JPH07174486A - Bolt type machine gun - Google Patents

Abstract

PURPOSE:To keep a high precision of getting a target by a method wherein an operation cam for operating a lock lever is engaged with the lock lever while a cannon returns from its rear seat position to its starting position, an engagement with the lock lever is released just before the bolt part closes the and the seat returning operation of the gun is set to be stabilized. CONSTITUTION:After closing a lock claw 8, a reverse hook 17 is abutted against a reverse hook operating cam and depressed downwardly and then a stopper for the reverse hook is released from a striker 15. The striker 15 moves forward under a resilient force of a striker spring 16, projects from a front end of a bolt part 4 to repel an ammunition W and then the cannon 3 and the bolt 4 are returned back to their seats under a reaction caused by launching of the bullet. A stopping projection 9 of a lock lever passes through an operating cam 12 while the barrel 3 moves back to its seat, thereby a front part of the lock lever 7 is moved inwardly and the lock claw 8 of the lock lever is released. With such an arrangement as above, the connected state between the barrel 3 and the bolt part 4 is released. Accordingly, the seat returning operation of the barrel 3 can be stabilized and a high precision of getting a target can be maintained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pontoon cannon,
More specifically, the invention relates to a breech-bottomed machine gun in which a barrel is provided on a transition piece so as to be movable in the front-rear direction and a breech bolt is driven by internal energy.

[0002]

2. Description of the Related Art In a breech-bottomed machine gun, there has been proposed a barrel in which a barrel is provided so as to be movable in the front-rear direction, and the breech bolt is driven by utilizing internal energy without using external power. For example, there is one in which the breech hole is returned by the elastic force of the breech hole return spring, and the rear seat is moved by the rear seat movement of the barrel. This breech-bottomed machine gun has a stop lever that stops the barrel in the rear seat position where it abuts the rear seat cushioning spring, a release cam that releases the stop lever, and a closed bottom that locks the breech bolt when the barrel is closed. It is equipped with a closing device consisting of a locking lever and an actuating cam for actuating the locking lever, and operates as follows.

During firing operation, the barrel is stopped at the rear seat position by the stop lever, and the breech bolt is stopped at the rear seat position. When the stop holding of the breech is released, the breech bottom is returned by the elastic force of the breech back spring, and the stop lever is actuated by the release cam immediately after the breech is returned to release the stop holding of the barrel. As a result, the barrel starts to return due to the elastic force of the barrel return spring, and the breech bolt catches up and abuts during the return of the barrel, closing the barrel. The locking lever is actuated by the actuating cam almost simultaneously with the closing of the barrel, and the breech bolt is locked onto the barrel to maintain the closed state. Then, the barrel and the breech plate are integrally returned, and by the time the barrel reaches the retracted position, the ammunition is shot and the bullet is fired. The barrel is seated backwards by the reaction force from the firing of a bullet, but the rocking lever is opened by the actuating cam until the seating position is reached, and the locking of the breech bolt and the barrel is released. Almost at the same time, the rear seat movement of the barrel is transmitted to the breech bolt via the acceleration lever, and the breech bolt is separated from the barrel to release the closing and to be seated back.

[0004]

The conventional breech type machine gun described above can have a compact structure by driving the breech bolt by utilizing the rear seat movement of the barrel.
Since the rock lever is provided on the breech bolt, the weight of the breech bolt is increasing. As a result, the breech bolt cannot be driven at high speed, and it is difficult to increase the firing speed. Further, since the stop lever is released immediately after the breech bottom starts to be returned to the seat, the breech hole catches up with the barrel of the turret being seated and closes, and the closed position tends to become unstable. When the closed position becomes unstable, the resting energy of the breech that acts on the barrel changes and the resting movement of the barrel becomes unstable. As a result, even if the bullet is shot at a certain position, the firing position of the bullet becomes unstable, and it is difficult to maintain high accuracy of hit.

