US2965001A - Rocket launcher - Google Patents

Description

Dec. 20, 1960 w, D BOBCO ET AL 2,965,001

ROCKET LAUNCHER Filed May zo, 1954- 4 sheets-sheet 1 -Willilll'rrl.4 D. Einbau v 'E 'Wnll A- Kun-11:1 Rudolph E..5"cE1-\n ATTORNEYS Dec. 20, 1960 w. D. Bosco ErAL 2,965,001

ROCKET LAUNCHER Filed May 2o, 1954 sheets-sheet 2 91S w8 @SNS m..

.Extern K nvvENrofas William D. Ember:

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@um H Lll Dec. 20, 1960 w. D. BoBco ETAL ROCKET LAUNCHER 4 Sheets-Sheet 3 Filed May 20, 1954 ROCKET LAUNCHER 4 Sheets-Sheet 4 Filed -May 20, 1954 www? bb. Q om s m flo o f\ m N pn mh m n .E v n u@ W o WBK am LAE. f dh T1@ M m wm WER m Y e -mmwrmll United States Patent ROCKE'I` LAUN CHER William D. Bobco, Berwyn, and Ewald A. Kamp and Rudolph E. Stern, Chicago, Ill., assignors, by mesne assignments, to the United States of Ameri as represented by the Secretary of the Army Filed May 20, 1954, Ser. No. 431,306

6 Claims. (Cl. 89-1.7)

This invention is an automatic, rapid firing gun.

An object of the invention is to provide a gun having a high cyclic firing rate, of the order of 800 rounds per minute for projectiles in sizes normally associated with artillery.

Another object of the invention is to provide a gun which will index, lire and eject a round with a minimum of moving parts.

Another object of the invention is to provide a gun in which the stripping, ramming and extracting operations of conventional weapons are eliminated.

A further object of the invention is to provide a gun having a barrel, the breech end of which is spaced from a back plate to receive a round therebetween, in axial alignment with the barrel, the case of said round being substltuted for the firing chamber and breech block, conventionally used.

v A further object of the invention is to provide gas operated means for indexing the rounds to tiring position and reciprocating a breech closing collar in timed relation to the arrival and departure of the round.

A further object of the invention is to provide a novel scar mechanism for arresting the movement of the indexing means when the last round has been tired or the external feeding mechanism fails.

A still further object of the invention is to provide ring means on the gun for igniting the booster charge in the round only when the gun is in battery position.

Other objects and advantages will be apparent from the following detailed description and the accompanying drawings, in which:

Figure l is a vertical longitudinal sectional view of a gun embodying the present invention.

Figure 2 is a transverse sectional view to an enlarged i. lscale on the line 2-2 of Figure 1 and illustrating a conventional magazine connected thereto.

Figure 3 is a top plan of the gun with parts broken away.

4Figure 7.

Figure 9 is an enlarged sectional view of the 'breech closing mechanism.

Figure l 0 is. a sectional view of the drive spring assiem-I bly and combined charger. v I Figure 11 is a sectional view of the. lll Pin.

Figure 12 is an enlargedview of the sprocke t,assem bly and its brake mechanism.

Figure 13 is an enlarged detail view of the 'cam slide.

2,965,001' 'Patented Dee. 2o, 1960 lCC Figure 14 is a fragmentary view on the line 14-14 of Figure 9, and

Figure 15 is a fragmentary top plan view of the cover plate.

The present invention was devised to increase the tire power of weapons using gun boosted rocket ammunition wherein the rocket and booster propellant is housed entirely within the cartridge case, herein referred to as a round The rounds are fed to tiring position without belts or links. Therefore such operations as stripping from the belt, ramming, and extracting spent casings from the breech are eliminated with a corresponding saving of time and mechanical parts, as well as a potentially large increase in rate of fire. In our invention the cartridge case serves as the firing chamber of a gun. A sliding collar surrounding the barrel and movable in synchronism with the indexing mechanism, replaces and functionally substitutes for the breech mechanism of a conventional or prior art gun.

