US3621317A

US3621317A - Spring flip-top mount support for mercury vapor discharge lamp

Info

Publication number: US3621317A
Application number: US46382A
Authority: US
Inventors: Robert E Kerr
Original assignee: Westinghouse Electric Corp
Current assignee: Philips North America LLC
Priority date: 1970-06-15
Filing date: 1970-06-15
Publication date: 1971-11-16
Anticipated expiration: 1988-11-16
Also published as: CA937277A

Abstract

In a gas discharge lamp of the mercury vapor type, an improved upper support member for the arc tube mount assembly which comprises a leaf spring member rotatably secured to the upper crossbar element of the arc tube support frame which, during lamp assembly, enters the outer bulb in a position canted only slightly from axial alignment with the mount but rotates to a position perpendicular to the axis of mount assembly when in an assembled position against the top of the outer bulb to support and retain the arc tube mount in an axial position within the outer bulb.

Description

United States Patent Inventor Robert E. Kerr Chester, NJ.

Appl. No. 46,382

Filed June 15, 1970 Patented Nov. 16, 1971 Assignee Westinghouse Electric Corporation Pittsburgh, Pa.

SPRING FLIP-TOP MOUNT SUPPORT FOR MERCURY VAPOR DISCHARGE LAMP [56] References Cited UNITED STATES PATENTS 2,671,183 3/1954 St. Louis et al. 313/25 X 2,904,710 9/1959 Beeninga et al. 313/25 Primary ExaminerRoy Lake Assistant Examiner-Palmer C. Demeo Attorneys-A. T. Stratton, W. D. Palmer and Blair Studebaker ABSTRACT: In a gas discharge lamp of the mercury vapor type, an improved upper support member for the arc tube mount assembly which comprises a leaf spring member rotatably secured to the upper crossbar element of the arc tube support frame which, during lamp assembly, enters the outer bulb in a position canted only slightly from axial alignment with the mount but rotates to a position perpendicular to the axis of mount assembly when in an assembled position against the top of the outer bulb to support and retain the arc tube mount in an axial position within the outer bulb.

PATENTEDuuv 16 Ian FIG. lcl

FIG. lb

FIG. 4

WITNESSES INVENTOR Robert E. Kerr 444m ATTORINEY SPRING FLIP-TOP MOUNT SUPPORT FOR MERCURY VAPOR DISCHARGE LAMP BACKGROUND OF THE INVENTION This invention relates to gas discharge lamps of the highpressure mercury vapor type and more particularly to an improved upper support member for the arc tube mount of a gas discharge lamp.

Conventionally the outer bulb of a mercury vapor discharge lamp or metal halide additive lamp is generally what is known in the art as a bulbous tubular bulb which means that the neck and dome of the outer bulb are of the same or substantially similar diameters and cylindrical in cross section while the portion intermediate the neck and the dome tends toward the spherical or bulbous configuration. Because of the weight and configuration of the inner, arc tube mount and support structure in a mercury vapor lamp, it is necessary to support the structure from the dome of the bulb as well as from the flare or base of that structure. Presently, the top support for the arc tube mount structure consists of a pair of leaf spring members which are secured to the upper edges of the mount framework and which are, when the mount is sealed inside the bulb, compressed inside the dome of the bulb and rigidly hold the mount in position. To provide sufiicient retention in the dome of the bulb the uncompressed springs must have an effective diameter greater than either the neck or dome diameter through which the mount must enter the bulb during assembly. A typical illustration of this leaf spring construction, as is presently conventionally employed and which frictionally engages the upper tubular portion or dome of the lamp envelope is illustrated in US. Pat. No. 3,334,26l to K. H. Butler et al.

One significant problem which has been found when the conventional leaf spring construction is employed pertains more specifically to those lamps which include a silica or phosphor coating on the inner surface of the outer bulb. Since in order to provide sufficient support the leaf springs in their uncompressed state must have a greater effective diameter than the diameter of the tubular portions of the bulb, when the mount is inserted into the lamp and the springs members are compressed to conform to the smaller diameter of the tubular portions of the bulb the pressure brought to bear by the compressed springs against the inner coating of the bulb causes that inner coating to, in many instances, be scraped off or at least marred both in the tubular neck portion and in the tubular dome portion of the lamp. This problem is magnified many times over when a totally tubular bulb is employed rather than the bulbous tubular bulb since the compressed springs, acting with some force against the inner surface of the outer bulb, must traverse the entire length of the tubular bulb in contact with the bulb wall when the arc tube mount is inserted into the bulb.

