US2405789A - Multifilament lamp - Google Patents

Description

Aug. 13, 1946. J. H. HOMRIGHOUS I 8 I MULTIFILAMENT LAMP Original Filed Aug. 22. 1942 FIGI IN V EN TOR.

Patented Aug. 13, 1946 UNITED STATES PATENT OFFICE Divided and this application November 1, 1943, Serial No. 508,453

13 Claims. 1

This application is a division of application Serial Number 455,747, filed August 22, 1942.

This invention relates in general to improve ments in electric lamps, and more particularly to lamps having a plurality of heating units or filaments.

One of the main objects of this invention is to provide means for prolonging the useful life of electric lamp bulbs.

Another object of this invention is the provision of switching mechanism inside the evacuated envelope for automatically changing the filaments or the heating units when one is burned out.

Several multi filament lamps have been devised, but in none of these is the switching mechanism rotatably mounted in the evacuated bulb and controlled by bimetallic strips or member supported inside the tube which are flexed into contact when a filament is disrupted.

These and other objects and. advantages will be apparent from the following detailed description, reference being had to the accompanying drawing in which:

Figure l is a side elevation partially in section of an illuminating bulb with filament switching mechanism.

Figure 2 is a top detail view of the rotary switching mechanism in Figure 1.

Figure 3 is a detail view of mechanism taken on line 33 in Figure 1.

Figure 4 is-a detail end view of rotary switch mechanism taken in the direction of the arrow 4 in Figure 2 including fragmentary portions of brush and upport.

Figure 5 is a schematic of the circuit used with the electric lamp.

In the drawing the reference numeral l represents a bulb or tube broken away to show the filament or heating unit switching mechanism on the inside of the evacuated bulb. In the center of this bulb is a hollow stem 4 extending upward from the base and having two ceramic disks 5 and 6 pivotally mounted near its upper extremity. The disk 5 has two pins 1 and 8 secured thereto for supporting one end of the filaments or heating units 9 and ID. The pins 1 and 8 are connected together by the bar I l The disk 6 mounted on the opposite side of the stem 4 also has two pins I2 and I3 shown in Figure 2 for supporting the other ends of the heating or lighting units 9 and III. A stabilizing bar i4 is securely fastened to the disks 5 and 6 so that they will rotate together. The disks are limited in their travel by the pin l5 engaging the elongated slot in the lower rim of the disk 5. The disks Sand 6 are at first held in the position shown in Figure l by the combination of the link l6 secured to the stabilizing bar M with a fuse metal link connector ll, reference to Figure 4, joining it with the bar l3 which in turn is secured to the ceramic or porcelain plate IS. The spring 28 secured to the disk 6 and to the plate I9 is for rotating the disks 5 and. 6 in a clockwise direction when the fuse link ii is broken.

The porcelain plate I9 near the bottom of the bulb has two bimetalic strips 2| and 22 rigidly secured thereto and having their upper contacting extremitie 23 and 24 extending in quadrants about the stem 4 shown in Figure 3. These movable members or bimetallic strips are provided with coil of resistance wire 25 and 25 to heat the bimetal to cause them to flex in a counter clockwise direction. The plate is also provided with a contact spring 2? for contacting the pins 12 and I3.

The operation of the switching mechanism shown in Figures 1 to 4 is as follows, reference being had to Figure 5. The source of current supply may be connected through conductor 23, link l6, coil 26, connecting bar ll, pin 7, heating unit 9, pin l2, wiping contact spring 21, and conductor 29, leading to the source of power supply. The heating unit 9 in serie with coil 25 will now be energized in multiple with the heating coil 25.

The heating coil 25 and 26 will cause the bimetallic strips 2! and 22 to flex in a counter clockwise direction. However, should the heating unit 9 burn out Or open the circuit through the coil 26 the bimetallic strip 22 would return to normal position, to contact the strip 2|, thus closing a circuit momentarily through the fuse link i1, bar l8, spring 22, contacts 24 and 23, strip 2! and conductor 29. This circuit will cause the fuse link ii to fuse or melt thu allowing the disks 5 and 6 to be rotated by the spring 26 to place the heating unit Ii] across the conductors 28 and 29.

The embodiments of the invention which have been given herein are illustrations of how the various features may be accomplished andof the principles involved. It is to be understood that the invention contained herein is capable of embodiment in many other forms and adaptations, without departing from the spirit of the invention and the scope of the appended claims.

Having thu described my invention, I claim:

1. In an electric lamp, a pair of filaments. a current supply circuit, spring controlled rotatable mechanism for supporting said filaments, said mechanism arranged to connect any one of said filaments in predetermined position to said current supply circuit, a fusable element for holding said mechanism under tension of said spring to maintain one of aid filaments in said position, an automatic switch comprising a pair of spaced bimetallic contact members adapted to be actuated into contact to connect said element to said supply circuit, and means for closing said contact member responsive to the disruption of the connected filament to open said link thereby releasins said mechanism to rotate another one of said filaments to said predetermined position, and to connect said other filament to the said current supply circuit.

2. In an article of manufacture, a plurality of electrical circuit elements, switching mechanism for controlling the energizing circuit for said elements, a fusible link for holding said mechanism under tension, an automatic switch comp-rising a first bimetallic strip and a second bimetallic strip each having portion disposed with a relatively energized coil for moving away from said second strip, and sensitive to the disruption of the energizing circuit in said first element for moving into engagement with said second strip, thereby disrupting said link to release the said mechanism for energizing a second one of said circuit ele ments.

