Pyrotechnic Assembly

Abstract

A pyrotechnic assembly including a safety device to prevent the ignition of the main pyrotechnic load until the load has been completely expelled from an associated launch tube. The safety device is biased to operate only upon the explosive launch of the load from the launch tube.

Description

BACKGROUND OF THE INVENTION

In pyrotechnic and explosive assemblies in which a flare decoy or other pyrotechnic material is launched from a tube, it is imperative that a safety device be present to prevent the premature ignition of the pyrotechnic material before it is expelled from the tube. While many devices such as pull ignitors and complex acceleration devices have been employed for this purpose, all have the disadvantage of being not entirely fail-safe and they are oftentimes unduly complex and difficult to produce and/or assemble.

SUMMARY OF THE INVENTION

The invention comprises a pyrotechnic assembly in which the load of pyrotechnic material is separated from its launching charge by a piston member and a base member having a biased ignitor member. The biased ignitor member is lit by the launching charge and will ignite the pyrotechnic material once the round has cleared its associated launch tube.

Therefore, it is an object of the invention to provide a pyrotechnic assembly which includes a safety device to prevent the ignition of the main pyrotechnic load without the explosive launch of the load from an associated launch tube.

Another object of the invention is to provide a safety device for a pyrotechnic assembly which is simple, inexpensive and easy to manufacture and assemble.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a pyrotechnic assembly of the present invention.

FIG. 2 is a sectional view of the pyrotechnic assembly of FIG. 1 taken along line 2-2.

FIG. 3 is a partial sectional view of the pyrotechnic assembly of FIGS. 1 and 2 illustrating ignition of the load of pyrotechnic material immediately following its launch from the associated tube.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

As illustrated in FIG. 2, the pyrotechnic assembly 10 includes a launch tube 12 of polyethylene or other suitable structural material which encloses the remainder of the pyrotechnic assembly 10. A pyrotechnic round 14 is contained within the launch tube 12 at one end thereof. The pyrotechnic round 14 includes a load of pyrotechnic material 16 supported upon a base 18 of structural material such as steel. The pyrotechnic material 16 may consist of an illuminating flare material, high-energy radiating particles, infrared radiating material, infrared radiating flash pellets, electromagnetic wave reflective material, other similar material or combinations of the above. The load of pyrotechnic material 16 may be physically connected to the base member 18 by means of a suitable device such as the fastener 20 which may be a wood screw or metal rod. Also, the interior of the pyrotechnic material 16 adjacent to the base member may be filled with gun powder or other explosive substances. A thin wall pyrotechnic tube 22 may be necessary to enclose the load of pyrotechnic material 16 if the pyrotechnic material 16 is not capable of supporting itself. Since, however, the pyrotechnic material 16 will in most instances be highly compacted, it can be utilized without a supporting tube 22. If, however, the tube 22 is utilized, an opening 23 must be provided in line with the pivotally mounted biased ignitor member 26. The open end of the pyrotechnic tube 22 may be closed by a plastic end cap 24.

The biased ignitor member 26 is positioned on the opposite side of the base member from the pyrotechnic material 16. As illustrated, this member 26 may comprise a cylindrical cup 28 of pyrotechnic ignition material 30 supported by a spring 32 mounted upon a spring rod 34 positioned in the base member 18. A piston member 36 is provided adjacent to the biased ignitor member 26 of the base member 18 and holds the closed end of the ignitor cup 28 against the base member 18. A small opening 38 through the piston member 36 is aligned with the ignition material 30 in the cup 28 to provide communication to the opposite side of the piston member 36. The piston member 36 may be a single plate or two separate plates physically attached by cement to align the respective holes therethrough.

The pyrotechnic round expulsion assembly 40 is provided on the opposite side of the piston member 36 from the ignitor member 26. The assembly 40 includes a squib 42 and squib 42 and squib retainer 44. Round expulsion assembly 40 is held in the launch tube 12 by an end plate 46 and may be electrically actuated by wires 48. The squib is aligned with the opening 38 in the piston member 36.

The pyrotechnic round 14 is first assembled and inserted into the launch tube 12 after which the piston member 36 and the round expulsion assembly 40 are inserted.

