Patent Publication Number: US-8109260-B2

Title: Toy gun

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application is based on and claims the benefit of priority of Japanese Patent Application No. 2009-198006 filed on Aug. 28, 2009, the entire contents of which is incorporated herein by reference. 
     TECHNICAL FIELD 
     The present invention relates to a toy gun so configured that pressure arising from compressed gas is applied to a bullet to fire it off by a user pulling the trigger. 
     BACKGROUND 
     There are conventionally toy guns so configured that pressure arising from compressed gas is applied to a bullet to fire it off by a user pulling the trigger. (An example is the automatic toy gun described in Japanese Unexamined Patent Publication No. Hei 10 (1998)-197200.) This type of toy gun is used by toy gun enthusiasts for fun in target shooting (plinking) or the like at home. 
     The automatic toy gun described in Japanese Unexamined Patent Publication No. Hei 10 (1998)-197200 is of open bolt type. Brief description will be given to the action of a forward/backward action bolt  11  observed when bullets are fired off from this automatic toy gun. When the trigger  1  is pulled with the forward/backward action bolt  11  in a standby position close to the rear end of the gun, the following takes place: a recoil spring  27  pushes the forward/backward action bolt  11  and a hammer  21  integrally provided on the forward/backward action bolt  11  hits a opening/closing valve member  51 . As the result of hitting by the hammer  21 , a bullet BB receives gas pressure and is accelerated in the direction toward the front end of a gunbarrel  2  and fired off from the gun. Substantially immediately after the bullet BB is fired off from the gunbarrel  2 , the forward/backward action bolt  11  starts to move back in turn due to gas pressure from an accumulator  50  and the biasing force of a rebound spring  29 . 
     Many toy gun users request of a toy gun that it not only fires off bullets but also provides functions and the sense of use similar to those of real guns. In a toy gun so configured that a valve is opened and closed in conjunction with the movement of a bolt in the back and forth direction of a gunbarrel and a bullet is thereby loaded and fired off, the following is implemented: high impact is produced by the movement of the bolt and this makes it possible to obtain the sense of use close to that of a real gun. For this reason, toy guns so configured that a bolt is moved and bullets are thereby fired off are more popular than toy guns with a fixed bolt. 
     The toy gun described in Japanese Unexamined Patent Publication No. Hei 10 (1998)-197200 is so configured that the following is implemented: a bolt moves forward and hits a valve and thereby opens the valve to fire off a bullet; and after the bolt thereafter moves back, the valve is closed. As mentioned above, this toy gun provides the sense of use close to that of a real gun. In case of this toy gun, however, the hammer, the valve, and bullets are not positioned in alignment. If the hammer, the valve, and bullets exist in alignment, it must be possible to further reduce the size of a bullet firing mechanism and more efficiently apply gas pressure to bullets. Aside from the automatic toy gun described in Japanese Unexamined Patent Publication No. Hei 10 (1998)-197200, an open bolt-type toy gun in which a hammer, a valve, and bullets exist substantially in alignment is possible. This will be designated as toy gun in virtual case. 
     This toy gun in virtual case is equipped with a movable bolt. This bolt has at its rear part a space (variable volume pressure chamber) into which air or gas flows. This variable volume pressure chamber is a space into which gas flows after a bullet is fired off. Gas that flowed into this variable volume pressure chamber pushes the bolt backward by its pressure. As long as the variable volume pressure chamber is filled with gas, the gas continuously pushes the bolt backward. That is, the above bolt moves backward after a bullet is fired off. This bolt breaks away from a valve body immediately before it arrives at the backmost retreat position. This removes the airtightness in the bolt and the gas in the variable volume pressure chamber is discharged to the atmosphere. As a result, the pressure of the gas in the variable volume pressure chamber is reduced. 
     For this reason, the following takes place in the toy gun in virtual case: the time for which the bolt continuously receives pressure from gas is lengthened as the closed-end cylindrical portion forming the variable volume pressure chamber becomes longer. As a result, the recoil shock given to the user by the toy gun in virtual case is also increased. 
     However, lengthening the closed-end cylindrical portion poses another problem. As the closed-end cylindrical portion becomes longer, the distance the bolt travels until it hits the hammer after it is fit into the closed-end cylindrical portion is lengthened. As a result, the air in the closed-end cylindrical portion functions as if it were a buffer material (air cushion) and this reduces the impact by which the bolt hits the hammer. If the recoil spring is strengthened to increase the impact by which the hammer is hit to solve the above problem, a new problem would arise. The recoil shock produced when the bolt is moved backward by gas pressure is reduced. 
     SUMMARY 
     Accordingly, an object of the present invention is to produce high impact when a bullet is fired off with a toy gun so configured that a bullet is fired off by gas pressure and at the time of blowback and further simultaneously achieve smooth bullet firing and blowback actions. 
