US3094640A - Harness for supporting high pressure arc discharge tube within outer envelope, and lamp formed thereby - Google Patents

Description

June 18, 1963 D HARNESS FOR SUPPORTI N OUTER ENVELOPE, AND

FORMED THEREBY TUBE WITHI LAMP Filed Dec. 19, 1960 ARGE . S. GUSTIN NG HIGH PRESSURE ARC DISCH 2 Sheets-Sheet 1 DANIEL S. GUSTIN INVENTOR.

A TORNEY June 18, 1963 D. s. GUSTIN 3,094,640

HARNESS FOR SUPPORTING HIGH PRESSURE ARC DISCHARGE TUBE WITHIN OUTER ENVELOPE, AND LAMP FORMED THEREBY Filed Dec. 19, 1960 2 Sheets-Sheet 2 DANIEL S. GUSTIN INVENTOR.

AT ORNEY United States Patent HARNESS FOR SUPPORTING HIGH PRESSURE ARC DISCHARGE TUBE WITHIN OUTER ENVE- LOPE, AND LAMP FORMED THEREBY Daniel S. Gustin, Londonderry, N .H., assignor to Sylvania Electric Products Inc., a corporation of Delaware Filed Dec. 19, 1960, Ser. No. 76,799 12 Claims. (Cl. 313-25) This invention relates to high-pressure, electric discharge devices and more particularly to an improved arc tube support generally called a harness.

High pressure electric discharge lamps are well known and are described, for example, in United States Patent 2,901,647 to M. J. Thomas et al. Such lamps comprise an inner arc tube mounted in a surrounding, light-transmitting, outer envelope by an intermediate supporting harness. The outer envelope may be left clear or may be coated with phosphor material as desired.

In the manufacture of such lampsit has been found that one of the more troublesome steps is the sub-assembly operation of constructing the harness which holds the arc tube in the outer envelope. This harness generally comprises a large number of structurally stable bent wires and metal supporting brackets which are spot welded together in separate steps. Each spot weld affords an opportunity for imperfection in lamp construction and accordingly it is desirable to eliminate such wires, brackets, and spot welds. Furthermore, it is desirable to prepare as much as practical of the construction in a unitary stamped-out design.

For such reasons, attempts have been made to use a single-wire arc tube support, wherein a metal wire is suitably bent and shaped to support the arc tube in the bulbous envelope. Such constructions, however, are not entirely acceptable since there is not significant diminution of the number of spot welds required to fabricate the harness nor does it produce a structurally stable device.

Another proposed harness comprises a pair of similar stamped-out support members, which are spot welded in numerous places after the arc tube has been positioned between suitably shaped cross arms. This design was not entirely satisfactory since the number of spot welds is not appreciably reduced. Furthermore, it makes no provision for accommodating small variations in lengths from tube to tube.

When prefabricating a lamp using the unitary harness as proposed in this invention there are no spot welds utilized to prepare the harness itself; only a few are necessary for the attachment of the various electrical contacts. Furthermore, the harness is shaped to each in dividual arc tube and small difierences in the length of each tube may be compensated without any difficulty.

Accordingly, an object of the present invention is the fabrication of a structurally stable, unitary, stamped-out arc tube harness requiring a minimum number of welds.

An advantage of this invention is that the number of spot welds necessary has been reduced from twenty-two to six, thus reducing the manual labor required to fabricate the arc tube supports.

Another advantage of this invention is the ease and cheapness of mounting the arc tube and preparing the harness.

Other objects and advantages of this invention will become apparent to those skilled in the art upon reading the following specification when taken in conjunction with the accompanying drawings.

FIGURE 1 is an elevation view of a high pressure discharge lamp wherein the arc tube harness is shown positioned within a glass envelope.

FIGURE 2 is an illustration of the stamped arc tube ice harness of this invention before the various folding operations.

FIGURE 3 is a top plan view taken along the lines 33 of FIGURE 4. In this figure the bulbous glass envelope surrounding the arc tube is not shown.

