Abstract:
The present invention provides a recoil reducer that reduces the recoil when the bullet is shot from the firearm and the bolt in the machine part is moved backward. By reducing the reaction force applied to the bolt when the bullet is shot, a load applied to the shooter is reduced. Furthermore, hit accuracy is improved by stabilizing the sight, the performance of the firearm itself is not decreased. The recoil when the bullet is shot is reduced by providing a member moving in an opposite direction of a recoil direction of a bolt and providing a transmission mechanism that moves the member in the opposite direction of the recoil direction of the bolt when the bolt is moved in the recoil direction by a reaction force of shooting a bullet.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
       [0001]    This patent specification is based on Japanese patent application, No. 2014-132957 filed on Jun. 27, 2014 in the Japan Patent Office, the entire contents of which are incorporated by reference herein. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention: 
         [0003]    The present invention relates to a device that weakens the impact of recoil to stabilize the sight and reduce a load applied to hands and shoulders of a shooter when a bullet is shot from a firearm (e.g., rifle) and a bolt, a barrel and the like are moved in a recoil direction. 
         [0004]    2. Description of the Related Art: 
         [0005]      FIG. 7A  shows an outer appearance of a typical rifle for hunting or sport shooting. In a general firearm, a bolt housed in a casing of a machine part, from which a bullet is shot, is moved in the recoil direction by a reaction force when gunpowder is ignited to shoot the bullet, the recoil when shooting the bullet is received by a recoil spring provided on an end portion in the recoil direction, and the bolt is returned to the original position by elasticity of the recoil spring. 
         [0006]    In principle, in the machine part shown in  FIG. 7B , bullets are loaded in a cartridge by pulling back a bolt  6  in an arrow direction in the figure using a not illustrated bolt lever. Then, when a trigger is pulled, the bolt  6  is moved forward (rightward in the figure), a firing pin  64  of the front end strikes a percussion cap located at a bottom of the bullet, and propellant in the cartridge is ignited to shoot the bullet ( FIG. 7C ). When the bullet is shot, a reaction force of the ignition is applied backward (leftward in the figure) to the bolt, the cartridge is discharged and the reaction force is reduced by a repulsion force of a recoil spring  2 , which is in contact with the rear end of the bolt, and the bolt is returned to the original position ( FIG. 7D ). In the way of returning, a notch formed at a bottom of the bolt is hooked by a stopper, which is fitted onto the trigger. Thus, the next bullet can be loaded and the next shooting can be prepared. 
         [0007]    In the technological concept disclosed in Patent Document 1, a cylindrical buffer is provided behind the bolt and inside the cylindrical buffer is made airtight. Thus, both the recoil spring and an air brake of the cylindrical buffer reduce the recoil so as to reduce a load applied to shoulders of a shooter. In the means disclosed in Patent Document 2, with respect to the reaction force applied to the bolt, which moves backward when the bullet is shot, an opposing force is generated forward, which is opposite direction of the reaction force, to reduce the recoil. In this means, the recoil is reduced by pushing the barrel itself forward as a counterweight to generate the opposing force. 
         [0008]    [Patent Document 1] Japanese unexamined patent application publication No. 2001-153594 
         [0009]    [Patent Document 2] Japanese unexamined patent application publication (Translation of PCT application) No. 2003-525421 
       BRIEF SUMMARY OF THE INVENTION 
       [0010]    However, as described above, the conventional bolt  6  basically absorbs the recoil generated when the bullet is shot by the recoil spring  2 . It cannot be avoided that the recoil spring  2  receives the reaction force when the bullet is shot. Therefore, the impact when the bullet is shot is very large. For the shooter, it is a heavy burden to bear the impact and the sight is misaligned as a result. In order to reduce the above described recoil, it is also considered that a size and a material of the recoil spring built in the machine part are changed so that repulsive elastic force is weakened. However, as a disadvantage, too much time is required for the bolt  6  to return to the original position after the bullet is shot. Thus, continuous shooting is interrupted, for example. In addition, explosion property of the propellant of the bullet is limited. 
