US2696760A - Recoil compensating device - Google Patents

Description

Dec. 14, 1954 Filed July 13, 1946 C. W. MUSSER RECOIL COMPENSATING DEVICE 2 Sheets-Sheet 1 HIIIII llllll A {I I, 32.12:: l m @uufl :!!!!l N I .v N IL INVENTOR. 0 B- WALTDN MLISSER- ATTEIRNEYE- Dec. 14, 1954 c. w. MUSSER RECOIL COMPENSATING DEVICE Filed July 13, 1946 2 Sheets-Sheet 2 WWW \QM Q 9 W M \NJ \Q Mil 1g 9 MI Ill 53: ouuu 0 i- =oou 2.5.5 3 U II 4631 05:51 m

OP mzmmSOO 460mm .rbozti 463m Bin 4 United States Patent CONIPENSATING DEVICE.

Clarence Walton Musser, Philadelphia, Pa., assignor to the United States of America as represented by the Secretary of War Application July 13, 1946, Serial No. 683,380

4 Claims. (Cl. 89--1;.'Z) (Granted under Title; 35, U..S; Code (1952),.sec. 26,6)

The invention described herein, may. be manufactured and used" by or for the Government for governmental purposes, without. the payment to me of any royalty thereon.

This inventionrelates. to, guns of the. recoillesstype. It hasspecial referenceto'non-recoil guns which-the prior art has. devised to overcome. the forces of rearward reaction that normally result from. combustion of the propellent. powder, in conventional recoiktype guns, which causes discharge of the projectile therefrom.

The recoilless type. Weapon to which this invention has special reference eliminates recoil by expelling powder gases to the rear exterior of the gun under conditionsso controlled that the forwardly acting thrust on the gun thereby imparted neutralizes the, rearwardly acting thrust which is conventionally known to result upon firing a projectile. To better appreciate this invention, it should be understood that under certain circumstances, in particular long usage of the gun, the recoilless character of the guncan be lost and mustbe compensated for if nonrecoil operation is, to be, continued. For example, one possible cause for upsetting the guns recoilless character is the possibility of the conditions under which powder gases are rearwardly emitted gettingout. of control. When this happens. it ispossible, as will be explained below, that, the gun will suffer rearward recoil in ageeoldconventional'manner, or forward recoil in a manner rather peculiar to the recoilless type weapons.

Broadly stated, the object of this invention is to improve the design and extend the usefulness of recoilless guns which incorporate principles of construction and operation first disclosed and claimed inco-pending applications Serial'No. 536,590, filed May 20, 1944, now abandoned, for Recoilless Firearms, Ammunition Therefor, and Ballistic Design Thereof and Serial No. 577,830,

filed February 14., 1945, now Patent 2,472,111, for Recoi-lless Firearmand Ammunition Therefor, both in the names of William}. Kroeger and C. Walton Musser, and application Serial No. 628,647, filedNovember 14, 1945', now Patent 2,444,949, for Recoilless Firearm, :in the. name of C. Walton Musser.

A more specific object of this. invention is to provide improved chamber constructions for recoilless guns'which compensate for therecoil inherent in the operation of a gunand which are adjustable so as completely to eliminate both forward or rearward recoil.

A still further object of this invention is to provide arecoilless gun of increased simplicity, ruggedness and compactness, particularly as to the means for compensatingfor and adjusting to eliminate recoil.

Other and further objects and advantages will be apparent tov those skilled inthe art, or will be readily understood from the annexed drawings and specification to which reference is here made for further exposition of this invention.

In the drawings:

Fig. l is a view inside elevation with parts broken :away in longitudinal vertical cross section.

Fig. 2 isv a transverse cross section online 2-2"0f Fig. l .in the direction of the arrows.

Fig. 3' is a view of the end of the adjusting ring as .seen from lines 3-3 of Fig. 1 when looking in the direction of the arrows.

Fig. 4 is a partial longitudinal cross section online -4...-4offFig. 2 as viewed inthe direction of the arrows.