FIGURE 4 is an illustration of a side elevational view of the unitary arc tube harness according to this invention, taken along the lines 44 of FIGURE 3.

In each of the figures, similar numerical designation will connote similar elements.

The invention will be illustrated with reference to a high pressure mercury vapor lamp since it is generally used in such construction, but the harness can also be used in other similar devices.

As will be seen in FIGURE 1, the unitary harness 1 for supporting the arc tube 15 is positioned generally in the central portion of the bulbous envelope 3. In order to obtain the maximum efliciency for the lamp, it is conventional practice to axially position the arc tube 15 in the bulbous envelope. However, if it is desired to rearrange the positioning, this axial relationship may be changed. The harness '1 comprises the two elongated, spaced struts 5 and 7. In most cases the struts 5, 7 can be substantially parallel, but other configurations can be used, if desired. The supporting cross arms 9 and 11 extend from one strut to the other and space them apart. Tabs attached to these arms hold the arc tube 15 in the bulbous envelope 3 in a generally co-axial position. Tabs 17 and 18 which extend from the upper supporting cross arm 9 serve as the upper attaching support for the arc tube. Extending from the lower supporting cross arm 11 is a generally U-shaped tab 19 which serves as the lower attaching support for the arc tube. These tabs are folded over the flattened end portions 61 of the arc tube and rigidly attach the arc tube to the harness. Also provided on each of the supporting cross arms are the stamped out guides 21 which are adapted to engage the sides of the pinched portions 61 of the arc tube and prevent its lateral movement in the harness. The electrical contact cross arm 23 extends between struts 5 and 7 and is positioned above the upper supporting cross arm 9. One electrode or" the arc tube is affixed to this cross arm. Generally the lead-in Wire 25 may be inserted in a suitable stamped portion 27. Although no welding is generally necessary for this attachment, it may be utilized if desired. In addition to providing an electrical contact, the cross arm 23 also increases the stability of the harness in the lamp and will provide transverse support for the upper portion of struts 5 and 7. Although the cross. arm 23 is shown as a horizontal bar, it is apparent that it may haveother shapes.

The resilient bumpers or bulb spacers 29, 28, 6 and 12 are in contact with the upper tubular portion of the glass envelope 3. These bumpers maintain co-axial positioning of the harness and are tube even when the lamp is subjected to shocks such as shaking and jarring. It is highly advantageous to have such resilient spacers in the lamp, and it is-quite important that they are a unitary part of the stamped-out harness. Prior attempts to fabricate a stamped-out harness have not provided such integral resilient spacers and it was necessary to rigidly position the upper portion of the harness in a protuberance in the glass envelope. It is apparent, however, that if it is desired to have an outer bulbous envelope of different construction, the harness may be adapted to be rigidly placed in the envelope without these bulb spacers. This type of positioning is obtained by eliminating the bulb spacers and extending the upper portion of the electrical contact cross arm 23 to generally fit in a protuberance in the envelope.

To protect the resistor 37 and diflfuse heat from the ends of the lamp, the heat shield 30 is positioned below the lower cross arm 11. An aperture 31 is provided in the central portion of the heat shield 30 so that the lead-in wires 33 and 35 will not contact the harness. Through the use of this aperture conventional tubular glass insulators around the wires 33 and 35 may be eliminated. If additional insulation is desired, however, they may be added.

In the lower portion of the unitary harness a cross arm 26 is provided to position the lamp in the bulbous envelope. The structurally stable lead-in wire 39 is inserted into the stamped-out portion 40 of the positioning cross arm 26. Spot welding may be utilized, if desired. This construction will insure the uniform positioning of the harness in the lamp and will provide a structurally stable base for the assembly. If it is desired to rotate the harness 90 about its longitudinal axis, the positioning of the stamped-out portion 40 may be offset from the co-axial so that there will be no electrical contact between the leadin wire 43 and the positioning cross arm 26.

