US2466577A

US2466577A - Bolt mechanism for guns

Info

Publication number: US2466577A
Application number: US566806A
Authority: US
Inventors: Corte Alfred
Original assignee: Lockheed Aircraft Corp
Current assignee: Lockheed Corp
Priority date: 1944-12-06
Filing date: 1944-12-06
Publication date: 1949-04-05
Anticipated expiration: 1966-04-05

Description

April 5, 1949. A. CORTE BOLT MECHANISM FOR GUNS 5 Sheets-Sheet 1 INVENTOR. ALFRED CORTE Filed Dec. 6, 1944 AGENT Apn il 5, 1949. A. CORTE 2,466,577

BOLT MECHANISM FOR GUNS Filed Dec. 6, 1944 I 5 Sheets-Sheet 2 la.w

I I32 I64 f1 I I28 I59 I54 W INVENTOR, 55M 64 ALFRED com;

2o Inn 12 I AGENT 1 April 5, 1949. A. cORTE 2,466,577

BOLT MECHANISM FOR GUNS Filed De -6, 1944 5 Sheets-Sheet 5 8 I l 67 INVENTOR. ALFRED CORTE AGENT April 5, 1949. A. CORTE BOLT MECHANISM FOR GUNS v5 She'ets-Sheet 4 Filed Dec. 6, 1944 E T R C D E R F L A A. CORTE BOLT MECHANISM FOR 'GUNS April 5, 1949.

5 Sheets-Sheet 5 Filed 'Dec. .6, 1944 I INVENT0R. ALFRED CoRTE AGENT Patented Apr. 5, 1949 UNITED STATES PATENT "OFFICE Alfred Corte, Glendale, Calif., assignor to Lookheed Aircraft Corporation, Burbank, Calif.

Application December 6, 1944, Serial No. 566,806

15 Claims. (Cl. 89-459) This invention relates to ordnance,. and relates more particularly to automatic or machine guns. A general object of the invention is to provide a machine gun or cannon mechanism embodying a practical and particularly effective breech block and breech bolt assembly.

The mechanism of the present invention is intended for use in a machine gun wherein a live round is withdrawn from the ammunition belt, then introduced into the cartridge chamber for firing, and following the firing of the round, the empty cartridge case is withdrawn from the chamber and replaced in the ammunition belt. When this sequence is performed in connection with the firing of successive rounds, the ammunition belt is partially emptied and then rebuilt or refilled as it passes through the gun. The reinsertion of the empty cartridge cases in the ammunition belt completely avoids the necessity for providing means to handle the empty cases, and where disintegrating belts are employed, the re-insertion of the empty oases prevents disintegration of the belt so that the continuous belt carrying the empty cases may be readily directed into an appropriate receiver or storage space. If desired, the belt may be re-used Without the necessity of re-assembling its individual links. In order to successively withdraw a round from the belt, fire the round and then replace the empty case in the belt, thegun mechanism requires a plurality of bolts for cooperating with a single breech block, with round extracting means associated with the bolts. The present invention is concerned primarily with the barrel extension and multiple bolt assembly and the associated elements.

It is an object of the invention to provide a barrel extension and multi-bolt combination of the character above referred to that is positive, dependable and rapid in operation.

Another object of the invention is to provide a sturdy, effective means for successiveli' locking the individual bolts in the barrel extension for the firing of the successive rounds.

Another object of the invention is to "rovide a simple, rapid-action means for actuating and releasing. the breech locks. The mechanism em bodies jaws or looks adapted to be simultaneously operated upon the insertionand withdrawal of the bolts, and a positive quick-action rack mechanism for projectingand retracting. the looks.

A further obiectof; thev invention. is to provide a mechanism of. the character referredto embodying a simple latchmeans which serves to positively hold the breech locks-retracted to 2 permit free insertion of the bolts and which further serves to prevent premature release of the breech locks.

It is a further object of the invention to provide an effective extractor mechanism for the breech bolts, which automatically operates to withdraw the live rounds from the ammunition belt and later insert the empty cases into the belt.

A still further object of the invention is to provide a gun mechanism of the character re,- ferred to in which a firing pin device is associated with each individual bolt. and embodies a safety unit for preventing inadvertent and premature actuation of the firing pin.

Other objects and features of the invention will be readily understood from th -following detailed description of a typical preferred form of the invention wherein reference will be made to the accompanying drawings in which:

Figure 1 is an elevation of the rear portion of a gun embodying the invention;

Figure 2 is an elevation of the forward portion of the gun with certain parts broken away to appear in longitudinal cross section; I

Figure 3 is a longitudinal detailed sectional view through the forward portion of the gun receiver showing the internal parts in elevation;

Figure 4 is a fragmentary longitudinal sectional view of a portion of the gun illustrating the ammunition sprocket and its operating mechanism, and showing portions of the barrel and gas cylinder mechanism inelevation;

Figure 5 is a longitudinal sectional View of the rear portion of the gun with the bolt assembly and a portion of the mechanism for turning the same appearing in elevation;

Figure 6 is a stretch-out view of the drum cam for rotating the bolts;

Figure 6A is an enlarged fragmentary sectional view illustrating the cooking mechanism;

Figure 6B is an enlarged fragmentary sectional view of the firing pin safety means;

Figure 7 is a side elevation of the bolt assembly and its associated actuator;

Figure 8 is afront elevation of the bolt assembly taken substantially as indicated by line 38 on Figure 7; v

Figure 9 is a fragmentary longitudinal sectional view of the actuator assembly taken as indicated by line 9-9 on Figure 8.;

Figure 10 is a face elevation of one of the bolts carrying a round and showing the two positions of the extractors,- being a view taken substantially as indicated by line ill-10 on Figure 8-;

Figure 11 is an enlarged transverse sectional view of the actuator taken substantially as indicated byline IIII on Figure '7;

Figure 12 is a longitudinal sectional view of one of the bolt units;

Figure 13 is an enlarged fragmentary longitudinal section taken substantially as indicated by line l3--I3 on Figure 7;

Figure 14 is a front view of one of the bolts;

Figure 15 is an enlarged transverse sectional view of the actuator, taken as indicated by line II5 on Figure 7;

Figure 16 is an enlarged fragmentary sectional view taken as indicated by line IBI6 on Figure Figure 17 is a fragmentary perspective view of a portion of a bolt assembly;

Figure 18 is an enlarged side elevation of the barrel extension assembly;

Figure 19 is an enlarged vertical section taken as indicated by line I9.l9 on Figure 18;

Figure 20 is an end view of the barrel extension assembly taken as indicated by line 28-28 on Figure 18;

Figure 21 is a horizontal sectional view of the rack unit showing the two racks in elevation;

Figure 22 is an enlarged transverse section taken as indicated by line 22-22 on Figure 21;

Figure 23 is a longitudinal detailed sectional view of the barrel extension assembly taken as indicated by line 23-23 on Figure 20;

Figure 24 is a fragmentary view illustrating the breech latch mechanism;

Figure 25 is a horizontal detailed sectional view of the block assembly taken as indicated by line 25-25 on Figure 20;

Figure 26 is a transverse cross section of the sprocket taken as indicated by line 26-26 on Figure 27;

Figur 27 is a side elevation of the sprocket and ammunition belt assembly;

Figure 28 is a vertical detailed sectional view taken as indicated by line 28--28 on Figure 3;

Figure 29 is a fragmentary vertical sectional view taken as indicated by line 29-29 on Figure 2'7; and

Figure 30 is a transverse section of one of the racks and its jaws as indicated by line 3ll-30 on Figure 25.

