Patent Publication Number: US-7721651-B2

Title: Irritation member

Description:
BACKGROUND OF THE INVENTION 
   The invention relates to an irritation grenade to create irritation or shock to a human being. 
   Among other things, irritation grenades are used in hostage situations or aircraft hijackings in order to overpower the perpetrators. The irritation grenade is mainly in the form of a hand grenade with a preferably cylindrical receptacle that possesses at least one, and preferably several, chambers, e.g., drilled holes, extending parallel to the longitudinal axis and occupying the entire length of the receptacle. Said chambers contain active or effective charges such as sound or flash loads. A manually-operable igniter, usually a rocker-arm igniter, ignites a pyrotechnic delay charge that ignites the individual effect charges via ignition channels. These charges create a shock effect such as, for example, a very loud noise, a blinding flash, or similar, achieving an irritation or shock effect to the perpetrator and allowing him to be captured. 
   An irritation grenade of the type discussed above is known from WO 94/08200 in which a total of six compartments that transfix the entire length of the irritation grenade are positioned about the central axis of the irritation grenade and that are sealed by plugs at the upper and lower end, into which the particular effect charge is placed. Upon ignition of the effect charges the plugs are instantly ejected by the increasing inner pressure within the compartments, after which the combustion gases exit upward and downward from the receptacle via the now opened discharge ports. During this, recoil acting on the irritation grenade in opposing directions should be canceled out. It has been nevertheless shown, that after ignition of an effective charge, the irritation grenade may be displaced by several meters. Such an uncontrolled displacement presents the hazard of injury for any persons in the vicinity, particularly with those irritation grenades with several time-offset effects, but not only with them. 
   SUMMARY OF THE INVENTION 
   It is an object of the invention to prevent displacement after the ignition of individual effect charges, so that the irritation grenade remains in essentially the same place after striking the floor, thus not injuring bystanders by means of its displacement. 
   It has turned out that displacement of the irritation grenade after ignition of the effective charge is essentially caused by the fact that parts of the rocker-arm igniter extend into the stream of the combustion gases of the effective charges, and modify the recoil caused by the combustion gases on the irritation grenade. 
   This may be avoided per the invention in a simple manner in that the cross section of the discharge ports of the compartments at the end of the plug side opposite the igniter be made smaller than the cross section of the discharge ports on the igniter end. The ratio of discharge ports is so selected that recoil forces arising from the combustion of the effective charges act on both opposite sides of the irritation grenade essentially equally. 
   The compartments of the irritation grenade are preferably stepped drilled holes to accept the effective charges, whereby the step on the floor of the irritation grenade is provided, thus reducing the cross section of the hole there. 
   The ratio of cross sections of the discharge ports at opposite ends of the irritation grenade need not be the same for all compartments since the streams of combustion gases may be influenced differently from different compartments through the igniter. In order to achieve essentially complete balance of recoil forces in such a case, it must be ensured that the igniter is always mounted to the receptacle of the irritation grenade at the same angle. 
   For a full understanding of the present invention, reference should now be made to the following detailed description of the preferred embodiments of the invention as illustrated in the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of an irritation grenade based on the invention at an approximate scale of 1:1. 
       FIG. 2  is a longitudinal cutaway view through the irritation grenade in  FIG. 1 . 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The preferred embodiments of the present invention will now be described with reference to  FIGS. 1 and 2  of the drawings. Identical elements in the figures are designated with the same reference numerals. 
   An irritation grenade  1  includes a cylindrical receptacle  2  to accept several effective loads  3  and a rocker-arm igniter  4  mounted on the upper face of the receptacle  2  as shown in  FIG. 1 . 
   The rocker-arm igniter  4  is provided with a handgrip  5  extending almost the entire length of the receptacle  2  that may be very rapidly pivoted upward about a horizontal axis  6  above the top face of the receptacle  2  with the help of a strong pre-tensioned spring  7  as shown in  FIG. 2 . The handgrip  5  is usually secured using a securing pin (not shown), and is thus held in the initial position shown in  FIG. 2 . If the irritation grenade is used, the securing pin is removed, whereby the handgrip is held in its initial position by the user. 
   The rocker-arm igniter includes a striking pin that is moved by the spring  7  along with the handgrip  5  when it is released, and that subsequently strikes a centrally-positioned ignition cap  9 , igniting its charge. 
   From this central ignition cap  9 , a central blind hole extends along the middle axis in which a delay charge  11  is placed, ending approximately in the vicinity of the floor of the receptacle  2 . 
   Around the central drilled hole  10  compartments or chambers are positioned parallel into which the above-mentioned effective charges  3  are placed. Each of the chambers  12  is a stepped drilled hole that extends for the entire length of the receptacle  2 , and each possesses a step  13  near its floor that reduces the cross section of the chamber. 
   Each chamber  12  is sealed at its end on the opposite face of the receptacle  2  by a plug  14  or similar. 
   Ignition transfer channels  16  lead from the central chamber  10  to the individual chambers  12 , whereby these ignition transfer channels are drilled from the outside and the outer openings are subsequently sealed, e.g., by a jacket  18  on the mantle surface of the grenade. 
   Function of the irritation grenade is as follows: 
   After release of the above-mentioned security pin for the handgrip  5  and while holding the irritation grenade  1  in the hand by the handgrip, the irritation grenade  1  is thrown in the direction of a perpetrator to be irritated. When the irritation grenade is released, the striking pin  8  strikes the igniter cap  9 , igniting its charge. This charge in turn ignites the delay charge  11  within the central chamber  10 . The delay charge  11  combusts at a predetermined speed. As soon as the flame front reaches a ignition transfer channel for a chamber  12 , the effective charge  3  within the chamber is ignited. Various effects are created by the position of the ignition transfer channels  16  in the direction of the central axis of the irritation grenade: for example, the effective charges may be ignited in all chambers simultaneously or sequentially, whereby intermediary actions are possible. 
   The design of the individual chambers  12  as stepped drilled holes with a diameter D and a reduced diameter d through step  13  allows the chambers  12  to have an discharge port  21  on the side facing the rocker-arm igniter  4  with a diameter D and a discharge port  22  on the bottom side with a diameter d. The two diameters D and d are so matched to each other that the recoil impulse created by the discharged combustion gases from the effective charges  3  is the same in both directions. After the plug  14  is expelled by the inner pressure within the chambers  12  upon combustion of the effective charges  3 , impulses or recoil forces of equal magnitude are exerted on the irritation grenade in both directions so that it remains in one place and is not displaced. 
   It is clear that the diameter or general cross section of the discharge ports  21 ,  22  of different chambers  12  may also be dimensioned differently in order to balance the disruptions caused by the rocker-arm igniter individually. 
   There has thus been shown and described a novel irritation grenade which fulfills all the objects and advantages sought therefor. Many changes, modifications, variations and other uses and applications of the subject invention will, however, become apparent to those skilled in the art after considering this specification and the accompanying drawings which disclose the preferred embodiments thereof. All such changes, modifications, variations and other uses and applications which do not depart from the spirit and scope of the invention are deemed to be covered by the invention, which is to be limited only by the claims which follow.