Patent Publication Number: US-2016238357-A1

Title: Hand grenades

Description:
CROSS REFERENCE 
     This application claims priority under 35 USC §119 to British Patent Application No. 1502600.8 filed Feb. 17, 2015, which application is hereby incorporated by reference in its entirety. 
     FIELD OF THE INVENTION 
     This invention relates to hand grenades and is concerned with the provision of a novel form of blank-firing hand grenade. 
     More specifically, the invention is concerned with the provision of a blank-firing hand grenade which is reusable and can be used for training purposes in the carrying out of “Airsoft” or “Paintball” games. 
     BACKGROUND OF THE INVENTION 
     Normal hand grenades with safety levers are unsuitable for these games as the levers can easily be lost. In addition, many hand grenades are too heavy and dangerous to use against civilian players. 
     Hand grenades with a pyrotechnic delay are usually expensive to use and inappropriate in that the delay gives the opposing players time to kick the grenade away before detonation occurs. 
     SUMMARY OF THE INVENTION 
     According to the present invention there is provided a hand grenade that includes a main body, a receiver holding a cartridge chamber, a firing pin that acts in the manner of a pendulum and a ball located between facing conical surfaces on the firing pin and on a wall of the main body. 
     The diameter of the lower portion of the firing pin is preferably substantially greater than the diameters of the upper and central parts of the firing pin. The firing pin thus has a relatively low centre of gravity. 
     One end of the firing pin is preferably positioned in a hole in the receiver with a spring acting between the receiver and the firing pin. 
     The arrangement is such that a safety ring-pin can be inserted in the hole in the receiver to prevent inadvertent movement of the receiver relative to the main body, the safety ring-pin being removed before throwing of the grenade. 
     The arrangement is preferably such that the receiver is free to move vertically within limits and to rotate when the safety ring-pin is removed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a sectional view of a hand grenade, and 
         FIG. 2  is another sectional view of the hand grenade, taken at right angles to  FIG. 1 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The hand grenade shown in the drawings includes a generally cylindrical main body  10  made from, for example, a relatively light-weight polymeric material. The inner surface  8  of the base of the main body  10  is of conical form and a ball  7  rests on the conical surface  8 , being trapped between the conical surface  8  and the inverted conical surface  9  of the base of a pendulum type firing pin  6  contained within the cylindrical interior of the main body  10 . As can be seen from  FIG. 1 , the diameter of the lower part of the firing pin  6  is substantially greater than the diameters of the upper and central parts of the firing pin  6 , which thus has a relatively low centre of gravity. 
     A receiver  3  made from, for example, aluminium is positioned within the open end of the main body  10  and has an outwardly facing annular channel within which is located a wire ring  11  secured to the inner surface of the main body  10 . Movement of the receiver  3  is prevented when a safety ring-pin  13  is in place. The safety ring-pin  13  is fitted in a hole in the wall of the main body  10 . The receiver  3  is formed with a cylindrical recess in which a cartridge chamber  2  is located and the cartridge chamber  2  has a flash ejection hole  1 . The safety ring-pin  13  (when inserted in the hole) rests on a shoulder of the firing pin  3  and serves to prevent the firing pin  6  from reaching the cartridge  14  within the chamber  2 . It also prevents the receiver  3  from moving downwards and from revolving when the cartridge chamber  2  is being screwed into position or unscrewed. 
     A spring  5 , of generally conical configuration as shown in the drawing, acts between the underside of the receiver  3  and a shoulder of the firing pin  6  to hold the firing pin  6  down and the receiver  3  up, thus urging the firing pin  6  away from the primer of the blank cartridge  14  positioned within the chamber  2 . As the firing pin  6  is supported on the ball  7 , which is positioned between two facing conical surfaces  8  and  9 , and as the diameter of the lower portion of the firing pin  6  is substantially greater than the upper portion of the firing pin  6 , the firing pin  6  will operate in a manner corresponding to a pendulum. 
     Before the grenade is thrown, the ring pin  13  is removed from the hole. 
     If the throwing of the grenade results in its base striking a hard surface, the receiver  3  will move downwardly under the action of gravity so that the blank cartridge  14  in the cartridge chamber  2  will be thrust against the top of the firing pin  6  and the cartridge  14  will be fired. 
     If the grenade lands the other way up, the receiver  3  will move inwardly against the action of the spring  5  and the cartridge  14  will again be fired. 
     If, however, the grenade lands on its side, the pendulum-action firing pin  6  will move towards the side of the body  10  that has engaged the ground but, because the firing pin  6  is engaged with the ball  7 , the effect of the ball  7  rolling in engagement with the two conical surfaces  8  and  9  will result in the firing pin  6  moving towards the blank cartridge  14  and firing it. 
     Thus, whatever the orientation of the grenade when it strikes the ground, the cartridge will be fired. The grenade can thus be used for training purposes or in “Airsoft” or “Paintball” games.