In the drawings, wherein for the purpose of illustration, is shown one form of the invention, the reference character 5 indicates the receiver of the gun. A vertical transverse support 6 forms a part of the receiver and is provided with reinforcing side plates 7 (Figures 3 and 5). Trunnion pins 8, Figure 3, are formed on the support 6 for pivotal connection with a suitable mount, not shown. I'he terms forward and rearward" used herein mean, respectively, the movement of components 4toward the muzzle end of the weapon and toward the back plate.

A cylindrical housing 9 is secured at its rear end to the support 6 and at its forward end by upstanding side plates 10 (Figures l and 3) forming a part of the receiver. An internal circumferential shoulder 11 is formed in the housing 9 near its rear end and abuts an external circumferential shoulder 12 on barrel 13 litting, within the housing. The breech end of the barrel extends rearwardly beyond the rear end of the housing 9 and has a portion thereof externally screw-threaded to receive an internally screw-threaded nut or collar 14 for clamping the shoulder 11 against the shoulder 12. As best shown at Figure 9, the forward end of the nut is circumferentially reduced externally to underlie and fit the internally reduced end of the housing 9. A set screw 15 in the housing engages the nut 14 to prevent rotation of the nut relatively to the housing. An additional means for securing the barrel in the housing is provided by a pivoted latch 16 (Figure 9) which is adapted to seat in a depression 17 in the barrel.

Rearwardly of the support 6 and adjacent the rear end of the barrel a bracket 18 is secured to the receiver by screws 19 (Figures l and 3). A guide rail 20 extends the entire length of the upper faceof the bracket and is formed integrally therewith. A second bracket 21 secured to the receiver 5 by screws 22 near the rear end of the receiver also has an integral guide rail 23 extending the full length of the upper face thereof. A shaft 24 (Figures 1, 6 and 12) having a screw-threaded forward end 25 fixed against rotation in a similarly threaded opening in the bracket 18, extends rearwardly through an opening in the second bracket 21. The longitudinal axis A of the shaft 24 (Figure 1) is positioned .parallel to and below the longitudinal axis B of the barrel and is spaced therefrom a substantial distance, as will be hereinafter more fully explained.

-A sprocket assembly 26 (Figures 6 and l2) which is free to rotate on the shaft 24, comprises a sleeve 27 having end sprocket wheels 28a and 28b formed therewith.

A sprocket wheel 29l (see also Figures 2 and 6) spaced intermediate the sprocke't'wheels 28, is also formedintegral with the sleeve 27. Both of the end sprockets 28 ai'efor'n'iedfwith concave recesses30 (Figure l) between adacent-arms lwhich arespacediat 90 degree intervals. Y

The sprocket wheel 29 has similarly spaced arms 32 and concave recesses 33 in longitudinal alignment respectively with the 'arms J31 and 4concave recesses 30 of ithelsprocket wheels 28. The concave recesses of all Aspro'cket wheels are"`shaped to cradle the particular '-type of round to be. used. A

' A'magazine 34 lis shown in Figure 2 wherein rounds R are fed horizontally and Itransversely of the gun 'between upper rails 3S and llower-rails 36 by a presser bar 37 secured to a piston rod 38. The piston -rod has a piston 39 secured thereto for reciprocation in a cylinder 40. Fluid pressure is admitted "to the cylinder through a-conduit 41 from asource, notl shown. It isto be understood that the magazine herein shown is -merely for vthe purpose of illustration andthat many v'different types can be substituted, as occasion demands. f

