Propagation Primer

Abstract

A propagation primer containing a primer charge having a composition comprising, by weight, approximately: 40-60 percent of barium nitrate 10-20 percent of an aluminum-magnesium alloy 5-20 percent of lead dioxide 6-10 percent of zirconium hydride, and 1-5 percent of boron The composition is substantially insensitive to friction and shock. For propagation over larger distances, additional specific primer compositions may be employed.

Description

BACKGROUND OF THE INVENTION

This invention relates to a propagation primer. More particularly, it relates to propagation primers which are insensitive to friction and shock and which contain a primer charge of particular constituents and/or particular primer compositions.

For use in priming systems, particularly those of the military type, propagation or transmission primers are known having a primer composition containing up to about 60 percent by weight and more of an explosive. These primers, also called flash or flame primers, serve for the transfer or transmission of an ignition impulse, optionally with simultaneous boosting, over a more or less long distance. The operation of such primers involves ignition on one side, called the igniting side, by a flame arriving at said side and then the emission by the primer itself of a flame on the other side, called the firing side, whereby a further ignition is triggered by means of the latter flame at a certain distance. Thus, the provision can be made, for example, in the case of aircraft or missiles, to ignite a propagation primer by means of a conventional perforating, percussion or electrical primer provided at the head of the aircraft, the propagation primer then, in turn, emitting a flame and igniting, for example, through a tube or the like, a further detonation-triggering primer element disposed at a detonator, an explosive charge, or the like, provided in the center or also at the end of the aircraft. Such a provision is made because the primer element is too far apart from the conventional primer to be ignited directly thereby.

For certain purposes, it is required that the device provided for transmitting the ignition flash be most extensively insensitive against outside influences, i.e., it should not become effective unintentionally or inadvertently by mechanical effects, such as impacts, shocks, or the like. In connection with propagation charges, the propagation primer must thus exhibit a shock and friction sensitivity which is lower than that of the propagation charge. Since compact bodies of tetryl (trinitrophenylmethylnitramine) or penthrite (pentaerythrite tetranitrate) are usually employed in the art as the propagation charge, there is hence the requirement for the propagation primers that the sensitivity to shock and friction be lower than that of the substances tetryl and penthrite.

One of the objects of the present invention is to provide a propagation primer having properties and advantages superior to those of the prior art.

Another object of the present invention is to provide a propagation primer which is extremely insensitive to friction and shock.

A further object of the invention is to provide primer charges and primer compositions which can be used advantageously in primers used for the transmission of an ignition impulse over a more or less long distance.

A still further object of the invention is to provide advantageous propagation primers which may be manufactured readily.

These and other objects and advantages of the present invention will become apparent to those skilled in the art from a consideration of the following specification and claims.

SUMMARY OF THE INVENTION

In accordance with the present invention, it has been found that the above advantages and requirements are met by a primer containing a primer charge consisting essentially of, by weight, about:

a. 40-60% of barium nitrate, 10-20% of an aluminum-magnesium alloy, 5-20% of lead dioxide, 6-10% of zirconium hydride, and 1-5% of boron;

and/or a primer charge consisting essentially of, by weight, either approximately:

b.sub.1. 40-60% of barium nitrate, 13-25% of calcium silicide, 10-20% of lead dioxide, 8-14% of an aluminum-magnesium alloy, as well as optionally an addition of about 1-6% of boron;

or approximately:

b.sub.2. 25-45% of lead tricinate (lead trinitroresorcinate) 3-10% of nitroguanidine, 25-45% of barium nitrate, and 8-25% of calcium silicide.

When accommodated in a metallic part dammed up toward the igniting side, or in a correspondingly constructed primer case or cup, the first-mentioned primer charge composition a satisfactorily ignites propellant charges, as well as pyrotechnical mixtures, over short distances. If propagation is to be executed over larger distances, then the first-mentioned primer charge mixture a is suitably maintained as the initial igniting composition, but as the propagation charge, there is employed one of the two additionally mentioned primer charge mixtures b.sub.1 or b.sub.2, depending on the particular requirements involved. The addition of boron mentioned in connection with the primer charge composition b.sub.1 is employed for reinforcing the initial ignition. For the propagation of the ignition over a distance of about 30- 120 cm., perhaps through a narrow tube, the utilization of an explosive cannot be avoided. Thus, in this case, the primer composition b.sub.2 is suitable. In the latter case, it may well be advisable, although it is not always necessary, to employ in conjunction with this primer charge composition also the primer charge composition a . As for the geometric arrangement of the mixture, the same requirements and considerations are applicable as in the utilization of a composition mixture which is free of explosives.

