US2050538A

US2050538A - Automatic firearm

Info

Publication number: US2050538A
Application number: US530825A
Authority: US
Inventors: Frederick T Moore
Original assignee: Colts Manufacturing Co Inc
Current assignee: Colts Manufacturing Co Inc
Priority date: 1931-04-17
Filing date: 1931-04-17
Publication date: 1936-08-11
Anticipated expiration: 1953-08-11

Description

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W$ 9 i Q W\ E i d m F Aug. 11, 1936. F. "r. MOORE AUTOMATIC FIREARM Original Filed April 17, 1931 Patented Aug. 11, 1936 UNITED STATES PATENT OFFICE AUTOMATIC FIREARM Connecticut Application April 17, 1931, Serial No. 530,825 Renewed October 2, 1933 14 Claims.

The present invention is particularly applicable to automatic firearms of the type disclosed in patents to John M. Browning No. 1,293,021 dated February 4, 1919 and No. 1,628,226 dated May 10, 1927; but the invention is not necessarily so limited.

In an automatic firearm of the type described the cartridges are automatically supplied to the gun, as by means of a flexible belt, and if firing is discontinued before the cartridge supply is exhausted a live cartridge remains in the firing chamber of the barrel. If the gun has been operated continuously for a substantial period of time the barrel may be quite hot, particularly if the gun is not provided with a liquid-containing cooling mechanism. The heat of the barrel is transmitted to the cartridge in the firing chamber, with the possible result that the cartridge is exploded and there occurs a delayed and unexpected firing of the gun. Such delayed firingis obviously very dangerous.

In accordance with the present invention, the breech bolt, instead of being in its forward position at the. conclusion. of firing, is held in its rearward position, and the construction of the gun is such that the cartridge is thus maintained in a rearward position and is prevented from entering the chamber of the heated barrel. When resumption of firing is desired the breech bolt may be released and permitted to move forward in the usual way.

While my invention is particularly applicable to an automatic firearm such as described, I do not necessarily so limit myself, as some features of the invention may be found useful in firearms of other types.

In the accompanying drawing I have shown the embodiment of the invention which I now deem preferable, but it will be understood that the drawing is intended for illustrative purposes only and is not to be construed as defining or limiting the scope of the invention, the claims forming a part of this specification being relied upon for that purpose.

i. the drawing:

Fig. 1 is a combined side and longitudinal sectional view. of a firearm embodying the invention.

Fig. 2 is a view similar to Fig. 1, but showing the operative parts in different relative positions.

Fig. 3 is a fragmentary plan view of the mechanism shownrin'Fig. 1, the top plate of the gun being assumed to have been removed.

Fig. 4 is an enlarged fragmentary transverse sectional view taken along the line 4-4 of Fig. 1.

Fig. 5 is an enlarged fragmentary transverse sectional view taken along the line 5-5 of Fig. 1.

Referring to the drawing, i represents as an entirety the breech or main casing of the gun which is generally rectangular in transverse section. Projecting from the casing I at the forward end is a cylindrical jacket 2 which surrounds a barrel 3 having a firing chamber 4 at the rear end thereof. Located within the casing is a breech bolt 5 which is held in locked relationship with the barrel at the time of firing, but which is movable rearward separately from the barrel as the result of the recoil action. A buffer is provided at 6 for limiting the rearward movement of the breech bolt. Following recoil the breech bolt is returned in the forward direction by a suitable means such as a reaction spring I.

The cartridges are fed to the gun by means of a flexible belt which passes through a transverse feed channel 8 in the forward part of the casing I and the breech bolt 5 carries an extractor 9 which serves to withdraw a cartridge from the belt upon each rearward movement of the breech bolt. Fig. 2 shows a cartridge C in the position which it occupies when the breech bolt and extractor are in their rearmost positions. It will be apparent that when the breech bolt and extractor again move forward the cartridge C is pushed into the firing chamber 4.

The mechanism of the gun for effecting and controlling the movements of the breech bolt, the extractor and other parts is not shown in detail, as this mechanism does not of itself constitute any part of the invention and is, or may be, similar to thoseshown in the before-mentioned patents to John M. Browning.

