JPH06159991A - Bolt-driving mechanism - Google Patents

Abstract

PURPOSE:To obtain a compact and strong structure wherein a bolt can be driven at high speed stably in a long period of time. CONSTITUTION:A bolt 4 is guidably supported in a tail cylinder 3 movably to a barrel 2 and is composed so as to be reciprocally moved between a retreated position drawn with a solid line and an advanced position drawn with an alternate long and two short dash line by the title mechanism 5. In the mechanism 5, a first rack 6 is provided on the undersurface of the bolt 4 along in the advanced and retreated direction thereof, a second rack 7 is provided on the bottom face of the tail cylinder 3 being opposed to the first rack 6, and a pinion 8 is provided between the racks 6, 7 by engaging with them and is connected to a crank 10 through a connecting rod 9. When the crank 10 is rotatively driven in the direction of an arrow mark, the pinion 8 is reciprocally moved on the second rack 7 while rotating and the bolt 4 is reciprocally moved over a distance of double the stroke of the pinion 8, i.e., at double the speed of the pinion 8. In this case, at the retreated and advanced positions, a crank pin 10a relatively slides by a distance M in the axial direction of the connecting rod 9 because of a slot 9a on the connecting rod 9 and thus the bolt 4 is allowed to stop for fixed time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a breech bottom type machine gun, and more particularly to a breech bolt drive mechanism for moving the breech bolt forward and backward with respect to the barrel by external power.

[0002]

2. Description of the Related Art In a breech-bottomed machine gun, a turret is guided and supported by a tail cylinder so as to be able to advance and retreat with respect to the barrel, and when the firing operation is performed, the breech is advanced to close the barrel and shoot ammunition. It is generally known in the past.

By the way, regarding the above-mentioned machine gun, it is desired to improve the firing performance, and since the firing speed of the ammunition depends on the advance / retreat speed of the breech bolt, the cam drum mechanism, the chain mechanism, the toggle mechanism, etc. Various proposals have been made to move the breech bolt back and forth by a drive mechanism that utilizes external power.

[0004]

However, the above-mentioned conventional breech bolt drive mechanism has problems that the structure is complicated, it is difficult to make it compact, it is difficult to secure sufficient durability, and it is difficult to operate the breech bolt at high speed. For example, regarding the cam drum mechanism, it is necessary to set the length of the cam drum to be equal to or greater than the movement stroke of the breech, and to temporarily stop the breech in the forward movement position and the backward movement position in order to securely perform the barrel barrel closing operation and the bullet sending operation. Therefore, the shape of the cam becomes complicated,
It is difficult to make a compact structure. Further, since the shape of the cam portion is complicated, the cam portion is easily worn by high speed operation, and it is difficult to endure long-term use. With regard to the chain mechanism, it is necessary to stretch the chain in a rectangular shape in a plan view in a range that is equal to or greater than the movement stroke of the playground and dispose the forward and backward engaging claws, which makes it difficult to have a compact structure. It is difficult to operate the breech bolt on the mechanism at a high speed, and a high load acts on the chain, so that the chain is easily worn and cannot be used for a long period of time. With regard to the toggle mechanism, it is necessary to set the radius of the toggle to be at least half the movement stroke of the playground, which makes it difficult to make the drive source large and compact in structure. It is difficult to operate the breech bolt at high speed on the mechanism, and a large amount of power is required.

The present invention has been made in view of the above conventional situation, and an object thereof is to provide a breech bolt drive mechanism having a compact and robust structure capable of stably operating the breech bolt at a high speed for a long period of time. .

[0006]

In order to solve the above-mentioned problems, in the present invention, a pinion is provided by meshing between a pair of racks provided opposite to the breech bolt and the transition piece, and the pinion is connected to the crank by a rod. By rotating the crank, the breech bolt is moved back and forth with respect to the barrel. In addition, by connecting at least one of the connecting portions of the stove and the crank or the pinion to the crank or the pinion so that the hob can be displaced relative to the axial direction, the breech bolt is moved to the forward and backward positions during rotation of the crank. It is supposed to stop temporarily.