The features of the present invention may be embodied in ordnance varying considerably in caliber and construction. In the drawings the invention is disclosed in association with a substantially complete gun structure, it being understood that the invention is not to be construed as limited to the particular details illustrated and described below.

The gun illustrated includes a housing or receiver [0, which is a relatively stationary com- .ponent being adapted for support by either a stationary or flexible gun mount. The receiver I0 serves as asupport for the various other elements and contains the principal operating parts. As the present invention is not primarily concerned with the construction of the receiver I0, it will suffice to describe it as an elongate hollow member having generally vertical side walls II, a top Wall having a longitudinally extending partially cylindrical crown I2, a bottom wall I3 presenting a cylindrically concave internal surface, and end walls I4 and I5. The forward portion of the bottom wall I3 has a rectangular downwardly opening magazine frame It for detachably mounting a suitable magazine, not shown. Horizontally spaced guide rods I'I exreceiver H]; see Figures 2 and 4.

tend longitudinally through the receiver ID to carry the bolt assembly for axial movement will be subsequently described. "While I have referred to the receiver Ill as having side walls and top and bottom walls, it is to be understood that the gun may be mounted and employed in any position; for example, it may be supported so that the parallel walls II form the upper and lower walls of the receiver.

The gun barrel I8 extends forwardly f rom the receiver I0 and is supported for axial movement as required during the recoil and counter recoil phases of operation. The forward wall ii of the receiver Ill carries a suitable slide bearing unit I9 cooperating with a splined or grooved .po ion of the barrel I8 to support the barrel for the required limited axial movement. The details of the bearing I9 and its mounting form no part of the present invention. The barrel it extends rearwardly into the receiver It} for association with the extension 53 to be subsequently described. A suitable recoil mechanism is provided for the barrel assembly. This includes a tubular jacket 20 secured to the forward end the receiver II] by screws 2! and extending outwardly in spaced surrounding relation to the barrel l3. The jacket 20 is perforated or slotted for the ready dissipation of heat and its forward end carries a bearing means 22 which assists in support-- ing the barrel I8 for axial movement. A helical recoil spring 23 is arranged in the jacket 2? in surrounding relation to the barrel Ill. The ward end of the spring 23 is engaged by a pull; 24 of the bearing means 22 which travels with the barrel I8 and the rear end of the 23 bears on a ring 25which is stationary on the With this arrangement of parts, the spring 23 is compressed during recoil movement of the barrel is and the energy stored in the spring during recoil serves to move the barrel and associated forwardly for the counter recoil stroke. A flaring muzzle member 26 is provided on the forward end of the barrel [8 and may contain a suitable flash tube, not shown. It is to be understood that the barrel I8 is suitably rifled and may be of any selected construction and caliber.

Certain elements of the gun mechanism are gas operated; that is, they are operated by a portion of the gas pressure built up in the bore of the barrel I8 when the projectile leaves its cartridge case. A gas cylinder 2? extends in parallel relation with the barrel 8. The cylinder 2! travels with the barrel and enters an opening 28 in the forward wall of the receiver I0. A yoke member 29 engages about the barrel I8 and the cylinder 21 to secure the cylinder to the barrel; see Figure 2. The yoke member is attached to the barrel I8 adjacent the bearing means 22. The forward end of the gas cylinder 21 is closed and secured to the barrel I8 by a connecting member 30. Aligned ports 3! and 82 are provided in the forward parts of the barrel [8 and cylinder 21 and are connected by a tubular junction member 33 engaged about the cylinder and secured on the barrel I8 adjacent its muzzle 26. The ports 3| and 32 and the tubular junction member 33 serve to conduct gas pressure from the bore of the barrel lg to the forward portion of the cylinder 21.

A piston 34 is operable in the cylinder 21 and is adapted to be driven rearwardly by the gas pressure conducted to the cylinder from the barrel I8 immediately following the ejection of the projectile from the barrel. The piston 34 is closed aacacvv at-its iorwardaendibutitsanajorportion is tubular. A tubular piston (extension '35 continues rearswardly .from the ilJlStOIl to project from the rear end .of the cylinder :into the receiver 10. ALspring 35 is arranged cinder compress-ion between the closed forward end of the :piston 3'4 and a block .35! rslidably engaged in the :tubular piston extension 35;; :see Figure 4. Pins 38 pass through axial slots in the extension 35 and anchor the block 13-! to the wall of the cylinder 12:1 so that the block forms an zeiiective abutment for thespring. :Upon rearward movement of the piston :34 under the action (of the :gas pressure, the spring .36 is compressed .between the :rearwardly :moring closed end of the piston and .the :block :31. When the gas pressure is relieved, the energyistored in the spring .36 drives :the piston :34 rf'orwardly. The iorwa'rd and rearward movements f the-piston 34 :are utilized to translate .the bolt assembly, :as ibfl subsequently described.

"The gun :mechanism turther includes a'sprock- St 39 arranged in the :iorward portion of the re- :ceiver :lfl to handle the ammunition 'belt ':B as it moves through the gun. The shape and action (of the sprocket 39 \will vary somewhat depending upon :the nature and caliber :of the rounds 1R. Furthermore, the sprocket 39 may .be driven or rotated in various appropriate :manners to effect :an automatic .feed of the ammunition belt 1B. In the construction illustrated, the counter :recoil motion :of :the barrel 18 is employed to intermitstently rotate the sprocket 3.9, and the sprocket zservesito advance the belt '58 in timed relation to the elements of the mechanism.

Thegsprocket SzQ is positioned adjacent themagf azine frame .143, and has :its axis of rotation parallel with the ibarrel. The sprocket "3'9 vis fixed :to its shaft All, and the shaft is carried by suitable bearings AI at the frame :16; see Figure 4. Equally spaced longitudinal grooves 42 are :iormed in the periphery of the sprocket -39 to receive the rounds B, and a circumferential groove 43 is "formedin'thesprocket to receive the links L of the belt B. The axial grooves 42 are of rearwardly in- :c-reasingwdepth to properly receive theprojectiles and theiroases. The particular belt B illustrated .is of the non-disintegrating type comprising gen.- .erallytubular'links L interconnected :by hinges 44; see Eigure29. indicated by broken lines in Fig- .ure 28,'the belt 5 enters the opening of the frame to passes 180 around the sprocket .39, and then outwardly through the frame opening. It will be observed that the belt B enters and leaves {a single side of the gun, thereby greatly simplifying the mounting of the gun and permitting it to be positioned in confined spaces where only :one side is accessible.

