US2270162A - Photoflash lamp - Google Patents

Description

Jan. 13, 1942.

v 55 ATTORNEY PHOTOFLASH LAMP Filed Jan. 26, 1940 M. J. N. DE MARGITTA Patented Jan. 13, 1942 UNITED STATES PATENT 'OFFICE PHOTOFLASH Michael J. Neumann de Margitta, New York,

N. Y., assigner to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application January 26, V1940, Serial No. 315,739

- In Hungary September 5, 1939 10 Claims.

The invention relates to lamps, and especially to photoflash lamps.

An object of the invention is to provide a cheap and easily manufactured photoash lamp.

Another object of the invention is to provide a method of assembling photoilash lamps for quantity production. n

Other objects and advantages of the invention will be apparent from the following description and drawing, in which:

Fig. 1 is a cross-section through a preferred embodiment of the invention.

Fig. 2 is a modification of the embodiment in Fig. 1.

Figs. 3 and 4 are cross-sectional views of a 'l 2g 24 therethrough, for the application of a heatpreferred type of mold for forming one end of the flashlamp having conductors sealed therein.

Figs. and 6 are cross-sections through a preferred type of mold for forming the other end of the lamp.

Fig. '7 is a cross-sectional view on linesVII- VII of Fig. 4. X

The present commercial type of photoilash lamp has glass casings which have to be carer fully handled, formed and sealed with a resultant price which is high in comparison with the cost of the filament. I

Furthermore, these gl'ass case ilashlamps always present a possible danger of Vbroken glass, especially in 'the disposal of them. It 1s one oi the objects of my invention to provide a photoash lamp having a casing in which there will be no danger of broken glass from handling, use or disposal, and also one that can be very easily and cheaply manufactured, as illustrated on the drawing, and described below.

In Fig. 1 I have illustrated a preferred type of photoflash lamp having two conductors Il and II therein, with van igniting element I2, such as a filament coated with zirconium, aluminum or phosphorous powder, and a lling of combustible material I3, such as a foil,V or a bundle of line wires of aluminum or magnesium. The casing I4 in my preferred embodiment, isv an integral piece of plastic material. These plastic materials comprise the group of cellulose acetates. phenol-formaldehyde and urea-formaldehyde resins, casein, pyroxylin, shellac, rubber, acryl and vinyl compounds having a' translucency or transparency suitable for the passing of light material because it is tough, hard to burn and can stand careless handling. I do not prefer .the cellulose that has to be constantly protected' by a special casing except when actually made ready for use.

In Fig. 3 I have illustrated the rst step in the preferred preparation of my flashlamp. A twopart mold is disclosed in which the upper part I5 has a cylindrical opening I6 of the desired outside diameter of the photoflash lamp extending therethrough, except that the lower portion I1 of the cylindrical hole I6,-is gently tapered to the desired contour of the lower portion of the lamp. The very bottom portion of the lamp.- however, isformed by the contour I8 in the upper portion of the lower mold I9. The lower mold I9has two centrally located openings 20 and 2| for the passage of the conductors 22 and 23 into the space I 6. The lower mold has passageways ing medium, which is preferably steam, although other forms of heating energy might be supplied to the lower mold. The upper mold has passageways 25 therethrough, especially .for a cooling g5 liquid such as water, although at other times $0 plastic material 26, such as cellulose acetate, is

inserted in the upper mold. This plastic material may be conveniently inserted in the form o! a-hollow tube with an outside diameter to fit in the hole I6, and thus substantially coincide with the desired diameter of the completed ashlamp. A forming member 21 is now inserted into the central portion of the opening I6. This forming member 21' has a shape and diameter corresponding tothe shape and inner diameter of the completed ilashlamp. In the center of this forming member are two holes 28 and 29 for the purpose of holding the conductors 22 and 23 in position while the lower end of the ilashlamp is being formed. The bottom portion 28' and 29" f 5 of these holes are slightly enlarged to guide the conductors into the. openings when the inner member 21 is lowered. This member 21 is low-v ered the distance (a), illustrated in Fig. 3, and then lthe two conductors 22 and 23 are pushed up i'nto these holes 22 and 29, as illustrated in Fig. 4.

Steam is then admitted into the passageways 24, so that thelower mold Il becomes very hot. At the sametime, a sleeve 29 is lowered around the forming member 21 and presses upon the uptherethrough. Cellulose acetate is my preferred 65 per end 3l of the cylindrical Plastic tube S0 that its lower edge 32 is pressed downward into the ,heated space I8 at the top of the lower mold I9.

able pressure is exerted on the plastic material to completely ll this space by the sleeve 3U which fills the clearance space between the inner forming member 21 and the outer diameter of the opening I8 in the upper mold. This sleeve presses down the plastic tube the distance (c) illustrated in Fig. 4.

The slight clearance between the conductors 22 and 23 and the rim of the openings 3l) and 2l permits the escape of the imprisoned air, but this clearance is not sufficient to allow the plastic material to flow therein.

The steam is then shut off andcooling material sent through the passageways 25 in the upper mold I5, and also preferably through passageways 34 in the inner forming member 21. The plastic material 26 under the in duence of this cooling means through 25 and 34, hardens into a closed end tube sealed about the conduc-, tors 2B and 29. The lower mold I9 is removed, and the inner forming member 21 and sleeve 3D raised and the partially formed closed end tube 26, with its conductors sealed therethrough, removed from the upper mold I by pressing upon the newly formed projecting portion 33, illustrated in Fig. 4.

An alternative method is to place or pour softened plastic material between the heated surfaces of the former and mold members of Fig. 4 and, after pressing into shape, to cool and remove the tube and conductors sealed therethrough.