         [0011]    On the other hand, in a technological concept disclosed in Patent Document 1, as a method of reducing the reaction force when shooting the bullet, the recoil spring  2  in contacted with a rear end of the bolt  6  and an air brake of the cylindrical buffer are simultaneously used for reducing strong impact. This is effective in terms of reducing the reaction force doubly. In this point, there is an effect of slowly transferring the recoil energy, which is directed backward (direction of the shooter). However, the movement of the return becomes slow and therefore bad influence may occur when loading the next bullet, for example. In a technological concept disclosed in Patent Document 2, as a means of directing the reaction force, which is originally directed in the recoil direction, also forward, the barrel itself is allowed to move forward to counterbalance the reaction force. However, since the barrel itself is moved forward as a counterweight, shooting force itself is decreased and therefore bad influence may occur in the performance of the gun. Namely, initial speed of the bullet may decrease. 
         [0012]    The present invention provides a recoil reducer that reduces the recoil when the bullet is shot from the firearm and the bolt in the machine part is moved backward. By reducing the reaction force applied to the bolt when the bullet is shot, a load applied to the shooter is reduced. Furthermore, hit accuracy is improved by stabilizing the sight, the performance such as the initial speed of the firearm itself is not decreased, and the operation such as the loading of the next bullet is not obstructed. 
         [0013]    In claim  1  of the present invention, a recoil reducer includes: a bolt that is installed on a first slit groove of a casing of a machine part and is slidably movable with respect to the casing; a forward moving member that is installed on a second slit groove of the casing of the machine part and is slidably movable with respect to the casing in an opposite direction of a recoil direction of the bolt; a transmission mechanism that moves the forward moving member in the opposite direction of the recoil direction of the bolt when the bolt is moved in the recoil direction by a reaction force of shooting a bullet; a first elastic body that is located between an end portion of the bolt in the recoil direction and the machine part; and a second elastic body that is located between an end portion of the forward moving member in a forward direction and the machine part. 
         [0014]    In the invention of the recoil reducer of any one of claims  1  to  5 , in order to reduce the reaction force, a recoil spring is located in contact with the end portion of the bolt in the recoil direction and a movable elastic body is located at the end portion of the forward moving member. Specifically, in the transmission mechanism, a rotating body is used for engaging the forward moving member with the bolt. More specially, a combination of a rack and pinion gear and a gear, a combination of a chain and a sprocket, or a combination of a belt and a pulley can be used. 
         [0015]    In the above, the elastic body is not limited to the spring. For example, the elastic body can be a plate spring, a rubber, and a resin having a predetermined elasticity, for example. 
         [0016]    By using the present invention, the reaction force applied to the bolt when shooting the bullet is also directed to the forward direction (shooting direction of the bullet) by the transmission mechanism. Thus, the reaction force applied to the bolt when shooting the bullet is reduced by the repulsion force of the elastic body (e.g. return spring, rubber and resin) which is in contact with the forward moving member and sliding resistance of the rotating body. Consequently, by using the recoil reducer of the present invention, the load applied to the shooter is reduced, the barrel is prevented from moving upwardly, and no problem occurs when the bolt is returned to the original position in the machine part after shooting the bullet. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1A  is a schematic cross-sectional side view showing a recoil reducer equipped with a machine part of a rifle or the like concerning an embodiment of the present invention. 
           [0018]      FIG. 1B  is a structural drawing viewed from the front of the recoil reducer equipped with the machine part of the rifle or the like concerning an embodiment of the present invention. 
           [0019]      FIG. 1C  is a perspective view showing as a whole the recoil reducer equipped with the machine part of the rifle or the like concerning an embodiment of the present invention. 
           [0020]      FIG. 2A  is a schematically enlarged view explaining an operation of the recoil reducer of the present invention in a state that a bullet is not loaded. 
