OCt. 15, 1946. J, C, CANTLEY ErAL ZÁÜQÃSÈ AUTOMATIC FIREARM Filed May 14, 1945 1,. 2 sheets-sheet -1 Oct. 15, 1946. ,1_ C, CANTLEY ET AL 2,409,251 AUTOMAT IC FIREARM Filed May 14, 1945 2 Sheets-Sheet 2 ,ist Patented Get. 15, 1946 U 2,409,251 AUTOMATIC FIREARM Joseph C. Cantley, Beverly, and Arthur F. Pym, deceased, late of Topsiield, Mass., ‘by George H. Heys, administrator, Swampscott, Mass., as , signers to United Shoe Machinery Corporation, Flemington, N. J., a corporation of New Jersey ` Application May 14, 1945, Serial No. 593,640 8 Claims. (Cl. 89-3) 2 This invention relates to firearms and more particularly to mechanism for insuring an ap proximately constant rate of ñrein automatic guns. iired at its normal rate, serves as a basis Yfor computing the velocity-curve of the power-driven rack, It has been found that the rate of fire of guns installed in airplanes, for example, is dependent to a considerable extent upon the wind pres sures and temperatures to which the guns are subjected, the greater the wind pressure and/or the lower the temperature, the slower the cyclic rate of fire of the guns. It is desirable at all times to maintain as nearly as practicable the normal iiring rate of the gun, having in con sideration, for example, the need for maximum ñre power and the most efûcient operation oi mechanism which automatically feeds ammuni tion to the gun. It is an object ci' the present invention to pro vide a Simple, efïective device for maintaining a sustained ñring rate in automatic guns oper ‘ ` 4 When the power-driven and the tube-oper ' ated racks are reciprocated at the same speed f in opposite directions along their respective guideways, the pinion, which is rotatably mount ed upon the valve operating slide, rotates but does not cause the slide to move along its guide way. When, however, the vtube-opera'tedrack is moved slower than the power-driven rack, the slide is moved along its guideway bythe pinion, causing the valve to reduce the oppos ing eiiect of the resistor unit, thereby enabling the tube tc accelerate to its normal speed for its particular displacement from battery posi tion. When the tube speeds up suiîiciently to cause the tube-operated rack to'move faster than the power-driven rack, the pinion carrying slide is moved in an opposite direction along ating under adverse conditions. With the above object in View and in accordance with a feature of the present invention, there is provided, in an automatic gun, a power-driven member having a substantially uniform velocity-curve, a member its guideway, causing the valve partiallyto close, operative in response to recoil and counter-recoil movement 0f parts ofthe gun, a resistor unit, battery position. ' The valve is'so operated that comprising fluid and a housing therefor, for op posing the recoil and counter-recoil movement with the result that the opposing effect of the resistor unit is increased Vto such an extent that the tube slows down approximately to its nor mal speed for that particular displacement from the speed of the tube-operated rack will at any particular moment be substantially equal to the v speed of the power-drìvenrack, thereby insur of said parts of the gun, a valve for controlling 30 ing that the cyclic rate of the gun shall be ap proximately constant irrespective of the condi; liow or fluid in said housing, and mechanism re sponsive to differences in speed between the power-driven and the gun-operated members for controlling said valve to cause the velocity curve of the gun-operated member to approxi mate the velocity-curve of the power-driven member. ` The power-driven member and the gun-oper ated member, which is operatively connected to the tube or barrel of the gun, have the form of .A racks which reciprocate in directions opposite to each other along spaced parallel guideways respectively, the teeth of one of the racks being spaced from and in opposed relation to the teeth oi the other rack. Opposing the recoil and counter-recoil movement of the tube and other parts of the gun is said resistor unit, the re tions under which it is operated. ' A The various features of the invention will' be understood and appreciated from the following detailed description read in connection with the accompanying drawings, inwhich ' ' Fig. 1 is a side view, partly broken away and partly in section on line I-I of Fig. 3, Showing the illustrated device incorporated in a 37 mm. gun 'of the general type disclosed in United States Letters Patent No. 1,525,055, grantedV Feb ruary 3, 1925, on an application filed in the name of John M. Browning. ' Fig. 2 is a side view similar to Fig. l, partly in section on line II-II of Fig. 3; Figs. 3 and 4 are sections on lines III-v-III, lV-IV of Figs. 2 and l, respectively; Figs. 5 and 6 are sections on lines V-V and