8 Big. 5, is. adiametrical cross section of the reca l C9 1 2,696,760 Patented Dec. 14, 1954 pensati-ng. ring substantially on line: 5..5- of Fig. 3 with intermediate parts, broken away.

Fig. 6 is; a view of the recoil compensating: ring in side elevation with one of the faces. shifted totheouter side of the r n Fig. 7 is a simplified schematic diagram showing the effect of the recoil compensating ring in reversing-the direction of or neutralizing'a guns recoil.

The embodiment of the recoilless gun which has been selected for illustration in the drawings and description in the specification hereof is made. as. follows 2.

A hollow projectile-directing barrel 11}. has. on its. in: terior rifling 11 to impart a spin or twist. during the flight to the projectile P whose tip is shown in Fig; 1. At the rear of the barrel 10. there is a cartridge-contain: ing or explosion chamber made up of a. frusto-conical hollow chamber portion 12, and a cylindrical hollow chamber portion 13.

Cartridge C, having a perforated case, is plaeedtinrthe chamber 12-13 and is of such size that it is spaced from the, major portion of the walls of the frusto-conical chamber portion 12 and from the walls of the cylindrical chamber portion 13. The rear part of chamber. portion 13 is lined with a ring-shaped reliner 14, which is threaded on its peripheral walls as indicated at 15 by means? of which it is secured to the inner walls; of the chamber portion 13. Through reliner14, pass rearwardly extending vents. 16 which are shown as being'four in number. and of transversely elongated venturi shape. Fig. 4 shows that each of the venturi openings has, intermediate its end, a throat 17 of restricted or reduced crosssectional area.

The central opening through reliner 14 normally is closed by a pivotally mounted breech block (not shown) which abuts against the rear end of the cartridge case C.

On the front face of the. chamber reliner 14, are thread.- edly mounted four, bolts 18, each of which extends axially forward and has, at its opposite end, a head. 19 of larger diameter. The, purpose of these bolts is-.to. support a recoil compensatingring (generally indicated. at 21 in the drawings.) a desired spaced distance axially with respect to the powder charge (not shown)v contained in the cartridge C, for reasons which will be made clear below. To thus space ring 21 there are suppliedaplurality of spacers 20 in the form of tubular or ringshaped washers which are placed on bolts 18. before the bolts are mounted on reliner 14. The-number of these washers 20v which are interposed between the front face of the reliner 14 and the rear face of the recoil compensating ring 21 determine the distance by which the ring 21 is spaced from the, front of the,.reliner:14, and likewise determines. the aforementioned axial spacing with respect to the propellentcharge.

The recoil compensating ring 21. is preferably madenp of two semi-circular ring halves 22 and 23 (see Figs. 3, 5 and 6) which have endportions 24 01? reduceduthick+ ness, so that these end portions overlap, permitting. the two ring halves 22 and 23 to bev joined together. to form a complete ring. This two-piece construction makes it possible to introduce the, ringparts through the openings, at either end of chamber 1213 which are. of smaller diameter than the interior of chamber portion 13. where the ring is to be assembled and mounted crosswise of the chamber as shown. The central opening 25 in the assembled ring 21 is of sufiicient diameter to permit the cartridge case C to pass through it. The ring 21 has such an outside diameter that its perimeter lies against the inner surfaces of the wall ofv the cylindricalchamber portion 13.

The operation of the recoil compensating ring of the present invention can be readily explained by reference to the Fig. 7 simplified schematic diagram. Parts A, B and E of that illustration show an open-breech recoilless type weapon without benefit of the novel recoil compensating ring 21, whereas parts C, D, F and G show the gun as supplemented by the compensating ring.

In A, the gun is shown as having a chamber with a forward opening through the barrel whose diameter is equivalent in size to the rearward opening in the breech endof the gun. Thus, the chamber wall area, being exactly equaLall over, the forward. and. rearwar -manage 3 pressures caused by the burning of the propellent powder will be exactly equal, and no gun recoil will result. (In this and in the other illustrations of Fig. 7, it is assumed that the gas pressures acting in a radial direction from cartridge C exert equal forces at all points on the cylindrical chamber walls so that no movement of the gun on an angle to its longitudinal axis will occur.)

