Abstract:
In the related art, impact on an inner barrel is strong, and functions as resistance, and each member is likely to be damaged because the biasing force of the retainer spring is strong. 
     In order to solve the problems, there is provided an air gun in which the backward movement of an inner barrel  10  causes high-pressure gas to be injected into the inner barrel from a gas chamber  15,  and a bullet W is projected after the inner barrel  10  has advanced towards the muzzle, the retainer  7  which retains a bullet W supplied from a magazine  16  can rotate in a direction towards the rear of the gun from the position where a bullet W is held, about the retainer rotational axis  70,  a bullet abutment part  73  abuts on and holds the bullet W, and retention of a bullet W is released by the backward rotation with the movement of the inner barrel  10  towards the rear side of the gun.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    This invention relates to an air gun (air-powered gun). More specifically, the invention relates to an air gun with a retainer for retaining a bullet which moves from a magazine to a propulsion position of an inner barrel. 
         [0003]    2. Description of the Related Art 
         [0004]    An air gun in this technical field is an air gun where an inner barrel advances in the direction of a muzzle, then the inner barrel retreats to hit a valve, high pressure gas is injected from a gas chamber to the inner barrel by the movement of the valve, and a bullet is discharged. 
         [0005]    An air gun having this mechanism is disclosed in U.S. Pat. No. 4,147,152 (related art 1). In this air gun a magazine  20  is placed above an inner barrel  72 , and bullets in the magazine  20  are supplied from a loading port  294  to a retainer  160  which is situated under an inner barrel. The retainer  160  is positioned facing the lower part of the loading port  294 . The retainer is an elastic body made of a rod-like member inflected. A bullet is supplied to the concave portion of the retainer  160  and retained. 
         [0006]    In the related art 1, in order to shoot a bullet, a shooter should push a lever by hand to advance the inner barrel  72  in the direction of the muzzle, the loading port  294  is opened, a bullet in the magazine  20  drops into the inner barrel  72 , is retained in the retainer  160 , and the bullet is shot by pulling a trigger. 
         [0007]    Another air gun (related art 2) with a retainer has been disclosed as shown in  FIGS. 22 through 25 . Also in the air gun disclosed in the related art 2, a magazine  100  is placed upper part of an inner barrel  102 . A bullet W is urged in a direction of the rear side of the air gun by a magazine spring  101 . Normally, it is abutted on the upper surface of a tube of the inner barrel  102  and resting. When the bullet W is shot, the inner barrel  102  moves in the direction of a muzzle. After the bullet W is shot, a next bullet drops into a chamber  103  through a magazine loading port placed on the chamber  103 . The bullet W dropped in the chamber  103  is retained by a retainer  104  placed at a position opposed to the magazine loading port and biased by a magazine spring  101 . 
         [0008]    The retainer  104  disclosed in the conventional technology 2 consists of a tube whose upper part is a circular truncated cone, which is biased upward with a retainer spring  105 . The upper end of the retainer  104  is formed as a circular opening. The configuration is such that the circular opening pushes upwards and retains the bullet supplied into the chamber  103 . 
         [0000]    Patent document 1: Patent publication of U.S. Pat. No. 4,147,152 (art 1) 
         [0009]    However, the retainer disclosed in the conventional technology 1 is positioned situated under an inner barrel. The retainer ( 160 ) is positioned at the lower part of the inner barrel and an elastic body with a concave part made of a rod-like member that is inflected. Therefore, the retainer has a problem that it cannot reliably retain a bullet. 
         [0010]    Additionally, in the air gun in the conventional technology 2 the retainer  104  is biased upwards by a retainer spring  105  so that a bullet W positioned at the circular opening is pushed upward. In other words, the bullet is pushed at right angles to the movement of the inner barrel  102 . At the same time, the bullet W is pushed by the next bullet W 1  from top to bottom by the biasing force of the magazine spring  101  of the magazine  100 . Therefore, a biasing force stronger than that of the magazine spring  101  was required for the retainer spring  105 . 