sistance of which varies in accordance with the setting of said Valve. In meshing relation with ‘JI-_VL respectively, of Fig. 4; and Fig. '.7 is a timeedisplacement chart of recoiling the teeth of the racks is a pinion rotatably 50 mounted upon a slide which is movable in a parts of the gun. guideway arranged parallel to the guideways The illustrative 37 mm. gun comprises a barrel or tube 2t (Fi-gs. l, 2 and 3) an enlarged breech portion of which is slidingly mounted for recoil and counter-recoil movement in a cylindrical of the above-mentioned racks and is operatively connected to the valve. The velocity-curve of the tube-operated rack, when the gun is being ' 2,409,251 3 4 bore 22 (Figs. 2 and 3) of a trunnion block 2li, the tube being further supported >for sliding housing 38, together with the recuperator spring movement in said bore by a brass bushing 25 (Figs. 1 and 2) secured to the forward end of the trunnion block. Secured by screws 2S to the trunnion block 2li are trunnions 35 which are swiveled upon a cradle (not shown) suitably mounted for rotation about a vertical axis for moving the gun in azimuth. Since the 37 mm. gun illustrated herein is of the type used exten 10 and the oil in the front chamber 54 of the hous sively in this and other countries and is well known to those skilled in the ordnance art, only such parts of the gun as are `necessary :in dis su, opposing recoil movement of the tube 2G, ing opposing the counter-recoil movement of the tube, which recoil movement is eiîected by the action of the recuperator spring. It is desirable that the gun shall fire at its normal cyclic rate (approximately 150 shots per .minute) even under adverse conditions, such, -for example, as high wind load and extremely low temperatures. Moreover, it is further de sirable that when the gun has an automatic ammunition feed, such, for example, as dis closed 'in an application for Letters Patent of closing the illustrative device need Ábe described herein. 15 the United States Serial No. 637,236, filed De cember 26, 1945, in the names of Ernest W. The tube 20, together with `a 'tube extension 3%.? Stacey and Frank W. Reinhold, the regular nr (Fig. 2) threaded onto the rear end of the tube, ing rate shall be substantially maintained in is moved rearward approximately 9% inches order that the mechanism which feeds the shells during recoil along the bore 22 of the trunnion block 2li from its battery position, shown in full 20 to and chambers said shells in the gun shall roperate most effectively. lines Eig. 2, the tube and its extension being re ‘When the gun is being ñred under ordinary turned to battery position from its fully recoiled conditions at its normal cyclic rate, the velocity position, shown in dash lines, by a recuperator curves of the tube 2€) and the tube extension or resistor unit 315. .Formed integral with and >extending downward from the trunnion block 2t 25 3?. on the one hand and .a lock frame (not is a support 35 in a bore of which is secured a shown) on the other hand are approximately two-part recuperator housing 3S containing oil. Secured to the housing 38 is a bushing ¿25 (Figs. 1, 4 and 5) provided with three circumferentially Vwriifcrrn or constant, such curves being readily computed from the 37 mm. gun time-displace ment chart such as illustrated in Fig. '7. As will appear later, when the illustrative gun .spaced elongated oil by-pass openings (i2 (Figs. 1 land 4), the purpose of which will be explained later. Slidably >mounted in the bushing ¿it is a piston Ml (Figs. 1 and 5) threaded onto the for ward end of a Vrod ¿i5 which passes through regis tering openings llß, 55 (Fig. 2) formed respec tively in a rear closure cap `52' threaded .into the recuperator housing 38 and in a depending por tion of the tube extension 32. 'I'he rod 46 is se cured to the tube extension 32 by a nut 54 which is threaded onto the rear end of the rod, iits in a hole in the tube extension, andis turned to draw a collar 55 >of the rod into clamped engage -ment withsaid extension. The forward end of the recuperator housing 3,3 is closed by a cap 58 (Figs. 1 and 5) threaded >into the housing. Surrounding the rod e5 and >interposed between the piston ¿il and the rear closure cap 52 is a spring 59 which is com pressed during the recoil movement of the tube -20 _and the tube extension 32 and serves to move - said tube, together with its extension, back to battery position. The piston »til is moved length wise of the housing 38 from its full-line posi tion (Fig. 1,) to its dash-.line position and >back again, oil being transferred Yfrom one of the chambers 62 (Figs. 1, >2 and 5), 64 (Figs. l and 5) at the rear and front, respectively, of the piston, to the other through the by-pass open ings 42 (Figs. 1 and 4) in the bushing 49. The rear