Title:
TEAR GAS GRENADE
United States Patent 3795197
Abstract:
A tear gas grenade including a canister and a top crimped to the canister so as to leave a marginal safety pressure relief opening. Emission holes are provided in the canister adjacent opposite ends thereof. A tubular charge pellet is supported in the canister spaced from opposite ends thereof. Igniter tubes are provided adjacent inner and outer combustion surfaces of the pellet. Igniter washers are provided on end combustion surfaces of the pellet. The grenade elements are arranged to provide maximum dissemination of the gas with safety and such that the gas has a minimal tendency to diffuse after emission.
US Patent References:
Fast burning type candle
Conkling - January 1933 - 1895149
Hand grenade or aerial bomb
Young - February 1933 - 1897948
Gas grenade
Weinert - November 1960 - 2959127
GRENADE FLOATATION SHROUD HOLDING AND RELEASING ARRANGEMENT EMPLOYING PLASTIC CONNECTOR
Beers - February 1969 - 3427973
GRENADE FLOTATION ATTACHMENT
Angelos et al. - December 1969 - 3482517
Fast burning type candle
Conkling - January 1933 - 1895149
Hand grenade or aerial bomb
Young - February 1933 - 1897948
Gas grenade
Weinert - November 1960 - 2959127
GRENADE FLOATATION SHROUD HOLDING AND RELEASING ARRANGEMENT EMPLOYING PLASTIC CONNECTOR
Beers - February 1969 - 3427973
GRENADE FLOTATION ATTACHMENT
Angelos et al. - December 1969 - 3482517
Application Number:
05/275509
Publication Date:
03/05/1974
Filing Date:
07/27/1972
View Patent Images:
Export Citation:
Primary Class:
International Classes:
F42B12/50; F42B12/02; F42B27/06
Field of Search:
102/64-66
Primary Examiner:
Pendegrass, Verlin R.
Attorney, Agent or Firm:
Bosworth, Sessions & McCoy
Claims:
What is claimed is
1. A gas grenade comprising a canister, gas emission holes in said canister adjacent opposite ends thereof, a tubular charge in said canister comprising a mixture of vaporizable chemical agent and a combustible material, said charge having radially spaced inner and outer combustion surfaces and end combustion surfaces, a rib on the inner wall of said canister, said rib spacing said outer combustion surface away from a wall of said canister to enhance combustion thereof and to provide a free space for passage of evolved gas, a crack in said charge tube extending radially from said inner combustion surface to said outer combustion surface and providing exposed radially extending surface area for combustion, said charge being oriented in said canister so that said crack is diametrically opposite said rib, means supporting and spacing said charge from opposite ends of said canister, an inner charge igniter tube extending through said tubular charge in close contact with said inner combustion surface, an outer charge igniter tube disposed about the outer periphery of said charge in close contact with said outer combustion surface, an igniter washer on each end surface of said tubular charge contacting said inner and outer igniter tubes, and fuze means in said canister adjacent said inner charge igniter tube for igniting said inner tube, ignition of said inner tube resulting in ignition of said igniter washers and outer igniter tube, whereby combustion of said igniter tubes and washers effects evolution of gas from said inner and outer and end combustion surfaces.
2. A gas grenade comprising a canister, gas emission holes in said canister adjacent opposite ends thereof, a separate top on said canister, said top having a marginal portion spaced slightly from a corresponding portion of said canister to define therewith a narrow circumferentially extending safety pressure relief opening, a tubular charge in said canister comprising a mixture of vaporizable chemical agent and a combustible material, said charge having radially spaced inner and outer combustion surfaces and end combustion surfaces, means supporting and spacing said charge from opposite ends of said canister, an inner charge igniter tube extending through said tubular charge in close contact with said inner combustion surface, an outer charge igniter tube disposed about the outer periphery of said charge in close contact with said outer combustion surface, an igniter washer on each end surface of said tubular charge contacting said inner and outer igniter tubes, and fuze means in said canister adjacent said inner charge igniter tube for igniting said inner tube, ignition of said inner tube resulting in ignition of said igniter washers and outer igniter tube, whereby combustion of said igniter tubes and washers effects evolution of gas from said inner and outer and end combustion surfaces.
3. A gas grenade as claimed in claim 2 wherein said spacing and support means includes cylindrical screens at opposite ends of said canister serving as filter and cooling means for gas evolved from portions of said combustion surfaces.
4. A gas grenade as claimed in claim 3 wherein said spacing and support means includes a screen washer between each of said screen cylinders and said igniter washers, said washers filtering and cooling a portion of said gas evolved from said combustion surfaces.
5. A gas grenade comprising a canister, gas emission holes in said canister adjacent opposite ends thereof, a tubular charge in said canister comprising a mixture of vaporizable chemical agent and a combustible material, said charge having radially spaced inner and outer combustion surfaces and end combustion surfaces, means supporting and spacing said charge from opposite ends of said canister, an inner charge igniter tube extending through said tubular charge in close contact with said inner combustion surface, an outer charge igniter tube disposed about the outer periphery of said charge in close contact with said outer combustion surface, an igniter washer on each end surface of said tubular charge contacting said inner and outer igniter tubes, and fuze means in said canister adjacent said inner charge igniter tubes for igniting said inner tube, said fuze means including a pyrotechnic train having a terminal composition comprising a stoichiometric mixture of fine aluminum powder and cupric oxide in a nitro-cellulose matrix, ignition of said inner tube resulting in ignition of said igniter washers and outer igniter tube, whereby combustion of said igniter tubes and washers effects evolution of gas from said inner and outer and end combustion surfaces.