         [0011]    Thus, the back-end of the inner barrel  102  comes into collision with the upper cone surface of the retainer  104  when the inner barrel  102  moves backwards in the gun, to move the retainer  104  downward, but the upward biasing force of the retainer spring  105  is strong and so the collision is strong, and acts as a resistance to make each member likely to be broken with prolonged use (see  FIG. 23 ). 
         [0012]    At the same time, the back-end of the inner barrel  102  also comes into collision with the bullet W in the chamber  103  causing resistance. If the back-end of the inner barrel  102  is deformed, it becomes difficult for the bullet W to be contained in the inner barrel  102  and the bullet cannot be shot due to bullet supply problems. (See  FIG. 24 ). 
         [0013]    Further, the upper surface of the cone surface of the retainer  104  always pushes the lower surface of the inner barrel  102  upward of the retainer spring  105  with the biasing force. Therefore, a friction resistance is generated between the upper surface of the cone surface of the retainer  104  and the inner barrel  102  causing members to deteriorate quickly (See  FIG. 25 ). 
         [0014]    When the inner barrel  102  moves backward in the gun and comes into collision with the retainer  104  and bullet W, thus reducing the recession velocity of the inner barrel  102  and reducing the force to hit the valve  107 . If the force to hit the valve  107  is reduced, the amount of gas discharged from the gas chamber  106  to the inner barrel  102  is decreased or varies so that firing speed of a bullet is reduced, or the original performance of the air gun cannot be demonstrated. 
         [0015]    As the related art 2, a bullet is supplied from the upwardly positioned magazine and retained, and so the retainer positioned below the inner barrel has a relatively large size in order to hold the strong upward biasing force, and the retainer positioned above the inner barrel is unnatural from the viewpoint of design of an air gun. 
       SUMMARY OF THE INVENTION 
       [0016]    In order to solve the above-described problems, there is provided an air gun in which an inner barrel advances in the direction of a muzzle, and then retreating movement causes high-pressure gas to be injected into the inner barrel and a bullet is projected, wherein, a retainer for holding a bullet supplied from a magazine can be rotated about a retainer rotational axis from a position where a bullet is retained in the direction of the back of the gun, a part which comes in contact with a bullet abuts against a bullet to retain it, and the movement of the inner barrel toward the back of the gun causes backward rotation to release the retention of the bullet. 
         [0017]    Additionally, an air gun mentioned in paragraph 0013 
         [0018]    above in which a retainer can retain a bullet positioned in a chamber by substantially aligning the center of the bullet with the center of the tube of the inner barrel is proposed. 
         [0019]    According to the present invention, the impact against the retainer by the backward movement of the inner barrel is deflected and cushioned by the rotation of the retainer. Therefore, the retainer functions less as a resistance, there is less damage to the retainer and inner barrel, the endurance of the air gun is improved, and the performance of the air gun as a gun is improved. 
         [0020]    The retainer rotates backward, then moves to the upper part of the inner barrel and slides on the upper surface of the inner barrel. However, the friction resistance is small so the performance of the air gun as a gun is improved. 
         [0021]    In the invention according to claim  2 , the retainer holds a bullet with the center of the bullet substantially aligned with the center of the tube of the inner barrel during the period from advancement and backward movement so that the inner barrel does not come into collision with a bullet when the inner barrel moves backward and the bullet does not function as resistance. As a result, the impact force of the inner barrel to hit the valve, and thus the speed of the bullet, is made stable and the performance of the air gun is improved. 
         [0022]    With this invention, differing from the related art 2, a bullet is retained by the rotating biasing force and members can be downsized so that a retainer can also be placed above the inner barrel. Therefore, an air gun in which a magazine is situated below the inner barrel can be supported. An air gun which is natural from a viewpoint of design can be provided even if the retainer is situated above the magazine so that an air gun which is like a real gun can be manufactured. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]      FIG. 1  is a front view showing the inner structure of the air gun in the initial state of an embodiment of the present invention. 
           [0024]      FIG. 2  is a front view showing the inner structure of the air gun when a trigger starts to be pulled from the state of  FIG. 1 . 
           [0025]      FIG. 3  is a front view showing the inner structure of the air gun when the trigger is further pulled from the state of  FIG. 2  and a bullet enters the chamber. 