The present invention has been made in order to solve the above-mentioned conventional problems, and its object is to reduce the weight of the breech bolt to increase the firing speed and to stabilize the rearward movement of the barrel and increase the movement. An object of the present invention is to provide a breech-bottomed cannon that can maintain accuracy.

[0006]

In order to solve the above problems, the present invention reduces the weight of the play bottom by providing a lock lever for locking the play bottom with the barrel. Also, by providing an operating cam that operates the lock lever so that the lock lever engages while the barrel is returning from the rear seat position, and the engagement with the lock lever is released immediately before the breech block closes the barrel, I try to stabilize the sitting motion.

That is, according to the present invention, the rear barrel of the barrel is provided so as to be movable in the front-rear direction on the transition piece, and has the barrel that is restored by the barrel-restoring spring, and the breech that is restored by the breech-hole restoring spring. A free-bottom type machine cannon that closes the barrel by means of a breech in the seat, wherein a projection for holding the closure provided on the lateral side of the breech and a pivoting device that is swingable around an axis orthogonal to the axis of the barrel on the rear outside It has a locking claw that is supported and elastically urged outward by a closing spring, and has a locking claw that projects inward on the rear side and projects outward on the front side. A lock lever having a stop projection formed therein and an actuating cam projecting inwardly from the rear barrel near the return position of the barrel, the actuating cam returning the barrel from the rear seat position. At this time, the stop projection of the lock lever engages, and It is formed so that when the lock claw is brought into contact with the rear end surface of the bar and the lock claw is opened, the stop projection of the lock lever passes, and after the stop projection of the lock lever passes, it makes sliding contact with the outer surface of the lock lever. I am trying.

The breech-bottomed machine gun of the present invention has a firing pin that is movable forward and backward in the breech and is elastically biased forward, and a firing pin that intersects the firing pin and is vertically movable and is resiliently biased upward. And a hook that has a stopper that engages the firing pin and holds it in the standby position when it is above, and is swingably provided around an axis orthogonal to the firing pin to return the firing pin from the firing position to the standby position. The firing pin lever, a reverse hook operating cam provided on the transition piece to move the reverse hook downward after the locking claw of the lock lever engages with the projection for holding the closing of the free bottom, and the reverse bottom is seated at the rear seat position. The tail cylinder lever may be provided on the tail cylinder so as to engage with the firing pin lever immediately before.

[0009]

When the firing operation is performed, the barrel is stopped in the middle of the returning seat because the stop projection of the rock lever is engaged with the operation cam, and the breech is stopped at the rear seat position. When the stop holding of the play bottom is released, the play bottom is returned by the play bottom return spring,
It abuts the rear end surface of the lock lever and moves the rear side outward so that the lock claw is released. When the lock claw is opened, the breech bolt comes into contact with the barrel and closes, the stop projection of the lock lever disengages from the actuating cam, and the barrel starts to move back by the barrel return spring. When the barrel is returned, the stop projection of the lock lever passes through the actuating cam, the front side of the lock lever is moved outward by the closing spring, and the lock claw engages with the projection for closing and closing the breech bolt. That is, the locking lever locks the breech bolt on the barrel to maintain the closed state. The barrel and the breech plate are returned to each other in a state of being integrally connected by a rock lever, and the firing pin is activated until the barrel reaches the retracted position, and the ammunition is shot to fire the bullet.

The reaction force from the firing of the bullet acts on the barrel,
When this reaction force becomes larger than the resting energy of the barrel and breech, the barrel and breech start rear seating. The lock lever is moved inward on the front side by the stop projection thereof coming into contact with the actuating cam. That is, the rear side is moved outward, and the locking claw is disengaged from the closing holding projection of the breech bolt. At this time, the residual pressure gas in the barrel acts on the breech, and the blowback force due to this residual pressure accelerates the breech to leave the barrel, releasing the closure of the barrel. On the other hand, the barrel continues to be in the rear seat, and after reaching the rear seat position, it is replaced by the barrel return spring. At that time, since the stop projection of the lock lever has been moved outward by the closing spring after passing through the actuating cam, it is engaged with the actuating cam while the barrel is being restored, thereby stopping the barrel.
After that, the same process is repeated, and the barrel is closed and released at almost the stop position of the barrel. Since the position at which the barrel is closed is almost constant, the resting seat energy of the breech is always applied to the barrel in a constant state.