closure cap 52 (Fig. 2) of the recuperator housing 38 is provided with a suitable stuñing box >65 to insure against oil seeping from the rear chamber E2 between the cap and the pis ton rod 46. It will be notedV (Fig. l) that the oil by-pass openings 42 extend well forward of a front working face >68 of the piston 4d -in its full-line battery position and rearward approximately to a rear working face 'm of the piston in its recoiled dash-line position. The bushing open ings 42, which are considerably smaller in cross section than are corresponding openings in the bushing of the 37 mm. gun now in common use, Iserve to by-pass oil around the piston (it, the oil in the rear chamber 52 of the recuperator hres at a subnormal rate because of adverse conditions, resistance operating against recoil ing and counter-recoiling movement of the tube 25, together with its extension, is automatically decreased in accordance with the reduction in speed of said parts, with the result that lsaid parts of the gun almost immediately acquire a speed slightly greater than the normal speed of such parts for that particular portion of their cycle. When this occurs, the resistance oper ating against the recoiling and counter-recoil ing parts of the gun immediately increases and accordingly the speed of such parts is reduced slightly below their normal speed for that par ticular portion of the cycle. When operating under constantly changing wind and tempera ture conditions, the resistance operating against the recoiling and oounter-recoiling parts of the gun is continuously varied through the provision of mechanism which is hereinafter described and is constructed and arranged to insure that the velocity-curves of said ,parts of the gun re main approximately uniform and are approxi mately the same as the Velocity-curves of said parts when the gun is operating under normal conditions. With such a control, it will be ap parent that the gun maintains a substantially constant cyclic rate regardless of the conditions under which it is fired. With a View to varying the resistance operating .against the recoiling and counter-recalling parts o1' the gun, there is provided a block ‘l2 (Figs. 1, e, 5 and 6) having a pair of oil passages ‘i4 (Figs. 4 and 5), 75 (Figs. l and V6) the rear ends of which are in registration with openings 78 (Fig. 5) , ‘80 (Fig. 1), respectively, in the recuperator housing 38 and aiiord access to the rear oil chamber 62. The forward ends of the passages "M, 'I6 are in registration with alined openings 82 (Fig. 5), 84 (Fig. 1), respectively, which are formed in the re cuperator housing 38 and the bushing 40 and alTord access to the front oil chamber 64. The block 'l2 is held in forced engagement with the bottom of the recuperator housing 33 by a cylin drical portion 8S (Figs. 1 Vand 4) of the block .2,409,251 5 which ñts on and is secured to the housing. As `above stated, the passages 14, 16, which may be said to include the openings 18, 80 and the open ings-82, 84, respectively, extend forward to posi tions just in advance of the piston 44 in its full line battery position (Fig. 1) and rearward to `positions just behind the piston in its recoiled position- (shown in dash lines, Fig. 1). Mounted in the passages 14, 16 are check valves 88, 90, 6 rack |20 (Figs. land 3) .mounted for forward'and rearward reciprocation in a guideway |22 of a depending portion`|24 of the trunnion block' 24. Itwill benotedY upon examining the Vtime dis placement chart shown in Fig. 7 that the tube 20 and the tube> extension 32 of the above-iden tified 37 mm. "gun, arrive at a battery position ¿and remain there 'at rest for a short period, rep resented by reference numeral |28, while the lock respectively, the valve 80 preventing flow ofoil 10 frameV (not shown) of the gun moves" forward undei` spring action to its battery position, the in the passage 1E from the rear oil chamber 62 sh'ell‘during such rest period beingÍ chambered to the front oil chamber 64 of the recuperator and the breech block (not shown) being locked in housing 38 and the valve 88 preventing flow of its battery position._ Accordingly, the vcarnway oil in the passage 14 from the front to the rear |08 vis designed to cause the lever ||2 to vremain oil chamber. at rest during the rest period of the tube 120, the Mounted for rotation in the block 12 is a valve follower H0 at such time being in engagement 92 (Figs. 4, 5 and 6) having ports 84, 96 which with a concentric portion |28 (Fig. 1) of the cam may be moved into registration with the passages » Way. 14, 16, respectively. In order to vary the ilow of Slidingly mounted in a rectilinear guideway oil in directions 95 (Fig' 5), 91 (Fig. 6) through |30 (Figs. 2 and 3) of the depending portion |24 the passages 14, 15, respectively, for the purpose of