6. A gas grenade comprising a canister, gas emission holes in said canister adjacent opposite ends thereof, a separate top on said canister, said top having a marginal portion spaced slightly from a corresponding portion of said canister to define therewith a narrow circumferentially extending safety pressure relief opening, a tubular charge in said canister comprising a mixture of vaporizable chemical agent and a combustible material, said charge having radially spaced inner and outer combustion surfaces, means supporting and spacing said charge from opposite ends of said canister, means contacting at least one of said combustion surfaces for igniting said charge, and fuze means in said canister for igniting said charge igniting means.
7. A gas grenade as claimed in claim 6 including a crack in said charge tube extending radially from said outer combustion surface to said inner combustion surface and providing radially extending surface area for combustion.
1. A gas grenade comprising a canister, gas emission holes in said canister adjacent opposite ends thereof, a tubular charge in said canister comprising a mixture of vaporizable chemical agent and a combustible material, said charge having radially spaced inner and outer combustion surfaces and end combustion surfaces, a rib on the inner wall of said canister, said rib spacing said outer combustion surface away from a wall of said canister to enhance combustion thereof and to provide a free space for passage of evolved gas, a crack in said charge tube extending radially from said inner combustion surface to said outer combustion surface and providing exposed radially extending surface area for combustion, said charge being oriented in said canister so that said crack is diametrically opposite said rib, means supporting and spacing said charge from opposite ends of said canister, an inner charge igniter tube extending through said tubular charge in close contact with said inner combustion surface, an outer charge igniter tube disposed about the outer periphery of said charge in close contact with said outer combustion surface, an igniter washer on each end surface of said tubular charge contacting said inner and outer igniter tubes, and fuze means in said canister adjacent said inner charge igniter tube for igniting said inner tube, ignition of said inner tube resulting in ignition of said igniter washers and outer igniter tube, whereby combustion of said igniter tubes and washers effects evolution of gas from said inner and outer and end combustion surfaces.
2. A gas grenade comprising a canister, gas emission holes in said canister adjacent opposite ends thereof, a separate top on said canister, said top having a marginal portion spaced slightly from a corresponding portion of said canister to define therewith a narrow circumferentially extending safety pressure relief opening, a tubular charge in said canister comprising a mixture of vaporizable chemical agent and a combustible material, said charge having radially spaced inner and outer combustion surfaces and end combustion surfaces, means supporting and spacing said charge from opposite ends of said canister, an inner charge igniter tube extending through said tubular charge in close contact with said inner combustion surface, an outer charge igniter tube disposed about the outer periphery of said charge in close contact with said outer combustion surface, an igniter washer on each end surface of said tubular charge contacting said inner and outer igniter tubes, and fuze means in said canister adjacent said inner charge igniter tube for igniting said inner tube, ignition of said inner tube resulting in ignition of said igniter washers and outer igniter tube, whereby combustion of said igniter tubes and washers effects evolution of gas from said inner and outer and end combustion surfaces.
3. A gas grenade as claimed in claim 2 wherein said spacing and support means includes cylindrical screens at opposite ends of said canister serving as filter and cooling means for gas evolved from portions of said combustion surfaces.
4. A gas grenade as claimed in claim 3 wherein said spacing and support means includes a screen washer between each of said screen cylinders and said igniter washers, said washers filtering and cooling a portion of said gas evolved from said combustion surfaces.
5. A gas grenade comprising a canister, gas emission holes in said canister adjacent opposite ends thereof, a tubular charge in said canister comprising a mixture of vaporizable chemical agent and a combustible material, said charge having radially spaced inner and outer combustion surfaces and end combustion surfaces, means supporting and spacing said charge from opposite ends of said canister, an inner charge igniter tube extending through said tubular charge in close contact with said inner combustion surface, an outer charge igniter tube disposed about the outer periphery of said charge in close contact with said outer combustion surface, an igniter washer on each end surface of said tubular charge contacting said inner and outer igniter tubes, and fuze means in said canister adjacent said inner charge igniter tubes for igniting said inner tube, said fuze means including a pyrotechnic train having a terminal composition comprising a stoichiometric mixture of fine aluminum powder and cupric oxide in a nitro-cellulose matrix, ignition of said inner tube resulting in ignition of said igniter washers and outer igniter tube, whereby combustion of said igniter tubes and washers effects evolution of gas from said inner and outer and end combustion surfaces.
6. A gas grenade comprising a canister, gas emission holes in said canister adjacent opposite ends thereof, a separate top on said canister, said top having a marginal portion spaced slightly from a corresponding portion of said canister to define therewith a narrow circumferentially extending safety pressure relief opening, a tubular charge in said canister comprising a mixture of vaporizable chemical agent and a combustible material, said charge having radially spaced inner and outer combustion surfaces, means supporting and spacing said charge from opposite ends of said canister, means contacting at least one of said combustion surfaces for igniting said charge, and fuze means in said canister for igniting said charge igniting means.
