US3888179A

US3888179A - Initiator for incendiary pellet

Info

Publication number: US3888179A
Application number: US334786A
Authority: US
Inventors: Kermit Nord; Francis C Wallenhorst
Original assignee: US Department of Army
Current assignee: US Department of Army
Priority date: 1973-02-23
Filing date: 1973-02-23
Publication date: 1975-06-10
Anticipated expiration: 1992-06-10

Abstract

This invention relates to an initiator for ignition and dispersal of a multiplicity of incendiary pellets from an impacting incendiary 40 mm cartridge. The initiator having a cylindrical combustible incendiary housing, an igniter housing charge operatively positioned in the cylindrical housing, a frangible wall means fixedly attached to the housing, a plurality of incendiary output pellets annularly positioned within the frangible means, means for trajectory improvement fixedly attached to the frangible wall means, and means for fuzing threadedly attached to the housing and intermediate to the trajectory improvement means and the plural incendiary output pellets. The initiator first ignites the igniter housing charge and the incendiary output pellets upon impact of the cartridge, and then secondly a short time thereafter disperses the ignited incendiary output pellets and distributes them for maximum effectiveness against a combustible target area.

Description

1 June 10, 1975 United States Patent 1191 Nord et al.

[ INITIATOR FOR INCENDIARY PELLET Primary Examiner-Verlin R. Pendegrass Inventors: Kermit Nord Harvest, Ala.; Francis C. wanenhorist, Coon Rapids Minn. Arromey, Agent, or Firm-Nathan Edelberg; Robert P.

Gibson; Max Yarmovsky The United States of America as [73] Assignee:

ABSTRACT represented by the Secretary of the Army, Washington, DC

This invention relates to an initiator for ignition and 74 00 %H6 mi 1 I. 6 m. mm M 0M1 1" 3 7 9 n" l "u 8 n" 2 Hm b 4 mm e 3 H m F 3 mm mun. 0 HS N M C a d m. M m P m F A UhF UH NUT 2 2 555 ll. ill

means, means for trajectory improvement fixedly at tached to the frangible wall means, and means for fuz [56] References Cited UNITED STATES PATENTS ing threadedly attached to the housing and intermediate to the trajectory improvement means and the plural incendiary output pellets. The initiator first ignites the igniter housing charge and the incendiary output pellets upon impact of the cartridge, and then secondly a short time thereafter disperses the ignited incendiary output pellets and distributes them for maximum effectiveness against a combustible target area.

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1,054,114 11/1951 102/68 5 Claims, 2 Drawing Figures PATENTEDJUH I 0 I915 CONFIDENTIAL INITIATOR FOR INCENDIARY PELLET GOVERNMENT INTEREST The invention described herein may be manufac tured, used and licensed by or for the Government for governmental purposes without the payment to us of any royalty thereon.

BACKGROUND OF THE INVENTION Various projectiles have been developed in the past to have incendiary capability against personnel and combustible materiel. The prior art incendiary device fired from artillery projectiles were not primarily concerned with maximum utilization of space within the projectile because of their relatively large volume. Prior art projectiles requiring more than one fuze to perform the dual function of ignition and dispersal of the incendiary could readily be accomplished within the given space limitations of these large shells. With the development of smaller, shoulder launched, 40 mm projectile, severe space limitations were imposed by the smaller volume. In order for the 40 mm incendiary projectile to maintain its maximum effective combustibility against an area, it is necessary to widely and uniformly disperse the incendiary material against the target area while the incendiary is still burning. Prior art devices having multiple distributable incendiary pellets have utilized a fuzing device for the ignition of the pellet and a separate fuze for rupturing of the projectile wall and dispersal of the pellet. This prior art dual fuzing means in the 40 mm projectile reduces the pellet payload capability, making it less effective against a target and more costly to manufacture because of the added mechanical and/or electrical actuating means necessary to accomplish the ignition and dispersal functions. The present invention overcomes the aforementioned deficiencies in the prior art devices by providing a satisfactory means for igniting and dispersing a multiplicity of incendiary pellets from a 40 mm projectile without the need for more than one fuzing means.