           [0026]      FIG. 4  is a front view showing the inner structure of the air gun when the trigger is further pulled from the state of  FIG. 3  and engagement between the trigger and shear is released. 
           [0027]      FIG. 5  is a front view showing the inner structure of the air gun when the inner barrel moves to the rear of the gun due to the biasing force of the main spring from the state of  FIG. 4  and a bullet enters the inner barrel. 
           [0028]      FIG. 6  is a front view showing the inner structure of the air gun at the instant when the inner barrel further moves towards the rear side of the gun from the state of  FIG. 5  due to the biasing force of the main spring, and the inner barrel contacts the hit pin. 
           [0029]      FIG. 7  is a front view showing the inner structure of the air gun when the inner barrel further moves towards the rear side of the air gun due to the biasing force of the main spring from the state shown in  FIG. 6 , pushes the valve via the hit pin, and the high-pressure gas starts entering the inner barrel from the gas chamber. 
           [0030]      FIG. 8  is a front view showing the inner structure of the air gun when a bullet is moving towards the muzzle in the inner barrel due to the gas pressure from the state shown in  FIG. 7 . 
           [0031]      FIG. 9  is a front view showing the inner structure of the air gun immediately before the inner barrel moves towards the muzzle due to the biasing force of the valve spring from the state shown in  FIG. 8 , and the trigger returns to the initial state shown in  FIG. 1 . 
           [0032]      FIG. 10  is a front view of the retainer of an air gun according to an embodiment of the present invention. 
           [0033]      FIG. 11  is a plain view of a retainer of an air gun in accordance with an embodiment of the present invention. 
           [0034]      FIG. 12  is a right side view of a retainer of an air gun according to an embodiment of the present invention. 
           [0035]      FIG. 13  is a left side view of a retainer of an air gun according to an embodiment of the present invention. 
           [0036]      FIGS. 14 through 17  are magnified views of substantial parts showing the actions of the retainer of the air gun according to an embodiment of the present invention. 
           [0037]      FIG. 18  is a cross-sectional view taken along line A of  FIG. 14 . 
           [0038]      FIG. 19  is a cross-sectional view taken along line B of  FIG. 15 . 
           [0039]      FIG. 20  is a cross-sectional view taken along line C of  FIG. 16 . 
           [0040]      FIG. 21  is a cross-sectional view taken along line D of  FIG. 17 . 
           [0041]      FIG. 22  is a front view showing the inner structure of the air gun according to the conventional technology. 
           [0042]      FIG. 23  is an explanatory drawing of substantial parts showing the actions of an air gun according to the conventional technology. 
           [0043]      FIG. 24  is an explanatory drawing of substantial parts showing the actions of an air gun according to the conventional technology. 
           [0044]      FIG. 25  is an explanation drawing of substantial parts showing the actions of an air gun according to the conventional technology. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0045]    An air gun according to an embodiment of the present invention will now be explained using  FIGS. 1 through 9  which are front views showing actions before shooting a bullet,  FIGS. 10 through 13  respectively showing the front view, plan view, left side view and right side view,  FIGS. 14 through 17  which are front magnified views of substantial parts showing the actions of the retainer of the air gun, and  FIGS. 18 and 20  which are cross-sectional views taken along line A, B, C and D of  FIGS. 14 through 17 . 
         [0046]    An air gun according to an embodiment of the present invention consists of gun main body  1 , trigger  2  which is rotatable with respect to the gun main body centering on a trigger axis  3 , magazine  16  and gas cylinder  18  contained in a grip  8 , barrel weight  9 , shear  4 , inner barrel  10 , chamber  6 , retainer  7 , hit pin  12 , valve  13  and gas chamber  15 .  18  is a gas cylinder contained in the grip  8 , which is connected to a gas chamber  15  via gas supply opening  19 . 
         [0047]    The trigger  2  is equipped with a trigger spring  20 . As shown in  FIG. 1 , the trigger  2  is biased rotatably in a clockwise direction by the trigger spring  20 . The upper end  2   a  of the trigger  2  abuts on the shear  4 . The upper end rotates towards the muzzle and presses the shear  4  by pulling the trigger  2  towards the rear side of the gun. 
