Abstract:
The invention relates to a pneumatic mechanism actuated by specific pyrotechnic ammunition. The pneumatic mechanism is actuated by specific pyrotechnic ammunition or by blank ammunition and is characterized in that the recoil of the breech block actuates a piston which compresses air situated in a compression chamber in order to propel a lightweight paintball or plastic bead. Application to toy weapons of the “paintball” or “airsoft” type to make firing the shot more realistic.

Description:
[0001]    The present invention relates to a mechanism for a toy weapon with novel operation and in particular a pneumatic mechanism firing lightweight balls of paint or of plastic, actuated by specific pyrotechnic ammunition or by blank ammunition, designed to improve the firing realism of accelerators of the “paintball” or “airsoft” type. 
       PRIOR ART 
       [0002]    Accelerators of the “paintball” or “airsoft” type have existed for a long time. The ball can be accelerated in various ways, either by piston compressing air coupled with an electric gearing, or conventionally with the aid of a bottle of compressed air or of CO 2 . All these accelerators provide very little firing realism. 
         [0003]    For training the armed forces, there is ammunition with marking projectiles that provides more realism, amongst which are those described in patent applications WO9841810 and WO9114148, but using them requires the possession of a handgun in order to fit a conversion kit to it. 
         [0004]    Some of this ammunition is very costly in terms of use, which adversely affects the number of training sessions and consequently the quality of the action. 
       OBJECT OF THE INVENTION 
       [0005]    The object of the present invention is to design a pneumatic mechanism for a toy weapon accelerating lightweight balls of paint or of plastic, actuated by a specific pyrotechnic ammunition, that can be accessed by a wide public, is cheap in its use and provides more realistic operation than “paintball” and “airsoft” accelerators. 
         [0006]    A further object of the invention is to develop a mechanism which makes it impossible to accidentally or intentionally insert real ammunition into the chamber. It should also be specified that the choice of materials of the various parts of the mechanism prevents firing real ammunition, by using for example plastics or aluminum-based or zinc-based alloys. 
         [0007]    The subject of the invention is therefore a pneumatic mechanism actuated by specific pyrotechnic ammunition or by blank ammunition which is characterized in that the recoil of the breech block actuates a piston that compresses air situated in a compression chamber in order to propel a lightweight ball of paint or of plastic. 
         [0008]    According to a variant embodiment, the mechanism may be activated by blank ammunition. This variant considerably improves the quality of the training and it is therefore mainly designed for training the army and the forces of order. 
         [0009]    A further subject of the invention is specific pyrotechnic ammunition suitable for the above pneumatic mechanism. This ammunition is characterized in that it comprises a casing provided with several regular grooves on its front portion, a piston forced into the casing and a standard percussion cap. 
     
    
     
       DESCRIPTION OF THE INVENTION 
         [0010]    The invention will now be described with reference to the figures given by way of illustration and being nonlimiting, in order to make it easier to understand the features of the invention. 
           [0011]      FIG. 1  represents a view in section of the ammunition. 
           [0012]      FIG. 2  represents a view in section of the mechanism loaded with its specific ammunition. 
           [0013]      FIG. 3  represents the position of the various parts of the mechanism just before the specific ammunition is ejected. 
           [0014]      FIG. 4  represents a detail view in section of the rear portion of the sleeve and of the valve. 
           [0015]      FIGS. 5   a  and  5   b  represent two variant embodiments of the breech block with the piston separated from its block. 
       
    
    
       [0016]    The expressions “front” and “rear” designate respectively the front and the rear of the various parts, in the direction of firing. 
         [0017]    As shown in  FIG. 1 , the ammunition comprises:
       a casing ( 2 ) provided with 2 or 4 regular grooves ( 4 ) on its front portion. The curvature ( 8 ) or optionally a bevel makes it easier to insert the ammunition into the chamber ( 38 ) of the body ( 10 );   a piston ( 3 ), ideally made of rubber, lightly forced into the hole ( 5 ) of the casing; and   a standard percussion cap ( 1 ).       
 
