US3486065A

US3486065A - Means for centralizing an incandescible coil about the longitudinal lamp axis

Info

Publication number: US3486065A
Application number: US697363A
Authority: US
Inventors: Jack Martin
Original assignee: Westinghouse Electric Corp
Current assignee: Philips North America LLC
Priority date: 1968-01-12
Filing date: 1968-01-12
Publication date: 1969-12-23
Anticipated expiration: 1986-12-23

Description

Dec. 23. 1969 J. MARTIN 3,486,065

MEANS FOR CENTRALIZING AN INCANDESCIBLE COIL ABOUT THE LONGITUDINAL LAMP AXIS Filed Jan. 12, 1968 FIG! FIG.2

WITNESSES INVENTQR M1 ,-%.M Jock Morhn BY WM M w ATTORNEY MEANS FOR CENTRALIZING AN INCANDES- ClIBLE COIL ABOUT THE LONGITUDINAL LAMP AXIS Jack Martin, Paramus, NJ, assignor to Westinghouse Electric Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Filed Jan. 12, 1968, Ser. No. 697,363 Int. Cl. HOlj 1/88, 19/42 US. Cl. 313-271 3 Claims ABSTRACT OF THE DISCLOSURE An incandescible lamp wherein the longitudinal axis of an incandescible coil is positioned coincident with the longitudinal axis of the lamp envelope. The axial alignment of the coil within the lamp is achieved while using a coil wherein the end portions are displaced from the longitudinal axis of the coil. An axis translocating conmeeting and support member electrically connects the coil to the lead-ins which serve as support members. The axis translocating connecting member serves to align the coil axis coincident with the longitudinal lamp axis.

BACKGROUND OF THE INVENTION In many incandescent lighting applications it is desirable to have the longitudinal axis of the coiled incandescible element coincident with the longitudinal axis of the lamp envelope. This arrangement allows for ease of coupling the lamp to a reflector in general flood lighting applications. This axial alignment becomes more critical in tungsten-halogen lamps in order to insure a generally uniform envelope temperature along the length of the lamp to avoid localized condensation, and instability leading to localized heating and subsequent bulging of the bulb. This axial alignment is generally achieved by using a coil which is formed having extending leg portions directed along the longitudinal axis of the coil. When a coiled-coil element is used this is accomplished by inserting what is termed a button hook into the last turn of the secondary coil to provide an extension along the longitudinal axis of the secondary coil of the coiledcoil element.

In the fabrication of coils for use in incandescible lamps, the coil legs can easily be made parallel to or perpendicular to the longitudinal central axis of the coil by controlling the orientation of the mandrel with respect to the feed reel of wire. In order to align the coil legs along the longitudinal axis however, a separate operation is involved which requires bending the coil leg, or in the case of a coiled-coil element, adapting the last turn of the secondary coil by means of a button hook. The button hook is difficult to fabricate since a portion of it is curved at the pitch of the secondary coil for ease of insertion of the button hook into the last turn of this coil. The insertion of the button hook is a difficult operation and clamping or fastening of the curved button hook within the coil is a difficult operation.

The prior art includes a lamp combination in which an incandescible coil with leg portions displaced from the coil longitudinal axis is centered axially Within a double ended lamp. The non-axially aligned coil leg portions are mounted off-center of oversized ribbon seals thereby centering the coil on the longitudinal lamp axis. Of course this lamp combination is limited to double ended lamps. In a similar axially aligned lamp combination the off-center leg portions of the coil are sealed into the press area to support the coil and a fusible nited States Patent ice axially aligned support is electrically connected to the extending legs of the axially aligned coil.

SUMMARY OF THE INVENTION It is the object of the invention to provide in combination with an incandescible lamp means for axially aligning an incandescible coil with the longitudinal lamp axis.

It is another object to provide in a lamp combination means for utilizing an incandescible coil having extending leg portions that are displaced from the longitudinal coil axis in aligning the longitudinal coil axis coincident with the longitudinal lamp axis.

It is a further object to provide a single-ended incan descible lamp combination utilizing an axially aligned coiled-coil incandescible element having extending leg portions displaced from the coil longitudinal axis.