All primer composition mixtures wherein the individual components are employed in quantities ranging within the above-stated limits are substantially less sensitive against shock and friction than the conventional primer charges, and they are also less sensitive than tetryl and penthrite. In this connection, the shock sensitivity thereof is between 0.6 and 1.5 mkp. (meters.sup.. kilopond), depending upon the ratios in which the individual composition components are employed within the above-mentioned permissible limits. The friction sensitivity of all the compositions in accordance with the present invention is above 30 kp. load, as measured in the friction apparatus according to Rathsburg.

BRIEF DESCRIPTION OF THE DRAWING

The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawing which is given by way of illustration only and thus is not limiting of the present invention and wherein,

FIG. 1 shows a primer with an igniting charge and a subsequent firing element;

FIG. 2 shows a primer having a booster charge interposed; and

FIG. 3 shows a schematic view of an ignition chain or sequence.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, wherein like reference numerals are used throughout the various figures to designate like parts, embodiments for propagation primers with the use of a primer charge in accordance with the present invention are illustrated.

The igniting composition 3 and the firing charge 4 are disposed one behind the other in the primer case 1, which latter is open on both ends and is made of, for example, a metal such as brass. The firing charge is covered by a thick foil or the like. The opening in the primer case on the igniting side is provided with the funnel-shaped widened section 2. A flame arriving in the direction of the upper arrow ignites the igniting charge 3 which, in turn, ignites the igniting charge 3 which, in turn, ignites the firing charge 4 and sends, after destroying the cover, an igniting flame in the direction of the lower arrow.

According to FIG. 2, the booster charge 5 is disposed in the primer case 1, provided with an annular flange, between the igniting charge 3 and the firing charge 4. The firing charge is again covered by a foil or the like, and the opening on the igniting side is again provided with the funnellike widened section 2. The propagation primer provided for bridging a distance of, for example, more than 200 mm., is again ignited by a flame arriving at the igniting side. The igniting charge 3 then ignites the booster charge 5, and the latter ignites the firing charge 4, with a simultaneous reinforcement of the ignition jet being sent out by the firing charge. The booster charge, shielded by the igniting charge 3, the firing charge 4 and the case 1 can, in this embodiment, be provided with an explosive without incurring any disadvantages.

In the ignition chain of FIG. 3, the primer element 7 is provided in the igniter (detonator) 6, which primer element can be, for example, a conventional perforation (pin-actuated) primer or a percussion primer or, also, a likewise known electrical primer. After being triggered, this primer element ignites, by means of its ignition flame sent out in the direction of the arrow, the propagation primer 9a disposed at the upper end of the tube 8 and provided with the primer composition of the present invention. The propagation primer 9a effects the ignition of the identical propagation primer 9b disposed in the center of the tube. Finally, the ignition is propagated from the latter primer 9b to the propagation primer 9c provided at the lower end of the tube, which primer is likewise identical with the primers 9a and 9b . This ignition chain can be made as long as desired. In this connection, the spacing between the propagation primers depends, of course, on the particular primer charge employed. At the front end of the ignition chain there is then provided a primer element which, in turn, ignites an explosive charge or the like.

It has been found that an especially advantageous primer charge composition a is the following:

60 percent of barium nitrate

15 percent of an aluminum-magnesium alloy

12 percent of lead dioxide

10 percent of zirconium hydride, and

3 percent of boron.

Other preferred compositions include, for example, a propagation system containing a primer charge b.sub.1 disposed on the firing side and comprising:

50 percent of barium nitrate

20 percent of calcium silicide

15 percent of lead dioxide

12 percent of an aluminum-magnesium alloy, and

3 percent of boron

or a propagation primer containing a primer charge b.sub.2 having the following composition:

30 percent of lead tricinate

5 percent of nitroguanidine

45 percent of barium nitrate, and

20 percent of calcium silicide

The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included herein.