In parts B and E, the balance between forward and rearward-acting pressures is shown disrupted. The former, having a larger breech opening than the opening through the barrel, presents a larger surface at the barrel end of the chamber for the gas pressure to act upon thereby causing a forward-acting thrust or recoil on the gun. The latter, having a smaller breech opening than the opening through the barrel, presents a larger surface at the breech end of the chamber for the gas pressure to act upon, thereby causing a rearward-acting thrust or recoil on the gun. (In actual practice, the condition shown by part B is far more likely to happen than that shown in E, the reason being that the corrosive powder gases cause erosion of the venturi-openings normally supplied for leading the gases rearwardly out of the guns chamber).

Regardless of which recoil condition of the gun is to be corrected, i. e., type B or E of the drawings, the novel compensating device of this invention can readily solve the problem. To illustrate how positively the present invention can correct a given gun recoil condition by altering the algebraic sum of the opposing thrusts given the gun, parts C and F of Fig. 7 shows how the direction of recoil of the gun shown in B and B, respectively, can be completely reversed. By spacing the compensating ring 21 an axial distance from the center of the powder charge, there is caused to be set up a differential in the powder gas pressures acting on the forward and rearward faces of the ring. The ring spacing can be so adjusted that the sum of the forces acting on the ring and on the chamber in one direction exceed the sum of similar forces acting in the opposite direction. In part C the ring adjustment has been so made that rearwardly acting forces exceed the forwardly acting forces and thus, the same gun which in part B recoiled forwardly, is made to recoil rearwardly. In part F the ring adjustment has been so made that forwardly acting forces exceed the rearwardly acting forces, and thus, the same gun which in part E recoiled rearwardly, is made to recoil forwardly.

Of course, the problem has been not to reverse the direction of a given guns recoil, but to overcome and eliminate it entirely. Obviously, this can be accomplished by properly adjusting the axial setting of compensating ring 21. Thus, in part D an arrangement is shown by which the novel compensating ring completely neutralizes the recoil inherent in the gun shown in part B. Similarly, in part G an arrangement is shown by which the novel compensating ring completely neutralizes the recoil inherent in the gun shown in part E.

It should be understood that the various positions of ring 21 shown in the Fig. 7 diagrammatic illustrations are not necessarily the positions required in the actual gun. By virtue of the fact that the gun has restricted venturi openings (shown at 16 in the drawings, and more fully described and illustrated in the aforementioned copending applications) the actual gun practically always has the relationship of the breech opening-to-barrel bore represented by parts EFG of Fig. 7. Hence, placement of the compensating ring is never made adjacent the rear end (i. e. the left end in the drawings) of the powder charge as the forwardly acting force on the rearward face of the ring is required to be greater than the rearwardly acting force on the forward face of the ring. The position of the ring which will best achieve its recoil compensating function will not depend upon its axial relationship with respect to the cartridge case, but rather with respect to the gases which will emanate from the case C. This in turn will depend on the distribution of the powder within the case, the distribution of the perforations in the case walls, etc. Thus, in the illustrated gun of Fig. 1, the maximum distance the ring 21 can be spaced from the rear end of the cartridge case is about /3 the length of the case. However, it will be obvious from the foregoing explanation that the gun or the powder charge can have certain relationships that would require ring 21 to be located a greater distance toward or away from the barrel in order to function properly.

