Launchable flameless expulsion grenade

The present invention relates generally to tear gas grenades and, more particularly, tear gas-type grenades using as the expulsive force compressed gas such as CO 2 which, unlike a pyrotechnic, is flameless and thus provides a correspondingly flameless use.

The use of expulsive Carbon Dioxide (CO 2 ) tear gas grenades are well known because the expulsion is flameless due to the use of CO 2 , as distinguished from a pyrotechnic expulsive fuel which burns hot and may shoot out white hot slag, one such flameless CO 2 tear gas grenade being that described and illustrated in U.S. Pat. No 5,069,134 for “Flameless Expulsive Grenade” issued to Pinkney on Dec. 3, 1991.

The '134 tear gas grenade and all other known similar grenades benefit from a flameless expulsion due to the use of CO 2 for the tear gas formulation which is normally in powder or liquid form, but in the absence of delicate handling prior to use and/or careful control during use, these grenades are vulnerable to premature release of the CO 2 and thus a tear gas consequence at an unwanted non-target area location.

Broadly, it is an object of the present invention to provide a flameless CO 2 tear gas grenade overcoming the foregoing and other shortcomings of the prior art.

More particularly, it is an object to release the CO 2 for its expulsive effect following a piercing of its storage container caused by use of an expanding and contracting pyrotechnic-produced gas, but under safe and controlled circumstances which maintains its flameless nature, and in which the gas expansion for container piercing and subsequently contraction for CO 2 release from the pierced container entails a time interval which obviates any premature tear gas consequence until completion of the trajectory of the grenade at the target area, all as will be better understood as the description proceeds.

The description of the invention which follows, together with the accompanying drawings should not be construed as limiting the invention to the example shown and described, because those skilled in the art to which this invention appertains will be able to devise other forms thereof within the ambit of the appended claims.

FIG. 1 is a front elevational view, partially in longitudinal cross section, of a prior art grenade using pressurized carbon dioxide (CO 2 ) as the expulsive force to achieve a tear gas consequence at a target area;

FIGS. 2, 3 and 4 are front elevational views, in longitudinal cross section, illustrating in sequence an operating mode of a tear gas expulsive grenade addressing the problem of premature release of the CO 2 of the prior art and like grenades of FIG. 1, in which more particularly, FIG. 2 depicts the grenade prior to use;

FIG. 3 depicts the grenade at an initial location in its trajectory to a target area; and

FIG. 4 depicts the grenade subsequently along its trajectory at a location adjacent its target area.

As background, it is noted that tear gas grenades of the flammable or pyrotechnic type have been in use for some time. Pyrotechnic grenades include a fuel used to ignite tear gas pellets which produce a smoke that is expelled through ports in the grenades. A major drawback in using pyrotechnic grenades is that they burn quite hot and can readily start fires. Accordingly, their use is generally limited to locations where there is no fear of igniting combustible materials.

A tear gas grenade having a more desirable flameless explosive force instead of a pyrotechnic fuel uses pressurized carbon dioxide (CO 2 ) and in FIG. 1 is generally designated 10 . The source 12 of the CO 2 is stored for use within a container 14 mounted in relation to the direction of launch or its trajectory 16 , in an upside down orientation in which a bottom closure 18 of the container 14 is in a clearance position below a closure piercing component 20 . In the pre-launch handling of the prior art grenade 10 inadvertent dropping of the unit on its base 22 or, even more significant, a sudden acceleration immediately after launch will cause movement 24 in the housing 26 not also occurring in the CO 2 container 14 , due to its inertia and being held stationary in the housing 26 between spring 28 and rear positioning wad 30 , which will cause premature piercing contact of the piercing component 20 with the bottom closure 18 and thus a corresponding premature release of the CO 2 .