     According to the present invention, A toy gun includes a barrel extended in the back and forth direction of a gunbarrel, a valve body formed in the shape of a cylinder extended in the back and forth direction of the gunbarrel, having an air chamber to be filled with compressed gas formed therein, communicating with the rear-side end of the barrel on the front side, and having a through hole penetrating the valve body in the back and forth direction of the gunbarrel formed on the rear side, a discharge valve positioned in the valve body and so provided that the discharge valve can be displaced between a closed position where the communication between the barrel and the air chamber is shut and an open position, located in front of the closed position, where the communication between the barrel and the air chamber is opened, a discharge valve spring pushing the discharge valve backward and positioning the discharge valve in the closed position, a bolt provided so that the bolt can freely slide in the back and forth direction of the gunbarrel, including a fit receiving portion which has an opening and to which the outer circumferential surface of the valve body on the rear side is fit through the opening and an abutment portion provided on the bottom portion of the fit receiving portion opposite the opening, and displaced between a pressing position where the abutment portion is abutted against the discharge valve and the discharge valve is positioned in the open position and a retreat position, behind this pressing position, where the abutment portion is caused to break away from the discharge valve, a bolt spring pushing the bolt forward, a communicating portion provided at the bottom portion of the bolt, an opening/closing body including a slidable shank which is inserted into the communicating portion and forms an air gap between the shank and the inner circumferential surface of the communicating portion, a lid portion which is provided at the front end of the shank and has such a shape as to cover the communicating portion, and a coming-off preventing portion which is provided on the shank and prevents the opening/closing body from coming off forward, and an opening/closing body spring pushing the opening/closing body forward. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       A more complete appreciation of the present invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: 
         FIG. 1  is a left side view of a toy gun in a first embodiment; 
         FIG. 2  is a left sectional view illustrating the internal structure of a toy gun in the first embodiment; 
         FIG. 3  is a sectional view taken along line A-A of  FIG. 2 ; 
         FIG. 4  is a left side view illustrating how a discharge valve shuts the communication between a barrel and an air chamber in the first embodiment; 
         FIG. 5  is a left side view illustrating how the discharge valve opens the communication between the barrel and the air chamber in the first embodiment; 
         FIG. 6  is a left sectional view of a bolt in the first embodiment; 
         FIG. 7  is a left sectional view illustrating a modification to the bolt in the first embodiment; 
         FIG. 8  is a left sectional view illustrating the action of a bolt relative to a valve body in the first embodiment; 
         FIG. 9  is a left sectional view illustrating how a lid portion is abutted against a slide projection of a discharge valve, following  FIG. 8 ; 
         FIG. 10  is a left sectional view illustrating how the lid portion is abutted against the slide projection of the discharge valve, following  FIG. 9 ; 
         FIG. 11  is a left sectional view illustrating how a flange portion is away from packing, following  FIG. 10 ; 
         FIG. 12  is a left side view illustrating the internal structure of the toy gun with the bolt moved forward, following  FIG. 2 ; 
         FIG. 13  is a left side view illustrating the internal structure of the toy gun obtained immediately after a bullet B is fired off, following  FIG. 12 ; 
         FIG. 14  is a left side view illustrating the internal structure of the toy gun with the bolt moved backward, following  FIG. 13 ; 
         FIG. 15  is a left side view illustrating the internal structure of the toy gun with an opening/closing body moved forward, following  FIG. 14 ; 
         FIG. 16A  is a left sectional view of a bolt, a valve body, and a discharge valve, illustrating a state in which a lid portion does not close a cylindrical body in a second embodiment; 
         FIG. 16B  is a left sectional view of the bolt, valve body, and discharge valve, illustrating a state in which the lid portion closes the cylindrical body  151  in the second embodiment; 
         FIG. 17A  is a left sectional view illustrating a bolt, a valve body, and a discharge valve, illustrating a state in which a lid portion does not close a cylindrical body in a third embodiment; and 
         FIG. 17B  is a left sectional view of the bolt, valve body, and discharge valve, illustrating a state in which an abutment portion pushes a slide projection of a discharge valve in the third embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Description will be given to an embodiment with reference to  FIG. 1  to  FIG. 15 . This embodiment will be designated as first embodiment for the convenience of explanation. This embodiment is an example in which the invention is applied to a continuous firing toy gun. 
       FIG. 1  is a left side view of the toy gun  101 . The toy gun  101  in this embodiment is a continuous firing toy gun used with a compressed gas cylinder  102  attached thereto. This toy gun  101  is so configured that the pressure of compressed gas filled in the compressed gas cylinder  102  is applied to a bullet B and the bullet B is thereby fired off from a muzzle  103 . To use the toy gun  101 , a user grasps its grip  104  with his/her hand and puts his/her finger on the trigger  105  and aims the muzzle  103  at a shooting target (for example, a mark). Then the user can fire off a bullet B from the muzzle  103  by moving his/her finger to pull the trigger  105  to the rear side of the toy gun  101 . 
       FIG. 2  is a left sectional view illustrating the internal structure of the toy gun  101 . In  FIG. 2  and  FIG. 12  to  FIG. 15 , the compressed gas cylinder  102  and the grip  104  are omitted. In the following description, the side on which the muzzle  103  is positioned will be designated as the front side of the toy gun  101  and the side on which the grip  104  is positioned will be designated as the rear side of the toy gun  101 . 
     First, description will be given to each part provided in the front portion of the toy gun  101 . The toy gun  101  includes a frame  111  that forms an enclosure, a magazine  112 , a barrel  113 , and a bullet feed plate  114 . In this embodiment, the frame  111  forms part of the gunbarrel and defines the back and forth direction of the toy gun  101 . The magazine  112  and the barrel  113  are protruded from the frame  111  forward of the toy gun  101 . The magazine  112  and the barrel  113  may be not protruded from the frame  111  but be housed in the frame. 
     The magazine  112  is a cylindrical member with one end being a closed end  112   a  and is capable of housing bullets B therein. A magazine spring  112   b  is attached to the inner side face of the closed end  112   a  in the magazine  112 . At the end of the magazine spring  112   b  on the opposite side to the closed end  112   a , a magazine follower  112   c  that pushes bullets B is attached. Bullets B are guided into the magazine  112  through an open end  112   d  of the magazine  112 . Instead, an opening may be provided in the magazine  112  in an appropriate place other than the open end  112   d  and a bullet B may be guided in through this opening. The magazine  112  with bullets B housed therein is attached to the front side of the frame  111  with its open end  112   d  pointed backward of the toy gun  101 . The magazine  112  may be detachable from the frame  111  or may be fixed in the frame. 
     The barrel  113  is a cylindrical member and extended in the back and forth direction of the gunbarrel. The front end of the barrel  113  is the muzzle  103 . The inside diameter of the barrel  113  is slightly larger than the diameter of each bullet B. The barrel  113  is positioned under the magazine  112  on the front side of the frame  111 . 
     The bullet feed plate  114  is a rectangular parallelepiped member. The bullet feed plate  114  is perpendicular to the magazine  112  and is placed in the frame  111 . The bullet feed plate  114  is supported by a guide member (not shown) placed in the frame  111  and can be moved in the vertical direction. The open end  112   d  face of the magazine  112  attached to the frame  111  and the open end  103   a  face of the barrel  113  on the opposite side to the muzzle  103  are abutted against the surface of the bullet feed plate  114  facing forward. 
