US3677182A

US3677182A - Base ejecting projectile

Info

Publication number: US3677182A
Application number: US85071A
Authority: US
Inventors: Ralph Peterson
Original assignee: US Department of Army
Current assignee: US Department of Army
Priority date: 1970-10-29
Filing date: 1970-10-29
Publication date: 1972-07-18
Anticipated expiration: 1989-07-18

Abstract

A base ejecting projectile includes a casing defining a cavity, fuse means closing the cavity at one end and an end cap closing the cavity at the other end. Actuation of an ignition device and an expelling charge generates pressurized gas within the cavity, which pressurized gas causes a piston to slide within the cavity and expel a cargo therefrom. Escape of the pressurized gas from the cavity with an attendant signature noise is precluded by sealing means which prevent the rapid escape of pressurized gas from the cavity concurrently with or subsequent to cargo expulsion.

Description

United States Patent Peterson [451 July 18, 1972 541 BASE EJECTING PROJECTILE [21] Appl. No.: 85,071

[52] US. Cl. ..l02/66, 102/90 51 int. (I F42!) 13/46 [58] Held of Search ..l02/6, 39, 05, 66, 90

[56] References Cited UNITED STATES PATENTS 3,404,630 10/1968 Grandy ..l02/66 3,460,507 8/1969 Little et al.... ..102/65 x 3,437,245 4/1969 Hebert et al. ..102/65 X Primary Examiner-Verlin R. Pendegrass Attorney-Harry M. Saragovitz, Edward J. Kelly and Herbert Berl [ ABSTRACT A base ejecting projectile includes a casing defining a cavity, fuse means closing the cavity at one end and an end cap closing the cavity at the other end. Actuation of an ignition device and an expelling charge generates pressurized gas within the cavity, which pressurized gas causes a piston to slide within the cavity and expel a cargo therefrom. Escape of the pressurized gas from the cavity with an attendant signature noise is precluded by sealing means which prevent the rapid escape of pressurized gas from the cavity concurrently with or subsequent to cargo expulsion.

5 Claims, 6 Drawing Figures //V VE/V TOR, RAL PH PE TERSO/V M ATTORNEYS BASE EJECTING PROJECTILE The invention described herein may be manufactured, used and licensed by or for the Government for Governmental purposes without the payment to me of any royalties thereon.

BACKGROUND OF THE INVENTION This invention relates broadly to ordnance projectiles and in particular to base ejecting projectiles.

Base ejecting projectiles are cargo carrying projectiles which typically include a casing which defines a cargo cavity, the cavity being closed at the base of the projectile casing by a releasable end cap. The head end of the cargo cavity is closed by a slidable piston within the projectile casing, on the other side of which piston is positioned an expelling charge which may be of mortar propellant or the like. A fuse is ordinarily provided in the nose of the projectile casing. When such a base ejecting projectile is tired, the fusing mechanism will, at some selected point in the trajectory, initiate the expelling charge thereby generating gas under pressure. The expansion of the pressurized gas pushes the slidable piston against the cargo with a force sufficient to cause separation of the end cap from the projectile casing and ejection of both the cargo and the piston through the opening in the casing formed by the separation of the end cap.

The generation of pressurized gas within the projectile casing, in addition to expelling the cargo, often generates sufficient stress against the fusing mechanism to cause destruction of the fuse thereby permitting escape of the gases to the atmosphere. Thus, upon the occurrence of the actuation of the expelling charge in known base ejecting projectiles, the generated pressurized gas will escape from the projectile casing either as a result of the destruction of the fuse or as a result of the expulsion of the piston. Such escape of the pressurized gas to the atmosphere is undesirable because it generates a noise in the nature of a sharp report which is distinctly audible to target personnel. Thus, the sharp report caused by the rapid release of pressurized gas from within the projectile casing defines a signature characteristic which is readily ascertainable by target personnel thereby permitting them to take evasive action thereby reducing the effectiveness of the round.

Various approaches have been taken to minimize or eliminate the objectionable signature characteristic discussed above. For example, it has been proposed that the cargo be expelled by a spring-loaded device rather than by an explosive charge. This approach is unsatisfactory, however, because it increases the size of the projectile as well as increasing its cost. Another approach has been to retain the expelling charge within a flexible container which expands in response to the generation of pressurized gases. This approach has been found to be unsatisfactory, however, because the proposed flexible containers have been highly expensive and have required that the projectiles be greatly increased in length. Additionally, the use of such flexible containers has not avoided the problem of escape of pressurized gas as a result of destruction of the fusing mechanism. Still further, it has been proposed that the ef fect of the signature characteristic be minimized by increasing the altitude of ejection of the cargo. Although this has been acceptable for some cargos, it does nothing to avoid the problem. For other cargos, increased altitude of expulsion does not constitute an operationally satisfactory approach to the problem.