These objects and others that will become apparent as the description proceeds are achieved by providing a lamp combination utilizing a pair of axis translocating support and connecting members having coiled end portions and a central elongated portion to align an incandescible coil about the longitudinal lamp axis. The coiled end portions are respectively connected to a lead-in concluctor and one leg portion of the incandescible coil. The central portion is elongated to displace the coiled end portions a predetermined distance. The length of the central elongated portion is determined by the spatial relationship of the lead-in conductors to the extending coil leg portions. The longitudinal axis of the incandescible coil is made coincident with the central axis of the lamp envelope by means of the axis translocating support and connecting members.

DESCRIPTION OF THE DRAWINGS The invention can best be understood in reference to the accompanying drawings in which:

FIGURE 1 is an elevational view partly in section of a single-ended incandescible lamp combination;

FIG. 2 is a view partly in section of a double-ended incandescible lamp combination;

FIG. 3 is an elevational view partly in section of another single-ended lamp combination in which the leadins are offset from the longitudinal lamp axis; and

FIG. 4 is an enlarged view of a portion of the lamp combination shown in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention can best be understood by referring in detail to the accompanying drawings. The incandescible lamp 10 in FIG. 1 has a light transmissive envelope 12, and an incandescible tungsten coil element 14 enclosed within the envelope 12.. The coil 14 is electrically connected to the lead-in conductors 16 which are sealed through the outer envelope 12. The lead-in conductors 16 are brought through the press seal 18 by means of molybdenum ribbon seals 20 which are well known in the art. The press seal 18 is mounted within a suitable high temperature base 22 which is here shown as a screw-in type base with a ceramic insulating body and metallic contacts. The conductive lead-ins 16 extend in predetermined position within the envelope 12. The furthest extending portion of the conductive lead-ins 16 are aligned in the preferred embodiment coincident with the longitudinal axis of the lamp 10. The incandescible coil 14 is wound with an elongated central barrel portion 25 and extending leg portions 26 displaced from the longitudinal central axis of the coil. In the preferred embodiment in FIG. 1 the extending leg portions 26 are generally parallel to the longitudinal central axis of the coil and are displaced about a radius length from the coil longitudinal axis. The axis translocating connecting member 28 has coiled

end portions

30, 31 and a central elongated portion 32. The central elongated portion 32 extends a predetermined distance between the coiled

end portions

30, 31 thereby displacing the coiled end portions a distance which is determined so that when one coiled end portion is electrically connected to one conductive lead-in and the other coiled end portion is electrically connected to the extending leg portion of the incandescible coil, the longitudinal axis of the incandescible coil is aligned with the longitudinal axis of the lamp. An additional support member 34 is preferably mounted in the vitreous lead-in support 35 and connected to a central portion of the incandescible coil to prevent sagging of the coil In the preferred embodiment illustrated in FIG, 1, and a portion of which is enlarged in FIG. 4, a 250 watt incandescible lamp is shown and the invention will be described with respect to this combination. The combination can be used with various other size lamps and coils. The lamp envelope 12 is quartz and encloses a volume of about 3 cc. The lamp is filled to a pressure of about 2 atmospheres with a suitable inert gas or mixture such as an argon-nitrogen mixture. The lamp also contains an iodine dose of from 0.1 micromole to 1 micromole per cc. of lamp volume. The incandescible tungsten coil element 14 Which is here a coiled-coil member has a primary coil wound of 4.8 mil tungsten wire, wound with about a 28 mil diameter, and a pitch of 130 turns per inch. The secondary coil is wound from this primary coil and is about 108 mil in diameter with a pitch of about 22 turns per inch.

The extending leg portion 26 of the incandescible coil 14 in the preferred embodiment is actually an extension formed by the primary coil. The coiled-coil is wound and cut so that the leg portion 26 extends parallel to the longitudinal axis of the coiled-coil, A straight conductive member 36 such as a tungsten rod of suitable diameter is inserted into the primary coil and is welded therein. This straight conductive rod 36 is very easily inserted into the primary coil and allows for a simple welding operation.

The axis translocating support member 28 is preferably preformed by winding a coil with closed pitch and an inside diameter such that the lead-in conductors 24 and the conductive member 36 can be inserted therein. A central turn of this preformed coil is opened to form the elongated central portion 32 of the axis translocating member 28. The length of this central portion is adjusted to align the barrel of the coiledcoil element along the lamp axis when the member 28 is overfitted on the leadins 24 and the coil leg extensions 26.

