Propagation of detonation between pallets of munition such as artillery sls is prevented by interposing an inert material having adequate density to render the fragments from a detonating pallet non-lethal when they reach explosive devices in a neighboring pallet. The material must be of a type which does not itself form lethal fragments and the material must be placed sufficiently close to the explosive devices that the fragments from an explosive have not had time to separate into individual pieces but, instead, produce a plate impact on the material. This latter requirement reduces or eliminates the need for any substantial strength in the material.

BACKGROUND OF THE INVENTION 
The present invention is related to apparatus for reducing the propagation 
of explosion from one explosive device to another. In particular, the 
present invention is related to the prevention of the propagation of 
explosion from explosive devices in one pallet to other explosive devices 
nearby. 
Munitions are classified according to the damage which can result from 
accidental or untimely explosion thereof and their susceptibility to 
untimely or accidental detonation due to impact thereon by fragments 
produced by a nearby explosion. One of the especially hazardous catagories 
is the "mass detonating" class of munitions wherein detonation of one 
munition in close proximity with other similar munitions will cause most 
or all of the others to detonate. 
U.S. Pat. No. 4,222,484 addressed the problem of preventing the detonation 
of a second munition packed on a pallet with an exploding first munition. 
This patent disclosed the use of a coherent solid mass of 
vibration-damping and moisture-resisting material positioned between 
munitions on lines joining the centers or axes thereof. This material 
interrupted transmission of shock effects to reduce a likelihood of mass 
detonation of all of the explosives packed together on a pallet. 
When adjacent munitions on a pallet detonate, a focused jet of lethal 
particles is formed in a symmetry plane between the munition. This focused 
jet, similar in its effects to a shaped charge munition, greatly enhances 
the lethality of particles emerging from a plurality of detonating 
explosive devices on a pallet. The mass focusing in the symmetry plane of 
detonating 155 mm shells, for example, is capable of perforating in excess 
of 3.5 inches of rolled homogeneous armor plate. 
Thus, the two problems to be solved by the present invention include the 
detonation of munitions in a nearby location from primary fragments of one 
or more exploding munitions on a pallet as well as the even more severe 
threat to nearby munitions of a mass focused jet resulting from the 
simultaneous or near-simultaneous detonation of two munitions on a pallet. 
OBJECTS AND SUMMARY OF THE INVENTION 
Accordingly, it is an object of the present invention to provide apparatus 
for preventing the detonation of explosive devices due to detonation of 
one or more munitions on a nearby pallet. 
It is a further object of the invention to prevent the detonation of 
explosive devices due to the mass focusing of fragments resulting from 
interaction of simultaneously or near-simultaneously detonating munitions 
in a nearby pallet. 
It is a further object of the invention to provide apparatus for preventing 
propagation of explosion between pallets which is compact, lightweight and 
low cost. 
It is a further object of the invention to provide a shield for preventing 
propagation of detonation of explosives between pallets without requiring 
modification to existing pallets. 
According to an aspect of the present invention, there is provided a 
shielding apparatus for a plurality of munitions assembled together into a 
unit, comprising at least a first shield, the first shield containing a 
material having an areal density high enough to render fragments from the 
plurality of munitions non-lethal to nearby munitions, the material being 
incapable itself of forming lethal fragments, and the shield being 
disposed at distances close enough to at least two adjacent ones of the 
plurality of munitions that fragments from detonation of one or more of 
the at least two adjacent ones impact the shield in a plate-like impact. 
The above, and other objects, features and advantages of the present 
invention will become apparent from the following description read in 
conjunction with the accompanying drawings, in which like reference 
numerals designate the same elements.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to FIG. 1, there is shown adjacent cylindrical munitions 10 
and 12 which may be, for example, 155 mm artillery shells. As 
conventionally packed for storage and shipment, munitions 10 and 12 are 
disposed in a pallet (not shown in FIG. 1) with their tangent points 14 
touching or near-touching. 
If munitions 10 and 12 detonate simultaneously or near-simultaneously, a 
mass focused jet of particles is expelled along a symmetry plane 16 which 
greatly enhances the destructive effect of the explosion of both of 
munitions 10 and 12 as compared to the individual explosion of either one. 
Referring now to FIG. 2, there is shown, generally at 18, a conventional 
pallet containing eight munitions 20 which may be, for example, 155 mm 
shells disposed on a lower platform 22. Platform 22 may be of any 
convenient material but, as is conventional, it is preferably fabricated 
of wood. Shells 20 are disposed parallel to each other with their tangent 
points touching or nearly touching adjacent munitions. As is conventional, 
wooden feet 24 and 26 are attached to the underside of platform 22 to 
enable a lifting device such as, for example, a lifting fork, to be 
inserted under pallet 18 for handling thereof. 