One form of vround R which is adapted to be used in the present invention is disclosed and claimed 'in va lcoending application of E. A. Kamp et al., Ser. No. 406,618, filed January 27, 1954, for Rocket Round (Ord Case 4044) and comprises a casing 42 which has a cap A43 for closing itsrear end. The cap is formed with a circumferential shoulder 44 which abuts the guide rail 23 on thevrear bracket 21 as vclearly shown upon Figures 1 and 3. At its forward end the casing carries a sleeve 45 iixed therewith -and the rear face of which formsv a circumferential shoulder which is slightly -spaced from'the forward-'face of guide rail 20 of *the forward bracket 18, whereby'each'round as it moves between-the "guide railsis vlrrxitedv in axial motion A"to an *amount less than the clearance-"between the round andthe firing pin face and the rear face of the barrel. The round R may contain a spin type rocket '46, 'a booster charge 47 for initiating ilight and a detonating means 48, -as more specifically described `in theaforesaid copending application. 'A back plate '50 is Asecuredto `the receiver by pins 51 as shown in Figures 3 and 4.

A cover Aassembly 52 is vprovided at its front end lwith two bored lugs I53 which are pivotally'secured in recesses 54 in top of support 6 by pins `55, as shown in Fifures 3 and 5. The rear end of the cover is provided with three transversely-spaced bored lugs 56, Figure 4, which are secured in recesses '57a lat the top of the back plate '50 by a pin 51a. It will 'be apparent on referring to Figures l, 4 and 5 that the cover 52 may be raised when vthe rear pin 51a is removed and the cover pivoted on the front pins 55. Guide ra'ils 57 and 58 are secured to the under side of the cover and-retain the rounds in their respective recesses in the sprocket wheels as they are picked Aup and indexed by the sprocket assembly.

A sprocket brake sleeve 59 is secured against rotation in the rear bracket 21 by a -key 60, Figure 12, and is bored to journal the sprocketshaft 24 and to have axial motion therealong. The forward end of the brake sleeve is enlarged and formed with cam surfaces 61 which coact with similarly'shaped cam surfaces 62 on an insert 63 which is keyed to the rear hub of the sprocket assembly. Figure l2 shows the camsin their position about midway of the indexing movement of the sprocket. The shaft 24 extends rearwardly through an opening 64 in Vthe back plate 50 andhas positioned thereon compression spring means 65 lsuch as Belleville washers, but other types of spring means can be used as found desirable. The spring is confined between washers 66 or the like the forward one of which is urged thereby against the rear end of the brake sleeve V59 to exert a desired pressure by a nut 67 threaded on the shaft 24 rearwardly of the back washer 66. Near the end of the indexing movement of the sprocket the cam surfaces 62 contact the cam surfaces 61 on the brake sleeve and through the cushioning action of the spring means 65 rapidly decelerate the motion of th'c'sprocket'assembly. 'Atthe end of the indexing rotation of the sprocket assembly the at tip of the 'cams 61 and 62 are 'in contact and a round of ammunition is in tiring posit-ion,

at-which time .a dwell in `the .tiring ycycle is effected, as will later be more fully explained. In the present embodiment of the invention, the sprocket assembly rotates intermittently in a counterclockwise direction as viewed from the breech end of the gun. The arms 32 of the intermediatesprocket wheel 29 are bored radially at 70, Figure l2, to house spring pressed rollers 71, 71a, 71b and 71c as best seen in Figure 6. The

rollers are free to rotate on .stub shafts 72 which are" limited in their outward radial movement by pin vand slot connections 73. A spring element 74 'housed ineach of the bores 70 urges the stub shafts and their rollers radially outwardly for -a purpose to be hereinafter more fully disclosed.

As shown in `Figures l, 2 and 3 the gun has been charged and can be fired as soon as a manually operated switch, not shown, is closed. Thereafter firing continues until the switch is opened. An automatic firing switch assembly 75 as shown in Figures 7 and 8 is positioned in openings in the feed side of the receiver and com'- prises two spring pressed contact pins 76 and 77 whieh are insulated from the receiver by sleeves 78 of dielectric material. A bus bar 79 is embedded in the forward -end of the reduced guide tongue of an indexing slide 68, 'to be hereinafter described and engages the two contact pins 76 and 77 to close a tiring circuit to the firing pin assembly 49. The 'bus bar is insulated from 'the slide by dielectric Imateriallt).

