US2873649A - Feed devices for automatic guns supplied with ammunition in the from of a cartridge belt - Google Patents

Description

Feb. 17, 1959 B. MAILLARD FEED DEVICES FOR AUTOMATIC GUNS SUPPLIED WITH AMMUNITION I IN THE FORM OF A CARTRIDGE BELT 2 Sheets-Sheet 1 Filed Dec. 9, 1955 Feb. 17, 1959 B. MAILLARD 2,873, 4

FEED DEVICES FOR AUTOMATIC GUNS SUPPLIED WITH AMMUNITION IN THE FORM OF A CARTRIDGE BELT Filed Dec. 9, 1955 2 Sheets-Sheet 2 United States Patent 9 FEED DEVICES FOR AUTOMATIC GUNS SUP- PLIED WITH AMMUNITION IN THE FORM OF A CARTRIDGE BELT Bernard Maillard, Geneva, Switzerland, assignor to Brevets Aro-Mcaniques S. A., Geneva, Switzerland, :1 Swiss society Application December 9, 1955, Serial No. 552,133

Claims priority, application Luxembourg December 16, 1954 8 Claims. (Cl. 89-33) The present invention relates to feed devices for automatic guns supplied with ammunition in the form of a belt constituted by cartridges interconnected by flexible links, said belt being pulled toward said gun, at least once 2 For this purpose, according to the present invention,

I provide a fly-wheel coupled in rotation with at least one sprocket wheel in mesh with a portion of the belt located at a distance from the end thereof engaged by said belt feed mechanism, means being provided to cause the movement of said portion of the belt toward said gun to be stopped in response to stopping of said belt feed mechanism.

A preferred embodiment of the present invention will be hereinafter described, with reference to the accompanying drawing given merely by way of example and in which:

Fig. 1 is a diagrammatical view from the rear of an automatic gun provided with a feed device according to the present invention.

Fig. 2 shows on an enlarged scale and in side view the, I device in section on the line II-H of Fig. 1.

The automatic gun 1 diagrammatically shown on Fig. 1 is provided with a belt feed mechanism 2 pulling intermittently as long as the gun is in operation, a cartridge belt constituted by cartridges 3 interconnected by means of links 4. This belt 3-4 is pulled by the belt feed mechanism 2 either once or several times every time a shot is fired. The displacement imparted to a cartridge directly engaged by said belt feed mechanism under the effect of the pull of longest amplitude exerted by said mechanism, during every cycle of operation, is designated by d.

According to my invention, I provide, upstream of belt feed mechanism 2, a regulating unit including a fly-wheel 6 adapted to be driven in rotation, with the interposition of a torque limiting device, by a sprocket drum 7 in mesh with a portion of the cartridge belt 3-4, so that forward movement of said belt causes said flywheel to rotate.

The device includes means for causing the movement of said portion of the belt toward the gun to be stopped in response to stopping of the belt feed mechanism 2. For instance when, as shown by Fig. 1, a passage 5 is provided upstream of the belt feed mechanism for guiding the belt toward said mechanism, this passage may 7 constitute the above mentioned means. It sutfices, for

this purpose, to determine the clearance existing between the belt 34 and the inner walls of said passage 5 so that when the belt feed mechanism 2 is stopped, the. portion of the belt between said mechanism 2 and the sprocket drum 7 can only take a slightly zigzag shape between said walls, thus stopping the part of the belt engaged by sprocket drum 7 a short time after the stopping of mechanism 2.

The distance D in said passage 5, between the last cartridge engaged by belt feed mechanism 2 and the cartridge nearest thereto that is :in mesh with sprocket drum 7, is such that the total maximum possible resilient elongation of belt 3-4 between these two cartridges (that is to say over this distance D) is greater than the above specified displacement d. For instance, D is advantageously equal to 1.5 d. In the particular case where d is equal to one pitch of the belt feed mechanism 2 (that is to say is equal to the total displacement of a cartridge engaged by said belt feed mechanism during one firing cycle operation), this length D is equal to.

fifteen times this pitch.

stituted by two sprocket wheels has its shaft 8 mounted so as to be rotatable in fixed frame elements 9 rigid with passage 5.

The teeth of sprocket wheels 7 penetrate, through slots are moving along said passage.

One of the ends' of shaft 8 is coupled with' flywheel.

6 througha speed multiplying gear constituted by'an epicycloidal gear one element of which is carried the fixed frame (elements 9). I

For instance, as shown by Fig. 2, fly-wheel 6 isljour:

A torque limiting device is inserted between sleeve 17 and said fixed frame 9. Advantageously, this torque limiting device is constituted by a multiplicity of annular discs 19 and29, alternately carried by sleeve 17 (for discs 19) and a casing 21 rigid with the fixed frame of the device (for discs 20). Spring washers 22, tightly held between a part rigid with sleeve 17 and a nut 23 screwed on the end of said sleeve, apply the desired thrust on said discs 19-20 so that, for certain values of the torque exerted by sleeve 17 on casing 21, the friction between said discs 19 and 20 becomes insufiicie'nt, to prevent relative slipping between them.