7. A gas grenade as claimed in claim 6 including a crack in said charge tube extending radially from said outer combustion surface to said inner combustion surface and providing radially extending surface area for combustion.
Description:
BACKGROUND OF THE INVENTION
This invention relates to grenades for the dispensing of riot control agents, particularly tear-producing gases, and to improvements in such grenades.
Chemical agents employed for riot control and similar purposes are usually the so-called tear gases, particular examples being those commonly known as CN and CS. The effectiveness of such agents for these purposes is determined not only by the characteristics of the agents themselves but also by the means by which they are disseminated which is, typically, a grenade. For effective use of the tear gas grenade as a riot control means it is desirable that there be rapid dissemination of the tear-producing agent both to obtain a rapid riot control result and also to prevent "throwback" of the grenade. Throwback occurs when the grenade can be picked up and hurled back before sufficient tear-producing agent has been emitted in a proper pattern to nullify such a reaction.
Another desirable characteristic is that the tear-producing agent itself, once disseminated, have a minimum tendency to diffuse. The agent should tend to hover close to the ground for a substantial time. Along with rapid dissemination and minimum tendency to diffuse of the tear-producing agent it is desirable for humanitarian reasons to avoid injury or mutilation such as by flying fragments or burning particles emitted from the grenade. These characteristics are determined in substantial part by the manner and rate at which the tear-producing gas is generated which, in turn, are determined by the characteristics of the grenade elements and their arrangement to form the grenade.
In a typical tear gas grenade presently in use the chemical or tear-producing agent is mixed with a heat generating material such as smokeless powder and the mixture is pressed into a can. The top surface of the mixture is covered with a slurry of priming material and a fuze is provided in the top of the canister. In operation, the fuze ignites the priming materials which in turn ignite the heat-generating material. Heat from the heat-generating material volitalizes the chemical agent. The surface area provided for ignition of the priming materials and volitalization of the chemical agent is rather limited so that the dissemination of tear-producing agent is not as rapid as desired while the tear-producing agent that is produced is disseminated at such a high temperature that it is very light and tends to diffuse.
SUMMARY OF THE INVENTION
It is a general object of this invention to provide a grenade adapted for the dissemination of tear gas or similar non-lethal riot control agent that is improved over grenades of the same type presently in use. A particular object is the provision of such a grenade that provides more rapid dissemination of tear-producing agent while substantially eliminating the emission of flying fragments and burning particles.
Another object is the provision of such a grenade in which the emitted tear-producing gas has minimum tendency to diffuse and tends to hover close to the ground for substantial periods of time.
Still another object of this invention is the provision of an improved fuze for such a grenade which provides greater ignition reliability.
A preferred embodiment of the present invention includes a canister having gas emission holes adjacent opposite ends thereof. A tubular charge having radially spaced inner and outer combustion surfaces is supported in the canister spaced from opposite ends thereof. An inner charge igniter tube extends through the tubular charge in close contact with the inner combustion surface and an outer charge igniter tube is disposed about the outer periphery of the charge in close contact with the outer combustion surface. An igniter washer is positioned on each end surface of the tubular charge and provides an ignition path between inner and outer igniter tubes. Fuze means is provided in the canister adjacent the inner charge igniter tube for igniting it. The igniter washers are ignited from the inner tube and ignite the outer igniter tube. Combustion of the igniter washers and tubes effects evolution of gas from both the inner and outer combustion surfaces and the end surfaces of the charge.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a vertical sectional view of a tear gas grenade embodying the present invention.
FIG. 2 is a sectional view of the grenade of FIG. 1 along the line 2--2 thereof.
FIG. 3 is a perspective view of the tubular charge pellet of the grenade.
FIG. 4 is a perspective view of one of the screen cylinders of the grenade.
FIG. 5 is a perspective view of one of the screen washers of the grenade.
FIG. 6 is a perspective view of the outer igniter tube of the grenade.
FIG. 7 is a perspective view of the inner igniter tube of the grenade.
FIG. 8 is a perspective view of an igniter washer.
FIG. 9 is a diagrammatic view of the grenade top illustrating the extent of the marginal safety release opening in the grenade.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A grenade according to the present invention includes a canister 10, preferably formed of metal such as tinned steel, and having a flange 11 extending around its open top. A rib 12 extends inwardly from the inner surface of the canister through its full length. A top 14 has a peripheral lip 15 which is crimped to the canister so as to form a marginal pressure relief opening 15a between the top and the flange 11. A number of emission holes 16 are provided in the canister adjacent its top and bottom which permit the escape of tear-producing gas.
The grenade elements are arranged in canister 10 as shown in FIG. 1. Positioned in the bottom of the canister is a spacing and support means in the form of a screen cylinder 17. Screen cylinder 17 is preferably about 1/2 to 3/4 of the diameter of canister 10 and formed of steel wire mesh. The screen cylinder serves as a supporting and spacing element and as a filter and cooling element as will be described below. Supported by and above screen cylinder 17 is a tubular charge pellet 20. Pellet 20 may be a mixture of one of the usual tear-producing agents such as that commonly known as CS or that known as CN, with a heat generating material such as smokeless powder. The mixture is molded into a tubular pellet as shown in FIG. 3 having an inner combustion surface 21 and an outer combustion surface 22. The pellet is released from the mole in such a manner as to produce a radial crack 23 which runs the length of the pellet between the outer and inner combustion surfaces. Crack 23 is preferably only a "hair-line" crack but assists greatly in promoting combustion of pellet 20.