     The bullet feed plate  114  has a bullet retention hole  114   a  in a position opposite the open end  112   d  of the magazine  112 . This bullet retention hole  114   a  is a hole in a size sufficient to house a bullet B. The lower end face of the bullet feed plate  114  is coupled to a bullet feed plate spring  115 . The other end of the bullet feed plate spring  115  on the opposite side to the bullet feed plate  114  is coupled to the inner bottom face  111   a  of the frame  111 . The bullet feed plate spring  115  pushes the bullet feed plate  114  upward and opposes the bullet retention hole  114   a  to the open end  112   d  of the magazine  112 . 
     The bullet feed plate  114  has a slope  114   b  at its lower part. The slope  114   b  is inclined so that it ascends form the rear to the front of the toy gun  101 . The bullet feed plate  114  has a space  114   c  through which the tip portion of a bolt  121  (described later) can pass above the slope  114   b.    
     A bullet B in the magazine  112  attached to the frame  111  is pushed out by the magazine follower  112   c  due to the biasing force of the magazine spring  112   b . It is then housed in the bullet retention hole  114   a  in the bullet feed plate  114 . When the bolt  121  advances forward and pushes the bullet feed plate  114  downward, the bullet B is positioned in a position opposite the open end  103   a  of the barrel  113 . (Refer to  FIG. 12 .) When a discharge valve  123  (described later) jets out compressed gas forward in this state, the bullet B is pushed out forward. It passes through the interior of the barrel  113  and is shot forward out of the muzzle  103 . (Refer to  FIG. 13 .) 
     Description will be given to each part provided in the middle of the toy gun  101  with reference to  FIG. 2 . The toy gun  101  has, in the frame  111 , the bolt  121 , a valve body  122 , the discharge valve  123 , a bolt spring  124 , packing  122   c , and the discharge valve spring  129 . 
     The bolt  121  is a cylindrical member extended in the back and forth direction of the toy gun  101 . The bolt  121  is so provided that it can freely slide in the back and forth direction of the toy gun  101  and can reciprocate between a pressing position  121 A (Refer to  FIG. 5 ) and a retreat position  121 B (Refer to  FIG. 4 ). While it reciprocates once in the back and forth direction, the bolt  121  is abutted against and breaks away from the discharge valve  123  and thereby opens and shuts the communication between the barrel  113  and an air chamber  126  (described later). 
     The bolt  121  has an opening  121   g  open forward. The bolt  121  has at its rear part a closed end  121   d  that forms the bottom portion opposite the opening  121   g . The bolt  121  has a fit receiving portion  121   i  at its rear part. The fit receiving portion  121   i  has the opening  121   g  and the closed end  121   d  at both its ends and its side face is cylindrically covered. The outer circumferential surface of the valve body  122  on the rear side is fit into this fit receiving portion  121   i  through the opening  121   g.    
     The bolt  121  has a protruded portion  121   a  protruded upward from its upper surface. The lower part of the bolt  121  on the opening  121   g  side is extended forward. The bolt  121  has a forward slope  121   b  on the under surface of this portion extended forward. The forward slope  121   b  is inclined upward as it goes from the rear to the front. 
     One end of the bolt spring  124  is abutted against the outer surface of the closed end  121   d  of the bolt  121 . The other end of the bolt spring  124  is abutted against the inner surface  111   b  of the rear part of the frame  111 . The bolt spring  124  pushes forward the bolt  121  positioned in the retreat position  121 B. (Refer to  FIG. 4  as well.) This retreat position  121 B will be described later with reference to  FIG. 4 . When the bolt spring  124  pushes the bolt  121  forward, the bolt  121  is caused to slide forward. Then the bolt brings the forward slope  121   b  of the bolt  121  into slide contact with the slope  114   b  of the bullet feed plate  114  to push the bullet feed plate  114  downward. Though detailed description will be given later, the bolt  121  that moved forward and pushed the bullet feed plate  114  downward makes the following movement: the bolt receives the pressure of compressed gas passing through an air gap S (described later) between a through hole  122   b  and a slide projection  123   b  and moves backward. The bolt  121  makes reciprocating motion and repeats the forward movement and the backward movement as mentioned above. 
     The bolt  121  has a locking projection  121   f . The locking projection  121   f  is extended from the under surface on the closed end  121   d  side. 
     The bolt  121  has an abutment portion  121   e  on the inside surface side of the closed end  121   d . The abutment portion  121   e  is fit into a fitting hole  122   f  (described next) located at the rear end of the valve body  122 . 
     The valve body  122  is a cylindrical member extended in the back and forth direction of the gunbarrel and forms therein the air chamber  126  to be filled with compressed gas. The outside diameter of the valve body  122  is smaller than the inside diameter of the bolt  121 . The valve body  122  enters the bolt  121  through the opening  121   g  and can freely slide in the back and forth direction in the bolt  121 . In the area at the front part of the toy gun  101  in the space in the valve body  122 , a space  122   g  is ensured for the discharge valve  123  (described later) to slide forward. 
     The valve body  122  has a rear lid  122   a  at its rear end. The ring-shaped packing  122   c  is attached to the end face of the rear lid  122   a  facing forward. The rear lid  122   a  has the through hole  122   b . The through hole  122   b  penetrates the rear lid in the back and forth direction of the gunbarrel and lets the exterior of the valve body  122  and the interior of the discharge valve  123  communicate with each other. The rear part of the through hole  122   b  forms the fitting hole  122   f  large in inside diameter. The abutment portion  121   e  provided on the bolt  121  is fit into the fitting hole  122   f  from outside the valve body  122 . A slide projection  123   b  (described later) provided on the discharge valve  123  enters the through hole  122   b  from inside the valve body  122 . This slide projection  123   b  is protruded to the fitting hole  122   f  side. 
       FIG. 3  is a sectional view taken along line A-A of  FIG. 2 . The slide projection  123   b  has such a shape that it can enter the through hole  122   b  in the rear lid  122   a . When it enters the through hole  122   b , the slide projection  123   b  forms an air gap S between it and the inner circumferential surface of the through hole  122   b.    
