BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to the interface between an endless conveyor in a supply chute of a substantially stationary ammunition supply system and a recoiling, high rate of fire gun. 
     2. Prior Art 
     The conventional interface between an endless conveyor in a supply chute of a substantially stationary ammunition supply system and a recoiling, high rate of fire gun is provided by at least a length of flexible chuting such as is shown, for example, in U.S. Pat. No. 2,993,415 issued July 25, 1961 to E. W. Panicci et al. U.S. Pat. No. 2,993,415 shows the use of an endless conveyor within the supply chute and is an improvement over U.S. Pat. No. 2,935,914 issued May 10, 1960 to B. Darsie et al which shows a rigid chute through which the successive mutually abuting rounds are pushed. Other systems utilize linked ammunition, rather than an endless conveyor, and are shown, for example, by U.S. Pat. No. 2,477,264 issued July 26, 1949 to C. B. Pearson et al, U.S. Pat. No. 3,307,452 issued Mar. 7, 1967 to R. Meunier and U.S. Pat. No. 3,250,360, issued May 10, 1966 to C. V. Correll. However, high rate of fire systems utilize an endless conveyor as shown, for example, by U.S. Pat. No. 3,429,221, issued Feb. 25, 1969 to R. G. Kirkpatrick, and U.S. Pat. No. 4,044,649, issued Aug. 30, 1977 to F. A. Wilder. 
     The flexible chuting, comprised of partially overlapping layers of bent-up sheet metal which serve as a guide for the endless conveyor and its ammunition, conventionally has a short service life. 
     SUMMARY OF THE INVENTION 
     An object of this invention is to provide an interface structured to accommodate gun movement relative to a stationary supply chute, all having an endless conveyor for ammunition within, which substantially isolates the gun movement from the supply chute. 
     A feature of this invention is an interface structure between a recoiling gun and a stationary ammunition supply having a plurality of elongated, individually rigid, guide elements, for providing continuous guide surfaces for the individual elements which are connected to form the endless conveyor and the individual rounds of ammunition respectively carried thereby, and having three degrees of freedom of movement. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     These and other objects, features and advantages of this invention will be apparent from the following specification thereof, taken in conjunction with the accompanying drawing, in which: 
     FIG. 1 is an idealized rear view of a gun and ammunition handling system in a turret arrangement and having an embodiment of this invention; 
     FIG. 2 is a perspective view of the embodiment of FIG. 1; 
     FIG. 3 is a perspective view of a detail of the embodiment of FIG. 1; and 
     FIG. 4 is an end view of the embodiment of FIG. 1. 
    
    
     DESCRIPTION OF THE INVENTION 
     The turret arrangement 10 shown in FIG. 1 may be broadly of the type shown in U.S. Pat. No. 4,437,384, issued Mar. 20, 1984, to D. P. Tassie, but having an ammunition handling system including a drum storage 12 and a flexible endless conveyor system 14 of the types shown in U.S. Pat. No. 3,696,704, issued Oct. 10, 1972 to L. F. Backus et al. The turnaround and handoff-to-the-gun feeder mechanism 16 may be of the type shown in U.S. Pat. No. 3,429,221 issued Feb. 25, 1969 to R. G. Kirkpatrick and U.S. Pat. No. 4,044,649, issued Aug. 30, 1977, to F. A. Wilder. The gun 18 may be of the type shown in U.S. Pat. No. 4,314,501, issued Feb. 9, 1982 to R. G. Kirkpatrick et al and the feeder mechanism 20 may be a single feed rather than the dual feed of the type shown in U.S. Pat. No. 4,434,699, issued Mar. 6, 1984 to D. P. Tassie. The endless conveyor system 14 includes a plurality of conveyor elements 30 (shown in FIGS. 3 and 4) interconnected in an endless train as shown in U.S. Pat. No. 4,044,649, supra. The endless train passes through an exit unit 32 having a rigid housing at the drum 12, two side-by-side lengths of flexible chuting 34 and 36, two side-by-side lengths of rigid chuting 38 and 40 mounted to the turret elevation structure 42, two side-by-side mechanisms 44 and 46 each embodying this invention and shown in FIG. 2, and the turnaround 16 having a rigid housing. 
     Each conveyor element 30 is adapted to convey a round 50 of ammunition having a projectile 52 with a nose 54, a base, and a band 56, and a case 58 with an extractor disk 60, an extractor groove 62, a body 64, a conical shoulder 66, and a neck 68 receiving the base of the projectile. 
     Each conveyor element 30 has a body 70, an aft plate 72 integral with the body and having a concave cylindrical surface adapted to receive the case body, a forward plate 78 integral with the body and having a concave conical surface adapted to receive the case shoulder 66, a single forwardly projecting arm 80 integral with the body and having a transverse hole 82 to receive a pivot pin 84, a bifurcated rearwardly projecting arm 86 integral with the body and having a transverse hole 87 to receive the pivot pin, a forward leg 92 integral with and depending from said plate and having a transversely extending foot 94, and an aft leg 96 integral with and depending from said plate and having a transversely extending foot 98. 
     A typical gun 18 (and its feeder 20 and turnaround 16), here taken as a four barrelled, 30 mm gatling type gun, has significant recoil fore and aft movement from its static, non-firing disposition at which it may be nominally aligned with the interface of the fixed feed system 38, 40. The gun also undergoes some oscillatory motion in the plane which is transverse to its recoil motion. Ideally, the gun when firing normally should be at its best alignment with the fixed feed interface. For the exemplary gun, there will be the following fore and aft displacements: 
     