the trunnion block 24 is a rack |32 the vrear of controlling the cyclic rate of the gun ñring end of which has secured to it a lug |34 (Figs. 1 under adverse conditions, the valve 92 is actuated and 2) provided With a transverse slot |36 (Fig. through mechanism which will now be described. When the valve 82 is in the position shown in 25 2) in which nts a depending ilange |38 ofthe tube extension 32. Rotatably mounted in the de Figs. 5 and 6, its ports 94, 06 are so positioned pending portion |24 of the trunnion block 24 is that they restrict to a considerable extent the a shaft |40 (Figs. 1,'2 and 3) to which are se flow of oil through the passages 14, 15, the com cured large and small pinions |42 (Figs. 2 and 3), bined ilow of oil through said ports thus posi tioned and through the openings 42 in the recu 30 |44 (Figs. 1 and 3),-respectively, the pinion |42 being operatively connected to the rack |32 and perator bushing 40 restricting the flow of oil the pinion |44 being operatively connected to from one chamber 62, B4 to the other approxi mately to the same extent that oil is restricted in larger but corresponding recuperator bushing Yopenings alone of the 37 mm. gun now in use. - a rack |46 slidingly mounted in a rectilinear guideway |48 which is formed in said ~depending portion |24. The pinion |42>has a diameter approximately three times that of thepinion |44 and accordingly the travel of the rack in its guideway |48 is one-third of the recoil and coun Accordingly, when the gun is operating under normal conditions, the valve S2 is positioned ap proximately as illustrated in Figs. 5 and 6, the ter-recoil travel of the tube 20 and is also in a iiow of oil in the passages 14, 1B being somewhat reverse direction to the direction of travel of 40 restricted. Since the unitary valve 92 comprises said tube. ’ ` ports 94, 96 for regulating the iiow of oil through Slidingly mounted in alined guideways' |50, |52 the passages 14, 15, respectively, such valve may i (Fig. 1) of the block 12 and the depending por be considered as constituting a pair of valves and tion` |24 ofthe trunnion 'block 24 is a rack `or be referred to as such. rack slide |54 (Figs. 1 and 4) upon the rear’bi In order that the velocity-curve of the tube furcated end of which freely rotates a pinion 20, and accordingly the recoil portion of the ve |56 (Fig.v l) constructed and arranged to mesh locity-curve of the lock frame of the gun, shall be with teeth of racks |20, |46. The teeth of the approximately uniform and similar to the veloc rack slide |54 mesh with teeth of a pinion |58 ity-curves of corresponding parts of the gun iired secured to the rotary valve 92. at a cyclic rate of 150 rounds per minute, the V1t will be apparent that when the racks |20, valve 92 is automatically rotated, if necessary. |45 move at the same speedV in opposite direc Such rotation of the valve is effected through tions lalong their parallel guideways |22, |48, the mechanism which will be described presently and vpinion |56 Will rotate freely 'upon the rack slide which operates during the recoil and counter-re |54 but will not impart-to the slide |54 a trans coil movement of the parts of the gun in order latory movement along its guideways |50, |52 to allow oil in greater or less quantities to flow whichare parallel to the guideways |22, |48. through the passages 14, 18 in directions 95 (Fig. Should the tube-operated rack |46 slow down 5), 97 (Figs. 1 and 6), respectively, with the re and thus move slower than the rack |20, which sult that the resistance opposing the recoil and may be referred to as a control or speed regulat counter-recoil movement of the tube is varied ing rack, during the recoil movement of the tube in accordance with changes in the setting of the 20, for example, the slide |54 will move to the valve. left, as viewed in Fig. 1, causing the valve 92 Mounted for rotation at a constant predeter to rotate clockwise, as viewed in Fig. 5, with the mined speed in a bracket 98 (Fig. 3) secured to result that resistance to the flow of oil from 65 the trunnion block 24 is a shaft 100 which is op chamber 82 to chamber 64 of the housing 38 is eratively connected through a suitable clutch |02 decreased. The effect of such action is to cause to a shaft |04 also rotatably mounted in the the recuperator piston 44 to offer less resistance bracket. Secured to the shaft |04 is a cam |06 to the recoil movement of the tube 20. When this (Figs. 1 and 3) having a camway |08 (Fig. l) in occurs, the tube 20 immediately speeds up until which fits a follower ||0 rotatably mounted upon it causes the rack |48 to move faster than the a lever ||2 (Figs. l, 2 and 3). The lever i|2 is rack |20, with the result that the rack slide |54 swiveled at its upper end upon a fulcrum pin | i 4 secured to the