That is, in the breech bolt drive mechanism of the present invention, the breech bolt that closes the barrel and shoots ammunition is guided and supported by the tail barrel so that it can be moved back and forth with respect to the barrel, and a pair of racks are attached to the breech bolt and the tail barrel in the forward and backward direction of the breech bolt. Along with the pinion between the racks, the crank driven to rotate is provided in the transition piece, and the pinion and the crank are connected by a stove to connect the stove to the crank or the pinion. At least one of the parts is connected to the crank or the pinion so that the hob can be displaced in the axial direction relatively.

[0008]

Embodiments of the present invention will be described with reference to the drawings. Figure 1
An open-bottom cannon 1 shown in FIG. 3 has a tail barrel 3 at the rear of the barrel 2.
2 are integrally extended, and a pair of guide grooves 3a are formed above the inside of the transition piece 3 as shown in FIG. 2, and a play bottom 4 is attached to these guides 3a. The breech bolt 4 is guided and supported so as to be movable back and forth with respect to the barrel 2, and is reciprocally moved by a breech bolt drive mechanism 5 between a retracted position shown by a solid line in FIG. 1 and an advanced position shown by a two-dot chain line. The distance between the retracted position and the advanced position of the breech bolt 4 is set to be longer than the length of the ammunition W so that the munition W can be mounted on the breech bolt 4 in the retracted position.

The breech bolt drive mechanism 5 is provided with a first rack 6 on the lower surface of the breech bolt 4 along its advancing / retreating direction, and a second rack 7 on the bottom surface of the transition piece 3 so as to face the first rack 6 and each rack. A pinion 8 is provided between 6 and 7 in mesh with each other. The pinion 8 has a pinion pin 8a protruding from both sides thereof.
Is connected to the crank 10 by rotatably pin-connecting one end side of the connecting rod 9 and by pin-connecting the other end side of the connecting rod 9 to a crank pin 10a, which will be described later. Has become.
The first rack 6 moves as the pinion 8 moves back and forth, but since the pinion 8 moves forward and backward while rotating on the second rack 7, in other words, the first rack 6 is moved to move the play bottom 4 to the movement stroke of the pinion 8. Move it back and forth with a double stroke.

In the crank 10, a pair of parallel crank arms 10b are integrally connected by a crank pin 10a, and a crankshaft 10c is provided at the base of each crank arm 10b so as to project outward, and each crankshaft 10c. Is pivotally supported on the rear portion of the transition piece 3, and a drive source (not shown) such as a motor is connected to a gear 11 fixed to one of the crankshafts 10c so as to be rotationally driven in the arrow direction. Each crankshaft 10c is provided in a plane parallel to the advancing / retreating direction of the breech bolt 4 passing through each pinion pin 8a, and the breech bolt 4 is in the retracted position in the state shown in FIG. 1 and in the forward position in the half-rotated state, It may be displaced above or below the in-plane.

The connecting portion between the connecting rod 9 and the crank 10 is provided with an elongated hole 9a extending in the axial direction of the connecting rod 9,
A crank pin 10a is attached and coupled to the elongated hole 9a. This elongated hole 9a is formed to be M longer than the diameter of the crank pin 10a, and while the crank 10 rotates by an angle α from the state shown by the solid line in FIG. 4 to reach the state shown by the two-dot chain, and FIG. The other end of the connecting rod 9 does not move while the state shown by the solid line is rotated by an angle α to reach the state shown by the two-dot chain. As a result, the pinion 8
The forward / backward movement is stopped and the play bottom 4 is stopped for a predetermined time at the retracted position and the advanced position. The angle α is
When the crank 10 rotates, the crank pin 10a slides in the oblong hole 9a, and the rotation angle of the crank 10 is within a range in which the connecting rod 9 does not move. By changing it, the stop time of the playground 4 can be adjusted. The connecting portion between the connecting rod 9 and the pinion 8 may be the same. Further, the radius of the crank 10 is such that the moving stroke of the play bottom 4 is twice the moving stroke of the pinion 8, and the moving stroke of the pinion 8 is twice the radius of the crank 10.
Since the length is obtained by subtracting the difference M from the diameter of a,
Is set to a length obtained by adding a half of the difference M to a quarter of the movement stroke of the.

