US2112660A - Automatic gun - Google Patents

Description

March 29, 1938 I F. HUDSON AUTOMATIC GUN 7 Sheets-Sheef 1 Filed June 26, 1929 m m- N 3 mm V, cm NR L L y m a N 6H0: an

March 29, 1938. R. F. HUDSON AUTOMATIC GUN Filed June 26, 1929 7 Sheets-Sheet Z Haber/ F Hudson March 29, 1938. I R. F. HUDSON 2,112,660

I AUTOMATIC GUN Filed June 26, 1929 '7 Sheets-Sheet 4 Rober/ F Hudson March 29, 1938.

Filed June 26, 1929 '7 Sheets-Sheet 5 O) 2 LL gnmbtoz Baber/ F Hudson M aflo'zucq mm 0 I1 a s 3 a a III I III,

"a VII/I IIIIIIIIIIA March 29, 19

SON

AUTOMATIC GUN Filed June 26, 1928 7 Sheets-Sheet 6 m J H M F a 1w a b# 0E buLa chu R. F. HUDSON AUTOMATIC GUN Marizh 29, 1938.

Filed June 26, 1929 '7 Sheets-Sheet 7 gmwnfo'o Roberf F Hudson Patented Mar. 29, 1938 The present gun is a gas set, mechanically op= erated, automatic gun, the power for operation being obtained by passing a portion of the pow= der gases into a gas cylinder for the purpose of compressing a main spring in a forward direction, the energy stored in the main spring being used to serve the poses of unlocking, driving the bolt and attached parts of the mechanism to the rear, and for compressing the bolt spring. This gun, similar to any automatic gun, must be retracted by hand in order to load the first cartridge into the chamber. After the first cartridge has been loaded, the trigger released, and the cartridge fired, the automatic action starts. The bolt spring, which has been compressed during the rearward movement, returns the bolt and attached mechanism forwardly, provided the trigger is pulled .to prevent the retracting catches from holdin'g the mechanism to the rear. During the rearward movement the cartridge guide and electors are held in the housing by the bolt until the bolt clears'them and allows the ejectors to be forced out of their housings by the ejector springs, so that the ejectors strike the fired cartridge case above the center line, which causes the fired case to be driven from the face of the bolt and out of the receiver.

When the cartridge is fired, a portion of the powder gases are permitted to enter the gas cylinder and drive the piston forwardly, which compresses the main spring, the surplus energy from the powder gases in the gas cylinder being transmitted to the buffer by a positive link which connects the gas piston and the bufling element at the forward end of the main spring housing. The gas used from the barrel is tapped at a point of maximum pressure, maximum temperature, and where the velocity is still increasing.

It will be found from the art of using gas power for operation, either direct or indirect, that two basic and distinctly different methods of operating are available. First, if advantage is taken of the maximum energy available from a portion of the powder gases, it must be taken at a point where the ordinate of thepowder curve is a maximum, and it must be used with a powder that will retain this maximum value of the ordinate through a considerable portion of the curve. This means that a progressive burning powder is necessary to obtain the maximum advantage to be gained when the gases are to be used at a point of maximum pressure, maximum temperature and one at which the velocity is still increasing.

The other distinct method or using powder gases for operation or the mechanism, or for counteracting the base pressure, or recoil, must use theonly remaining source, i. e., the velocity of the powder gases must be taken advantage of, which naturally indicates that this can only be accomplished at or near the muzzle of the gun. At this point, the ordinate of the powder curve is a minimum, which shows that the energy available is spent at the sacrifice of an increase in velocity. This being the case, apparently advantage must be taken of the maximum velocity to further counteract the base pressure or recoil. This may be accomplished by providing a socalled muzzle brake, which may consist of baffies, deflection plates, or slots, or any other means of checking the velocity of the powder gases to utilize the energy available from the gas, at or near a point of maximum velocity. The powder curve ordinate being a minimum, shows that the energy available, due to temperature and pressure, cannot be used at this point. The total energy available from the powder gases, their period of application, the time of the application of base pressure, or recoil, has been thoroughly analyzed.

The present automatic gun has been designed to specifically utilize the total energy available, by coordinating the time of application as near as physically possible to coincide with the period of application of the base pressure, and advantage is taken of the position of the maximum ordinate of the powder curve by taking off the operating power immediately after the maximum ordinate has been reached. This also gives the maximum period of application of the greatest energy available over as long a distance of bullet travel in bore as is possible. The application of the maximum energy available is dissipated in terms of stored operating energy, the excess is absorbed in a forward direction by a buffer means. The bullet is still in the barrel during this period of application, due to the application of the energy to the gas piston immediately after the maximum ordinate of the powder curve has been reached. The maximum ordinate, or a mean maximum ordinate, is sustained with a progressive burning powder for more than onethird the distance traveled by the bullet in the barrel, and, therefore, the energy storing means has coacted and relayed its energy to the bufling element during this time. The bullet leaves the barrel along with the powder gases at the maximum velocity obtained in the barrel, with the pressure. minimum. The muzzle brake or velocity dissipater, whether it be a reflection mechanism or retracting mechanism does not matter so long as advantage is taken of maximum velocity of the gas which emerged from the muzzle unit at a greatly reduced velocity, can serve only .to reduce recoil, due to the arresting of the forward velocity of the powder gases. r e

What would appear to be a fine. distinction between the present automatic gun and other automatic guns, using a portion of the powder gases for operating directly or indirectly, is, in reality, a very distinct difference, and has the same parallel as two moving objects racing each other in opposite directions.