A pawl 24, carried by thefixed frame-of thedevice, is: mounted to cooperate with a ratchet wheel 25 carried by,

This device works as follows. Initially, the cartridgesare located in passage 5, as shown by Fig. 1. As soon as the first shot is fired, belt feedmechanism 2 imparts a sudden pull to the first of the cartridges with which it is. engaged. The links 4 located in the portion of passage 5,

extending from mechanism 2 to sprocket wheels 7, are

stretched resiliently, and sprocket wheels 7 are started in rotation.

As the next shots are fired, the cartridge beltis pulled Patented Feb. 17, 1959- intermittently. Shaft 8, which is rigid with sprocket wheels 7, is also started in rotation and it tends to transmit this rotation, through planet-Wheels 15, to fly-wheel 6. But this fly-wheel, due to its inertia, cannot immediately follow the movement of shaft 8. The planet-wheels exert a high torque on sleeve 17 which, according to the adjustment of washers 22, will slip more or less with respect to casing 21. Due to the repeated rotational impulses transmitted to sprocket wheels 7 by cartridge belt 34, and to the frictional resistance opposed by discs 1920 to the rotation of sleeve 17, the planet-wheels gradually start the fiy-wheel 6 rotating until sleeve 17 is stationary and fly-wheel 6 is running at its highest speed, as desired. At this time, sprocket wheels 7 rotate at a nearly regular speed and exert their desired action. In other words, during the time intervals for which the cartridge engaged by the belt feed mechanism 2 is stationary, sprocket wheels 7 push the cartridges toward said belt feed mechanism and, during the time intervals where the cartridge belt is pulled by said mechanism, wheels 7 partly exert a braking action on the cartridge belt without stopping the operation of the belt feed mechanism, owing to the resiliency of links 4. Upstream of said sprocket wheels 7, the movement of the belt is practically continuous.

When the gun is stopped, fly-wheel 6 is running at its maximum speed. Since sprocket wheels 7 are stopped a short time after the stopping of the belt feed mechanism, the rotation of the fly-wheel is braked by the friction between discs 19 and 20 which slip with respect to one another, due to the fact that the torque then transmitted between the fly-wheel and the frame is higher than the predetermined value for which torque transmitting means 19-20 have been adjusted. After a relatively short time, the fly-wheel is in turn stopped.

Fly-wheel 6 can never be caused to rotate in the rearward direction owing to the cooperation of pawl 24 with ratchet-wheel 25.

In a general manner, while I have, in the above description, disclosed what I deem to be practical and ef' ficient embodiments of my invention, it should be well understood that I do not wish to be limited thereto as there might be changes made in the arrangement, disposition and form of the parts without departing from the principle of the present invention as comprehended within the scope of the accompanying claims.

What I claim is:

1. In combination, an automatic gun including a belt feed mechanism for feeding said gun with ammunition, said ammunition being in the form of a belt comprising cartridges and flexible links interconnecting said cartridges, said belt feeding mechanism intermittently pulling said belt at least once every time a shot is fired, at least one sprocket wheel located at a distance from said belt feed mechanism, said sprocket wheel being in mesh with the cartridges of said belt on their way toward said feed mechanism, mechanical means extending between said feed mechanism and said sprocket wheel arranged to cooperate with said belt to cause the forward movement of the portion of said belt in mesh with said sprocket wheel to be stopped in response to stopping of said feed mechwhen a fly-wheel, and means for coupling said fly-wheel in rotation with said sprocket wheel, said last mentioned means including a device for limiting the torque transmitted between said sprocket wheel and said fly-wheel.

2. In combination, an automatic gun including a belt feed mechanism for feeding said gun with ammunition, said ammunition being in the form of a belt comprising cartridges and flexible links interconnecting said cartridges, said belt feeding mechanism intermittently pulling said belt at least once every time a shot is fired, at least one sprocket wheel located at a distance from said belt feed mechanism, said sprocket wheel being in mesh with the cartridges of said belt on their way toward said feed mechanism, mechanical means extending between said feed mechanism and said sprocket wheel arranged to cooperate with said belt to cause the forward movement of the portion of said belt in mesh with said sprocket wheel to be stopped in response to stopping of said feed mechanism, a fly-wheel, and means for coupling said fiywheel in rotation with said sprocket wheel, said last mentioned means including a frictional transmission arranged to slip when the torque transmitted between said sprocket wheel and said fly-wheel exceeds a given value.