Positioned about the outer combustion surface of pellet 20 in close contact therewith is an outer igniter tube 24 which may be made of fabric such as muslin which has been soaked in a solution to impart the proper pyrotechnic characteristics thereto. Igniter washers 25, 25a are positioned on opposite end surfaces of pellet 20 and overlap the outer igniter tube 24. The igniter washers are also preferably made of muslin and treated in the same manner as the outer igniter tube.
Screen washers 26 and 27 are positioned over the igniter washers on the upper and lower end surfaces of pellet 20. The screen washers distribute the weight of pellet 20 over the end surfaces thereof and act as supporting elements for the pellet, igniter washers and outer igniter tube. The screen washers 26 and 27 also serve as filters in a manner to be described below. Seated on the upper screen washer 26 is a second screen cylinder 30 which is identical to screen cylinder 17 and performs an identical function. An inner igniter tube 32 extends the length of the can, passing through the central opening in pellet 20 in close contact with igniter washers 25 and 25a and with inner combustion surfaces 21 and through screen washers 26 and 27 and screen cylinders 17 and 30. Inner igniter tube 32 is identical in material and treatment to outer igniter tube 24 and the igniter washers and has substantially the same purpose as to inner combustion surface 21 that the outer igniter tube and igniter washers have as to outer combustion surface 22 and the end surfaces of pellet 20.
In the top 14 of the grenade is a brass ferrule 34 having inner threads to receive a fuze 37. Fuze 37 may be a standard military M201A1 fuze but preferably is a fuze of that type modified according to the present invention to improve its ignition characteristics for cooperation with the igniter tubes and igniter washers. Fuze 37 includes a body 39 having an opening 40 therein to receive a series of chemical compositions indicated at 42a, 42b, and 42c forming a pyrotechnic train 42. The pyrotechnic train 42 determines the characteristics of the fuze such as delay time and the combustion intensity of the flash imparted to the inner igniter tube 32. As modified according to the present invention the pyrotechnic train is terminated with a composition 44 which has a booster effect along with the terminating composition employed in the unmodified M201A1 fuze. The characteristics of terminating composition 44 make it particularly suitable for use in igniting materials of the comppsition of igniter tubes 32 and 24 and igniter washers 25, 25a. Terminating Composition 44 consists of a stoichiometric mixture of fine aluminum powder and cupric oxide in a nitrocellulose matrix.
At the top of the pyrotechnic train 42 is a conventional percussion cap 46 which is adapted to be struck by a conventional firing pin 47 and provides a spark to initiate combustion in the pyrotechnic train 42. The firing pin 47 is normally retained in the cocked position by a lever 49 and a safety pin 50 which holds both the firing pin 47 and lever 49 in their normal positions.
The grenade is assembled by first inserting screen cylinder 17 into the bottom of canister 10. Screen washer 27 is then placed over the screen cylinder. Pellet 20 and the igniter tubes and washers will have been formed previously. The outer igniter tube 24 is preferably positioned about the exterior of the pellet in close contact with the outer combustion surface. Lower igniter washer 25a is placed on lower screen washer 27. The combination of pellet and outer igniter tube is then placed on the lower igniter washer. Preferably, the pellet is oriented so that crack 23 is diametrically opposite rib 12 for reasons described below. Upper igniter washer 25 is then placed over the upper end surface of pellet 20 and overlaps outer igniter tube 24. Upper screen washer 26 is next positioned over igniter washer 25. Upper screen cylinder 30 is then seated on upper screen washer 26 and inner igniter tube 32 is passed through the central openings in pellet 20, igniter washers 25 and 25a and screen washers 26 and 27 to the bottom of canister 10.
Top 14 including ferrule 34 is then sealed onto canister 10. The top is positioned so that the lip 15 engages the flange 11 on the canister. The canister is then placed in conventional can sealing apparatus to crimp the lip 15 over the flange and bend flange and lip downwardly. The slight pressure relief opening 15a can be formed during sealing by arranging the canister in the sealing apparatus "off center" so that unequal crimping and bending pressure is applied around the periphery of the canister and top. The result is the area 15a of less effective sealing which serves as a pressure relief opening should the emission holes 16 become too constricted. Area 15a extends through about 1/3 of the circumference of top 14 as shown at A in FIG. 8. The portion of the circumference indicated as B is that having the conventional tight sealing crimp.
Arrangement of the elements of the grenade as illustrated in the drawing provides distinct advantages compared to existing tear gas grenades in the rapid dissemination of gas and in the partial cooling thereof to prevent its rapid diffusion. In the operation of the tear gas grenade, the fuze is ignited in the conventional manner and the pyrotechnic train 42 produces the proper series of combustion steps to the terminating composition 44. The terminating composition ignites the inner igniter tube 32 which in turn ignites the upper and lower igniter washers 25, 25a. The igniter washers ignite the outer igniter tube 24 at both ends. Burning of the inner and outer igniter tubes along the inner and outer combustion surfaces 21 and 22 of pellet 20 and burning of the igniter washers along the ends of pellet 20 results in combustion of the heat producing agent in the charge pellet which vaporizes the tear-producing agent. Combustion of the charge pellet and the resulting evolution of gas proceeds at both the inner and outer combustion surfaces of pellet 20 and at the upper and lower end surfaces.