The gas piston of the present type of automatic gun travels a distance greater than the length of the cartridge in a forward direction with no mechanical connection, or any other type of com-v munication between the gas piston and the bolt mechanism. In fact, during this forward movement of the gas piston, and the bullet travel in the barrel, no part of the mechanism of this gun moves to the rear, and the only reaction in the rearward direction is the base pressure on the cartridge case itself. The object of the gasesand piston moving forwardly from first thought, .will not be apparent to either the layman, engineer, or gun expert. The first advantage of prime importance is the delayed action, i. e., allowing the bolt and breech lock to remain locked against the fired cartridge, with no linkage whatsoever to start the unlocking until a considerable period has elapsed after the bullet has left the gun. This insures the dissipation of the entire base pressure in the fired cartridge case so thatno strain is placed on either mechanismor cartridge case when extraction is performedx This also assures a positive sealing of-the chamber which reduces erosion of the bullet seat, and the mech anism of the bolt; theprimer is firmly supported until all pressure has left the cartridge case; and no leakage around the primers can occur, a most serious defe'ct found with other automatic guns in general. The main disadvantage with leaky primers is the highly erosive efiect of the primer gases on the face of the bolt which destroys the usefulness of the bolt, the most expensive component of automatic guns. Leaky and blown primers are a source of endless trouble with automatic guns. In automatic guns in general, this condition is greatly aggravated by attempting to extract the fired cartridge case before the pressure in the case has been eliminated or dissipated.

Again, it might be apparent, on first thought, that the selection of the port for tapping the gases from the barrel should be at a point of maximum pressure and maximum temperature. The art does not show this, and until a very recent date the art could not have shown this, as no progressive burning powders were available, and were not available during the period of development of a single automatic weapon, regardless of caliber, in use at the present time by any country in the world. It was only natural, in the analysis of present-day requirements for an automatic gun that this most important factor should have received serious consideration. It is well known in the art that the powder curve for quick burning powder, which was the only powder in universal use until a very recent date, has a maximum ordinate, a very short distance from the breech of the barrel, and which diminishes most abruptly and is practically spent as to pressure and ordinate value before one-fourth the length of the barrel has been reached.

vantage to be obtained with energy available from the powder curve of a progressive powder, the analysis was continued to determine the energy that should be taken from the energy available from the powder charge, without diminishing the available energy under the powder curve. 7

The second consideration naturally followed to determine thepoint at which the gases should be tapped in order to have the gases deliver their energy to the piston and communicate it to the counterrecoil bufllng elements. This point hav ing been determined, namely, the point at which the. maximum ordinate appears on the powder curve, less the dimension forwarded on the power curve found necessary to handle the heat effect from the powder gases, it. still had to be deter- -mined what" timing was necessary to insure that the counterrecoil-element (which is an energy dissipating element acting in a forward direction) was sov applied that it would be co-acting with the base-pressure (the element which contributes to the recoil of the gun). This was determined and verified and the counterrecoil restraining members were calibrated to withstand twenty-five percent. less energy than is exerted by the counterrecoil elements. The acid test is: Will the breech lock remain locked after the restraining cap is broken, or will it unlock'before the cap is broken? Should the breech remain locked, it would mean that the base pressure (recoil source) would have been exerted, and the free recoil found would be approximately the equation shownbelowzn C=Weight ofv powder charge W=Weight of gun P=Weight of bullet V=Velocity of bullet VF=Velocity of freerecoil were co-acting for the reason that the energyused' in the counterrecoil element is very similar in comparison to that available in the borelof the gun. Again, the weight of the parts of the counterrecoil element that has moved in a forward direction is roughly times the weight of the bullet, so it can be seen that velocity acquired by these parts is extremely low as compared to that acquired by the bullet; and'yet, the velocity of the counterrecoil parts moving in the forward direction will be more than 10 times the velocity acquired by the mass of the gun tending" to move in the rearward direction due to the base pressure, as the ratio of weight of the counterrecoil parts moving ina forward direction to the weight of the gun is less than 1 to 40.

It can be readily .seen that atremendous ad vantage is to be gained as the velocity contributes ordinate and highest temperature, as well asmaximum pressure, and when the velocity is increasing, makes available a temperature-pressure energy component acting in a forward direction, which is dissipated in the forward direction.

This unit is utilized as part of the counterrecoil element as the velocity is relatively lower. A dissipation of the temperature and pressure results in an energy component in the forward direction which also is co-acting with the base pressure exerted in the opposite direction. The energy used for counterrecoil must be coordimated with the time of application, nature of application, the heat and pressure to be dealt with, and coordination with the utilization of the velocity counterrecoil unit, which is distinct and apart from the pressure-temperature unit, of counterrecoil, but is so closely associated with and 'co-acting that the total counterrecoil available and base pressure must be considered together when the maximum counterrecoil is to be expected.

From the foregoing, a clear distinction can be seen between this new type of gas energized mechanism, mechanically operated, and the conventional existing strictly gas operated automatic guns. The conventional type not only develops the hammer blow as its operating component, but exerts this hammer blow at the most critical time of operation so as to create the greatest disturbance to offset stability and, in addition, adds to the recoil of any automatic weapon.

It can be readily seen that when a piston is caused to be driven to the rear it must be arrested, whether it be arrested through a toggle link, a buffer, or both. This is bound to be coacting with a base pressure in the same direction. or otherwise the gun would not operate. To verify this, it is only necessary to fire a very few shots from an automatic rifle which will demonstrate the inability of the marksman to hold the rifle on the target, due to this gas operating element being driven to the rear and returning with the same disturbing effect, as the return occurs after the pressure or recoil has reduced and caused the gun to be displaced below the normal aiming point, whereas a movement to therear causes a disturbance above the aiming point. Again, one of the most disturbing'efiects is the fact that automatic fire builds up-the recoil and is actually greater after the seventhor eighth shot is fired than when the first shot is fired. This is true for the direct acting gas operating guns due to the fact that all direct acting gas operated guns do not dissipate the recoil between each shot. The blow exerted to operate the gun, therefore, is not dissipated for each shot,as the dissipation can only be acquired with a decided delayed action and with the operation element exerting a forward force and not a backward force. I e

Another consideration is the offsetting of the disturbing effects of recoilingand counterrecoiling units of the gun. To accomplish this, automatic guns of the past have used steep ramps or cams for braking the energy stored in the parts, which, in some cases, arecombined with the locking' element, This phase of automatic guns has been thoroughly analyzed and, in'the present gun, steps have been taken to overcome this most serious defect.

