US3760217A

US3760217A - Single-ended halogen-cycle incandescent lamp with bridgeless mount assembly

Info

Publication number: US3760217A
Application number: US00283682A
Authority: US
Inventors: J Martin; J Gorecki
Original assignee: Westinghouse Electric Corp
Current assignee: Philips North America LLC
Priority date: 1972-08-25
Filing date: 1972-08-25
Publication date: 1973-09-18
Anticipated expiration: 1990-09-18

Abstract

The coiled filament of a tubular halogen-cycle type lamp is suspended within the envelope by a mount assembly which is so constructed that the lead wires are rigidly coupled to and electrically insulated from each other without the quartz bridge member customarily employed. Discoloration of the envelope in the region of the bridge member is inhibited and the lumen maintenance of the lamp is thus enhanced.

Description

United States Patent [1 1 Martin et al.

111 3,760,217 1451 Sept. 18, 1973 SINGLE-ENDED HALOGEN-CYCLE INCANDESCENT LAMP WITH BRIDGELESS MOUNT ASSEMBLY [75] Inventors: Jack Martin, Paramus; Joseph S.

Gorecki, West Caldwell, both of NJ.

[73] Assignee: Westinghouse Electric Corporation,

Pittsburgh, Pa.

221 Filed: Aug. 25, 1972 21 App]. No.: 283,682

[52] US. Cl 313/276, 313/222, 313/279, 313/286 [51] Int. Cl. H0lk 1/14, HOlk 1/18 [58] Field of Search 313/222, 271-276, 313/279, 285, 286, 289

[56] References Cited UNITED STATES PATENTS 1,842,167 1/1932 Hall 313/273 8/1947 Cartun ..3l3/279 8/1932 Cartun ..3l3/274 Primary Examiner-Rudolph V. Rolinec Assistant Examiner-Marvin Nussbaum Attorney-A. T. Stratton et a1.

[57] ABSTRACT The coiled filament of a tubular halogen-cycle type lamp is suspended within the envelope by a mount assembly which is so constructed that the lead wires are rigidly coupled to and electrically insulated from each other without the quartz bridge member customarily employed. Discoloration of the envelope in the region of the bridge member is inhibited and the lumen maintenance of the lamp is thus enhanced.

10 Claims, 6 Drawing Figures PATENTEDSEPB'QHI 3,760,217

SHEH 2 BF 2 FIGS.

SINGLE-ENDED HALOGEN-CYCLE INCANDESCENT LAMP WITH BRIDGELESS MOUNT ASSEMBLY CROSS-REFERENCE TO RELATED APPLICATION BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to electric incandesent lamps I and has particular reference to an improved filament mount structure for a quartz-halogen lamp.

2. Description of the Prior Art Halogen type incandescent lamps are well known in the art and are used in various industries and applications where a compact source of light or heat is required. A persistent problem in the manufacture of these lamps is that of connecting the ends of the lead wires to the coiled filament and maintaining the latter in centralized position within the tubular quartz envelope during the life of the lamp.

According to the teachings of the aforesaid copending application, the mount structure is simplified by bending the end of the long lead wire into a loop which nests within the top of the bulb and thus serves as an integral mount-positioning-and-bracing means. In one embodiment, a quartz bridge member joins the lead wires at the basal end of the lamp to rigidify the mount and serve as an anchorage point for a filament-support wire. In the other embodiment disclosed in the aforesaid copending application, the lower bridge member is omitted and the straight axially-extending portion of the long lead wire is encased in an insulating sleeve of quartz or the like to prevent it from contacting and short-circuiting the filament.

A quartz-halogen lamp having a bridge member that joins the long and sort lead wires together at the presssealed end of the lamp and has a fused hollow tip at the top of the bulb which is engaged by the inner end of the long lead wire is disclosed in U.S. Pat. No. 3,497,753 issued Feb. 24, 1970 to L. S. Huston, Jr. A tubular incandescent lamp having a long lead wire that is encased in a glass tube and held in centrally-disposed position within the envelope by bending the end of the long lead wire into a loop which nests within a tapered dome formed on the end of the envelope is disclosed in U.S. Pat. No. 3,300,675 issued Jan. 24, 1967 to Z. Deshaw. An incandescent lamp having a filament that is suspended in coaxial position within a tubular envelope by an auxiliary filament-support wire of spiral configuration is disclosed in U.S. Pat. No. 923,797 issued June 1, 1909 to R. McNeil]. A quartz-halogen lamp having a coiled-coil filament that is held in coaxial position within a tubular envelope by a pair of wire connectors having laterally-offset coil segments that are attached to the ends of the lead wires and respective legs of the filament is disclosed in U.S. Pat. No. 3,486,065 issued Dec. 23, 1969 to J. Martin.