         [0021]    The casing, preferably made of plastic, can be obtained by thermoforming, by molding or else even be carved from the solid piece. The piston ( 3 ) made of an elastic material, ideally of rubber, is obtained by cutting a sheet a few millimeters thick or else made by molding. 
         [0022]      FIG. 2  illustrates the mechanism loaded with its ammunition. The body ( 10 ) has the particular feature by which a pin ( 20 ) is placed concentrically in the chamber ( 38 ) in which the ammunition is housed. Preferably, this pin is molded with the body and it is made so that its face ( 32 ) does not hamper the insertion of the ammunition. When the ammunition is loaded into the chamber, the front face of the piston ( 6 ) does not touch the face ( 32 ) of the pin ( 20 ). 
         [0023]    When the firing pin ( 22 ) strikes the percussion cap ( 1 ) of the ammunition, a pressure is created in the cavity ( 9 ) of the casing ( 2 ) pushing the piston ( 3 ) forward. The face ( 6 ) of the piston then comes into contact with the face ( 32 ) of the pin ( 20 ) and gradually as the pressure increases, the casing ( 2 ) recoils pushing the breech block ( 21 ) rearward with sufficient force to actuate the system. The combination of the pin ( 20 ) and of the specific pyrotechnic ammunition has the particular feature that the pyrotechnic ammunition of the invention develops sufficient force to actuate the mechanism, that is to say the complete recoil of the breech block necessary for the pneumatic operation and automatic reloading with ammunition of the mechanism, with only a standard percussion cap, with no additional powder. 
         [0024]    The pressure generated by the percussion cap pushes the piston ( 3 ) of the ammunition until its rear face ( 7 ) protrudes beyond the bottom of the grooves ( 11 ) of the casing. The pressure then escapes through these grooves and when all the pressure has escaped, the piston ( 3 ) stops its movement and remains inside the hole ( 5 ) of the casing. 
         [0025]    According to one feature of the invention, during the recoil of the breech block, the piston ( 24 ) secured to the breech block ( 21 ) recoils at the same time and compresses the air situated in the compression chamber ( 26 ) toward the inlet chamber ( 27 ). 
         [0026]    The dimensions of the compression chamber vary depending on the desired power. 
         [0027]    According to one variant embodiment of the breech block, this piston may be separated from the breech block. A compression spring ( 13 ) is inserted into the chamber in order to allow the piston to perform its function, that is to say to return to the initial position after having compressed the air in the compression chamber ( 26 ). This spring is ideally conical in order to allow the piston to carry out a sufficient travel necessary for accelerating the ball. Note in  FIG. 5   a  that, by virtue of this spring, the face ( 14 ) of the piston ( 24 ) remains in contact with the face ( 15 ) of the breech block ( 21 ). 
         [0028]    According to another variant embodiment represented by  FIG. 5   b , a ring ( 16 ) screwed or force-fitted into the chamber of the body can hold the piston in this chamber and, when the breech block recoils, the face ( 15 ) will come into contact with the face ( 14 ) of the piston ( 24 ), pushing the latter in order to compress the air in the compression chamber ( 26 ). 
         [0029]    When the air pressure reaches a sufficient level to overcome the resistance of the spring ( 41 ), the valve ( 48 ) moves the ball ( 31 ) forward and directs it toward the barrel. The valve ( 48 ) is ideally made of aluminum carved from the solid piece and slides in the bore ( 60 ) of the sleeve ( 42 ). The sleeve may also be made of aluminum or any other alloy having the desired mechanical characteristics. 
         [0030]    As shown in  FIG. 4 , two or four regular grooves ( 33 ) are provided on the rear portion of the sleeve ( 42 ). The rear portion of the valve ( 48 ) has the same number of open-ended holes ( 34 ) that are preferably oriented in the same direction as the grooves ( 33 ) of the sleeve ( 42 ). 
         [0031]    Therefore, when the valve is moved forward, the holes of the valve and the grooves of the sleeve will interact to form a channel and discharge the compressed air in order to propel the ball in the barrel. At the end of travel, the valve is closed at the end of its translation by virtue of a closing system. 
         [0032]    This closing allows, on the one hand, the return of the breech block for reloading with ammunition, and, on the other hand, the filling of the chamber ( 26 ) with air. A recoil spring (not shown) helps with the return of the breech block. 
         [0033]      FIGS. 2 and 3  show an exemplary embodiment of the closing system. This system consists of the strip ( 83 ) to which two pins ( 84 ,  85 ) are crimped and of a tension or compression spring (not shown) which presses the system toward the body ( 10 ). The pins ( 84 ) and ( 85 ) slide in the bores of the body ( 10 ), respectively ( 86 ) and ( 87 ). 
         [0034]    A hole ( 88 ) provided on the sleeve ( 42 ) allows the pin ( 84 ) to hold the sleeve ( 42 ) in the body ( 10 ) and to communicate with the flat ( 90 ) of the valve ( 48 ) in order to actuate the closure. 
         [0035]    When the breech block ( 21 ) recoils, the front portion ( 93 ) of the pin ( 91 ) separates from the front ( 94 ) of the pin ( 85 ), the face ( 95 ) of the pin ( 84 ) then presses against the external diameter of the valve ( 48 ) and, when the latter translates, the face ( 95 ) rubs on the external diameter of the valve until the flat ( 90 ) is reached. 
         [0036]    The closing of the valve is thus established when the face ( 95 ) of the pin ( 90 ) comes into contact with the face of the flat ( 90 ). When the breech block returns, the front portion ( 93 ) of the pin ( 91 ) enters the hole ( 76 ) of the body ( 10 ) and causes the translation of the pin ( 85 ). The face ( 95 ) of the pin ( 84 ) then leaves the flat ( 90 ) and, by virtue of the spring ( 41 ) the valve ( 48 ) returns to its initial position. A new ball is then placed in the acceleration chamber ( 44 ). 
         [0037]    The portions ( 94 ) and ( 93 ) have a shape that is appropriate for the pin ( 91 ) to communicate the translation to the pin ( 85 ). 
         [0038]    When the breech block ( 21 ) returns, conventionally performed by a recoil spring (not shown), the front portion ( 93 ) of the pin ( 91 ) enters the hole ( 76 ) of the body ( 10 ) and causes the translation of the pin ( 85 ). The face ( 95 ) of the pin ( 84 ) then leaves the flat ( 90 ) and, by virtue of the spring ( 41 ) the valve ( 48 ) returns to the initial position; a new ball is then placed in the acceleration chamber ( 44 ). 
         [0039]    While the breech block returns, new ammunition is placed in the chamber ( 38 ). 
         [0040]    The cycle described in the preceding phases is repeated until there is no more ammunition. Ideally the amount of ammunition corresponds to the number of balls. Depending on the desired power, the mechanism may have a body having several compression chambers ( 6 ) and consequently a breech having the corresponding number of pistons ( 24 ). 
         [0041]    According to another variant embodiment, the pneumatic mechanism may be actuated by blank ammunition. This variant, that is well suited to army training, is based on the same principle, that is to say a piston which may or may not be secured to the breech block, compresses the air in a compression chamber in order to propel a lightweight ball of paint or of plastic. The system therefore has no pin ( 20 ) but has a duct for discharging the gases given off by the blank ammunition.