US2876681A - First round recoil reducer for automatic guns - Google Patents

Description

' March 10, 1959 I K. w. MAIER FIRST ROUND RECOIL REDUCER FOR AUTOMATIC GUNS Filed June 7, 1956 Sheets-Sheet 1 INVJNTOR,

NM M M M z w FIRST, ROUND RECOIL RBDUCER FOR AUTOMATIC GUNS Filed June 1, 1956 K. w. 'MAIERY March 10; 1959 2 Sheets-Sheet 2 United States Patent 6 FIRST ROUND RECOIL REDUCER FOR AUTOMATIC GUNS Karl W. Maier, Torrance, Calif., assignor to Northrop Aircraft, Inc., Hawthorne, Calif., a corporation of Cahforuia Application lune 7, 1956, Serial No. 589,971

8 Claims. (Cl. 89-198) This invention relates to recoil apparatus and more particularly to a recoil mechanism for automatic guns or the like and which functions in a manner rendering the guns initial recoil movement substantially equal to subsequent recoil movements thereof.

The deflection range through which the reciprocating components of an automatic gun may travel is quite frequently limited by surrounding structure. The above is especially true in the case of automatic guns mounted, for example, in aircraft turrets and like structure which necessarily subjects the movement of recoiling parts to very rigid limitations. For reasons that are well known in the art, the initial recoil deflection of automatic guns, i. e. the recoil resulting from the ignition of the first round of a burst, greatly exceeds subsequent recoils of the gun. If the initial recoil deflection of the gun is reduced, i. e. so that the initial recoil is substantially equal to the steadystate recoil motion of the gun, the gun may be mounted in limited quarters such as those encountered in mounting an automatic gun in an aircraft turret or the like.

Accordingly it is an object of this invention to provide a recoil mechanism for automatic guns which render the initial recoil thereof substantially equal to the steadystate recoil motion of the gun. Another object is to provide a recoil mechanism for automatic guns which embodies an energy absorbing mechanism which is active during the recoil of the first round of a burst fired therefrom and is rendered inactive during subsequent rounds.

Another object is to provide a recoil mechanism for automatic guns which is economical to manufacture and which requires a minimum of maintenance after the initial installation thereof.

The above and other objects and advantages will become more apparent from the following description and drawings in which the same reference characters denote like parts throughout the several views. It is to be expressly understood, however, that the drawings are for the purpose of illustration only and not a definition of the limits of this invention, reference being had for this purpose to the appended claims.

In the drawings:

Figures 1 and 2 are-elevationaland plan views, respectively, of an automatic gun embodying a recoil mechanism as disclosed herein.

Figure 3 is a cross-sectional detail view of the recoil mechanism shown in Figures 1 and 2 and taken along the line 3-3 of Figure 2.

Figure 4 is an exploded view in perspective of certain cooperating portions of the recoil mechanism shown in Figure 3. 1

.Figure 5 shows time-deflection curves of the reciprocating components of an automatic gun dampened respectively by a recoil mechanism containing the energy absorbing facility as disclosed herein and a recoil mechanism not utilizing the aforementioned energy absorbing facility.

. Referring now to the drawings and particularly Figures 1 and 2,.in these figures an automatic gun 20 employing 'ice a recoil adapter assembly 21 including a first-recoil reducer assembly of the type disclosed herein is utilized. As shown in these figures the major recoil components of the. gun include a drum 22, drum support 23, and gun barrel 24 mounted in a conventional manner for reciprocal movement on a receiver member 26. The recoil adapter assembly 21 normally acts to arrest reciprocal movements of the above named recoil components short of fore and aft fixed stops (not shown) located internally of the gun, the location of these stops being indirectly dictated by installation limitations. Such an installation requires that all fore and aft movements of the recoil components of the gun, for example the drum support 23, etc., be confined within a very limited range as is quite often the case in automatic guns mounted in aircraft turret installations. How the aforementioned first-recoil reducer assembly functions to accomplishe such an intallation will became apparent as the disclosure progresses.

The recoil assembly 21 includes a cross member 27 having trunnion type bearings which are pivotally mounted in gun structure 28 fixedly secured to the receiter 26 and carries a barrel support member 29 at its mid-section. Also carried by the member 27 is a pair of recoil structures hereinafter referred to as individual recoil assemblies 31. Inasmuch as these latter assemblies are of identical construction and operation the description of one will also be applicable to the other.