The problem of premature release of the CO 2 is addressed in the operating mode illustrated in sequence in FIGS. 2, 3 and 4 to which reference should now be made. The tear gas grenade, generally designated 32 , preparatory to use, is held securely in hand and this results in a lever 34 being restrained by the palm of the hand. A safety pin 36 is removed by pulling on a ring 38 and the grenade 32 is thrown.

Once free, the lever 34 under spring urgency flies off and results in a sequence of occurrences, well understood in the munitions art of:

(1) allowing a striker to hit a primer that initiates a pyrotechnic delay column;

(2) after a prescribed delay (usually 1.5 seconds), a fuse shoots out white hot slag and flame into a baffle cavity;

(3) slag and flame emerging from a small hole in a baffle disc which ignites a propelling charge; and

(4) the stock and expanding gasses from the ignited charge provide the operating mode in the grenade 32 which uses the pressurized CO 2 as the expulsive force in causing a tear gas consequence at a target area.

To advantageously use the aforesaid well known sequence of occurrences to obviate premature release of the CO 2 which provides the expulsive force for grenade 32 , the grenade 32 is constructed, as will now be described in conjunction with FIGS. 2, 3 and 4 , with significant differences noted from the construction of prior art tear gas grenades, as exemplified by grenade 10 of FIG. 1 . More particularly, in the housing 40 of the grenade 32 there is provided a source 42 of pressurized CO 2 within a container 44 mounted, relative to its direction of launch 46 , in a right-side up orientation, thereby positioning a top closure 48 of pierceable construction material, from which the container 44 is suspended in descending relation in the housing 40 in a clearance position below a piercing component 50 , or in a reverse relationship of that of the prior art grenade 10 of FIG. 1 .

Piercing component 50 has a circular disc-like body 52 sized to have a friction fit at the interface 54 of its peripheral edge and a cylindrical wall 56 bounding a tracking compartment 58 for the piercing component 50 during descending movement 60 from its clearance position above the container top closure 48 , said descending movement 60 resulting under the urgency of expanding gas, depicted at 62 , dislodging the piercing component from its friction fit 54 into piercing contact of its integral pointed projection 64 into the top closure 48 . The expanding gas 62 , in turn, is the result of ignition of a propelling pyrotechnic charge 66 .

At the base of the tracking compartment cylindrical wall 56 are side venting openings 68 and 70 in communication via an external clearance 72 about the container 44 and spaced from a frangible latex or rubber membrane housing 74 . Housing 74 protects the CO 2 container 44 and internal components from contamination and possible adverse effects of a payload 76 in the grenade housing 40 , such as tear gas-producing powder or the like known to cause oxidation.

It will be noted that the piercing component 50 comes to a full stop against the container top closure 48 and in that position the disc body 52 closes the venting openings 68 and 70 thus preventing any flame or hot gases 62 from escaping through the venting openings 68 and 70 and having flow communication via the clearance 72 causing premature rupturing of the membrane housing 74 .

As the gasses 62 above the piercing component 50 cool and contract, pressure above the piercing component subsides. Simultaneously, pressure released from the pierced CO 2 container 44 builds under the piercing component body 50 eventually forcing it to partake of ascending movement 78 unblocking venting openings 68 and 70 and resulting in the CO 2 pressure blowing through one or more membrane openings, such as opening 80 , as depicted at 82 , with the result of serving as an effective expulsive force expelling, as at discharge openings, such as opening 84 , and as depicted at 86 , as well as through additional openings 88 , the tear gas powder 76 .

In practice, it has been found that the sequence of events initiated by the fuse entails a time interval resulting in the grenade 32 being at a location in its trajectory which is adjacent its intended target area, thus obviating any adverse consequence as might occur upon premature release of the CO 2 being used as the expulsive force of the grenade.

While the apparatus for practicing the within inventive method, as well as said method herein shown and disclosed in detail is fully capable of attaining the objects and providing the advantages hereinbefore stated, it is to be understood that it is merely illustrative of the presently preferred embodiment of the invention and that no limitations are intended to the detail of construction or design herein shown other than as defined in the appended claims.