The breech bolt 5 carries a firing pin [0, the rear portion of which is shown in Fig. 1. This firing pin is engaged by a vertically movable sear II, the sear being held in engagement with the firing pin by means of a spring if. A pivoted cocking lever l3 serves to move the firing nin relatively. rearward during rearward movement of the breech bolt. Mounted on the casing is a trigger bar l4 which is so located as to be adapted to engage the sear II when the breech bolt and sear are in their forward positions. I do not limit myself as concerns the exact construction of the trigger bar l4, but I prefer and have shown a trigger bar which is horizontally pivoted between its ends at IS, the forward end of the bar being positioned and shaped to engage the sear as already described. The rear end of the trigger bar I4 is positioned to be engaged by a forward extending portion of a pivoted trigger Hi. It will be observed that when the trigger i6 is pressed downward the forward extension thereof will rfiove upward, causing the trigger bar l4 to turn in the clockwise direction and thus depress the sear H and release the firing pin [0. A stop I! limits the movement of the trigger bar.

It will be understood'that when it is desired to fire a. volley, that is, a number of shots in rapid succession, the trigger I6 is depressed and kept depressed, thereby maintaining the forward end of the trigger bar l4in its lower position and in the path of the top of the sear. The trigger bar is provided with a cam surface at l4 which serves to depress the sear as the breech bolt moves forward, the parts being so proportioned that the sear releases the firing pin at exactly the proper time. When firi'ng takes place the breech bolt again moves rearward to effect the various operations which have been described, and upon the return forward movement firing is repeated. These operations are automatically repeated as long as the trigger is kept depressed and cartridges are supplied.

Mounted in the breech casing near the rear thereof is a locking member i 8 which is adapted to engage the breech bolt to hold it in its rearward position as shown in Fig. 2. This locking member or holding means is preferably a pivoted pawl having a horizontal transverse pivotal support at IS. The breech bolt 5 has a notch 20 therein into which the pawl l8 may enter to engage and hold the breech bolt. The pawl I8 is automatically moved into the notch 20 by gravity, but it ;will be understood that a spring may be added to assist this action if found necessary. It will be apparent that if the pawl I8 is allowed to act normally it will engage and hold the breech bolt whenever the breech bolt is moved to its rearward position. It will be observed that the pawl 18 is positioned entirely within the casing, and is pivoted near its forward end. The pawl extends rearward from its pivot and is therefore in compression when in engagement with the bolt. This construction gives a maximum of strength-for a given weight.

The pawl I8 is preferably relatively wide so as to have extended engagement with the breech bolt, and it is provided with a central notch 2| through which the trigger bar l4 extends. The upper edge of the rear portion of the trigger bar engages the pawl I 8, and the lower edge of the trigger bar engages a transverse lug 22 on the pawl. It will be observed that the trigger bar itself together with the trigger l6, constitute manually controllable means which serve to move the locking member in such a way as to release the breech bolt. It will be evident that movement of the trigger and of the trigger bar serves to move the pawl l8 and to thus release the breech bolt, and that this same movement serves to bring the forward end of the trigger bar into position to depress the scar and release the firing pin to cause firing.

As the result of the automatic action of the gun, firing will continue so long as the trigger I6 is pressed, it being evident that the trigger bar will continue to hold the pawl It! in its upper inoperative position. It will further be evident that upon release of the trigger the pawl l8 will engage the breech bolt upon its next rearward movement and will retain it in its rearward position as shown in Fig. 2. Thus the cartridge 0 is held out of the firing chamber 4 as already explained.

Preferably the pivotal axis at IQ for the pawl l8,

instead of being in fixed relationship to the casing. is relatively movable.' The pawlis pivotally connected to the rear portion of a horizontal rod 23, which is longitudinally movable in a housing 24 secured to the casing. A spring 25 surrounds the rod 23 and tends to hold it in its rearmost position, the spring thus constituting an element of the means for holding the breech bolt. The spring 25 serves to absorb the rebound which occurs when the breech bolt engages the bufier 6, thus eliminating the shock and vibration which would occur if pivotal connection for the pawl l8 were fixedly and rigidly mounted. The housing 24 which carriesthe rod 23 is secured in the upper right hand corner of the casing by means of rivets 26, 26, and there may also be provided a dowel washer 21 which is seated in part in a shallow cylindrical hole in the housing 24 and in part in a similar hole in the top wall of the casing.

