US1005263A - Gas-operated machine-gun. - Google Patents

Description

S. N; MQCLEAN. GAS OPERATED MACHINE GUN. APPLICATION FILED FEB. 11, 1004.

Patented Got. 10, 1911.

4 SHLETS SHEET 1.

S. N. MGGLEAN. GAS OPERATED MACHINE GUN. APPLICATION FILED FEB.11, 1904.

Patented Oct. 10, 1911.

4 $HEETS-SHEET 2.

llWE/V rolf:

Mr/vEssEs:

WITNESSES:

S. N. MUCLEAN. GA OPERATED MACHINE GUN. APPLICATION FILED FEB. 11. 1994,

Patented Oct. 1%., 1911.

4 SHEETS-SEEET 3.

//v VEN 7013:

41, aim;

Patented Oct. 10, 1911. 4 SHEBTS-SHEET 4.

s. N. MQGLBMI. GAS OPERATED MACHINE GUN. APPLICATION FILED FEB. 11, 1904.

ESSES; 7H5 W4; WM

UNITED STATES" PATENT OFFICE.

SAMUEL McCLEAN, OF. CLEVELAND, OHIO, ASSIGNOR. BY MESNE ASSIGNMENTS, TO

' THE AUTOMATIC ARMS COMPANY.-

GAS-OPERATED MACHINE-GUN. f

To alt whom it may concern."

Be itknown that I, SAMUELN. llICGLEAN, a resident of Cleveland, Ohio, have invented a new and useful Improvement is Gas-Operated Machine-Guns, which invention is fully set forth in the following specification.

My invention relates to improvementsfin breech-loading discharge actuated guns, and

more particularly to gas-operated machine guns.

The objectof the invention 15 to improve and simplify the construction, operation and manufacture of these guns, to produce-again-having a small-number of operating parts, which can be easily cared for, as-

sembled and disassembled without tools, inv

which the parts canbe interchangeable and readily. removed and inserted; and to attain certain advantages in connection with the breech-mechanism, and in the feeding, firing and ejecting actions of the-gun, as more fully pointed out hereinafter.

The invention set forth in the accompanying drawings comprises a'gas-operated ma.- chinr-gun having a reciprocating and r tating ln-ecch-block engaged by a gasdriVen piston to operate the breech mechanism, and

provided with an air-cushion to check the terminal movement of the piston and to control the speed of tiring. The piston-rod also cnga and operates an oscillating cartridge feed to consecutively feed the cartridges,

and cooperates with a scar and trigger to control the firing action of the gun. The frame of the gun is provided with a vertical magazine for retaining and consecutively feeding the cartridges, and this feed is provided with spring-pressed feed-fingers en-' gaging with the cartridges to retain and control the consecutive feeding action of the cartridges.

Figure l is a side elevation of the gun, showing the rear part of the frame and cap in central section, and the forward part of the frame and associated parts also in central section; Figs. 1 1 are details of the magazine and .clipf'Fig. 2 is a side eleva- .tion of the breech-block and piston-rod showing the forward end of the breech-block in central section and the shell extractors in elevation; Fig. 3 is a plan view of the breech-block, looking up at its underside,

showing the drive-rod in cross-section, and showing a broken'central sectlon at therein Specification of Letters Patent. P t t Q 10, 1911 Application filed February 1 1, 1904. Serial No. 193,063.

end of the breech-block; Fig. 4 is a central sectional view of the rear end of the breechblock'and associated parts; Fig. 5 is a crosssectional view of the handle part of the frame showing the firing dial and associated parts; Fig. (Sis a rearend elevation of the gun; and Fig. 6 details of the cartridge feed-finger'moi'inting; Fig. 7 is a rear ele\;ation of the cartridg'e feeding fingers; Fig. 8 is a cross-section of the"cartridgefeeding device; Fig. 9 is a side elevation; and Fig. 10 a front end elevation of the breech-block' and associated p'arts; 'Fig. 11 is a central longitudinalsection of the breechblock and associated parts, on the line 11-11,

Fig. 10, and showing the shell extractors in elevation; Fig. 12 is' a'diagramrnatic' view of the cam inthebreechtbck, show-ing'in section the arm on thepiston'cooper'ating with said cam; Fig. 13' is" a 'broken sectional de- .breech-block, showing the cartrid e-ejector in elevation; Fig. 15 is a longitu inal sectional view of the cartridge feeding devices, with parts thereof and the piston-rod in elevation; Fig. 16 is aside elevation of the plate carrying the cartridge-feed devices, which latter are shown in dotten lines; Fig. 17 is a central sectional view of the cylinder head and gas-controlling devices; and Fig. 18 is an end elevation of the same. Fig. 19 is a broken side elevation showing the manner of removably connecting the gas tube or chamber to the barrel; and Fig. 20 is a. front elevation of Fig. 19.

