U.S. patent number 3,637,449 [Application Number 04/800,971] was granted by the patent office on 1972-01-25 for process for preparation of missiles.
This patent grant is currently assigned to FMC Corporation. Invention is credited to Harry Raech, Jr..
United States Patent |
3,637,449 |
Raech, Jr. |
January 25, 1972 |
**Please see images for:
( Certificate of Correction ) ** |
PROCESS FOR PREPARATION OF MISSILES
Abstract
A method, or process, is disclosed of preparing flechettes in
packs for insertion in a projectile, and a flexible web of
flechettes, which is formed during the process, is also disclosed.
In preparation of the pack, the flechettes are initially arranged
on a rack in an interdigitated array, and a soluble, elastic
adhesive is applied, in strip form, to the array. After the strips
of adhesive are melted into the array, a flexible web is formed
which can be removed from the rack. The web is folded into a mold
with an internal cavity in the shape of a pack suitable for
insertion into a projectile. A solvent is passed through the mold
to dissolve the adhesive, and a matrix material is introduced in
liquid form into the mold. The matrix binds the flechettes into a
frangible pack which is then installed in a projectile.
Inventors: |
Raech, Jr.; Harry (San Jose,
CA) |
Assignee: |
FMC Corporation (San Jose,
CA)
|
Family
ID: |
25179850 |
Appl.
No.: |
04/800,971 |
Filed: |
February 20, 1969 |
Current U.S.
Class: |
156/305;
102/703 |
Current CPC
Class: |
F42B
12/32 (20130101); Y10S 102/703 (20130101) |
Current International
Class: |
F42B
12/02 (20060101); F42B 12/32 (20060101); F42b
013/32 () |
Field of
Search: |
;102/38,42,DIG.7,93.4,93,67,34.4 ;43/18B ;156/296,305 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Stahl; Robert F.
Claims
What I claim is:
1. The method of preparing a plurality of flechettes for use as
missiles comprising the steps of arranging the flechettes in a
closely spaced array, applying a removable adhesive to the array of
flechettes to hold the flechettes together for handling, placing
the flechettes into a rigid receptacle of desired conformation, and
removing said adhesive.
2. The method of preparing a plurality of flechettes for use as
missiles comprising the steps of arranging the flechettes in a
closely spaced array, applying a soluble adhesive to the array of
flechettes to bind the flechettes together for handling, placing
the bound array of flechettes into a mold of desired conformation,
and dissolving the adhesive.
3. The method of preparing a plurality of flechettes for use as
missiles comprising the steps of arranging flechettes in an
interdigitated single layer array, applying a strong, soluble,
elastic adhesive to said array to bind the flechettes into flexible
webbing, placing a plurality of sections of webbing into a mold to
produce a pack of flechettes of desired conformation, and
introducing a solvent into the mold, to dissolve the adhesive.
4. The method of claim 3 including the additional step of
introducing a frangible matrix into the mold to bind the flechettes
into a frangible pack.
5. The method of claim 4 including the additional step of placing
the frangible pack into a projectile.
6. The method of preparing a plurality of flechettes for use as
missiles comprising the steps of arranging the flechettes in
closely spaced array, applying an elastic adhesive to said array to
bind the flechettes into flexible webbing, placing the webbing into
a casing, and dissolving the elastic adhesive.
7. The method of claim 6 including the additional step of
introducing a matrix material into the casing to produce a pack of
flechettes.
8. The method of claim 7 including the additional step of inserting
the casing into a projectile.
9. The method of claim 6 including the additional step of
introducing a frangible matrix material into the casing to produce
a pack of flechettes, removing the pack of flechettes from said
casing, and inserting the pack of flechettes into the
projectile.
10. The method of preparing flechettes having noses and vaned tails
for handling comprising the steps of arranging the flechettes in
rows, displacing every other flechette in a row to overlap the tail
thereof with the nose of alternate flechettes in the adjacent row,
and applying adhesive to hold the flechettes together.
11. The method of claim 10 in which the adhesive is applied in
strips to each row.
12. The method of claim 20 in which the strips of adhesive are
melted to flow onto and between the flechettes of each row.
Description
BACKGROUND OF THE INVENTION
The present invention relates to the installation of flechettes
into a projectile such as an artillery shell.