SUMMARY OF THE INVENTION The above described deficiencies of the prior art are obviated by the present invention by providing: in a gas discharge lamp which includes an elongated outer bulb, a base sealed to the outer bulb, and elongated arc tube electrically connected to the base through a rigid lower support and an arc tube mounting frame connected as one end to the rigid lower support; the improved upper support for the elongated arc tube and are tube mounting frame which comprises a rotatable spring clip pivotally connected to the upper end of the arc tube mounting frame at approximately the mid point of the spring clip. This spring clip is adapted to enter the bulb in a position canted only slightly from axial alignment with the elongated arc tube and are tube mounting frame and rotates upon contact with the upper end of the bulb to a position substantially perpendicular to the axis of the elongated arc tube to thereby retain the upper end of the arc tube mounting frame in fixed axial alignment within the outer bulb.

BRIEF DESCRIPTION OF THE DRAWING Many of the attendant advantages of the instant invention will become more readily apparent and better understood as the following detailed description of an exemplary embodiment of this invention is considered in connection with the accompanying drawing in which:

FIGS. 1a, lb and lie illustrate sequentially the positioning of the arc tube mounting structure, employing the novel fliptop spring clip of this invention, within an outer envelope;

FIG. 2 is a front elevational view of the upper portion of the arc tube support frame illustrating the preferred embodiment of the invention;

FIG. 3 is a side-elevational view of the upper end of the are tube mounting frame of this invention; and

FIG. 4 is a front-elevational view of an entire sealed gas discharge lamp employing the upper mount support of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now in detail to the drawing wherein like reference characters represent like parts throughout the several views, there is illustrated in FIG. 4 a high-pressure gas discharge lamp constructed in accordance with the present invention and generally designated 10. The lamp includes a bulbous tubular outer glass envelope generally designated 12 having a neck portion 14, an intermediate bulbous portion 16 and a top or dome 18. The neck portion 14 and the dome portion 118 are substantially tubular and have generally a common diameter. The bulb I2 is sealed to a standard mogul base 20 which is electrically connected by

lead wires

22 and 24 through a stem press or flare 26 to the .arc tube electrodes.

The are tube 28 and are tube mounting and support frame 30 are mounted between the upper inwardly extending ends of lead-in

conductors

22 and 24 and the top or dome 18 of the bulb 12. The lower electrode of the arc tube 28 is electrically to the lead-in conductor 24 by a flexible connector 32 while the mounting and support frame 30 is rigidly connected to the lead-in conductor 22. The are tube 28 is rigidly supported on the mounting and support frame 30 by a pair of cross-straps 34 which grip the arc tube at the press seal on each end thereof. The upper operating electrode is electrically connected to the mounting and support frame 30 by means of an upper flexible conductor 36. As best illustrated in FIGS. 2 and 3 the mounting and support frame 30 includes at its upper end a crossbar member 38 which interconnects the two parallel

upright members

30a and 30b. Rotatably mounted to the crossbar member 38 is the flip-top mounting spring of the present invention. The mounting leaf-type spring 40 is mounted to the crossbar 38 by means of a pair of tabs or fingers 42 cut from the edge of the leaf spring member approximately midway along its length. The tabs 42 secure the leaf spring member 40 to the crossbar 38 but permit the leaf spring to rotate about the crossbar 38. At the ends of the leaf spring member are upstanding resilient fingers 44 which are formed by cutting the end edge and bending the finger at an angle with respect to the plane of the leaf spring member. The leaf spring member 40 may also include

apertures

46 and 48 therein which reduce the weight of the leaf spring, render it more flexible and may serve to control the weight of each end of the leaf spring. For example, the aperture 48 being larger than the aperture 46 causes that end or half of the leaf spring member 40 to be lighter than the end or half carrying the aperture 46 and there fore causes the heavier end to pivot downwardly with respect to the mount due to the additional weight in that end or half in a seesaw fashion. The leaf spring member is prohibited from rotating in a 360 are about the crossbar 38 due to the upper electrical connector 36 which serves as a stop and limits the leaf spring from rotating a full 360 about the crossbar 38.

Referring now to FIGS. la, lb and It, one of the principle advantages of the upper support member of this invention will be described. As indicated, conventional mounting frames employ a pair of leaf springs attached to the mounting and support frame 30 which must be depressed as the lamp is assembled or more specifically while the upper end of the mount is traversing the tubular neck and tubular dome of the bulb. This has the deleterious effect of scraping off or marring a portion of the inner phosphor or silicon coating of the outer bulb particularly in the neck and dome areas. Furthermore the prior art support requires more exacting tolerances in mount construction. As will be apparent from FIGS. 1a, lb, and 1c, as the mount structure of this invention enters the neck 14 of the outer bulb the upper retaining leaf spring or spring clip 40 is centrally located and canted only slightly from axial alignment with the elongated arc tube and are tube mounting and support frame (FIG. la). As the mount structure reaches the top of the bulb during assembly (FIG. lb) the upper edge of the spring member 40 and the upper spring finger 44 contact the dome of the bulb causing the spring to pivot about the cross member 38 as the mount proceeds into the bulb. When the mount is fully positioned within the outer bulb 12 the leaf spring member 40 will have reached the position illustrated in FIG. lc with the upwardly extending resilient fingers 44 resiliently pressing against the inner top wall of the dome l8, and the end edges of the leaf spring 40 will be resiliently engaging the tubular sidewalls of the dome 18. When the mount is in this position the stem press and flare 26 is then sealed into the neck of the bulb l4 and the bulb mounted and electrically connected to the mogul base 20.