trunnion block 24 and has at its >lower end an elongated slot ||6 (Fig. 1) for re ceiving a pin ||8 secured to the rear end of a moves to the right, as viewed in Fig. 5, causing the valve 92 to be rotated counterclockwise and thereby restricting the now of oil in the direction :2,409,251 7 '£5 in the passage 154 and causing the recuperator piston ¿le to oirer increased resistance to there coil .movement of the tube 2U. ‘ Vresistor unit, comprising fluid and 'a housing therefor, 'for opposing the recoil -and counter recoil movement of said parts of the gun, a valve If., during its ‘counter-.recoil movement, the vfor controlling flow of ñuid in said housing, and tube 2€) vfails to maintain its desired velocity Ul mechanism responsive to differences'in speed be curve, the rack |46 slows down with relation to tween rthe power-driven and thev gun-operated the rack |20, causing the rack slide |54 to move members for controlling said Valve to cause the to the right, as viewed in Fig. 1. Such action velocity-curve of the gun-operated member to causes the valve 92 to move counterclockwise, as approximate the velocity-curve of the 'power viewed in Fig. 6, and accordingly to offer less re 10 driven member. ' sistance than previously to the flow of cil in di 3. .In an automatic gun, a member movable in rection 91 through the passage ‘16. As the resist response to vrecoil and counter-recoil movement ance to counter-recoil movement of the tube 20 oi parts of the gun, a power-driven member hav Vi's reduced the tube 26 speeds up and attains a ing a substantially uniform velocity-curve, means velocity suñicient to cause the rack |46 to lmove for resisting recoil and counter-recoil movement faster than the rack k|29 and thus to move the of said parts of the gun, said means comprising rack Slide i 54 to the left,`as'viewed'in Fig. 1, with iiuid, a housing therefor, and a valve for restrict the result that the valve 92 is rotated clockwise, ing now of fluid in the housing to control the as viewed in Fig. 6, and offers increased resist rate of recoil and counter-recoil movement of ance to the flow of oil through the passage 16. said parts of the gun, and valve operating mech When this occurs the recuperator piston 44 of anism which is responsive to differences in speed fers increased resistance to the rtube 2B which between the Gun-driven member and the power tends to slow down to its 'normal speed for its driven member and which is constructed and particular displacement from battery position. arranged to operate the valve and to insure that The construction of the above-described op the cyclic rate of the gun shall be approximately erating parts is such that the device is sensitive equal to that of the power-driven member. to slight variations in speed between the racks fi. In an automatic gun, a member movable >in i253, |136 and responds rapidly to said variations, -response to movement of recoiling and counter the valve 92 moving almost continuously back recoiling parts of the gun, a control member, and forth 'to a slight extent when continuously 30 means for moving the control member in a su'b varying operating’conditions are encountered. stantially uniform velocity-curve, a valve, a fluid The ‘shaft le!! isV driven by a constant speed containing resistor unit for controlling the rate motor (notshown) for example. When the gun of recoil and counter-recoil movement of said is being-fired automatically, the clutch |92 is op parts ci the gun and accordingly the cyclic rate erative to couple the shafts |88, |94 so as to ro of the gun in accordance with the setting of said tate the shaft lef! ata 'fixed speed, a solenoid valve, and means movable in response to differ |59 being continuously energized during such time to hold the clutch in its driving position, shown in Fig. l. . ences in speed between said members for operat ing said valve. ' 5. In an automatic gun, a power-driven mem When single shots are being fired by the gun, 40 ber having a substantially uniform velocity-curve, it is desirable that the rack |20 shall be set a member movable in response to recoil Vand in motion upon pulling the trigger (not shown) counter-recoil movement of parts of the gun, a and ’that upon completion of the cycle of the gun resistor unit for opposing the recoil and counter the rack shall come to rest. The illustrative con recoil movement of said parts of the gun, mech trol is such that when the trigger is pulled a anism for varying ‘the amount of resistance with circuit is closed, causing the solenoid |60 to be whichY said unit opposes the recoil and counter come energized and thus to throw in the clutch recoil movement of the gun, and means respon |112, thereby rotating the cam |65 at a constant sive to differences in speed between the power speed. Upon release of