     Description will be given with reference to  FIG. 2  again. The valve body  122  has a gas introducing portion  122   d . The gas introducing portion  122   d  is protruded downward from the under surface of the valve body  122 . The gas introducing portion  122   d  is hollow and lets the space in the valve body  122  and the space outside the frame  111  communicate with each other. The gas introducing portion  122   d  is fit into an attachment hole  111   c  formed in the inner bottom face  111   a  of the frame  111 . As a result, the tip  122   e  of the gas introducing portion  122   d  is protruded downward of the frame  111 . The compressed gas cylinder  102  (not shown in  FIG. 2 ) is attached to this tip  122   e  of the gas introducing portion  122   d . The compressed gas cylinder  102  feeds compressed gas into the valve body  122  through this gas introducing portion  122   d.    
     The discharge valve  123  is a cylindrical member and its front end face is open. The outside diameter of the discharge valve  123  is smaller than the inside diameter of the valve body  122 . This discharge valve  123  is positioned in the valve body  122  and forms the air chamber  126  between the valve body  122  and the discharge valve  123 . 
     The discharge valve  123  has a flange portion  123   a  and a slide projection  123   b  at its rear end area. The flange portion  123   a  is protruded from the outer circumferential surface of the discharge valve  123  in the radial direction. The slide projection  123   b  is protruded from the rear end face of the discharge valve  123 . 
       FIG. 4  is a left side view illustrating how the discharge valve  123  shuts the communication between the barrel  113  and the air chamber  126 . The dot meshed portions in  FIG. 4  indicate areas filled with compressed gas. The discharge valve  123  has a communicating passage  123   c . The communicating passage  123   c  is a cylindrical space inclined from the direction in which the internal space of the discharge valve  123  is extended. One end of the communicating passage  123   c  communicates with the internal space of the discharge valve  123 . An opening at the other end of the communicating passage  123   c  appears between the flange portion  123   a  and the slide projection  123   b.    
     In the front end area of the outer circumferential surface of the discharge valve  123 , an O-ring  127  and a washer  128  are installed. As illustrated in  FIG. 2 , the O-ring  127  is sandwiched between the washer  128  and the inner wall of the valve body  122 . The washer  128  is positioned next to the rear part of the O-ring  127 . One end of the discharge valve spring  129  is brought into contact with the rear surface of the washer  128 . The discharge valve spring  129  is placed so that it is wound around the discharge valve  123 . The other end of the discharge valve spring  129  is brought into contact with the flange portion  123   a . The discharge valve spring  129  pushes the washer  128  and thereby presses the O-ring  127  against the inner wall of the valve body  122 . Further, the discharge valve spring  129  pushes the flange portion  123   a  of the discharge valve  123  backward to press the flange portion  123   a  against the packing  122   c  and thereby positions the discharge valve  123  in a closed position  123 A. At this time, the air chamber  126  becomes air-tight. In this state, gas introduced from the gas introducing portion  122   d  into the air chamber  126  does not leak from the front part or rear part of the valve body  122 . 
     In  FIG. 4 , the bolt  121  is positioned in the retreat position  121 B at the rear part of the toy gun  101 . The retreat position  121 B refers to a position of the bolt  121  where the abutment portion  121   e  is caused to break away from the slide projection  123   b  of the discharge valve  123 . At this time, the discharge valve  123  is pushed backward by the discharge valve spring  129 . 
       FIG. 5  is a left side view illustrating how the discharge valve  123  opens the communication between the barrel  113  and the air chamber  126 . The arrows in  FIG. 5  indicate the movement of compressed gas. In  FIG. 5 , the bolt  121  is positioned in the pressing position  121 A at the front part of the toy gun  101 . The pressing position  121 A refers to a position of the bolt  121  where the abutment portion  121   e  is abutted against the slide projection  123   b  of the discharge valve  123  to push the discharge valve  123  forward. At this time, the discharge valve  123  is moved forward and is positioned in an open position  123 B where the communication between the discharge valve  123  and the air chamber  126  is opened. When the bolt  121  is positioned in the open position  123 B, the abutment portion  121   e  of the bolt  121  enters the fitting hole  122   f  and pushes the slide projection  123   b  forward. This causes the discharge valve  123  to slide toward the space  122   g  in the valve body  122 . As a result, the flange portion  123   a  breaks away from the packing  122   c . The compressed gas filled in the air chamber  126  flows into the internal space of the discharge valve  123  through a gap formed between the flange portion  123   a  and the packing  122   c  as indicated by arrows in  FIG. 5 . Then it is jetted forward out of the discharge valve  123  and pushes out the bullet B. 
     Further, when the flange portion  123   a  and the packing  122   c  break away from each other, the compressed gas also enters the air gap S and passes through the through hole  122   b  as indicated by arrows in  FIG. 5 . This compressed gas hits against the abutment portion  121   e  of the bolt  121  and the inner surface  111   b  (Refer to  FIG. 2 ) of the rear part of the bolt  121  and pushes the bolt  121  backward. 
     When the discharge valve  123  moves forward, the discharge valve spring  129  pushes back the discharge valve  123 . This causes the discharge valve  123  to slide backward and the flange portion  123   a  is brought into tight contact with the packing  122   c . As a result, the air chamber  126  becomes air-tight again. In the air-tight state, the air chamber  126  is filled with compressed gas supplied from the compressed gas cylinder  102 . 
     Description will be back to  FIG. 2  again. Description will be given to each part provided in the rear portion of the toy gun  101 . The toy gun  101  includes the trigger  105 , a trigger spring  131 , a bolt sear  132 , and a bolt sear spring  133 . 
     The trigger  105  is positioned in front of the grip  104  (not shown in  FIG. 2 ). The trigger  105  is supported by the frame  111  so that it can be freely rotated around a fulcrum  105   a . The trigger  105  can be freely displaced between a firing position  105 A for firing bullets and a non-firing position  105 B due to the fulcrum  105   a . (The firing position is the position of the trigger  105  indicated by an alternate long and short dash line.) (The non-firing position is the position of the trigger  105  indicated by a solid line.) The trigger  105  has an operating portion  105   d  extended downward from the fulcrum  105   a . Further, the trigger  105  has a backward extended portion  105   b  extended from the fulcrum  105   a  backward of the toy gun  101 . The backward extended portion  105   b  has a bolt sear push-up portion  105   c  protruded upward from its upper surface. 