The arresting of the recoil and counterrecoil parts with the line of action a considerable distance from the bore of the gun is entirely overcome in the present gun by the provision of a power storing means so that the gun can be operated mechanically,

advantage having been taken of the mechanical operation to disconnect the operating power to overcome the hammer blow exerted with recoil barrels, and it is also disconnected after the full stroke is completed. The surplus energy necessary to insure operation under variable friction conditions clue to temperature, lack of lubrication, dirty mechanism, defective ammunition. burrs, etc., is not absorbed by a bu fling element whose application or action line isa considerable distance from the axis of the bore, but is absorbed by a bumng element directly connected to the barrel, placed in as close proximity as possible. In the first place, this reserve energy is cut to a minimum as it is not necessary to store sufiicient energy to return the barrel to battery or to return elements to the forward position that have any appreciable weight in the present gun. This is a most important factor when automatic guns are fired at an elevation. Again, the mechanical operation, as against the action of a blow, insures uniform regulated speed of fire of the gun. The necessity for locking and unlocking the breech lock with a steep angle is eliminated as the locking means is not used in the present gun for braking the recoil or counterrecoil force. Indeed, the reverse is true, as the locking element is not used for arresting the recoil and counterrecoil force. It is actually cushioned to overcome any tendency to lock and unlock with a harsh or blow action. This feature alone, makes it possible to use a very fiat angle of locking, an angle slightly above the friction angle, whereas all automatic guns in existence use an abrupt angle of 40 or more, which not only exerts unnecessary strains on the mechanism, but disturbs stability of the mechanism and causes excessive wear and breakage of parts. In the original study and analysis of the specifications of the present automatic gun, an exhaustive investigation was made of the methods of presenting the breech lock to the locking recess in the frame. The best comparbe summarized as follows:-

To provide a lock which will be locked with the least shock and yet be positive. To have the lock travel as near as possible at the same velocity at the time of looking as that of the bolt, and to have the lock take up the velocity of the bolt just before and during unlocking.

Practically all automatic weapons in existence use a breech lock that is entirely stationary, or one that is moving with an extremely low velocity as compared with the velocity of the locking element with which it mates.

In the present gun, the breech lock is carried with the bolt. The parallelism is exactly the same as would be encountered in moving a given weight, a definite height on a high speed train, as compared with the same weight moved the same height by the same person attempting to raise it from a mail-bag arm. Some automatic weapon designers resort to a method of locking by rotating the bolt after it has reached its forward position. While this method has some ad- 'ison of the trend of thought on this subject can vanti' ges over tl te method of lockinga stationary-g-breech lock, it has-a disadvantage in that it j is'necessary' to overcome the energy of translation before energy of rotation can be accomplished- To do this, the locking angle must be extremely'steep to break the force of the damaging eflect'jhat would be encountered in atagainst the cartridge, the breech lock, in attempt-v ing to continue its path, gains the forward face of the breech lock guide of the'bolt, which'is m the position to present the breech'lock' to'the' locking recess against its'forward face, and not its rear face. To prevent pinching or wedging and to insure positive locking in case of an oversize cartridge, the rear face of the breech lock and of the breech lock recess are provided with. a

slight angle to give clearance in locking and to obtain wedge action inthe flnal stage of locking. Furthermore, the advantage to be gained with a flat angle of the locking'carn is that the resultant of this lockingeffort i's more nearly parallel with the base pressure and, consequently,'is not a disturbing elementv as to stability. The locking element of the present automatic gun is a most powerfullocking means, yet a locking element that requires the least locking .eflfort, thus making it possible, and n i g has been taken of this, to cushion .thelocking element. 1

' the action-of the'mainspringj; The frog is the v driven member, the main, spring is the driver, and

the piston rod. The rear'endof Qthe pistonIr'od -In analyzing the 'preliminary design of the present automatic gun, serious consideration was given tothe eifects of they carrying and carried .parts.; When the gun is flred,,-the' gas piston I carrying the cross-head and clutch compresses the main spring and is finally-arrested byv the counterrecoil bufling element. No part of the receiver mechanism is in motion duringj this reached its forward position; the' clutch engage which isagainst the frogtransmits the energyl of the main spring to the-frog when thefrogi' moves to therear, the bolt-an 'jbreech lock .as a unit are carried to the rear'by the frog under.

the breech .lock iscamrned-jdown and heldfin the: depressed position, as theretarding effort, 1'

of the bolt tends to keepthe breech lock in its; lower position. vAs the bolt is driven'to the rear,"

'theboltsspring is compressed and the bolt and:

frog'are'finally,arrested-byfthe action of the f regulating "buffer. Thei regulating buffer can be,

throttled tog'overn the rate of r e'coil as the main spring exerts a constantlyfapplied,iforce which Y is distinctly different from'th'eblow'rebeived by the bolt element of a directly gas operatedgun or a operated from a b ow transmitted bya reiqlling hamll i m ides n extreme simple-speed regulating,;absorbing elementfl.f

In seth er-is pulled. ,andreleased,.'a

single' shot can be fired, either withtlie m ch nism held in the retracting position,'= or Iwith the" mechanism closed on a' :cartrid'ge;=,as'desired This featureis verydmportant, 'fa's no automatic. gunx provides both an' automatic 'Iretracted arrester and a closure on a' cartridge withoutflfir ing. This feature is also of extreme importance .to continue the fire immediately without mechanical manipulation. When thefbolt has reached the rearward position and the trigger is held pressed, the bolt becomes the driver under the action of the .bolt spring, and the frog the driven member.

When the cross-head, which. carries the clutch, reaches its rearward position, the clutch disengages when the clutch pawls come in contact with'the front face of the frame. I This permits. the cross-head and the gas piston to move to the rear position ready for the next shot, at the same timeeliminating the necessity of re+ turning the clutch to the forward position by the bolt spring, which spring performs this function with a majority of the present automatic gunsf The inertia of the frog, when returned by the bolt, causes it to lag behind the bolt which maintains the breech-lock in the lowest'position, eliminating any friction drag of the breech lock which would be encounteredif any tendency to lock were present. The frog in going forward, returns the piston to the forward position through the cross-head, the clutch having been cleared by the clutch pawls.

