US1856431A - Electric ignition device - Google Patents

Description

Flgd May 29, 1930 INVENTOR. GUY FROL LANDg ATTORNEY.

llllllicIll:

atented May 3, 1932 GUY E. ROLLAND, OF TAMAQUA, PENNSYLVANIA, ASSIGNOR TO ATLAS POWDER COM- PANY, 0F WILMINGTON, DELAWARE, A CORPORATION 0F DELAWARE ELECTRIC IGNITION DEVICE Application med May 29, 1930. Serial No. 457,022.

This invention relates to certain new and useful improvements in electric ignition devices, commonly known to those versed in the art as electric squibs. Thefunction of commercial electric squibs is to initiate or iire charges of deflagrating or low explosives, such, for example, as granular black powder, pelleted black powder, and the like.

The object of the invention is to provide an electric squib which will have greater water and moisture resistance, greater safety in handling and more positive action in the liring of charges of low explosives than any commercial electric squib known at the present time.

The conventional form of electric squib consists of an electric igniting element around which is formed an inflammable mass or firing composition. The igniting elem-ent and firing composition are usually placed in a paper or metal tube, one end of which is sealed and the other or firing end of which is fitted with one or morevents to allow for the escape of the flash caused by the firing composition. When the vents are on the ends of the tubes, they are usually closed by means of corks or other kinds of Stoppers. However, when metal shells are employed, it has, heretofore, been the practice to it them with one or more side wall vents and without end vents. In such cases, the vents are always left unclosed. In the case of the paper tube type of squib, closed with a stopper to protect it from moisture, manufacturers recommend either that the Stoppers be removed just prior to use or that a notch be cut in the side wall of the paper tube, in order to assure good ignition.

In use, the electric squib is placed in contactwith r in close relation to a charge of low explosive, such as black powder. The iash of the electric squib gives the heat and flame necessary to cause ignition of the charge. Heretofore, an electric squib p'rovided with a paper tube has been generally used. It has been found that this squib, even when fitted with a stopper in its vent hole, is very susceptible to the effects of moisture; to which it may be exposed in storage or prior to use, and, thus, itmay. be rendered entirely worthless for the purpose for which it was intended. In addition to the above mentioned weakness, it has been found that An electric squib made with a metal shell I with one or more vent holes, either in the side wall or bottom, is more rigid than that made with the paper tube and thus it is not as liable to cause a premature explosion. However, it has the same decided defect, common to the paper tube electric squib, in that it is very susceptible to the effects of moisture. This causes electric squibs, embodying metal shells provided with open vents, to function poorly and, in many cases, to misiire, completely.

The present invention overcomesthe above mentioned ditliculties and defects which are inherent in the present types of electric squibs.

I have devised an electric squib which is completely moisture proof, is of sturdy and rigid construction and functions very satisfactorily in the ignition of low explosives, such as black powder, even under the most adverse conditions, while, at the same time, it may be economically manufactured from readily available, easily workable vand inexpensive materials.

This electric squib consists of a closed lnetal shell, preferably of aluminum, containing sealed therein an electric igniting element surrounded by a firing composition, and, in addition, an auxiliary inflammable mass, preferably in pulverulent or granular form, such as black powder, between the flash composition on the igniting element and the bottom of the closed metal shell. When the iguiting element is heated by the passage of an electric current, the heat causes the iash composition on the igniting element to burn with a Hash, and this, in turn, ignites the aum'liary Hash composition and bursts the shell. This produces and discharges a big flame directly into the charge of low explosive, such as black powder, igniting the same in a very positive and certain manner.

I have found that, if the shell is weakened at any particular place by a score or scratch in the metal, it will burst along this weakened line. In view of the fact that I have found it desirable to have the flash of the electric squib emitted from the side of the shell, I prefer to place a furrow, score or scratch, lengthwise, on the lower portion of the shell.

I have also found that, if the shell is not weakened at any particular place by a score or scratch in the metal, it will usually burst .in the lower portion, but sometimes it will burst in the upper portion, the igniting element and sealing composition being blown away from the shell. It should be clearly understood that, even though the flame from the flash composition on the igniting element and the auxiliary flash composition is vented through the upper end of the shell, due to the failure of the lower portion to burst, it will still function in the ignition of low explosives, such as black powder.

In view of the fact that I. have found it desirable to insure that the shell will always burst in the lower portion, regardless of whether or not the shell has been weakened at any particular place by a score or scratch in the metal, I may accomplish this desired effect by placing one or more crimps in the shell at any desirable stage, during the assembly or after the assembly of the electric squib. The shell may be crimped with any suitable type of crimper or rolled to form any suitable type of inside bead in the portion of the shell surrounding the igniting element, or in the portion of the shell above the igniting element. This insures that the aluminum shell, with or without the weakening score or scratch, will always burst in the lower portion and the igniting element and sealing composition cannot be blown away from the shell.

I have found, for instance, that a crimp formed by a loop wire crimper in the portion of the shell surrounding the igniting element functions very satisfactorily .in this respect. However, it should be clearly understood that any form of crimper or beader, or indenter,

- may be used to obtain the desired effect. For

' example, a series of indentations in the shell would serve the same purpose as a continuous crimp or bead in the shell.

I have also found that the igniting element and sealing| composition can be securely held in the shell if the open end of the shell is constricted or turned in, either before or after the igniting element and auxiliary flash composition have been inserted and either before or after the sealing composition has been placed therein.