The tiring -pin assembly 49 comprises a housing 157, Figure ll, having -a vflangel 158 on one end, and having its other end screw threaded to receive asimilarly screw threaded -nut 159for securing the housing inthe back plate 50. A single electrode 160 -is axially positioned within a bore 163 in the housing 157 and is insulated therefrom by -sleeves 161 of dielectric material. The

bore 163 is internally screw threaded at 164 and receives a similar screw 'threaded retaining lplug 165. A lead 165a from the automatic firing vswitch 75 is connected to the' electrode 160. -A 'helical spring element 166 is housed within an enlarged end of the electrode -and furges a tiring pin 167 into contact with the detonating means 48 in the round. The spring element also serves to conduct voltage to the firing pin.

When the round is tired and the projectile has traveled a short distance into the barrel, the expanding gas from the booster charge 47 finds its way through a port 81, Fig. l, in the barrel 13 and a bore 82 in the support 6 to enter a cylinder 83 positioned beneath the barrel. Slidabiy mounted in the cylinder is a piston S4 having a piston rod 85 which extends rearwardly into engagement with the forward end of an indexing slide 68 to `be-later described. Extending forwardly from the piston 84 isa second piston rod 86 which forms part ofl a buffer assembly 87.' The-forward end of cylinder 83 is closed by screw threaded engagement with'a cylindrical spacer 83a which also acts as a guide forA the piston rod S6. The buffer assembly comprises a cylinder 88 in which a'piston 89 is positioned on and intermediate the ends of an elongated piston rod 90. The forward end of piston rod 90 engages a buffer spring 91 which is restrained within a. housing 92. The cylinder 88 is screw threaded to the forward end of the cylindrical spacer 83a and has its rear end 93 contracted to tit about and guide the piston rod 86. A piston rod guide 94 is screw threaded into the forward end of the cylinder 88. Recoil type oil is placed in the cylinder 88 between the piston 89 and its closed end 93. The piston 89 is slightly smaller in diameter than the bore of-its cylinder to permit the passage of oil when placed under pressure during reciprocatioh of'the buffer assembly. When the expanding gas enters the lcylinder 83 and drives the piston 84 and piston rods 85 and 86rearwardly, the buffer spring 91 expands at which time the oil in thecy'linder 88 'is' forced to pass between 'the-cylinder wall and piston and comes t0' rest l infront of the cylinder. The return movement of the piston will be buffed by the slow passage of oil to the other side thereof.

Indexing slide 68 is mounted for reciprocation in a forward and rearward direction in guideways 69, Figs. 5 and 6, within the receiver and adjacent the sprocket assembly. The upper surface of the indexing slide is formed as the surface of a cylinder of about 90 angular extent and with its axis coincident with the axis A of shaft 24 and is slotted to receive and guide the rollers 71, 71a, 71b, and 71c on the sprocket wheel 29. When the gun is in battery position the two lowermost rollers are positioned in the rear ends of longitudinal straight slots 95 and 96, as can be seen by reference to Figure 13. When the slide is driven rearwardly by the piston 84 and piston rod 85 the rollers 71 and 71a are guided by the slots 95 and 96 to a position at the front end of the slide. During this step in the indexing cycle the sprocket assembly is held against rotary movement and the dwell, hereinbefore referred to, is accomplished. Near the forward end of the slots 95 and 96, steps 95' and 96' respectively, are formed to prevent the rollers from returning to their respective slots on forward movement of the indexing slide. The spring elements 74 in the sprocket wheel 29 urge the stub shafts and rollers outwardly to the lower level of their respective slots for this purpose and in a manner obvious from comparison of Figs. 6 and 12. The forward stroke of the slide 63 is the driving stroke which rotates the sprocket assembly 90". A sinusoidal cam path is provided by a slot 97 inslide 68, Fig. 13, which communicates with the for ward end of slot 95 and the rearward end of slot 96, so that during this forward stroke the roller 71 isforced tofollow the slot to the position formerly occupied by the roller 71a. The roller 71a is rotated away from'the slot 96 through the cutout portion 96b. A ste'p 97l is formed at the junction of the slots 96 and 97 to keep the roller 71a in its slot 96. lt will be understood that the steps 95 and 97 are formed by the lesser depth, respectively, of slot 95 at its intersection with slot 97 and of 97 at its intersection with slot 96.