SUMMARY OF THE INVENTION In view of the foregoing background, the principal object of this invention is to provide a base ejecting projectile which reduces signature characteristics of the expulsion event to ambient noise levels.

A further object of the present invention is to provide a base ejecting projectile having a reduced signature characteristic which is low in cost and which is not larger in dimension than comparable known base ejecting projectiles.

A still further object of the present invention is to provide a base ejecting projectile wherein expulsion of the cargo occurs in response to the actuation of an expelling charge, and wherein the pressurized gas resulting from the actuation of the expelling charge is isolated from the projectile fuse and precluded from rapid escape from the projectile casing subsequent to expulsion of the cargo.

The foregoing objects and others not specifically enumerated are accomplished by a base ejecting projectile according to the present invention, one embodiment of which may include a casing defining a cavity therein, the casing having an opening at one end and an opening at the opposite end, a fuse including an ignition device mounted in and closing the opening at the one end of the casing, a releasable end cap mounted in and closing the opening at the other end of the body, a piston disposed within the cavity and slidable between a forward position and an aft position, the piston also dividing the cavity into an expelling charge chamber and a cargo chamber, an expelling charge disposed within the expelling charge chamber, which expelling charge is actuable in response to actuation of the ignition device of the fuse whereby to generate pressurized gas within the expelling charge chamber to displace the piston from the forward position to the aft position, and means for sealing the expelling charge chamber to preclude rapid escape of the pressurized gas therefrom concurrently with or subsequent to the actuation of the expelling charge.

BRIEF DESCRIPTION OF THE DRAWINGS A more complete understanding of the present invention may be had from the following detailed description, particularly when considered in the light of the attached drawings, wherein:

FIG. 1 is a cross-sectional view of a base ejecting projectile according to the invention with an empty cargo cavity and prior to actuation of the expelling charge;

FIG. 2 is a view similar to FIG. I but showing a base ejecting projectile according to the invention subsequent to actuation of the expelling charge and with the end cap separated from the projectile casing;

FIG. 3 is a partial view, partly in cross-section of the head end of the projectile of FIGS. I and 2;

FIG. 4 is a view similar to FIG. 3 showing the commence ment of the ignition of the expelling charge;

FIG. 5 is a view similar to FIGS. 3 and 4 showing a complete actuation of the expelling charge and the isolation of the fuse means from the generated pressurized gas; and

FIG. 6 is a view similar to FIGS. 3-5 showing the effect of further expansion of gas resulting from actuation of the expelling charge.

DETAILED DESCRIPTION Considering the present invention in more detail, and referring specifically to the drawings, a base ejecting projectile according to the invention is shown in FIGS. 1 and 2 and is designated generally by the reference numeral 10.

Projectile 10 comprises a casing 11 having a main body portion I2 and a head portion 14, the head portion 14 having a relieved annular channel 16 for receiving telescopically the head end of main body portion 12 thereover in rigidly secured relationship.

The main body portion 12 of casing 11 is provided with an opening 18 in which is releasably positioned an end cap 20. The head portion 14 of casing 11 is provided with an opening 22 in which is threadedly secured a fuse device 24 having an ignition means 23 (FIG. 3) associated therewith. Casing 11, end cap 20 and fuse device 24 cooperate to define a closed cavity within which is slidably mounted an expulsion piston 28. The outer peripheral surface of expulsion piston 28 is in sliding engagement with the inner surface of the main body portion 12 of casing II and the leakage of fluid between the peripheral surface of piston 28 and the inner surface of main body portion 12 is prevented by an O-ring seal 29 which is disposed in a suitable annular channel formed in the peripheral surface of expulsion piston 28.

Expulsion piston 28 cooperates with the interior of main body portion 12 and end cap 20 to define a cargo chamber 30 (FIG. 1) in which may be carried any of many types of ordnance cargos, e.g. an illumination charge or the like. Similarly, expulsion piston 28 cooperates with the inner surface of head portion 14 of casing 11 and fuse device 24 to define an expelling charge chamber 32 in which is rigidly received an expelling charge device designated generally by reference numeral 34.