The present embodiment is constructed as described above, and its operation will be described below. A drive source (not shown) is operated to rotationally drive the crank 10 in the arrow direction from the state shown by the solid line in FIG. The rotation of the crank 10 advances the connecting rod 9 to move the pinion 8 forward to the barrel 2 side. The pinion 8 advances while rotating on the second rack 7, and advances the first rack 6 or the playground 4 in other words. By rotating the crank 10 a half turn, the pinion 8 advances from the position shown by the solid line in FIG.
To the forward position. After that, the crank 10 further rotates and returns to the original position, whereby the pinion 8 is retracted and the play bottom 4 is returned to the retracted position. When the breech bolt 4 starts to move from the retracted position, the crank pin 10a slides a relatively long distance M in the slot 9a of the connecting rod while the crank 10 rotates by an angle α as shown in FIG. It rotates around the pin 8a. As a result, the pinion 8 does not move forward, and the play bottom 4 is stopped at the retracted position for a predetermined time. Therefore, new ammunition W can be mounted on the breech bolt 4 while the breech bolt 4 is stopped. On the other hand, when the play bottom 4 starts to move from the forward position, the crank pin 10a slides in the slot 9a of the stove relatively for a distance M as shown in FIG. Similarly, the play bottom 4 is stopped at the forward position for a predetermined time. Therefore, the barrel 2 can be reliably closed by the breech bolt 4 at least until after the ammunition W has been shot and before the firing is completed.

[0013]

According to the present invention, since the breech bolt is driven by the crank, the rod, the pinion and the rack, it is more durable and robust than the conventional one even when the breech bolt is operated at a high speed. It became possible to have a different structure. Since the pinion is provided by meshing with the pair of racks, the movement stroke of the pinion can be set to one half of the movement stroke of the playground and the radius of the crank can be set to about one quarter. It became possible to make the structure much more compact than that.

Further, since the breech bolt moves forward and backward with a movement stroke twice that of the pinion and the crank has a small diameter as described above, the breech bolt can be driven at high speed. In addition, since at least one of the connecting parts of the crank and the crank or the pinion is relatively displaceable in the axial direction, the breech bolt is stopped at the retracted position and the advanced position for a predetermined time while the crank is rotating. It is possible to reliably perform the bullet sending operation and the closing operation of the barrel. Therefore, it became possible to improve the high-speed firing performance of the machine gun far more than before.

[Brief description of drawings]

FIG. 1 is a conceptual vertical cross-sectional view of an embodiment.

FIG. 2 is a sectional view taken along the line AA of FIG.

3 is a cross-sectional view taken along the line BB of FIG.

FIG. 4 is an operation explanatory view of the embodiment and shows a state where the breech bolt is started to move forward from the retracted position.

FIG. 5 is an operation explanatory view of the embodiment and shows a state in which the breech bolt starts to move backward from the forward movement position.

[Explanation of symbols]

 2 Gun barrel 3 Tail tube 4 Playground 5 Playground drive mechanism 6 1st rack 7 2nd rack 8 Pinion 9 Comb rod 9a Oval slot 10c crank pin 10a Crank pin W Ammunition

Claims (1)

[Claims] 1. A breech bolt that closes the barrel and shoots ammunition is guided and supported by a tail barrel so that it can be moved back and forth with respect to the barrel, and a pair of racks are provided on the breech bolt and the tail barrel so as to face each other along the forward and backward direction of the breech bolt. A pinion is meshed between the racks, a crank that is driven to rotate is provided in the transition piece, and the pinion and the crank are connected by a stove.At least one of the connecting portion between the stove and the crank or the pinion is the crank or the crank. A playground drive mechanism characterized in that a connecting rod is connected to a pinion so as to be relatively displaceable in the axial direction thereof.