EXTENDED LIFE, DOUBLE COIL INCANDESCENT LAMP
First Claim
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1. An incandescent lamp comprising:
- a gas filled glass bulb sealed at its lower end to the flare of a stem press glass mount;
a screw base, having a center contact, attached to the lower end of said bulb;
two lead-in wires extending through the stem press of said mount, one of said lead-in wires being electrically connected to said center contact and the other being electrically connected to the rim of said screw base;
a coiled tungsten wire filament disposed within said bulb and electrically connected between said two lead-in wires;
an inrush current limiting refractory metal wire coil in series with said filament and a thermal switch in parallel with said wire coil, said switch operative to electrically short out said wire coil upon attainment thereof of a predetermined elevated temperature and to maintain said wire coil shorted out during lamp operation.
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Abstract
An electric incandescent lamp has a refractory metal wire coil in series with the lamp filament in order to limit inrush current to the filament. After a short period of lamp operation, a bimetallic switch shorts out the wire coil.
163 Citations
5 Claims
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1. An incandescent lamp comprising:
- a gas filled glass bulb sealed at its lower end to the flare of a stem press glass mount;
a screw base, having a center contact, attached to the lower end of said bulb;
two lead-in wires extending through the stem press of said mount, one of said lead-in wires being electrically connected to said center contact and the other being electrically connected to the rim of said screw base;
a coiled tungsten wire filament disposed within said bulb and electrically connected between said two lead-in wires;
an inrush current limiting refractory metal wire coil in series with said filament and a thermal switch in parallel with said wire coil, said switch operative to electrically short out said wire coil upon attainment thereof of a predetermined elevated temperature and to maintain said wire coil shorted out during lamp operation.
- a gas filled glass bulb sealed at its lower end to the flare of a stem press glass mount;
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2. The lamp of claim 1 including means to heat said switch to said predetermined elevated temperature.
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3. The lamp of claim 1 wherein said switch is normally open when the incandescent lamp is unenergized.
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4. The lamp of claim 3 including means to maintain said switch closed after activation thereof.
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5. The lamp of claim 1 wherein said wire coil is proximate said switch in order to heat said switch to its operative temperature within a few seconds after lamp energization.
Specification
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Current AssigneeEdmund M. Passmore, Warren A. Anderson, William M. Labadini
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Original AssigneeEdmund M. Passmore, Warren A. Anderson, William M. Labadini
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InventorsAnderson, Warren A., Labadini, William M., Passmore, Edmund M.
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Primary Examiner(s)Borchelt, Archie R.
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Assistant Examiner(s)Chatmon, Jr., Saxfield
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Application NumberUS05/410,878Time in Patent Office428 DaysField of Search313/341,316 315/46,47,49,50,67,73,74,100,104US Class Current315/49CPC Class CodesH01K 1/62 One or more circuit element...