In the drawings, 1 is the gun-frame and 2 is the barrel secured within the forward end of the gun frame by screw-threads 3 en a in corres ondinthreads in the b D b frame- The breech-end of the barrel is cift out or chambered, as at 4, and the interior of this chamber is 'provided with interrupted screw-threads 5 forthe engagement of corresponding screw-threads on the breech-block, as will be hereinafter described. The gun-frame is provided with a longitudinal cylindrical channel (5, extending from end to end thereof in line with the barrel, and a second longitudinal cylindrical channel 7 underneath and parallel with the channel 6. The forward end of the channel 7 is in alinement with and is connected to the tube 8 within which is-located the spring 9 which serves to drive the gas-piston forside of the frame and has its forward nose thrown inward by a spring 12, as shown in Fig. 1, so as to prevent the sleeve from moving rearward under the influence of the spring 9, unless the latch 11 is withdrawn. The rear end of the frame is closed by a cap 13, preferably secured to the end of the frame by interrupted screw-threads 14, the form of the cap being such that when it is imposition it closes the ends of both of the cylindrical channels 6 and 7. The cap 13 has formed therein a dash-pot 15 in alinement with the reciprocatory movement of the breech block, and this dash-pot serves as a buffer and a means 'of controlling the reciprocations of the breechblock, as will be hereinafter more fully described. This cap has also formed thereon flanges 16 which may be engaged by any suitable tool, as, for

example, the shoulder bar, to operate the cap to unscrew it to release itfrom the frame. Between the cylindrical channels 6 and 7 is a slot 8 extending from the rear of the frame. to a point considerably in advance of the rear end of the barrel, this slot being for the purpose of permitting the arm on the iston rod, hereinafter referred to, to pro3ect up into the cylindrical channel 6 and engage the breech block for operating the same. The under side of the frame is suitably slotted for the purpose of permitting the play of the sear and trigger mechanism, and the frame is provided with a handle part 17 which is suitably slotted and reamed out to form a housing for the trigger and the disk which controls the loading and firing action of the Weapon. 7

The breech block 18, best shown in Figs. 2, 3 and 4, 9, 10 and 11, is provided with interrupted screw-threads of the usual or any suitable construct-ion, extending from the front thereof preferably to near the rear end of the block, where there is a portion 19 that is free from screw-threads for the purpose of affording a bearing and guiding surface for the block within its cylindrical guide-way 6. This block is chambered out and has on its under side a slot 20, the forward portion 21 of which is parallel with the axis of the block and the rear portion of which is oblique thereto, whereby a cam surface prsurfaces are provided to be en- 'gaged by the arm on the piston rod of the gun for operating the block. The particn r construction of this lot is best shown in lfiigs. 3 and 12. On one side of the slot is provided an unbroken cam, surface 22 which is engaged by a corresponding cam surface on the arm 23 of the piston rod in the act of opening the breech. The opposite part of the cam p rtion is provided with a cam surface 24 substantially parallel with the cam surface 22 and a cam surface 25, formed at an angle to the cam 24. On the arm 23 of the piston rod there are formed cam.

surfaces 26 and 27 for engagement with the cam surfaces 24 and 25, as will be hereinafter more fully described. The forward end of the breech block is bored out, as at- 28, for the passage of the firing pin and is mortised, as at 29, to afford seats for the extractors 30. These extractors are-similar in construction and are provided with the usual hook or claw for engaging the flange of the cartridge, and at the rear end'with an arm entering somewhat freely into the' mortise 29. Located in a suitable seat formed in the body of the breech block, is a. spring-pressed pin 31 whose spring acts to force the pin against the extractor and keep the same normally rocked forward in position to engage the flange of the eartridge, the extractor rocking about a pin 32. This pin 32 is seated in a hole formed partly in the extractor and partly in the body of the breech block. The extractor moreover is rovided with a suitable flange or tlnunbhold 33, and by rasping the extractor by said thumb-hold zsee Fig. 13) and forcing the same back against the spring-pressed pin 31, the extractor can be freed from the retaining pivot pin 32 and readily removed, the pin 31 being retained in its position by reason of the fact that the forward coil of its spring is small enough to grip and frictionally retain its grip upon the pin, while the rearward coil of the spring is slightly larger than its seat in the block so as to secure frictional contact of the spring with the seat.

'Iherearward rhainbered-out portion of the breech block has a longitudinal slot 34 cut through its wall, and within this slot is mounted the ejector the form of a bar having an angular lug 3G turned to engage a shoulder 37 formed in the slot 34, the ejector being normally held in position with the lug 36 engaging the shoulder 37 by means of'the spring 38 bearing upon the rear end of the ejector. The ejector is also provided with a cam shoulder 39 and on its inner edge there are two lugs 40 which engage the inner surface of the walls of the breech block, as shown in Fig. 14. In assembling the ejector the lugs 40 are placed in position to register with grooves 41, formed in the side of the slot 34, and after the lugs 40 have passed through the grooves 41 the ejector is advanced to the position shown in Figs. 9 and 14, and retained in its forward position bythe action engagement with the shoulder 37.