In the sealing operations it is general practice to have gases pass in and out of the aperture 49 of the re-entrant stem press 46. A bafile is provided to prevent gases from directly contacting the bulbous glass envelope 3 as a stream and dislodging some of the coated phosphor. This batiie is positioned directly in front of the re-entrant aperture 49 and comprises the plate 45 and the stem 47. The stem 47 is bent around so that the plate may be placed directly in front of the aperture 49.

The remainder of the lamp is of substantially conventional construction. The glass of the envelope 3 is sealed to the threaded cap 53, which in turn is insulated from the electrical contact 55 by means of the insulating ring 57. In the same manner the arc tube 15 is of conven tional construction and comprises a light-transmitting envelope 59, normally fabricated of quartz, or similar heat resisting material. Seals 61 are conventionally provided at either end of the :arc tube. These seals may be either flattened, pinched portions or may assume a generally cylindrical shape. In the case of a seal having a generally cylindrical shape, the tabs 17 and the U-sha-ped support member 19 may be modified by providing elongations in order to suitably support the arc tube. Ribbon sealed conductors are sealed in each of the pinched or sealed portions 61. These conductors are attached at one end to each of the lead-in wires 35, 33 and 25. At the other end of the ribbon conductor the conventional electrodes 34 and starting electrode 36 are attached. For purposes of electron emission a thorium sliver is desirably included as part of the electrodes 34, which may be fabricated of tungsten for example, by conventional electrode construction methods. The are tube contains a selected charge of mercury and an inert ionizable gas such as and mm. of mercury of argon.

The metal used in the unitary harness should be strong, durable and heat resistant; it may be, for example, sheet stock such as 10 mil nickel-plated iron. Although this metal is quite strong in itself, it is often desirable to strengthen the harness by adding indentations 10' and 22. These indentations may be placed elsewhere on the harness where it is desired to have additional stability.

Reference is now made to FIGURE '2 which shows the stamped harness prior to its being bent into shape. The struts 5 and 7 have attached stiffening portions 4 and 8 which were adapted to be bent to an angle of about 90 with respect .to the struts. In this manner, although relatively thin and inexpensive sheet stock is used, the necessary structural stability is obtained. The upper supporting cross arm 9 has two tabs '17 and 18 extending from the upper portion thereof. These tabs are adapted to be bent around the pinched portion of the arc tube. Two tabs are used so that the lead-in wire 25 (as shown in FIGURE 1) may extend upwardly from the arc tube and no changes need to be made in the arc tube design. Two stamped-out guide means 21 are provided on the cross arm 9. These guides may be bent to an angle of about with respect to the supporting cross arm to provide lateral support for the arc tube.

A U-shaped tab 19 extends from the lower cross arm 11. In the central portion of this tab an aperture 32 is provided for the lead-in wires of the arc tube. The Wires 33 and 35 must be electrically insulated from the harness, since the harness is used as a means for conducting elec tricity to the other electrode. Two additional guide means 21 are provided on the lower cross arm 21; when bent out in the appropriate bending operation these guides will inhibit the lateral movement of the are tube in the harness.

The heat shield 30 is positioned beneath the cross arm 11. An aperture 3 1 is stamped in the central portion thereof for the passage of appropriate lead-in wires. The shield 30 is joined to the struts 5 and 7 and the supporting cross arm 11 by means of the bendable portion 14. The remainder of the heat shield is stamped through so that it may be bent to an angle of about 90, with respect to the cross arm.

Above the cross arm 9 is the electrical contact cross arm 23 having a stamped aperture 27. Indentations 10 may be added to improve stability. The stamped aperture is provided to permit the insertion of the lead-in wire 25 of the are tube (shown in FIGURE 1). Above the electrical contact cross arm is a series of four fingers or bumpers 12, 6, 28 and 29'. The bumpers attached to the same strut are bent in opposite directions to a position of about 90". As noted previously if it is desired to have a rigid construction rather than the resilient construction of this invention this entire upper portion of the harness, including the electrical contact 23, may be redesigned.

In the lower portion of the unitary harness the plate 45 is shown attached to stem 47. To fabricate the harness, plate 45 is bent 90 with respect to stem 47. The stem 47 is then angled back to place the plate 45 in front of the ire-entrant hole 41 (shown in FIGURE 1).