While the aforementioned prior art mount structure held the filament in the desired axial position within the envelope and provided satisfactory electrical connections between the leads and filament, it has been found that the presence of the relatively massive bridge member of quartz or the like at the bottom of the bulb causes the latter to darken and become dicolored as the lamp burns. It is theorized that the bridge member acts as a sort of heat sink" which reduces theoperating temperature of the bulb wall in this region to a low enough value to permit vaporized tungsten from the filament to condense and remain on this part of the bulb. Another possibility is that the bridge member acts as a baffle which obstructs and impedes the circulation of the halogen gas through the bottom of the bulb and thus prevents it from gettering deposited tungsten particles and returning them back to the filament. Whatever the reason, the portion of the envelope adjacent the bridge tends to blacken during lamp life thus reducing the lumen maintenance and lamp efficiency.

It would accordingly be desirable to provide a rugged mount structure for a tubular halogen lamp which does not require a vitreous bridge member to rigidify the lead wires, or a filament support that requires such a bridge member to hold it in place. It would be especially desirable to provide a bridgeless mount structure for high-wattage halogen lamps of long length which thus have filament that requires some means of intermediate support.

SUMMARY OF THE INVENTION The foregoing objectives are achieved in accordance with the present invention by placing an insulating sleeve of quartz or the like over a medial portion of the long lead wire that is offset toward and extends along the inner wall of the envelope and by joining the end of the long lead to one end of the filament coil by coupling means which engages the hollow tip of the bulb so that the long lead and coupling means serves as a brace and centralizing structure for the filament. The end of the short lead wire is connected to the filament and attached to an insulated part of the long lead by a second coupling means thereby further strengthening the mount and providing a very rugged lamp.

In lamps having long singly-coiled filaments, intermediate support of the filament is achieved by means of wire loops that are attached directly to the filament and extend laterally toward and are seated against the insulated section of the long lead and surrounding portions of the bulb wall. Various forms of coupling means for joining the lead wires to each other and to the respective ends of the filament are disclosed.

The present invention thus provides a rugged and durable mount assembly which eliminates the need for bridge members and thus prevents premature bulb blackening.

BRIEF DESCRIPTION OF THE DRAWINGS A better understanding of the invention will be obtained from the exemplary embodiments shown in the accompaying drawings, wherein:

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1 there is shown an 800 watt single-ended incandescent lamp of the halogen-cycle type which embodies one form of the invention and comprises the usual tubular envelope 12 of quartz (orother suitable high melting point material) that is terminated by a hollow fused tip 13 and is hermetically closed at its opposite end by a press seal 14 and contains an elongated singly-coiled filament 15 of tungsten wire. The envelope 12 in this particular embodiment is of the T 2 A type (5/16 inch or 7.9 millimeters OD) and contains an inert gas such as a mixture of argon and nitrogen that is dosed with a suitable halogen such as iodine or bromine. The filament 15 is suspended in coaxial position within the envelope 12 by a mount assembly which includes a short lead 16 and a long lead 17 that are embedded and anchored in the press seal 14 and connected by the usual ribbon conductors and outer leadsto the terminals of a base 18 that is cemented to the press seal.

As will be noted in FIG. 1 and shown .more particu-' larly in FIG. 2, the filament coil 15 is maintained in the desired coaxial location within the envelope 12 by offsetting the central portion of the long lead 17 so that it is disposed adjacent and extends along the inner wall of the envelope, encasing this lead portion in a sleeve 22 of quartz (or other material such as alumina or a suitable ceramic), and bending the free end of the long lead to provide a transversely-extending arm 19 which is terminated by an axially-extending coiled segment 20 that is dimensioned to threadably fit into and engage the end of the filament coil 15. A short spud wire 21 is partly inserted into the coiled segment 20 of the long lead 17 and securely fastened in such position by hot clamping thereby electrically and mechanically coupling the members and permitting the end of the spud wire 21 to enter and engage the envelope tip 13.