This ejector is in block, and the ejection of the Fig. 11 two springs 43 and 44 are shown, 4-4

being the lighter spring and receiving and resisting the backward movement. of the piston plate 42 before it comes in contact with the 3 ring 43. For the purpose of affording an a utment for the springs, and also for the purpose of securing a piston packing to the rear end of the breech block, there is formed on the interior of the breech block'an annular screw-threaded h'oulder, which is here shown in the form 0 a ring 45 againstwhich the s ring 43 reacts. The shoulder formed by his ring 45 might be otherwise formed, but the construction wherein the ring 45 is employed greatly facilitates the rapid .and cheap machining of the parts. The interior. of the ring 45 is screwthreaded, as above mentioned, and the plug 46 is screw-threaded therein so as to confine between its mushroom-shaped head and the rear end of-- the breech block a packing 47 of fiber, or other suitable material, the diameter of which is such as to cause itto fit snugly in the buffer cylinder 15 formed in the cap 13 at the rear ot the gun-frame. The plate42 is provided with a central opening or perforation 42" -and the screw-plug 46 has a like central opening or perforation 46, so that a restricted air passage is formed through the rearward part of the breech block for the purpose hereinafter to be described. The piston plate is prevented from moving too far forward under the action of the springs by an annular shoulder 4b, Fig. 1.1, formed on the interior of the block. block has also formed thereon a radial lug or rib 49 (Fig. 9)which travels in a suitable groove 49 formed on the interior wall of the cylindrical chamber 6 of the gun-frame, thereby preventing the brrech block from turning, except when itis in position within the breech of the barrel, thus timing and controlling the locking and unlocking action of the bolt.

The operation of the breech mechanism, including the opening and closing of the breech, the placing of the cartridges in the receiver or chamber 6- infront of the breech empty shell, are all performed by power from. the gases of nearthe muzzle. oinnigid with the piston extends rearward throughwthe tube 8 and into the cylindrical ,chamber '7 where it has rigidly secured thereto the arm 23 shown in Figs. 2, 12 and The a gas 'driven piston 135,

which chamber is 15. This piston rod 51 is surrounded by the coiled spring 9, and passes through the sleeve 10 (Fig. 1), and is provided with a bottom rib 5E2qvhich. snugly fits in a cut-out channel 53 (see Figs. 5 and 6) in the bottom of the chamber 7, thereby serving to steady and guide the reciprocating movements of the piston rod. This piston rod "or drive rod has also formed thereon sear notches 54 and 55 for cooperation with the sear to control the loading. and firing action of the weapon. The firing pin, if desired, might be a loose pin mounted in the breech block,

pin 56 rigidly secured to the arm 23in position to enter the bored-out firing pin openbut as here shown it is in the form of a ing 28 in the breech block. Preferably the 1 pin 56 is removably attached to the arm 23,. The piston rod is also provided atone side, aiid preferably its right-hand side, with a cam, preferably in the form of a cam groove 57, extending forward and downward from its rear end for the purpose of operatively engaging the partsgto effect theplacing of, the cartridges within the receiver as. will be hereinafter described.

The gas-driven piston 'is'located in a gas chamber 59 at the forward end of the gun, preferably supported upon the gun-barrel by means. of any suitable bracket. Communication is established between the bore of the gun and the gas chamber 59.by an opening or openings leading from the gun bore to said chamber, in which chamber provision is .made'for controlling the gas pressure in the chamber. The means for effecting this control are shown in Figs. 17 and 18. The forward end of the gas chamber 59 is closed by ascrew-plug 60 inserted therein, through which plug openings or ports 61 are formed,'and all of these openings or ports are controlled by a valve 62 held yieldingly to its seat by a spring. 63 reacting between the valve and the head of a mushroom-shaped screw-64, secured in the central portion of the screw-cap or plug (30, as will be clearly understoodfrom an inspection of Fig. 17. Preferably the hub or central portion of the cap 60 projects outward slightly, so as to form a. guide for the valve 62 and is, or may be, polygonal in form in order to more effectively perform its guiding functions, as is shown in dotted lines in Fig. 18, where 65 indicates the polygonal guide for the valve 62.

The tension of the-spring '63 holding the ValVQ'GQ to its ,seat is determined by the screw 64. \Vhen the gun is fired and the gases enter .-'chamber 59, if the pressure is above the desired amount, the gases entering port 61 raise the valves 62 against the tension of its spring and escape until the pressurev injthechamber 59 is reduced to the desir d point, when the valve promptly closes. This construction,' not only e eetively controls the pressure of the gas in the chamber 59, but is one which is readily removed in order that the chamber may be inspected and cleaned.

The gun is provided with a substantially vertical magazine 66 placed to one side of the gun frame, preferably the right-hand side as shown in Fig. 6, the magazine being prodded with grooves or guide-ways 67 as shown in dotted lines in Fig. 6, for engagement with the flanges of the cartridge or cartridge clips as the case may be. Adjacent to the bottom of the magazine there is an opening formed in the side of the cylindrical chamber or receiver (3, and a table 68, shown in dotted lines in Fig. 6, is formed in the bottom of t1": magazine 66 to receive the lowermost cartridge. The outer wall of the magazine at its dower part is composed of the flanged plate 69 (see Figs. 6, 8, 15 and 16). This plate is held in position against the flanges in the wall of the magazine by springs 70 (Figs. 6 and 8) which react between the gun frame and socket bearings 71; (Fig. 15) in the plate to hold it'pressed outward firmly against the retaining flanges 72, 73, of the magazine.

Referring now to Figs. 15 and 16, this plate 69 has formed on its interior three pairs of brackets 74, 75 and 76, which are her-ed out in alinement to form the bearings fdr the rock shaft 78, which shaft has akeyway 79 (Fig. 8) extending along its length.