           [0021]      FIG. 2B  is a schematic view explaining an operation of the recoil reducer of the present invention in a state that the bolt is pulled and the bullet is loaded. 
           [0022]      FIG. 2C  is a schematic view explaining an operation of the recoil reducer of the present invention in a state that a firing pin is striking the bullet. 
           [0023]      FIG. 2D  is a schematic view explaining an operation of the recoil reducer of the present invention in a state that the bullet is shot. 
           [0024]      FIG. 2E  is a schematic view explaining an operation of the recoil reducer of the present invention in a state that the bolt receives recoil after the bullet is shot. 
           [0025]      FIG. 3A  is a schematic cross-sectional side view showing an embodiment using a forward moving member moved by sprockets and chains in a transmission mechanism. 
           [0026]      FIG. 3B  is a schematic cross-sectional side view showing a state that the forward moving member is moved by the sprockets and the chains. 
           [0027]      FIG. 3C  is a structuring drawing viewed from the front concerning an embodiment using the forward moving member moved by the sprockets and the chains. 
           [0028]      FIG. 4A  and  FIG. 4B  show another variation of the embodiment of the recoil reducer in schematic views when one spring is used as an elastic body. 
           [0029]      FIG. 5A  and  FIG. 5B  show another variation of the embodiment of the recoil reducer. 
           [0030]      FIG. 6A  is a schematic side view of a hand gun having a slide mechanism. 
           [0031]      FIG. 6B  is a schematic front view of the hand gun having the slide mechanism. 
           [0032]      FIG. 6C  and  FIG. 6D  are schematic views of an embodiment that the present invention is applied to the hand gun. 
           [0033]      FIG. 7A  is an external view of a general rifle for hunting or sport shooting. 
           [0034]      FIG. 7B  is a drawing briefly showing an operation of the machine part of the general rifle in a state that a bolt is pulled for loading a bullet. 
           [0035]      FIG. 7C  is a drawing briefly showing an operation of the machine part of the general rifle in a state that a firing pin of the bolt is striking the bullet. 
           [0036]      FIG. 7D  is a drawing briefly showing an operation of the machine part of the general rifle in a state that recoil is applied to the bolt and a cartridge discharger is pulled after the bullet is shot. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0037]    Hereafter, the present invention will be explained based on the drawings.  FIG. 1A  shows a recoil reducer concerning an embodiment of the present invention. As shown in  FIG. 1 , a member  3  (hereafter, referred to as a forward moving member) is included in a casing  1  of a machine part so that the forward moving member  3  is slidably movable in an opposite direction with respect to a bolt  6 . The forward moving member  3  has a substantially semicylindrical shape as shown in  FIG. 1B and 1C . Movement restriction projections having a semicircular shape and projected downward are formed on both ends of the forward moving member  3 . Thus, the forward moving member  3  has a U-shape as a whole when viewed from the side. The forward moving member  3  is installed on a slit groove (second slit groove) of the casing of the machine part by a protruding slit  32  so that the forward moving member  3  is slidably movable. The forward moving member  3  is in contact with a return spring  4  (second elastic body) which is fixed to the machine part at the right end in  FIG. 1A . A rack and pinion gear  31  is formed on a bottom (lower) surface of the semicylindrical part of the forward moving member  3 . 
         [0038]    On the other hand, the bolt  6  also has a substantially semicylindrical shape. A rack and pinion gear  61  is formed on an upper surface of the bolt  6 . The bolt  6  is installed on a slit groove (first slit groove) of the casing of the machine part by a protruding slit  62  so that the bolt  6  is slidably movable. The bolt  6  is in contact with the recoil spring  2  (first elastic body) which is fixed to the machine part at a rear end (left end in  FIG. 1A ). A front end portion  63  is formed at a front end (right end in  FIG. 1A ) of the bolt  6  for housing a firing pin part. The rack and pinion gears  31  and  61  are engaged with a gear  5 , and the forward moving member  3  and the bolt  6  form a transmission mechanism in which the forward moving member  3  and the bolt  6  are movable in an opposite direction with respect to each other. A gear shaft  51  of the gear  5  is rotatably fixed to the casing of the machine part. 