Referring to Figure 3 it will be seen that one of the individual recoil assemblies 31 includes a cylindrical housing 32 inwardly flanged at the aft end thereof and inwardly threaded at its forward end as indicated by the numerals 33 and 34, respectively. The housing 32 is divided into fore and aft compartments by an annular shaped center stop member 36 secured in position as by screws or the like. operationally mounted in the forementioned fore and aft compartments is a sleeve brake adapter assembly 37 and the first-recoil assembly 38, respectively.

Identified by the numeral 39 in an adapter rod which is common to and cooperates with the assemblies 37 and 38. The rod 39 is characterized by including an annular flange 42 located adjacent the midportion thereof and which is slightly less in diameter than the inner diameter of the stop member 36. Further the adapter rod is threaded at each end as indicated at 41 and is secured to the drum support 23 by means of the aft threads. The rod 39 is further characterized in that it is mounted for sliding longitudinal movement within the housing 32 as the drum support 23 etc. reciprocates in response to recoil and counter-recoil movements of the gun.

The sleeve brake adapter assembly 37 is of conventional construction, therefore its construction and operation will not be described in detail. Briefly the assembly 37 includes a retainer 43 having threads mating with the threaded portion 34 of the housing 32. Mounted respectively adjacent the member 36 and inner end of the retainer 43 are a pair of perforated disc-shaped brake stops 44. Extending through the perforations of the stops 44 in sliding relation are fore and aft pronged members 46 and 47 which provide respective fore and aft seats for a precompressed recoil spring 48. The outer ends of the prongs of the members 46 and 47 normally are in contact with flange 42 and a forward nut 49, respectively. Mounted internally of the spring 48 is a brake assembly 51 which includes a brake lining 52 secured to the rod 39, a braided wire brake sleeve 53, fore and aftbrake seats 54 and 56, respectively, and a precompressed spring 57 mounted between the seats 54 and 56.

latter throughout its operating range and under varying shown the portion 62 is divided longitudinally into eight (8) identical resilient prongs 64 terminating inwardly in the flanged base portion 63. The base portion 63 is slightly less in diameter than the inside diameter of the housing 32 andin its assembled position provides an inner seat-for the spring 58. Each of the prongs 64 actually constitutes a leaf spring arranged in tubular configuration. similar to a collet or the like, and taper in thickness from their inner to their outer ends where they terminate in tapered surfaces and are provided with identically shaped and positioned hooks or projections 66 slightly forward of their outer ends. The projections 66 have forward faces which are normal to and aft faces having a slanting relation with respect to the axis of the body portion 62. Accordingly it will be seen at such times as the prongs 64 are urged into contacting relationships the individual projection 66 define a continuous annular flange tapering rearwardly of cylindrical and conical configuration.

With the detent member 59 in its assembled position inthe sear sleeve 61 it will be seen by referringto Figure 3 that the inner diameter of the body portion 62 is somewhat greater than the diameter of therod 39. Accordingly an annular chamber 71 is provided in which a re tainer spring 72 ismounted. This spring bears on a shoulder defining the inner end of the chamber 71 and an annular collar surrounding and pinned to the rod 39. The retainer spring 72 functions to maintain the flanged base of the detent member 59 in contact with the flange 42, except at such times as the latter flange is located to the right of the stop member 36, as viewed in Figure 3. The scar sleeve 61 consists mainly of a body portion 67 which is also of tubular configuration. The inside diameter of the body portion is such that it slidably receives the body portion of the detent 59 at such times as the prongs 64 are in contacting or near contacting relation. An annular flange'68, slightly less in diameter than the inside diameter of the housing 32, extends from the aft end of the body portion and in the assembly position thereof provides an aft seat for the spring 58 and itself may seat on the annular flange 33. Formed in the inner wall of the aft end of the body portion 67 is a plurality of spaced parallel annular grooves 69 having the same cross-sectional configuration as the projections 66. The grooves 69 receive the projections 66 during the opera tion of the recoil assembly 31 at a time and in a manner presently explained. At such time as the projections 66 are received in the grooves 69, or the projections 66 are secured to the aft end of the sleeve 61, the relative positions of the detent member 59 and sear sleeve 61 are hereafter referred to as their contracted positions.

