JP2001160378A - Lamp with improved fuse - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a lamp with a Ballotini fuse incorporated in its flare. SOLUTION: A fuse for a lamp (10) is formed in a flare 40, and a lead (26) to a drivable light source (28), such as tungsten filament or the like passes through a cavity (58) inside the flare. The parts for each lead (60, 62) inside the flare cavity are made fusible. The flare cavity is filled, an arc-extinguishing filler (76), such as glass beads, etc., surrounding the fusible parts resolves the arc and the beads, are secured to the cavity by a sealant (86).

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION The present invention relates to lamp technology,
In particular, it relates to electric lamps incorporating a Ballotini type fuse in the flare.

In the manufacture of electric lamps, such as incandescent lamps and halogen lamps, a fuse is often used to protect the lamp from damage caused by arcing by interrupting the overcurrent. The fuse is typically composed of an elongated strip of metal or alloy, such as Monel or nickel D wire. However, if the filament breaks or the fuse burns out, one or more arcs will be generated internally. These arcs melt and pierce the lamp base and weld the base to the lamp socket. As a result, there is a risk of fire or personal injury. In the case of a halogen filament tube, the electric current at the time of arc generation ruptures the filament tube and damages the envelope of the lamp.

To reduce this arc, manufacturers have
Occasionally, the lamp base is connected to one or more insulating or
Filling with a porous cement layer insulates the conductive surface inside the base from the arc of the fuse wire. This type of solution requires additional steps in the manufacture of the lamp and is very expensive. Even if the melt penetration of the die is reduced, there is still a problem.

Therefore, it is of utmost importance to eliminate the arc as quickly as possible. One method of reducing arcing is to incorporate a commercially available barotini-type fuse into the lamp as a separate component. Barotini-type fuses consist of short diameter tubes (typically 2-3 millimeters in diameter) filled with glass beads or other arc-extinguishing material. The fuse wire is centered within a tube filled with glass beads. When the overcurrent fires the fuse, the fuse wire melts and the arc is immediately extinguished by the glass beads. The arcing time is significantly reduced compared to a fuse without beads.

[0005] In addition, the supply current during arcing and the energy flowing into the lamp are much lower than without beads, reducing the possibility of damage. However, the use of a Barotini-type fuse requires that its components be manufactured separately, complicating the lamp assembly process.

The present invention provides a new configuration of a lamp and a method of forming the same, which is improved to overcome the above and other problems.

SUMMARY OF THE INVENTION An exemplary embodiment of the present invention provides a lamp. The lamp includes a light transmissive envelope and an activatable light source within the envelope. The flare extends into the envelope and the flare comprises an internal cavity. A light source activatable by a plurality of leads is connected to a power supply. These multiple leads extend into the flare cavity. A portion of the at least one lead is a fusible element.

[0008] An arc-quenching filler is disposed within the interior cavity around the at least one fusible element.

[0009] In another exemplary embodiment of the present invention, a flare for a lamp is provided. The flare includes a hollow tubular portion defining an internal cavity. An exhaust pipe extends into the internal cavity,
A space is formed between the tubular portion and the exhaust pipe. A light source activatable by a plurality of leads is connected to a power source. The plurality of leads extend through a space within the flare internal cavity. A portion of the at least one lead is a fusible element. The first end of the tubular portion is sealed around the exhaust pipe and the lead to close the first end of the internal cavity. An arc-quenching filler is disposed in a space within the flare internal cavity around the at least one fusible element.

[0010] In another exemplary embodiment of the present invention, a method for forming a lamp is provided. In the method, the hollow tube is provided with a first open end and a second open end, and an exhaust pipe is positioned within the hollow pipe to define an annular space between the exhaust pipe and the hollow pipe. Further, the method positions a plurality of leads within the annular space. Here, at least one of the plurality of leads includes a fusible element. Further, the method seals the first end of the hollow tube and closes the first end of the annular space.
Here, a lead end extends into the sealed first end. An arc extinguishing material is placed around the fusible element in the annular space.

One of the advantages of the present invention is that arcing is minimized and lamp damage is minimized.

Another advantage of the present invention is that the manufacture of the lamp is simplified.

Further advantages of the present invention will become apparent to those skilled in the art from reading and understanding the following detailed description of the preferred embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 1 and 2, an incandescent lamp 10 includes a light transmitting glass envelope 12 secured to a base 14. The envelope shown in FIG. 1 comprises a spherical upper portion 16 and a narrower, generally cylindrical lower portion 18, although other envelope geometries are possible. It should be understood that the terms "upper" and "lower", "upper" and "lower" refer to the lamp of FIG. 1 in which the base extends below the envelope.

The base is made of metal shell 20, insulating plug 2
2. A standard contact 24 is provided. A power supply (not shown) is connected to an energizable light source 28, such as a coiled tungsten filament, located in the bulb 16 of the envelope using a four-part connection lead 26. The four-part lead is connected to the light source 28 and has supporting leads 30 and 32 such as nickel or nickel-plated copper wire for supporting the light source 28. As with incandescent halogen lamps, a filament tube (not shown) may surround the filament. Other light sources are also conceivable.