From the foregoing description it will be understool that the pawl 18 and the parts which immediately support it are entirely additional to the firing mechanism of the gun and are entirely independent of the feeding mechanism thereof. The pawl serves the described purpose of retaining the breech bolt in its retracted position at the conclusion of firing instead of allowing it to return to its forward position. The pawl, while performing this function, does not otherwise modify the action of the gun and does not interfere with the normal functioning of the firing and feeding mechanisms. The construction is such that if for any reason it is not desired to retain the breech bolt in retracted position after firing the pawl and its associated parts can be readily removed from the gun independently of any part of the firing mechanism. This removal can be eifected by first removing the nut at the forward end of the rod 23 and then withdrawing the pawl, l8, the rod 23 and the spring 25 rearward from the casing, the rear plate being first removed to permit such withdrawal.-

What I claim is:

1. In a firearm of the class described, the combination of a main casing, a barrel, a breech bolt movable upon recoil rearward separately from the barrel, means for returning the breech bolt in the forward direction after recoil, cartridge feeding mechanism, manually controllable firing mechanism, automatically operative means additional to the firing mechanism for holding the breech bolt in its rearward position, and a device separate from the feeding mechanism and operable by the trigger of the firing mechanism for releasing the said holding means.

2.'In an automatic firearm of the class described, the combination of a main casing, a barre]. a breech bolt movable upon recoil rearward separately from the barrel, means for returning the "breech bolt in the forward direction after recoil, cartridge feeding mechanism, firing mechanism including a manually controllable element on the casing adapted when in operative positiorT to eifect firing at the conclusion of each forward movement of the breech bolt, automati- ,cally operative. means additional to the firing .ward separately from the barrel, means for returning the breech bolt in the forward direction after recoil, cartridge feeding mechanism, firing mechanism,

scribed, the combination mechanism including a manually controllable element on the casing adapted when in operative position to effect firing at the conclusion of each forward movement of the breech bolt, automatically operative means additional to the firing mechanism and independent of the feeding mechanism for retaining the breech bolt in its .rearward position, a device manually operable by the trigger of the firing mechanism for holding the bolt retaining means in an inoperative position, and means for detachably engaging the bolt holding means and permitting its complete removal independently of any part of mechanism.

4. In a firearm of the class described, the combination of a main casing, a barrel, a breech bolt movable upon recoil rearward separately from the "barrel, means for returning the breech bolt in the forward direction after recoil, cartridge feeding mechanism, manually controllable firing mechanism, and a pawl adapted to automatically engage a shoulder formed directly on the breech bolt to hold the said bolt in its rearward position, the said pawl being located entirely within the casing and being additional to the firing mechanism and independent of the feeding and a manually. operable device separate from the feeding mechanism for releasing the said pawl.

5. In an automatic firearm of the class deof a main casing, a barrel, 9, breech bolt movable upon recoil rearward separately from the barrel, means adapted to return the breech bolt in the forward direction after recoil, a firing pin and a sear therefor carried by the movable breech bolt, a looking member on the casing adapted to engage the breech bolt to hold it in its rearward position, and a manually controllable means on the casing serving to move the locking member to release the breech bolt and also serving to move the sear to release the firing pin when the bolt is in its forward .position.

6. In an automatic firearm of the class described, the combination of a main casing, a barrel, a breech bolt movable upon recoil rearward separately from the barrel, means adapted to return the breech bolt in the forward direction after recoil, a firing pin and a sear therefor carried by the movable breech bolt, a locking member. on the casing adapted to engage thebreech bolt to hold it in its rearward position, and a single manually operable member on the casing adapted to engage and move the locking member to release the breech bolt and also adapted to engage and move the sear to release the firing pin when the bolt is in its forward position.