A breech closing mechanism in the form of a colar 99 (see Fig. 9) is slidably mounted on the rear end of the barrel 13 and closes the gap between the breech end of the barrel and the forward end of the casing of round R. An internal circumferential beveled face 100 on the rear end of the collar 99 engages a complementally beveled external circumferential face 101 on the forward end of the sleeve 45 to move the round rearward to insure contact between the primer 48 and the firing pin assembly 49 and also to serve to align the case with-the barrel, when the faces are pressed into contact. A copper ring 45b is mounted for limited axial translation witnin a bore in the forward end of sleeve 45. The inner periphery of the ring is formed as the'su'rfaces of two frusto-conical surfaces to define a circular ridge of slightly lesser diameter than the rotating band 46a of the rocket. As the rocket moves forwardly in its case 42, the rotating band contacts the ring 45b and drives it forwardly into contact with the barrel 13. The rising gas pressure acts on the internal and rear surfaces 0f n'ng 45b thereby holding the ring tightly against the rear surface of the barrel and at the same time expanding the ring against its seat in sleeve 45 to effect additional sealing action against loss of pressure. Each sealing .ring is ejected with its cartridge after tiring. Movement of the collar is effected by means of a lever 102, forked at its upper end as indicated at 104, Figure 9 and rotatable on a fulcrum element 103 intermediate its length, and having its upper forked ends 104 positioned in seats formed on opposite sides of the collar 99 for translation of motion thereto. The opposite end of the ,lever terminates in a rounded head 104a which is seated zin Aa socket 105 -in a. sliding block 106. Angle bars 107, 1Figure5, secured to a` bottom plate of the receiver guide the block for straight line movement. A link 108, best shown upon Figure 9, is secured by a pivot element 109 to the block and to a bell crank 110 by the pivot 'element 111. Referring more particularly to Figure 14, the bell crank is secured to a bracket 112 by a pivot element 113 and carries a roller 114 on its free end. A cam groove 115 is formed on the bottom of the indexing slide 68, Figure 5, and receives the roller 114 for reciprocating the breech closing collar in timed relation to the indexing cycle. The cam groove 115 extends throughout the length of the indexing slide and has an offset portion 116 at its rear end. See Figure 13. At the beginning of a tiring cycle the round is fired and the indexing slide is forced back. The rollers 71 and 71a ride in the straight slots 95 and 96 and hold the sprockets and the round in the firing position during the rearward movement of the slide. At the beginning of this rearward movement the roller 114 is guided from the olset portion 116, into the straight portion 115 of the cam groove, and by means of the bell. crank and linkage the lever 102 forces the collar 99 forward to release the tired round and remain out of the path of the incoming round. During the forward stroke of the inde ing slide the breech closing colrar 99 remains in a forward position until the roller 114 is returned to the offset portion 116 of the cam groove' 115. As hereinbefore stated, the forward stroke of the indexing slide causes the sprockets to rotate and thus index a new round into firing position after which the aligning collar is moved rearvviardly into contact with the sleeve of the new roun lInAorder to permit free movement of the round through the launcher, a clearance is vprovided between the overall length of the round and the tiring pin ange 158 and the rear face of the barrel. In order to compensate for manufacturing tolerances in the overall length of various rounds a thrust compensating assembly 1.17 is xed in the support 6 to carry the fulcrum element 103 of lever 102.