The sprocket 39 is rotated substantially 60 during each counter recoil stroke of the barrel [8. The mechanism for producing this intermittent rotation of the sprocket 39 may take various forms and the invention is not primarily concerned with the particular mechanism employed. In the drawings the mechanism for this purpose is illustrated in a more or less diagrammatic manner, and comprises a drum .45 fixed to the forward end of the sprocket shaft 48; seeFigure 4. The drum .45 may be positioned in front of the receiver 40 and may have a suitable casing, not shown. The sprocket rotating mechanism further includes a rod 45 fixed to the above described yoke 29 to move with the barrel Ill. The rod 46 extends rearwardly to enter the forward end of the drum 45. A flange or collar 41 is fixed to the .rod 46 to oper e Wi in the dru Th s oc e drum -45 provided with six equally spaced axial slots 48. correspondingly pitched helical slots "43 are formed in the wall of the drum 45 to'extend between and connect the adjacent axial slots 48. =Pivoted spring urged switches 50 are provided at the junction of the

slots

48 and 49. The switches 58 occur at the rearward ends of the helical slots 49 and are designed to direct forwardly moving objects in the slots 48 into the helical slots 49. Lugs 5| are provided on the flange it] to move in the

slots

48 and 49, it being preferred to provide a log =51 ior 'each axial slot. The lugs .511 are diamond shaped to have pairs of parallel sides operable in both the axial slots 43 and pitched slots 49. Pivoted spring urged switches =52 are provided at the forward ends of the helical slots is to prevent the lugs '51 from moving into the slots 49 as they travel rearwardly through the straight 'slots 48.

With the barrel 18 in its forwarde-most posi- .tion, the-lugs 5'! are engaged in the forward ends of the axial slots 48. When the barrel moves rearwardly the lugs .54 move to the rear in the axial slots and move the switches 50 out of their paths as they travel rearwardly. The instant the lugs a5! :pass the switches 58, the latter swing back to their active positions under the action of their springs. It is .to be noted that the engagement of the lugs 51 in the axial slots 48 holds the sprocket :39 against rotation throughout the recoil stroke .of the barrel 18. When the barrel :18 moves forwardly during the counter recoil stroke, the lugs 5| travel forwardly in the axial slots :48 until they encounter the switches .50. The switches 50 direct the lugs 5| into the helical slots :49 and as the forward movement continues, the lugs travel forwardly in th helical slots. The cooperation .of the lugs 5| with the walls of the helical slots 49 rotates the drum 4-5 and sprocket 3. 9. By the time the lugs 51 move out of the slots 49., past the switches 52, into the adjacent axial slots 48, the sprocket 39 will have been turned The re-entry of the lugs 51 into the axial slots 48 definitely terminates the rotation of the sprocket :39. Thus during each recoil stroke the sprocket 39 is held stationary, and during each counter recoil stroke the sprocket is rotated '60", and then brought to a stop in a defi, nite angularposition.

The invention provides a barrel extension 53 of special construction for receiving and cooperatmg with the plurality of bolts 87. The extension 53 is secured to the rear end of the barrel 18 to operate axially in the forward portion of the rece'iver 18. It is preferred to construct the exten sion 53 as an integral member provided at its forward end with a tubular boss 540 for receiving the rear-end of the barrel 1-8. The barrel and 8X- tension are connected by cooperating interrupted splines 550 and a spring latch 5'68 engages in a notch "561 in the extension to hold the barrel and block against relative angular movement in the "relationship where the splines are in cooperation. The body of the barrel extension '53 has a longitudinal opening 54 in axial alignment with the bore of the barrel 48. The major, generally rectangular portion of the extension 53 is cut away at one side, the lower side, as shown in Figures '20 and 23, to provide clearance for the sprocket 33 and other elements. The opening 54 is cylindrical and is proportioned to successively receive the individual bolts.

Efi ective lock means is associated with the barrel extension 53 to lock the bolts 81 in the openm .54 for the .nring of the rounds. The opposing walls of the extension 53 have aligned generally rectangular windows or openings 55. Lock blocks or jaws 55 are arranged in the openings 55 for movement toward and away from the longitudinal axis of the opening 54. The jaws 56 may be socketed at their outer faces to reduce the weight. Series of teeth or serrations 51 are formed on the inner faces of the jaws. The serrations haveabrupt forward faces and inwardly and forwardly sloping rear surfaces. An. axial groove 58 extends through each series of serrations 51. Theend' walls of the openings 55 are preferably concave and the ends of the jaws 55 are correspondingly curved to conform thereto.

The lock means of the barrel extension 53 further includes a rack mechanism for actuating and retracting the jaws 55. This mechanism embodies a substantially U-shaped member 59 arranged at the rear of the extension 53. Two pairs of spaced rods 60 are fixed in openings in the member 59 and extend forwardly therefrom to slidably operate in axial openings BI in the walls of the extension 53. The openings 5! partially intersect the jaw openings 55, so that the rods 60 may cooperate with the jaws. The rods 60 are in the nature of actuating members or racks having series of pitched or inclined rack teeth 52 formed on their opposing sides. l The teeth 52 are parallel but are pitched with respect to the longitudinal axes of the rods to be diagonal relative to said axes. The diagonal rack teeth (52 may be formed by machining angular grooves in the rods. The opposite sides of the jaws 56 have correspondingly pitched diagonal teeth 63 meshing with the teeth 62 of the rack rods; see Figures 25 and 30. The direction of pitch or inclination of the

mating rack teeth

62 and 63 is such that upon forward movement of the rods the jaws 56 are moved inwardly relative to the axis of the opening 54 by the cooperating teeth and upon rearward movement of the rods, the cooperation of the teeth moves the jaws outwardly. It is to be observed that both the actuation and retraction ofthe jaws 55 are positive and rapid and that the movements of the jaws are simultaneous and equal. Simple forward and rearward movement of the rack member 59 with respect to the barrel extension 53 effects actuation and retraction of the two jaws 56. with the opposite sides of the jaws 56 normally prevents both inward and outward radial movement of the jaws.

The breech bolt assembly is an important component of the mechanism provided by the invention. This assembly is movable axially in the receiver Ill and embodies a multiple bolt unit that is intermittently rotated during each complete cycle of operation of the gun. The bolt assembly includes a traveling carrier or spider 64 having two elongate tubular bosses 65 which receive and ride on the above mentioned guide rods 41; see Figures 7 and 8. The rods [1 support the bolt assembly for free axial movement. The

carrier or spider 64 also carries a tube 66 which 1 receives the rear portion of the gas piston extension 35. The piston extension 35 and the tube 66 may have sliding spline engagement to assist in preventing undesirable relative rotation between the parts. The piston extension and the spider tube 66 are related for relative axial movement, and the invention provides a slack or lost motion connection between these two elements.