Referring to Figure 3, in which the various components of the recoil assembly 31 are shown in their assembled relation, it will be seen that the flanged base portion 63 and flange 68 are bottomed on the stop member 36 and flange 33, respectively. This is true although a filler ring 70 is positioned between the flanges 68 and 33. The re coil reducer 38, and retainer springs 48, 58, and 72, respectively, as shown in Figure 3 are in their fully extended assembled attitudes. Under these conditions the rod 39 is caused to assume the position as seen in Figure 3 hereinafter referred to as the neutral or rest position of the rod. Also the relative positions of the detent member 59 and sear sleeve 61 as shown in Figure 3 are hereafter referred to as their extended positions.

The first-recoil reducer assembly 38 is completed by an aft nut 73 secured to the aft end of the rod 39 by means of the threads 41. This nut includes a flange 74 and annular end portion 76, the latter being snugly received in the inner bore of the sear sleeve 61. The flange 74 of the nut 73 provides a bearing surface for the outer end of the sear sleeve and passes freely through the open ing defined by the flange 33 at such time as the rod 39 is moved to the right of its neutral position.

As previously mentioned the housings 32 are rigidly attached to the receiver 26 by means of trunnion supports while the rod 39 is attached to and moves with the drum support 23. Therefore, kinematically speaking the housings 32 are a part of the receiver 26 while the adapter rod 39 is a part of and moves with the drum support 23. In view of the above explanation and inasmuch as the various components of the recoil assembly 31 have been described a better understanding of the recoil assembly, and especially of the first-recoil reducer assembly 38, will be forthcoming by referring to Figure 5 and the following description of the operation of the recoil assembly.

By referring to the time-deflection curves of Figure 5 it will be seen that the deflection range, due to the recoil and counter-recoil movements of the gun 20 as illustrated in the present embodiment, is limited to a distance of approximately one and three quarters inches (1.75") which is the distance between the front and rear stops.

Neglecting momentarily the action of the first-recoil reducer assembly 38.the. time-deflection curve for the recoil components of the gun 20 is represented by the dotdash curve of Figure 5. Due to the excessive recoil momentum and aft deflection F jof the first round in comparison to that the the later rounds (steady-state dither deflection A F) of the burst (up to 0.75 inches overtravel) it is almost impossible within the given aft deflection range of 1.50 inches to control both the recoil of the first round and the steady-state recoil motion. It is apparent from this curve that both F (aft deflection of the first round) and A F (steady-state dither deflection) can not both be satisfactorily controlled. Either the recoiling gun parts will strike the rear stops during the initial recoil or alternately extremely high brake forces must be applied. The latter inherently leads to erratic recoil forces and to a reduction in the rate of fire which will in turn result in inefficient operation of the automatic gun.

Further the short-long pattern of the curve, represented by that portion labeled alternating recoil occurring at the end of the first round of a burst, is due to the fact that the final forward velocity V of the counterrecoiling gun parts is so high that the merging momenta at ignition of the second round results in an undesirable short second recoil.

The solid continuous line curve of Figure 5 represents the time-deflection curve of the recoil components of the automatic gun 20 at such time as the first-recoil reducer assembly 38 is utilized in conjunction with the sleeve brake adapter 37.

Upon ignition of the first round of a burst, the drum support 23 recoils, thus compressing the reducer spring 58 by means of the flange 42 of the rod 39 and the base 63 of the detent 59. A typical condition as outlined above is represented by X in Figure 5 at an aft deflection (F) of 0.70 inch. After an aft deflection of approximately 0.90 inch (point B in Figure 5), the projections 66 of the detent 59 reach the innermost one of the grooves 69 formed in the sear sleeve 61 and instantly snap into this groove. Usually the compression of the reducer spring 58 will continue further, due to the kinetic energy of the drum support 23 and other recoil compon'ents of the gun 20.

During the above active phase of the assembly 38 the projections 66 of the prongs 64 are guided out of the innermost groove 69 by the rear taper of this groove.