     The trigger spring  131  is positioned behind the operating portion  105   d . The trigger spring  131  is attached to the frame  111 . The trigger spring  131  pushes the trigger  105  clockwise and pushes the trigger  105  positioned in the firing position  105 A back to the non-firing position  105 B. When an operator pulls the operating portion  105   d  backward with his/her finger, the trigger  105  is positioned in the firing position  105 A. When the operator thereafter removes his/her finger from the operating portion  105   d , the trigger  105  is displaced to the non-firing position  105 B. 
     The bolt sear  132  is provided above the bolt sear push-up portion  105   c  and under the bolt  121  in a position sandwiched between them. The bolt sear  132  is attached to the frame  111  so that it can be freely rotated around a shaft center  132   a . The bolt sear  132  includes a flat plate-like forward protruded portion  132   b  and a backward protruded portion  132   c  fanned as laterally viewed. The forward protruded portion  132   b  is protruded forward of the shaft center  132   a . The backward protruded portion  132   c  is protruded backward of the shaft center  132   a . The upper part of the backward protruded portion  132   c  is a stopper portion  132   d  for stopping the locking projection  121   f  of the bolt  121 . The bolt sear spring  133  is abutted against the under surface of the backward protruded portion  132   c . The bolt sear spring  133  rotates the bolt sear  132  counterclockwise. When the bolt sear push-up portion  105   c  pushes upward the under surface of the forward protruded portion  132   b  in this bolt sear  132 , the following takes place: the stopper portion  132   d  is displaced downward and the bolt sear  132  is positioned in a permission position  132 A (the position of the bolt sear  132  indicated by an alternate long and short dash line). The permission position  132 A refers to a position where the stopper portion breaks away from the path of the movement of the locking projection  121   f  of the bolt  121  and the reciprocating motion of the bolt  121  in the back and forth direction is permitted. Meanwhile, when the bolt sear push-up portion  105   c  breaks away from the bolt sear  132 , the following takes place: the stopper portion  132   d  is displaced upward by the bolt sear spring  133  and the bolt sear  132  is positioned in an arrest position  132 B (the position of the bolt sear  132  indicated by a solid line). The arrest position  132 B refers to a position where the stopper portion interferes with the path of the movement of the locking projection  121   f  of the bolt  121  and the reciprocating motion of the bolt  121  is arrested. 
     More detailed description will be given to the structure of the bolt  121  with reference to  FIG. 6  to  FIG. 11 .  FIG. 6  is a left sectional view of the bolt  121 . As mentioned above, the bolt  121  is a cylindrical member. While it reciprocates once in the back and forth direction of the gunbarrel, the bolt is abutted against and breaks away from the slide projection  123   b  of the discharge valve  123 . It thereby moves the discharge valve  123  forward and backward to open and shut the communication between the barrel  113  and the air chamber  126 . The bolt  121  has the fit receiving portion  121   i  and the outer circumferential surface of the valve body  122  on the rear side is fit into this fit receiving portion  121   i  in process of the bolt  121  sliding forward. 
     The closed end  121   d  that forms the bottom portion of the bolt  121  is provided with a cylindrical body  151  as a communicating portion. The cylindrical body  151  is protruded from the closed end  121   d  of the bolt  121  both in the forward direction and in the backward direction. It lets the interior of the fit receiving portion  121   i  and the exterior of the bolt  121  communicate with each other. Inside the fit receiving portion  121   i , an opening/closing body spring  152  is attached to the cylindrical body  151 . The opening/closing body spring  152  is a linear coil and is so placed that it is wound around the cylindrical body  151 . 
     The cylindrical body  151  has an opening/closing body  153  attached thereto. The opening/closing body  153  includes a shank  154 , a lid portion  155 , and a coming-off preventing portion  156 . The shank  154  is a rod-like member extended in the back and forth direction of the gunbarrel and its diameter is smaller than the inside diameter of the cylindrical body  151  and its length is larger than the length of the cylindrical body  151 . The shank  154  is inserted into the cylindrical body  151  and can freely slide in the back and forth direction of the gunbarrel. The shank  154  forms an air gap T between it and the inner circumferential surface of the cylindrical body  151 . The lid portion  155  is a disk-like member having a size sufficient to cover an end face of the cylindrical body  151 . The lid portion  155  is provided at the front end of the shank  154 . The coming-off preventing portion  156  is a member provided at the rear end of the shank  154 . When the shank  154  moves forward, the coming-off preventing portion  156  hitches on the end face of the cylindrical body  151  and prevents the opening/closing body  153  from coming off forward. In this embodiment, the shank  154  and the lid portion  155  are integrally formed. The coming-off preventing portion  156  has a hook portion (not shown) protruded to the left side (forward) in  FIG. 6 . The shank  154  is a hollow cylinder and has a hook receiving portion (not shown) formed therein, on which the hook portion of the coming-off preventing portion  156  is hooked. 
     The opening/closing body  153  and the opening/closing body spring  152  are attached to the bolt  121  as described below. First, a worker attaches the opening/closing body spring  152  around the cylindrical body  151  protruded inward of the bolt  121 . Subsequently, the worker inserts the shank  154  into the cylindrical body  151  protruded inward of the bolt  121  and positions the shank  154  and the lid portion  155  inside the bolt  121 . Next, the worker fits the hook portion (not shown) of the coming-off preventing portion  156  onto the shank  154  protruded from the end of the cylindrical body  151  outside the bolt  121 . As a result, as illustrated in  FIG. 6 , the opening/closing body spring  152  pushes the opening/closing body  153  forward and causes the lid portion  155  to break away from an end face of the cylindrical body  151 . Thus the space in the fit receiving portion  121   i  and the air gap T between the shank  154  and the inner circumferential surface of the cylindrical body  151  are connected with each other. That is, the gas flow path U illustrated in  FIG. 6  is ensured. 