Thus the unitary harness is made of a single metal sheet, properly stamped and so designed whereby the ruggedness of previous wire harnesses is exceeded, and substantial savings in manual labor are realized. Furthermore, the number of spot welds needed to fabricate a lamp is markedly reduced.

FIGURES 3 and 4 are showings of the harness after the bendable portions are aligned in their appropriate positions. As is seen each of bumpers 12, 98, 6 and 28 are bent 90 in opposite directions so that they are in substantially parallel alignment. The heat shield 30 is bent upwardly about 90 and the plate 45 is bent 90 with the stem 47 helically bent to properly position it in front of the re-entrant hole.

In assembling the lamp, a suitable are tube 59 is placed on the cross arms, the guides 21 having previously been bent :out and the U-shaped tab 19 bent around the pinched portion 61. The lead-in wires 33 and 35 are placed through the aperture 32 in the U-shaped tab 19. After proper positioning is assured, the tabs 17' and 18 are bent around the upper portion 61 of the arc tube. This bending after positioning of the arc tube is quite important, since small differences in linear length of the arc tube will be compensated for and a rigid attachment of the arc tube to the harness will be insured. The electrical lead 25 is placed in the aperture 27 provided in the electrical contact cross arm 23 and spot welded if desired. Although an aperture is shown, this lead may be directly spot welded to the electrical contact cross-arm if desired. After the arc tube is positioned the electrical leads 33 are welded to lead-in wire 43. Electrical contact 55 has previously been welded to lead-in wire 43 which in turn is welded to the heat shield 30. The harness with the stem is then mounted in the bulbous envelope by conventional means. The cap 53 with insulation 57 and electrical contact 55 are sealed to the bulbous envelope and a finished lamp is produced.

It is apparent that changes and modifications may be made within the scope of the instant invention. It is my intent, however, to be limited only by the scope of the appended claims.

I claim:

1. A unitary harness for holding an arc tube comprising a single sheet metal frame stamped and shaped into a pair of elongated struts spaced from each other, a pair of supporting cross arms positioned transversely between said struts, means for attaching said arc tube to said supporting cross arms and means to position said harness in a bulbous envelope.

2. A unitary harness for holding an arc tube comprising a single sheet metal frame stamped and shaped into a pair of elongated struts spaced from each other, a pair of supporting cross arms positioned transversely between said struts, means for attaching the ends of said arc tube to said cross arms, said means comprising tabs extending from said supporting cross arms and adapted to fold about said ends and means to position said harness within a bulbous envelope.

3. A unitary harness for holding an arc tube comprising a single sheet metal frame stamped and shaped into a pair of elongated, spaced-apart struts, a pair of supporting cross arms transversely positioned between said struts, means for attaching saidare tube to said supporting cross arms, a heat shield positioned between said struts and below the lower of said supporting cross arms, means to position said harness within a bulbous envelope.

4. The unitary harness according to claim 3 wherein a means forming an aperture is positioned in the central portion of said heat shield.

5. A unitary harness for holding an arc tube comprising a single sheet metal frame stamped and shaped into a pair of elongated struts spaced from each other, a pair of supporting cross arms positioned transversely between said parallel struts, means for attaching said are tube to said supporting cross arms, an electrical contact cross arm positioned between said struts and above the upper of said supporting cross arms, said are tube adapted to be in electrical contact with said electrical contact cross arm and means to position said harness within a bulbous envelope.

6. A unitary harness for holding an arc tube comprising a single sheet metal frame stamped and shaped into a pair of elongated, spaced apart struts, elongated spaced apart stiffening means attached to each of said struts and in an angular relation therewith, a pair of spaced apart supporting cross arms transversely positioned between said struts, means for attaching said are tube to said supporting cross arms, and means to position said harness in a bulbous envelope.