         [0039]    As explained above, the present embodiment includes: the bolt  6  that is installed on a first slit groove of a casing of a machine part and is slidably movable with respect to the casing; the forward moving member  3  that is installed on a second slit groove of the casing of the machine part and is slidably movable with respect to the casing in an opposite direction of a recoil direction of the bolt; the transmission mechanism that moves the forward moving member in the opposite direction of the recoil direction of the bolt when the bolt is moved in the recoil direction by a reaction force of shooting a bullet; the first elastic body  2  that is located between an end portion of the bolt in the recoil direction and the machine part; and the second elastic body  4  that is located between an end portion of the forward moving member in a forward direction and the machine part. 
         [0040]    In the above described embodiment, the bolt  6  and the forward moving member  3  are installed on the slit grooves of the casing of the machine part and slidably movable with respect to the casing. However, other engagement mechanisms can be used to hold the bolt  6  and the forward moving member  3  slidably movable with respect to the casing. 
         [0041]    In addition, the rack and pinion gear  31  and the gear  5  are used as the transmission mechanism. The rack and pinion gear  31  and the gear  5  correspond to a rotating body engaged between the bolt  6  and the forward moving member  3 . 
         [0042]    Furthermore, in the above described embodiment, the bolt  6  and the forward moving member  3  have a substantially semicylindrical shape. The bolt  6  and the forward moving member  3  are arranged vertically so that flat surfaces of the bolt  6  and the forward moving member  3  face each other. 
         [0043]      FIG. 1C  shows a perspective view as a whole. As explained above, the forward moving member  3  and the bolt  6  have a substantially semicylindrical shape and the forward moving member  3  and the bolt  6  are slidably installed on the casing of the machine part by the protruding slits  32  and  62 . However, the above explained shape and installing method to the machine part are merely an example. The shape and the installing method can be changed according to the shape of the casing of the machine part. In addition, the gear  5  has a longitudinal shape, and the gear  5  is in contact with the rack and pinion gears at the bottom (lower) surface of the forward moving member  3  and the upper surface of the bolt  6 . In addition, a cartridge discharge opening notch  33  is formed at substantially central lower part of the forward moving member  3  for discharging the cartridge. After the bullet is shot, the cartridge is discharged diagonally upward by the notch  33  and a not illustrated discharging mechanism. 
         [0044]    The operation of the recoil reducer will be explained by using  FIGS. 2A to 2E . The recoil reducer is shown in a schematically enlarged manner As shown in  FIG. 2A , when shooting the bullet, a bullet is loaded by pulling back the bolt  6  using a not illustrated bolt lever or the like. In an automatic loading, pressure of shooting gas of the previous bullet is used to pull back the bolt  6 . When the bolt  6  is pulled back, the recoil spring  2  located at the rear end of the bolt is compressed and the gear  5  is rotated while being engaged with the rack and pinion gears  31  and  61 . At the same time, the forward moving member  3  is moved in a forward direction (rightward in the figure) and the return spring  4  is compressed ( FIG. 2B ). If a trigger is pulled in this state, a percussion cap located at a bottom of the loaded bullet is struck by a firing pin of the front end of the bolt  6  by using spring resiliency of the recoil spring  2  and the return spring  4  in an extension direction ( FIG. 2C ). Then, the bullet is shot by explosion of the gunpowder ( FIG. 2D ). 