Feed levers 80, 80, are mounted on the rockshaft 79 between the respective pairs of bearing brackets 74 and 75, and anoperating arm r lever 81 (Fig. 8) is mounted on the rock-shaft 7S bet-ween the brackets.76. The feed levers 80, 80, and the arm or lever 81 are all provided with a key-way, as 82, (Fig. 8) and a key 83 enters the key-way 79 on the shaft and the ways 82 in the arms and lever 81, thereby effectively securing the said parts to the shaft and compelling them to turn therewith and yet permitting the ready disassemblage of all the parts by merely removing the key 83. The rock-shaft 78 is normally held in the positions shown in Figs. 6 and 8, z'. e., with the feed levers 80 in their outermost. position, by the action of a coiled spring 8% (Fig. 15) one end of which is secured to a collar 85 attached to the rock-shaft 78 by a set-screw 86, the other end of' the spring being secured to the bracket plate (39 at 87, so that the shaft is rocked in one direction against the tension of the spring 84, and is by the spring returned to its normal posit-ion when freed from the acti..n of the drive rod, as will be hereinafter explained.

For the purpose of holding the bottom cartridge in the magazine in place upon the table 68, until such time as itis to be fed into the receiver, and-furthermore, for the purpose of steadying the feeding action so that the cartridge will be accurately thrown to its position in the receiven by the feed levers 80, the cartridge feed fingers 88 are employed, which bear yieldingly upon the cartridge while it rests upon the table (38 and maintain their yielding bearing upon the cartridge during the action of the cartridge feed levers 80. These cartridge-feed fingers may be placed on either side of the magazine without materially departing from the spirit of the invention, and as here shown are located upon the, left-hand side'thereof. They have both an oscillating and a reciprocating action 'which is secured by pivotingthe fingers 88 to a shank 89 (Fig. 7)., a spring 90 engaging the two parts so as to normally hold the feed-finger 88 in the position shown in Fig. 7. This shank 89 enters a channel 91, removably mounted in the side walls of the magazine (see Figs. 6, 6 and is downwardly pressed by a spring 92, the normal position of the parts being as clearlyshown in Fig. 6. lVhen the cartridge-feed levers 8O advance from right to left to throw the cartridge into the gun, the cartridgefeed fingers 88' bear upon the surface of the cartridge, as shown in Fig. 6, but swing upon their pivot pins and at the same time slightly rise so as to allow the cartridge topass under the lower end of the feed finger. It will be readily perceived that this operation holds the cartridge at all times, firmly but yieldingly against the table and the cartridgefeed levers 80, and prevents any overthrow or nnsplacement of the cartrldge whlch might cause jamming or other inaccuracies in the loading action.

groove 57 upon the rear end of the piston rod, the lever entering the rear end of said groove when the breech block has been drawn sufliciently to the rear to permit the cartridge to enter between the forward end of the breech block and the rear end of the barrel, when the further rearward movement of the piston rod serves to depress the rear end of the lever 81, thereby rocking the shaftand throwing the feed-levers 80 inward and carrying with them the cartridge, as will be readily understood from an inspection of Figs. 6 and 8. As soon as the end of the lever 81 has reached the point 93 in the slot 57 (see Fig. 2),- the spring 84: on the rock-shaft acts to return the shaft to its normal position, the end of the lever 81 traveling in the part 94: of the groove in the drive-rod, as shown in Fig. 2.

For the purpose of drawing the piston rod rearward either to open the breach or disassemble the parts, a sliding bar 95 (Fig. 6) is mounted in a slide-way in the frame and has a handle 96 secured thereto, as well lic- registers with a slot 99 in the slide-way when the handle is raised, at which time the lug 97 lies in front. of a correspondinglug 100 secured to the piston rod 51, as is clearly 5 shown in Fig. 6. By grasping the handle 96, raising it until the shank registers with slot 99 and drawing the same-rearward, the ])lSt()11-lOd may be withdrawn to the rear for the purpose of opening the breech or, if the cap 13 has been removed from the gunframe, it maybewithdrawn rearward so as to bring the breech-block out of the chainher 6, when it can be separated from the piston rod. Before it is possible, however, 15 t0 thus withdraw the piston rod so far to the rear, it is necessary to operate the catch 11 so as to free the sleeve 10 which forms the abutment for the spring 9. This being done all of the parts, piston-rod, sleeve, zosprin g and piston,-as. well as the breechblock, can be entirely withdrawn. It will be readily appreciated that the only tool necessary for thusdisassembling the parts will be such'a tool as would "fit in between the flanges 16 upon the cap '13, to give it a partial turn in order to disengage'the inter-' rupted screw-threads thereon, and as has been hereinbefore stated, the shank of the shoulder bar would form an effective tool for this purpose. Moreover, for disassembling the parts connected with the feeding of the cartridges into the receiver, it will only be necessary to' push in the lower part of the bracket plate 69 against the tension of the springs 70, therebytreeingthe flanges on the plate from the upper flanges 72 upon the magazine wall, when the entire bracket plate can be'withdrawn from the gun.- A

very efiicient means for thus pushing the 40 bracket plate in is secured by forming flanges 101 (Figs. 1. (i and 8) upon the bracket plate. which flanges are adapted to receivethe shank of the shoulder bar which may then be utilized for pushing the lower part of the bracket plate inward-as above sug gestcd. The bracket plate having been re-' moved from the magazine, it is only ncccs;

sary to push out the key 83, whcn all it-the parts, including the feed lever 80, operating lever 81, and the. rock shaft 78, can he re moved.