' T'I'he present automatic machine gun has been provided with a simple but highly efficient safety. It is of extreme importance when firing. larger caliber shells with supersensitive fuses, and of equal importance with any caliber, thatthe gun shell, or portion thereof into the chamber... The same isfltrue should a cartridge be fed intothe chamber ahead of the bolt, T-slot, or extractor, e and; consequently, fail to fire The bolt must be part of the cycle. When thejcross-head has,

retractedfito. clear-such a jam. This retraction 11 the chamber, would be disastrous-results} With the present automatic orni'allyfeeds the next cartridge into alignment th .the 'bore. I Inv the case, of asolid shot,'t'h e rimerfof the live round in "the chamber will fired withvno'supportfor the base of the cartridge to prevent anexplosion with ill consequences, re-' 'sulting inpthedestruction of thegun crew and gun should asupersensitive fused cartridge be machine'fgun', the safety-block" operates to' prev'enti'thi's accident. [The safety block covers'a portion o'f 'the c'hamberat all timesfwhen the 'ichamber is empty." Consequently, any obstructio'n inwthe'chamber, such as a shell orfcartridge', willforce the safety block down, -which raisesthe rear-end of the safety lever, thus engaging the bolt on the rearward stroke and arresting the bolt, 'which prevents'the feeding ofanother car-wf triage. until the chamber hasbeen cleared, Nat'-. I

urally, thesafety block, does not act when I the gunis functioning no mallrjas the bolt itself clears'the obstruction and allows the safety block toraise and lower thejsafety lever outioffthe' pathiof the lug of the bolt. Bycarrying the breech lock. with the bolt, two

additional safety features aremade possible. One

is .an extension on the, upper portion of; the 75 f breech lock that straddles the firing pin head. This extension is provided with a recessed slot, which positively prevents the firing pin from striking the primer until the bolt is completely locked and, in addition, serves to move the firing pin to the rear, clear of the primer recess made by the firing pin, immediately after unlocking begins. In addition, it permits the separation of the sear and sear carrier unit, and causes each to operate separately, yet both depending entirely on the completeness of the locking of the bolt for their release. This design also permits the looking to be accomplished directly in line with the base pressure, as contrasted with the existing types which lock a considerable distance below the actual line of the base pressure and create a turning moment, which disturbs stability.

The counterrecoiling element of the present automatic machine gun takes advantage of new discoveries made in this field and coordinates these discoveries into a simultaneous co-acting couple. The velocity brake at the end of the muzzle is not new as to the killing of the velocity to obtain reduction in recoil. However, what is entirely new in this field is a mechanism so constructed as to present the gases in a uniformly distributed way to the bathing elements so as to obtain the maximum recoil reducing effect, and at the same time to provide a mechanism that will not be obstructed with carbon or residue or other'deposits from the firing, and one in which no disturbing force is presented to make the gun unstable, to defiect gases, or direct intense noise and powder gases into the path of the personnel operating the gun.

To provide a stabilizer, in this instance, a central tube is used to overcome the present distortion of the bullet due to the unequal distribution of gases about the base of-the bullet, present in all existing recoil muzzle checks, whether they be spiral baflles, direction slots, expansion or contraction chambers with other corresponding escape vents. Some investigators go so far as to claim that these muzzle brakes or recoil checks stabilize the gun by a positive reaction in one or the other direction. The answer to all of this is to so design a successful automatic weapon that the entire action and reaction shall be in one-and the same straight line, as a most efficient application of any force is the one applied directly in line with the resistance to be overcome with no deflection in the force arm. The forward pull of the muzzle recoil reducer in the present instance acts in this direction.

With the foregoing and other objects in view, which will appear as the description proceeds, the invention resides in the combination and arrangements of parts and in the details of construction hereinafter described and claimed, it being understood that changes in the precise embodiment of the invention herein disclosed can be made within the scope of what is claimed without departing from the spirit of the invention.

In the accompanying drawings:-

Figure 1 is a side elevation 01' the complete gun made according to and embodying the present invention, the tripod or mount not being shown, and the water or cooling jacket also being eliminated.

Figure 2 is a top plan view of the rear end of the gun, the barrel being foreshortened.

Figures 3 and 3" constitute a longitudinal central sectional view through the receiver portion of the gun and a portion of the barrel, with the parts in the position they assume just after the firing of the cartridge and the setting of the power spring of the gun.

Figures 4 and i are views similar to Figures 3 and 3 with the parts in the position they assume at the fully retracted movement of the breech block and during the ejectment of a spent cartridge from the receiver, and just prior to the introduction of a new cartridge into the breech.

Figure 5 is a rear elevational view of the breech end of the gun.

Figure 6 is a section taken on line 6-6 of Figure Figure 7 is a section taken on line '|'I of Figure 3.

Figure 8 is a section taken on line 8-8 of Fi ure 3.

Figure 9 is a section taken on line 99 of Fi ure 3.

Figure 10 is a section taken on line Ill -l0 of Figure 3.

Figure 11 is a section taken on line ll-ll of Figure 3 Figure 12 is a longitudinal sectional view taken on line i2-l2 of Figure 7, and on line l2'l2' of Figure 8.

Figure 13 is a section taken on line Iii-l3 of Figure 10.

Figure 14 is a section taken on line ||i4 of Figure 8.

Figure 15 is a view similar to Figure 3 of the receiver end of the gun, showing a modified searactuating and operating mechanism.

Figure 16 is an enlarged detail view of the searactuating mechanism in the position it assumes after just releasing the sear.

Figure 17 is a section taken on line li-ll of Figure 15.

Figure 18 is a section taken on line l8l8 of Figure 15.

Figure 19 is a sectional view through the receiver showing the manual releasing sear-actuating mechanism in normal position.

Figure 20 is a similar view showing the mechanism in the position it assumes when retracted and prior to the release thereof.

Figure 21 is a detail longitudinal sectional view through the muzzle dissipater.

Figure 22 is a section on line 22-22 of Figure 21.

Referring to the drawings, in which like reference numerals represent similar parts throughout the several views, and in which, in Figure 15, the primed reference numerals represent similar parts as shown in Figures 3 and 4, the numeral I designates the barrel proper of the present gun and 2 the receiver. The gun is supported by means of the trunnions 3 and the yoke 4 on a tripod T and is supported at its rear by the lug 5 and theadjusting screw 6 operated by the elevation control wheel I. The present type of gun is also constructed to be mounted upon any form of mount, as it can be used as a tank or antitank gun, as well as an aircraft or anti-aircraft gun.