The proper location of the recoil compensating ring 21 can be determined very readily. Originally, this determination can be made by mathematical calculations which need not be described here. After use, or in the field, the most expeditious manner of positioning the ring probably is to fire a few test rounds, and then adjust the ring forward or rearward as the direction of the guns initial recoil is determined. The movement and mounting of ring 21 is quite simple and is done by placing a number of spacers 20 on bolts 18 between the rear face of the ring and the front face of reliner 14 (see Fig. 1). If the ring is required to be located at a point intermediate the two ends of bolts 18, some of the spacers 20 can be placed between the front face of the ring and the head 19 of the bolt, as indicated at 20A in Fig. 6. Thus placed, the extra spacers aid in maintaining the proper placement of the ring and at the same time are kept available at all times for use, when required, in incredasing the distance between the ring and the guns rear en Referring to Fig. 1, the operation of this invention, as actually carried out and proven in laboratory and field tests with a gun of the type there illustrated, can now be described and understood. When the propellent powder charge (not shown) within the cartridge case C is fired to propel the projectile P out of the barrel 10, the powder gases issuing through the openings in the perforated cartridge case C set up forces which act on the front face of ring 21 to push it rearwardly, and other forces which act on the rear face of ring 21 to push it forwardly. Since ring 21 is secured (by means of bolts 18) to reliner 14, which is in turn threadedly secured to chamber 13 as earlier described, the forwardly and rearwardly acting forces on ring 21 are thus transmitted to the gun itself. For reasons earlier made clear, the ring can be axially adjusted until the algebraic sum or differential of the opposing forces acting on either face of the ring is sufficient to be equal and opposite in direction to the normal recoil forces which would act on the gun ilf ring 21 were absent, thereby eliminating all gun reco1 From the foregoing, it will be seen that this invention provides a durable and rugged device which can be simply and quickly adjusted, even by soldiers in the field of battle, to maintain recoilless guns of the type herein illustrated in their optimum condition of minimum or zero recoil.

I claim:

1. In a recoilless gun having a barrel communicating with a cartridge chamber which is provided at its opposite end from said barrel with a rearwardly extending venturi opening for the escape of gases which counteract the guns recoil, a recoil compensating device located in the chamber opposite to and spaced from the throat of the venturi opening and adapted to receive on its forward and rearward faces such different pressures of the powder gases generated by the combustion of propellent powder in the cartridge chamber as to provide a thrust on said gun equal to and acting in a direction opposite to the thrust which normally would be operable on said gun if said device were not present.

2. Means for giving to an open breech gun, by rearwardly expelled explosion gases formed upon firing a projectile from said gun, a forward impulse so as to counteract the guns recoil if same be in a rearward direction or a rearward impulse so as to counteract the guns recoil if same be in a forward direction; said means and gun including: a projectile-directing barrel, a chamber communicating with the rear end of said barrel, and a recoil compensating ring having relatively flat front and rear faces and mounted in said chamber so as to confront and be spaced from the inlet to said opening and being located adjacent the walls of said chamber so that the combustion of a projectile-propellent charge in said chamber creates a differential pressure on said compensating ring and on said gun, the resultant of said pressure differential tending to give the gun either a forward or rearward impulse depending upon the position of said compensating ring with respect to the propellent charge placed in said chamber.

3. A recoilless gun, including, a projectile-directing barrel, a cartridge-containing chamber attached to the rear end of said barrel, a ring-like reliner removably fixed crosswise of said chambers rear portion and having at least one venturi-like opening extending axially therethrough, the bore of said barrel and the interior of said chamber and the venturi-opening being in axial commu nication, a flat recoil compe sating ring mounted Within and crosswise of said chamLer in front of said reliner, and axially-extending elongated supports mounting said ring on said reliner in spaced confronting relation to the inlet leading to said venturi-opening, the space between said ring and said reliner determining the relative amounts of the forward and rear-acting stresses given the gun by the gas pressures differentially acting on the front and rear faces of said compensating ring upon firing a cartridge in said chamber.

4. A recoilless gun, including, a projectile-directing barrel, a cartridge-containing chamber attached to the rear end of said barrel, a ringlike reliner removably fixed crosswise of said chambers rear portion and having at least one venturi-like opening extending axially therethrough, the bore of said barrel and the interior of said chamber and the venturi opening being in axial communication, a fiat recoil compensating ring mounted within and crosswise of said chamber in front of said reliner, bolts supporting said ring on said reliner, and washers References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,380,358 Cooke June 7, 1921 2,406,537 Goehmann Apr. 27, 1946 2,421,522 Pope June 3, 1947 FOREIGN PATENTS Number Country Date 33,908 Denmark Nov. 24, 1924 89,970 Sweden Aug. 10, 1937

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