From the foregoing, it will he appreciated that tlic entire disasseii'ihliug of the gun can be readily atwoniplished without the use 55 of any special tools, and can be as .rcadily and quickly asscniliiled without tools.

Referring now to the sear a iid trigger deviccsfand the means for controlling the:

' and then lip ofi into engagement with the same, as shown-in Figs. 1 and :'1,the scar I02 is pivotally mounted in a lower extension of the t'rauic. living pi'cfcrablv pivoted to a I hank pin 103 which has bearing upon a spring 04. and the sear itself being nor mally held in an elevated position by a scarspring :05. The scar itself is provided with i pulled. v

a sear-shoulder 106. for engagement with the sear-notches 54 and 55 upon the piston or drive-rod, 'and hasat its rear end a notch 10?. The trigger 108 is pivoted at 105), haviiig an oblong pivot bearing 110, as shown by dotted lines in Fig. 1', and is iioriually held with its sear-engaging nose in elevated position by the trigger-spring 111'. When Figs. 1 and Thisdial is secured to a pin 113., rigid with ahandle 114,-and a spring 115 reacts between the dial and a' faceplate llt ClQSingthe recess forming the housing for the dial. The handle 114 has formed thereon a lug- 117 (Fig; 5)

for yie-ldinglv engaging recesses or notches 1 18, 119 and l20,.all='of,which are clearly shown in Fig. 1,'and.an'other similar notch which does not appearin Fig.".-1,-sinc'e itis covered by the handle 114. The dial'plate v is provided. with shoulders 121, 122,123 and 124, which shouldersact to limit :the movement of. the trigger by reason ofv the engagement of a. lug 125mm the t-riggcrand which plays in a slot 126 (Fig.5) so, as to come in contact with thelfiring dial as'the trigger By turning the dial to the position shown in Fig. 1, the Sl1011ld01 12 3 on the dial is' brought into position. so as to allow the trigger tolbe pulled far enough to 'entirely depress the sear below both of the scar notches on the, piston-rod 51, and the weapon-automatically loads and "fires as long as car tridgcsarc fed thereto from the inaga'lzinc, the operator ii ierely holding the trigger with the lug 125 firmly against the shoulder 123. By adjustnient'to thesother positions iii'dicatcdby the notches 118. 11$) and 120, the trigger may lmeithcr locked so that it can- 'Jltit be tircd at, :1ll adjustcd so that the sear will engage at each discharge with the scar notch 54 to hold the hi-i-cclropcn for single loading or with the scar iiotch for I magazine loading but single firing, the form of the various shoulders being such as to either permit the trigger when pulled to rotain the sea r entirely out ot-thc line of both ni'itches. as when it iuigagcs the upper surface otthe 5011110! to permit it to first engage the upper surface, withdraw the sear from engagement with the sear notch 54:,

notch 107 which will permit the sear to rise into cngagciucnt with ,the notch 55,-when a Furthi-r pull will discharge the gun. l Referringto Figs. 19 and 20, the gas tube 8, the rca r portion of which is shown in Fig. 1 attached to the gun frame, is supported at its forward end upon the muzzle of the bartube or chamber. This portion of the tube constitutes a cylinder 59 which, as before 10 stated, is in direct communication with the bore of the barrel through suitable channels or passages shown in dotted lines at 134. Preferably there is a plurality of suchchannels as shown, though manifestly a single channel of suitableshape and size might be employed, if desired. In Figs. 19 and 20 the end closure or cap of the gas tube, as shown in Fig. 17, is removed. This construction provides for the ready assemblage and dis- 20 assemblage of the tube at the muzzle end of the barrel.

The operation of the gun will be readily understood. The gases entering the gas chamber 59 through the openings 134, drive the piston 135 rearward and with it the drive rod or operating slide 51. In its rearward movement the arm 23 on said slide first travels in the-portion 20' of the actuating slot in the breech block and then impinges 80 upon the cam" 22 which turns the breech block so as to unlock it, and on its further rearward movement the arm 23 strikes the spring-pressed plate or cap 42 covering the perforations 42" therethrough. The spring 44 takes up the first part of the blow of the slide and is subsequently reinforced by the spring 43.- The breech block is then driven rearward and just before it reaches its full open position, the piston on the end of the 40 breech block enters the dash-pot 15 in the cap of the chamber 6 and thus serves to relieve the shock and slow down the action of the breech block by reason of the air confined in the dash-pot, the air very slowly escaping either past the piston or through the perforation 46, and the perforation 42 in the spring plate. As soon as the breech block has come to rest, the springs 43 and 44 act to slowly advance the arm 23 of the slide until the cam face 26 on said slide is brought into contact with the portion 25 of the double cam on the right-hand side of the slot, in which position, assuming the firing 3k 112 to be set for single'load and firing, tie notch 54 on thedrivc-rod is engaged by the scar and the parts are held in this position. A pull upon the trigger releases the sear from the notch 54 and permits the advance of the slide, and with it the arm 6 23, under the influence of the spring 9. During the rearward travel of the bleach block, the lug 49 engages and travels in the groove 49", Fig. 1, so as to prevent the rotation of the breech block during its rearward travel, and