It should be clearly understood that this electricrsquib may, under favorable conditions, function satisfactorily without the auxiliary inammable mass, without the extra crimping or constriction and without the score in the shell, but that I prefer to employ these features as added safeguards and to insure the ignition of charges vof low explosives, under most adverse conditions.

The fact that this metal electric squib is kept completely closed up to the moment of use, renders it wholly moisture-proof, and thus it is an improvement on, and is superior to all known commercial electric squibs. In addition, since the shell is made of metal, or

' other sturdy material, it is not easily crushed and thus, it is an improvement on, and is superior to electric squibs made with paper tubes.

In the accompanying drawings:

Fig. 1 is a vertical sectional view,

Fig. 2 is a side elevation of one embodiment of the invention,

Fig. 3 is a vertical sectional view of another embodiment Aof the invention,

Fig. 4 is a vertical sectional view of a third embodiment of the invention, and

Fig. 5 is a perspective view illustrating a manner of scoring the shell, which may be em ployed, if desired.

Like numerals designate corresponding parts in all of the figures of the drawing.

Referring to Fig. 1, 5 designates a metallic shell that is closed at its inner end 6, and open at its outer end. This shell is, preferably. provided with a conventional bead 6, within which a sealing plug 7, of tar, sulphur or other well known material, engages. Lead-in wires, indicated at 8 and 9 conduct current to an electric match of conventional form, indicated at 10, and which comprises a match head or flash composition 11. This ignition device is contained within an insulating paper tube 12, said tube being filled with a sealing composition 13, by which the igni-` tion device is held in said paper tube. The

lower portion of the shell 5 contains a body of auxiliary flash composition 14. This may consist of grained black powder, or any other material of a nature adapted to serve the purposes described, and which will produce a with an annular indentation 17, which pre-` vents the ignition assembly from being blown out of the shell. The elements employed, in

conjunction with the structure of Figs.v 3 and 4 are substantially the same as those heretofore described, and the same reference characters have been employed. In all cases, the shell is of such material and thickness that it will be ruptured by the Hash of the composition on the igniting element, or by the combustion of the auxiliary Hash composition, or both.

I have found that an aluminum shell meets this bursting requirement in a highly satisfactory manner, especially when its wall thickness is about .0065, and it is used in conjunction with an auxiliary Hash composition. Aluminum has the further advantage that it is cheap, light and readily drawn into the shell form.

The shell may be made in any desired way. That is to say, it may be made without any crimped portions, or it may be provided with the two crimped portions illustrated in Figs. l and 2, or the lower portion of the shell may be constricted to form a stop for the igniting element, as illustrated in Figs. 3 and 4, the difference between these two figures being that, in Fig. 3, a .distinct indentation or groove is formed to constitute a stop for the ignition element, the lower portion of the shell being of smaller diameter than the upper portion, while, in Fig. 4, the stop for the ignition element consists of a shoulder formed by making the lower portion of the shell of smaller diameter than the upper portion thereof.

In Fig. 5, I have shown a fragmentary inverted view of the shell. wherein the scoring indicated at 16a is extended across the bottom of the shell, at 1Gb, in two directions, so that wh en the squib is fired, the entire lower end of the shell may Hare out, or mushroom and leave a free passage for the large hot flame into the charge to be fired.

While I have made particular reference to aluminum as a material for making these shells, it will be understood that the invention is not restricted thereto. For example, the shell may be made from other metals, such as copper or non-metallic ,materials, such as a Hber composition.

While I have made particular reference to grained black powder as an auxiliary Hash composition, it will be understood that the scope of my invention includes the use of any suitable deiagrating material. I wish it to be understood that by deHagrating material I mean a material which will burn and produce a considerable volume of hot flame for the actual ignition of low explosive charges, in contradistinction to any materials or devices which function by concussion or detonation. v

It is to be understood that the invention inclu des within its purview whatever changes fairly come within either the terms or the spirit of the appended claims.

Having claim is:

1. A device of the character described, comprising a closed metallic shell, an electric ignition means therein, a Hring composition ignited by said ignition means, an auxiliary deflagrating Hash composition in the inner end of the shell adapted to ignite a charge of low explosive by the Hame produced thereby, and means for weakening the lower portion of the shell to insure its rupture upon the ignition of the contents thereof.

2. An electric squib comprising a closed shell, an electric igniting element surrounded by a Hash composition and an auxiliary delagrating Hash composition in the portion of the closed shell between the Hash composition on the igniting element and the closed end of the shell, said shell being so constructed as to be burstable under the pressure generated by said deflagrating composition.

3. An electric squib comprising a closed shell with one or more weakening scores, furrows or scratches, an electric igniting element surrounded by a Hash composition and an auxiliary black powder charge in the portion of the closed shell between the Hash composition on the igniting element and the closed end of the shell, said shell being so constructed as to be burstable under the pressure generated by the black powder charge upon ignition.

4. An electric squib comprising a closed metal shell with one or more weakening 100 scores, furrows or scratches, an electric igniting element surrounded by a Hash composition and an auxiliary black powder charge in the portion of the closed shell between the Hash composition onthe igniting element and 105 the closed end of the shell, said shell being so constructed as to be burstable under the pressure generated by the black powder charge upon ignition.

5. .An electric squib comprising a closed 110 aluminum shell with one or more weakening scores, furrows or scratches, an electric igniting element surrounded by a Hash composition and an auxiliary black powder charge in the portion of the closed shell be- 115 tween the Hash composition on the igniting element and the closed'end of the shell.

In testimony whereof 'I aix my signature.

GUY F. ROLLAND.

described my invention, what I

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