The lost motion connection between piston ex- The engagement of the rack rods 50 tension 35 and the bolt assembly includeswhat I will term an actuator 61 see Figures 9, 11 and 15. The actuator 61 is a tubular member surrounding the spider tube 56 and related thereto for axial movement. A longitudinal gap or slot 68 is provided in one side of the actuator 61 and the actuator has three circumferentially spaced elongate openings 69 in its wall. Blocks or jaws 19 are arranged in the openings 69 and are received in elongate axial slots 1| in the tube 66; see Figure 9. The jaws 10 are capable of. longitudinal movement in the slots 1| whereby the actuator 61 may move longitudinally with respect to the bolt assembly. The jaws 10 may engage the ends of the slots H to limit this relative movement and the end, of the actuator 51 engages the spider 64 to assist in limiting the rearward travel of the actuator with respect to the bolt assembly. Teeth or serrations 12 are provided on the inner faces of the jaws 19 to mesh with similar serrations 13 on the piston extension 35. The engagement of the

serrations

12 and 13 serves to connect the piston extension 35 and the actuator 61. The jaws 10 are movable radially in the openings 59 and means are provided to yieldingly urge the jaws outwardly so that their serrations 12 will not interfere with the insertion of the piston extension 35 into the tube 66. External circumferential grooves 14 are provided in the actuator 61 and intersect the openings 69. Partially circular springs 15 are arranged in the grooves 14 and have'their ends anchored to the actuator. The springs 15 pass throughopenings in the end portions of thejaws 10 to urge the jaws outwardly. In addition to urging the jaws 10 to their outward positions, the springs 15 hold the jaws assembled in the actuator 51.

cam means is provided to normallyhold the jaws 18 in their inward positions where the

teeth

12 and 13 cooperate to secure the actuator 51 to the piston extension. An internal circumferential groove 16 in the actuator 51 carries a partially circular cam member H. The inner surface of the member H has spaced cam lifts 18 which are cooperable with the outer sides of the jaws 10. Upon turning of the member 11 in one direction lifts 13 may be brought into cooperation with the jaws 10 to force them inwardly and bring the teeth 12 into engagement with the teeth E3. The cam member 11 is movable between the position illustrated in Figure 11 where the lifts 18 hold the jaws Ill inwardly and a position where the springs 15 may return the jaws to their outward positions. Latch or detent means are provided to releasably hold the member in its two positions. Detents 19 are formed on the exterior of the member 11 and are cooperable with shoulders on the actuator 61. The cam member 11 may be turned to a position where one detent engages the adjacent shoulder 80 to releasably hold the member where the jaws 10 are retracted. Openings 8| in the wall of the actuator 61 are adapted to receive the detents 19 to retain the cam member 11 in the position where the jaws 10 are actuated. The detents 19 have sloping surfaces whereby they may be readily released from the openings 8| to allow the cam member 11 to be moved to the position where the jaws 10 are released. The cam member TI is slotted circumferentially at each side of the detents 19 to provide the flexibility and resiliency necessary to snap the detents into and out of cooperation with the shoulders 80 and openings 8|. It will be seen that upon depressing the detents 19 the cam member 11 may ing' the sloping" faces of the teeth" 51.

be turned between its two positions to actuate and release the toothed jaws T0. The" releasable slack connection between the bolt assembly and the pistonextension 35 afforded by the actuator 61 described above, is such that the bolt assembly is moved rearwarclly and forwardly with each full cycle of operation of the piston 34 by the gas pressure and spring 36. The lost motion allowed by the construction described above serves to control the sear and hammer mechanisfii and to permit other actions to be subsequently described.

The bolt asse'r'nbl'y further includes a tube 82 threaded in" an opening inthe spider 64- to extend forwardly from the spider in parallel relation to the barrelt8; see Figure 1'3. A shaft 83 extends through the tube 82 and is supported for rotation therein by spaced bearings- 84. A ring 8'5 is keyed or otherwise fixed to the for- Ward portion of the shaft 83 to carry the bolts and a similar ring 86 is fixedto the rear portion of the shaft 83 for a purpose t'o'be later described. The bolts 81 are fixed to" the ring 85 to be equally spaced circumferentially and tob'e in parallelrel'atiori' to the' barrel l8'. In the particular gun illustrated there are three bolts 8'! spa'c'ed 120 apart. Projecting arms 88 on the rotatable ring 85 carry the three bolts 81. The bolt assemblies are identical and I will proceed with a detailed description of one of th'in it being understood that this descripti'o'rlappl'ies to all of the" bfilt units;

Each boltll'l includes elongate way an that 1 is generally rectangular in transverse cross sectioiii The bolt body 89 is proportioned to readily enter the opening- 54 of the barrel extension 53 and is provided at its opposite sides with serrations 90 for cooperating with the serrations 51' of the'jaws 56'. I*-he serrations QUhaV'e'abrupt rear faces fol locking with the abrupt forward faces of the serrations 51, and have outwar'dliv and iearwardly sloping forward surfaces for engagv Longituuin'al slotsat are' provided in the bolt body as for the purpose which will later becomea'pparent, and extend through the" sets of serratlons 9'0 to divide theserrations in' spaced'se ies. Upon forward movement of the bolt assexiibl'y, the b'olt 81, which is aligned with the barrel t8,

enters the opening 54 and introduces the new round nto th'e'fir'ing chamber 92 of tiie'barre Each bolt 81 is equip ed with extr'ac tormeans for extracting round- R. from the" ammunition belt B and rot retainin the round as the belt moves Y rearwardly and then forwardly sothat the rouhd'is'int'rodllced into the fi'rifigdhan'lbef. The extractor means further serves to withdraw the empty case renewing: firing the round" and later introduces the empty case intoth'b'lt 13'.- The extractor" means includes pawns 94' 'ek'teridi'rig through the grooves 91' tobe partially contained and guided therein. The above mentioned grooves sum the breen jaws so'receivetne protrading portions of the pa'WIS" 94' Wheh" the bdlt is locked in the breech block. The Dawls 9' '82- end beyond the forwar ends or the" bolt say as asa tneir promoting portionshave as sea asses 95 provided with nterns-1' shoulders at for engaging and grippihg the flange 9 1 at the base of the cartridge case;- The snbmaersss 'alie alienateand tempt tocoriniml to" the" flange S'ICand-thefor'ufard internal surfabesf of the flaw] sta or tiietbzt' bod 98 for receiving the flange 9] or the cartridge case, and thepawl noses extend into the socket for cooperation with the flange. I M H The rear portions of the extractor pawls 9 4 are mountedfor movement and a mechanism is provided to impart a combined forward and lateral motion to the; pawls to' free the noses 9 5 from the flanges 91 of the empty cartridge case after the latter, hasbeen re-inserted in the any.

munition belt B. The bolt body 89 has a longitudinal opening 99 and a tube 1'00 enters the rear end of the opening. The tube H10 issecured in the opening 99 by transverse pins lfll engaged in openings in the'bol-t body and cooperating; with notches in the tube. Thetube it!) extends be:- yond the rear end of the body 89 and has a T- head which is notched at itsends to form' split l'u'gs )2; see Figure 17. The pawls 94 have reduced end portions which are slidably received in thelussjM: Pins 1% are engaged in trans; verse openings in the rear corner portions'jof the body, 89 and pass through the grooves 91. Eorwardly and lateraliyinclined slots 104 are formed in the pawls v9 and receive ,the pins 1-03; see Figure 12'. The cooperation of the pins H33 and slots HM directsthe pawls 9'4 forwardly and outwardly when actuated. v 4

The means for operating thepawls 94 further includes yoke-like actuators I05 which straddle the lugs lfiZ, and the adjacent portions of the pawl's'; Pivot pins; 106' are engaged in openings in the'actuatorsIBSandthe pa-wls 94'to pivotally connect these elements; The split lug-s fli2 have transverse openings H17 registering with longitudinal slots H18 in-therear portions of the pawls 9t; Th'eside walls of-the actuators I05 have rearwardly and laterally inclinedslots I09 which register with the openings H11. Pins H0 pass through the slots I03, the openings I01 and, the longitudinal slots I08.- The en agement of the pins H0 in the openings I01 of the rigid lug l llz restrains the pins against bodily movement. When the rear portions of the actuators Hi5 are pressed inwardly towa-rd the longitudinal axis of; thebolt body 89'the cooperation of the inclined slots I09 with the pins H0 cams thejactuators forwardly. The intermediate pins 106 being angagedin confiningopenin'gs inthe actuators and pawls 94, transmit this forward movement. to

the pawls. The engagementof the inclined slots Hit of theiorwardlymoving pawls 94 'withthe pins I03 imparts a forward and outward direction ofmovement to the pawls. This movement disengages the pawl noses 85 irom the flange 91 freeing the bolt from-the empty case.