when the drive rod is released from the sear the engagement of the cam 25 with the cam 26 forces the breech block forward until the lug 49 is released from the groove 49 which only occurs whenthe breech block has entered the breech chamber of the barrel in position to be turned to cause its interrupted threads to turn and lock with the corresponding threads in the breech of the barrel. The advance of the arm 23 at the instant the sear engages the notch 54 relieves the pressure of said arm on the spring plate 42, and uncovers the port 42 therein so that air is enabled to enter through said restricted port and the re stricted port 46 into the dash-pot, the spring plate 42 being slightly advanced in front of the spring 43 by the lighter spring 44. \Vhen the slide is relieved from the restraining action of the sear, the arm 23 advances, acting upon the cam 26 and the breech block is prevented from turning by the engagement of the lug 49 on the breech block with a groove 4'9 in the chamber .6. The block having been fully entered in the breech of the barrel, the action of the cam 26 on the cam face 25, commences the turning action of the block to lock it and the cam 27 on the arm 23 then engages the cam 24 and completes the locking action. Owing to the difference in pitch between the earns 24 and 25 the tendency of the breech-block to turn while the lug 49 is in groove 49 is loss while cams 26 and 25 are engaged, than while cams 2-7 and 24 are acting. The sudden bringing forward of the breech block and the slide under the influence of the spring 9, when theslide is released from the engagement of the sear, is slowed down and shock prevented by the engagement of the piston on the rear of the block with the dash-pot, the restricted passages 42 and 4G permitting air to enter, which prevents too great a suction, but being in small enough quantity to cause a slight retardation 'of the closing action. In the act of opening the breech, the shoulder 39 upon the ejector impinges upon the corresponding shoulder 39 (Fig. 6) in the receiver and suddenly throwsthc ejector in ward, thereby forcing the cartridge out through the opening 39 in the receiver, indicated by the dotted lines at the upper lefthand part of Fig. (i, this opening 39 being the usual and well-known form of cartridge ejector opening. In the opening movement of the rm-iprocating slide, 51, just after the breech block has been opened the full length of a cartridge. the arm 81 (Fig. 8) of the cartridge feeding device enters the cam gro'ove 5'7 at the rear end of the slide. thereby depressing the arm and advancing the feed levers 30 toward the receiver. carrying with it the cartridge resting upon the table 68, the movement of the cartridge, however, being steadied by the action of the cartridge food lovers 88, as previously described. "-he action of the cartridge is, furthermore,

steadied-and its seat upon the cartridge feed levers 80. is rendered more firm and secure by reason of brackets 80 projecting laterally from the side .of the feed levers, as shown in full lines in Fig'lS and in dotted lines'in Fig. (3, said brackets having an upper'surface curved to conform to the outline of the cartridge. The tension of the-gasesjin the I gas cylinder 59 and the violence with which ill); impel the piston audits attached slide rearward, is .dete'rmined by the'adjustment of the screw 64: bearing upon the 5 ring 3,

- which controls the valve 62 over t e ports shaft engaging grooves in tlrelevers, or the,

61 at the forward end of the gas chamber.

- It will be observed that the entire structure of the'gun .is very simple in character, and one readily assembled and disassembled without the-employment of tools. By de-' pressing the spring-catch 11 and removing the cap 13, the piston and slide, the spring 9 and the breech block can all be readily and,

entirely withdrawn from the gun. It has heretofore been explained how, by simply pressing in the bracket plate 69 carrying the cartridge feed devices, it can be readily removed from the. gun, carrying with it all of I block, a piston thereon having an 0.1! port extending there'through, a chamber-within the elements which operate to' feed the "cartridges,'-imd by the removal of the key which connects the plate, the'rock-shaft and the levers thef eon," the same may be all'entirely separated." Itwill be understood that-this key might, if desired, be integral with /the levers mounted on the shaft might have keys formed for engagm'ent with a longitudinal groove in the shaft. Moreover, it will be understood that tho tcnsion of the spring 84' on said shaft, can be adjusted by merely loosening the set-screw 86 and turning the.

collar 85 around the shaft in either direction, suitable depressions, if desired, being formed in the'shat't to afford a secure hold on the set-screw. r

. Referring to the extractors,-it has already been explained how, by reason of their con struct-ion and method ofmounting, they can be readily disassembled by simply pushing them slightlybackagainst the pins 31, and thereby freeing them. from the pivot pins 32, after which they can'be lifted out of theextractor seats. The ejector may also be withdrawn from its seat by simply pressing it rearward against the tension of the spring 38 uut' the lugs 40 on the ejector register with the grooves 41 in the side faces of the slot 34, when the ejector can be elevated out of the slot 34. The piston and butter spring mechanism at the rear end of the' breech block can be entirely disassembled by unthc screw-plug 46 and the ring 45, when :1 moved. Usually the cartridges to beinsertcd in the ma azine'are contained in a cartridge clip 140 fig. 1") of any desired or suitable construction and for the purpose of retain actuated by the gases of disc of these parts can be readily reis inserted into the magazine, said clip'is provided with a spring-pressed 'retainin catch 141. This retaining catch is rovide with a lug, or preferably a pair of age 142,

while the. magazine. has a cam surface 143 near its lower rearend' so formed and p0sitioned as to enga e the cam'lugs 142 on the catch 141 and wit draw said ca'tchfrom-um derneath the cartridges as the clip is forced into the magazine. The bottom portion. of this cam surface is in the form of a rounded undercut 11 144 which actsto. engage the lo 142 an thereby hold-the clip in the magazine, the spring of the catch .141 yielding sufficiently to free the clipwhen force is applied to withdraw it from the magazine.