         ______________________________________Peak Counter Recoil   +0.30   inchesStatic Gun            0.00Normal Firing Displacement                 -0.38Normal Maximum Recoil -0.75Maximum Recoil (Misfire)                 -1.00Dither About The Normal                 ±0.38Firing Displacement______________________________________ 
    
     The interface structure 44 (and 46 respectively) serves to isolate the movement of the gun, feeder and turnaround from the stationary interface of the remaining feed chute system, while providing smooth, uninterrupted guide surfaces for the endless train of conveyor elements 30 and their respective rounds 50 of ammunition. 
     Assuming an ideal situation of a constant lateral spacing, for example, nine inches between the gun interface and the feed interface, then the fore and aft changes of displacement for the above described exemplary gun are: 
     
         ______________________________________             Length ofFrom              Guide From          AngularStatic From Normal             Normal Firing                         Change In                                 Deflec-Point  Firing Point             Point       Length  tion______________________________________+0.30 in.  +0.68 in.  9.026 in.     .026 in.                                 4.321° 0.00  +0.38      9.028       .008    2.418°-0.38   0.00      9.000       0.000   0.000°-0.75  -0.38      9.008       .008    2.418°-1.00  -0.62      9.021       .021    3.941°______________________________________ 
    
     The lateral spacing does not remain constant due to the inherent lack of rigidity of the total system, and it has been estimated at ±0.10 inches of lateral motion occurs during firing. Therefore, the interface structure must accommodate this additional distortion, and an accommodation of ±8° and +0.300 in. and -0.20 in. suffices. 
     The interface structure 44 (and 46 respectively) includes a feed side bracket 100 and a gun side bracket 102. The structure 44, as shown, has the conveyor elements mounted above the rounds of ammunition (i.e., &#34;element above&#34;), while the structure 46 has the elements mounted below the rounds of ammunition (i.e., &#34;element below&#34;). 
     The brackets 100 and 102 are interconnected by: A U-shaped beam 104 providing (when element above) a broad flat surface 104a for supporting the projectile 52. A L-shaped beam 106 providing (when element above) a narrow flat surface 106a for supporting the narrower full diameter of the case body 64. A L-shaped beam 108 providing (when element above) a narrow flat surface 108a for supporting the wider full diameter of the case body 64. A U-shaped beam 110 providing a groove 110a for receiving the foot 94 of the element 30, an inner flat surface 110b for supporting (when element above) the foot 94 and an inner flat surface 110c for supporting (when element below) the foot 94, and a narrow flat surface 110d for limiting transverse travel of the leg 92. A U-shaped beam 112 providing a groove 112a for receiving the foot 98 of the element 30, an inner flat surface 112b for supporting (when element above) the foot 98 and an inner flat surface 112c for supporting (when element below) the foot 98, and a narrow flat surface 112d for limiting transverse travel of the leg 96. A U-shaped beam 114 providing (when element below) a broad flat surface 114a for supporting the projectile 52. A U-shaped beam 116 providing (when element above or below) a wide flat surface 116a for limiting transverse travel of the body of the element. A L-shaped beam 118 providing (when element below) a narrow flat surface 118a for supporting the wider full diameter of the case body. An L-shaped beam 120 providing (when element above or below) a narrow flat surface 120a for limiting transverse travel the base surface of the case disk 60. It should be noted that the concave conical surface of the element 30 limits transverse travel of the shoulder 66 of the case, and thus the case is transversely constrained between the element conical surface and the surface 120a, and between the surfaces 106a and 108a and the surface 118a and the element 30. 