A retainer plate 28 is disposed at the top end (the forward end of the 
ogive) of munitions 20 and preferably includes openings 30 through which 
the extreme forward end 32 of munitions 20 may partly protrude for 
stabilization thereof. Lifting rings 34, conventionally provided with 
large munitions 20 are permitted to protrude beyond openings 30. 
Platform 22 and retaining plate 28 are clamped in locked condition with 
munitions 20 using conventional bands 36. 
As above described, pallet 18 is conventional in the art with adjacent 
munitions retained in the positions shown with tangent points 14 of their 
widest parts touching or near-touching. 
Referring again to FIG. 2, four shields 38, 40, 42 and 44, are assembled 
fitting against the four lateral sides of platform 22 and the retainer 
plate 28 to form a substantially continuous shield about the sides and 
ends of pallet 18. Shields 38, 40, 42 and 44 are installed in place in any 
convenient manner but, in the preferred embodiment, are secured in place 
by a plurality of bands (not shown) corresponding to bands 36 which 
encircle them. Preferably, a pair of bands (not shown) are wrapped about 
and secure opposed shields 40 and 44 to opposed sides of pallet 18 and a 
similar treatment is given to opposed shields 38 and 42. 
Although four shields 38, 40, 42 and 44 are shown encircling a single 
pallet 18 in FIG. 2, it should not be assumed either that full lateral 
shielding is always required nor that a shielding arrangement is limited 
to a single pallet. For example, if the warehousing arrangement permits 
it, shields may be required only on one pair of opposed sides to protect 
munitions stacked 180.degree. apart. Further, two or more pallets 18 may 
be assembled into a single shielded assembly with shields 38, 40, 42 and 
44 disposed about the two-pallet or larger assembly. 
Referring now to FIG. 3, a two-pallet shielded assembly 46 is shown in 
which a first pallet 18 and a second pallet 18' is encircled by shields 
38, 40, 42 and 44. Transverse strapping bands 48 and 50 hold shields 40 
and 44 against opposed sides of pallets 18 and 18' as well as holding 
pallets 18 and 18' together in a single unit. Tangential bands 52 and 54 
encircle all four shields 38, 40, 42 and 44 thus holding all shields in 
place as well as enhancing the unification of pallets 18 and 18'. 
Returning now to FIG. 2, each of the shields such as, for example, shield 
38 includes a core 56 having a sufficient areal density and thickness to 
render primary fragments from individual rounds as well as the mass 
focused jet caused by the interaction of adjacent rounds non-lethal to a 
mass detonating class of munitions spaced a predetermined distance away. 
An external cladding 58 and an internal cladding 60 retain and protect 
core 56 from abrasion. As will be explained, neither cladding 58 and 60 
nor core 56 requires a great amount of strength. Core 56 need only have 
sufficient areal density and be of a material which breaks into non-lethal 
pieces. In the preferred embodiment, commercially available gypsum board 
normally used for interior walls has been used in core 56. A thickness of 
about three inches or less is satisfactory to prevent detonation of nearby 
munitions when probably installed. Cladding 58 and 60 may be any 
convenient material having sufficient abrasion resistance such as, for 
example, plywood, fiber board, cardboard, and the like. External cladding 
58, in particular, must be capable of resisting abrasion and breakage. 
Internal cladding 60 may be of the same or a different material. 
Referring again to FIG. 1, the applicant has discovered that the shields 
must be positioned within from about 1.2 to about 1.8 radii R of the axes 
of munitions 10 and 12 in order that the expanding casing has insufficient 
time to break up into separate fragments. This applies also to the 
interacting fragments along symmetry plane 16. Since the impact on the 
shields is a plate impact, high tensile strength of the shields is not 
required. Instead, the shields need only have sufficient areal density and 
be incapable of themselves breaking into lethal fragments. These 
requirements are satisfied by conventional gypsum board or other 
conventional materials. 
Returning to FIG. 2, it would be clear that, although shields 38, 40, 42 
and 44 may be placed very close to, or touching, munitions 20 at their 
widest points, they are spaced substantially further away at the forward 
ends 32. This may be satisfactory since the focused jet along the symmetry 
plane becomes less well developed due to the greater separation between 
the surfaces of the munitions in this region. 
It would be clear to one skilled in the art that shields for other size 
munitions may be appropriately scaled in thickness according to the above 
teachings for a particular case. 
Having described specific preferred embodiments of the invention with 
reference to the accompanying drawings, it is to be understood that the 
invention is not limited to those precise embodiments, and that various 
changes and modifications may be effected therein by one skilled in the 
art without departing from the scope or spirit of the invention as defined 
in the appended claims.