Vhat is claimed is: a

1. In a gun, the combinationof a breech block, a piston thereon having an air port extending therethrough, a chamber within which the said block reci'procates, and a dash- 0t in said chamber in position to be entered y said piston on its terminal rearward movement. 2. In a: gumthe combination of a breech block and controlling the passage of air through said port, and a dash-pot in said chamber in position to be entered by said piston on its terminal rearwardfmovement. 4. In a gun, the combination of a breech block, a piston thereon having an air port extending therethrough, a chamber within which the breech block reciprocates, a discharge-actuated slide imparting reciprocating movements to the block and controlling 'the passage of air th ough said port, and a.

dash-pot in said chamber in position to be entered by sald piston on its terminal rearward movement.

5. In a gun, the lcombination of a breech block, a piston thereon having an air port extending therethrough, a chamber within which the breech block reciprocates, a slide arge impartin reciprocating movements to the block an controlling the passage ofair through said ort and a dashwt in said chamber in osition to be entered by said piston on its terminal rearward movement.

6. In a gun, the combination of a recipro eating breech block, a breech-block-operating 13L slide, and a pair of buffer springs inte'rpose between the block and slide, first one and then both of said springs acting to cushion the blow of the slide upon the block.

7. In a gun, the combination of a reciprocating breech-block, a discharge-actuated breech-block-operating slide, and a pair of buffer springs interposed between the block andfslide, first one and then both of-said springs acting to cushion the blow of the slide upon the block.

piston" on the rear end of-the block, and a breech-bloek-operating I slide engaging the said piston plate or cap and controlling the port therein.

t 9. In a gun, the combination of a receiver chamber, a dash-pot in connection therewith,

a breech-block forming a piston for engagement with saiddash-pot, an air-port leading irom said dash-pot, and a. breech-blockoperating elementcontrolling said port.

10, In a gun,-the cornbination of a receiver chamber, --'a dash pot therein, breech-block forming a piston-for engagement with said dash-pot, a spring-pressed plate in front of the piston and having-a port' for the passage of air into and out-of said dash-pot, and a breech-block -1 operating element controlling said ports,

'ILFIna gun, a receiver-chamber and a dash-pot in line therewith, a breech-block forming a piston movable in said chamber and dash-pot, a. spring-controlled plate car- .ried by said breech-block, a port or opening through saidpiston and plate and breechblock-operating means opening and closing said port. V 12. In a gun, a'brehch bl'ock having an ejector seat in the form ofa slot through the walls of the block, an ejector seated said slot. andhaving'lugs engaging the intcrior-j surface of the block, and grooves forum-:1 in one \\1Llli0f the slot and arranged to "register withlsaid lugs when the e ector slightly shifted from normal position,

in position fangLi-cmoved therefrom.

; l3. Ina gun, abrecch-bloclg having ail ejector scat inthe form of a slot through the wall of the block with grooves extending acmss one face of the slot, a n ejector mountwhereby the ejector may be .readily'placcd ydifl-iii" said slot and having lugs spaced to if "register with sald grooves when the e ector is'slightly to th rear of its normal position,

a hearing point on the breech-block around which the ejector normally turns. and a spring-holding the ejector against said point.

I4. In a gun, a breech-block having a cartrldge-ejector seat in the form of a slot through the walls of the block, said slot having a groove in one of its faces, and an exterior recess at oneside of the groove, and,

an ejector seated in said slot and having a lug fitting in said recess so as to have 1on gitudinal play therein and also having a side lug registering with said groove when'g -i.

the ejector is in its rearward p .ition.

15. In a gun, a breech-block ht ving a carlugs registering with said grooves only'when the ejectbr is shifted from its-normal posi-- .75 tridge-ejeetor seat in the "form of a "slot tion, a cam on. theiejectorj-and-a shoulder in the receiver for operating the ejector.

17 In a, air, a breech-block having an in-. terior chain 'er, a longitudinal slot through the walls of the block into said chamber and having a groove formed in one of its faces and a 'recess'on the, side of said slot of greater widththjansiiid groove, an ejector havingtwo lugs one of which has longitudin l. movement in said recess and the other of which normally engages the inner Wall of the block, but registers with said groove when the other lug is at the rear of its recess. v 1

d8. In a gun, a chambered breech-block having a slot in its wall, and an ejector, seated in said slot and having. a lug at one end engaging the exterior of the block and having another lug engaging the inter or of the block.

19. In a gun, a chambcred'breech-block having a slot in its walhan ejector seated in said slot and having a lug at its rear end engaging a shoulder on the outer part of the block and another lug engaging the interior wall of the block, and a-spring holding the first-mentioned .lug yieldingly against said shoulder.

