US2615396A - Munition - Google Patents

Description

Oct. 28, 1952 F|E$ER r AL 2,615,396

' MUNITIQN Filed May 22, 1944 2 SHEETS-SHEET 1 Fig. 2'

Patented Oct. 28, 1952 MUNIT IQN.

Louis F. Fieser, Belmont, and Emanuel B. Hershberg, Stoughton, Mass., assignors to the United States of America as represented by the Secretary of the Army Application May 22, 1944, Serial No. 536,799

- 1 Claim.

The invention described herein maybe manufactured and used by or for the Government, for governmental purposes, without the payment to us of any royalty thereon.

This invention relates particularly to a small incendiary munition suited for concealment, safe carrying in a persons pocket, and efficient functioning as a fire starter.

A pocket-size fire starter is very useful in warfare for destroying material whichmi'ght be captured by the enemy'and other fire starting purposes.

In. the development of a pocket-size fire starter definitely effective for military use, a number of requirements were established. Fundamentally, the requirements are: (1) easy fabrication and filling; (2) high fuel content for a given Weight; (3) safety in carrying; (4) positive ignition under divers conditions, e. g., at low temperatures and after water immersion; and (5) adequate incendiary action with suitable time and temperature in burning.

A general object of the invention is to provide a pocket-size fire starter conforming to the'fundamental requirements in as nearly an ideal manner as possible. Further specific objects will becom apparent in the following-description. v

One significant feature of the invention isth utilization of a combustible plastic case which is easily manufactured, durable, resistant to an oilbasefuel filling, light in weight, and which has a distinctly favorable eifect on the burning of the fuel.

A case of exceptional effectiveness is constructed of cellulose nitrate plastic containing about 11% or more nitrogen-with about 25 to 30% camphor as a plasticizer and. with sufficient pigment or filler to give the compounded plastic a relatively high ash content. Preferably, the amount of fully calcined ash is about 1% or in the range of'about .5 to2 With respect to the functioning of the preferred type of plastic in the case, it is of interest to observe that upon ignition the case burns uniformly to form a porous shell of ash components and that the incandescent-shell has a wick-like and surface combustion action which results in a concentrated hum of prolonged high temperature.

The plastic case-may be made in various shapes and sizes and be providedwith igniters of various types and positions; but certain arrangements and treatments have been found to be important factors for increasing the efliciency of the munition, as will be further explained.

'For-a detailed explanatiomreference made to the drawing which illustrates two usual forms of the munition embodying principles and features of the invention.

In the drawing:

Figure 1 shows an enlarged longitudinal crosssection view of a fire starter having an extremely simple form;

Figure 2 shows an enlarged top plan view of the fire starter illustrated in Figure 1 for showing a detachable sealing means used thereon;

Figure 3 shows a partly sectioned plan View of a pocket incendiary having a fiat case form with an attached igniter;

Figure 4 shows an end elevation view of the flat form unit illustrated in Figure 3;

Figure 5 is an enlarged elevational view of the igniter shown in the assembly of Figures 3 and 4 detached from its casing;

Figure 6 is an enlarged longitudinal sectional view of the igniter.

In. the drawings similar parts bear the same numerals.

Referring to the drawings, particularly to Figures 1 and .2, I is a flammable plastic case molded to a cylindrical shape. Near one end, designated as the top for convenience, the case has a plastic partition 2 which acts as an end wall for the oil fuel chamber 3 and. as a seat'for the match-head or button 5, outside the chamber 3 and surround ed by the extended plastic side wall 4 of case I. At the otherend of case i, designated as the bottom, the chamber 3 has a plastic closure disc 6 which is securely cemented to the side walls of the caseby collodion (cellulose nitrate in acetone) after chamber 3 has been charged with the desired fuel. I

The match-head 5 is conveniently assembled to a kraft paper disc or washer 1 and adhesively bonded to the outer side of partition 2.

A suitable match-head composition is a uniform mixture of about 50 parts potassium chlorate (100% through No. -U. S. Standard sieve), about 30 parts antimony sulfide (100% through No. sieve), and about 20 parts dextrin through No. -80 sieve), the proportions being in parts by weight.