         [0048]    The barrel weight  9  is fixed to the outer surface of the inner barrel  10 . The shear  4  is mounted rotatably centering on the shear rotational axis  9   a  mounted on the barrel weight  9 . The tip of the shear  4   a  is biased downwards and latched with the shear engagement part  9   b  of the barrel weight  9  by biasing the spring receiver  4   b  towards the muzzle by the shear spring  5 . 
         [0049]    The inner barrel  10  is slidably inserted into the gun main body  1 . The main spring  11  is placed on the peripheral surface of the muzzle side of the inner barrel  10 . The main spring  11  biases the inner barrel  10  towards the rear end of the gun. 
         [0050]    The chamber  6  is equipped so that the rear part of the inner barrel  10  can be inserted. The retainer  7  is equipped above the chamber  6 , and the upper end opening  160  of the magazine  16  contained in the grip  8  is opened below the chamber. The bullets W are supplied to the chamber  6  one by one from the upper end opening  160  of the magazine  16 . The upper end opening  160  of the magazine  16  is closed by the lower surface of the rear side of the inner barrel  10  when the air gun is in rest state (i.e., the state in which the trigger  2  is not pulled, refer to  FIG. 1 ). 
         [0051]    The retainer  7  is installed above the chamber  6  and the inner barrel  10 , and is placed so that it can rotate in an anteroposterior direction of the gun centering on the retainer rotational axis  70  and is biased rotatably towards the retainer spring  71  (in a clockwise direction in the front view). The retainer rotational axis  70  is hooked and fixed to the left and right side of the chamber  6  of the gun. 
         [0052]    The retainer  7  has a shape as shown in  FIGS. 10 through 13 , and has a retainer axis engagement part  72  and bullet abutment part  73 , which in this embodiment are a single-piece. The retainer axis engagement part  72  is substantially tube shaped, with the retainer rotational axis  70  placed in the chamber  6  being rotatably engaged in the tube. 
         [0053]    The bullet abutment part  73  is formed by projecting from a part of circumference of the tube of the retainer axis engagement part  72 . The rotating tip has a concave abutment surface  730 . In this embodiment, the shape of the concave abutment surface  730  of the bullet abutment part  73  seen from the axial direction of the retainer rotational axis  70  is like the rotational circular arc of the retainer. The shape seen from the axial direction and perpendicular direction of the retainer rotational axis  70  is that the center corresponding to the bullet W is concave. 
         [0054]    When the air gun is in resting state, a part of bullet abutment part  73  of the retainer  7  is engaged with the upper surface of the inner barrel  10  and rotation towards the front of the gun is restricted when the air gun is in the resting state (i.e., the state in which the trigger  2  is not pulled, refer to  FIG. 1 ). A part of the bullet abutment part of the retainer  7  abuts on the retainer engagement part  6   a  of the chamber  6 , and rotation towards the front of the gun is restricted when the trigger  2  is pulled and the inner barrel  10  moves towards the front of the gun. 
         [0055]    The hit pin  12  is made of a hollow member. It can move back and forth in the gun and is placed on the gun rear-end side of the chamber  6 . The tip on the muzzle side of the hit pin  12  can be inserted into the inner barrel  10 . The middle part has an abutment circumferential surface which abuts on the rear-end of the inner barrel  10 . The valve  13  of the hit pin is inserted into the rear side of the gun. 
         [0056]    The valve  13  consists of a circular body and has the gas vent hole  130  on the circumferential surface of the rear side. It can move back and forth in the gun with the hit pin  12 . The tip side of the valve  13  is inserted into the rear side of the hit pin  12 . The rear side of the valve  13  can be inserted into the gas chamber  15 , and is biased towards the muzzle direction by the valve spring  14  placed in the gas chamber  15 . In the resting state (the trigger  2  is not pulled), the valve  13  is biased in the direction of the muzzle by the valve spring  14  so that the opening on the side of the muzzle of the gas chamber  15  is closed by the circumferential convex part  131  at the rear-end of the gun so that the gas chamber  15  is made air-tight. 
         [0057]    The magazine  16  is detachably placed in the grip  8  of the gun main body  1 . The bullet W in the magazine  16  is biased upward by the magazine spring  17 . 