It will be noted that pellet 20 is offset by rib 12 to a nonconcentric position in canister 10. This offset position produces an open space between the outer surface of the pellet and the inner wall of canister 10. In the portion of outer combustion surface 22 and the end surfaces of the pellet adjacent this open space combustion proceeds somewhat more rapidly than in the areas on the opposite side of the pellet. This is partially compensated, however, by the placement of the crack 23 diametrically opposite the rib 12. Combustion proceeds more rapidly in the area of the crack 23 due to the increased surface area provided by the crack. The combination of the exposed outer combustion surface on pellet 20 adjacent rib 12, the radial combustion surface defined by crack 22 on the opposite side of the pellet, the inner combustion surface 21 and the end surfaces of the pellet provide large areas for combustion. A large volume of gas is thus evolved quite rapidly from several exposed surfaces of the pellet.
The gas passes from the surface where it is evolved in both directions to exit from the emission holes 16 at the top and bottom of canister 10. The gas evolved at the outer combustion surface adjacent rib 12 is free to pass without obstruction to the emission holes 16 and is thus disseminated particularly rapidly. The gas is cooled slightly by contact with the interior surface of the can adjacent rib 12. The gas produced at the inner combustion surface of pellet 20 passes also toward both ends of the canister and is cooled slightly as it passes through either screen cylinder 17 or screen cylinder 30. The screen cylinders also serve to filter burning particles or fragments of any significant size. The gas produced in crack 23 and at the outer combustion surface 22 adjacent crack 23 passes primarily through screen washers 26 and 27 to emission holes 16 at the top and bottom of the can. Most of the gas evolved from the end surfaces of the pellet passes through one or the other screen washer 26, 27. The screen washers cool the gases passing through them and filter fragments and burning particles.
Thus, in the present grenade the evolution of gas occurs simultaneously from several different areas of the charge pellet, some of the gas being disseminated quite rapidly with relatively little filtering and cooling for rapid effect. The gas from other areas is disseminated less rapidly but is cooled to a greater extent so that it will diffuse more slowly and hover close to the ground for a substantial time period. The combination of these characteristics in the same grenade produces a riot control device that is extremely effective in producing both immediate effects to eliminate the possibility of "throwback" and lingering effects to fully accomplish its purpose.
Should the emission holes 16 become constricted to any appreciable extent pressure will naturally build up within the canister. In some prior grenades such pressure build-up could result in the forceful projection of particles or fragments, which could be flaming or at least hot, from the grenade at very high speeds. Serious and undesired injuries could result. In the present grenade, however, such pressure build-up is limited by the pressure relief opening 15a.
In a particular example of the grenade according to the present invention the height of canister 10 from bottom to top 14 was about 43/8 inches and the canister had an interior diameter of 23/8 inches. The can thickness was about 0.015 inches and was formed of tinned steel. The rib 12 extended inwardly about 1/8 inch. The screen cylinders 17 and 30 were about 1/16 inch thick and 15/16 inches in height and had a diameter of about 17/8 inches. The screen was No. 8 mesh tinned steel. Screen washers 26 and 27 were 1/16 inch thick and 2 5/16 inches in diameter with a central opening approximately 3/4 inch in diameter. The washers were made of tinned steel.
The composition of the charge pellet 20 was a mixture of 30% potassium chlorate, 30 percent powdered sucrose, 15 percent hydrated aluminum silicate and 25 percent orthochlorobenzalmalononitrile. As completed the charge pellet was 2 1/4 inches high with a 2 1/4 inch diameter and a central opening approximately 3/4 inches in diameter. The inner igniter tube 32 was muslin cloth impregnated with a mixture of 54 percent potassium nitrate, 37 percent silicon, 6 percent charcoal and 3 percent gum arabic, and was 4 3/8 inches in height. Tube 32 had an exterior diameter of about 3/4 inches and a thickness of about 1/16 inches. The outer igniter tube 24 had an inner diameter of about 2 1/4 inches and was about 2 1/4 inches in height. Tube 24 had a thickness of about 1/32 inch. The outer igniter tube and the igniter washers were made of the same material as the inner igniter tube. The inner and outer igniter tubes and the igniter washers were prepared by soaking muslin cloth strips of the proper size in a water slurry of the mixture of potassium nitrate, silicon, charcoal and gum arabic and then forming the strips. The igniter washers were each about 2 1/4 inches in diameter and about 1/32 inch thick. Four emission holes 15 approximately 1/4 inch in diameter were spaced symmetrically along each of the top and bottom peripheries of the canister with the hole centers being about 178 inch from the ends of the canister. Fuze 37 was a standard military M201A1 fuze modified by the addition of a terminating composition 44 which consisted of a stoichiometric mixture of fine aluminum powder and cupric oxide in a nitrocellulose matrix.
While a preferred form of the present invention has been disclosed herein it will be apparent to those skilled in the art that modifications and improvement may be made in the form herein specifically disclosed without departing from the spirit and scope of the invention. Accordingly, this invention is not to be limited to the form specifically disclosed herein nor in any other way inconsistent with the progress in the art promoted thereby.