SUMMARY OF THE INVENTION The present invention relates to a projectile for incendiary pellets contained in small caliber cartridge e.g. a 40 mm cartridge, which has dual incendiary and screening capability and which is effective against personnel and combustible materiel. An impact fuze located in the ogive section of the cartridge activates an axially aligned burst charge which is held proximate thereto by a hollow cylindrical adapter assembly. The latter is operatively held intermediate to the fuze and a hollow cylindrical cup shaped projectile body which is incendiary and holds a main single igniter charge. The adapter assembly has a plurality of circumferentially located ports which provide communicating paths between the burster charge and the pellet igniters. A plurality of incendiary pellets are peripherally stacked in an annular space between the outer surface of the adapter assembly and the inner walls of a notched cylindrical skirt. The cylindrical shaped pellets have their open igniter ends positioned so that they face the circumferential adapter assembly igniter ports. The notched cylindrical skirt retains the pellets in their cylindrically stacked configuration during the launch. A central axial main charge bore is located proximate to the main charge and contains therein a pair of pellet igniters for the main charge incendiary. An ogive protects the fuze in the forward end and helps to give the projectile an improved ballistic trajectory. The ogive is crimped to the outer circumference of a cup shaped hollow collar open end. The notched skirt is crimped to the other end of the partially closed collar. A hollow cylindrical projectile body when ignited acts as a single incendiary. The projectile body is fixedly held within the other end of the notched skirt.

One of the objects of this invention is to provide an initiator for a plurality of incendiary pellets dispersed by a 40 mm projectile.

Another object of this invention is to provide a 40 mm projectile having incendiary pellets which can be initiated and dispersed after impact by a single fuzing means.

Another object of this invention is to provide a 40 mm incendiary projectile which is effective against both personnel and combustible materiel.

Another object of this invention is to provide an incendiary projectile which is effective against personnel and combustible materiel which can be launched from a held, shoulder fired weapon.

Another object of this invention is to provide a 40 mm incendiary projectile which is safe for storage, handling, transporting and firing.

Another object of this invention is to provide a 40 mm incendiary projectile which is compatible in size, weight and ballistic trajectory of existing 40 mm ammunition.

Another object of this invention is that it should provide a 40 mm incendiary dual purpose projectile which is suitable for low cost mass production.

Another object of this invention is that all the materials, of the loaded 40 mm incendiary projectile, in contact with each other should be mutually compatible.

While certain objects, features and advantages of the present invention have been specifically pointed out, others will become apparent from the following description taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view and partial cross-sectional view taken along a plane through the longitudinal axis of the preferred embodiment of the initiator for the incendiary pellets and main charge of a 40 mm projectile.

FIG. 2 is a cross-sectional view of the projectile illustrated in FIG. 1 taken about line 22 showing the adapter assembly parts in relation to the incendiary pellets.