A magazine 8 is adapted to feed the cartridges C into the receiver, and although here shown as a casing, the same is indicative of a belt feed mechanism. The barrel 9 is fitted into the supporting portion 6! of the receiver, as at l0, being provided with the breech II for the reception of the cartridge C, the cartridges being fed into the receiver through the opening i2.

A breech block l3, which is capable of straight line reciprocating movement within the receiver and is mounted for sliding movement between the strips I4, is also provided with the oppositely disposed end guiding lugs l6. Mounted within and carried bodily by the breech block is the firing pin ll which is normally propelled forward by the spring l3 so that the fulminate cap-engaging end l3 may be projected through the opening 20 of the breech, block to engage the fulminating cap of the held cartridge C. The rear end of the firing pin is adapted to be projected beyond the rear space of the breech block so that its head 2| willbe in the path of and be automatically engaged by the shoulder 36 of the automatic sear 33 which is mounted for vertical sliding movement within the recess 32 of the receiver and is held downwardly in place by means of the spring 34 and the cap 35.

Also associated with and carried by the breech block are the cartridge extractors 22, the forward ends 23 of which are disposed forwardly of the breech block for engaging the rim of the cartridge C while the same is within the breech and to be automatically actuated to withdraw the same upon the rearward movement of the breech block, so that when the empty case is alined with the members 24, as viewed in Figures 8 and 14 the portions 24" thereof will be projected outwardly and above the case to cause the same to be ejected from the receiver. These members 24 are mounted in the oppositely disposed casings 25 and are normally held outwardly inthe path of the breech block by means of the springs 26, the forward movement of said breech block retracting said members within the casings, while the rearward movement permits the springs 26 to act as above set forth.

The breech-block is provided with the lug 21, the purpose of which will presently appear, and with the open depending member 28 which constitutes a guide for the lock 23 and is of vast importance. The lock 23 is provided with the abutting portion 30 disposed to be placed, at the proper time, between the rear end of the breech block and the portions 30 of the receiver so as to momentarily lock the breech block against rearward movement and during the engagement of the sear-releasing device 3| can'ied thereby, which, as shown, is adapted to enter the opening 32 and elevate the automatic sear 33 so that the portion 36 thereof is moved out of engagement with the head 2| and, consequently, release the firing pin simultaneously with the final locking position of the bolt. Thus, it will be seen that the lock 23 is carried bodily by the bolt or breech block in its reciprocating movement and is only brought into locking engagement shortly after the retraction of the firing pin by engagement with the automatic sear 33 and the release thereof for exploding the fulminating cap. 7

To assist in the forward movement of the breech block, a casing 36, open at one end, is held within the member 28 by means of the lock nut 31, and bodily disposed within this'member is a 7 tube 40 provided at its free end with the plunger or piston 4| fitting within the cylinder 42 fixed at 43 to the rear end 44 of the receiver.

Mounted within the telescopic members 40 and 42 is the auxiliary spring 45 which acts to move the breech block into breech-closing and locking position, the same being abutted by the shoulder I; carried by the guide pin 41 and housed within the casing 46 detachably connected at the rear end of the receiver and upon the end 43 of the sleeve 42.

Mounted within the casing 46 is a plunger 43 which is held forwardly by means of the spring 50, while mounted for adjusting the rod 41 is a milled finger wheel or button 48, the purpose of which will presently appear.

Connected to the barrel 3 forwardly of the receiver is a band 5| which. as shown, has secured therein the rear end of the cylinder 52, and has a port 53 leading from the bore of the barrel 3 into the rear end of said cylinder so that the gases issuing therefrom act upon the piston 54 to move the piston forwardly, the purpose of which will presently appear. This piston 54 is connected to the forward end of the rod 55 which is thread edly engaged at 56 to the cross head 51 slidably mounted and guided by the barrel 3 and'the guide rod 53, said guide rod 53 being mounted throughout the opening 58 of the cross head 51 and attached, as at 66, to the member 5|. The rear end of the rod 53 is mounted in the solid portion 6| of the receiver and the entire mechanism at this point is surrounded by a casing 62.

As shown in Figures 3",8Ild 10, the forward end of the rod 61 is connected to the cross head 51 in an unusual manner, there being disposed in the bore 63 the inwardly moved blocks 65 whose springs 65 engaging theblocks 64 hold the inner ends thereof in the path of the rod 6'! to be en:- gaged thereby, the purpose of which will presently appear. The ends 66 of the lock 65 are disposed, as shown in Figure 13, to abut the end of the rod 61, and attached to this rod are the two pins 68 which slide within the openings 63 of the bifurcated members 10.

Attached to the rear end of the rod 61 and adapted to be movable with the same at all times is a link R carrying a setting pin I2 and a bifurcated end 13, each member of which is provided with the angular rectangular recess 14, and a sear 15. A pin 1'! is mounted in the locking block 23 and is engaged at its ends by means of the rectangular blocks 16, said blocks 16 being mounted within the openings 14 so that when the link R is 'reciprocated, vertical reciprocating movement is imparted to the locking member 23.

In order to pull the link R and-also the breech block |3 rearwardly against the action of the spring 45 to initially set the present mechanism before the first cartridge is fired, the rod 13 is r pulled manually rearwardly through means of the eye 13 so that the hook terminal 80 will engage the pin 12, the same being pulled until the catch 15 engages the trigger 8|, at which time, the breech block and mechanism is locked in full rearward position and the spring 45 is placed under tension. The trigger 8| is mounted within the casing 82 formed at the rear under side of the receiver and is itself provided with a recess 63 for the reception of the rounded end 84 of the trigger or hand-operated member 35 mounted on the pin 86 at the upper portion of the hand guard 8'Iand in ready access to the operator of the present gun.

Connected to the forward end of the rod 55 is a rod 83 which is mounted to move within the forward extension 30 of the cylinder 52 and against .the action of the spring 3| to abut, at the final 'member 83 is taken care of by the buffer 32 at the extreme engagement of the piston 54 and just Gil imer the escape of the gas through the openings 80 (Fig. 3).