Means is provided to normally urge the; actuators N15 to positions'where the pawls 94 are in active gripping engagement with the round flange 91. This means includes a; sleeve H1 slidable on the tube and forked at its rear end to partially straddle the side parts of the uat r .0. nd, Pres n re r er lyia ins shoulders HZL j The 'actuators I05 have forwardly facing hooks lltengagi'ngtheshoulders H2. A 05 spring" 1'4 suirouhds'tlietlibe l'flband is engaged under compression between a shoulder on the wa o t eigd i e' amthe f r d f the sleeve ll l-.- Thefsprin'gll! urges the sleeve HI ream-nar so that the cooperation of the sh 'uisers m withthe hook-s n3 pivots the tuatdrs I05 outwardly or later-ally. The spring M norm ny holds tiie'actuators' its in theposltibns wher mention at are fully actuated.

any appro riate means may" be" p'r'oi 'id'ed' for actuating the extractor pawls- M" to free their 11 noses 95 from the cartridge flanges 91. In the simple case illustrated, cam projections H5 are suitably located on the walls of the receiver I to be engaged at the proper time by the actuators I05. The outer surfaces of the pawl actuators I are inclined rearwardly and laterally, and upon contacting the cams H5, produce inward movement of the actuators toward the longitudinal axis of the bolt assembly. As above described, this movement results in forward and lateral movement of the pawls 94 to open their round-gripping noses 95. It is to be understood that other means may be utilized to operate the pawl actuators I05, and the invention is not to be construed as limited to the use of the cams I I5 but is to be considered as contemplating any practical operating means.

Each bolt 81 further includes a firing pin H0 and a novel safety means for the pin. The firing pin H6 is arranged longitudinally within the tube I00 and is capable of limited axial movement. Its forward end portion is pointed and operates in a reduced opening II'I leadingto the forward end of the bolt body 89. A flange II8 on the pin III; is engageable with the forward end of the tube I00 to limit the rearward travel of the pin and may engage a shoulder on the wall of the opening Hi to limit the forward travel of the pin. A spring II9 surrounds the pin IE8 and is engaged between a rearwardly facing internalshoulder in the tube I00 and a sleeve I20 surrounding the rear portion of the firing pin. The rear end of the pin H6 is exposed at the end of the tube I I0. The above mentioned safety means includes the sleeve I20 surrounding the rear portion of the firing pin H0 and slidable within the tube I00. A series of circumferentially spaced longitudinally extending grooves I2I is provided in the rear part of the firing pin I IE to be Within the sleeve I20. The end walls of the grooves I2I curve'or slope outwardly to the periphery of the pin H6. A ball I22 operates in each groove I2I and rides on the internal surface of the sleeve I20. The rear end of the sleeve I28 is exposed at the end of the bolt body 89 and may be projected slightly from the end of the firing pin. The spring II9 urges the sleeve I20 to the rear end and the balls I22 engage the end walls of the grooves I2I to limit rearward travel of the sleeve relative to the pin H6 and to transmit the rearward spring pressure to the pin. In the event that the firing pin H6 is moved forwardly independently of the sleeve I20, the balls I22 ride up the sloping end Walls of the grooves HI and bind to prevent actuation of the firing pin. However, when the sleeve I20 is struck first, or when the sleeve and the firing pin are simultaneously moved forwardly, the balls I22 remain in intermediate position and the firing pin is free to operate.

During each reciprocation of the bolt assembly its three bolts 81 are turned as a unit a distance of 120 to provide for the required sequence of round extracting, insertion of the round into the firing chamber 92 and the insertion of the empty cartridge case into the belt B. The present invention is not primarily concerned with the means for effecting this rotation of the bolts 81, except as such means may occur in combination with the elements of the invention, and it is contemplated that the bolts may be rotated by any appropriate means actuated either by the gas cylinder mechanism or by the recoil or counter recoil of the barrel I8.

In the drawings there is illustrated in a more or less schematic manner, one means for producing the required rotation of the bolts 81 during the forward stroke of the gas piston 34. This means includes a tubular drum I25 secured to the rear wall I4 of the receiver I0 and a tube or rod I26 secured to the shaft 83 of the rotatable bolt unit and extending rearwardly into the drum. If desired, the rod I28 may be a simple extension of the shaft. A collar or flange I21 is fixed to the rod I26 and operates in the drum I25. Three axial slots I28 spaced 120 apart are provided in the walls of the drum I25. The slots I28 are connected by pitched or helical slots I29. The slots I28 and I29 are of uniform width and are adapted to slidably receive lugs I 30 formed on the periphery of the flange I21. There is 9. lug I30 for each axial slot I28 and the lugs have pairs of parallel side surfaces adapted to slidably ride along the Walls of the axial slots and helical slots. The helical slots I29 join the rear end portions of the axial slots I28. Each helical slot I29 extends from immediately adjacent the rear end of one axial slot to join the next axial slot a relatively short distance from its rear extremity. This leaves the major forward portions of the axial slots I28 entirely uninterrupted. A pivoted switch I3I is provided at the rearmost end of each helical slot I29. The switches I3I are spring urged to the positions illustrated in Figure 6 where they direct the lugs I30 from the axial slots I28 into the helical slots when the lugs are traveling forwardly. The switches I3I are swung out of the way by the lugs as the lugs travel rearwardly in the axial slots I28. Similar switches I32 are provided at the forward ends of the helical slots I29. The switches I32 are pivoted and spring urged to positions where they prevent the lugs I30, traveling rearwardly through the axial slots I 28, from entering the helical slots.

Upon rearward movement of the gas piston 34, the lugs I30 travel rearwardly through the axial slots I28 from the forward ends of the slots .to their rear ends. This engagement of the lugs I30 in the slots I28 prevents rotation of the bolts 81 and assures true rearward movement of the bolts so that the bolt in the barrel extension 53 moves out of the extension without interference and the bolt that has engaged the new round R in the belt B withdraws the round from the belt without any angular movement. The lugs I30 travel substantially the entire lengths of the slots I28 and are prevented from entering the helical slots I29 by the switches I32. When the bolt assembly begins to move forwardly under the action of the spring 36, the lugs I30 almost immediately encounter the switches I3I and are diverted thereby into the helical slots I29. The lugs I30 travel forwardly through the helical slots I29 and their engagement with the slots of the stationary cam drum I25 produces rotation of the bolt assembly through a distance of Owing to the pitch of the slots I29, this rotation of the bolt assembly is rather abrupt and the angular movement is completed by the new round carried by the bolt 81, which is being brought into alignment with the breech before the round can interfere with the barrel extension 53 or the parts associated therewith. Upon leaving the helical slots I29, the lugs I30 engage the switches I32 and swing them out of the way. Upon passing out of the slots I29, the lugs I 30 move forwardly in the axial slots I28 and remain in the axial slots until the forward stroke of the greasy? gas piston has been completed. The engagement of the lugs I in the axial slots I28 definitely maintains the bolts 81 in the angular position where the new round is in alignment with the breech, and where the empty cartridge case is aligned with its empty belt link L for insertion therein. It is to be observed that the bolt assembly is turned in the same direction as the sprocket 30 but is turned 120 with each complete cycle whereas the sprocket is turned only 60. The cartridge feeding mechanism above described forms the subject of my copending eppication Serial Number 659,985, filed April 5, 1 46.