3. In an evacuated bulb a filament supported in said bulb, a switch comprising a pair of spaced bimetallic members adapted to be actuated into contact, a heating coil for each of said members with one of the coils being in series with said filament, said members sensitive to their energized coils for flexing in the same direction to maintain separation, whereby the deenergization of said one coil causes said members to contact.

4. In an article of manufacture first and second load elements, a quick make switching mechanism for controlling an energizing circuit for said elements, a fusible link device for holding said mechanism under tension to maintain said first element in said energization circuit, an automatic switch comprising a pair of spaced bimetallic contact members adapted to be actuated into contact, a heating coil for each of said members with one of the coils in series with said first element, said members sensitive to the energization of said coils for flexing in the same direction to maintain separation, whereby the deenergization of said one coil responsive to the disruption of said first element completes an energizing circuit through said members and said fusible link device to cause said mechanism in a quick movement to connect said second element in said energizing circuit.

5. In an evacuated envelope, a pair of spaced bimetallic contact members supported in said envelope adapted to be actuated into contact, a heating coil for each of said members, said members sensitive to their energized coils for flexing in the same direction to maintain separation, whereby the deenergization of one of said coils causes said members to come into contact.

6. In an evacuated bulb, a first bimetallic men her and a second bimetallic member, said members having portions with a relatively small space therebetween and adapted to be actuated into contact, a heating coil for each of the said members, said members sensitive to their energized coils for flexing in the same direction to maintain separation, whereby the deenergization of said coil associated with said first member causes its associated portion to contact the portion ass ciated with said second members.

7. An evacuated envelope, a pair of filaments supported in said envelope, a current supply circuit, switching mechanism arranged to connect the current supply circuit through said filaments in succession, a fusible link for holding said mechanism under spring tension to connect one of said filaments to said current supply circuit, a switching device comprising a pair of spaced bimetallic contact strips supported in said envelope and adapted to be actuated into contact to close a circuit from said current supply circuit through said link, one of said strips responsive to a disrupted filament for closing said contact s rips to disrupt said link, thereby actuating said mechanism to connect another one of said filaments to the said current supply circuit.

8. In an evacuated envelope, a pair of filaments, switching mechanism for controlling the energizing circuits for said filaments, a current controlled holding device for maintaining said mechanism under tension to energize a first one of said filaments, a bimetallic switch comprising a flexible first member and a flexible second mem ber, said members adapted to be actuated into contact to close a circuit through said device, a coil for said first member connected in serie with a first one of said filaments, said first member sensitive to its energized coil for maintaining separation of said members and sensitive to the disruption of the said first filament connected in series with its coil for engaging said second member to close a current path through said holding device, thereby actuating the said switching mechanism for energizing another one of said filaments.

9. In an electric lamp, a pair of filaments, each provided with a terminal contact, mechanism rotatably mounted for supporting said filaments including said contacts, a brush adapted to engage said contacts in succession, a fuse link for holding said mechanism under tension to maintain said brush in engagement with a first one of said filaments, and mean-s for disrupting said fuse link, thereby rotating the said mechanism to establish a current through a second one of said filaments.

10. In an electric lamp, a plurality of filaments, each provided with a contact, a brush, rotatable mechanism for connecting said brush to said contacts in succession, a fuse link for said mechanism to hold one of said contacts in engagement with said brush, a source of current supply, a switch device for closing a circuit through said fuse link to the source of current supply to disrupt the said fuse link, thereby rotating said mechanism for connecting said brush with another one of said contacts.

11. In an article of manufacture, a plurality of circuit elements, switching mechanism pivotally mounted for controlling the energizing circuit for said elements, a fusible link for holding said mechanism under tension, an automatic switch comprising a flexible first contact member and a flexible second contact member disposed with a relatively narrow space therebetween and adapted to be actuated into contact to close an energizing circuit through said link, means for moving said first member away from said second member, and

for moving said second member toward said first member responsive to the energization of one of said elements, and means for moving said first member into engagement with said second member responsive to the disruption of the said energized element to rotate said mechanism for energizing another one of said elements.

12. In an evacuated envelope, a pair of filaments, switching mechanism for controlling the energizing circuit for said filaments, an automatic Switch comprising a pair of spaced bimetallic strips adapted to be actuated into contact, a heating coil for each of said strips, said coil for said first strip connected in series with one of said filaments, said strips sensitive to heat developed by their energized coils for fleXing in same direction to maintain separation, said first strip sensitive to the disruption of the said filament connected in series with its coil for moving into engagement with said strip to thereby actuate the said switching mechanism for energizing another one of said filaments.

13. In an electrical lamp, a pair of filaments, each provided with terminal contact, a source of current, switching mechanism rotatably mounted for supporting said filaments including said contacts, a brush for connecting the source of cur rent to said contacts in succession, a fuse link for holding said mechanism under tension to maintain aid brush in engagement with one of said contacts, an automatic switch comprising first and second bimetallic strips adapted to close a circuit from the source of current through said link, a heating coil for the first contact strip connected in parallel to the source of current, said first strip being sensitive to its energized coil for flexing toward the second strip, another heating coil for the second strip connected in series with one of the said filaments, said second strip being sensitive to its energized coil for flexing away from the first strip, and upon deener ization of its coil for flexing toward the first strip to close a circuit through the fuse link to the source of current, thereby disrupting the said link to rotate said mechanism for connecting'a second one of said contacts to the source of current.

JOHN H. HOMRIGHOUS.

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