Патент USA US2406047код для вставки
‘Aug. 20, 1946. " ‘w. E. SWIFT, JR ‘2,406,047 ' PROTECTION AGAINST BULLET SPAT'ITER Filed Feb. 18, 1943 . a I 3 Sheets-Sheet 1 5 mgaf??f/l' -' LA 1 I '4 6 . FlG.5 '.\l/ 25‘ I ~ 2a - F‘ G- ‘3 ' _ ' \l/7\ > ~ ' ' INVENTOR ‘ ‘ ' / ‘ WILLARD E. SWIFT JR. > QEWMRMM ATTORNEYS Aug. 20, 1946. . ' I w. E. SWIFT, JR PROTECTION AGAINST BULLET 2,405,047 SPATTER Filed Feb. 18, 1943 ‘ - 3 Sheets-Sheet 2‘ FIG. l5 INVENTORI _ 22 . ‘ ‘ F I G‘ WILLARD E.SWIFT JR. BY v c. éIMwfZFZYJZ‘MM/ ' ATTORNEYS ' Aug. 20, 1946. W. E. SWIFT, JR ' 2,406,047 FIG. 25 ATTORNEYS _ 2,406,047 Patented Aug. 20, 1946 UNITED STATES ‘PATENT OFFICE 2,406,047 ‘ PROTECTION, AGAINST BULLET SPATTER Willard E. Swift, Jr., Worcester, Mass. ‘ Application February 18, 1943, Serial No. 476,362 . r 7. ‘V 1 Claim. (01. 109-78) ‘(Granted under ‘the act of ‘ ' ‘ 1883, as amended April 30, 1928,; 370, O. G. 757) 1 otherwise impracticable, a ?oat de?ector may be inserted in the path or at the end thereof, se cured to one of the walls of the opening and forming with this wall an acute angle facing the The invention described herein may be manu .' factured and used by or for the Government for governmentalpurposes, without the payment to meof any royalty thereon. This invention relates to the prevention of damage caused by bullet splash or spatter enter ing crevices and openings through the walls of armored. structures such as combat tanks and the incident end of the opening. ‘ . ' The underlying theories of the invention are illustrated schematically, and some illustrative embodiments are. shown in the accompanying drawings in which: like. Figures 1 to 13 inclusive are schematic illustra ,Bullet splash or spatter is the phenomenon that tions of the behavior of bullet spatter under vari occurs when small arms ?re strikes an armored ous conditions described below; Figures 14 and 15 are detail sections of a tank surface. Particles of the outer shell and inner ‘core of the bullet are thrown in all directions laterally from the point of impact. At least some of these particles skim along the surface and 15 . enter any opening in line with the surface. More over, on striking another surface, the spatter is turret having spatter protection for the sight opening; Figures 16 to 20 inclusive are detail cross‘sec tions of various armored structure equipped with spatter protection devices; again de?ected in all directions, although with diminished force. Consequently, the bullet spat . , ‘ Figure 21 is a detail cross section of a door ter may be de?ected into openings and will pass 20 structure showing a di?erent form of trap for through to the interior of the structure. This action occurs even if the opening follows an’ ir regular path “having right angle or obtuse angle turns, because of the de?ection of the spatter on striking any obstructing surface. the crack; _. ‘ Figure 22 is a detail section of a door or other structure presenting an opening, with spatter de ?eeting surfaces formed in the opening; 25 Figures 23 and 24 are detail sections of a gun Within a tank, for example, the entering spat rotor with a spatter trap beyond the clearance; ter ‘may cause injury to personnel or may damage some ofitheinternal installations such as tubing housing with spatter traps in the clearance; Figure 216 is a reproduction of Figure 23, illus trating the path of armor piercing fragments, and electrical cables. If the spatter enters be tween relatively movable parts, such as a gun rotor and its housing, it may wedge itself between the parts or may raise a burr on one of them, in .either case immobilizing the movable part. Figure 25 is a detail section of a gun rotor and and . I ' Figure 27 illustrates a similar but shorter path and the insufficiency thereof. ‘ Reference to these views will now be made by ‘ The invention resides in providing various use of like characters which are employed to des 25 means for de?ecting the spatter either at an ignate corresponding parts throughout. intermediate point in its path or at the end of its path through the opening, immediately before it enters the interior of the armored structure. The various forms of de?ecting means can be best selected and applied after an understanding a of the behavior of bullet spatter, and for this rea son the phenomenon is discussed to some extent herein. By way of introduction it is pointed out that the spatter behaves in many respects like a fluid and follows substantially a fluid path on surfaces and in crevices, This will be observed through out the detailed description. Figure 1 illustrates normal incidence against a semi-hard ?at surface I. The bullet approaches along the arrow 2, and the spatter is distributed and analysis of the distribution of the spatter. 