The firing pin is held at the standby position by the inverted hook during firing operation. The breech bolt is replaced and the barrel is closed, and after the lock lever locks the barrel, the reverse hook is moved downward by the reverse hook actuating cam, and the stop hook of the reverse hook comes off the firing pin. As a result, the firing pin moves forward by elastic force, projects from the front end of the breech bolt, reaches the firing position, and fires the ammunition. On the other hand, the firing pin lever engages with the tail cylinder lever immediately before the breech bolt reaches the rear seat position, and is swung with the rear seat of the breech bolt, and the firing pin is returned from the firing position to the standby position. When the firing pin returns to the standby position, the inverted hook moves upward, and the stopper engages with and holds the firing pin.

[0012]

Embodiments of the present invention will be described with reference to the drawings. 1, 2 and 3, the breech-bottomed cannon 1 has a tail tube 2 firmly attached to a shooting base (not shown), and a barrel 3 and a breech bolt 4 are movable in the tail tube 2 in the front-rear direction. It is provided. The barrel 3 is seated rearward by a reaction force generated by the firing of the ammunition W, but is replaced by a barrel return spring 5 provided between the barrel 3 and the transition piece 2. A medicine chamber 6 for accommodating ammunition W is formed inside the rear portion of the barrel 3, and a pair of lock levers 7 for locking the breech bolt 4 when the barrel 3 is closed are provided outside the rear portion. Each of the lock levers 7 has a lock claw 8 formed on the rear side thereof so as to project inward, and has a stop projection 9 formed on the front side thereof so as to project outward. The intermediate portion is pivotally supported by a rock lever shaft 10 orthogonal to the axis of the barrel 3. A closing spring 11 is provided on the front side of each lock lever 7 so as to elastically bias outward, and the locking pawl 8 is held so as to be always closed. The rear end surface of each of the lock levers 7 is formed in a tapered shape, and when the breech bolt 4 is seated back and abuts, the rear side moves outward, and the lock claws 8 are opened.
The actuating cam 12 provided at the above is also operable.

The actuating cam 12 is provided so as to project to the rear of the barrel 3 toward the returning position, and when the barrel 3 is returned from the rear seat position, the front ends of the stop projections 9 of the respective rock levers come into contact with each other. Formed to engage. As a result, the barrel 3 is stopped against the elastic force of the barrel retracting spring 5 while it is being retracted. When the breech bolt 4 is seated back and abuts on each lock lever 7, and the lock claw 8 is opened,
Each stop projection 9 is formed so as to be separated from the actuating cam 12. As a result, the barrel 3 starts to return from the stop position by the elastic force of the barrel return spring 5, and the lock levers 7
The stop projection 9 of FIG.
Also, after each stop projection 9 has passed, each lock lever 7
Is formed so as to be in sliding contact with the outer surface of the. As a result, after each lock lever shaft 10 passes through the operation cam 12, the lock claws 8 of each lock lever are held so as not to be opened.

The breech plate 4 is adapted to be restored by a breech plate return spring 13 provided between the breech plate 4 and the transition piece 2. Playground 4
Has a tapered side surface, and when the breech bolt 4 is seated back and comes into contact with the rear end surface of each lock lever 7, the rear side of each lock lever 7 is moved outward and the lock claw 8 is opened. It is supposed to be. Further, the front portion is formed so as to project laterally, and serves as a closing holding projection 14 with which the locking claw 8 of each locking lever engages when the barrel 3 is closed.