The match-head mixture described is made into'a plastic paste by adding water, formed into rolls which are cut .into discs ,1 inch long and inch in diameter. A disc still in plastic state is placed in the upper hollow portion of the case and the kraft paper disc 1 is pressed down-on top of the mix to form the button 5 with a thin layer of the mix below the disc adhering to the cellulose Percent Phosphorus Sand 30 Dextrin a 20 The scratcher block 8 is placed over the match- 4 low or depression 58 at the side is attached to case I3. The depression may also be at the top or bottom of the case.

The igniting capsule I! may have any suitable firing means associated with it, e. g., a pull-wire scratcher or, as illustrated in Figure 6, a timed firing mechanism. I

The ignition tube, in general, has the shape of a pencil or narrow tube and is attached to the case by cemented clip 59. At one end of the tube is the flammable plastic capsule l1 containing a friction or strike-anywhere match-head 45. A protective plastic-disc l9 closes one end of the capsule and aneedle-point firing pin 20 is in head compartment with the coated surface 9 away from the match-head 5. A plastic or thin metal cap 10, e. g. No. 30 standard gage steel with lacquer coating, is slipped over the scratcher block 8 onto the sides of the case and is sealed by the overlapping waterproof adhesive tape H. The adhesive tape ll encircles the cap l0 sealing its edge. At its outer end, ta-pe H is overlapped on itself to form a pull tab l2 for convenience of the user in removing the tape, cap and scratcher block in setting the fire starter in action.

Preferably, before putting the scratcher block 8 in place, the body of the fire starter is loaded with a fuel mixture through the opening at the bottom and the closing disc 6 is cemented to the body over this opening.

After the fire starter is fully assembled, the entire assembly may be dipped into a 5% solution of Vinylite (a copolymer of vinyl acetate and vinyl chloride) in acetone. The clip coating is intended to render the unit fire-resistant and more waterproof. Other types of non-inflammable coatings may be used, c. g., a solution of 16 parts Vinylite and 4 parts butylmethacrylate in 80 parts of ethyl acetate, or an acetone solution of polyvinylacetate.

To use the fire starter, match-head 5 is ignited by friction from the scratcher coating 9 on the scratcher block 8. The burning match-head initiates combustion of the case which becomes an incandescent mass of concentrated heat until the entire charge is consumed. Preferably, the case should burn without forming a large luminous flame.

The fuel charge 3 in the case may be a viscous liquid, a gel or solid.

A recommended filling is a 7-15% gel of a soap thickener in kerosene. The soap may be a 1 to 1 mixture of aluminum naphthenate and aluminum palmitate, a mixture comprising coprecipitated aluminum stearate and aluminum oleate, and various other soaps capable of gelling liquid hydrocarbon fuels. In general, the preferred soaps are normally solid mixtures of aluminum soaps in granular form.

The fuel may contain flammable resins, asphalt, dispersed finely-divided metal, such as powdered magnesium, or other thickening and heat-increasing additives.

The flat form of fire starter shown in Figures 3 and 4 comprises a case l3 having two parts I3a and i317 constructed of flammable plastic, preferably a cellulose nitrate plastic. The parts l3a and [3b are cemented together at flanges 14 by collodion (cellulose nitrate and acetone). One part of the case, 13a, has a filling hole l5 covered by a cellulose nitrate disc I6 cementedby collodion to seal the hole l5 after loading. An igniting agent a capsule or container placed in a holalignment with the match-head and in position to pierce the disc l9 and penetrate the matchhead 45 when released.

The' match-head 45 may be attached to the point of an ordinary office pin 2|, the head of the pin being cemented to a plastic disc 22 which forms the base of the igniter tube and closes the capsule l1. Satisfactory operation has been obtained in using a match-head from commercial strike-anywhere matches sold for household use. However, to insure more efiicient functioning, the match-head pellet 45 is embedded in Celluloid cement or in a cement of Glyptal resin and ethyl acetate with an added mixture of potassium chlorate and antimony sulfide, preferably about 12 parts of KClOz and 1 .part of SbSa. The match-head and ignitible cement filling I8 are thus fully protected from air and moisture in tubular capsule I 1. This short tubular compartment or capsule is fastened to a relatively longer brass tube I6b by extending telescopically therein with crimping'at 23 and application of collodion cement between the overlapping walls.