This invention relates to grenades for the dispensing of riot control agents, particularly tear-producing gases, and to improvements in such grenades.
Chemical agents employed for riot control and similar purposes are usually the so-called tear gases, particular examples being those commonly known as CN and CS. The effectiveness of such agents for these purposes is determined not only by the characteristics of the agents themselves but also by the means by which they are disseminated which is, typically, a grenade. For effective use of the tear gas grenade as a riot control means it is desirable that there be rapid dissemination of the tear-producing agent both to obtain a rapid riot control result and also to prevent "throwback" of the grenade. Throwback occurs when the grenade can be picked up and hurled back before sufficient tear-producing agent has been emitted in a proper pattern to nullify such a reaction.
Another desirable characteristic is that the tear-producing agent itself, once disseminated, have a minimum tendency to diffuse. The agent should tend to hover close to the ground for a substantial time. Along with rapid dissemination and minimum tendency to diffuse of the tear-producing agent it is desirable for humanitarian reasons to avoid injury or mutilation such as by flying fragments or burning particles emitted from the grenade. These characteristics are determined in substantial part by the manner and rate at which the tear-producing gas is generated which, in turn, are determined by the characteristics of the grenade elements and their arrangement to form the grenade.
In a typical tear gas grenade presently in use the chemical or tear-producing agent is mixed with a heat generating material such as smokeless powder and the mixture is pressed into a can. The top surface of the mixture is covered with a slurry of priming material and a fuze is provided in the top of the canister. In operation, the fuze ignites the priming materials which in turn ignite the heat-generating material. Heat from the heat-generating material volitalizes the chemical agent. The surface area provided for ignition of the priming materials and volitalization of the chemical agent is rather limited so that the dissemination of tear-producing agent is not as rapid as desired while the tear-producing agent that is produced is disseminated at such a high temperature that it is very light and tends to diffuse.
SUMMARY OF THE INVENTION
It is a general object of this invention to provide a grenade adapted for the dissemination of tear gas or similar non-lethal riot control agent that is improved over grenades of the same type presently in use. A particular object is the provision of such a grenade that provides more rapid dissemination of tear-producing agent while substantially eliminating the emission of flying fragments and burning particles.
Another object is the provision of such a grenade in which the emitted tear-producing gas has minimum tendency to diffuse and tends to hover close to the ground for substantial periods of time.
Still another object of this invention is the provision of an improved fuze for such a grenade which provides greater ignition reliability.
A preferred embodiment of the present invention includes a canister having gas emission holes adjacent opposite ends thereof. A tubular charge having radially spaced inner and outer combustion surfaces is supported in the canister spaced from opposite ends thereof. An inner charge igniter tube extends through the tubular charge in close contact with the inner combustion surface and an outer charge igniter tube is disposed about the outer periphery of the charge in close contact with the outer combustion surface. An igniter washer is positioned on each end surface of the tubular charge and provides an ignition path between inner and outer igniter tubes. Fuze means is provided in the canister adjacent the inner charge igniter tube for igniting it. The igniter washers are ignited from the inner tube and ignite the outer igniter tube. Combustion of the igniter washers and tubes effects evolution of gas from both the inner and outer combustion surfaces and the end surfaces of the charge.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a vertical sectional view of a tear gas grenade embodying the present invention.
FIG. 2 is a sectional view of the grenade of FIG. 1 along the line 2--2 thereof.
FIG. 3 is a perspective view of the tubular charge pellet of the grenade.
FIG. 4 is a perspective view of one of the screen cylinders of the grenade.
FIG. 5 is a perspective view of one of the screen washers of the grenade.
FIG. 6 is a perspective view of the outer igniter tube of the grenade.
FIG. 7 is a perspective view of the inner igniter tube of the grenade.
FIG. 8 is a perspective view of an igniter washer.
FIG. 9 is a diagrammatic view of the grenade top illustrating the extent of the marginal safety release opening in the grenade.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A grenade according to the present invention includes a canister 10, preferably formed of metal such as tinned steel, and having a flange 11 extending around its open top. A rib 12 extends inwardly from the inner surface of the canister through its full length. A top 14 has a peripheral lip 15 which is crimped to the canister so as to form a marginal pressure relief opening 15a between the top and the flange 11. A number of emission holes 16 are provided in the canister adjacent its top and bottom which permit the escape of tear-producing gas.
The grenade elements are arranged in canister 10 as shown in FIG. 1. Positioned in the bottom of the canister is a spacing and support means in the form of a screen cylinder 17. Screen cylinder 17 is preferably about 1/2 to 3/4 of the diameter of canister 10 and formed of steel wire mesh. The screen cylinder serves as a supporting and spacing element and as a filter and cooling element as will be described below. Supported by and above screen cylinder 17 is a tubular charge pellet 20. Pellet 20 may be a mixture of one of the usual tear-producing agents such as that commonly known as CS or that known as CN, with a heat generating material such as smokeless powder. The mixture is molded into a tubular pellet as shown in FIG. 3 having an inner combustion surface 21 and an outer combustion surface 22. The pellet is released from the mole in such a manner as to produce a radial crack 23 which runs the length of the pellet between the outer and inner combustion surfaces. Crack 23 is preferably only a "hair-line" crack but assists greatly in promoting combustion of pellet 20.
