni'or general lighting purposes. On account of carrying the necessaryvhigh current, failure of the filament is apt to result in a destructive arc between the adjacent ends of said filament. In order to avoid such an arcing,^I provide, in the present embodiment, a fuse 45 for the conductor 23. 'I'his fuse may be inserted by cutting the conductor 23 at the point 48, as shown in Fig. 4, as by means of shears 41, and then fitting an insulating lead-bracing tube 48 over vthe stub 49 of the conductor 23, as shown most clearly in Fig. 2.

After applying a glass or refractory bead 5| 'in the tube 48 above the free end of the stub 49, I thereafter insert the portion 52 of the conductor 23, which was cut off in the operation described in connection with Fig. 4, thereby rigidly uniting the adjacent ends of the portions 49 fractory like lava, being mentioned as an example, but, if desired, a glass tube may instead be satisfactorily used.

The fuse 45 of the present embodiment is formed as'a wire of nickel, or other suitable fuse material, of sufficientI cross section to carry the normal current without overheating, but which will fail by fusion upon the passage of excessive current which might flow upon the formation of an arc between the broken ends of the filament 32. The fuse 45 has most of its length enclosed in a tube 53, which may be of material corresponding with that of the tube 48, that is of Alsimag, glass, or the like, as desired. The free i ends of thewire 45 are desirably wound around the lead sections 49 and 52 and spot-welded thereto, as indicated at 54 and 55, thereby tightly holding said lead portions together and preventing their removal from the tube 48.

By positioning the fuse 45 parallel to the adjacent ends of the supporting lead sections 49' and 52,1 provide a structure which is sufiiciently rigid to withstand shipping and handling and is also much less expensive to manufacture. The close fitting refractory or'glass tube 48 provides rigidity for the lead 23, practically equivalent to that before cutting, and the fuse 45, of suitable size and material, ties the two parts of the main lead together, producing a rigid unit. With a close fitting refractory, tube 53, over the fuse, the action thereof is of the expulsion type;,that is, melting occurs inside, rather than outside, of the tube 53, due to said tube acting as a heat insulator, whereby upon melting, the metal vapors formed forcibly blow out the fuse sections at the ends of the cover tube, thereby quenching the arc formed by blowing it apart. Lamps manufactured with this type of fuse lead construction have shown it to be effective.

Referring now to the embodiment of my invention illustrated in Fig. 5, the fuse lead 23a is there shown interrupted and provided with a portion 45 reduced in section to correspond with that of the fuse 45 of the preceding embodiment. This section is desirably constructed of a piece 1 of nickel, or other suitable fuse material, of proper dimensions to provide the desired fuse characteristics, and has its ends secured to the adjacent ends of the heavy lead portions 49a and 52, as by welding, indicated at 54"v and 55.

The composite lead 23' then has applied thereover a refractory, glass, or other insulating tube 48, desirably closely fitting the heavy lead portions 49,and 52, and secured in place in any desired manner as bymeans of metal spuds 56 and 51, welded or otherwise secured to the lead sections 49I and 52 adjacent the ends of the tube 481. Inlthe present embodiment, the leadbracing tube 48n is shown provided with a hole 58 in its side, pointing away from the other lead (not shown), so that the air will be efficiently exhausted therefrom during manufacture of the lamp, and any vapors formed during melting of the fuse 45t are discharged away from said other lead.

Fig. `6 illustrates an embodiment of my invention correspondingk with' the fuse arrangement of Fig. 5, with modified features. Although the tube 48" preferably closely fits the lead sections 49b and 52", it need\ not fit closely, as the construction is here rigidifled by coils of wirev 59 and 60 which closely surround the ends of the lead-bracing tube 48b and have their outermost ends coiled around the lead sections 491 and 52b and welded or otherwise secured thereto, as indicated at 8l and 82. If the tube 48b loosely nts the sections 49b and 52, the aperture 88 may be omitted as the space around loose-fitting sections serves the same purpose. It will therefore be seen that this construction provides additional rigidity by securing the ends of the tube 48b to the main lead sections 49b and 52b by supplemental wire portions, in addition to the fitting of the lead sections in the tube itself.

Referring Inow to the embodiment of my invention illustrated in Figs. 7, 8, and 9, there is shown a fragmentary portion of a medium bipost lamp I4 comprising an envelopel5 provided with a base |8 through which extend leading-4 in conductors I1 and I8, from terminal posts I9 and 2I.