     In  FIG. 6 , the coming-off preventing portion  156  is abutted against the outer end face of the cylindrical body  151 . At this time, the strength of the opening/closing body spring  152  is at such a level that the following is implemented when the pressure of compressed gas flowing in toward the fit receiving portion  121   i  is slightly larger than the atmospheric pressure: this pressure of the compressed gas pushes the surface of the coming-off preventing portion  156  facing toward the cylindrical body  151  and moves this coming-off preventing portion  156  backward. 
     As a modification, the coming-off preventing portion  156  may break away from the outer end face of the cylindrical body  151 . 
       FIG. 7  is a left sectional view illustrating a modification to the bolt  121 . As illustrated in  FIG. 7 , one in such a shape that it covers part of the outer end face of the cylindrical body  151  may be adopted as the coming-off preventing portion  156 . In the case, the following takes place when the opening/closing body spring  152  pushes the lid portion  155  forward: the space in the fit receiving portion  121   i , the air gap T between the shank  154  and the inner circumferential surface of the cylindrical body  151 , and the space outside the bolt  121  are connected with one another. That is, the flow path U′ illustrated in  FIG. 7  is ensured. 
       FIG. 8  is a left sectional view illustrating the action of the bolt  121  relative to the valve body  122 . The bolt  121  is pushed by the bolt spring  124  and linearly slides and moves forward of the toy gun  101 . At the closed end  121   d  of the bolt  121 , the cylindrical body  151  is protruded forward in a position where it is located behind the fitting hole  122   f  in the rear lid  122   a . The outside diameter of the cylindrical body  151  is smaller than the inside diameter of the fitting hole  122   f  and has such a shape that it can enter the fitting hole  122   f . The outside diameter of the opening/closing body  153  is substantially the same as the inside diameter of the fitting hole  122   f  and can enter the fitting hole  122   f . When the bolt  121  advances forward, the cylindrical body  151  and the opening/closing body spring  152  enter the fitting hole  122   f  forming part of the through hole  122   b.    
     Here, it is important that the following is implemented even though the volume of the space SP encircled by the fit receiving portion  121   i  and the rear lid  122   a  of the valve body  122  is reduced with the forward movement of the bolt  121 : the air in this space SP is discharged to outside the bolt  121  through the flow path U. As a result, the momentum of the advance of the bolt  121  pushed by the bolt spring  124  is not suppressed by the air in the fit receiving portion  121   i.    
       FIG. 9  is a left sectional view illustrating how the lid portion  155  is abutted against the slide projection  123   b  of the discharge valve  123 , following  FIG. 8 . When the bolt spring  124  further pushes the bolt  121  forward, the shank  154  and the lid portion  155  enter the fitting hole  122   f . Then the lid portion  155  is brought into contact with the slide projection  123   b  of the discharge valve  123 . That is, the cylindrical body  151  and the opening/closing body  153  function as the abutment portion  121   e.    
       FIG. 10  is a left sectional view illustrating how the lid portion  155  is abutted against the slide projection  123   b  of the discharge valve  123 , following  FIG. 9 . When the bolt spring  124  further pushes the bolt  121  forward, the lid portion  155  pushes the slide projection  123   b  forward. As a result, the discharge valve  123  becomes apt to slide forward in the valve body  122 .  FIG. 10  illustrates the state immediately before the discharge valve  123  starts to move forward and the flange portion  123   a  has not broken away from the packing  122   c  yet in this drawing. 
     When the lid portion  155  pushes the slide projection  123   b , the lid portion  155  is pushed by the slide projection  123   b . As a result, the opening/closing body  153  slides backward along the cylindrical body  151 . Consequently, the lid portion  155  closes the end face of the cylindrical body  151 . 
       FIG. 11  is a left sectional view illustrating how the flange portion  123   a  is away from the packing  122   c , following  FIG. 10 . When the lid portion  155  pushes the slide projection  123   b  of the discharge valve  123  forward, the flange portion  123   a  breaks away from the packing  122   c . As a result, the compressed gas filled in the air chamber  126  flows backward through the air gap S as indicated by arrows in  FIG. 11  and pushes the lid portion  155  and the closed end  121   d  of the bolt  121  backward. This causes the movement of the bolt  121  to shift from advance to retreat. 
     Here, it is important that such a gap as to form a flow path U is not produced between the lid portion  155  and the cylindrical body  151 . For this reason, the compressed gas that goes through the air gap S and pushes the lid portion  155  does not leak to outside the bolt  121  and produces pressure that pushes the bolt  121  backward. This makes it possible for the user of the toy gun  101  to feel high impact from the bolt  121  moving backward. 
     Description will be given to the action of each part that occurs when a user uses the toy gun  101  with reference to  FIG. 2  and  FIG. 12  to  FIG. 15 . First, description will be given with reference to  FIG. 2 . A user using the toy gun  101  performs operation of pulling the protruded portion  121   a  backward of the toy gun  101 .  FIG. 2  depicts the internal structure of the toy gun  101  with the bolt  121  positioned backward as mentioned above. When the bolt  121  is positioned backward of the toy gun  101 , the forward slope  121   b  of the bolt  121  breaks away from the slope  114   b  of the bullet feed plate  114 . Then the bullet feed plate spring  115  pushes the bullet feed plate  114  upward. As a result, the bullet retention hole  114   a  of the bullet feed plate  114  is opposed to the open end  112   d  of the magazine  112 . In this state, a bullet B in the magazine  112  is pushed out by the magazine follower  112   c  due to the pushing force of the magazine spring  112   b  and enters the bullet retention hole  114   a  in the bullet feed plate  114 . 
     In process of the bolt  121  moving backward, the locking projection  121   f  of the bolt  121  is abutted against the upper surface of the stopper portion  132   d  of the bolt sear  132  and climbs over the stopper portion  132   d . After the locking projection  121   f  climbs over the stopper portion  132   d , the bolt sear  132  is rotated counterclockwise by the elastic force of the bolt sear spring  133 . At this time, the bolt  121  becomes apt to move forward of the toy gun  101  by the elastic force of the bolt spring  124 . However, the locking projection  121   f  of the bolt  121  hitches on the stopper portion  132   d  and does not move forward any more. 