As will be apparent from the foregoing the resilient rotatable leaf spring 40 of this invention permits the arc tube mount and support to be positioned within the outer bulb 12 without undesirable contact with the bulb wall during the insertion process but, upon complete insertion of the arc tube mount within the bulb 12, the resilient rotatable leaf spring 40 will have rotated to a position which is substantially perpendicular to the axis of the arc tube and arc tube mounting and support frame and will coact with the interior surface of the upper end or dome of the bulb to provide a resilient yet rigid support for the upper end of the arc tube mounting and support frame.

What is claimed is:

1. In a gas discharge lamp which includes an elongated outer bulb, a base sealed to the outer bulb and an elongated arc tube electrically connected to said base through a rigid lower support and supported within said bulb by an arc tube mounting frame connected at its one end to said rigid lower support, the improved upper support for said elongated arc tube and arc tube mounting frame which comprises: a spring clip rotatably connected to the other end of said are tube mounting frame at approximately the center of said spring clip, said spring clip adapted to enter said bulb in a position canted only slightly from axial alignment with said elongated arc tube and are tube mounting frame and to rotate upon contact with the upper end of said bulb to a position substantially perpendicular to the axis of said elongated arc tube to thereby retain the upper end of said arc tube mounting frame in a fixed position with respect to said outer bulb.

2. A gas discharge lamp according to claim 1 wherein said spring clip is an elongated metallic leaf spring having resilient fingers extending angularly from the plane of said leaf spring, said fingers being constructed and arranged to coact with the top of said bulb when said lower support and said bulb are secured to said base to rigidly retain, in combination with the end edges of said leaf spring, said supporting frame in a fixed position within said outer bulb.

3. A discharge lamp according to claim 2 wherein said spring clip includes a pair of gripping tabs adjacent its longitudinal center which grip said other end of said are tube mounting frame and constitute said rotatable connection between said spring clip and said are tube mounting frame.

4. A gas discharge lamp comprising: an elongated outer bulb and a base sealed to said elongated outer bulb, electrical conductor and support means mounted within said base and extending into the lower portion of said bulb, an arc tube support frame centrally disposed within said outer bulb electrically connected to and supported at its lower end by said electrical conductor and support means; an arc tube rigidly supported by said frame within said outer bulb and electrically connected at one end to said electrical conductor and support means and at its other end to said frame; and leaf spring means rotatably mounted adjacent its center to the upper end of said frame, said leaf spring means being constructed and arranged to rotate to a position perpendicular to said frame and coact with the upper end of said bulb to thereby restrain the upper end of said frame from lateral movement with respect to said bulb.

5. A gas discharge lamp according to claim 4 wherein said leaf spring means is an elongated metallic leaf spring having resilient fingers extending angularly from the plane of said leaf spring, said fingers being constructed and arranged to coact with the top of said bulb when said electrical conductor and support means and said bulb are secured to said base to rigidly retain, in combination with the end edges of said leaf spring, said support frame in a fixed position within said bulb.

6. A discharge lamp according to claim 5 wherein said leaf spring means includes a pair of gripping tabs adjacent its longitudinal center which grip said frame to thereby provide said rotatable mounting of said leaf spring means to said frame.

7. A discharge lamp according to claim 6 wherein said leaf spring means has included therein substantial apertures on each side of its center of rotation about said frame, said apertures increasing the flexibility of said leaf spring means.

8. A discharge lamp according to claim 7 wherein the remaining portion of said leaf spring means surrounding said apertures is greater on one half of said leaf spring means than on the other half.

Claims

1. In a gas discharge lamp which includes an elongated outer bulb, a base sealed to the outer bulb and an elongated arc tube electrically connected to said base through a rigid lower support and supported within said bulb by an arc tube mounting frame connected at its one end to said rigid lower support, the improved upper support for said elongated arc tube and arc tube mounting frame which comprises: a spring clip rotatably connected to the other end of said arc tube mounting frame at approximately the center of said spring clip, said sprIng clip adapted to enter said bulb in a position canted only slightly from axial alignment with said elongated arc tube and arc tube mounting frame and to rotate upon contact with the upper end of said bulb to a position substantially perpendicular to the axis of said elongated arc tube to thereby retain the upper end of said arc tube mounting frame in a fixed position with respect to said outer bulb.

3. A discharge lamp according to claim 2 wherein said spring clip includes a pair of gripping tabs adjacent its longitudinal center which grip said other end of said arc tube mounting frame and constitute said rotatable connection between said spring clip and said arc tube mounting frame.