The axis translocating support member 28 is preferably slipped over the lead-in conductor 24 and the coil leg extension 26 that is adjacent thereto. When both legs of the coil are thus supported and checked for alignment the lead-ins 24 and leg extensions 26 may be spot welded to the respective coiled-end portions. In the preferred embodiment the furthest extension of the lead-in conductors 24 are oriented along the lamp axis, the lead-ins can be oriented parallel to the lamp axis and the central elongated portion 32 must then be adjusted in length to bring the incandescible coil axis into coincident alignment with the lamp axis.

In another embodiment as shown in FIG. 2, a doubleended incandescible lamp combination 40 has a light transmissive envelope 38 and press seals 44 at each end. The conductive lead-ins 46 are sealed through press seals 44 by molybdenum ribbon seals 42. In this embodiment the conductive lead-ins again are disposed along the longitudinal lamp axis One coiled end portion 31 of the axis translocating connecting member 28 is overfitted on the furthest extension of the conductive lead-ins 46 while the other coiled end portion 30 is overfitted on the extending leg portion of the coil 48. The length of the central elongated portion 32 of this axis translocating connecting member is determined to align the incandescible coil axis with the longitudinal lamp axis.

In another embodiment as shown in FIG. 3, a singleended lamp combination 50 is provided wherein the conductive lead-

ins

52, 54 are not aligned on the longitudinal lamp axis. The central elongated portion 32 of the axis translocating connecting member is adjusted in length to allow for the axial alignment of the incandescible coil with the longitudinal lamp axis.

The incandescible coil 14 is shown wound with eleven complete turns. While the number of turns is not critical. the positions of the extending leg portions of the coil will be dependent upon whether the number of turns is an integer or a fractional number as shown by the coil in FIG. 3. The predisposed position of the lead-in conductors can be adjusted to complete the connection to the coil legs. The support means of the present invention provides a very stable and reliable means of electrically connecting and axially aligning the incandescible coil to withstand vibration and improve the reliability of the lamp combination.

Another advantage of the present combination is that the axis translocating support member can be used as a stop preventing coil expansion by adjusting the diameter of the axis translocating support member so that the primary coil of the incandescible coil will abut thereto and will not be able to fit therein.

The lamp combination of the present invention provides a simple yet effective design for aligning an incandescible coil about the longitudinal lamp axis, This design greatly simplifies the manufacturing and fabrication procedures in constructing such a lamp. The electrical connections and the mechanical structure of the present lamp combination is improved to provide insurance against vibrational failure.

It will be recognized that applicant has provided means in a lamp combination for axially aligning an incandescible coil with the longitudinal lamp axis. This has been provided for in a lamp utilizing an incandescible coil having leg portions displaced from the longitudinal coil axis. It is preferably utilized in a coil with a coiled-coil incandescible element in a single-ended incandescible lamp.

While the applicant has described the invention in detail with respect to specific lamp sizes and configurations. it is to be understood that the invention is not to be limited thereto or thereby.

I claim as my invention:

1. An incandescible light source comprising:

(a) a sealed elongated light-transmitting envelope;

(b) an elongated filament having an elongated coiled barrel portion positioned coaxially with the longitudinal axis of said envelope, and said filament having legs longitudinally extending from each end or" said coiled barrel portion and transversely displaced from the axis of said barrel portion;

(c) a pair of lead-in conductors sealed through said envelope and each terminating in predetermined position within said envelope proximate but transversely spaced from said legs of said filament; and

(d) a pair of support and connecting members connecting each said leg of said filament and the end portion of each said lead-in conductor proximate thereto, each said support and connecting member comprising two coiled members rigidly connected to each other at one end thereof, said coiled members transversely displaced a predetermined distance from each other, one said coiled member of each said support and connecting member snugly overfitting one extending leg of said filament and said other coiled member of each said support and connecting member overfitting the end portion of said lead-in conductor proximate thereto to support and electrically connect said elongated filament in axial alignment with the longitudinal axis of said envelope.

5 6 2. The incandescible light source as specified in claim 1, 3,210,587 10/ 1965 Vile 313271 wherein said lead-in conductors extend along said longi- 3,403,280 9/1968 Cardwell 313271 tudinal axis of the envelope. 3,441,772 4/1969 Cardwell 313271 X 3. The incandescible light source as specified in claim 1,

wherein said elongated filament is a coiled-coil and said 5 OHN W. HUCKERT, Primary Examiner filament legs comprise an extending support rod inserted A. J. JAMES, Assistant Examiner into the primary coil of said coiled-coil.

References Cited US. Cl. X.R.

UNITED STATES PATENTS 10 285 3,194,999 7/1965 Heinlein 3l32']l