On the play bottom 4, a firing pin 15 for firing the ammunition W is provided so as to be movable in the front-rear direction. A firing pin spring 16 that elastically biases forward is provided at the rear of the firing pin 15, an inverted hook 17 that holds the firing pin 15 in the standby position, and a firing pin lever 1 that returns the firing pin 15 from the firing position to the standby position in the middle.
8 are provided. As shown in FIGS. 4 and 5, the reverse hook 17 is provided movably in the up-and-down direction so as to intersect with the firing pin 15, and is elastically biased upward by the reverse hook spring 20.
As shown in FIG. 4, the stopper 19 is formed so as to engage with the firing pin 15 when it is above, and not engage with the firing pin 15 when it is below as shown in FIG. It is designed to move downwards. The reverse hook actuating cam 21 is provided on the transition piece 2 as shown in FIG. 2, and the breech bolt 4 is returned to close the barrel 3, and the locking claw 8 of the rock lever engages with the closing retaining projection 14 of the breech bolt. After the mating, the inverted hook 17 is formed so as to come into contact and move downward.

As shown in FIGS. 6 and 7, the firing pin lever 18 is pivotally supported by a firing pin lever shaft 22 so as to be swingable in the front-rear direction, and is elastically biased clockwise by a firing pin lever spring 23. The tail barrel lever 24 provided on the barrel 2 swings counterclockwise to return the firing pin 15 to the standby position. The tail cylinder lever 24 is pivotally supported by a tail cylinder lever shaft 25 so as to be swingable in the front-rear direction in front of the rear seat position of the playground 4, and is elastically biased counterclockwise by a tail cylinder lever spring 26. As a result, the breech bolt 4 is engaged with the firing pin lever 18 during the rear seating,
The firing pin lever 18 rotates counterclockwise, but when the breech bolt 4 returns from the rear seat position, it comes into contact with the firing pin lever 18 and rotates clockwise, so that the firing pin lever 18 does not rotate. An extraction cylinder (not shown) for holding the ammunition W is provided at the front part of the breech bolt 4, the ammunition W is loaded into the barrel chamber 6 when the breech bolt 4 is retracted, and the ammunition W is emptied by the rear seat of the breech bolt 4. It is designed to pull out the medicine W. Further, on the front end side of the transition piece 2, a barrel-replacement buffer spring 2 for cushioning a shock caused by the rearward movement of the barrel 2 is provided.
7 is provided, and at the rear end side of the transition piece 2, a free-bottom rear seat cushioning spring 28 that cushions the impact of the rear seat of the flat bottom 4 is provided.

The present embodiment is constructed as described above, and its operation will be described below with reference to FIGS.
At the time of firing operation, as shown in FIG. 8, the front end of the projection 9 for stopping the lock lever abuts and engages with the operating cam 12, and the barrel 3 resists the elastic force of the barrel return spring 5 and moves back. It is stopped at a stop position on the way. The play bottom 4 is stopped against the elastic force of the play bottom return spring 13 by a play bottom stop member (not shown), and holds an ammunition W by a drawing cylinder (not shown). When the breech bolt stop member (not shown) is released, the breech bolt 4 is restored by the breech bolt recoil spring 13, and as shown in FIG. Immediately before the loading is completed, the play bottom 4 contacts the rear end surface of the lock lever 7, and the rear side of the lock lever 7 is moved outward to open the lock claw 8 as shown in FIG. Immediately after the lock claw 8 is opened, the loading of the ammunition W is completed and the breech bolt 4 is moved to the barrel 3
Abut and close.