As is evident from FIGS. 1 and 2, a plurality of stop pins 36 are disposed on the inner surface of main body portion 12 to extend radially inwardly of cargo chamber 30. Stop pins 36 are located adjacent the after end of cargo chamber 30 and cooperate to define a stop means for limiting the sliding movement of expulsion piston 28 from its forward position (FIG. 1) to its after position (FIG. 2).

Considering expelling charge device 34 in greater detail and with particular reference to FIGS. 3-6, it can be seen that the inner end of opening 22 in head portion 14 is provided with a radially inwardly extending annular shoulder 38 which cooperates with a complementary shoulder 40 on one end of an expelling charge cup 42 to axially position expelling charge device 34 within expelling charge chamber 32. The diameter of the outer surface of expelling charge cup 42 corresponds substantially to the diameter of annular shoulder 38 whereby to position and maintain expelling charge device 34 radially centrally of casing 11.

Annular shoulders

38 and 40 are retained in snug engagement by a spring ring 44 which is suitably received within an annular channel formed within the surface of opening 22.

Expelling charge device 34 includes expelling charge cup 42 in which is slidably positioned a plug 46 having a passage 47 extending longitudinally axially therethrough. Cup 42 and plug 46 cooperate to define a container in which is received a charge 49 of expelling material which may be any of many known materials such as mortar propellant. The inner surface of cup 42 adjacent shoulder 40 is relieved to define an annular channel 51 for slidably receiving plug 46 such that plug 46 is slidable between an after position (FIG. 3) and a forward position (FIG.

Disposed between plug 46 and the ignition means 23 of fuse device 24 is a deformable plate 54. Plate 54 includes a flat section having a centrally disposed opening 56 therethrough which is adapted for registry with passage 47, and a deformed section 58. Section 58 may be formed in the open V shape shown in FIG. 3 or it may be formed in any other suitable shape so long as it is capable of accomplishing the function of covering, selectively, opening 56 as is discussed below in detail. Additionally, plate 54 may be manufactured of any suitable deformable material such as sheet metal or the like.

The assembly of base ejecting projectile can be accomplished in a standard manner by anyone having ordinary skill in this art and briefly includes the positioning of a cargo within cargo chamber 30 and thereafter positioning and securing the component elements of the projectile in the known manner.

With projectile 10 assembled, it is then ready for being fired over a suitable target. After having been fired and upon the occurrence of a particular event as determined by the operation of fuse device 24, ignition device 23 is detonated to spit a flame through opening 56 in deformable plate 54 and passage 47 in plug 46 to ignite the material of expelling charge 49 as is best seen in FIG. 4. Ignition of the explosive of expelling charge 49 causes the generation of gas, the pressure of which rises very rapidly. The rapidly rising gas pressure within cup 42 generates a force against plug 46 which tends to displace plug 46 toward fuse device 24. The displacement of plug 46 from the position shown in FIG. 4 toward fuse device 24 and the position shown in FIG. 5 causes the deformation and flattening of the deformed section 58 of deformable plate 54 in such a manner as to cover opening 56 thereby precluding the escape of gas from within cup 42 to passage 47.

Continued increase in the pressure of the gas within cup 42 ultimately causes destruction of cup 42 (FIG. 6) thus releasing the pressurized gas into expelling charge chamber 32 thereby exerting gas pressure against the surface of expulsion piston 28. The pressure of the gas being exerted against the surface of expulsion piston is sufficient to generate a force thereagainst to displace piston 28 from the position shown in FIG. 1 toward the position shown in FIG. 2. The displacement of piston 28 in this manner causesthe exertion of a force against any cargo contained within cargo chamber 30 which force is transmitted by the cargo to bear against end cap 20. Because end cap 20 is releasably secured within opening 18 of main body portion 12, the exertion of force thereagainst by the cargo in response to the displacement of piston 28 causes end cap 20 to be displaced out of opening 18 thereby permitting the expulsion of cargo from chamber 30. Continued expansion of the pressurized gas resulting from the actuation of the expelling charge causes displacement of piston 28 within main body portion 12 until the piston engages stop pins 36. At this stage, the cargo should be completely expelle from the projectile.