3. In combination, a framework, an automatic gun carried by said framework and including a belt feed mechanism for feeding said gun with ammunition, said ammunition being in the form of a belt comprising cartridges and flexible links interconnecting said cartridges, said belt feeding mechanism intermittently pull ing said belt at least once every time a shot is fired, a shaft extending at right angles to the direction of movement of said belt toward said belt feeding mechanism, said shaft being joumalled in said framework, at a distance from said belt feed mechanism, at least one sprocket wheel fixed to said shaft, said sprocket wheel being in mesh with the cartridges of said belt on their way toward said feed mechanism, a belt guiding passage rigid with said framework, extending between said feed mechanism and said sprocket wheel, arranged to cooperate with said cartridge belt to cause the forward movement of the portion of said belt in mesh with said sprocket wheel to be stopped in response to stopping of said belt feed mechanism, a fly-wheel coaxial with respect to said shaft, a plurality of spindles carried by said fly-wheel parallel to said shaft and distributed about the axis of said shaft at equal distances therefrom, a plurality of pairs of planet-wheels, the two planet-wheels of each pair being rigid and in line with each other and being rotatable about one of said spindles respectively, a sunwheel rigid with said shaft and in mesh with one planetwheel of each of said pairs of planet-wheels, a sleeve coaxially surrounding said shaft and freely rotatable with respect thereto, a second sun-wheel rigid with said sleeve and in mesh with the other planet-wheel of said pairs of planet-wheels, and means for fixing said sleeve with respect to said framework.

4. A combination according to claim 3 in which the last mentioned means are friction means arranged to permit rotation of said sleeve with respect to said framework when the torque transmitted between said sleeve and said framework exceeds a predetermined value.

5. In combination, an automatic gun including a belt feed mechanism for feeding said gun with ammunition, said ammunition being in the form of a belt comprising cartridges and flexible links interconnecting said cartridges, said belt feeding mechanism intermittently pulling sai'd belt at least once every time a shot is fired, at least one sprocket wheel located at a distance from said belt feed mechanism, said sprocket wheel being in mesh with the cartridges of said belt on their way toward said feed mechanism, mechanical means extending between said feed mechanism and said sprocket wheel arranged to cooperate with said belt to cause the forward movement of the portion of said belt in mesh with said sprocket wheel to be stopped in response to stopping of said feed mechanism, a fly-wheel, and means for coupling said fiy-wheel in rotation with said sprocket wheel, said coupling means consisting of a speed multiplying gear arranged to cause said fiy-wheel to rotate at a higher speed than said sprocket wheel.

6. In combination, an automatic gun including a belt feed mechanism for feeding said gun with ammunition, said ammunition being in the form of a belt comprising cartridges and flexible .links interconnecting said car-' tridges, said belt feeding mechanism intermittently pull-' ing said belt at least once every time a shot is fired, at.

least one sprocket wheel located at a distance from said belt "feed mechanism, said sprocket wheel being in .mesh with the cartridges of said belt on their way toward said feed mechanism, mechanical means extending between said feed mechanism and said sprocket wheel arranged to cooperate with said belt to cause the forward movement of the portion of said belt in mesh with said sprocket wheel to be stopped in response to stopping of said feed mechanism, a fly-wheel, and means for coupling said fly-wheel in rotation with said sprocket wheel, said coupling means consisting of an epicycloidal gear.

7. In combination, an automatic gun including a belt feed mechanism for feeding said gun with ammunition, said ammunition being in the form of a belt comprising cartridges and flexible links interconnecting said cartridges, said belt feeding mechanism intermittently pulling said belt at least once every time a shot is fired, at least one sprocket wheel located at a distance from said belt feed mechanism, said sprocket wheel being in mesh with the cartridges of said belt on their way toward said feed mechanism, a belt guiding passage extending between said feed mechanism and said sprocket wheel arranged to cooperate with said belt to cause the forward' 20 movement of the portion of said belt in mesh with said sprocket wheel to be stopped in response to stopping of said feed mechanism, a fly-wheel, means for coupling said fiy-wheel in rotation with said sprocket wheel, and an anti-rollback device interposed between said fiy-wheel and said passage to prevent rotation of said ily-wheel in a direction corresponding to a retrograde movement of the cartridge belt.

8. A combination according to claim 7 in which said anti-rollback device includes a pawl carried by said passage and a ratcl1et-wheel carried by said fly-wheel and cooperating with said pawl.

References Cited in the file of this patent UNITED STATES PATENTS 2,395,211 Bell et al. Feb. 19, 1946 2,456,618 Carless Dec. 21, 1948 2,561,255 White et a1. July 17, 1951 2,617,330 Pataki Nov. 11, 1952 2,629,287 Pearson Feb. 24, 1953

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