     Each of these beams is pivotally mounted at its respective ends to a respective bracket by means of a double slot (e.g. 130), in the case of an U-shaped beam (e.g. 112), or a single slot in the case of a L-shaped beam (e.g. 118), which slot passes a bolt 132 held by a lock nut 134. The lock nut is less than fully clamped down to permit the beam to twist slightly with respect to the bolt and the bracket, besides sliding to and from with respect to the bolt and the bracket to enlarge or contract its effective length between the two brackets. 
     The adjacent fixed chutes 38 and 40 and the turnaround 16 have guide surfaces for the elements 30 and the cases 64 as shown in U.S. Pats. Nos. 3,429,221 and 4,044,649, supra. To preclude the transient development of lacunae in the continuity of the support sufaces of the fixed chutes and the turnaround and the support surfaces of the interface structure 44 and 46, the end brackets 100 and 102 are respectively provided with fixed support surfaces adjacent to and overlapping the end of the support surface of each beam, (except projectile guiding beams 104 and 114). 
     On the bracket 100, there are: A boss 150 having a narrow flat surface 105a spaced adjacent to and coplanar with the end margin of the surface 106a. A boss 152 having a narrow flat surface 152a spaced adjacent to and coplanar with the end margin of the surface 108a. A box 154 having a narrow flat surface 154a spaced adjacent to and coplanar with the end margin of the surface 120a plus a boss 156 having a narrow flat surface 156a spaced less than the diameter of the base of the disk 60 and coplanar with the end margin of the surface 120a. A boss 158 having a narrow flat surface 158a space adjacent to and coplanar with the end margin of the surface 118a. a U-shaped beam 160 providing a groove 160a for receiving the foot 98 of the element 30, an inner flat surface 160b for supporting (when element above) the foot 98 and an inner flat surface 160c for supporting (when element below) the foot 98, and a narrow flat surface 160d for limiting transverse travel of the leg 96. A U-shaped beam 162 providing a groove 162a for receiving the foot 94, an inner flat surface 162b for supporting (when element above) the foot 94 and an inner flat surface 162c for supporting (when element below) the foot 94, and a narrow flat surface 162d for limiting transverse travel of the leg 92. 
     The beam 160 is fixed to the bracket 100, by two bolts 164 and respective nuts, in nominal alignment with the beam 112 when the interface unit is in its rectangular, nondistorted disposition. The mutually adjacent ends of the beams 160 and 112 have respective curvilinear edges 160e and 112e which mutually define a curvilinear gap which permits the beam 112 to swing through the desired distortion, previously defined at ±8° and permits a contraction of one-half of the desired contraction, previously defined as -0.20 inches. The shape of the gap provides that the foot 98, as it passes from the beam 160 to the beam 112, is at all times supported by the respective surfaces of either or both beams and never falls into the gap, even when the gap is at maximum width as defined by the slot 130 and the bolt 132. The surfaces 160a and 112a, 160b and 112b, 160c and 112c, 160d and 112d are normally coplanar. When the beam 112 is twisted, the clearances are still adequate to permit free movement of the foot from one beam to the other (and vice-versa). The beam 162 is similarly aligned and has a curvilinear gap with the beam 110. 
     On the bracket 102 there are provided a symmetrical set of bosses 150&#39;, 152&#39;, 154&#39; (not visible), 156&#39;, and 158&#39;, and beams 160&#39; (not visible) and 162&#39; (not visible), with respective surfaces and gaps as described for the bracket 100.
An interface structure between a recoiling gun and a stationary ammunition supply having a plurality of elongated, individually rigid, guide elements, for providing continuous guide surfaces for the individual elements which are connected to form the endless conveyor and the individual rounds of ammunition respectively carried thereby, and having three degrees of freedom of movement.