the trigger the above driven member and the recoil and counter-recoil mentioned circuit is opened, but a relay is pro driven member, said means being constructed and vided to keep the solenoid energized until a arranged so te control said mechanism that the switch IâìZ (Fig. 1) is engaged> by a projection velocity-curve of the recoil and counter-recoil |66 on the cam Hit, at which time the solenoid driven member is approximately the same as the is de-energized and the clutch |702 is thrown out, velocity-curve of the power-driven member. the shaft lilli, through the provision of a multiple 3.3 6. In an automatic gun, a piston movable in'op Vplate brake (not shown) associated with> the pcsite directions in response to recoil and coun ~ clutch, coming quickly to and remaining Vat rest ter-recoil movement of one or moreparts of the until the gun is again ñred. 'Y gun, fluid housing means constructed and ar ranged to Vresist movement of said piston in op Having described our invention, what we claim as new and desire to secure by Letters Patent of (SO posite directions, a member responsive to move the United States is: ment oi said one or more parts of the gun, a power-operated member having a velocity-curve l. In an automatic gun, a unit for resisting re coil and counter-recoil movement .of parts of the which is approximately uniform, fluid flow con gun, for varying the amount of resistance trol means for varying resistance operative ‘oiîered 'oy said unit, a movable control member against the piston during recoil and counter-re having a substantially uniform velocity-curve, coil movement of the gun, and mechanism oper a member movable in response to recoil and coun ative in response to differences in speed between ter-recoil movement of one or more of said parts said members for operating said ilow control of the gun, and mechanism operative in response means whereby to vary resistance of fluid in said 'to differences in speed between said members for fluid housing means against said piston. -controlling said means. '7. In an automatic gun, a barrel mounted for 2. lIn an automatic gun, a power-driven mem recoil and counter-recoil movement, a housing ber having a substantially uniform velocity-curve, for ñuid, a piston slidable in the housing in re Va member operative in response to recoil and sponse to movement of said barrel, said piston vcounter-recoil movement of parts of the gun, a having fluid engaging Working faces, passages 2,409,251 10 connecting chambers of the housing which are 1o cated opposite the Working faces respectively of the piston, valves arranged in the respective pas sages, a rack, power-driven means for reciprocat ing said rack in a substantially uniform velocity curve, a rack movable in response to the recoil and counter-recoil movement of the barrel, a freely rotatable pinion which is operatively con nected to both said racks and is also mounted for movement in a translatory path, said pinion being rotated but not moved in said translatory path when the barrel-operated rack moves at the same velocity as and in an opposite direction to the power~driven rack, said pinion being rotated and also moved in said translatory path when the velocity of the barrel-operated rack is dif ferent from that of the power-driven rack, and means responsive to translatory movement of the pinion for varying the setting of the valves. 8. In an automatic gun, a rack driven in a rec tilinear path in response to recoil and counter of the gun, a control rack which is reciprocable in a rectilinear path parallel to the path of re ciprocation of the gun-driven rack and Which moves in a direction opposite to the direction of movement of the gun-driven rack, said control rack having a substantially uniform velocity curve as it moves in said path, a slide, a pinion rotatably mounted upon the slide and positioned between and in meshing relation with the racks, said pinion being rotated but not operative to move said slide When the racks move at the same speed in opposite directions, said pinion being ro tated and operative to move the slide when the gun-driven rack moves at a speed different from that of the control rack, and means operative in response to movement of the slide for causing said valves to open and close in order that the gun-'driven rack shall have a velocity-curve ap proximately the same as that of the control rack, 20 thereby insuring that the gun shall have a sub stantially constant cyclic rate. recoil movement of parts of the gun, a fluid con taining resistor unit for opposing recoil and coun JOSEPH C. CANTLEY. ter-recoil movement of the gun, valves for vary GEORGE H. HEYS. ing the resistance oiîered by said unit to the re 25 Administrator of the Estate of Arthur F. Pym. coil and counter-recoil movement of said parts Deceased.