Due to the expansion tendency of the detent, the prongs 64 are always in contact with the inner surface of the sear sleeve and will snap outwardly instantly as soon as conditions permit. For example, the projections 66 may engage in the outermost groove 69 (point B in Figure 5 at an aft deflection of 1.10 inches) or even the aft end surface of the sear sleeve at the aft deflection of 1.30 inches. The compression of the reducer spring 58 continues until the drum support 23 and receiver 26 have equal velocity (point C at an aft deflection of 1.25 inches).

Accordingly it will be seen that at the beginning of the counter-recoil stroke the projections 66 may engage either the innermost or outermost groove 69 or the end surface of the sear sleeve 61. However, in the embodimeet shown the projections 66 engage the outermost groove 69 at an aft deflection of 1.10 inches (point D; in Figure '5). This engagement of the detent with the sear sleeve terminates the active phase of the first-recoil reducer assembly 38 and initiates its inactive phase.

During the active phase of the first-recoil reducerassembly, the force of the reducer spring 58 acts on the flange 42 of the rod 39 through the base 63 of the detent member. Therefore, it is seen that the reducer spring 53 assiststhe sleeve brake adapter assembly 37 in decelerating the first round recoil motion of the drum support 23 and other recoiling parts, as indicated by the lower solid line in Figure 5. The mechanism 38 is in an active status for all positions of X from point A to point D From point D on the detent being engaged in the outermost groove 69 the mechanism 38 is no longer active. The force of the spring 58 is no longer transmitted to the receiver 26 and drum support 23, rather the springs force is transmitted from the base 63 back to the sear sleeve in'a manner which may be described as a mechanical short circuit. The spring 58, sleeve 61, and detent member 59 now comprises a self-containe unit which is momentarily incapable of exerting any force on the rod 39 and, therefore, constitutes an inert mass.

In order to reactivate the mechanism 38 for the first recoil of the next burst, the detent 59 must be disengaged from the sear sleeve 61 at the end of a preceding burst. Due to the absence of further ignition at the end of a burst the gun recoil parts will continue their forward motion and will cross the neutral position as represented by point H in Figure 5. It is this condition that is utilized to disengage the detent 5? and sleeve 61.

All positions through which the rod 39 travels in a direction aft of its neutral position, represented by the point H of Figure 5, is hereinafter referred to as the major or aft operating range of the rod 39. Also all positions through which the rod 39 travels in a direction forward of its neutral position are hereinafter referred to as the minor or forward operating range of the adapter rod.

At such times as the rod 39 passes the neutral position thereof, while traveling forward, the detent 59 can no longer follow the movement of the rod as forward movement of the detent will be arrested by the stop member 36 (point I in Figure 5). From this point on the rod 39 will move relative to the detent 59. The internal conical surface of the nut 73 will now engage the tapering or cone-shaped tips of the prongs 64 and force the latter to move inwardly thus freeing the projections 66 from the groove 69. The highly compressed reducer spring 58 is now suddenly released and acts to propel the sear sleeve 61 to the rear until it bottoms on the flange of the nut 73.

Upon impact of the spring 58 on the flange of the nut 73, the reducer spring 58 assists the sleeve brake assembly 37 in decelerating the forward motion of the rod 39. At this time the retainer spring 72, in addition to its function as previously outlined, also aids in reducing the maximum forward deflection (point J in Figure 5). After ends of said housing and a nut member on the aft end with the solid line curve A, B B etc. beyond the point K as shown in Figure 5.

From the foregoing it will be apparent that a mecha nism has been disclosed which provides a novel and satis factory solution to the well known and existent problem of excessive first-round recoils of automatic guns and meets the many objects of the invention as set forth above.

While in order to comply with the statute, the invention has been described in language more or less specific as to structural features, it'is to be understood that the invention is now limited to the specific features shown, but that the means and construction herein disclosed comprises a preferred form of putting the invention into effect, and the invention is therefore claimed in any of its forms or modifications within the legitimate and valid scope of the appended claims.