Throughout the following description like reference numerals are used to denote like parts in the drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1 a hollow magnesium projectile housing 10 has a cup shape side wall 12, a closed end 13 and a partially open top wall 16. The housing contains therein a single main igniter charge 14. The top wall 16 of the projectile body 10 has an axial threaded bore 18 therein. A hollow-cylindrical aluminum pellet skirt 20 has a plurality of circumferential notches 22 located in the outer peripheral surface of the skirt wall 24. One open end of the pellet skirt 20 is fixedly attached to the projectile body side wall 12, the other open end is peripherally attached to one end of a cylindrically flanged collar 26. The collar flange wall 28 supports an impact activated fuze 30 which is crimped to an adapted flange 32 of a cylindrical adapter assembly 31. The adapter assembly tubular member 34 has a burster charge central cylindrical bore 36 which communicates on one end with an impact fuze lead train detonator 38. The other end of the central bore 36 communicates with a smaller axial main charge igniter bore 40 which retains therein two main charge igniter pellets 42 and 42'. The other end of the adapter assembly 34 has a cylindrical externally threaded extension 44 which operatively engages the projectile body threaded bore 18. The main charge igniter pellets 42 and 42' are held within the main charge igniter bore 40 by pressure sensitive tape 46. Intermediate to the igniter pellet 42 and the lead train 38 is the burster charge 48. A pair of burster pellets 49, 49' are operatively positioned in the upper and lower halves of the burster charge 48. A plurality of incendiary pellet ports 50 are radially positioned circumferentially around the adapter assembly central bore 36 and communicates therewith. Intermediate a smooth inner skirt wall 25 and the outer wall surface of the adapter assembly 34 are a plurality of annularly stacked incendiary pellets S2, 52' and 52". An annular incendiary pellet channel 54 is intermediate to the adapter assembly outer wall 35 and the open end of the cup shaped incendiary pellet sleeve 56 and communicates with the adapter assembly incendiary pellet ports 50. An igniter pellet 58 partially fills the incendiary pellet sleeve 56 and has one face adjacent to the open end of the pellet sleeve. Intermediate to the igniter pellet mix 58 and the closed end ofthe pellet sleeve 56 is igniter sleeve pellet 60. An ogive 62 has a blunt closed end 64 and an open end 66 which is crimped to the flanged collar 26 at the collar open crimping end 27 forming a protective shield for the impact fuze 30 and giving the projectile the necessary streamline contour for a good ballistic trajectory. The flanged end collar end 28 is fixedly attached to the other open end of the notched skirt 22.

In operation the aforedescribed device uses the same energy source to first cause ignition of the multiple

incendiary output pellets

52, 52' and 52" and ignition of the single incendiary material 12 source main charge igniter pellets 42, 42', and then to develop pressure for skirt wall 24 rupture so that the

output pellets

52, 52' and 52" will be properly distributed for maximum incendiary effect to an area target.

A suitable mixture for the igniter pellets 58, for the

output pellets

52, 52 and 52" and for the main charge igniter pellets 42, 42' and for the burster pellets 49, 49' would consist of a mixture of barium chromate 75 percent by weight having a particle size of 1.4 as determined by a Fisher Sub Sieve Sizer, boron 19 percent by weight having a particle size of 0.86, potassium perchlorate percent by weight having an 11.0 particle size, and a VAAR Binder manufactured by Union Carbide having l percent by weight solid material residual after evaporation A suitable mixture for the sleeve igniter pellets 60 would consist of zirconium powder 65 percent by weight having a particle size of 2.5 t 1.0 micron, ferric oxide 25 percent by weight having a particle size which will pass through a No. 325 sieve, and SUPERFLOSS as manufactured by Johns Manville percent by weight having a specific gravity of 2.30, pH 9.0 passing through No. 325 sieve. A suitable mixture for the burster charge 48 to surround the

burster pellets

49 and 49 would be boron potassium nitrate. A suitable mixture for the single main igniter charge would consist of atomized aluminum 23 percent by weight.

5 iron oxide 75 percent by weight having a particle size which will pass through a No. 325 sieve and a VAAR binder 2.0 percent solid residual after evaporation as manufactured by Union Carbide.

Referring now to FIG. 2 the radially positioned incendiary pellets 52 are shown intermediate the notched outer skirt wall 24 and the adapter assembly 34 having radially positioned incendiary pellet ports 50 which lead into and communicate with the annular pellet channel 54.

From the above description it will be evident that the invention provides in the preferred embodiment an initiator for incendiary pellets which does not require separate fuzing means for ignition of the incendiary pellets and single charge impact incendiary and a fuzing means for the dispersion of the pellets thereby allowing the present invention to be incorporated with improved incendiary effectiveness into the small hand held shoulder fired 40 mm cartridge.

We wish it to be understood that we do not desire to be limited to the exact detail of construction shown and described for obvious modifications will occur to a person skilled in the art.