The short lead wire 16 is electrically connected to the other end of the filament 15 and mechanically attached to an insulated part of the long lead 17 by a connector 23 consisting of rigid wire that is wound into two laterally-offset

coiled segments

24 and 25 that are joined by a transverse arm portion 26. The coiled segment 24 is of such size that it threadably engages and is interlocked with the end of the helical filament 15 and snugly receives the end of the short lead 16 to which it is secured by welding. The length of the arm portion 26 is such that the other coiled segment 25 can be slipped over the insulating sleeve 22 (when the mount is being assembled) and thus maintain that end of the filament 15 in the desired coaxial alignment. The connector 23 effects a snug fit with the sleeve 22 and is locked in place thereon by fusing a short collar 28 of quartz or the like to the sleeve 22 (after the filament 15 is pulled taut) so that the end of the collar 28 is seated against the coiled segment and acts as a stop. This arrangement permits a wider tolerance for the inside diameter of the coiled segment 25 and automatically positions the connector 23 on the long lead 17 during mount assembly.

As will be noted in FIG. 2, the singly-coiled filament 15 is devoid of any depending legs and consists of a coil barrel of cylindrical configuration. The filament 15 (as illustrated in FIG. 1) is supported at a plurality of spaced points along its length by wire spirals 30 that are attached directly to the turns of the filament l5 and extend laterally toward and nestingly engage the insulating sleeve 22 and the curved inner wall of the envelope 12.

In the alternative lamp embodiment 10a shown in FIG. 3, a'slightly modified filament mount assembly is employed. Coupling of the components at the upper end of the mount according tothis embodiment is achieved by terminating the transverse arm segment 19a of the long lead 17a by a coiled segment 20a that extend axially toward the bulb tip 13a rather than toward the proximate end of the filament 15a. The coiled segment 20a and spud wire 21a are fastened to each other and to the end of the filament 15a by a coil insert 27 that threadably engages and is interlocked with the end of the filament barrel and snugly receives and is hot clamped to the spud wire 21a. The other end of the coil insert 27 is threaded into and interlocked with the coiled segment 20a of the lead wire so that the protruding end of the spud wire 21a enters and engages the tip 13a of the envelope 12a when the mount assembly is inserted into the envelope prior to the press-sealing operation. Of course, as will be recognized by those skilled in the art, at this stage of lamp manufacture the fused tip 13a has not yet been formed and the end of the spud wire 21a is positioned within the depending exhause tubulation which is subsequently melted and severed to form the fuse tip 13a, after the envelope 12a has been evacuated and dosed with fill gas and halogen.

The lower end of the filament 15a is coupled to the short lead wire 16a by providing a pair of

coiled segments

31 and 32 on the end of the short lead, which segments are joined by an opened turn 33 (shown more clearly in FIG. 4). The end of the filament 15a is threaded over and interlocked with the coiled segment 32 and a modified connector 23a is employed to secure the short lead 16a to an insulated part of the long lead 17a. The connector 23a is generally U-shaped and has a longitudinally-disposed coiled segment 25a and a longitudinal-depending straight leg segment 34 that are joined by a transverse arm segment 35 which is of such length that it permits the leg segment 34 to be inserted through the opened turn 33 and into coiled segment 31 of the short lead 16a. As before, coiled segment 25a is dimensioned to effect a snug fit with the tubular insulator 220.

In FIG. 5 there is shown a 250 watt halogen-cycle lamp 10b that has a coiled-coil filament 15b which is much shorter and thus does not require any auxiliary filament-support means. The envelope 12b is of the T-4 type one-half inch or 12.7 millimeters OD) and is closed by a fused hollow tip 13b at one end and by a press seal 14b at its opposite end in the customary fashion. In accordance with this embodiment, the short lead 16b is attached directly to an insulated part of the long lead 17b by bending the end of the short lead toward the long lead and forming the end of the short lead into a longitudinal-extending coiled segment 36 that encircles and grips the insulator sleeve 22b and is terminated by a transverse arm segment 37 and a downwardly-extending leg segment 38. The conjoined end of the filament 15b is formed with an open turn 39 in the primary winding so that a short axially-extending coil section 40 is provided at that end of the filament. The leg segment 38 is inserted through the open turn 39 and into the coiled section 40. The upper end of the filament 15b is coupeld to an axially-extending coiled segment 20b on the long lead wire 17b by bending one end of the spud wire 21b into a partial turn which is threaded into the primary winding of the coiled-coil filament to form a button hook connection, and then slipping the coiled segment 20b over the straight portion of the spud wire 21b and hot clamping them together.