Mounted within the receiver to be engaged b the projection 21 of the breech block is a pivoted lever 94 mounted upon the pin 95 within the receiver and provided with the rear weighted portion 36 so that the member normally assumes the position as shown in Figure 4 for movement to the position as shown in Figure 3 by the engagement of the lug 21 therewith so that the forward rounded end 01 mounted within the bore 08 of the plug 99 will move the-block I00 to the lowermost position and against the action of the springs I05 which hold the pin through its head I03 upwardly within the bores I04, so that the safety block I00 will move to assume the position as shown in Figure 4. Thus, should a shell remain within the breech of the barrel, the introduction of a new cartridge therewithin will be prevented and the mechanism will be locked against further movement. In the construction illustrated in Figures 15, 16, 17, and 18, a modified arrangement of scar is shown mounted at the top of the receiver covered by the lid I06. This comprises a double lever I01 mounted in place by means of the pin I08 between the ears I09 thereof, and mounted in the forward end thereof, in the recess III, and held against upward displacement by means of the plate I I I, is a catch or bolt I I3 propelled downwardly by means-of the spring I I2 for engagement with theedge II 4 of the sear 2I' of the firing pin. Also, to assist in moving the lever I31 from locked position, as shown in Figure 15, to released position, as shown in Figure 16, in the free end of the lever I01 two pins II5 are carried, which pins are spring-propelled by means of the spring II 1 so that their lower ends will engage the upper portion of the lugs II5 carried by the locking bolt 30'. Thus, it will bev seen that when the locking bolt is elevated into breech-locking position, the members I I5 will engage the pins H5 and thus automatically elevate the free end' of the lever I01 so as to release'the firing pin,

In order to provide a means whereby this release may be performed manually, the rear end I IQ of the lever I I1 is adapted to be "engaged by the portion I20 of the sliding bolt H8 mounted abovethe receiver and within the rear end of the lid I05. This is accomplished through the instrumentality of the slot I2I and the head I22 of the bell-crank lever I23, which lever is mounted upon the pin I24 between'the projections I25 of the receiver and is manually operated through the pin clearly shown in Figures'l9 and 20 in which a lever I23 with a hand-piece I is mounted for pivotal and sliding movement through the instrumentality of the slot I3I and pin I32 at the right-hand rear side of the receiver. its forward hooked end I34 being disposed to be projected through the opening I against the spring I36 so as to engage the hook I31 attached to the block 2|" ofthe firing pin I1. By this means,

the firing pin may be movedfrom the position;

I31. This operation may be repeated any number of times.

In the construction of muzzle dissipater shown in Figures 1, 21 and 22, the outer casing I30 is providedzwith a central tube 'I3I which acts as a; guide for the bullet with perforations I32 therethrough, said tube providing a chamber I34 at the inlet end outletting at the periphery I35 between the outer edge of the spiral I36 and the inner face of the casing I30. Thus, the gases emitting from the muzzle are directed into the chamber at the inner end thereof, and are diffused through the spiral chamber, the perforations of the tube and the tube so as to act asa brake at the muzzle of the gun.

By having the spiral disconnected at the pe riphery with the inner walls of the chamber, collection of carbon or dirt is prevented, and'th'e same'is finally carried out through the outlet 1 of the dissipater.

As shown in Figure 15 of the drawings, themember 5', as the bolt 30" is elevated into locking uosition at the rear of the breech block I3" and after the final locking of the same, engages the free end of the lever I01, and thus releases the sear so that the firing pin is released to explode the fulminating cap. This particu lar construction dispenses with the link I21 and the parts operated thereby.

' I claim:--

1. A machine-gim including a receiver, a barrel connected thereto, a breech block reciprocatingly' mounted within the receiver for straight line'movement to and from the breech of the barrel, a spring propelled firing pin bodily carriedby the breech block, a fixed locking member mounted in the receiver, a vertically movable lock bodily carried by the breech block for cooperation with the fixed member when the breech block is in breech-closing position, means for retracting the firing pin during the closing of the breech, the same being released to freethe firing pin by the movable look as the latter completes its f final locking movemeniyand a device-connected tothe breech block for causing limitedv sliding movement of the movable lock, whereby the lock is'released before the breech block is started on its rearward movement.

2. Amachine-gun including a receiver, a barrel connected thereto, a breech block reclprocat-. .ingly mounted within the receiver for straight line movement to and from the breech of the barrel, a spring propelled firing pin bodily carried by the breech block, a fixed locking member mounted in the receiver, a vertically movable lock bodily carried by the breech block for cooperation with the fixed member when the breech block is in breech-closing position, and a device connected to the breech block for causing limited sliding movement of the movable lock,whereby the lock is released before the breech block is started on its rearward movement, gas-set and spring-actuated means mounted in the receiver and connected to said breech block for imparts ing rearward movement to the breechblock, means mounted in the receiver and in the path to engage and set the firing pin as the breech block ismoved in to closing position, said'means oeing released by the movable lock when said lock is moved into final locking position, and a spring compressed during said rearward move- .ment to impart forward and closing movement to the breech block after releasing of the first r I I 3. A' machine-gun, including a receiver, a bar I second spring to set the'same. I v

5. A machine-gun, including a receiver, abar-. rel connected thereto, a breech block reciprocatinglymounted within the receiver Iorstraightline'movement to and irom the breech of the 1 barrel, a fixed lockingmember mounted in' the receiver, a movable lock bodilycarried by thebreech block for cooperation with the fixed lc ick-k ing'member when the breech block is in breech closing position, gas-set and. spring-actuated; means connected to said bree'ch block for imparting rearward movement'to thebreech, block, a; spring compressed during rearward {movement to impart forward and closing movement to, the the first spring, inv prevent the closing of a misfire and ,a spent cartridge. shell remains in the breech of. thebarrel.' .55

spring-propelled firing pin "carried bodily .byz th I lock forjreleasingthe firing pin M I ingot the breech block, and manually controlled I ingly mounted within the receiver for straightlinemovementto and from the 'breechotthe barrel, a fixed locking member mounted'in the receiver, a movable lock bodily carried byfthe;

breech block for cooperation with the fixed'lo'cking member when the breech block lain breechclosing position, i gas-set spring;actuated means connected to said breech block 'forimparting rearward movement to thebreechiblock,

a spring compressed during rearward movement to impart forward andiciosing movement to I the breech block after release'of the firstispring, a spring-propelled firing pin carriedbodily by the breech block, means for coincidentally setting the firing pin at the close of the breech by the breechblock, and means carried by the movable -member of the lock vi'or'releasing the same at the final locking of the breech block.