Extending from the conductors I1 and I8 are I support leads 22 and v23 connected by wires 29 and 30, the outer ends of which are spot-welded 'thereto and the inner ends embedded in a glass or other insulating portion 31. Although only the lower bracing device 29, 89, 8I is shown, it will be understood that the upper ends of the support leads are desirably connected by a bracing device similar to that shown in Fig. l and designated by the reference characters 26,21, 28. However, the filament may instead be supported as in the embodiment of Figs; 10, 11, and 12. Between the leads. 22, 23, and the bracing devices, or above or beyond the bracing device, is 'mounted an' incandescible filament desirably Y corresponding with that designated by the referencecharacter 32 in Fig. 1. As in Fig. l, screens, or only one, as shown and designated by the reference character 42, may be employed for collecting vaporized filamentary material during operation of the lamp.

In the present embodiment, the-lead 23 is formed in two sections: a lower section 49 and an upper section 52. The section 49 is secured to a metal connector plate 63 as by welding, and the section 52 is secured to a similar metal connecting plate 64, desirably in the same manner. These plates are 'separated by an insulating plate of mica or other suitable material 65, and held in` assembled relation, as illustrated, by bolts 66 and nuts 61 passing through associated insulating washers 68 and 89, and suitable aper'- tures in the associated plates 83, 84, and 85, in order` to rigidly connect the parts 49 and 52, forming the support lead 23, while insuring that said parts are insulated from one another.

As ingtheembodment of Figs. 1 to 4,k inclusive, I provide a bipass or parallel fuse device 1l r which, in the present embodiment, consists of terminal wires'12 and 13 tightly fittingin the ends of an insulating bracing tube 48 formed 0f refractory material or glass, like the tube 48 of the first embodiment. Between the enclosed end portions of the terminal wires 12 and 13 which form in effect extensions of the lead sections 52 and 49, extends a fuse wire 45, which may correspond with the fuse wire 45 ofthe first embodiment. The ends of the members 12 and 13 are desirably bent at right angles to the tube 48 and respectively secured to the upper .lead section 52 and the lowerlead section 49, as by spot-welding or inany desired manner, thereby further rigidifying the connection between the lead sections 49 and 52.

Referring now to the embodiment of my invention illustrated in Figs. 10, 11, and l2, there is disclosed a mount for a medium bipost lamp, said mount being provided with a base I8 and leading-in conductors I1.and l8 having terminal posts |9 and 20. Extending from the conductor I1, is a relatively thick or heavy 'support lead 22, to the upper end of which is secured an angular extension 14, as by spot-welding indicated at 15, and a short piece of wire or spud 18 carrying a glass insulator 11.

Extending from the leading-in conductor I8 is a relatively thin or light support lead 23 formed as a lower section 49, and an upper section 52, said sections having their adjacent ends tightly fitted in an insulating bracing tube 48. formed of glass or refractory material, and electrically connected by a .fuse wire 45 extending through said tube. In order to further brace the relatively light fused lead 23, the tube 48 is bound vto the relatively` heavy lead 22 by straps or wires 18 and 19, so that the whole structure is rigidified.

The upper section 52 of the lead 23 is desirably angular and connected to the angular lead extension 14 by wires 29 and 30, the outer ends of which are spot-welded thereto and the inner ends embedded in the glass insulator 11. Said insulator carries supporting hooks 8|, 82, 83, 84, and 85, over which a filament 32 is draped, the end sections 20 of said vfilament being fitted over rigidifying wires 40, and filament and wires connected, as by welding, to the ends of the lead extension 14 and the upper lead section 52, as indicated at 86 and 81. As in the preceding embodiments, an angular or V-shaped screen 42, for collecting vaporized iilamentary material, may be carried by the insulator 11 through supporting spuds 43 and 44.

In view of the foregoing disclosure, it will be seen that I have devised a novel fuse lead construction, especially adapted for high-wattage lamps of the bipost type, and avoiding weakening the mounts of such lamps by the inclusion of a fuse in a supporting lead thereof, while at the same time making it possible to manufacture such lamps economically and without serious manufacturing diiiiculties.

Although preferred embodiments of my .invenrtion have been disclosed, it will be understood' that other modifications may be made within the spirit and scope of the appended claims.