What is claimed is:

I. A multiple pellet dispensing incendiary cartridge which comprises:

a cylindrical housing incendiary material having a partially open end and a closed end; an igniter charge in said housing;

a hollow frangible wall means having open ends, wherein one of said ends is fixedly attached to said partially open housing end;

a plurality of incendiary means annularly positioned within said frangible means;

means for trajectory improvement fixedly attached to said other frangible wall means end; and

means for fuzing, threadedly attached to said housing partially open end and intermediate to said trajectory improvement means and said plural incendiary means, for first igniting said igniter charge and said incendiary means upon impact of said cartridge, and then secondly for dispersing said ignited incendiary means in a combustible target area.

2. An incendiary cartridge as recited in claim 1 wherein said frangible wall means comprises:

a cylindrical aluminum tubing having an inner smooth wall and an outer notched wall.

3. An initiator for an incendiary cartridge as recited in claim 2 wherein said incendiary means comprises;

a hollow cylindrical magnesium cup shaped sleeve having a closed end and a open end;

an igniter sleeve pellet operatively positioned within said sleeve adjacent to said closed end;

an igniter pellet operatively positioned within said sleeve intermediate to said sleeve pellet and said sleeve open end.

4. An incendiary cartridge as recited in claim 3 wherein said means for trajectory improvement com- 5 prises:

a hollow ogival member having a blunt closed end and an open end of larger diameter than said blunt end;

a hollow cylindrical cup shaped collar having an open end crimpedly affixed to said open ogival member end. and a flanged end fittahly attached to said other frangible wall means end. S. An incendiary cartridge as recited in claim 4 wherein said means for fuzing comprises:

an impact fuze;

a lead train detonator operatively positioned within said impact fuze and responsive to said impact fuze;

an adapter assembly, having an adapter flange fixedly held intermediate said impact fuze and said collar

Claims

1. A multiple pellet dispensing incendiary cartridge which comprises: a cylindrical housing incendiary material having a partially open end and a closed end; an igniter charge in said housing; a hollow frangible wall means having open ends, wherein one of said ends is fixedly attached to said partially open housing end; a plurality of incendiary means annularly positioned within said frangible means; means for trajectory improvement fixedly attached to said other frangible wall means end; and means for fuzing, threadedly attached to said housing partially open end and intermediate to said trajectory improvement means and said plural incendiary means, for first igniting said igniter charge and said incendiary means upon impact of said cartridge, and then secondly for dispersing said ignited incendiary means in a combustible target area.

2. An incendiary cartridge as recited in claim 1 wherein said frangible wall means comprises: a cylindrical aluminum tubing having an inner smooth wall and an outer notched wall.

3. An initiator for an incendiary cartridge as recited in claim 2 wherein said incendiary means comprises: a hollow cylindrical magnesium cup shaped sleeve having a closed end and a open end; an igniter sleeve pellet operatively positioned within said sleeve adjacent to said closed end; an igniter pellet operatively positioned within said sleeve intermediate to said sleeve pellet and said sleeve open end.

4. An incendiary cartridge as recited in claim 3 wherein said means for trajectory improvement comprises: a hollow ogival member having a blunt closed end and an open end of larger diameter than said blunt end; a hollow cylindrical cup shaped collar having an open end crimpedly affixed to said open ogival member end, and a flanged end fittably attached to said other frangible wall means end.

5. An incendiary cartridge as recited in claim 4 wherein said means for fuzing comprises: an impact fuze; a lead train detonator operatively positioned within said impact fuze and responsive to said impact fuze; an adapter assembly, having an adapter flange fixedly held intermediate said impact fuze and said collar flange and an integral tubular member axially aligned with said adapter flange, said tubular member having a main charge axial igniter bore, a burster charge located in a burster charge axial central bore larger in diameter than said igniter bore, and a plurality of radially positioned incendiary pellet ports whose longitudinal axis lie in a plane perpendicular to the longitudinal axis of said cartridge, for first igniting respectively said igniter housing charge and said incendiary peLlets and secondly subsequently dispersing said pellets.