45 in all directions from the point of impact along ., The invention is basedlargely on the discovery As a result of such observations, I have found that a number of de?ecting surfaces introduced in the path of the spatter will progressively reduce its momentum until it loses its damaging effect. An other construction based on these observations is the provision of a concave surface presented to the path of the spatter and extending through approximately 180 degrees, so thatrthe direction of the‘spatter is substantially reversed. Where the plane of the surface as indicated by the ar rows 3. The bullet is a ball cartridge which does not penetrate the surface.v In Figure 2 an armor piercing projectile 4 has struck the member 5 and produced a similar pat tern. The projectile‘ has also formed a crater 6, the effect of which will presently be pointed out. , _ > ' Figure 3 ,illustratesthe. impactjat anangle of such a construction becomes too; expensive or is 55 about 45 degrees to the member ‘I... The spatter 2,406,047 3 again radiates from the point of impact but the distribution is not uniform. It is about 20 per cent in the acute angle and about 80 per cent in the obtuse angle. A similar effect occurs at 4 Figures 12 and 13 show spatter from a soft con vex surface 21 and from a soft concave surface 28. The direction of the spatter is not materially in?uenced by the shape of the surface. larger angles of incidence, such as '75 degrees to 5 Figure 14 shows the turret 30 of a‘ tank having 80 degrees from normal, as shown in Figure 4. As the angle of incidence is increasecLthe point is eventually reached at which the projectile is not broken up but simply ricochets. The an gle at which this happens is a function of the velocity of the bullet, the type and smoothness of the surface, and probably» the design of the bullet. ' The spatter pattern on face hardened surfaces is similar to that on semi-hard surfaces except where the surface is chipped by armor piercing Figuresw5" and 6 show characteristic patterns 1 a sight opening 3|. In an unfavorable design, this opening would be approximately in the up ward projection of the sloping front plate 32, since the spatter would be directed towards the opening. Figure 14 shows the plate 32 disposed at such an angle that its projection lies consid erably above the opening 3|. However, where a less favorable angle cannot be avoided, one or more angle irons 313 are secured across the front plate, as shown in Figure 15. These irons obviously de?ect the spatter before it ‘reaches the sight opening. 'If any spatter ‘should travel beneath the ?rst angle iron, it will when the plate is chipped or- ‘when the "armor ' < be stopped by the second iron. piercing core of the bullet is broken. Where this Figure 16 shows a door ‘40 closing against a wall happens, the bullet spatter from the-jacket or or plate 41, leaving an angular crack 42. Ref shell-is somewhat similar to that produced by erence to Figure 9' shows that a hit on the wall ball ammunition, skimming'along' the plate 10 would spatter through the crack. A de?ecting bead 43 near the entrance end of. the crack is useful on hard plate, throwing the surface spat as indicated by arrows. H.‘ However, the ‘core fragments and particles ofv the plate, indicated by the numeral l2, ?y off in a haphazard man ter upward. ner. It might be noted here'that' an armor pierc ing core is quite likely to shatter on striking a semi-hard surface l3 at an angleas shown in Figure ‘6, but would not do so with a'normal hit. '1 Figure 7 shows the effect ‘of a bullet striking a hard, convex surface l5 at normal‘ incidence. Whether the surface is cylindrical or spherical, ' ‘ ’ The treatment of. a direct hit at the entrance of the crack is shown in Figure 17 where a‘ door 44 similarly closes against a wall or plate 45, leaving an angular crack 146. A de?ector in the nature of a ?at strip 41 is secured to one of the walls of the crack or a prolongation thereof, forming with this wall an acute angle facing into the direction of travel. spatter entering such a the surface at the point of impact, as indicated trap loses most of its velocity because of the by the numeral l6; This is true even-if the in sharp angle of de?ection and is relatively harm cidence ‘is not radial, as indicated ‘by the nu less on leaving the trap. meral I1. Armor piercing ammunition on a hard ' Figure 18' shows an improvement of this ar surface; where the, core or plate is‘ shattered, rangement wherein the door is beveled oil" at 48 does not follow this rule.' Softer targets are dis 40 directly adjacent to the free edge of the strip cussed below. _ T 1 ' the spatter is distributedin-a plane tangent to 41'. The beveled edge de?ects the spatter back Figure 8 shows the spatter distribution result into the crack in cases where the spatter origi ing from an impact of ball‘ ammunition on a mated with sufficient energy to maintain velocity after entering the trap. Tests have shown that occasionally 1% inch stock will be blown out by direct hits. Therefore, twelve gauge stock should be used and should be carefully welded in place. The sharper the turn made by the spatter, the hard, concave cylindrical surface It. The spat ter radiates from the point of impact as for any other hard surface, but is de?ectedby the ad jacent curved surface and is substantially re versed in direction if the total ‘curvature of the surface approaches‘ 180" degrees. Centrifugal force causes the particles’to hug'the surface of the plate. 50 The concave surface is one of the most useful means of spatter control‘ if it can be ‘eco nomically incorporated in the construction. Figure 9‘ illustrates de?ection of'spatter at an intercepting surface. ‘ The spatter radiates along " the ?rst plate 20 in the manner? described. A portion striking the nearby angularly disposed vplate 2| again radiates from the‘ point of impact. Due to this ‘behavior, some of the spatter en tering a jagged path will emerge at the other 60 end of the path. The velocity is of course reduced with each impact. ‘ ' V . On softer surfaces, such ‘as cast armor and soft homogeneous plate where ball ammunition produces more or lessof a crater, the spatter pattern is influenced by that crater. The spat ter distribution on cast armor ‘plate 25 of about 300 Brinell is shown in‘ Figure 10 and on cold more energy it loses in the turn. This applies also to curved de?ecting surfaces. Figures 19 and 20 illustrate the embodiment of ‘a concave surface for de?ecting the spatter back into the general direction of origin by bypassing or re-direction. In Figure 19 a door 50 closes against'a wall or ‘plate 5!.’ A substantial space 52 is maintained between the parts, and a concave surface 53 is formed at the bottom of the space. Spatter from adirect hit at the entrance to the space is reversed or re-directed by the concave surface as shown by the arrows. _ v . In Figure 20 two parts 54 and 55 are spaced to form a slit 56. A concave surface 5'! formed on one or both of the parts adjacent to the slit throws ‘the spatter across the slit._ When the material is cast armor and produces fragments, or when armor piercing ammunition breaks up, a hit on a high point of the concave surface is likely to rolled steel plate'i?. in Figure 11. The direction throw fragment into theslit. Where this is like cluded angle, the narrower‘ is the pattern. Thus, there is less danger when a crater is formed, since a greater portion of the spatter is thrown away door is shown in Figure 21. A curved strip>58 is welded to the hull 59 at the emission‘end of the of spatter is approximately a prolongation of 70 ly, a different treatment‘ should be employed. The application of the 'involute principle to a the wall of the‘ crater, and'the smaller the in fromtheplate. . I .- ' 1- " crack 60 between the hull and the door 6|. Pare ticles ‘entering the strip are whirled and thus def 75 prived of considerable momentum. ' ' 2,406,047 5 6 Where close tolerance is not required, the con struction shown in Figure 22 may be used. The part 62 overlaps the part 63 and is formed with a this path the fragments still retain su?cient ve locity to escape with appreciable momentum, as shown by the arrows. rather large concavity 64. Opposite this, the part The foregoing illustrations and descriptions 53 is formed with a smaller concavity 65. The i) show that effective spatter traps can be built for effect of a hit at the entrance end of the space practically all structures. Although the traps is illustrated by the arrows. shown for gun rotors are not altogether effective This construction is e?ective for ball ammuni against fragments from small arms armor pierc~ tion but passes some fragments produced by ar ing ammuntion on direct hits, they undoubtedly mor piercing ammunition. It should therefore have considerable value on less direct hits. not be used Without additional protection. The e?ectiveness of the trapping within a rotor A practicable treatment of a curved path is housing depends on the dimension of the clear shown in Figure 23, between a gun rotor ‘H3 and its ance and the length of the curved path. The housing ‘I l. The spatter travels around the curve trapping is more elfective in a longer path. Small 15 and is held very close to it by centrifugal force. clearances are likely to result in locking of the A simple trap 72 is secured to the housing and rotor, due to the wedging of particles therein and forming an acute angle facing into the direction burring of the surfaces, which has the same ef of travel, serves to catch the spatter. feet. A clearance of % inch is not su?icient to Closely machined tolerances are often used to prevent locking in this manner, and a wider clear eliminate spatter. These result in slow and ex anoe is recommended for use in connection with pensive production and immobilization of the a trap. . rotor from dust, dirt, rust and burring by small Various embodiments of the invention have arms ?re. An e?ective trap permits larger tol been illustrated and described. It is to be noted erances. that the particular construction to be used should An alternative construction is shown in Figure 25 be selected in view of the nature of the apparatus 24 where the trap is in the form of an involute 73 Where it is to be installed and in the light of prin having an angularly disposed end T4. The spat ciples herein discussed. Adaptation of the trap ter entering the trap is forced into a circular or structure, indicated by these principles, may also whirling movement which reduces the velocity. be necessary. Another arrangement for a rotor is shown in What I claim is: Figure 25. A number of strips 15 are secured at A door joint comprising, in combination, a intervals to the housing, each forming an acute hatch member having a hatch way with an ar angle facing into the direction of ?re. This ar cuate shaped recess on the inner side thereof, a rangement is very eiTective in trapping all the hatch cover having an extending marginal por spatter. tion for overlapping the marginal portion of the Figure 26 is a reproduction of Figure 23 to show hatch in said hatch member when it is engaged the effect of armor piercing bullet fragments. therewith, the underside of said projecting over The fragments rebound from the armor in paths lapping portion receding into the arcuate contour designated by the arrows at. Little or no spat of a recess in the outer side of said hatch cover, ter escapes. This view illustrates the fact that 40 said arcuate shaped recess having the bottom side adequate protection may be obtained if suf?cient theerof in substantially the same horizontal plane curved surface is available. Otherwise some of with the bottom portion of the recess in the inner the particles will escape, as illustrated in Figure marginal portion of said hatch member. 27. Here the housing Tl’ provides a shorter 45 curved path than in Figure 26. At the end of WILLARD E. SWIFT, JR.