On the other hand, when the lock claw 8 is opened, the front side of the lock lever 7 is moved inward, the stop projection 9 is disengaged from the actuating cam 12, and the barrel 3 is returned by the barrel return spring 5. . The lock lever 7 has a stop projection 9
When is passed through the operating cam 12, the front side is moved outward by the closing spring 11 to close the locking pawl 8. As a result, the locking claw 8 engages with the closing-holding projection 14 of the breech, and locks the breech 4 on the barrel 3 to hold the barrel 3 closed. Then, the barrel and the breech plate are integrally returned, but the outer surface of each lock lever is in sliding contact with the operating cam.
As shown in FIG. 5, when the rock lever shaft 10 is returned beyond the actuating cam, the rear portion of each rock lever is held so as not to move outward. After the locking claw 8 is closed, the reverse hook 17 comes into contact with the reverse hook operating cam 21 and is pushed down, and the stopper 19 of the reverse hook comes off the firing pin 15. The firing pin 15 moves forward by the elastic force of the firing pin spring 16 and
Projects from the front end of and shoots ammunition W. A bullet is fired by the bombardment of the ammunition W, and the barrel 3 and the breech bolt 4 are seated rearward by the reaction force generated by the firing of the bullet.

While the barrel 3 is seated rearward, the locking lever stop projection 9 passes through the actuating cam 12 so that the front side of the lock lever 7 is moved inward and the lock claw 8 of the lock lever 7 is opened. As a result, FIG.
As shown in FIG. 7, the lock claw 8 is disengaged from the closing holding projection 14 of the breech bolt, and the connection between the barrel 3 and the breech bolt 4 is released. Playground 4
The residual pressure of the barrel 3 acts on the barrel, and the blowback force due to this residual pressure causes the breech bolt 4 to move away from the barrel 3 to release the closed state, and is accelerated to be seated in the rear seat position. The lock lever 7 is closed by the closing spring 11 after the stop projection 9 thereof has passed through the actuating cam 12, but the breech bolt 4 has already been seated rearward and separated from the barrel 3, so that the breech bolt 4 is locked as shown in FIG. It is closed without locking. On the other hand, barrel 3
Is moved to the rear seat position and then moved forward by the barrel return spring 5, but since the lock lever 7 is in the closed state, the stop projection 9 has the actuating cam 12 as shown in FIG.
And is stopped at the stop position. In addition, empty medicine today W
Occupies the rear seat together with the breech hole 4, but is discharged from the breech hole by a discharging means (not shown) in the middle of the rear seat. Further, the next ammunition W is supplied to the play bottom 4 by the ammunition supply means (not shown) while the play bottom 4 is stopped at the rear seat position.

By the way, the firing pin 15 is in the firing position after firing the ammunition W, but is returned to the standby position while the breech bolt 4 is seated rearward. That is, when in the firing position, the firing pin 15 is in contact with the lower side of the firing pin lever 18, and the firing pin lever 1 is in contact immediately before the breech bolt 4 reaches the rear seat position.
The upper side of 8 engages with the transition piece lever 24. Then, the firing pin lever 18 is rotated counterclockwise with the rear seat of the play bottom 4,
The lower side of the firing pin lever 18 moves rearward to retract the firing pin 15. When the firing pin 15 reaches the standby position, the upper end of the stop hook 19 of the inverted hook is disengaged from the firing pin 15, and the reverse hook 17 is moved upward by the reverse hook spring 20. At the same time, the firing pin lever 18 is disengaged from the tail cylinder lever 24, and the firing pin lever spring 2
It is rotated clockwise by 3 and the lower side moves forward and the firing pin 15
Get away from. The firing pin 15 is elastically biased forward by a firing pin spring 16 and moves upwards to a stopper 19 of an inverted hook.
And is held at the standby position.

The breech-bottomed cannon 1 of this embodiment repeats the firing cycle as described above. The relationship between the strokes of the barrel 3 and the breech bolt 4 in the firing cycle is as shown in FIG. For example, at the time of closing, the breech bolt 4 is returned from the breechhole rear seat position and immediately before the barrel 3 is closed, the turret 3 starts returning from the barrel stop position. It will close in position. As a result, the resting energy of the breech bolt 4 acts on the barrel 3 effectively and in a constant state, so that the backward movement of the barrel 3 is stabilized. Further, when the reaction force of the firing becomes larger than the resting energy of the barrel 3 and the breech block 4, the barrel 3 and the breech block 4 start rear seating, but the resting energy of the breech block 4 acting on the barrel 3 is constant. Therefore, the barrel 3 will start rearward seating at a certain position behind the barrel return position. The rear seat starting position of the barrel 3 is also a bullet firing position. Therefore, the bullet is fired from a fixed position, and can be fired with high accuracy.