Positioned about the outer combustion surface of pellet 20 in close contact therewith is an outer igniter tube 24 which may be made of fabric such as muslin which has been soaked in a solution to impart the proper pyrotechnic characteristics thereto. Igniter washers 25, 25a are positioned on opposite end surfaces of pellet 20 and overlap the outer igniter tube 24. The igniter washers are also preferably made of muslin and treated in the same manner as the outer igniter tube.
Screen washers 26 and 27 are positioned over the igniter washers on the upper and lower end surfaces of pellet 20. The screen washers distribute the weight of pellet 20 over the end surfaces thereof and act as supporting elements for the pellet, igniter washers and outer igniter tube. The screen washers 26 and 27 also serve as filters in a manner to be described below. Seated on the upper screen washer 26 is a second screen cylinder 30 which is identical to screen cylinder 17 and performs an identical function. An inner igniter tube 32 extends the length of the can, passing through the central opening in pellet 20 in close contact with igniter washers 25 and 25a and with inner combustion surfaces 21 and through screen washers 26 and 27 and screen cylinders 17 and 30. Inner igniter tube 32 is identical in material and treatment to outer igniter tube 24 and the igniter washers and has substantially the same purpose as to inner combustion surface 21 that the outer igniter tube and igniter washers have as to outer combustion surface 22 and the end surfaces of pellet 20.
In the top 14 of the grenade is a brass ferrule 34 having inner threads to receive a fuze 37. Fuze 37 may be a standard military M201A1 fuze but preferably is a fuze of that type modified according to the present invention to improve its ignition characteristics for cooperation with the igniter tubes and igniter washers. Fuze 37 includes a body 39 having an opening 40 therein to receive a series of chemical compositions indicated at 42a, 42b, and 42c forming a pyrotechnic train 42. The pyrotechnic train 42 determines the characteristics of the fuze such as delay time and the combustion intensity of the flash imparted to the inner igniter tube 32. As modified according to the present invention the pyrotechnic train is terminated with a composition 44 which has a booster effect along with the terminating composition employed in the unmodified M201A1 fuze. The characteristics of terminating composition 44 make it particularly suitable for use in igniting materials of the comppsition of igniter tubes 32 and 24 and igniter washers 25, 25a. Terminating Composition 44 consists of a stoichiometric mixture of fine aluminum powder and cupric oxide in a nitrocellulose matrix.
At the top of the pyrotechnic train 42 is a conventional percussion cap 46 which is adapted to be struck by a conventional firing pin 47 and provides a spark to initiate combustion in the pyrotechnic train 42. The firing pin 47 is normally retained in the cocked position by a lever 49 and a safety pin 50 which holds both the firing pin 47 and lever 49 in their normal positions.
The grenade is assembled by first inserting screen cylinder 17 into the bottom of canister 10. Screen washer 27 is then placed over the screen cylinder. Pellet 20 and the igniter tubes and washers will have been formed previously. The outer igniter tube 24 is preferably positioned about the exterior of the pellet in close contact with the outer combustion surface. Lower igniter washer 25a is placed on lower screen washer 27. The combination of pellet and outer igniter tube is then placed on the lower igniter washer. Preferably, the pellet is oriented so that crack 23 is diametrically opposite rib 12 for reasons described below. Upper igniter washer 25 is then placed over the upper end surface of pellet 20 and overlaps outer igniter tube 24. Upper screen washer 26 is next positioned over igniter washer 25. Upper screen cylinder 30 is then seated on upper screen washer 26 and inner igniter tube 32 is passed through the central openings in pellet 20, igniter washers 25 and 25a and screen washers 26 and 27 to the bottom of canister 10.
Top 14 including ferrule 34 is then sealed onto canister 10. The top is positioned so that the lip 15 engages the flange 11 on the canister. The canister is then placed in conventional can sealing apparatus to crimp the lip 15 over the flange and bend flange and lip downwardly. The slight pressure relief opening 15a can be formed during sealing by arranging the canister in the sealing apparatus "off center" so that unequal crimping and bending pressure is applied around the periphery of the canister and top. The result is the area 15a of less effective sealing which serves as a pressure relief opening should the emission holes 16 become too constricted. Area 15a extends through about 1/3 of the circumference of top 14 as shown at A in FIG. 8. The portion of the circumference indicated as B is that having the conventional tight sealing crimp.
Arrangement of the elements of the grenade as illustrated in the drawing provides distinct advantages compared to existing tear gas grenades in the rapid dissemination of gas and in the partial cooling thereof to prevent its rapid diffusion. In the operation of the tear gas grenade, the fuze is ignited in the conventional manner and the pyrotechnic train 42 produces the proper series of combustion steps to the terminating composition 44. The terminating composition ignites the inner igniter tube 32 which in turn ignites the upper and lower igniter washers 25, 25a. The igniter washers ignite the outer igniter tube 24 at both ends. Burning of the inner and outer igniter tubes along the inner and outer combustion surfaces 21 and 22 of pellet 20 and burning of the igniter washers along the ends of pellet 20 results in combustion of the heat producing agent in the charge pellet which vaporizes the tear-producing agent. Combustion of the charge pellet and the resulting evolution of gas proceeds at both the inner and outer combustion surfaces of pellet 20 and at the upper and lower end surfaces.