A generally cylindrical flare or recessed stem mount 40 is seated within the envelope. Flare is
It is in close contact with the bottom periphery of the cylindrical portion 18 of the envelope around its lower end 42. Exhaust pipe 46 extends axially into the flare and is sealed at its lower end to contain an inert gas, such as a mixture of nitrogen and argon, or to hermetically seal an evacuable envelope.

Extending into the press-on portion 54 of the flare 40,
Each support lead 30, 32 is connected to an intermediate part line 50, 52 formed from, for example, a DUMET line, which is sealed therein. The press-on portion seals around the upper end of each of the intermediate part lines, the lower ends of the support leads 30, 32, and the upper end of the exhaust pipe. Therefore, flare 4
Within the flare between 0 and exhaust pipe 46, a hollow or generally annular cavity 58 is formed.

Part lines 50, 52 extend into the flared cavity 58 at their lower ends. Here, they may be Monel or other nickel alloys, for example nickel 211
To the respective fusible elements such as the fuse lines 60 and 62 of FIG. Monel is a nickel / copper alloy. A preferred fuse wire is 63-70% nickel with up to 0.3% carbon, up to 2.0% manganese, up to 0.24% sulfur, up to 0.5% silver, the balance copper. It is composed of Monel 400 having a certain composition. Further, other materials that melt when an overcurrent is applied can be used as the fusible material.

The fuse wires are connected to external leads 70, 72 at their lower ends within hollow portion 58. And
The outer leads 70, 72 are connected to the central contact 24 and the upper rim of the shell 20, respectively, as shown in FIG.

The flare cavity 58 is filled with an arc-extinguishing filler 76. When an electric arc is generated (typically as a result of one of the fuses melting when an overcurrent flows), the fill 76 extinguishes the arc quickly. Since the arc extinguishing material is melted and evaporated by the arc, the ions in the arc space disappear. The filler is preferably in particulate form and is not conductive. Also, the material has low thermal conductivity. Suitable arc-extinguishing materials include glass beads, silica sand, quartz sand, gypsum, chalk, and other well-known arc-extinguishing fillers, and combinations thereof. Beads or other arc-extinguishing materials preferably surround the fuse and are preferably tightly packed in the cavity. This material may be a binding filler in which sand particles are bound, for example, with colloidal silica particles. Without beads, the arcing time is quite long.

Optionally, fuse lines 60, 62
Is wound around a core (not shown). This core is a support core,
Alternatively, a core formed from a frozen mixture of an arc extinguishing material and a liquid may be used. Next, the core around which the fuse is wound is further surrounded by additional arc-extinguishing material. If this frozen wick is used, it melts and the liquid evaporates before use.

Either one or both of the leads 26 can be provided with a fuse line. For best results in the preferred embodiment, both leads have fuse line portions 60,62.

When an overcurrent flows, the fuse lines 60 and 62
Melts and the arc is quickly extinguished by glass beads or other arc-extinguishing material. Without glass beads, the arcing time is typically about 5 milliseconds. With the addition of the beads, the arcing time is reduced to about 2 milliseconds.

To form the lamp, the support leads 3
0, 32, connection leads 50, 52, fuse wires 60, 6
2, and each four-part lead 26 with external leads 70, 72 is inserted into the first upper open end 80 of the flare and the exhaust pipe 46 is axially positioned within the flare 40 as shown in FIG. You. As shown in FIG.
The upper end 80 of the flare is hermetically sealed around the connection lead by heating and pressing at the position of. Next, as shown in FIG.
The flare is sealed around 2. The envelope is evacuated through an exhaust pipe 46, and if nitrogen / argon (or krypton or xenon) is used instead of argon, it is loaded into the envelope via an exhaust pipe and the exhaust If necessary, exhaust the enclosure. Next, the lower end 82 of the exhaust pipe is "tip-off" to hermetically seal the filler in the envelope, as shown in FIG. 5, or to vacuum. This is made possible by mechanical sealing or melting the glass.

Glass beads 76 or other particles are inserted into the flared cavity 58 via the open end 84,
The fuse lines 60 and 62 are surrounded as shown in FIG. As best shown in FIG. 2, the lower end 84 of the cavity is sealed with a seal 86, for example, an epoxy-based adhesive, a silicone sealant such as RTV, or other sealant. The seal formed need not be a hermetic seal; it is sufficient to retain the beads 76 in the cavity 58. The lamp forming process is completed by attaching the base 14 to the connection leads 70 and 72 and to the lower end of the bulb.

In another manufacturing method, beads are inserted into the flare cavity around the fuse before sealing the flare to the envelope. As described above, the filler is placed in the envelope, and the bottom end of the exhaust pipe is sealed. In most cases, the first method is preferred over the present method. This is because the flare can be formed integrally with the envelope. Other methods of assembling the lamp are also conceivable.