         [0045]    In the above explained process, the bolt  6  is moved in the recoil direction (leftward in  FIGS. 2A to 2E ) by the reaction force of the explosion of the gunpowder. As a result, the recoil spring  2 , which is in contact with the bolt  6  at the rear end, is compressed and the reaction force is reduced. At the same time, the gear  5  is rotated when the bolt is moved backward. The forward moving member  3 , which is engaged with the gear  5  by the rack and pinion gears  31  and  61 , is moved forward and the return spring  4 , which is in contact with the forward moving member  3 , is compressed. Therefore, spring force pulling the forward moving member  3  is generated in a return direction (opposite direction of arrow direction in  FIG. 2E ). In other words, the reaction force received by the bolt when shooting the bullet is transferred to the forward moving member  3  and directed forward by the gear  5  and the rack and pinion gears  31  and  61 . Thus, the repulsion force of the return spring  4  functions as an opposing force of the reaction force when shooting the bullet so as to reduce the reaction force. From the above, the recoil transmitted to the shooter is reduced and the gun itself is stabilized. Note that the recoil spring  2  and the return spring  4  are so-called recoil spring. The recoil spring  2  and the return spring  4  are not limited to a spiral-shaped spring. Various methods using elastic bodies such as an air brake and a hydraulic brake can be used instead if airtightness is kept. Furthermore, the method of transferring the force is not limited to a method of using the engagement of the rack and pinion gears. For example, a roller-shaped rotating body on which an elastic body having frictional resistance is covered can be used instead if enough durability is achieved. 
         [0046]    In the above described embodiment, a rotating body, which is slid between the bolt  6  and the forward moving member  3 , is used as the transmission mechanism. 
         [0047]    In the example of  FIGS. 2A to 2E , the transmission mechanism is formed by engaging the rack and pinion gears with the gear. On the other hand, in an embodiment of  FIGS. 3A to 3C , the transmission mechanism is achieved by connecting the bolt  6  and the forward moving member  3  by using sprockets and chains. Different from the embodiment of  FIGS. 2A to 2E , the reaction force and recoil is reduced by using one elastic body, i.e., a dual-purpose spring  12  which serves both as the recoil spring  2  and the return spring  4 . 
         [0048]    As shown in  FIG. 3A , the forward moving member  3  and the bolt  6  are connected with sprockets  10  and  11 , which are relatively large and located between the front of the bolt  6  and the rear of the forward moving member  3 , by using a chain  9 . One dual-purpose spring  12  is installed between a left projection of the forward moving member  3  and a rear end of the bolt  6 . When the bullet is shot and the bolt  6  is moved backward, the chain  9  connected to the bolt  6  is rotated (clockwise in the figure). Accordingly, the forward moving member  3  connected to the chain  9  is moved in a direction opposite to the moving direction of the bolt  6  and the rear end of the dual-purpose spring  12  is compressed by the forward moving member  3 . Namely, the reaction force generated when the bullet is shot and the bolt  6  is moved backward is reduced by both the bolt  6 , which is moved backward to compress the dual-purpose spring  12  from the front, and the forward moving member  3 , which generates the forward reaction force to compress the dual-purpose spring from the rear ( FIG. 3B ).  FIG. 3C  shows a structure viewed from the right in  FIGS. 3A and 3B . Note that a belt can be used for the above described sprocket and chain if enough strength and durability are achieved. 
         [0049]    In the above described embodiment, a combination of a belt and a gear is used as the transmission mechanism. 
         [0050]      FIGS. 4A ,  4 B,  5 A and  5 B show various embodiments of the recoil reducer concerning a combination of the forward moving member  3  and the bolt  6 .  FIGS. 4A and 4B  show an embodiment that two springs corresponding to the recoil spring and the return spring are installed at left and right of the gear  5  with the gear  5  as the center. Although a method of fixing the gear  5  with the neighboring spring is not especially shown in  FIGS. 4A and 4B , fixing members can be easily attached to the gear shaft of the gear and the casing of the machine part.  FIGS. 5A and 5B  show an embodiment that the projection of the forward moving member  3  is in contact with the rear end (left end in the figure) of the recoil spring and the dual-purpose spring is used same as the example of  FIGS. 3A to 3C . 