         [0058]    The action of the air gun in the embodiment of the present invention will now be described.  FIG. 2  shows a state where the trigger  2  is pulled towards the rear-end of the gun from the resting state shown in  FIG. 1 . When the trigger  2  starts to be pulled, the trigger  2  rotates around the trigger axis  3  resisting the rotational bias force of the trigger spring  20 . The trigger upper end  2   a  rotates towards the front of the gun to press the shear  4  engaged by the trigger upper end  2   a.  The inner barrel  10  also moves towards the front of the gun by the movement of the shear  4  towards the front of the gun. 
         [0059]    The inner barrel  10  moves towards the front of the gun resisting the biasing force of the main spring  11  to cause the main spring  11  to constrict. The retainer  7  rotates towards the front of the gun by the rotating biasing force of the retainer spring  71  towards the front of the gun by the movement of the inner barrel  10  towards the front of the gun. A part of the bullet abutment part  73  moves from the upper surface to the rear-end part of the inner barrel  10 . 
         [0060]      FIG. 3  shows the state where the trigger  2  is further pulled from the state shown in  FIG. 2 . When the trigger  2  is further pulled, the trigger top end part  2   a  further rotates towards the front part of the gun and further moves the inner barrel  10  towards the front of the gun via the shear  4 . In this state, a part of the bullet abutment part  73  of the retainer  7  abuts on the retainer engagement part  6   a  of the chamber  6 , and is engaged, the rotation toward the front of the gun stops, and the gun goes into the resting state. 
         [0061]    The upper opening  160  of the magazine  16  starts opening as a result of the movement of the inner barrel  10  towards the front of the gun. Finally, the bullets W are supplied into the chamber  6  from the upper opening of the magazine  16  one by one. At this time, the upper part of the bullet W stops by abutting on the concaved abutment surface  730  of the bullet abutment part  73  of the retainer  7  which is resting and abuts on the upper surface of the next bullet W 1 , and is engaged. At this moment, the center of the bullet W comes into line with the center of the void of the inner barrel  10 . 
         [0062]      FIG. 4  shows a state where the trigger  2  is further pulled from the state shown in  FIG. 3 . When the trigger  2  is further pulled, the trigger upper end part  2   a  rotates and is removed from the shear  4 , which makes a linear motion. The engagement between the shear  4  and the trigger upper end part  2   a  is released and the inner barrel  10  starts receding towards the rear-end side of the gun by the restoring biasing force of the main spring  11  which was pressed and constricted. When the inner barrel  10  recedes, the upper rear-end surface comes into collision with and presses the front side of the bullet abutment part  73  of the retainer  7 . This pressing of the inner barrel  10  against the bullet abutment part  73  causes the retainer  7  to start rotating backward, about the retainer rotational axis  70  and resisting rotating biasing force of the retainer spring  71 . At this time, the center of the bullet W is supported by the muzzle side opening part of the hit pin  12  and is aligned with the center of void of the inner barrel  10 . Thus, the bullet W is inserted into the inner barrel  10  without coming in contact with the inner barrel  10 . 
         [0063]    In  FIG. 5 , the engagement between the trigger upper end part  2   a  and the shear  4  is released. The inner barrel  10  presses the bullet abutment part  73  and rotates the retainer  7  backward while it backs away towards the rear-end of the gun due to the restoring biasing force of the main spring  11 . The abutment between the concave abutment surface  730  of the retainer  7  and the bullet W is released, the tip of the bullet abutment part  73  abuts on the upper circumferential surface of the inner barrel  10  and the rotation stops. At the same time, the bullet W enters the inner barrel  10  from the rear-end opening of the inner barrel  10 . 
         [0064]      FIG. 6  shows the state where the inner barrel  10  further continues to recede towards the rear-end of the gun due to the restoring biasing force of the mainspring  11  from the state shown in  FIG. 5  and the rear-end surface comes into contact with and presses the muzzle side end surface of the hit pin  12 . As a result, the hit pin  12  starts receding towards the rear-end side of the gun, and the connected valve  13  also recedes resisting the biasing force of the valve spring  14 . 