4. A machine-gun, including a receiver, a barlinegmovement 'to and from'the breech ofthe barrel, a fixed'locking member mounted in the means connectedto said breech block for imparting rearward movement to the breech block, a spring; compressed during rearward movement to impart forward and closing movement tothe breech block afterrelease of the first-spring;

manually operated means is provided for moving' the breech block against the action of the breech block after release of which means is provided to, of the breech block in case 6. Amachine-gun including a.receiver, a- ,b arfrel connectedthereto, a breech block.reciprocatreceiver, for straight I H v recoil actionto thefgilni 7 .l3.- An automatidgunaccording to claim 1, in

barrel, a fixed locking member'mounted infthe' receiver, a movable I lock bodily carriedfbfth breech block for cooperation withthefixedjnie her when the breech block is in breech-clo'sin position, gas-set and spring-actuated means'cdn-' nected' to said breech jblock compressed 'during said rearward *mover-n ntTt impart forward and closing breech block after release of the first spring,

breech block, means. for ,coincidentailyfisett means c'arried by the movable member-crime at thefinal ack;

for setting and, releasing, the" recoilactlon tothe'gun; a l

' powder curve is vat its maximum, ,returned plunger mounted in the tube and oper- V I r for imparting 'jreare wards movement to the'breech blockia sp ng' movement" ohe after the "same has, been automatically released and the breech block is still in locked position.

*7. 'A machine-gun according to claim 6 in which there is provided a means for locking the breech blockagainst closing action due to the retention inthe breech of a deformed cartridge casing.

from the breech of the barrel, a locking member carried by the receiver, a slidable locking member carriedby the breech block, and cooperating means carried by the slidable locking member and plunger-'actuatedirod for imparting vertical reciprocatingmovement'to the locking member during the locking and unlocking of. the breech block.

91A machine-gun according toclaim 8 in which there is a spring iopposing the rearward movement of the breechblockiand for propelling the breech block into breech-closing position and for moving -me locking member carried thereby into "locking position, av firing pin'carried by the breech block; meansdis posed in the path of the firing pinfor 'settin'g'the same during the closing of the'breec'h'block, and means carried by' 'the movable locking member for releasing the firing pin whenthe breech block is fully locked.

.10. An automatic gun according to claim 1, in which there isa tubewdisposed parallel with the barrel'and in communication with-the bore of the'barrel at a pointwhere the ordinate of the powder curve is at its" maximum, and a spring returned plunger mounted in'the tube and operated in aforwarddirection by the gases of explosion admitted tothe tube to produce a counter- 11. automatic' gun'according to claim 6, in

hich there is a 'tlibe disposed parallel with the barrel" and incom'munic'ation with the bore of the barrel at a point'where' the ordinate oi the and a spring atediina' forward'direction by thegases of explosion admitted to thetubetoproduce a counter- V recoil action to the'g'gu'n 12. An automaticgun according to claim. 8, in

J which there is. a, tubeqdisposedfparallel with the barrel and-ln communication with the bore of the barrel at a point where the ordinate of the powder curve isjatf-its' maximum, and a spring returned plunger mountedin' the tube and operatedin 'a'forward'I-direction byfthe gases of explosicn'a'dmitted-to the tube to producea counterwhich'lthere isa' tube disposed parallel with the the.

powder. curve; is at its maximum, a spring returned plunger mounted in the tube and operated in' ai forward direction by the gases of explosion the muzzle of the barrel'and upon which the gases-of" explosion actin cooperation with the plunger to produce a counterrecoil action to the 8 J i [14. An automati'c gun according to claim 6, hichith'ere is -a' tube disposed parallel with e. 'barrel and in jcommunication with the bore 0i' the barrel; at'apoint where the ordinate of theipowder curve i's'at'its maximum, a spring revbarrel "andQin:{communication with the bore' of I barrelat a point-where the ordinate of the admitted to'the was, and a braking device at in the receiver for "straight line movement to and turned plunger mounted in the tube and operated in a forward direction by the gases of explosion admitted to the tube, and a braking device at the muzzle of the barrel and upon which the gases of explosion act in cooperation with the plunger to produce a counterrecoil action to the gun.

15. An automatic gun according to claim 8, in

which there is a tube disposed parallel with the barrel and in communication with the bore of the barrel at a point where the ordinate of the power curve is at its maximum, a spring returned plunger mounted in the tube and operated in a forward direction by the gases of explosion admitted to the tube, and a braking device at the muzzle of the barrel and upon which the gases of explosion act in cooperation with the plunger to produce a counterrecoil action to the gun.

16. A machine-gun including a receiver, a barrel connected thereto, a breech block reciprocatingly mounted in the receiver for straight line movement, a fixed locking member mounted in the receiver, a movable lock bodily carried by the breech block for cooperation with said fixed member when the breech block is in breechclosing position, gas-set and spring actuated means connected to said breech block for imparting rearward movement to the breech block, a spring compressed during said rearward movement to impart forward and closing movement to the breech block at the release of the first spring, a spring propelled firing pin carried bodily by the breech block, means for coincidently setting the firing pin at the closing of the breech, and means carried by the movable member of the lock for releasing the same at the final locking of the breech block.

17. A machine gun according to claim 16, in which there is provided a means for locking the breech block against closing action due to the retention in the breech of a deformed cartridge casing or a misfire.

18. A machine gun according to claim 16, in which there is a tube disposed parallel with the barrel and in communication with the bore of the barrel at a point where the ordinate of the powder curve is at its maximum, and a spring returned plunger mounted in the tube and operated in a forward direction by the gases of explosion admitted to the tube to produce a counterrecoil action to the gun.