When the lock is released, the barrel 3 and the breech bolt 4 are seated rearward, the stop projection 9 of the lock lever abuts the actuating cam 12, and the lock of the breech bolt 4 is released when the locking claw 8 is opened. It Immediately after the lock is released, the breech bolt 4 is accelerated by the blowback force due to the residual pressure in the barrel 3, is separated from the barrel 3, and the closure is released. That is, the barrel-closed release position is the position of the barrel 3 at the time when the locking projection 9 of the lock lever contacts the actuating cam 12, and is set at a fixed position. Therefore, by setting the lock release time so that the residual pressure in the barrel 3 is in a safe and high pressure state, the blowback force due to the residual pressure can be effectively applied to the breech bolt 4, and the breech bolt 4 can thus be operated. Can be seated at high speed. The breech bolt 4 is seated back to the breech bolt rear seat position by the blowback force and stopped for a predetermined time. Barrel 3
Is the rear seat due to the reaction force of the firing, and the rear seat position is the position where the rear seat energy of the barrel 3 becomes equal to the elastic force of the barrel rear seat spring 5, and after reaching the rear seat position, the barrel rear seat spring 5 It returns to the stop position by the elastic force of.

[0023]

According to the present invention, the rock lever provided on the barrel is actuated by the actuating cam provided on the transition piece to lock the breech bolt on the barrel, so that the breech bolt can be moved to a much larger extent than before. The weight can be reduced. In the middle of the rear seat of the barrel, the breech bolt is locked to the turret by the rock lever, and when the rock lever unlocks the breech bolt, the blowback force due to the residual pressure in the barrel acts on the breech bolt. I will use my power to make it sit back. At that time, the unlocking time of the breech bolt with the lock lever is the time when the breech bolt is almost seated at the rear stop position of the barrel, and the residual pressure in the barrel is safe and high pressure. You can In addition, since the breech bolt abuts and closes immediately after the barrel starts returning from the stop position, the breech bolt is locked to the barrel by the rock lever immediately after closing,
The resting seat energy of the breech can be effectively and stably applied to the barrel. As a result, the rear seat energy of the barrel due to the reaction force of the firing can be reduced, and the rear seat stroke of the barrel can be shortened, which allows the stroke of the breech bolt to be set short. As described above, the breech bolt can be driven at a high speed and the firing speed can be increased because the breech bolt is made lighter, the blowback force is effectively applied to the breech bolt, and the stroke of the breech bolt can be set shorter. Has become possible.

As described above, since the resting energy of the breech can be effectively and stably applied to the barrel,
The return movement of the barrel is stable, and the firing position of the bullet is constant, which makes it possible to maintain high accuracy. In addition, since the rear seat energy of the barrel is reduced by the rear seat energy of the barrel and the breech, it is possible to reduce the impact force on the transition piece acting by the rear seat of the barrel.

Immediately after the barrel is closed, the rock lever locks the breech hole on the barrel, but since the outer surface of the rock lever is in sliding contact with the actuating cam, the rock lever is not opened even when the ammunition is shot and the breech hole is locked reliably. be able to. Also, when the breech bolt returns, the firing pin lever comes into contact with the tail cylinder but does not engage, and the firing pin is held in the standby position by the reverse hook, and is not released until the reverse hook comes into contact with the reverse hook operating cam. It is possible to reliably prevent the firing of ammunition by the firing pin. Therefore, the firing cycle can be performed safely.

[Brief description of drawings]

1 is an explanatory view of an embodiment of the present invention and is a cross-sectional view taken along the line AA of FIG.

FIG. 2 is a sectional view taken along line BB of FIG.

FIG. 3 is an enlarged view taken along line CC of FIG. 2, showing a part of the cross section.