     When the user pulls the trigger  105  backward in this state, the trigger  105  rotates counterclockwise and the bolt sear push-up portion  105   c  displaces the forward protruded portion  132   b  of the bolt sear  132  upward to rotate the bolt sear  132  clockwise. This removes the engagement between the locking projection  121   f  of the bolt  121  and the stopper portion  132   d  of the bolt sear  132 . Thereafter, the bolt  121  is pushed by the bolt spring  124  and moves forward. 
       FIG. 12  is a left side view illustrating the internal structure of the toy gun  101  with the bolt  121  moved forward, following  FIG. 2 . When the bolt  121  moves forward, the under surface of the forward slope  121   b  slides so that it climbs over the slope  114   b  of the bullet feed plate  114  and pushes the bullet feed plate  114  downward. When the bullet feed plate  114  comes down, the bullet retention hole  114   a  in the bullet feed plate  114  is positioned in the position where it is opposed to the open end  103   a  of the barrel  113 . When the bolt  121  moves forward, the following takes place: the abutment portion  121   e  (the cylindrical body  151  and the opening/closing body  153 ) enters the fitting hole  122   f  in the rear lid  122   a  and pushes the slide projection  123   b  of the discharge valve  123  forward. This causes the flange portion  123   a  to break away from the packing  122   c  and the compressed gas passes forward through the space in the discharge valve  123  and flows into the bullet retention hole  114   a  in the bullet feed plate  114 . 
     As described with reference  FIG. 8  to  FIG. 11 , the following takes place when the bolt  121  moves forward: the air in the space SP encircled by the fit receiving portion  121   i  and the rear lid  122   a  is discharged to outside the bolt  121  through the flow path U. For this reason, the bolt  121  is not decelerated by the air in the space SP and rapidly presses the slide projection  123   b.    
       FIG. 13  is a left side view illustrating the internal structure of the toy gun  101  obtained immediately after a bullet B is fired off, following  FIG. 12 . The compressed gas flowing and coming forward of the valve body  122  hits the rear side face of the bullet B positioned in the bullet retention hole  114   a . Receiving the pressure of the compressed gas, the bullet B moves forward in the barrel  113  and is shot out of the muzzle  103 . When the flange portion  123   a  and the packing  122   c  break away from each other, the compressed gas pushes the bolt  121  backward. As described with reference to  FIG. 11 , the lid portion  155  has closed the cylindrical body  151  at this time. For this reason, the compressed gas pushing the bolt  121  backward does not leak from the cylindrical body  151  to the outside. 
       FIG. 14  is a left side view illustrating the internal structure of the toy gun  101  with the bolt  121  moved backward, following  FIG. 13 . When the bolt  121  is pushed by the pressure of compressed gas and moves backward, the forward slope  121   b  of the bolt  121  breaks away from the slope  114   b  of the bullet feed plate  114 . Consequently, the bullet feed plate spring  115  pushes the bullet feed plate  114  upward. As a result, the bullet retention hole  114   a  is positioned in the position where it is opposed to the open end  112   d  of the magazine  112 . A bullet B is pushed by the magazine follower  112   c  and enters the bullet retention hole  114   a.    
     The bolt  121  is pushed by compressed gas and rapidly moves backward. At this time, the opening/closing body  153  is kept positioned backward of the cylindrical body  151  and the space SP encircled by the fit receiving portion  121   i  and the rear lid  122   a  does not communicate with the outside. For this reason, the compressed gas that flowed into the space SP is all used as power for pushing the bolt  121  backward. 
       FIG. 15  is a left side view illustrating the internal structure of the toy gun  101  with the opening/closing body  153  moved forward, following  FIG. 14 . Before the bolt  121  moves backward of the toy gun  101  as far as it will go, the opening/closing body  153  is displaced forward and the flow path U is formed. This forward displacement of the opening/closing body  153  may be carried out by the elastic force of the opening/closing body spring  152 . Or, it may be carried out by the coming-off preventing portion  156  being abutted against the inner surface  111   b  of the rear part of the frame  111 . 
     While the user pulls and keeps the trigger  105  backward, the bolt sear push-up portion  105   c  keeps pushing the forward protruded portion  132   b  of the bolt sear  132  upward. For this reason, the stopper portion  132   d  of the bolt sear push-up portion  105   c  remains downward. As a result, the bolt  121  is not stopped by the bolt sear  132  and moves backward as far as it will go and is then pushed by the bolt spring  124  and starts to move forward in turn. Thus the bolt  121  receives the elastic force of the bolt spring  124  and the pressure of the compressed gas and makes reciprocating motion. While it reciprocates once, it is abutted against and breaks away from the discharge valve  123  to open and shut the communication between the barrel  113  and the air chamber  126 . In the toy gun  101 , then, the action illustrated in  FIG. 2  and  FIG. 12  to  FIG. 15  is repeated and bullets B are fired off from the muzzle  103  in rapid succession. 
     In the toy gun  101  in this embodiment, as mentioned above, the following is implemented while the bolt  121  moves forward: the flow path U for discharging the air in the fit receiving portion  121   i  to the outside is ensured; and the air in the fit receiving portion  121   i  flows along the flow path U and is discharged to the outside through the cylindrical body  151 . For this reason, impact produced when the bolt  121  pushes the discharge valve  123  is not reduced. When the bolt  121  receives the force of the compressed gas after a bullet B is fired off, the lid portion  155  has closed the cylindrical body  151  and the compressed gas that has flowed into the fit receiving portion  121   i  is not discharged to the outside. For this reason, the pressure of compressed gas pushing the bolt  121  backward is not reduced. This makes it possible to implement the following with the toy gun  101  so configured as to fire off bullets by gas pressure: the impacts produced when bullets B are fired off and at the time of blowback can be made close to those from a real gun and firing of bullets B and the action of blowback can be smoothly carried out. 
     Description will be given to another embodiment with reference to  FIG. 16A  and  FIG. 16B . This embodiment will be designated as second embodiment for the convenience of explanation. The same elements as in the first embodiment will be marked with the same reference numerals and the description thereof will be omitted. 