A plunger 11'8 having a head 119 is slidable in a cylinder 120. Spring washers or other suitable means 121 urge the piston and piston head rearwardly. A plunger frod 122 extends forwardly from the plunger and passes through a hole in the cylinder head. A nut 123 is screw threaded on the end of plunger rod 122 and provides the means for adjusting the position of the fulcrum element 103 of the lever 102.

Detents 124 and 125, Figures 2, 4 and 5, slidably mounted on the upper guide rails 57 and 58 respectively', hold the round in position to be picked up by the sprocket assembly after the round has been fed into such position. Each detent is slidably mounted on an arcuate plate 126, for movement in an arcuate path about the axis A. Each plate is secured to its respective guide rail. As each round enters the receiver it engages the cam faces 127 of the detents and cams them upwardly in the aforesaid arcuate path against the downward urge exerted by spring pressed plungers 128 which are housed in cylinders 129. The limit of downward movement of the detents is determined by fingers 130 of the detents, which engage an angle bar 131, connecting the rails 57 and 58 thereby stops further movementof the detents in the downward direction. l

Secured to the receiver by screws or otherwise is a bracket 132, Figure 6, which carries a sear 1 33 rotatable on a pivot element 134 parallel with axis A. The sear has an upstanding arm 135 anda horizontal arm 136'which engages a notch 137 on the indexing .slide 68 and holds `the slide in its rearward position when the last round in the magazine is fired. A spring'pressed plunger 138 carried in a casing 139 fixed to bracket 132 tends to thrust the arm toward the incoming rounds but recedes -under pressure of the round to hold the arm 136 out of from inspection -of and charger assemblies are connecte'd to the indexing slide to return it to battery position. As'the assemblies are identical a description of one will Sguiee for both. Referring to Figures l and 10, a front wall 140 of the receiver 5 has secured thereto as by means of screws 141 a housing 142 to which a guide tube 143 is secured as at`144. A rod 145 is positioned axially of the tube 143 and is guided for axial reciprocation by a nut 146 whichis serrated at its outer edges to permit the free passage of air, and by an opening in the support 6. Encircling the rod 145 is a driving or return spring 147 which is confined between the support 6 and the nut 146. The rod 145 extends rearwardly through the support '6 and is secured to the indexing slide 68 as shown at 148 in Figure 10. The forward end of the guide tube 143 extends beyond the nut 146 to provide room for a free piston 149. A cap 150 seals the end of guide tube and is bored and screw-threaded centrally to receive a fluid pressure conduit 154 which is connected to a fluid pressure source, not shown. It is apparent that when pressure enters the cylinder 143, the piston 149 will be driven rearwardly into contact with the nut 146 and consequently the rod 145 will force the indexing slide rear wardly. A buffer 151, Figures l and 4, of any desired type and material is secured in theback plate 50, to absob the impact of the rearward motion of the indexing sli e.

The operation of the gun is as follows:

Fluid pressure is admitted to the feed mechanism and a round R, in the'feed mechanism, is forced into engagement with the sprocket assembly. The sear is lifted by contact of thevincoming round with the arm 135. AWhen fluid pressure .is admitted to the charger assemblies, through' tubes 154, the indexing slide is forced rearwardly, compressing the drive springs 147. Exhausting the charger assemblies causes the slide to move forward rotating the sprocket assembly 90 and sliding the aligning collar 99 into contact with the front end of the round. The last 25 of movement of the sprocket assembly is decelerated by the cam surfaces 61 and'62 of the brake mechanism due to engagement between the sloping surfaces of the cams and the resulting rearward movement of sleeve 59 against the thrust of springs 65. The firing circuit is closed by an external switch, not shown, and the round is fired. Firing continues as long as the switch is closed. If the magazine is exhausted or a round fails to get past the detents 124 and 125 the arm 136 of the sear will drop into the notch 137 of the indexing slide and stop operation of the gun.

While we have disclosed a form of the invention presently preferred by us, various changes and modifications will occur to those skilled in the art after a study of the present disclosure. Hence the disclosure is to be taken in an illustrative rather than a limiting sense; and it is our desire and intention to reserve all modificationsfalling within the scope of the subjoined claims.