Alternatively, the upper end of the coiled-coil filament 15b can also be provided with an opened primary turn and a depending coil section and the end of the long lead 17b can be bent into an L-shaped hook that is inserted into the opened turn and through the coiled section of the filament to provide the same basic type of connection as that employed at the lower end of the filament.

In the alternative 250 watt lamp embodiment c shown in FIG. 6, a modified coupling arrangement is used to fasten the short lead wire 160 to the coiled-coil filament c and the insulated portion of the long lead wire 17c. As shown, the end 41 of the short lead 160 is bent into a partial turn which is screwed into the end turn of the filament 15c and is welded to a coiled leg segment 42 of a connector 23c. The latter is U-shaped and has another longitudinally-extending coiled leg segment 43 that is slipped over and snugly on the insulator sleeve 22c which encloses the offset portion of the long lead wire 17c. The coiled leg segments of the connector 23c are joined by a transverse arm segment 44, as shown.

The other end of the filament 15c is coupled to the end of the long lead wire 17c in the same manner as in lamp embodiment 10b so that the end of the spud wire 21c engages the tip 13c of envelope 12c.

We claim as our invention:

1. A single-ended halogen-cycle incandescent lamp comprising:

a tubular envelope of vitreous light-transmitting material that contains a halogen additive and has a press seal at one end and a closed centrallydisposed fused hollow tip at its opposite end,

a coiled tungsten filament of elongated configuration suspended in longitudinal position within said en- I velope, and

a bridgeless mount assembly holding said filament in such suspended position comprising (a) a pair of rigid lead wires of unequal length that are embedded in said press seal and extend into said envelope, (b) means electrically insulating amedial portion of the long lead wire, (c) first coupling means fastening the end of the. long lead wire to one end of said filament and engaging the hollow tip of said envelope, and (d) second coupling means fastening the short lead wire to the other end of said filament and to an insulated part of the long lead wire, said long lead wire being offset toward and extending along the wall of said envelope and being terminated by a transverse arm segment that extends toward the filament and, in turn, is terminated by a longitudinally-disposed coiled segment that is in substantially coaxial alignment with the filament and constitutes part of said first coupling means. 2. The halogen incandescent lamp of claim 1 wherein said first coupling means includes a spud wire that extends into the tip of the envelope and into the coiled end segment of the long lead wire and associated end of the filament.

non-conductive material that encloses the offset medial portion of the long lead wire which extends along the 5 wall of said envelope.

4. The halogen incandescent lamp of claim 3 wherein a wire loop is anchored to a medial part of said coiled filament and extends transversely therefrom toward said insulating sleeve and the wall of said envelope and thereby constitute auxiliary support means for said filament.

5. The halogen incandescent lamp of claim 3 wherein said second coupling means inlcudes a wire connector component that extends transversely from the associated end of said filament to the long lead wire and is .terminated by a coiled segment that encircles and grips said insulating sleeve.

6. The halogen incandescent lamp of claim 5 wherein;

the coiled end segment of said long lead wire extends into and is threadably interlocked with the associated end of the filament, a spud wire extends from the tip of said envelope into the coiled end segment of said log lead wire, and

the end of said wire connector component that is fastened to the other end of said filament comprises a coiled segment that extends into and is threadably interlocked with the filament.

7. The halogen incandescent. lamp of claim 5 wherein; H

the coiled end segment of saidlong lead wire is axially spaced from the associate-d end of the filament and is of substantially the same inner diameter as the coiled filament,

a coiled connector component extends into and is threadably interlocked with the adjacent portions of the coiled end segment of said long lead wire and associated end of the filament, and

a spud wire extends from the tip of said envelope into the said coiled connector component. 8. The halogen incandescent lamp of claim 5 wherien;

the end of the short lead wire is also terminated by a longitudinally-disposed coiled segment that (a) extends into and is threadably interlocked with the associated end of said filament, and (b) is joined to a second coiled segment by an opened turn,

said wire connector component has a depending uncoiled leg segment that extends through the opened turn and into the said second coiled segment of the short lead wire that protrudes from the associated end of said filament.