19. An automatic gun, including a receiver, a barrel attached thereto, a breech block mounted in the receiver for movement to and from the breech of the barrel, a spring propelled firing pin carried by the breech block, a gas-set and spring returned plunger mounted adjacent to the barrel, means for determining the amount of power stored in the spring independent of variation of powder pressure, a rod mounted for reciprocation within the receiver, and cooperative means carried by the rod and the breech block whereby the breech block and rod are permitted independent forward movements and whereby the rod will move the breech block rearwardly when the plunger and rod are spring propelled, and means for setting the firing pin mounted in the receiver, the latter being released at the final closing of the breech block.

20. An automatic gun according to claim 19, in which a tube is disposed parallel to the barrel and has a port in communication with the barrel, the plunger being mounted in the tube, said port being at a point where the ordinate of the powder curve is at its maximum.

21. An automatic gun, including in combination a receiver. a' barrel attached, thereto, a breech block mounted in the receiver for straight line movement, a spring propelled firing pin carried by the breech block, means for reciprocating 5 the breech block, means carried by the receiver in the path of the firing pin for setting the same as the breech block is moved into breech closin position, and means carried by the breech block for engaging the setting means to release the firing pin.

22. An automatic gun as claimed in claim 21, in which manually operated means is provided for retracting and releasing the firing-pin independent of movement of the breech-mechanism.

23. An automatic gun as claimed in claim 21, in which means is provided for preventing the closing of the breech block and the introduction of a new cartridge in the breech of the barrel should a portion of a spent shell or a spent shell remain in the breech of the barrel.

24. In a gun, a receiver, a bolt, and locking and shifting means for the bolt in the receiver including a locking member, means for moving the locking member to operating and inoperating positions, said means having an inclined slotted connection with the locking member permitting the lock to have a movement independently of the bolt, but at a predetermined position upon shifting the bolt in one direction, and other means for forcing the bolt in the reverse direction whereby the slotted connection is maintained under pressure to hold the lock in retracted position to prevent movement thereof in a locking direction.

25. In a gun, a receiver, a bolt, and locking and shifting means for thebolt in the receiver mcluding a locking member, means for moving the locking member to operating and inoperating positions, said means having an inclined connection with the locking member permitting the lock to have a movement independently of the bolt, but at a predetermined position upon shifting the bolt in one direction, and other means for forcing the bolt in the reverse direction whereby the connection is maintained under pressure to hold the lock in retracted position to prevent movement thereof in a locking direction.

26. In a gun, a receiver, a bolt, and locking and shifting means for the bolt in the receiver including a locking member, means for moving the locking member to operating and inoperating positions, said means having an inclined loose connection with the locking member permitting the lock to have a movement independently of the bolt, but at a predetermined position upon shifting the bolt in one direction, and other means for forcing the bolt in the reverse direction whereby the loose connection is maintained under pressure to hold the lock in retractedposition to prevent movement thereof in a locking direction, the arrangement of the parts permitting the lock actuating means to operate under momentum when the bolt has been positioned in its return movement to move the lock into locking position relative to the bolt.

27. In a gun, a bolt having a straight line movement, means for actuating the same, and means for locking the bolt against movement comprising a locking member movable in a rectilinear path to have a substantial bearing at right angles to its longitudinal axis and substantially in line with the center of load to be applied thereto.

28. In a gun, a bolt having a straight line 7 movement, means for actuating the same, and means for locking the bolt against movement comprising a locking member movable in a rectilinear path to have a substantial bearing at right angles to its longitudinal axis and substantially in line with the center of load to be applied thereto, the rear face of the lock being wedge-like to crowd the bolt home when the lock is forced into locking position.

29. An automatic gun including a receiver, a breech block mounted for movement in the receiver, a movable locking member for locking the breech block in closed position, a spring-propelled firing-pin carried by the breech block, means for setting the firing-pin at the cloflng of the breech block, said lock releasing the firing pin upon locking of the breech block, and means for manually controlling the releasing of the firingpin independent of the locking of the breech block.

30. An automatic gun including a receiver, a breech mechanism mounted for reciprocating movement in the receiver, means for moving the breech mechanism to the rear, other means for moving the breech mechanism forwardly, a spring-urged firing-pin carried by the breech mechanism, means for setting and releasing the firing-pin upon closing of the breech mechanism, means for manually controlling the releasing of the firing-pin, and a manually controlled sear for engaging the breech mechanism when in its rearward position to hold the breech mechanism open.

31. An automatic gun including a receiver, a breech mechanism mounted for movement in the receiver, a spring-urged firing-pin carried by the breech mechanism, means for setting and releasing the firing-pin upon closing of the breech mechanism, means for reciprocating the breech mechanism to cause automatic operation of the gun upon the firing of a cartridge, means for manually controlling the releasing of the firingpin, and a manually controlled member for catching and holding the breech mechanism when in its rearward position.

32. An automatic gun including a receiver, a barrel attached to said receiver and having a gas port adjacent the breech end thereof, a breech mechanism movably carried in said receiver, piston means actuated in a forward direction by gases from said port, and power storage and counter-recoil abutting instrumentalities including the gas actuated piston means, a spring adapted to be compressed under the actuation of said piston means for storing power to operate said breech mechanism. a counter-recoil abutment fixed forwardly to the gun, means for eifecting a positive abutting relationship between the piston means and the abutment at the final stroke of the piston means, said abutment being substantially non-resilient and non-recovering so as to transmit to the ted parts of the gun the forward force of the piston means which is in a direction opposite to the recoil force of the gun.

33. In an automatic gun having a barrel, shell ejecting and re-loading mechanism, piston means associated with said m to actuate the same, a cylinder attached to said barrel and in communication therewith to receive gas therefrom, resulting from the explodon of a power charge, an abutment secured to said cylinder and energy storing means in said cylinder means, said piston and cylinder means and energy storing means being so related in said gun that said powder gases actuate said piston means forwardly of the gun-and transmit energy to said energy storing means, said energy storing means thereafter furnishing the energy to actuate the piston means and said mechanism; the combination of a substantially non-resilient abutment means between said aforementioned abutment and said piston means to limit the amount of energy stored in said energy storing means and whereby the excess energy will be substantially all transmitted to said gun in a forward direction.

ROBERT F. HUDSON.

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