7. A unitary harness adapted to hold an arc tube comprising a single sheet metal frame stamped and shaped into a pair of elongated struts spaced from each other, a pair of supporting cross arms positioned transversely between said struts, means to aflix the ends of said are tube to said cross arms, resilient bulb spacers attached to each of said struts and being positioned above the upper of said supporting cross arms and means to position said harness in said envelope.

8. A unitary harness adapted to hold an arc tube comprising a single sheet metal frame stamped and shaped into a pair of elongated, spaced apart struts, a pair of supporting cross arms positioned transversely between said struts, means to afiix said are tube to said supporting cross arms, a re-entrant aperture baffle attached to the lower portion of said unitary harness below the lower of said supporting cross arms, and means to position said harness within a generally bulbous envelope.

9. A unitary harness for supporting an arc tube having flattened end portions comprising, a single sheet metal frame stamped and shaped into a pair of elongated, substantially parallel struts spaced from each other, a pair of supporting cross arms transversely positioned between said struts, means to affix the ends of said are tube to said supporting cross arms said means comprising tabs extending from said supporting cross arms adapted to be folded around said flattened ends, an electrical contact cross arm positioned transversely between said struts above the upper of said supporting cross arms, a heat shield below the lower of said cross arms attached to and positioned between said struts, a re-entrant aperture bafile attached to the lower portion of said harness below the lower of said supporting cross arms, stiffening means attached to each of said struts positioned substantially parallel thereto and in an angular relationship therewith, resilient bulb spacers extending transversely from each of said struts, and means to position said harness within a generally bulbous envelope.

10. A high pressure discharge lamp comprising an arc tube, a transparent outer bulbous envelope around said tube but spaced therefrom, a unitary harness fabricated of a single stamped and shaped sheet metal frame for holding said tube, said harness comprising a pair of elongated struts spaced from each other, a pair of supporting cross arms positioned transversely between said struts, means for attaching said tube to said supporting cross arms, and means to position said harness in said bulbous envelope.

'11. A high pressure discharge lamp comprising, an arc tube, a transparent outer bulbous envelope around said tube but spaced therefrom, a unitary harness fabricated of a single stamped and shaped sheet metal frame for holding said tube, said harness comprising a pair of elongated struts spaced from each other, a pair of supporting cross arms transversely positioned between said struts, means for attaching said arc tube to said supporting cross arms comprising tabs extending from said supporting cross arms and adapted to fold about the ends of said are tube, and means to position said harness within said bulbous envelope.

12. A high pressure discharge lamp comprising, an arc tube having flattened end portions, a transparent outer bulbous envelope around said tube but spaced therefrom, a unitary harness fabricated of a single stamped and shaped sheet metal frame for supporting said are tube comprising a pair of elongated, substantially parallel struts spaced from each other, a pair of supporting cross arms positioned between said struts, means to aflix the ends of said are tube to said supporting cross arms, said means comprising tabs extending from said supporting cross arms adapted to be folded around said flattened ends, an electrical contact cross arm positioned transversely between said struts above the upper of said supporting 'cross arms, a heat shield below the lower of said cross arms attached to and positioned between said struts, a re-entrant aperture bafile attached to a positioning cross arm in the lower portion of said harness, stiffening means attached to each of said struts positioned substantially parallel thereto and in angular relationship therewith.

References Cited in the file of this patent UNITED STATES PATENTS 2,748,306 Thorington May 29, ,1956 2,749,462 Kenty June 5, 1956 2,802,961 Jenne Aug. 13, 1957 2,951,959 Fraser Sept. 6, 1960

Claims (1)

1. A UNITARY HARNESS FOR HOLDING AN ARC TUBE COMPRISING A SINGLE SHEET METAL FRAME STAMPED AND SHAPED INTO A PAIR OF ELONGATED STRUTS SPACED FROM EACH OTHER, A PAIR OF SUPPORTING CROSS ARMS POSITIONED TRANSVERSELY BETWEEN SAID STRUTS, MEANS FOR ATTACHING SAID ARC TUBE TO SAID SUPPORTING CROSS ARMS AND MEANS TO POSITION SAID HARNESS IN A BULBOUS ENVELOPE.

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