I claim:

l. An electric lamp comprising an envelope, a basefor said envelope, a pair of support leads extending from said base, a filament enclosed in said envelope and supported by said leads, insulating bracing means tightly fitting a portion of one of said leads, and a fuse associated with said bracing means.

2. An electric lamp comprising an envelope, a base for said envelope, a pair of support leads extending from said base, a filament enclosed in said envelope and supported by said leads, one of said leads being formed in twoparts, insulating bracing means connecting said parts', and a fuse blpassing said bracing means.

3. An electric lamp comprising an envelope, a base for said envelope, a pair of support leads extending from said base, a filament enclosed in said envelope and supportedvby said leads, one of said leads having an intermediate portion enclosed in aninsulating tube and separated by an insulating member therein, and a fuse exterior of said tube, the ends of said fuse being connected to said lead adjacent opposite ends of said tube..

4. An electric lamp comprising an envelope, a

base, a pair of support leads extending from said base, a filament supported by said leads, one of said leads `being in two segments, and the adja- 73 cent end portions of said segments tted in an insulating tube while separated by an insulating member, and an insulated fuse device parallel- .section to provide a fuse, land an insulating bracing tube tightly tting said lead and enclosing said fuse.

6. An electric lamp comprising an envelope, a base, a pairl of support leads extending from said base, a lament supported by said leads, one of said leads being formed in two sections connected by va fuse,v an insulating tube enclosing said fuse and receiving the adjacent ends of said sections, and a wire wound around each end portion of said tube and with its outer end secured to the lead section adjacent said tube.

7. An electric lamp comprising an envelope, a base, a pair of support leads extending from said base, a nlament supported by said leads, one of said leads being formed in two sections, the adjacent portions of said sections being secured to plates, separated by insulating means and connected together, so as to provide a rigid construction between said sections, while they are insulated from one another, and a fuse connecting said insulated lead portions.

8. An electric lamp comprising an envelope, a base, a pair of support leads extending from said base, a lament supported by said leads, one of said leads being relatively heavy and the other formed in two sections, the adjacent ends of which fit in an insulating tube and are connected by a fuse enclosed b y'said tube, and means binding said tube to the relatively heavy lead.

9. In a lamp, a fuse lead comprising a pair of conductors, the adjacent ends of which tightly nt an insulating bracingtube, and a fuse associated withsaid conductors to disrupt the passage` of an abnormal now of electric current therethrough.

`10. In a lamp, a fuse lead comprising a pair of conductors, the adjacent ends o1' which are tightly connected by an insulating bracing tube, and a fuse associated with said conductors to disrupt the passage of an abnormal ow of electric Acurrent therethrough.

11. In a lamp, a fuse lead comprising a-paixof conductors, the adjacent ends oi' which tightly t an insulating tube,l and are electrically insulated by a plug disposed therebetween, and a fuse associated with said conductors to disruptA the passageof an abnormal now ci electric current therethrough 12. In a lamp, a fuse lead for incandescent electric lamps comprising a pair of conductors, the adjacent ends of which are insulated from each other and enclosed in an insulating tube, and a fuse exterior of said tube, the ends of said fuse being connected to said conductors adjacent opposite ends of said tube to disrupt the passage of an abnormal ow of electric current therethrough.

13. In a lamp, a fuse lead for an incandescent electric lamp comprising a pair oi' conductor sections, adjacent portions of which are fitted in an insulating tube, while separated by an insulating member, a fuse wire paralleling said tube with its ends secured to said lead segments beyond said tube, and means enclosing said fuse.

14. In a lamp, `a fuse lead comprising supporting segments joined by afuse, said fuse being enclosed in an insulating tube, the end portions of which closely receive said segments for rigidifying the connection.

' 15. In a lamp, a fuse lead comprising an insulating tube, a fuse enclosed therein, supporting conductor sections, the adjacent ends of which Vit said tube and are connected by said fuse, and

wires closely wound around opposite ends of said `tube and with their outer ends secured to said sections.

16. In a lamp, a fuse lead comprising supporting conductor sections, the adjacent portions of said sections being secured to plates, insulating means separating 'said plates, means connecting said plates together so as to providea rigid union between said sections, while maintaining them insulated from one another, and a fuse connecting portions of said sections and by-passing said plates.

17. In a lamp, a fuse lead comprising a relatively `heavy supporting conductor, an insulating tube bound thereto and enclosing a fuse,l and

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