US 4,059,389 A · Photoflash lamp and method of making same

Abstract

A high-voltage type photoflash lamp filled with a filamentary combustible material and oxygen and having a beadless ignition structure comprising a pair of spaced apart lead-in wires with spherically shaped terminations, a glass frit coating over the lead-in wires with scraped-off portions exposing the bare metal of the wire adjacent each termination, and a coating of primer material over the frit-coated terminations and bared portions of the wires. The primer may bridge the wire terminations or comprise separate spaced apart coatings on the respective terminations, with the filamentary combustible being in contact with both terminations to provide a conducting path therebetween. The frit coating is thick enough to prevent preignition short circuits. Also disclosed is a method of making the lamp including the steps of applying a flame to melt down the ends of the lead-in wires to provide smooth and rounded terminations, dipping the wires in a liquid suspension of glass frit, air drying, passing a blade between the wires to scrape away portions of the frit coating and expose bare wire adjacent the terminations, sealing the lead-in wires into one end of a length of glass tubing, dipping the coated lead-in wires into a primer cup to provide a coat of primer over the terminations and scraped portions, and then finishing the lamp.

Claims37

Dependent claims

A photoflash lamp comprising:

an hermetically sealed, light-transmitting envelope;
a quantity of filamentary combustible material located within said envelope;
a combustion supporting gas in said envelope;
and ignition means disposed in said envelope in operative relationship with respect to said filamentary combustible material, said ignition means including a pair of lead-in wires sealed through and extending inside said envelope in a spaced apart relationship, the termination of each of said lead-in wires within said envelope having a smooth and rounded configuration of larger diameter than the remainder of the wire, an insulating material coated on substantially the full length within said envelope of at least one of said lead-in wires for preventing preignition short circuits through said filamentary combustible material, and primer material coated about the smooth and rounded terminations of said lead-in wires, the primer coating on the insulatingly coated lead-in wire being disposed over said coating of insulating material.

1 more element

A method of making a photoflash lamp comprising:

applying a flame to the ends of a pair of spaced apart metal lead-in wires to cause said ends of the wire to melt and provide smooth and rounded terminations;
dipping said lead-in wires in a liquid suspension of glass frit, comprising a fine glass powder blended with a binder, so as to coat said terminations and portions of the wires adjacent thereto;
air drying said frit-coated wires;
sealing said lead-in wires into one end of a length of glass tubing so that only frit-coated portions of the wires extend from the seal to within the tubing, whereby said terminations are supported in a spaced apart relationship within said tubing;
dipping the end portions of said frit-coated lead-in wires into a primer cup so as to apply a coating of primer material about said wire terminations;
filling said glass tubing with a quantity of filamentary combustible material and a combustion-supporting gas;
tipping off the tubing to provide an hermetically sealed envelope;
and
applying a protective coating on the exterior of said envelope.

6 more elements

Dependencies are inferred from the claim text.

Photoflash lamp and method of making same

Life of this patent

Photoflash lamp and method of making same

Life of this patent

Abstract

Claims37