It will be noted that pellet 20 is offset by rib 12 to a nonconcentric position in canister 10. This offset position produces an open space between the outer surface of the pellet and the inner wall of canister 10. In the portion of outer combustion surface 22 and the end surfaces of the pellet adjacent this open space combustion proceeds somewhat more rapidly than in the areas on the opposite side of the pellet. This is partially compensated, however, by the placement of the crack 23 diametrically opposite the rib 12. Combustion proceeds more rapidly in the area of the crack 23 due to the increased surface area provided by the crack. The combination of the exposed outer combustion surface on pellet 20 adjacent rib 12, the radial combustion surface defined by crack 22 on the opposite side of the pellet, the inner combustion surface 21 and the end surfaces of the pellet provide large areas for combustion. A large volume of gas is thus evolved quite rapidly from several exposed surfaces of the pellet.
The gas passes from the surface where it is evolved in both directions to exit from the emission holes 16 at the top and bottom of canister 10. The gas evolved at the outer combustion surface adjacent rib 12 is free to pass without obstruction to the emission holes 16 and is thus disseminated particularly rapidly. The gas is cooled slightly by contact with the interior surface of the can adjacent rib 12. The gas produced at the inner combustion surface of pellet 20 passes also toward both ends of the canister and is cooled slightly as it passes through either screen cylinder 17 or screen cylinder 30. The screen cylinders also serve to filter burning particles or fragments of any significant size. The gas produced in crack 23 and at the outer combustion surface 22 adjacent crack 23 passes primarily through screen washers 26 and 27 to emission holes 16 at the top and bottom of the can. Most of the gas evolved from the end surfaces of the pellet passes through one or the other screen washer 26, 27. The screen washers cool the gases passing through them and filter fragments and burning particles.
Thus, in the present grenade the evolution of gas occurs simultaneously from several different areas of the charge pellet, some of the gas being disseminated quite rapidly with relatively little filtering and cooling for rapid effect. The gas from other areas is disseminated less rapidly but is cooled to a greater extent so that it will diffuse more slowly and hover close to the ground for a substantial time period. The combination of these characteristics in the same grenade produces a riot control device that is extremely effective in producing both immediate effects to eliminate the possibility of "throwback" and lingering effects to fully accomplish its purpose.
Should the emission holes 16 become constricted to any appreciable extent pressure will naturally build up within the canister. In some prior grenades such pressure build-up could result in the forceful projection of particles or fragments, which could be flaming or at least hot, from the grenade at very high speeds. Serious and undesired injuries could result. In the present grenade, however, such pressure build-up is limited by the pressure relief opening 15a.
In a particular example of the grenade according to the present invention the height of canister 10 from bottom to top 14 was about 43/8 inches and the canister had an interior diameter of 23/8 inches. The can thickness was about 0.015 inches and was formed of tinned steel. The rib 12 extended inwardly about 1/8 inch. The screen cylinders 17 and 30 were about 1/16 inch thick and 15/16 inches in height and had a diameter of about 17/8 inches. The screen was No. 8 mesh tinned steel. Screen washers 26 and 27 were 1/16 inch thick and 2 5/16 inches in diameter with a central opening approximately 3/4 inch in diameter. The washers were made of tinned steel.
The composition of the charge pellet 20 was a mixture of 30% potassium chlorate, 30 percent powdered sucrose, 15 percent hydrated aluminum silicate and 25 percent orthochlorobenzalmalononitrile. As completed the charge pellet was 2 1/4 inches high with a 2 1/4 inch diameter and a central opening approximately 3/4 inches in diameter. The inner igniter tube 32 was muslin cloth impregnated with a mixture of 54 percent potassium nitrate, 37 percent silicon, 6 percent charcoal and 3 percent gum arabic, and was 4 3/8 inches in height. Tube 32 had an exterior diameter of about 3/4 inches and a thickness of about 1/16 inches. The outer igniter tube 24 had an inner diameter of about 2 1/4 inches and was about 2 1/4 inches in height. Tube 24 had a thickness of about 1/32 inch. The outer igniter tube and the igniter washers were made of the same material as the inner igniter tube. The inner and outer igniter tubes and the igniter washers were prepared by soaking muslin cloth strips of the proper size in a water slurry of the mixture of potassium nitrate, silicon, charcoal and gum arabic and then forming the strips. The igniter washers were each about 2 1/4 inches in diameter and about 1/32 inch thick. Four emission holes 15 approximately 1/4 inch in diameter were spaced symmetrically along each of the top and bottom peripheries of the canister with the hole centers being about 178 inch from the ends of the canister. Fuze 37 was a standard military M201A1 fuze modified by the addition of a terminating composition 44 which consisted of a stoichiometric mixture of fine aluminum powder and cupric oxide in a nitrocellulose matrix.
While a preferred form of the present invention has been disclosed herein it will be apparent to those skilled in the art that modifications and improvement may be made in the form herein specifically disclosed without departing from the spirit and scope of the invention. Accordingly, this invention is not to be limited to the form specifically disclosed herein nor in any other way inconsistent with the progress in the art promoted thereby.