What is claimed is:

1. A recoil mechanism for automatic guns comprising: a cylindrical housing having fore and aft portions; an

adapter rod including contact means mounted in said housing for longitudinal movement therein through fore and aft operational ranges; a brake adapter mounted in the forward portion of said housing; a first round recoil reducer assembly mounted in the aft portion of said housing; said recoil reducer assembly includes respective stop elements extending inwardly adjacent. the center and aft of said rod, detent means including an expandable tubular member and sear sleeve member assembled in telescopic relation and mounted in surrounding relation on said rod at a location between said stop elements and the latter members being movable between extended and contracted positions, and major resilient means mounted on said detent means in a manner urging said tubular and sear sleeve members toward their extended position in which the latter members are respectively bottomed on said stop elements; said brake adapter and recoil reducer cooperating to position said rod in a rest position in which said contact means defines the innermost ends of said fore and aft ranges at such times as said rod is free of external forces; and said major resilient means acts to resist initial movement of said rod in an aft direction from said rest position and said tubular and sear sleeve members cooperate to render said major resilient means ineffective thereafter as said rod moves through said aft range and predetermined portion of said forward range.

2. Apparatus as set forth in claim 1: further characterized in that said tubular member includes a plurality of rearwardly extending resilient portions joined at their forward ends to provide an annular base and have projections located adjacent the aft ends thereof, the aft end of said sear sleeve defines a plurality of annular grooves, shaped to receive said projections at such time as said rod initially assumes a predetermined position in said aft range, and an outwardly extending annular shoulder, and said major resilient means is mounted between said annular base and annular shoulder.

3. Apparatus as set forth in claim 2: further characterized in that said nut member defines a combined truncated conical and cylindrical cavity adapted to re ceive and deflect the resilient portions of said tubular member inwardly thereby freeing said projections from said grooves at such times as said rod assumes a predetermined position in said forward range.

4. Apparatus as set forth in claim 1: further characterized in that the forward end of said tubular member defines an annular internal shoulder and said recoil re newest ducer assembly includes auxiliary resilient means mounted to bear on said annular internal shoulder to continuously urge said tubular member in a forward direction.

5. Ina recoil mechanism for guns having components which reciprocate during a firing burst, the combination comprising: an elongated housing having fore and aft portions; an adapter rod including contact means and having an aft end adapted to be attached to the components of said gun which reciprocate during a firing burst; said rod being mounted in said housing for longitudinal movement therein through fore and aft operating ranges in response to movements of the components of said gun which reciprocate during a firing burst from a rest position assumed at such times as said gun is inoperative; a first round recoil reducer assembly mounted in the aft portion of said housing; said recoil reducer assembly includes respective stop elements extending inwardly adjacent the center and aft ends of said housing and a nut member on the aft end of said rod, detent means including an expandable tubular member and sear sleeve member assembled in telescopic relation and mounted in surrounding relation on said rod at a location between said stop elements and the latter members being moved, by movements of said rod, between extended and contracted positions, and major resilient means mounted on said detent means in a manner urging said tubular and sear sleeve members toward their extended position in which the latter members are respectively bottomed on said stop elements; said recoil reducer assembly acting to position said rod in a rest position in which said contact means defines the innermost ends of said fore and aft ranges at such times as'said gun portions are not reciprocating; and said major resilient means acts to resist initial movement of said rod in an aft direction from said ,rest position and said tubular and sear sleeve members cooperate to render said major resilient means ineffective thereafter as said rod moves through said aft range and predetermined portions of said forward range.

6. Apparatus as set forth in claim 5: further characterized in that said tubular member includes a plurality of rearwardly extending resilient portions joined at their forward ends to provide an annular base and have projections located adjacent the aft ends thereof, the aft end of said sear sleeve defines a plurality of annular grooves, shaped to receive said projections at such time as said rod initially assumes a predetermined position in said aft range, and an outwardly extending annular shoulder, and said major resilient means is mounted between said annular base and annular shoulder.

7. Apparatus as set forth in claim 6: further characterized in that said nut member defines a combined truncated conical and cylindrical cavity adapted to receive and deflect the resilient portions of said tubular member inwardly thereby freeing said projections from said grooves at such times as said rod assumes a pre determined position in said forward range.

8. Apparatus as set forth in claim 5: further char acterized in that the forward end of said tubular member defines an annular internal shoulder and said recoil reducer assembly includes auxiliary resilient means mounted to bear on said annular internal shoulder to continuously urge said tubular member in a forward direction.

References Cited in the file ofthis patent UNITED STATES PATENTS

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