Claims

We claim:

1. A propagation primer composition substantially insensitive to friction and shock comprising, by weight, approximately:

40- 60 percent of barium nitrate

10- 20 percent of an aluminum-magnesium alloy

5- 20 percent of lead dioxide

6- 10 percent of zirconium hydride, and

1- 5 percent of boron.

2. A propagation primer composition substantially insensitive to friction and shock comprising a first primer charge having a composition comprising, by weight, approximately:

40-60 percent of barium nitrate

10- 20 percent of an aluminum-magnesium alloy

5- 20 percent of lead dioxide

6- 10 percent of zirconium hydride, and

1- 5 percent of boron

contiguous to a second primer charge having a composition comprising, by weight, approximately:

40- 60 percent of barium nitrate

13- 25 percent of calcium silicide

10-20 percent of lead dioxide

8- 14 percent of an aluminum-magnesium alloy and, if desired,

1- 6 percent of boron.

3. A propagation primer composition substantially insensitive to friction and shock comprising a first primer charge having a composition comprising, by weight, approximately:

40-60 percent of barium nitrate

10- 20 percent of an aluminum-magnesium alloy

5- 20 percent of lead dioxide

6- 10 percent of zirconium hydride, and

1- 5 percent of boron

contiguous to a second primer charge having a composition comprising, by weight, approximately:

25- 45 percent of lead tricinate

3- 10 percent of nitroguanidine

24- 45 percent of barium nitrate, and

8- 25 percent of calcium silicide.

4. A propagation primer composition substantially insensitive to friction and shock comprising a first primer charge having a composition comprising, by weight, approximately:

40- 60 percent of barium nitrate

10- 20 percent of an aluminum-magnesium alloy

5- 20 percent of lead dioxide

6- 10 percent of zirconium hydride, and

1- 5 percent of boron

contiguous to a second primer charge having a composition comprising, by weight, approximately:

50 percent of barium nitrate

20 percent of calcium silicide

15 percent of lead dioxide

12 percent of an aluminum-magnesium alloy, and

3 percent of boron.

5. A propagation primer composition substantially insensitive to friction and shock comprising a first primer charge having a composition comprising, by weight, approximately:

40- 60 percent of barium nitrate

10- 20 percent of an aluminum-magnesium alloy

5- 20 percent of lead dioxide

6- 10 percent of zirconium hydride, and

1- 5 percent of boron

contiguous to a second primer charge having a composition comprising, by weight, approximately:

30percent of lead tricinate

5 percent of nitroguanidine

45 percent of barium nitrate, and

20 percent of calcium silicide.

6. A propagation primer composition substantially insensitive to friction and shock comprising, by weight, approximately:

40- 60 percent of barium nitrate

13- 25 percent of calcium silicide

10- 20 percent of lead dioxide

8- 14 percent of an aluminum-magnesium alloy and, if desired,

1- 6 percent of boron.

7. A propagation primer composition substantially insensitive to friction and shock comprising, by weight, approximately:

25- 45 percent of lead tricinate

3- 10 percent of nitroguanidine

24- 54 percent of barium nitrate, and

8- 25 percent of calcium silicide.

8. A propagation primer composition substantially insensitive to friction and shock consisting of, by weight, approximately:

50 percent of barium nitrate

20 percent of calcium silicide

15 percent of lead dioxide

12 percent of an aluminum-magnesium alloy, and

3 percent of boron.

9. A propagation primer composition substantially insensitive to friction and shock consisting of, by weight, approximately:

30 percent of lead tricinate

5 percent of nitroguanidine

45 percent of barium nitrate, and

20 percent of calcium silicide.

10. A propagation primer composition substantially insensitive to friction and shock consisting of, by weight, approximately:

60 percent of barium nitrate

15 percent of an aluminum-magnesium alloy

12 percent of lead dioxide

10 percent of zirconium hydride, and

3 percent of boron.