Therefore, as a part of the lamp assembling process, a flare incorporating the barotini-type fuse according to FIGS. 1 and 2 can be manufactured. This process can be easily automated to eliminate the need to specially manufacture a Barotini-type fuse.

The invention has been described with reference to the preferred embodiment. Obviously, modifications and alterations can be made by reading and understanding the above detailed description. It is intended that the invention be construed as including all modifications and alterations in the scope of the appended claims and their equivalents.

[Brief description of the drawings]

FIG. 1 is a front sectional view of a lamp of the present invention.

FIG. 2 is an enlarged sectional view of the flare with a barotini type fuse of FIG. 1;

FIG. 3 is a side sectional view of the flare when the lamp of FIG. 1 is formed.

FIG. 4 is a side view of the flare of FIG. 3 after sealing to a lamp envelope.

FIG. 5 is a side view of the lamp envelope and flare of FIG. 4 after tip-off sealing of the exhaust tube and filling of the flare cavity with glass beads.

Continued on the front page (72) Inventor Laszlo Victor Rieskovskiy, United States, Ohio, Mayfield Heights, Apartment 156, Mayfield Road, No. 6809 (72) Inventor Robert Joseph Berkey United States of America, Lorraine, Ohio, Lakeview Avenue, No. 1804

Claims (20)

[Claims] 1. A light-transmissive envelope, an energizable light source in the envelope, a flare extending into the envelope and having a cavity therein, and a power source powered by the energizable light source. A plurality of leads for electrical connection, wherein the leads extend into the cavity of the flare, at least one portion of which comprises a fusible element; and Lamp with an arc-extinguishing filler disposed around the sexual element. 2. The lamp of claim 1 wherein said arc-extinguishing filler is at least one of the group consisting of glass beads, silica sand, quartz sand, gypsum, chalk, and combinations thereof. 3. The lamp of claim 2 wherein said arc-extinguishing filler comprises glass beads. 4. The lamp of claim 1, wherein said fusible element comprises a fuse wire. 5. The lamp of claim 1, wherein each of the two leads includes a fusible element. 6. The lamp of claim 1, further comprising a seal holding the arc-quenching filler within the flare. 7. A hollow tubular portion defining an internal cavity, and an exhaust pipe extending into the internal cavity, wherein the exhaust pipe defines a space between the tubular portion and the exhaust pipe. A plurality of leads for connecting a light source and a power source, extending through the space into the internal cavity of the flare,
A lead having at least one portion thereof comprising a fusible element; a first end of the flare sealed around the exhaust pipe and the lead to close the first end of the internal cavity; A flare for a lamp comprising an arc-extinguishing filler material disposed around the at least one fusible element in the space of the flare interior cavity. 8. The flare of claim 7, wherein said arc-extinguishing filler is at least one of the group consisting of glass beads, silica sand, quartz sand, gypsum, chalk, and combinations thereof. 9. The flare of claim 8, wherein said arc-quenching filler comprises glass beads. 10. The flare of claim 7, wherein said fusible element comprises a fuse wire. 11. The flare of claim 7, wherein each of the two leads includes a fusible element. 12. The flare of claim 7, further comprising a seal at a second end of the flare, the seal holding the arc-extinguishing filler material in the interior cavity space of the flare. 13. A method for forming a lamp, comprising: providing a hollow tube having a first open end and a second open end; positioning an exhaust tube within the hollow tube; Defining an annular space therebetween; and positioning a lead in the annular space, wherein at least one of the leads includes a fusible element.
Sealing the first end of the hollow tube and closing the first end of the annular space, wherein the end of the lead extends into the sealed first end. And arranging an arc extinguishing material around the fusible element within the annular space. 14. The method of claim 13, further comprising the step of connecting an energizable light source to an end of said lead extending into said sealed first end. 15. Sealing a second end of the annular space,
14. The method of claim 13, further comprising retaining the arc extinguishing material in the annular space. 16. The method of claim 13, wherein said arc-quenching filler is at least one of the group consisting of glass beads, silica sand, quartz sand, gypsum, chalk, and combinations thereof. 17. A method for sealing the hollow tube to an envelope near the second open end of the hollow tube to define an interior space accessed by the exhaust tube in the envelope. 15. The method of claim 14, further comprising: 18. The method according to claim 18, wherein the step of placing an arc extinguishing material around the fusible element within the flare includes connecting the hollow tube to the envelope near the second open end of the hollow tube. 18. The method of claim 17, wherein said step of sealing is performed. 19. The method according to claim 19, wherein, prior to the step of placing an arc extinguishing material around the fusible element within the flare, sealing an end of the exhaust pipe and surrounding the light source within the envelope. 18. The method of claim 17, further comprising the step of forming a hermetically sealed space. 20. The method of claim 13, further comprising applying an electrical current to the lead, wherein the arc extinguishing material extinguishes an arc formed when the fusible element melts.