       FIG. 16A  is a left sectional view of the bolt  121 , valve body  122 , and discharge valve  123 , illustrating a state in which the lid portion  155  does not close the cylindrical body  151 . In this embodiment, the slide projection  123   b  provided on the discharge valve  123  is protruded to close to the rear end face of the rear lid  122   a  provided on the valve body  122 . In this embodiment, the cylindrical body  151  is not protruded inward of the fit receiving portion  121   i . That is, the end face of the cylindrical body  151  inside the fit receiving portion  121   i  is flush with the inner surface of the closed end  121   d  of the bolt  121 . 
     In this embodiment, further, the cylindrical body  151  has an opening/closing body spring receiving portion  157  at its outer end. The opening/closing body spring receiving portion  157  is protruded inward from the outer end face of the bolt  121  like a ring. One end of the opening/closing body spring  152  is abutted against the lid portion  155  and the other end is abutted against the opening/closing body spring receiving portion  157 . 
       FIG. 16B  is a left sectional view of the bolt  121 , valve body  122 , and discharge valve  123 , illustrating a state in which the lid portion  155  closes the cylindrical body  151 . In this embodiment, the lid portion  155  of the opening/closing body  153  is pushed by the slide projection  123   b  and moves backward and it is brought into contact with the closed end  121   d  of the bolt  121  and closes the cylindrical body  151 . 
     Also in the toy gun  101  in this embodiment, the air in the fit receiving portion  121   i  is discharged to the outside through the cylindrical body  151  when the bolt  121  advances. Meanwhile, when the bolt  121  receives the force of compressed gas after a bullet B is fired off, the compressed gas that has flowed into the fit receiving portion  121   i  is not discharged to the outside. For this reason, the following can be implemented in the toy gun  101  so configured as to fire off bullets by gas pressure: the impacts produced when bullets B are fired off and at the time of blowback can be made close to those from a real gun. In the toy gun  101  in this embodiment, further, the length of the cylindrical body  151  can be reduced and the shank  154  or the lid portion  155  provided in the opening/closing body  153  does not deeply enter the fitting hole  122   f . For this reason, the structure is simplified and a problem is less prone to occur in the fit receiving portion  121   i  of the bolt  121 . 
     Description will be given to another embodiment with reference to  FIG. 17A  and  FIG. 17B . This embodiment will be designated as third embodiment for the convenience of explanation. The same elements as in the first embodiment or the second embodiment will be marked with the same reference numerals and the description thereof will be omitted. 
       FIG. 17A  is a left sectional view of the bolt  121 , valve body  122 , and discharge valve  123 , illustrating a state in which the lid portion  155  does not close the cylindrical body  151 . In this embodiment, the abutment portion  121   e  is a projection protruded forward from the closed end  121   d  toward inside the fit receiving portion  121   i . The cylindrical body  151  is provided at the closed end  121   d  of the bolt  121  in a place shifted from the abutment portion  121   e . That is, in this embodiment, the cylindrical body  151  or the opening/closing body  153  does not enter the fitting hole  122   f  even when the bolt  121  moves forward and does not function as the abutment portion  121   e.    
     In this embodiment, the closed end  121   d  has a recessed portion  121   j  in its inner surface. The recessed portion  121   j  is recessed from the closed end  121   d  backward of the toy gun  101 . The lid portion  155  of the opening/closing body  153  is positioned in the recessed portion  121   j . The opening/closing body spring  152  pushes the lid portion  155  forward and positions the front surface of the lid portion  155  in a position where it is flush with the inner surface of the closed end  121   d.    
       FIG. 17B  is a left sectional view of the bolt  121 , valve body  122 , and discharge valve  123 , illustrating a state in which the abutment portion  121   e  has pushed the slide projection  123   b  of the discharge valve  123 . In this embodiment, the following takes place when the flange portion  123   a  of the discharge valve  123  and the packing  122   c  break away from each other: when the compressed gas in the air chamber  126  flows backward, the pressure in the space encircled by the rear lid  122   a  and the bolt  121  is made much higher than the atmospheric pressure by the compressed gas. When carbon dioxide gas is used for the compressed gas, for example, the pressure in the space encircled by the rear lid  122   a  and the fit receiving portion  121   i  of the bolt  121  becomes  70  atmospheres or higher. As a result, the compressed gas pushes the lid portion  155  of the cylindrical body  151  backward and the lid portion  155  is brought into contact with the bottom face of the recessed portion  121   j  and closes the cylindrical body  151 . Meanwhile, when the action of the bolt  121  is shifted to advance, the pressure in the space encircled by the rear lid  122   a  and the fit receiving portion  121   i  of the bolt  121  is at a level slightly higher than the atmospheric pressure. The atmospheric pressure in this case is much lower than the pressure arising from the compressed gas when the bolt moves backward. For this reason, the opening/closing body  153  is pushed forward by the opening/closing body spring  152  and the opening/closing body  153  does not completely close the cylindrical body  151 . 
     Also in the toy gun  101  in this embodiment, the air in the fit receiving portion  121   i  is discharged to the outside through the cylindrical body  151  when the bolt  121  advances. For this reason, ahead power is not diminished. Meanwhile, when the bolt  121  receives the force of compressed gas after a bullet B is fired off, the compressed gas that has flowed into the fit receiving portion  121   i  is not discharged to the outside. For this reason, the following can be implemented in the toy gun  101  so configured as to fire off bullets by gas pressure: the impacts produced when bullets B are fired off and at the time of blowback can be made close to those from a real gun. In the toy gun  101  in this embodiment, further, the structure of the following area is simplified: the area where the slide projection  123   b  of the discharge valve  123  and the abutment portion  121   e  of the bolt  121  collide with each other in the fit receiving portion  121   i . Therefore, a problem is less prone to occur in this area. 
     In the above description, the continuous firing toy gun  101  has been taken as examples of the first embodiment, second embodiment, and third embodiment. As other embodiments, the cylindrical body  151 , opening/closing body spring  152 , and opening/closing body  153  can also be applied to single firing toy guns and burst toy guns. 
     Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.