         [0065]      FIG. 7  shows the state where the inner barrel  10  further continues to recede from the state shown in  FIG. 6  and makes the valve  13  move towards the rear-end of the gun via the hit pin  12 . Then, a peripheral convex part  131  of the rear-end of the gun of the valve  13  is removed from the inner wall of the gas chamber  15  and the vent hole  130  enters the gas chamber  15 . Then, the air-tight state in the gas chamber  15  is broken and the high-pressure gas passes through the vent hole  130 , valve  13  and through the inside of the hit pin  12  to flow into the inner barrel  10 . 
         [0066]      FIG. 8  shows the state where the bullet W in the inner barrel  10  in the chamber  6  is discharged by the high-pressure gas that has flowed into the inner barrel  10  from the gas chamber  15 . The valve  13  receded in the gas chamber  15  advances by the restoration biasing force of the valve spring  14 . The opening on the muzzle side of the gas chamber  15  is closed by the peripheral convex part  131  of the rear-end of the gun and the gas chamber  15  is made air-tight again. Thus, the flow of the high-pressure gas into the inner barrel  10  stops. 
         [0067]      FIG. 9  shows the state where the inner barrel  10  also advances slightly towards the muzzle due to the advancement of the valve  13 . The trigger upper end part  2   a  rotates towards the rear-end of the gun and has contact with the shear  4  because the trigger  2  rotates, reversely by the rotating biasing force of the trigger spring  20  when a shooter releases their finger. From the state shown in  FIG. 9 , the trigger upper end part  2   a  further rotates towards the rear-end of the gun and is positioned at the rear side of the shear  4 . The gun moves into the resting state as shown in  FIG. 1 . 
         [0068]    The present invention will now be explained referring to  FIGS. 14 through 17  which are magnified views of substantial parts showing the actions of the retainer of the present invention. The rear-end surface of the inner barrel  10  hits against the muzzle surface of the bullet abutment part  73  of the retainer  7  when the inner barrel  10  recedes due to the restoring biasing force of the main spring  11  ( FIGS. 14 and 18 ). 
         [0069]    The bullet abutment part  73  starts rotating backward resisting the rotating biasing force of the retainer spring  71 , about the retainer rotational axis  70 , accompanying the backward movement of the inner barrel  10 . At this time, the central concave of the concave abutment surface  730  exists in an anteroposterior direction of the retainer  7 . The concave abutment surface  730  consists of a convex curve similar to the rotating arc when seen from the axial direction of the retainer rotational axis  70 . Thus, as shown in  FIG. 15 ,  FIGS. 19 through 16 , and  FIG. 20 , the retainer  7  can rotate smoothly along the spherical surface of the bullet W. 
         [0070]    As shown in  FIGS. 17 and 21 , the bullet abutment part  73  of the retainer  7  slides on the upper surface of the inner barrel  10  due to the rotating biasing towards the front direction by the retainer spring  21  when the bullet abutment part  73  of the retainer  7  is positioned at the upper surface of the peripheral surface of the inner barrel  10 . At the same time, the bullet W is supported by the tip surface of the bullet abutment  73  and hit pin  12 , and the upper surface of the next bullet W  1  is inserted into the inner barrel  10  without colliding with the inner barrel  10 . 
         [0071]    According to the embodiment of the present invention, the retainer  7  is rotated by the retainer spring  71  towards the front of the gun, but the biasing force is not made stronger and is in fact much weaker than the related art 2, and thus the friction resistance against the upper surface of the inner barrel  10  is very small. 
         [0072]    In the related art 2, the biasing force of the main spring  11  should be strong in order to cause the inner barrel  10  to retreat against the strong biasing force, because the biasing force of the retainer spring  105  is strong. The frictional force against the inner barrel  10  is very small because the retainer spring  71  of the present invention has a rotational biasing force. Therefore, the biasing force of the main spring  11  for retreating the inner barrel  10  may be weak. The force for pulling the trigger  2  to advance the inner barrel  10  is also small. Thus, this invention has an advantage of improving the operability of the air gun. 
         [0073]    The present invention can be used in air guns for competitions and amusement.