In operation, the squib 42 is actuated to simultaneously accomplish two things: First, to assert a force upon the piston member 36 so as to expel the piston member 36 and the pyrotechnic round 14 from the launch tube 12 and second, to ignite the ignition material 30 in the ignitor cup 28 with the hot gases and fire from the squib 42 which have proceeded through the opening 38 in the piston member 36. As shown in FIG. 3, once the pyrotechnic round 14 has cleared the launch tube 12, the biased spring 32 will act upon the cup 28 containing the ignited material 30 and pivotally rotate the cup 28 so that the ignited material 30 will contact the pyrotechnic material 16 of the pyrotechnic round 14 thereby igniting the pyrotechnic material 16. If the pyrotechnic tube 22 is utilized to support the pyrotechnic material 16, the cup 28 will contact the pyrotechnic material 16 through the opening 23.

In this manner it can be seen that the pyrotechnic material 16 cannot be ignited unless and until the squib 42 has been ignited to expel the pyrotechnic round 12 from the launch tube and simultaneously ignite the ignition material 30 in the cup 28. Accordingly, the pyrotechnic assembly is not susceptible to premature ignition from acceleration forces or rough handling. If the pyrotechnic round 14 is expelled from the launch tube 12 by any means other than by the explosive force of the squib, the pyrotechnic material 16 cannot be ignited since the ignition material 30 in the cup 28 has not been ignited. Likewise, if the squib 42 only partially ejects the pyrotechnic round 14, the squib will ignite the ignition material 30 in the cup 28 but the launch tube 12 will prevent the ignition material 30 from contacting the pyrotechnic material 16. The base member 18 prevents the direct ignition of the pyrotechnic material 16 from the ignition material 30 in the cup 28 or from the hot gases and fire from the squib 42.

While specific embodiments of the invention have been illustrated and described, modifications and changes can be made thereto without departing from the spirit and scope of the invention and it is intended that the invention be defined in the following claims.

Claims

I claim:

1. A pyrotechnic assembly comprising: a launch tube; a pyrotechnic round positioned within said launch tube, said pyrotechnic round including a load of pyrotechnic material, a base member supporting said load of pyrotechnic material, a spring-holding member mounted on said base member on the opposite side of said base member from said load of pyrotechnic material, a biased spring member pivotally mounted on said spring holding member, one end of said spring member braced against said base member on the opposite side of said base member from said load of pyrotechnic material, a cup fixedly mounted on the other end of said spring member, said cup containing pyrotechnic ignition material; a piston member positioned within said launch tube adjacent said base member, said piston member serving to hold said cup in a cocked position with the closed end of said cup held against said base member on the opposite side of said base member from said load of pyrotechnic material, said piston member having a small opening therethrough communicating with the pyrotechnic ignition material in said cup; and a squib means positioned on the opposite side of said piston member from said cup and aligned with said small opening in said piston member for simultaneously asserting a force on said piston member to expel said piston member and said pyrotechnic round from said launch tube and igniting said pyrotechnic ignition material in said cup through said small opening in said piston member whereby upon expulsion of said pyrotechnic round and said piston member from said launch tube said biased spring member will act upon said cup containing the ignited pyrotechnic ignition material and pivotally rotate said cup up and back so that the ignited pyrotechnic ignition material will contact said load of pyrotechnic material of said pyrotechnic round thereby igniting said load of pyrotechnic round material.

2. The pyrotechnic assembly of claim 1, wherein said cup is cylindrical.

3. The pyrotechnic assembly of claim 1 wherein said squib is electrically actuated.

4. The pyrotechnic assembly of claim 1 wherein said load of pyrotechnic material includes infrared radiating material.

5. The pyrotechnic assembly of claim 1 wherein said load of pyrotechnic material includes illuminating flare material.

6. The pyrotechnic assembly of claim 1 wherein said load of pyrotechnic material includes a plurality of small, high-energy radiating particles.

7. The pyrotechnic assembly of claim 1 wherein said load of pyrotechnic material includes infrared radiating flash pellets.

8. The pyrotechnic assembly of claim 1 wherein said load of pyrotechnic material includes electromagnetic wave reflective material.

9. The pyrotechnic assembly of claim 1, wherein said spring-holding member is a rod.