A readily available commercial phonograph needle serves as firing pin 20, which is set into a brass block 24 normally held against the pressure of a compressed sprin 25 by a looped wire 26 under tension to act as a restraining member. The wire 26 is looped through a small hole 21 in a projecting boss end of block 24. A brass washer 28 is disposed on the shoulder of the block 24 surrounding theboss to keep the block in a central position with relation to the spring 25 and the, sides of thetube 16b. The other end of the looped wire 26 under tension is wound around the stem of a brass screw 29 which is screwed tightly against a lead washer 30 and into a brass plug 3| at the end of the tube [6a opposite the capsule I'I.

A brass partitioning plug 32 is interposed between two sections I 6a and 16b of the igniter tube to act as a base for-one end of the spring 25 and to furnish a support for a glass ampoule 33 in the end section Mia. The partitioning plug 32 has a projection 34 and a groove 35 to serve as fastening to the brass tube [6b and copper tube 16a and for thus fixing the plug, in position. Modeling clay, such as Plasticine or equal, is placed in the groove 35 to serve as a plastic seal 36. The looped wire 26 is passed through a hole 31 bored through the partitioning plug 32 and penetrating through the clay seal 36. Tufts of absorbent cotton or similar material are placed at both ends of the glass ampoule compartment with copper tube "5a to serve as cushioning supports 38 and 39 for the glass ampoule 33 in order to prevent breakage of the ampoule by normal or accidental jarring.

The looped tension wire 26 which acts as a restraining member may be a tinned piano wire having a diameter of about 0.014 inch. This wire may be made of any suitablematerial and of tatuses proper size to withstand corrosive action-.;of.-:'-a

froinla-zgood 0.015 to 0.025 cm..and contains about /z cci of a corrosive liquid, such as a solution of CuGlhZHz-O,

distilled water and varied amounts ofglycerol,

depending .onthe rate of corrosion or: timing desired. For example, the solution may haveia composition of about .15 partsby weight of the cupric chloride dihydrate and'about 85 parts by weight of water containing up to about M parts by weight of glycerol with about parts by weight of cupric salt and about 1'6 parts-by weight of water.

A thin pliable strip of metal 40, e. g., brass, passed through a slot M located between the firing pin 28 in a restrained position and the match-head capsule ll, acts as an additional safety for preventing the firing pin from piercing the capsule, if by any possibility the firing pin is set in motion prematurely. This strip is removed in arming the fire starter.

The holes 42 and 43 located in the brass tube it?) serve as vent holes for gaseous products of combustion evolved from the ignited match-head. The vent holes may be left open or be sealed with waterproof tape to prevent access of water and dirt before the fire starter is being armed and made ready for use.

The brass tube section 161) extending from the partitioning plug 32 to the match-head capsule H and inclosing the firing mechanism preferably has thicker walls, about 0.03 inch, than the copper tube section lta which extends from the partitioning plug 32 to the screw head 29 and surrounds the glass ampoule 33. The copper tube section ltd may have a wall thickness of about 0.005 inch so that it yields to a sufficient pressure of about lbs, per square inch between a persons fingers with the result that the tube is bent and crushes the glass ampoule 33, thereby releasing the corrosive liquid contents for contacting and corroding the restraining wire 26 in a predetermined length of time.

For operating the fire starter with the igniter tube having a delayed action firing mechanism, tape is removed from vent holes 42 and 43, the bent safety strip 46 is straightened and removed from the slot 4|, the copper tube section lBa is pressed until the glass ampoule 33 is broken to release the corroding liquid into contact with the restraining wire 25, and the unit is planted or thrown to where it is intended to start incendiary action. After a period of about 15 minutes or as long as 25 hours, predetermined by the strength of the corroding liquid released from broken ampoule 33 and the corrosion-resistance of the restraining wire 26, this wire is ruptured by corrosion and releases the firing mechanism. The released firing pin in block 24 is forced by the compressed spring 25 to move abruptly toward the capsule H. The needle point of the firing pin in moving pierces the match-head capsule cover [9, then pierces the match-head 65, causing the match-head to ignite and start the burning of the flammable capsule H, which in turn starts the burning of the incendiary case and its fuel contents 53. Thus the ignition takes place noiselessly with very little friction by the sharp point of the needle puncturing the capsule and penetrating into the match-head.