The above described aws 56 of the barrel extension 53 and rack mechanism for operatin the jaws are dependably latched in positions where the bolt 81 carrying the new round B) may freely enter the barrel extensionupon forward movement of the boltassembly without interference by the jaws 56. The latch mechanism for holding the jaws retracted is released or conditioned for release during forward movement of the gas piston 34 by a part associated with the above described actuator 61. The latch means includes a tube I33 fixed in an opening I34 in the intermediate portion of the member 59. The tribe I33 projects forwardly to extend along one side of the breech block 53 see Figures 18 and 23. The tube I33 is slidably guided in openings [-35 of spaced lugs I36 projecting from the block. The parts are related so that the tube I33 remains in cooperation with the openi'ng's I35 throughout the entire range of movemerit of the rack supporting member 59'. A sleeve I3'I surroundsthe tube I33 and has an internal shoulder I38.- The sleeve I3'I normally bears rearwardly against the rear lug- I3B. A spring I39 is arranged under compressionbetween the forwardlug I 33 and shoulder I38 to urge the tube I33 and sleeve I31 rearwar'dly. The sprin [39 isof sufficient strength to normal-1y hold the member 59 it'sre'armost position where the jaws 56 are fully retracted. V

The tube I33 has an elongate axial slot I40 receivin a latch MI. The latch hasan inwardly projecting ear I42 on its inner edge received in a notch-- I43 in the sleeve I=3'I- and operating in an axial slot I44 in the wall of the barrel exten- Sidll 53; See Figures 23 and Z4. groove I45 isrormed in the exterior oi the sleeve I 3 1 and receives a; Wire ring I46. The ear I42 of the latch has a transverse opening I41 and the ring I46 passes through the opening to retain the latch MI in the slot I40; see Figure 19. The latch I4 I also has a projection I48 on its forward and freely received in the opening of the tube I33. An ear I49 projects from the outer edge of the; latch MI and is engaged by the rear end of the sleeve I31. The spring urged sleeve I31, acting onthe forward edge of the latch MI and its" ear I49; normally urges the latch to the full line position of Figure 23. The longitudinal outwardly facing edge of the Iatch M-I- has an abrupt shoulder I50 facing rearwardly. The shoulder I56- ispitched forwardly and inwardly to some degree whenthe latch I4 I is in the normalifill line position of I figure 23 The same edge of the latch I-4I has a shorterforwardly facing shoulder I 5 I which is also pitched forwardly and inwardly. The rear end surface $52 of the latch is engagea-ble'with the end wall of the slot I 40 to normally prevent forward movement of the member 59 and" its ra'ck rods 60 relative tothe barrel exterision 53-. This surface of the latch is slightly An annular inclined and rounded away so as to clear the end wall of the slot I40 and enter the tiibe I33 unon slight swinging movement or the latch MI in the direction indicated by the a'i'iotv in Figure 2e. The inner edge of the latch I41 has a sloping shoulder I53 engageable with the rear end of the barrel extension 53. It will be seen that the spring I39 holds thelatch MI in the full line post tion of Figure 23 where the 'siirface I52 engages the end wall of the slot I40 to positively prevent forward movement or the member 59 and rack rods Bl] so that the jaws 56 areretaihd their retracted positions. I

Means is provided for releasing the latch In just prior to forward actuation or the rack memher 59. This means includes arod I54 carried by the actuator 61. The actuator has a yoke I55 open to its interior and the rod I54 is provided with a grooved flange I56 seated in the yoke so as to he normally-rigid with the actuator; The engagement of the flange i 56 in the yokel 55 positively holds the rod I54 againstangular movement. The rod I54 extends hoth forwardly and 'r'earwardry from the yoke I 55, and its longitudinal axis is coincident with the aids of the tube During the final portion of forward motion of the gas piston 34 and the actuator 61, the rod r54 enters the tube I33. The above described notch 68 in the actuator freely ulcers or passes the lugs I35 of thebarrel extension during this movement. The advancing end of the rod I54- may be somewhat beveled to readily enter the time [33. one side of the rod :54 has an inwar'dly'facing notch I51 and is cut away to some extent to clear the rear portion of the latch I when entering the tube. The end of the forwardly moving rod its is adapted to strike the pitched shoulder Iii? t0 Swing" the latch I to the broken line position or Figure 23. This pivotirrg of the latch I II moves the portion of the latch occurring between the shoulder I51 and the surfade F52 into the notch I151 0f the fod I54. The engagement of the rod I54 with the shoulder I50 may not be sufiicient to cause the latch to swing the entire distance, but the' cooperation or the rear" wan of the slot I 40 with the rounded end surface I52 of the latch completes the swingin of the latch, When the latch I4I has been swung to the position of Figure 24, the racl' z'rods 60 are free to move forwardly and actuate the jaws 56 to obfielat With the .boltserrations It is to be observed that during forward movement of the bolt assembly the actuator GT in its forward position relative to the spider 64 because actuator in effect, pulling ti e sp der and belt assembly forward. Accordingly, the latch in is release orconditioned for release by the rod we, on the h ading" actuator, before the yoke I55 engages the member 59- or before the spider 64 of the bolt assembly comes into contact with the yoke I55. When the bolt assembly is drawn forwardly by the actuator 61, the rod I54 first releases or conditions the latch I'4I for releaseand the yoke" I5'5- then engages the member ta. The spider 64 moves up to its finalpo'sition to introduce the bolt 81 into the block 53-, inertia carrying thebolt assembly forward while the actuator lags slightly by reason of its engagement with the latch. The actuator continues to move forwardly after the spider stops, andthe actuator strikes the member 59, to drive the rack pins 60 forwardly and" actuate the breech block jaws 55.

Vlil'ie'rithe jaws-t6- are fully actuated, the latch v on iliustrat'ed in' Figure 24. Withthelatcli in this positioii-its'ene'suriaoe It:

gngag d with the .r

. anesthesia e s g;

ernefi with thei nature bfi, tne hammer mfi i a i use employed e xcept insofar as it secure n eem was greases was; use enemas ma ma as drum 126 position; the ring :86 so that the roeves. 62 a'rE successively ali e with striking pin I65. The parts are related so that the pin I65 is aligned with the hammer I6I and the pin is normally urged to the rear by a light spring I66. The hammer IBI, when actuated, moves through a guide groove I63 and strikes the pin I65, which in turn, strikes the sleeve I and firing pin H6 of a .bolt assembly to fire the round R.

The means for actuating the hammer I6I includes a spring I61 arranged under compression between the sleeve I60 of the hammer and a head I68 on the rear end of the tube I59. The spring I 61 surrounds the tube I59 and is adapted to drive the sleeve I60 and the hammer I6I forwardly with considerable force. An arm I69 .projects radially from the rod I54 and operates in a slot I10 in the tube I59. The sleeve I60 of the hammer has a stop lug I'II on its forward end engageable with the securing flange of the tube I59 to limit the forward movement of the hammer sleeve I 6|] and stop it in a position where the arm I69 is directly in front of the sleeve.