         [0051]    Different from the embodiments shown in  FIGS. 1A to 1C  and  2 A to  2 E using two springs to reduce the reaction force, one dual-purpose spring is used in the embodiments shown in  FIGS. 3A to 3C ,  5 A and  5 B. Since the forward moving member  3  isn&#39;t moved ahead of the bolt  6  in the embodiments shown in  FIGS. 3A to 3C ,  5 A and  5 B, the notch for discharging the cartridge is not required on the forward moving member  3 . 
         [0052]    In the embodiments shown in  FIGS. 1A to 1C  and  2 A to  2 E, when enough length is available to install the recoil spring and the return spring on the machine part of the gun, spring force of the springs should be appropriately designed so as to weaken the spring force. On the other hand, in the embodiments shown in  FIGS. 3A to 3C ,  5 A and  5 B using the dual-purpose spring serving as the recoil spring and the return spring, when the length to install the spring is limited, for example, the spring having strong spring force should be used. In other words, how to determine the repulsion force of the spring is different depending on the reaction force is reduced by using one spring or two springs. 
         [0053]    In an operation of manually loading the first bullet, the repulsion force is generated in the return spring located at the side of the forward moving member when the bolt is pulled backward. Also in the dual-purpose spring, if the repulsion force is designed to be strong, difficulties occur in operation. Therefore, the spring having an appropriate repulsion force should be used considering the area of installing the spring. Furthermore, since the reaction force varies depending on a weight of the bullet and an amount of the gunpowder, an appropriate spring force should be adjusted also in such a point of view. 
         [0054]    For example, considering a structure and a size of the firearm, it can be decided that a plurality of springs is used or a single dual-purpose spring is used. 
         [0055]      FIGS. 6A to 6D  schematically show an application example applied to a slide type handgun. As shown in  FIGS. 6A and 6B , a sliding part  13  (black colored part) is built into the hand gun in a state of being structurally separated from a body frame which includes a grip. A bolt and a firing pin are installed in the sliding part  13 . The sliding part  13  forms a whole sliding mechanism covering a bullet loading part and a barrel. When the bullet is shot, the sliding mechanism is slid backward and the sliding mechanism is in contact with a recoil spring  21  installed in the body fame. By compression repulsive force of the recoil spring  21 , the reaction force generated when shooting the bullet is reduced and the sliding mechanism is returned to the original position. 
         [0056]    An embodiment shown by cross-sectional view in  FIGS. 6C and 6D  is equivalent to the recoil reducer shown in  FIGS. 5A and 5B . Namely, in this embodiment, a rack and pinion gear  31  is installed above the sliding mechanism, a thin gear  14  is installed on a side of the sliding mechanism, and a forward moving member  3  is provided to be in contact with the rear end (left end in the figure) of the dual-purpose spring  12  of the body frame. Also in this embodiment, when the bullet is shot and the sliding mechanism is slid backward (leftward in the figure), the forward moving member which is in contact with the gear  14  is accordingly moved forward (rightward in the figure). By repulsive force of dual-purpose spring  12 , the reaction force generated when shooting the bullet is reduced. Since the hand gun has properties of small size and portability, it is difficult to obtain a large area for installing the recoil reducer. Therefore, the recoil reducer is preferably used for stabilizing the sight by preventing the barrel from moving upwardly when shooting the bullet, for example. 
         [0057]    The present invention is industrially applicable because it can be valuably used for hunting or sport shooting. 
         [0058]    Note that, this invention is not limited to the above-mentioned embodiments. Although it is to those skilled in the art, the following are disclosed as the one embodiment of this invention.
       Mutually substitutable members, configurations, etc. disclosed in the embodiment can be used with their combination altered appropriately.   Although not disclosed in the embodiment, members, configurations, etc. that belong to the known technology and can be substituted with the members, the configurations, etc. disclosed in the embodiment can be appropriately substituted or are used by altering their combination.   Although not disclosed in the embodiment, members, configurations, etc. that those skilled in the art can consider as substitutions of the members, the configurations, etc. disclosed in the embodiment are substituted with the above mentioned appropriately or are used by altering its combination.