Having now fully disclosed the invention, claim and desire to secure by Letters Patent is:

l. In a gun having a barrel, a cylinder having a port in communication with said barrel to admit fluid pressure from the barrelinto said cylinder, means operated by fluid pressure in said cylinder for feeding rounds successively into position for firing. said means including a sprocket wheel to receive and advance the successive rounds, a brake mechanism disposed coaxially with and responsive to the rotation celerating said wheel in position for firing a round therein from said barrel comprising a slidable member having a first plurality of forwardly facing cam surfaces, a second plurality of rearwardly facing cam surfaces integral to the what we rearward end of said sprocket wheel, a spring means normally urging said slidable member in a forward direction. whereby said first and said second cam surfaces are maintained in meshed r'elation, and a cam slide coacting with said sprocket wheel for rotating said sprocket by and in response to actuation of said slide.

of said sprocket wheel for de- 2. In a gun having a frame, a barrel, a cylinder having a port in communication with said barrel to admit fluid pressure from the barrel into said cylinder, piston lmeans reciprocable in said cylinder in response to fluid pressure therein, brackets carried by said frame, a shaft iourna'led in said brackets and disposed parallel to and spaced below the longitudinal axis of said barrel, a sprocket wheel-rotatably mounted on said shaft to receive a plurality of rounds and to advance the same for successive firing from said barrel in response to rotation of said wheel, a cam, means mounting said cam for reciprocation axially-of said barrel, means reciprocating said cam by and in response to actuation of said piston, means rotating said w'heel'by and in response to reciprocation of said cam, and braking means for said wheel mounted on said shaft responsive to rotation thereof to decelerate said wheel into firing position comprising a sleeve encircling said shaft and mounted for axial movement only in one of said brackets, said sleeve defining at its forward end an enlarged portion having a plurality of forwardly facing cam surfaces, an insert integral on the rearward end of said sprocket wheel, said insert defining a plurality of rearwardly facing cam surfaces similar to said cam surfaces on said sleeve Yand compression spring means mounted on said shaft normally biasing said sleeve in a forward direction whereby said cam surfaces on said sleeve are in mesh with said cam surfaces on said insert.

3. In a frame, a gun having a barrel, a cylinder having a port in communication with said barrel to admit 'fluid pressure from the propellant of a projectile launched from said barrel into said cylinder, brackets carried b y said frame, a shaft fixed in said brackets and disposed parallel to and spaced below the longitudinal axis of said barrel, piston means reciprocable in said cylinderin response to fluid pressure therein, a sprocket wheel vassembly rotatably mounted on said shaft and formed to receive a plurality of rounds and to advance the same in succession into alignment with said barrel for firing therefrom in response to rotation of said assembly, a cam, means mounting said cam for reciprocation axially of said barrel, said cam responding to action of said piston for movement in one direction, recuperator means connected to said cam for movement in the opposite direction, means rotating said assembly by and in response to reciprocation of said cam and holding said assembly during a dwell in the firing cycle, and means braking the movement of said assembly toward the end of each indexing movement comprising a tubular sleeve defining an integral enlarged forward portion having forwardly facing cam surfaces thereon, said sleeve being keyed against rotation in one of said brackets and to slide axially therein, an vinsert'integral to the rearward face of said sprocket wheel assembly defining rearwardly facing cam surfaces adapted to mesh with said forwardly facing cam surfaces on said sleeve, a first washer slidably mounted on said shaft and adapted to abut the rearward end of said sleeve, a second washer on said shaft secured against rearward movement thereon and a plurality of Belleville springs encircling said shaft and disposed between said washers, said springs normally biasing said sleeve forwardly to maintain said cam surfaces on said sleeve and said insert in meshe'd relation, said means being responsive to the rotation of said assembly.