9. The halogen incandescent lamp of claim 3 wherein;

said filament is of the coiiled-coil type, and

the short lead wire is (a) offset toward the long lead wire, (b) has a medial coiled segment that encircles and grips said insulating sleeve, and (c) is terminated by leg segment that is welded to a coiled section of the filament which is joined to the filament barrel by an opened primary turn.

10. The halogen incandescent lamp of claim 3 wherein;

said filament is of the coiled-coil type, and

said second coupling means inlcudes a generally U- shaped wire connector that is terminated at each end by a longitudinally-disposed coiled leg segment, one of which encirclesand grips said insulating sleeve and the other of which encircles and is secured to the end of the short lead wire.

Claims

1. A single-ended halogen-cycle incandescent lamp comprising: a tubular envelope of vitreous light-transmitting material that contains a halogen additive and has a press seal at one end and a closed centrally-disposed fused hollow tip at its opposite end, a coiled tungsten filament of elongated configuration suspended in longitudinal position within said envelope, and a bridgeless mount assembly holding said filament in such suspended position comprising (a) a pair of rigid lead wires of unequal length that are embedded in said press seal and extend into said envelope, (b) means electrically insulating a medial portion of the long lead wire, (c) first coupling means fastening the end of the long lead wire to one end of said filament and engaging the hollow tip of said envelope, and (d) second coupling means fastening the short lead wire to the other end of said filament and to an insulated part of the long lead wire, said long lead wire being offset toward and extending along the wall of said envelope and being terminated by a transverse arm segment that extends toward the filament and, in turn, is terminated by a longitudinally-disposed coiled segment that is in substantially coaxial alignment with the filament and constitutes part of said first coupling means.

2. The halogen incandescent lamp of claim 1 wherein said first coupling means includes a spud wire that extends into the tip of the envelope and into the coiled end segment of the long lead wire and associated end of the filament.

3. The halogen incandescent lamp of claim 1 wherein said insulating means comprises a sleeve of electrically non-conductive material that encloses the offset medial portion of the long lead wire which extends along the wall of said envelope.

5. The halogen incandescent lamp of claim 3 wherein said second coupling means inlcudes a wire connector component that extends transversely from the associated end of said filament to the long lead wire and is terminated by a coiled segment that encircles and grips said insulating sleeve.

6. The halogen incandescent lamp of claim 5 wherein; the coiled end segment of said long lead wire extends into and is threadably interlocked with the associated end of the filament, a spud wire extends from the tip of said envelope into the coiled end segment of said log lead wire, and the end of said wire connector component that is fastened to the other end of said filament comprises a coiled segment that extends into and is threadably interlocked with the filament.

7. The halogen incandescent lamp of claim 5 wherein; the coiled end segment of said long lead wire is axially spaced from the associated end of the filament and is of substantially the same inner diameter as the coiled filament, a coiled connector component extends into and is threadably interlocked with the adjacent portions of the coiled end segment of said long lead wire and associated end of the filament, and a spud wire extends from the tip of saiD envelope into the said coiled connector component.

8. The halogen incandescent lamp of claim 5 wherien; the end of the short lead wire is also terminated by a longitudinally-disposed coiled segment that (a) extends into and is threadably interlocked with the associated end of said filament, and (b) is joined to a second coiled segment by an opened turn, said wire connector component has a depending uncoiled leg segment that extends through the opened turn and into the said second coiled segment of the short lead wire that protrudes from the associated end of said filament.

9. The halogen incandescent lamp of claim 3 wherein; said filament is of the coiiled-coil type, and the short lead wire is (a) offset toward the long lead wire, (b) has a medial coiled segment that encircles and grips said insulating sleeve, and (c) is terminated by leg segment that is welded to a coiled section of the filament which is joined to the filament barrel by an opened primary turn.

10. The halogen incandescent lamp of claim 3 wherein; said filament is of the coiled-coil type, and said second coupling means inlcudes a generally U-shaped wire connector that is terminated at each end by a longitudinally-disposed coiled leg segment, one of which encircles and grips said insulating sleeve and the other of which encircles and is secured to the end of the short lead wire.