Because of the sealing effect of piston 28 with the inner surface of main body portion 12, it can be seen that although the cargo is completely expelled from the projectile by the action of piston 28 bearing thereagainst, the gases generated by the actuation of expelling charge 49 are precluded from rapidly venting to the atmosphere through opening 18 by piston 28. Additionally, as noted above, the pressurized gases are isolated from fuse device 24 by the deformation of plate 54 and resulting closure of passage 47, thereby eliminating the possibility of fracture of the fuse structure and venting of the gases to the atmosphere. Thus, none of the pressurized gas is permitted to rapidly escape from within projectile 10, the signature characteristic heretofore experienced during the use of known base ejecting projectile structures is eliminated, and the effectiveness of the projectile is increased.

The various components of base ejecting projectile 10 can be manufactured from any of the many materials generally known by those skilled in the art. Similarly, as was noted above, the assembly of a base ejecting projectile 10 according to the invention can be accomplished by methods known to those having ordinary skill in the art. It is considered to be manifest, however, that the structure of base ejecting projectile as described above with respect to one embodiment defines an improved projectile to which many modifications and variations can be made without departing from the spirit and scope of this invention.

lclaim: l. A base ejecting projectile including: a casing defining a cavity therein, said casing having an opening at one end and an opening at the opposite end;

fuse means mounted in and closing said opening at said one end of said casing, said fuse means including an ignition device;

end cap means mounted in and closing said opening at said other end of said casing, said end cap means being ejectable from said opening in response to the exertion of force thereon from within said cavity;

piston means disposed within said cavity and slidable between a forward position and an after position therein, said piston means for dividing said cavity into an expelling charge chamber and a cargo chamber, said piston being slidable from said forward position to said after position in response to the generation of pressure within said expelling charge chamber;

expelling charge means disposed within said expelling charge chamber, said expelling charge means being actuable in response to actuation of said ignition device to generate pressurized gas within said expelling charge chamber;

means for sealing said expelling charge chamber to preclude rapid escape of said pressurized gas therefrom which includes;

means disposed in said cavity of said casing for defining a passage for communicating said ignition device and said expelling charge means which includes;

a plug having a longitudinally axial bore extending therethrough, said plug being slidable within said cavity from an after position to a forward position in response to the generation of said pressurized gas; and

means for covering said passage to preclude the escape of said pressurized gas therethrough.

2. A projectile according to claim 1 wherein said expelling charge means includes a cup rigidly mounted within said expelling charge chamber, said cup for containing a charge of expelling material, and further wherein said plug is slidably mounted within said cup.

3. A projectile according to claim 2 wherein said means for covering said passage comprises a plate disposed between said plug and said fuse means, said plate being deformable in response to displacement of said plug from said after position to said forward position, the deformation of said plate for effecting the covering of said passage.

4. A projectile according to claim 1 wherein said expelling charge means includes a cup rigidly mounted within said expelling charge chamber, said cup for containing a charge of expelling material and further wherein said plug is slidably mounted within said cup.

5. A projectile according to claim 4 wherein said means for covering said passage comprises a plate disposed between saidplug and said fuse means, said plate being deformable in response to displacement of said plug from said after position to said forward position, the deformation of said plate for effecting the covering of said passage.

Claims

1. A base ejecting projectile including: a casing defining a cavity therein, said casing having an opening at one end and an opening at the opposite end; fuse means mounted in and closing said opening at said one end of said casing, said fuse means including an ignition device; end cap means mounted in and closing said opening at said other end of said casing, said end cap means being ejectable from said opening in response to the exertion of force thereon from within said cavity; piston means disposed within said cavity and slidable between a forward position and an after position therein, said piston means for dividing said cavity into an expelling charge chamber and a cargo chamber, said piston being slidable from said forward position to said after position in response to the generation of pressure within said expelling charge chamber; expelling charge means disposed within said expelling charge chamber, said expelling charge means being actuable in response to actuation of said ignition device to generate pressurized gas within said expelling charge chamber; means for sealing said expelling charge chamber to preclude rapid escape of said pressurized gas therefrom which includes; means disposed in said cavity of said casing for defining a passage for communicating said ignition device and said expelling charge means which includes; a plug having a longitudinally axial bore extending therethrough, said plug being slidable within said cavity from an after position to a forward position in response to the generation of said pressurized gas; and means for covering said passage to preclude the escape of said pressurized gas therethrough.

5. A projectile according to claim 4 wherein said means for covering said passage comprises a plate disposed between said plug and said fuse means, said plate being deformable in response to displacement of said plug from said after position to said forward position, the deformation of said plate for effecting the covering of said passage.