'7. In a firearm of the class described,,the combination of a main casing, a barrel, a breech bolt movable upon recoil rearward separately from the barrel, means for returning the breech bolt in the forward direction after recoil, cartridge feeding mechanism, manually controllable firing mechanism, and a pawl pivoted near. its forward end and extending rearward from its pivot and adapted to automatically engage a shoulder formed directly on the breech bolt to hold the said bolt in its rearward position, the said pawl being located entirely within the easing and being additional to the firing mechanism and independent of the feeding mechanism, and a manually operable device separate from the feeding mechanism for releasing the said pawl.

8. In a firearm of the class described, the comthe firing the casingadapted to bination of a main casing, a barrel, a breech bolt movable upon recoil rearward separately from the barrel, means for returning the breech bolt in the forward direction after recoil, cartridge feeding mechanism, manually controllable firing mechanism, and a pawl adapted to automatically engage a shoulder formed directly on the breech bolt to hold the said bolt in its rearward position, the said pawlbeing located entirely within the casing and being additional to the firing mechanism and independent of the feeding mechanism, a resilient member within the casing associated with the pawl and adapted to permit the pawl to move to absorb the shock engagement with the bolt, and a manually operable deviceseparate from the feeding mechanism for releasing the said pawl.

9. An automatic firearm as set forth in claim 6,

wherein the manually operable memberis a lon- 10. In a firearm of the class described, the

combination of a main casing, a barrel, a breech bolt movable upon recoil rearward separately from the barrel, means for returning the breech bolt in the forward direction after recoil, cartridge feeding mechanism, manually controllable firing mechanism, for holding the breech bolt in its rearward position, the said holding means including a resilient element adapted to absorb shock, and a device manually operable by the trigger of the firing mechanism for releasing the said holding means.

11. In an automatic firearm of the class described, the combination of a main casing, a barrel, a breech bolt movable upon recoil rearward separately from the barrel, means for returning the breech bolt in the forward direction after recoil, cartridge feeding mechanism, firing mechanism including a manually controllable element on the casing adapted when in operative position to effect firing at the conclusion of each forward movement of the breech bolt, automaticallyoperative means for holding the breech bolt in its rearward position, the said means including a resilient element adapted to absorb shock, and a device manually operable by the trigger of the firing mechanism for mainautomatically operative means taining the holding means in an inoperative posibarrel, 9, breech bolt movable upon recoil rearward separately from the barrel, means adapted to return the breech bolt in the forward direction after recoil, a firing pin and a sear therefor carried by the movable breech bolt,a trigger bar on the casing adapted to engage the sear to release the firing pin when the bolt is in its forward position, a locking member adapted to engage the breech bolt to hold it in its rearward position, means for resiliently connecting the locking member with the casing, and manually controllable means on the casing for moving the locking member to release the breech bolt.

13. In an automatic firearm of the class described, the combination of a main casing, a barrel, a breech bolt separately from the. barrel, means adapted to return the breech bolt in the forward direction after recoil, a firing pin and a sear therefor carrled by the movable breech bolt, a trigger bar on movable upon recoil rearward engage the sear to release the firing pin when the bolt is in its forward position, a longitudinally extending endwise movable rod in the casing, a spring tending to move the rod rearward, a pawl pivoted to the rod and adapted to engage the breech bolt to hold it in its rearward position, and manually controllable means on the casing for moving the pawl to release the breech bolt.

14. In an automatic firearm of the class described, the combination of a main casing, a barrel, a breech bolt movable upon recoil rearward separately from the barrel, means adapted to return the breech bolt in the forward direction after recoil, a firing pin and a sear therefor car ried by the movable breech bolt, a trigger bar on the casing adapted to engage the sear to release the firing pin when the bolt is in its forward position, a longitudinally extending endwise movable rod in the casing, a spring tending to move the rod rearward, a pawl pivoted to the rod and adapted to engage the breech bolt to hold it in its rearward position, and a manually operable longitudinally extending lever horizontally pivoted between its ends, the rear part of the lever engaging the pawl to move it and release the breech bolt and the forward part of the lever engaging the sear to move it and release the firing pin.

FREDERICK T. MOORE.