By constructing the fuel case [3a and I3?) from a suitable cellulose nitrate plastic, the incendiary is made-to produce an intense heat. A black virgin stock cellulose nitrate with camphor plasticizer and sufficient pigment and/0r filler burns silently without making a bright flame.

While the different members of the igniter, such as the delayed timing means, the restraining means, the firing means, and the flammable capsule, have been described as functioning together in a unit, each of these, members maybe modified .or, in some instances be omitted without disturbing the functioning of the others. For example, the delayed timing may be omitted by removing screw 29 and straightening the end of the wire 26 so that the wire is free to move and directly release the'firing mechanism. -In-'p'lace of the mechanical firing means, a chemical may be used to initiate the burning of the material in the capsule, for example, after a reagent, such as dilute or concentrated sulfuric acid in glass ampoule 33 is released by fracturing the ampoule, this reagent may be made to flow directly into contact with another reactive chemical or to corrode through a partitioning member, such as a thin corrodible disc, to come into contact with another substance and thereupon produce an igniting flame.

A mixture consisting in one part hexamethylene tetramine with two parts of sodium peroxide forms a combustible known as Scheelite, which may be used as the chemical in the firing compartment of the igniter. This mixture is ignited when contacted by sulfuric acid.

In another adaptation, the glass ampoule similar to ampoule 33 may contain a substance which is spontaneously ignitible in air, as, for example, divinyl acetylene, diethyl zinc, triethyl boron or the like, without a mechanical firing mechanism but with provision for access of air and contact of the igniting fluid with a combustible plastic part of the igniter. On the other hand, such substances which are spontaneously ignitible in the air may be contained within an hermetically sealed bulb or capsule replacing the match-head capsule I! in alignment with the firing mechanism to obtain advantages of the delayed action mechanism and the safety means.

Although the described type of incendiary is particularly suitable as a pocket-size fire starter, it may be adapted for other uses, as, for example, as a unit in a scatter-type aerial bomb. In this adaptation, any number of units comprising hydrocarbon fuel-charged flammable plastic cases having individually attached igniters which inflame the cases upon rupturing may be scattered from a clustering body or a number of the cases may be expelled from an impacted tail-ejection bomb. The plastic cases may have an hexagonal or triangular shape for fitting into a bomb body of standardized shape.

It is to be understood that although the invention has been described with reference particularly to the illustrated fire starter units, other modifications come within the spirit andscope of the invention.

We claim:

An incendiary fire starter including a flammable nitrate cellulose case provided with a compartment, a charge of gelled hydrocarbon fuel in said compartment, and a matchhead composition, said compartment having a plurality of solid nitrate cellulose wall portions completely enclosing said charge in said compartment in a fluid tight manner, said matchhead composition being secured in direct contact with an outer surface of one of said wall portions and at a dis- 7 tance from the interior of said chamber de- Number termined by the thickness of the wall portion 1,327,899 to which said composition is attached. 1,329,503 LOUIS F. FIESER. 1,486,014 EMANUEL B. HERSHBERG. 5 1,484,190 1,539,609 REFERENCES CITED 2,034,020 The following references are of record in the 2,294,415 file of this patent: 2,328,277 UNITED STATES PATENTS 2383306 Number Name Date 506,548 Rockwell Oct. 10, 1893 u b r 795,632 Matthew July 25, 1905 152,972 960,094 Jackson May 31, 1910 u 5 8 Name Date Bemisderfer Jan. 13, 1920 Casey 1 Feb. 3, 1920 Dutcher Mar. 4, 1924 Ray Feb. 19, 1924 Taylor May 26, 192-5 Branchen Mar. 17, 1936 McBride Sept. 1, 1942 Hunt Aug. 31, 1943 Zimmer et a1. Aug. 28, 1945 FOREIGN PATENTS Country Date Great Britain 1920 France Sent. 11. 1939

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