4. An automatic gun for firing rocket-cartridge type rounds having a frame. a barrel, a back plate secured to said frame and spaced from the breech end of said barrel a distance substantially equal to the length of 'the round, a cylinder having a port in communication "th said barrel to admit fluid pressure from the barrel into said cvlinder. means operated by fluid pressure in said cylinder for feeding rounds successively into axial alignment with said barreland abutting said back plate, said means including a sprocket wheel to receive and advance 'the suece'ssive rounds', said wheel having radially extending rollers, a first cam for translating motion to said radiallyfextending rollers for rotating said wheel by and in response to actuation of said first cam, a collar reciprocable on said barrel and abutting the front end of said round to accurately position said round, a second cam for translating motion to said collar, said means comprising a pivoted bellcrank lever, a roller on one arm thereof slidable in said second cam, a block having a socket therein, means mounting said block for reciprocation axially of said barrel, a link connecting said block and said bellcrank, a resiliently cushioned support having a pivot element, a lever mounted on said pivot element intermediate its ends, one end engaging the socket in said block the other end terminating in a yoke to embrace and reciprocate said collar in response to actuation of said second cam, and a clutch mechanism for holding said wheel in position during tiring of the round and reciprocation of said collar.

5. In a gun having a frame, including a back plate, a barrel, a cylinder having a port in communication with said barrel to admit liuid pressure from the barrel into said cylinder, piston means reciprocable in said cylinder in response to liuid pressure therein, a sprocket wheel rotatably mounted to receive a plurality of rounds and to advance the same for successive tiring from said barrel in response to rotation of said wheel, a recprocable indexing slide having cam grooves in its surface, means on said wheel engageable in said cam grooves for rotating said wheel in response to reciprocation of said slide, a resiliently held tiring pin mounted in said back plate in alignment with said barrel, a tiring switch comprising a pair of spring pressed contacts secured to said frame and a circuit closing bar secured to said indexing slide and bridging said spring pressed contacts when said slide is in forward position, and means for conducting voltage to said firing pin.

6. In a gun having a receiver, a cover for said receiver, a barrel, a cylinder in uid communication with said barrel, liuid pressure responsive piston means reciprocable in said cylinder, axially aligned spaced sprocket wheels rotatably mounted in said receiver for receiving a pluralty of rounds and to advance same for successive tiring from said barrel in response to rotation from said wheel, a reciprocal indexing slide having cam grooves in its surface, means carried by said wheel for translating movement to said wheel, means for holding said rounds in seated position in their respective recesses in said sprocket wheels as they are picked up and rotated towards iiring position comprising, guide rails secured to the under side of said cover, each said rail having an arcuate lower edge spaced radially from and equiangular to the outer periphery of each said sprocket wheel, an arcuate plate secured to one side of each said rail, a spring loaded detent slidably mounted on each said arcuate plate, its lower edge forming a continuous equiangular arc with said arcuate edge on each said plate, there being a cam surface at one edge of each said detent adapted to engage an incoming round entering said receiver and lift said detent to permit said round to enter its respective recess in said sprocket wheel, there being an integral finger on each said detent limiting its downward movement and a pivoted sear delining an upstanding and a horizontal arm, said scar rotating in a counterclockwise direction upon engagement with a round in said sprocket wheel to lift said horizontal arm from engagement with said slide to permit reciprocal movement thereof and to rotate in a clockwise direction when said sprocket wheel is empty to bring said horizontal arm into engagement with said slide and stop operation of said gun.

References Cited in the iile of this patent UNITED STATES PATENTS 564,043 Benet et al. July 14, 1896 2,450,929 Ashworth et al. Oct. 12, 1948 2,464,920 Carter Mar. 22, 1949 2,575,368 Thomsen Nov. 20, 1951 2,638,339 Taylor May 12, 1953 FOREIGN PATENTS 125,126 Great Britain Apr. 17, 1919 589,177 Great Britain June 13, 1947 639,766 Great Britain Iuly 5, 1950 687,826 Great Britain Feb. 18, 1953 288,467 Switzerland May 16, 1953 1,040,335 France May 20, 1953

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