US2032357A - Pyrotechnic unit - Google Patents

Description

Patented Mar. 3, 1936 PATENT QFFIQ'E PYROTECI-INIC UNIT Max'W. Fischer, Washington, D. 0., and Raymond L. Graumann, Alexandria, Va.

Application October 6, 1932,-Serial No. 636,532 6 Claims. (01. 102 -24) (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) invention relates to a pyrotechnic unit, and more particularly to a moisture proof closure "for such unit for use in aircraft float lights.

It is the object of this invention to provide a pyrotechnic unit thatwill be protected for an indefinite length of. time against penetration of moisture.

' With the above and other objects in View, the invention consists in the construction, combination and arrangement of parts as will be more fully described hereinafter.

The-drawing shows an axial section of one embodiment of our invention.

Aircraft fioat lights are intended to be dropped into water and are provided with wooden bodies to make them sufficiently buoyant to float on the surface thereof. Heretofore, the pyrotechnic material in such lights has been placed in a cavity in the wooden body but it is found that moisture penetrates the wood and impairs the pyrotechnic charge. We have devised an inclosure for such pyrotechnic material that will protect it from moisture under any conditions of humidity and for any length of time.

As shown in the drawing, our invention comprises an elongated metal tube I having a closed end 2. In the open end is a base member 3 havin an externally threaded shank 4 extending from its outer face. The edge of tube I is spun or otherwise upset over the edge of the outer face of base 3, as indicated at 5. A nut B is screwed on shank 4 to clamp edge 5 against base 3 and form a completely water-proof closure. A kerf is formed in the inner face of closed end 2 to weaken the end so that the pressure of gases generated in the tube will readily blow out a portion of the closed end to permit the flame from the pyrotechnic material to pass out into the air and become visible. The shank 4 has in it a seat 8 for a primer to be fired by any of the well known mechanisms used for this purpose and a passage 9 leading inwardly to permit the flame from the primer to ignite a fuse train III that is inserted into the base 3 and extends upwardly through pyrotechnic pellets I I to the igniting mixture I2 in starter cup I3. When our pyrotechnic unit is employed for the use above mentioned, namely, aircraft float lights, the firing pm of the firing mechanism is driven against the primer when a portion of that mechanism impacts the water after the light has been dropped from an aircraft. Longitudinally bored member I6 clamps a thin copper cup I'I that will be indented, but not punctured, by a firing pin, against shoulder I8 0n shank 4 to prevent penetration of moisture around the primer in chamber 8. .A disk I4 -of fiber or other combustible material closes the open end of starter cup I3, the edges of the cup being bent over the outer face of disk I4 in a plurality of places as indicated at I5 to retain the disk in position. 7

When the primer ignites fuse train I0, the train burns upwardly and ignites the mixture in starter cup I3. The cup burns and so propagates the combustion to pellets Ii which burn downwardly through their length. Disk I4 also burns and the gaseous. pressure developed inside tube I blows out that portion of end 2 included within the kerf l and so permits the escape of flaming gases to the air to form a visible light.

The wall of tube I is thin and is made of block tin, which will melt or burn down at the same rate as the pyrotechnic pellets without affecting the time of burning or the character of the resulting signal.

It is obvious that the edge of tube I may be secured to base 3 by soldering or brazing, or in any manner to provide a water-tight joint.

A pyrotechnic charge inclosed as herein disclosed will be protected against moisture for any length of time and consequently will always maintain its activity unless decomposition of the pyrotechnic material occurs due to inherent properties of its composition.

It will be understood thatthe above description and accompanying drawing comprehend only the general and preferred embodiment of our invention, and that various changes in construction, proportion and arrangement of parts may be made within the scope of the appended claims without sacrificing any of the advantages of this invention.

The invention herein described may be manufactured and used by or for the Government of the United States for governmental purposes without the payment of any royalty thereon.

We claim:

1. In a pyrotechnic unit, a base having an externally threaded shank on its outer face, said shank and base having a passage therethrough, an elongated enclosing member having one end closed and the edge of the other end upset against the outer face of said base, said closed end being weakened by a kerf in its inner face, a nut screwed on said shank to clamp said edge against said base, pyrotechnic material in said enclosing member, a starter cup seated on said material at the closed end of said member, a combustible disk in the open end of said cup, portions of the edge of said cup being overturned over said disk,

and a fuse element fitted in the passage through said base, and extending through the pyrotechnic material into said cup.

2 In a pyrotechnic unit, a base having an externally threaded shank on its outer face, said shank and base having a passage therethrough an elongated enclosing member of moisture-proof material closed at one end and having the edge of the other end inturned against the outer face of said base, the closed end of'said member being weakened by a kerf on its inner face, a nut on said shank set tightly against the inturned edge of said member, a starter cup in said member at its closed end, a combustible disk closing said cup, portions of the edge of said cup being turned over said disk, and a cup of readily puncturable metal clamped on said shank to close the outer end of the opening therethrough.

3. A burning pyrotechnic unit comprising an enclosing member of block tin having a closed end and an open end, a closure seated in said open end over which the edge of said member is turned, a clamping element engaged with said closure to clamp said edge against said closure pyrotechnic material in said member and a fuse train extending into said closure and thence throughout the length of said material.

4. A burning pyrotechnic unit comprising an enclosing member of metal adapted to be broken down by fire at the same rate as the pyrotechnic material therein burns, said member having a closed end and an open end, a closure seated in said open end over which the edge of said member is turned, a clamping element engaged with said closure to clamp said edge against said closure pyrotechnic material in said member and a fuse train extending into said closure and thence throughout the length of said material.

5. A burning pyrotechnic unit comprising an enclosing member of block tin having a closed end and an open end, an axially bored closure seated in said open end over which the edge of said member is turned, a clamping element engaged with said closure to clamp said edge against said closure, a thin walled cup of soft metal to close the bore in said member but readily indentable by a firing pin pyrotechnic material in said member and a fuse train extending into said closure and thence throughout the length of said material.

6. A burning pyrotechnic unit comprising an enclosing member of block tin having a closed end and an open end, an axially bored closure seated in said open end over which the edge of said member is turned, a clamping element engaged with said closure to clamp said edge against said closure, a thin walled imperforate cup of soft metal to close the bore in said member, means to clamp said cup to said closure, pyrotechnic material in said member and a fuse train extending into said closure and thence throughout the length of said material.

MAX W. FISCHER. RAYMOND L. GRAUMANN.

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