When the gas piston 34 begins to move rearwardly, the actuator 61 moves rearwardly with respect to the spider 64 and the rod I54 moves rearwardly in the tube I59. During this relative movement between the rod I54 and the tube I59 the arm I69 moves the sleeve I 60 rearwardly along the tube to compress the spring I61. A pivoted spring urged latch I12 is carried in a slot in the tube I59 and engages in a notch I13 in the hammer sleeve I60 to releasably latch the hammer in its cocked position; see Figure 6A. This occurs immediately before the actuator 61 engages the spider 64 topush the spider and 3G iminat @chaLr ge the gun; manually: and: to: initiate and gunzeperatiorni l fer examplaa habiieii :shnwa- 'cheiniatitia z ytirinay becenini cteid with: the;

p. I arteries :of the :re'eeiver N: to: provid :for: h nd:

. charging iof thezgumby pulling the: no;

hushirig iiil isiseeinfed inian. opening in the spider 64 and slidably carries a rig means: initiateandzterminate:eperatinh. if:

the gunv Such solenoid contr'el mechanisms are common in the art, and form no part of the present invention and are therefore considered unnecessary to an understanding of the construction provided by the invention. This invention is concerned with the barrel extension and bolt assembly combination and elements associated therewith, and while a substantially complete gun has been disclosed it is to be understood that this disclosure has been provided for the purpose of assuring a better understanding of the construction and operation of the novel features and is not to be considered as restricting either the scope or the application of the invention.

Operation Substantially complete operation of the gun will be described below in order to fully disclose the purpose and operation of the barrel extension and bolt assembly. To condition the gun for operation a suitable magazine, not shown, is applied to the frame I6 and the ammunition belt 13 is trained over the sprocket 39. At least one link L of the belt B is empty so as to pass the barrel extension 53, and a live round is introduced into the recess in the forward end of the bolt 87, which is to be aligned with the breech, so as to be gripped by the pawl noses 95. When the sprocket 39 has been supplied with the belt B, the bolt assembly is manually moved to the rear by the charging cable I90. During the rearward travel of the spider 64 and bolt assembly, the hammer I6I is cooked as above described. The lugs I30 travel rearwardly through the axial slots I38 and the bolts 81 move rearwardly without rotation. The rearward movement of the actuator 61 with the bolt assembly causes rearward travel of the gas piston 34 and the spring 36 is compressed so that energy is stored therein. Upon completion of rearward travel of the bolt assembly the gun is ready for operation.

The bolt assembly may be released for forward movement under the action of the spring 36 by a suitable control device, either direct or remote. For present purposes it may be considered that the operator merely releases the charging cable to allow the spring 36 to move the bolt assembly forward. During the first phase of forward movement of the spider 64 and bolt assembly, the lugs I30 move through the helical slots I29 to rotate the bolts 120. This brings the bolt 81, which is carrying the live round, into alignment with the cartridge chamber 92. During the remainder of the forward motion of the bolt assembly, the bolts are held against rotation and the bolt 81, carrying the round, enters the barrel extension and introduces the round into the cartridge chamber. The actuator pawls 94, of an empty bolt 81, cooperate with the next round in the belt B to have their noses 95 grip the flange 91 of the round. As above described, the rod I54 enters the tube I33 and contacts the latch shoulder I50 to release the latch I4I so that the member 59 and the rods 69 may move forwardly to operate the jaws 56. The latch I4I operates to retain the member 59 and the rods 60 in their forward positions where the jaws 56 are actuated so that the bolt 81 is locked in the barrel extension. During the final phase of forward movement of the bolt assembly and actuator 61, the cam II4 releases the latch I12 and the hammer I6I is actuated to fire the round. Upon firing of the round, the gas pressure developed in the bore of the barrel I8 acts on the gas piston 34 to drive it rearwardly. R'ear- Ward movement of the gas piston moves the actuator 6! to the rear. This releases the latch I4I as described above so that'the spring I39 may move the rack rods 66 to the rear and retract the jaws 56. The initial rearward movement of the actuator 61 also compresses the hammer spring I61 and cocks the hammer I6I. Thus by the time the rearward travel of the actuator 61 relative to the spider 64 is completed the jaws 56 are retracted to release the bolt 81 and the hammer I6-I is cocked. The actuator 61 then engages the spider 64 to move the bolt assembly to the rear. During rearward movement of the bolt assembly the lugs I36 move through the am'al slots I26. The rearward movement of the bolt assembly also results in withdrawal of the empty cartridge case from the chamber 92 and the new round gripped in the pawls 94 of a bolt 81 is pulled out of the belt B. Thus one empty cartridge case and one live round are moved to the rear with the bolt assembly. 'During the recoil of the barrel I8, accompanying firing of the round, the lugs travel rearwardly through the axial slots 48 and the sprocket 39 remains stationary. Upon counter recoil of the barrel I8, the lugs 5| move through the helical slots 49 to rotate the sprocket 39 and thus position the sprocket to receive the empty cartridge caseand to bring the next round into position for extraction by the pawls of the now empty bolt 81. The spring 36 initiates forward movement of the bolt assembly immediately following rearward travel of the assembly. During the forward stroke of the bolt assembly, the lugs I30 cooperate with the helical slots -I29 to turn the bolt assembly to the position where the new round is aligned with the firing chamber 92 and the empty cartridge case is aligned with its emtpy link L of the belt 13. The lugs I36 move into the axial slots I28 and during the remainder of the forward motion of the bolt assembly the bolts are held against rotation. During the final phases of forward motion of the bolt assembly, the new round lit is introduced into the firing chamber 92 and the bolt 8'! enters the barrel extension opening 54. The rod I54 of the actuator assembly releases the latch I 4! so that the jaws 56 may be actuated to lock the bolt in the barrel extension. The empty cartridge case is introduced into the empty link L of the bolt during the final forward motion of the bolt assembly, and the actuators I05. of the bolt 81, which carries the emptycartridge case, are operated through engagement with the cams I I5 so that the pawls 94 release the empty case. The pawls 94 remain in the released condition until the bolt assembly begins its rearward travel during the next cycle of operation and the released pawls allow the empty case to remain in the belt B. The final phases of forward movement of the actuator 61 release the latch =I'I4 so that the hammer |6I is actuated to fire the round. The above sequence of operations is repeated during successive automatic firing cycles of the gun.

Having described only a typical form of the invention, I do not wish to be limited to the specific details herein set forth, but wish to reserve to myself any variations or modifications that'may appear to those skilled in the art or fall within the scope of th following claims. l

z I claim:

1. A gun mechanism having a barrel and a barrel extension provided with an opening and characterized by a bolt assembly including a series of bolts supported for intermittent rotation as a single unit, each bolt being engageable in the opening of the extension, serrations on the bolts, means supporting said assembly for axial movement toward and away from the extension so that the individual bolts are entered in the opening of the extension, and serrated lock means on the extension for cooperating with the serrations of the bolts to lock the bolts in the block.