"20. In agim, a receiver, a reciprocating and rotating chambered breech-block having a longitudinal slot in its wall, an ejector seated in'said slot and having a. lug at one end engaging the exterior of the block and another lug engaging the interior of the block, a cam onthe ejector and a. shoulder on the receiver in the path of. the cam on the ejector, and a gas-driven piston operatively engaging the breech-block.

- Cit breeclrblock, a piston on the rear end of the block, a butter or cushion carried by the block,a receiver having a dash-pot in line with the breechblock, and a gas -driven. slide operatively engaging said block and also engaging said buffer or cushion,

In a gun, a gas cylinder connnunicating with the gun bore, a piston in said cylinder, a removable closure for the front end of said cylinder, ports through said closure and an automatic relief valve controlling said ports.

23. In a gun, a gas cylinder communicating with the gun bore, a piston in said cylinder, a removable closure for the front end of said cylinder, ports through said closure, a valve controlling said ports,-a spring hearing on said valve and a screw regulating the tension of said sprin 24; In a gun, a barrel, a gas cylinder commun-icating with the gun bore, vent ports to the atmosphere, a piston in said cylinder, and a valve coiitrolling said ports independent of said piston. 7

'25..In a gun, a gas cylinder, a piston therein, a port connecting the barrel with said gas cylinder on the working side of said piston, a vent port or ports for said gas cylinder leading fronr the working side of the piston to the atmosphere, and a springpressed valve controlling said port or ports. 26. In a gun, a tgas cylinder communicating with the gunbore, vent ports to 'said' cylinder, a spring-pressed valve controlling said ports, and a. SCI'QWfldJIlStlD thetension of said spring.

27. In a gun, the combination of a breech block, agasdriven slide operatively engagin'g said block, chambers in which said block and slide reciprocate, a collar surrounding saiil slide within one of said chambers, a catch restraining said collar against rearward movement, and a spring reacting between said collar and a. piston on the slide.

In a gun, a ln.-c.ccl1-block, a gas-driven piston operatively connected thereto, a chamber within which said piston works, and automatic means limiting the gas pressure within said chamber.

'21). In a. gun, a piston actuated by the gases of discharge, and automatic means limiting the gas pressure on the piston to a predetermined degree.

3-0. In a gun, a gas'chamber communicating with the bore, a vent port or vent .ports to the atmosphere, a. reciprocating piston in said chamber, and an automatic relief valve independent of said piston controlling said vent pirt or ports.

' 31. In a magazine gun, a cartridge-feed mechanism for inserting the cartridges into the receiver, a removable bracket plate upon which said feed mechanism is lllULllllt-i'i, and

discharge-actuated means operatively connected to said feed mechanism. 32; In a magazine gun, a rock-shaft mounted in a removable bracket plate, cart-ridge-feed levers on said rock-shaft, a discharge actuated slide and operative connections-between said slide and rock-shaft.

In a magazine gun, transversely-operating cartridge-feed mechanism and a removable plate on the side of the magazine supporting said feed mechanism.

34. In a magazine gun, a bracket plate having flanged engagement with the walls of the magazine, cartridge-feed mechanism supported on said plate, and yieldiir devices holding said plate in engagement with the flanges on the magazine.

35. In a magazine gun, a removable bracketplate forming the lower wall of the magazine, and cartridge-feed mechanism removablysecuredto said bracket plate.

36. In a magazine gun, a bracket,- plate yieldingly held in flanged engagement, with the magazine, bearing'brackets on said plate, an operating lever and a. cartridge-feed lever held between said bracket bearings, and a rock-shaft passing through said levers and brackets and keyed to" saidlevers.

37. In a magazinegun, a removable bracket plate, bracket bearings on the inte -ri'or of said plate, a cartridge-feed lever and an operating lever located between said bracket bearings," a rock-shaft passing through said bearings and said levers and a key securing said levers and rock-shaft together.

38. In a magazine gun, a removable bracket plate, a plurality of hearing I) 'ackcts on the face of said plate, a cartridge-teed lever and operating lever located between said bracket bearings, a. rock-shaft keyed to said levers and passing through said bearings, and a gas operated slide engaging sail ope 'ating lever.

39. In a magazine gun, an oscillating and reciprocating cartridgeteed finger and means holding the same in yielding contact,

with the cartridge.

40. In a magazine gun, a cartridge-teed finger, a shank to which said linger pivotally .united, a guideway within which said shank is located, and a spring pressingupon said shank, whereby the cartridgefeed tin gcr is enabled to both oscillate and reciprocate under the feeding action of the cartridge. I

41. In a nmgazine gun, a spring-pressed rcci 'ii'ocating and oscillating cartridge-feed finger removably mounted'in the magazine.

42. In a gas-actuated automatic gun, the combination of a breech block, a gas-driven piston opcrativcly engaging the same, a spring for moving the piston forward and an adjustable abutment for the rear end of said spring whereby it may be put under tension or the tension thereof be released at wi 1. c

- &3. In a gas-actuated automatic gun, the combination of a reciprocating piston rod and a breech block operatively connected thereto, with a spring for impelling the piston rod forward, a sleeve surrounding the piston rod and forming an abutment for the c 10 rear of said spring, and means for adjusting said sleeve upon the rod to place the springspecification in the presence of two subscrib- 15 ing witnesses.

' SAMUEL N. MOCLEAN. \Vitnesses:

S. T. CAMERON,

TM. B. HERKANE.

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