FIG. 4 is an enlarged cross-sectional view taken along the line EE of FIG. 1, showing an operating state of the inverted hook.

5 is a cross-sectional view of a portion corresponding to FIG. 4, showing a non-operating state of the inverted hook.

6 is a cross-sectional view taken along the line D-D in FIG. 3, showing the relationship between the firing pin lever and the transition piece during the return of the breech bolt.

7 is a cross-sectional view of a portion corresponding to FIG. 6, showing the relationship between the firing pin lever and the transition piece when the breech bolt starts returning from the rear seat position.

FIG. 8 is an explanatory view of the operation of the embodiment of the present invention, showing a loading start state of ammunition.

FIG. 9 also shows a state immediately before closing the barrel.

FIG. 10 likewise shows the barrel closed and firing conditions.

FIG. 11 also shows a state immediately after the barrel is released from closure.

FIG. 12 is a view showing a state in which the barrel starts to return from the rear seat position and the breech bolt is in the rear seat.

FIG. 13 shows the relationship between the barrel and stroke of the breech bolt, which also correspond to the firing cycle.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Free-bottom machine cannon 2 Rear barrel 3 Gun barrel 4 Free-bottom 5 Gun barrel resting spring 7 Rock lever 8 Lock claw 9 Stop projection 10 Rock lever shaft 11 Closing spring 12 Actuating cam 13 Swing bottom resting spring 14 Closure holding projection 15 Shooting needle 16 Strike needle spring 17 Reverse Hook 18 Strike Bar Lever 19 Stopper Stopper 21 Reverse Hook Actuating Cam 24 Tail Cylinder L W Ammunition or Empty Medicine

Claims (2)

[Claims] 1. A barrel (3) which is provided on a transition piece (2) so as to be movable in the front-rear direction and which is restored by a barrel-restoring spring (5).
And the play bottom (4) that is replaced by the play bottom return spring (13)
And a closure-holding projection (1) provided on the side of the breech (4) in a breech-type machine gun (1) having a turret (4) for closing the barrel (3) while the barrel (3) is resting. 14),
The barrel (3) is pivotally supported on the outside of the rear of the barrel (3) so as to be swingable about an axis orthogonal to the axis of the barrel (3), and a closing spring (1
By 1), the front side is elastically biased outward, and the rear side has a locking claw (8) formed so as to project inward,
A lock lever (7) having a stop projection (9) formed on the front side to project outward, and a lock lever (7) projecting inward on the rear cylinder (2) rearward of the barrel (3) near the seating position. An operating cam (12) provided with an operating cam (12)
When the barrel (3) is returned from the rear seat position, the stop projection (9) of the lock lever is engaged, and the breech bolt (4) in the rear seat comes into contact with the rear end surface of the lock lever (7) so that the lock claw ( When the lock lever (8) is opened, the lock lever stop projection (9) passes through, and after the lock lever stop projection (9) passes, the lock lever (7) is formed so as to be in sliding contact with the outer surface of the lock lever (7). Characteristic pontoon cannon. 2. A firing pin (15) which is movable forward and backward and is elastically biased forwardly provided on the play bottom (4), and a firing pin (1).
5) An inverted hook (1) having a stopper (19) that is movable in the up-down direction and intersects with 5) and is elastically biased upward and that engages the firing pin (15) and holds it in the standby position when it is above.
7) and a firing pin lever (18) which is swingably provided around an axis orthogonal to the firing pin (15) and which returns the firing pin (15) from the firing position to the standby position, and the locking claw (8) of the locking lever. Of the rear hook is provided with a reverse hook actuating cam (21) provided on the transition piece (2) so as to move the reverse hook (17) downward after engaging with the closure holding projection (14) of the rear seat. 2. The cannon type cannon according to claim 1, further comprising: a tail cylinder lever (24) provided on the tail cylinder (2) so as to be engaged with the firing pin lever (18) immediately before being seated in the position.