2. A gun having a barrel and comprising an extension on the barrel having an axial opening aligned with the barrel and a lateral opening, a bolt to be introduced into said axial opening and having serrations, a lock jaw contained in said lateral opening for movement in a radial direction relative to said axial opening and having serrations for cooperating with the first named serrations, and translatory rack means for moving the jaw in said radial direction, to bring its serrations into cooperation with saidfirst named serrations.

3. A gun having a barrel and comprising an extension on the barrel having an axial opening aligned with the barrel and a, lateral openinga bolt to be introduced into said axial opening and having serrations, a lock jaw contained in said lateral opening for movement radiallyof said axial opening and having serrations on its inner side for cooperating with the first named serrations, inclined rack teeth on the jaw, and an actuating member movable axially on the extension and having inclined teeth cooperating with the first named teeth to move the jaw radially in said lateral opening for the purpose of engaging and disengaging the serrations.

zgeooisev 41- A" gunhating'n barrel' an'd comprising an extension 'on thebarrelha-ving 'an" axial" opening aligned with the barrel and a lateral opening, a bolt to beintroduced into saidaxial openingand having serrations, a lock jaw'con'tained in said lateral opening for movement radially of said axial opening and" having serrations for cooperating with the first na'me'd' serrations; diagonal teeth on opposite sides of the jaw; andspaced rack rods movable axiallyof' the extension'and lfavin'g' diagonalteeth meshing with the first named' teeth tomove'the jaw between positi'ons retracted from the axial 3 opening and positions whereits'- serrations mesh with the serrations ofthe bolts.

5? A gun"havingfa barreland comprising an extension on the barrel having'a main'axial open ing aligned with the-barrel, spaced" axial bores and radial openings communicating with the main opening, a bolt to be introduced axially into; the main opening ha'v'ing serrations, block'- lile jaw's contained in theradial openings and supported therein-for radial movement, the jaws lia'v'itig 's'erra-tions" for meshing withthe serrations of the bolt, dia'gorial raok teeth 'on-"th'e jaws,-ra'ck rbtl's shiftable in said" bores and" having teeth chbperating with" the teeth of the jaws to move the jaws'radially between retract'etl po'sitionsand positions where their serrations engage thesertension.

6. A gun" having a barre'l comprising an ex tension on the barrel i having" an opening" aligned with the barrelL-a b're'ch 'bolt movable axiau into and out of the opening, jaws carried in the extension for transverse movemenflbetween positions: clear of the opening and positions where they look the bolt in the extension, and a single latch means: operable to 'releasably latch the-jawsin both of said positions.-

7'. In a gun having a barre'l' the combination of; an extension secured to the barrel" and liav ing an opening aligned with; the barrel, a? breech bolt movable axially-into and out of the" opening; a jaw in the: extension. movable transversely orthe. opening between at position=- clear or the opening to -allow'the entrance-of the bolt therein and an actuated position whereit locks thebolt in the extension, means for moving the .bolt into and:- out" of the opening includingan actuator having: a slack connection with the bolt, and latch means :forholdingthe jaw in; the retracted position and released.- by relative movement be-- tweensthe' actuator and bolt.

8; In a gunhaving; a barrel the combination of: an extensionisecured tm the barrel and having an opening aligned, with the barrel, a breech bolt" movable axially into and out" of the opening a jaw in the extension' movable transversely oi? the opening between awposition clearof the opening to allow entrance of the bolt therein'and an actuated, position where the jaw locks the boltrin the extension-means for moving the-bolt intaand-out of. the opening including an actuator having a slack connection with thebolt, and rack means for moving thesjaw between-saidtwo positions and: controlled by relative movement between the actuator and bolt. 7

Inra gun having-a barrel extension provided with an opening aligned with the barrel} the combination of a breech bolt: movable axially into and out of the opening, a jaw inthe-barrel extension-movable transversely of theopening between a position clear of the opening tot allow entrance of the bolt therein andan actuated position where itlocks the'bolt in the extension, means' for 'moving'the bolt into' and out of the opening including an actuator having a slack connection with the bolt, rack meansfor*moving the jawbetween said two positions controlled byrelative movement between the actuator and bolt, andlatch means for holding the jaw in the retracted position released by relative movement between the actuatorand bolt.

10. In a gun having a barrel extension the combination of a carrier movable axially relative to the barrel extension, a plurality of breech bolts supportedon the carrier for simultaneous intermittent rotation: as aunit so as to be individually alignable with the barrel'extension, lock means the extension for locking the bolts therein, a member for moving the carrier axially, a lost motion connection between the member and carrier, andialatch for the'lockmeans con trolled byrelative movement between themember and carrier.

11; In a gun having a barrel extension the combination of; a" carrier movable axially relative to the barrel extension; a plurality of breech bolts supported on, the carrier for simultaneous intermittent rotationas 'a unit' was to' be indivi'dually alignable with thebarrel 1 extension, a member for moving: the carrier. axially, lock means'for locking'the: bolts in the barrel'ext'en sion, the carrier being; operable-etc actuate the lockmeans when r the" carrier moves toward a the barrel extension; aridr a-lat'ch for holdingthe lock means retracted? and released by said mem. ber"bef'0re thecarrier actuates' the lock means.

12. In agun having; at barrel extension the combination, of, a carrier movable axially relativeto the barrel) extension, a plurality of breech bolts: supported on the carrier for simultaneous intermittent rotationas a unit so as toxbe individually alignable with the barrel extension; a member for moving the carrieraxially, lock: means for locking; the bolts: in the barrel extents-ionpthe carrier being operable to actuate the lockmeanswhenwthe carrier moves toward the block, latch'means-forv holding the lock means in a retracted position and" operable. to latch the lock, means in; itsoperated position; and apart on said member for releasingthe'latch-means to free thelock meanstfor actuation beforethe carrier actuatesthe lockr means while traveling to,- warct the barrel extension: and: operable to release the latch means to: allow: retraction of the lock means when: the member initiates its movement in the direction; to move the carrier away from the? barrel. extension.

13., A gun comprising a barrel, an extension fixedto the barrel; andhaving ani axial: opening constituting a continuation of the bore of the barrel, a spider at the rear of the extension supported for axial movement toward and away from the extension, a circular series of three equally spaced boltssupported bythe spider for rotation, as a unit about an axis parallel with the barrel, the bolts being proportioned so as to be individually receivable in said opening of the extension, andvmeans for imparting. axial movcmentto the spiderandv rotary movement to said series to successively introduce the. bolts; in said opening and. then withdraw them from the samel 14.1A gun comprising, a barrel, an extension fixed; on the; barrel. and-,Ihaving anopening constituting a continuation, of the bore of the: barrel; a circular series of, threelequally' spaced bolts supported for. axial movement as a unit toward and, away fromthe? extension;- andz for rotation as a unit about an axis parallel with the barrel, each bolt being designed for reception in said opening, and means for imparting reciprocating motion and intermittent rotation to said series so that the bolts are successively entered into and withdrawn from said opening.

15. In a gun having a barrel, the combination of an extension secured to the barrel and having an opening aligned with the barrel, a breech bolt movable axially into and out of the opening, jaws 10 carried in the extension for transverse movement between positions clear of the opening and positions where they look the bolt in the extension, inclined teeth on the jaws, a pair of shiftable actuating rack members having inclined teeth for cooperating with the first named teeth to operate each J'aw between said positions, and latch means associated with the rack members for releasably holding the jaws in their said two positions.

ALFRED CORTE.

22 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS