US3901124A - Tank grating - Google Patents

Abstract

A grating for use over opening means in armored cars, which grating has intercepting cup-shaped protrusions on opposite sides of the web members of said grating, in which the dimensioning of the respective local thickness of the cross sections of the rib members is effected in consideration of shelling directions which extend in a plane perpendicular to the longitudinal extension of the rib members but which otherwise extend in any direction with regard to the end face of the gratings in such a way that the path of possible shells are tangent to the front portions of the outermost end faces of the rib members while hitting side surfaces of the rib members at an angle Alpha , the applicable local steel thickness within the range of the projectile path hitting the rib members at an impact angle Alpha derived from that safety curve which in conformity with the impact angle Alpha indicates the wall thickness for that armor steel for which in conformity with the type and caliber of the projectile and of the firing weapon and the anticipated shelling distance safety against shelling is required.

Description

United States atent 11 1 [111 3,901,124 Hausenblas Aug. 26, 1975 TANK GRATING napolis, Md., 1921, p. 485. [75] Inventor: l-lelmut Hausenblas,

Kassel-Kirch i m l m y Primary ExaminerStephen C. Bentley [73] Assigneez Rheinstahl Henschel Attorney, Agent, or Firm-Walter Becker Aktiengesellschaft, Kassel, Germany [22] Filed: July 25, I973 57 ABSTRACT 1 Appl 382349 A grating for use over opening means in armored cars, R lated US. A li ti Dat which grating has intercepting cup-shaped protrusions [63] cominuafiommpan of Sen 196'154 5, on opposite sides of the web members of said grating, 1971, abandonc in which the dimensioning of the respective local thickness of the cross sections of the rib members is [30] Foreign Application p i Data effected in consideration of shelling directions which Nov 26 1970 German 2058169 extend in a plane perpendicular to the longitudinal ex- I y tension of the rib members but which otherwise ex- [52] U S Cl 89/36 109/49 5 tend in any direction with regard to the end face of [51] i 6 the gratings in such a way that the path of possible [58] Field IIIIIIIII 109/49 5 Shells are tangent to the front portions of the outerg 180/68- most end faces of the rib members while hitting side surfaces of the rib members at an angle a, the applica- [56] References Cited ble local steel thickness within the range of the projectile path hitting the rib members at an impact angle a UNITED STATES PATENTS derived from that safety curve which in conformity 3,586,236 6/1971 Schafflcr 89/36 L ith the impact ang]e indicates the wall thickness FOREIGN PATENTS OR APPLICATIONS for that armor steel for which in conformity with the l 159 816 12/963 Grman 109/495 type and caliber of the projectile and of the firing l l84 675 l2/l964 German; I:I:3:11:13: 109/495 weapon and the anticipated shelling distance Safety against shelling is required.

3 Claims, 5 Drawing Figures sum 1 o 3 PATENTEU W92 5 I975 PATENTEU AUB25|975 3,901,124

SHEET E OF 3 Fig.1 b

PATENTED AUG 2 6 I975 sum 3 u F 3 Fig.2

o impact angle 0C 0 Fig.3

TANK GRATING This is a continuation-in-part of co-pending U.S. application Ser. No. 196154 Hausenblas filed Nov. 5, 1971 now abandoned.

The present invention relates to a grating for use as tank grating having cup-shaped intercepting protrusions on its elements for blocking a rectilinear passage of projectiles, splinters or similar bodies through the grating, while the cross section of the ribs toward the outside of the grating is thicker than the further inwardly located smaller cross-sectional thickness and while the outer end face of the ribs is of an overall convex coutour and the rib cross section within the region of its smaller thickness is provided with cup-shaped intercepting protrusions extending toward different sides of the ribs.

With tank gratings of this type it is assumed that the projectiles and splinters to be blocked, unless they hit the tank perpendicularly, will impact upon the grating only at a limited relatively small angle with regard to the surface of the grating. The dimensioning is so selected that with a substantially horizontal or only slightly inclined arrangement of the grating on the armored vehicle, an energy-loaded projectile arriving at the usually maximum angle of elevation with regard to the grating surface will impact upon the thick portion of the rib cross section. However, in many instances it becomes necessary to provide gratings also on parts of the vehicle on the stern and on the side walls of the armored vehicle. Frequently the lack of space makes it necessary to place the gratings on the vehicle surface. However, the assumption that the projectiles and splinters to be intercepted hit the grating at a limited relatively small angle only with regard to the grating surface no longer applies with this arrangement. In other words, when mounted at these areas, the gratings with the usual dimensions will be pierced because the projectiles will hit at an angle which is different from the angle on which the dimensioning was based.

It is, therefore, an object of the present invention so to improve the cross-sectional shape of the grating bars as they have become known by German Pat. No. 1,159,816 that the gratings will also when shot at under any steep angle with regard to the grating surface be able to block projectiles and splinters in the same manner as the surrounding walls of the vehicle while at the same time a loss in pressure of the incoming and outflowing air will be as low as possible.

These and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawings, in which:

FIG. 1 shows a longitudinal section through an armored plate with an opening having across thereof arranged a grating according to the invention, said section being taken along the line II of FIG. la.

FIG. 1a is a top view of FIG. 1.

FIG. lb is a cross section through a grating according to the invention with three bars, said section being taken along the line IbIb of FIG. 1a.

FIG. 2 shows the principal course of a safety curve of a tank steel; the thickness d of the tank steel plate in millimeters is represented as a function of the impact angle a in degrees.

FIG. 3 is a cross section through a tank steel plate having a thickness d and having associated therewith the impact angle a on the upper surface of the tank steel plate.

The problem outlined above has been solved according to the present invention by the fact that, while maintaining the structure of the cross-sectional shape of the grating bars with outwardly located thick head portion, with adjacent rib-like extensions substantially vertically located with regard to the surface of the grating and with at least two intercepting cup-shaped protrusions according to German Pat. No. 1,159,816 provided on alternate sides of these ribs, all cross-sectional parts of the grating bars are as to their local thickness so dimensioned that they meet the requirements with respect to the minimum values as listed in the so-called safety curves for tank steel sheets, while, to take into consideration the severest conditions, shelling directions are assumed which extend in a plane perpendicular to the longitudinal extension of the grating bars, but which otherwise extend in any desired direction with regard to the end face of the gratings, and while the projectile paths are tangent to the front portion of the bar head portions. Inasmuch as the safety curves, in addition to the quality of the tank steel, also depend on the caliber and the type of the impacting projectiles as well as on the fighting distance, in each instance that particular curve for the quality of the tank steel to be used is to be employed for the dimensioning which corresponds to the respective type of projectile, caliber and fighting distance against which the tank grating is to be safe-guarded.

A particularly advantageous design of the grating according'to the present invention will be realized by making the thickness of the head portions of the grating bars measured in the direction of the grating surface, in a manner known per se, substantially equal to half the pitch of the grating bars, and by selecting the width of the cup-shaped intercepting protrusions as measured parallel to the surface of the grating in such a way that it will be impossible in any shelling direction to place a straight line as tangent to the cross section of the bars which line will not at any other place intersect or at least be tangent to the contour of another portion of a cross section of a bar.

By the selection according to the present invention of the ratio of the thickness of the head portions to the pitch of the grating bars it will be assured that the projectiles, which arrive at steeper angles with regard to the surface of the grating and which hit the grating bars below their head portions, will hit the surface of the bars at relatively flat angles so that in conformity with the above referred to safety curves relatively thin material thickness will suffice to prevent a piercing. In this way a particularly favorable weight of the grating is obtained.

For keeping out liquid, burning substances, especially chemical warfare agents, it is suggested according to a further development of the present invention to provide the lateral confining walls of the grating with discharge openings which originate at the cavities of the cup-shaped protrusions and which discharge such substances to the outside of the vehicle. If it is desired to realize as slight a loss in pressure as possible of the air or gas passing through the gratings, the cup-shaped protrusions are to be filled in with a filling substance which is mechanically less resistant so that splinters can without difficulties enter into the filling substance and are retained therein.

According to a further development of the invention, the surface of the filling substance may be painted in such a way that an as smooth as possible surface is obtained which will result in the lowest possible friction losses for the air passing through.

Referring now to the drawings in detail, FIG. 1 shows an armored plate 100 with an opening 101 across which extends the grating according to the invention which grating comprises a plurality of grating bars a cutout of which only with the bars 102, 102', 102" and 102" being shown. These grating bars, the cross section of which is illustrated in FIG. 1b, are connected to the frame parts 103, 103 at 104, 104', 104" and 104" by zinc plating and welding. If desired one or more intermediate supporting bars 105 or the like may be provided to which the grating bars are likewise connected by zinc plating and welding. The connection of the grating to the armored plate 100 is effected by means of the frame bars 103, 103' of said armored plate. To this end there is provided a hinge which comprises an element 107 welded to the frame part 103, the elements 108, 108 welded to the armored plate 100, the bolt 109, and the cotter pin 110. On the other side the grating is connected to the armored plate 100 by means of an element 111 which is welded to the frame part 103' and has a bore 11 1a through which passes a screw bolt 112 threaded into a threaded dog 113 which is welded to the armored plate 100.

As will be seen from FIG. 1b showing the tank grating of the invention in cross section with a head edge portion 1, the bars of the tank grating are provided with a rib-like extension 2 substantially perpendicular to the grating surface 3 while two intercepting cup-shaped or hook-shaped in cross section protrusions 4 and 5 are arranged alternately on opposite sides of the ribs. Lines 6 and 7 represent projectile curves of all possible directions or angles ,8 which in each instance are tangent to the thick head 1 of the grating bars and which then within the grating impact upon the surface of the bars at different angles a. In other words, the angles B indicate the flight path of the projectile relative to the surface of the grating.

The known definition of the impact angle a between the direction of the projectile curve 10 and the surface of the tank plate 11 with the thickness d is illustrated in FIG. 3. FIG. 2 shows the basic form of the known safety curves which indicate the minimum thickness d of the tank steel plate depending on the impact angle a which thickness is necessary to prevent the piercing of the tank steel plate of a certain tank steel thickness, for a certain projectile caliber, for a certain type of projectile, and at a certain fighting distance. Wherever the surface of a grating bar is hit in conformity with the projectile curves 6 and 7, the thickness d of the tank material therebehind is, according to the present invention, depending on the local impact angle a to be dimensioned in such a way that the safety requirements of FIG. 2 are met in conformity with the given values of the above referred to parameters of HG. 2. The thickness of the ribs is provided by inclining the surface of the rib having the hook-shaped protrusion 4 from the head edge portion 1 to the protrusion, while the opposite surface is similarly inclined from the head edge portion and then inclined away from the first surface to the hook-shaped protrusion 5.

Such safety curve, which is obtained by the shelling of tank steel plates, can approximately be expressed by the equation d do X sin a, in which do is a constant depending on the quality of the respective tank steel and the above referred to parameters. The range in which this curve applies relates to the customary values of a only. If all values of a are to be covered for certain calibers,'types of projectiles and fighting distance, this curve is ascertained from shelling tests.

Additionally, linings 8 and 9 illustrated in FIG. 1b by dot-dash lines and consisting of a light filling substance of low mechanical resistance may be provided which will not affect the guide lines for the dimensioning of the steel cross section and which may aid the requirement concerning splinter safety and low pressure loss. Such linings may consist of a strip of synthetic material, e.g. foamed synthetic material such as foamed rubber material, of a synthetic mass such as polyurethane, adapted to be applied by painting or spraying. The synthetic strips may be connected to the steel grating bars by any suitable synthetic adhesive or cement, whereas the synthetic mass itself has adhesive properties so that it adheres by itself to the walls of the gratings to which it has been applied.

There is noted a foreign German Pat. disclosure No. 1,184,675 which actually concerns an addition to a foreign German Pat. No. 1,159,816 belonging to the assignee of the present invention. According to the additional patent disclosure of German Pat. No. 1,184,675 the cup-shaped protrusions with the grating used as armor grating becomes filled-out with a filling mass that is relatively light and capable of little resistance mechanically.

Nothing is mentioned in the additional patent about the structuring of the ribs (grating webs) consisting of armor steel. The parent German Pat. No. 1,159,816 includes in contrast as teaching the statements about the suitable constructive embodiment of the grating webs. Because of the predetermined utilization of these gratings at that time upon the roof of a vehicle there only would have to be considered elevational angle of the arriving shots with respect to the grille or grating upper surface up to only a relatively low boundary value. These shots accordingly always only hit upon the thick head portions of the grating webs; for this reason in the corresponding patent disclosure there was provided only a corresponding predetermined dimensioning of the thickness thereof in order to hinger the penetration of the head portions of the webs or struts. For the ribformed web parts lying below the head portions and at locations adjoining the adjacent cup-shaped projections which formerly could be hit only by shrapnel or shot splinters, no further features were prescribed about the formation thereof in addition to the disclosure already given because of the essentially smaller energy of these splinters. After subsequently the gratings had to be used on more or less vertical vehicle walls, for instance as rear-cover gratings, the aforementioned limits as to the elevational angle of the arriving shots no longer applied which means that the grille or gratings could be shot upon as far as a location at right angles to the upper surface thereof. Now the rib-type portions and the cup-shaped protrusions could be hit not only by splinters of shots damaging the head portions but rather also by shots arriving directly with full energy (not dispersed or split up). Consequently the concern no longer involved the form of the rib-formed and cupshaped protrusion in contrast to the statements of the prior foreign German disclosure No. 1,159,816, but

rather also the concern must be emphasized as now being with the not-mentioned dimensioning of these web portions. For this reason the present disclosure includes and covers the dimensionally prescribed measures for the entire portions collectively.

The features of the present invention are given without fixing or restricting the same to a particular caliber, speed and type of the arriving shots as well as the quality of the armor steel used for the grating webs or struts to the extent possible. These paraticularly are the parameters upon which the mentioned safety characteristic or curves for armoring would be dependent.

The foreign German disclosure No. 1,114,410 describes a cover grating or grille for cooling air openings with an armored military vehicle, This known cover grille or grating consists of a number of scale-like or shed-type baffles or sheet metal deflectors of armor steel engaging over each other whereby each baffle or deflector plate has both a dome or peak and also a cup or shell adjoining therewith. Hereby the concern, however, is with a roof of a vehicle having a cover grille or grating arranged therewith as can be recognized especially from the illustration of FIG. 7. At most the earlier embodiment would have outlet openings with the cover grille or grating which would seem similar to those of the present disclosure.

The grating webs with the prior German disclosure No. 1,159,816 are so embodied that the shots arriving at different angles (as far as to the mentioned boundary value of the shown angle) directly always only hit the compacted head portion of the grating web whereby the shots split up and splinter into various directions. Thus as mentioned previously the rib-formed portions with the cups or catching shells located below the head portions could now only be met by shot splinters. Since splinters are known to have considerably less penetrating capability than shots that are not split up, the ribformed portions and the cups or catching shells of the grating webs were dimensioned to be more weak and not according to the safety curves or characteristics that apply for shots that have not been split up.

Rear cover grilles or gratings in contrast to roof gratings for instance can be subjected to shots which will hit more or less at right angles to the surface thereof so that these rear grilles or gratings also must be made safe, consequently the ribformed parts of the grating webs or struts can be hit together with the catching shells or cups by shots that are not split up; since the same can be hit now not only by shots that have been sg i t up but rather by direct hitting shots, it becomes necessary in contrast to the statements of the German disclosure No. 1,184,675 to embody the rear grille or grating in according with the features of the present invention. The present case discloses how the same should be embodied to comply with the safety curves or characteristics. This represents an essential part of the teaching of the present invention and cannot be disregarded as being unessential and without purpose.

In summary, there can be noted that the essential concept of the present invention that the grating or grille was provided at the vehicle rear should be embodied aside from the vehicle roof so that also for shots encountered at every suitable steep angle for grating or grille upper surface protection will be provided.

The gratings used for covering up openings in armored vehicles consists in essence of ribs having profiled cross section and these hindering straight-line passage of shots, splinters and the like. A possibility exists that shots fly closer to the head part of the grating webs whereby material is struck out of the head part. Thus the features concerning the described tangential relationship and the like of shot paths can be considered to be an essential factor influencing the requirements for safety of the grating believed to possess inventiveness in a general sense.

The safety characteristics or curves taken into consideration as far as known to be pertinent to armor steel plates are implicitly pertinent to a precondition of constant plate thickness as to the part subject to being hit by shots. The corresponding characteristic or curves for armor-steel casting are also applied only for very conventional armor thickness conditions. With the grating webs or struts according to the present invention in contrast the dimensional wall thicknesses change very quickly as shown by FIG. 1 of the drawings. There occurred accordingly the question whether the angle of impact relative to the steel outer surface hit by the shot or relative to the middle line of the steel thickness should be counted. While with conventional wall thicknesses there can be neglected any changes in the difference thereof with respect to both angles, the same is no longer true for the present case. The fixing of the measurement of the angle relative to the hit steel armor surface proceeds from the concept that the penetrating procedure of the shot becomes determined in essence from the first phase thereof, in other words, shortly after impact of the shot. Such consideration involves an inventive feature which would not be obvious and in a desirable sense and for partial compensation of the consequences with respect to the strict safety requirements set forth previously would lead to thinner steel cross-sectional thickness and therewith result in a lighter embodiment of the grating webs or struts. Test results have shown that grating webs or struts so dimensioned are not embodied too weak with respect to the ballistic protection.

In order to hinder that shots or splinters repelled by the ribs will penetrate into the vehicle inner chamber, there is already known in the German disclosure No. 1,159,816 to provide a particular cup-shaped configuration of the ribs of the grating; and the further cited foreign German disclosure No. 1,184,675 shows filling out of the cup-shaped configurations with toughresilient work material as an additional splinter protection. With the cited foreign German disclosure No. 1,159,816, it is apparent that the thinner grating web or strut cross-sections apparently are not dimensioned according to the teaching of the present invention as readily recognizable from a comparison of the representation of what is known with respect to the teaching of the present invention. This was also not necessary with the prior embodiment since at that time the thinner grating web or strut parts in view of the precondition that shots are to be expected only at a predetermined angle relative to the grille or grating outer surface was such that the same would be struck only by splinters at the head portion of the grating webs or struts when shattered shots were to be taken into consideration only for protective purposes whereas now direct shots that are not shattered or splintered are thereby taken for protective purposes. A grating with grille or grating webs or struts according to the present invention is to hinder penetration of shots, shot splinters and the like into the vehicle interior both during direct flight and also during rebound or ricochet conditions regardless of the direction from which these foreign bodies come and on the other hand the same are to provide the smallest possible flow resistance as to passage of air there-through.

Thereby that there is hindered that the shots or splinters can penetrate the grating during direct flight or during repelling (the shots or splinters would for instance have to be repelled twice, one after the other) the effectiveness of the same in general should be very much weakened since the remaining energy of the shots or splinters becomes destroyed. Advantageously there is also effected that the grating is embodied in a technically simple manner to produce and having a weight-saving formation whereby also the danger of an undesired reduction of air passage therethrough becomes extensively avoided.

In summary, there can be noted that there is provided a cover grille or grating to be used as armor for openings on armored vehicles. The axially parallel struts or webs of the grille on the side away from the vehicle each have a thickened head embodied on the face surface; adjoining thereto the same rib-formed extensions or protrusions are located substantially at right angles to the grille outer surface and on both sides providing cup-shaped or catching shell portions which suitably are filled out with tough resilient work material as additional splinter protection. Thereby the foregoing is further characterized in that the spacing of the grating webs or struts located substantially horizontally in the vehicle rear portion becomes so selected with respect to each other under consideration of the shot paths (6, 7) of a direct or repelled flight for a shot, foreign body and the like encountered thereby such that the flight path in every case is blocked by one of the rib-formed protrusions or extensions (2) of one of the grating webs or struts. The foregoing takes into consideration a plane located at right angles to the grating web or strut longitudinal direction but otherwise the same extended in suitable direction with respect to the grille outer surface (3) that the shot paths (6, 7) are tangential to the heads (1) of the grille or grating struts or webs and the rib-formed protrusion or extension of each grating strut or web provides a thickness (d) dependent upon impact angle (alpha) between the shot path (10) and the grating strut or web.

It is, of course, to be understood that the present invention is, by no means, limited to the particular showing in the drawings but also comprises any modifications within the scope of the appended claims.

What I claim is:

1. A grating for protecting openings in the sides and ends of armored vehicles, which includes a plurality of rib members arranged in parallel, spaced relation to each other and perpendicular to the grating surface, said rib members being thickest at the head edges adjacent said surface of said grating and substantially as thick as the spacing between said head edges portions, each of said rib members having a protrusion hookshaped in cross section on one surface at its central intermediate portion-and a second protrusion hookedshaped in cross section on the other surface at the edge opposite said head edge portion, each of said protrusions forming a channel opening toward said head edge portion, said other surface being curved from said head edge portion to said intermediate portion and then inclined from said intermediate portion away from said one surface to said hook-shaped protrusion at the opposite edge, said one surface being inclined from said head edge portion in the same direction as said other surface to said intermediate protrusion, said intermediate protrusion of each of said rib members extending to a transverse plane passing through the surface of the head edge portion of an adjoining rib member, said intermediate protrusion being substantially equal in thickness to the thickness of said intermediate portion of said rib member, said head portion, intermediate portion and protrusions being of a thickness at every point of impact of missiles as to provide resistance to penetration at the maximum angle of impact according to a curve of the maximum thickness for resistance to penetration at the maximum angle of impact of a missile at that point.

2. A grating in combination according to claim 1, which comprises outlet openings in the lateral confinements of said grating, said outlet openings extending from the cavity of said intercepting hook-shaped protrusions in the direction toward the exterior of the armored vehicle.

3. A grating in combination according to claim 2, in which said intercepting hook-shaped protrusions are lined with a low-weight filling mass of synthetic foam with low mechanical resistance adhering thereto.

Claims (3)

1. A grating for protecting openings in the sides and ends of armored vehicles, which includes a plurality of rib members arranged in parallel, spaced relation to each other and perpendicular to the grating surface, said rib members being thickest at the head edges adjacent said surface of said grating and substantially as thick as the spacing between said head edges portions, each of said rib members having a protrusion hookshaped in cross section on one surface at its central intermediate portion and a second protrusion hooked-shaped in cross section on the other surface at the edge opposite said head edge portion, each of said protrusions forming a channel opening toward said head edge portion, said other surface being curved from said head edge portion to said intermediate portion and then inclined from said intermediate portion away from said one surface to said hook-shaped protrusion at the opposite edge, said one surface being inclined from said head edge portion in the same direction as said other surface to said intermediate protrusion, said intermediate protrusion of each of said rib members extending to a transverse plane passing through the surface of the head edge portion of an adjoining rib member, said intermediate protrusion being substantially equal in thickness to the thickness of said intermediate portion of said rib member, said head portion, intermediate portion and protrusions being of a thickness at every point of impact of missiles as to provide resistance to penetration at the maximum angle of impact according to a curve of the maximum thickness for resistance to penetration at the maximum angle of impact of a missile at that point.

2. A grating in combination according to claim 1, which comprises outlet openings in the lateral confinements of said grating, said outlet openings extending from the cavity of said intercepting hook-shaped protrusions in the direction toward the exterior of the armored vehicle.

3. A grating in combination according to claim 2, in which said intercepting hook-shaped protrusions are lined with a low-weigHt filling mass of synthetic foam with low mechanical resistance adhering thereto.

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