A combustible material I3 is inserted in this tube and the igniting means I2 connected across the topportion of the conductors. If desired, a thermal shield 34, such as an asbestos disc or mica disc, may be secured to the top of the conductors. The appearance oi' the tube is now that of Fig. l except that the top portion of the container I4 is that illustrated in dotted lines. 'Ihe tube is then preferably inserted in theV apparatus illustrated in Fig. 5, with the open end 35 of the tube facing downward in an upper mold 36. The central opening 31 of the mold, in which this tube has been inserted, has a curved bottom portion 38 corresponding to the desired'shape oiA the top portion of the tube, except for the very top portion whose contour 39 is made' in the lower mold 40.

Aside opening I4I in the upper mold 36 extends Fs' to a two-way valve opening to an exhaust port 42 and also to an oxygen or other active gas Asupply port 43. The upper mold 36 contains passageways 44 therethrough for a cooling liquid,l

such as water. and the lower mold 40 has passageways 45 therethrough, for a heating medium whichfin this case, is that of .an electric ,heater oxygen supply is passed in by means of the port 43 to fill the inner portion of the container to any desired pressure of below, at, or above atmospheric pressure.

The heating means at 45 of the tube becomes soft because of the presin the lower mold is). then actuated and the tube pressed downward sure and heat. The softened plastic is then shaped by the hot walls of the mold into a closed end`46, illustrated in Fig. 6. The heating medium in is shut off and a cooling medium In Fig. 2 I have illustrated a modification in which the lower portion of the lamp 41 is molded as the screw-threaded base with a central conductor 48 extending therethrough. Asbestos or mica discs 50 and 5I help support these conductors in the tube with the combustible material I3 around them. A conductive metal coating 52 is then sprayed over the screw mold 49 down to the portion 53 where the wireY 49 extends through the casing.

Fig. 2 illustrates a very cheaply formed screw-l threaded type of flashlamp.

Although I have described certain embodiments and also certain steps in the manufacture of these embodiments, it is apparent that many modifications and changes in the form of the vdevice and in the steps oi' manufacture can be made. Accordingly, I desire only such limitations on my invention as are necessitated by the spirit and scope of the following claims.

I claim:

1. The method of making a fiashlamp which comprises inserting a plastic material in a mold, placing conductors therein, applying heat to the plastic material, pressing the plastic material into a closed end tube about said conductors, inserting igniting means across said conductors and combustible material in said tube. exhausting the tube, filling the tube with a combustion-supporting gas, and sealing the open end ofthe tube.

2. 'I'he method of making a ashlamp which comprises inserting a plastic material in a mold, placing conductors therein, applying heat to the plastic material, pressing the plastic material into igniting means across said conductors and combustible material in said tube, exhausting the tube, lling the tube with a combustion-'supporting gas at more than atmospheric pressure, and sealing the open end of the tube.

3. The method of making a 'flashlamp which comprises inserting conductors in an open end of a tube of plastic material, heating said open end of plastic material to flow about said conductors and be sealed thereto to form a closed end tube, connecting igniting means to said conductors, placing combustible material in said tube, inserting a combustion-supporting gas in said tube -and sealing the open end of said tube.

4. The method of making a flashlamp which comprises inserting a tube of plastic material in a mold. locating conductors at one open end oi' said tube, applying heat to the region of said conductors, pressing said tube into said heated region to seal the plastic material into a closed `end tube about said conductors, connecting an igniting deviceto said conductors within the tube, placing combustible material around the igniting device. and sealing the open end of the tube.

`5. The method of making a flashlamp which comprises placing a tube of plastic material in a cylindrical mold. locating conductors in the bottomyof said mold, applying heat to the bottom portion of said mold and pressing downward on said tube to mold said plastic material about said conductors, connecting an igniting device to said mosphere from said tube and replacing it with a d combustion-supporting gas, heatingthe end ofconductors within said tube, placing combustible material about said igniting device and sealing the open end of said tube.

6. The method'of making a ilashlamp which comprises placing a tube of plastic material in a cylindrical mold, inserting a former within said tube, holding conductors by said former, applying heat to said tube to mold one end of the tube into a closed end tube between the mold and former and sealing'the conductors through said closed end, connecting an igniting means to said conductors within the tube, surrounding the igniting means with a combustible material and sealing the open end of said tube.

7. The method of making a ashlamp which comprises placing a tube of plastic material in a cylindrical mold, having the desired contour of the outside of one end of the lashlamp, inserting a former having the desired contourof the inside of one end of the ashlamp, holding conductors extending through said former and mold, applying heat and pressure to said tube to form a closed end of the tube between the mold and former and sealing the conductors therethrough,

said tube and sealing the open end thereof in said mold.

9. The method of making a ilashlamp which comprises sealing conductors through the closed end of a tube of plastic material, connecting an igniting device to s aid conductors within said tube, placing combustible material about the igniting device, inserting the open end of said tube' within a tight-tting mold; exhausting the atmosphere from said tube and replacing it with a combustion-supporting gas at greater than atmospheric pressure, heating the end of said tube, and sealing the open end thereof in said mold.

10. The method of making a flashlamp which lcomprises placing a tube of plastic material in a cylindrical mold having the desired contour of the outside of one end of the flashlamp, inserting a former having the desired contour of the inside of one end of lthe ashlamp, holding conductors extending through said former and mold, applying heat and pressure to said tube to form a closed end of the tube between the mold and formersealing the conductors therethrough, removing the former and then the tube from the mold, connecting an igniting device to said conductors within the tube, placing combustible material about said igniting device and sealing the other end of said tube by inserting vthe end in a tight-tting mold, heating the plastic edge until.

it shapes into a closed end conforming to the contour of the mold, hardening the tubev and withdrawing it from the mold.

MICHAEL J. NEUMANN DE MARGITIA.

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