It is known to install flechettes in a projectile, such as an
artillery shell, for dispersion upon explosion of the shell.
Frequently, the flechettes are woven together with thread. The
thread, however, has a tendency to prevent complete dispersion of
the flechettes. Sometimes, the flechettes are assembled in the form
of a frangible pack which is convenient to handle and install in
the projectile. The pack will readily shatter on explosion of the
shell, and the dispersion of the flechettes will not be impaired.
In either case, however, it is difficult to handle the small
flechettes as they are being prepared in a suitable form for
assembly into the shell.
SUMMARY OF THE INVENTION
In the present invention, the flechettes are prepared in a
convenient manner for easy handling, by forming an elastic flexible
web thereof, as they are put into a form for installation in a
projectile.
In brief, in the preferred form of the invention, the flechettes
are first arranged in an interdigitated array, in a single layer,
on a rack. Strips of hot melt elastic adhesive are laid on the
array, and the adhesive is then melted to bind the flechettes into
a flexible web which can be folded into any desired conformation.
The web is not, however, installed in the projectile at this time
since the adhesive would prevent complete dispersion of the
flechettes. Instead, the web is placed in a mold, and a solvent is
passed through the mold to dissolve the adhesive. Thereafter, a
matrix material is poured into the mold. This material solidifies
into a frangible matrix which holds the flechettes in the shape
established by the mold. This frangible flechette pack is then
installed in the projectile.
It is therefore one object of the present invention to provide a
method for assembling flechettes in an easily handled form for
preparation of the flechettes for assembly into a projectile.
It is another object of the present invention to provide a method
for preparing flechettes for a projectile in which the flechettes
are temporarily bound with an adhesive.
It is yet another object of the present invention to temporarily
bind flechettes into a convenient form with a soluble adhesive for
insertion into a mold where the adhesive is dissolved and the
flechettes are formed into a pack of desired shape.
It is still another object of the present invention to produce a
flexible web of flechettes held together by an elastic band for
easy and convenient handling of the flechettes in producing a pack
of flechettes for a projectile.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a flow chart of the steps of the preferred form of the
present invention;
FIG. 2 is a view, in perspective, of the rack on which the
flechettes are arranged, with some flechettes arranged thereon in
interdigitated relationship;
FIG. 3 is an enlarged plan view of flechettes as arranged on the
rack;
FIG. 4 is a view taken on the line 4--4 of FIG. 3;
FIG. 5 is a view in perspective of the web of flechettes formed on
the rack;
FIG. 6 is a view in perspective of the mold into which the web is
folded;
FIG. 7 is view in perspective of the mold, with a manifold head and
back, and of apparatus to circulate solvent through the mold;
FIG. 8 is a view in elevation of the application of a matrix
material in liquid form to the mold;
FIG. 9 is a view, in perspective, of four frangible packs of
flechettes as taken from the mold, spaced apart for clarity;
and
FIG. 10 is view, in elevation, with parts broken away, of an
artillery shell with an internal cavity to receive the four
frangible packs of flechettes of FIG. 9, in side-to-side contact,
therein.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A method of preparing the flechettes in the form of a pack for
insertion into a projectile is shown in FIG. 1. A rack 10, as shown
in FIG. 2, has an inclined upper surface 11 with grooves 9 therein.
As shown in FIGS. 1 to 4, flechettes 12 are placed on the rack in
seven rows 13a, 13b, 13c, 13d, 13e, 13f, and 13g. Each flechette 12
is made of steel and has a pointed nose 12a, a body or shank 12b,
and a four-vaned tail 12c. The flechettes in each row are staggered
so that the tails 12c of every other flechette extend beyond the
tails of the alternate flechettes, and the tails of the alternate
flechettes rest against the body of adjacent flechettes in
interdigitated relation. It will be noted that there is a groove 9
for each row of flechettes to receive the vaned tails of the
flechettes, and that the grooves are wide enough to accommodate the
staggered tails.
The flechettes are placed in the rack to all face in the same
direction and with the vanes at 45.degree. from the horizontal and
vertical, as shown in FIGS. 3 and 4. It will be noted that the
staggered flechettes of one row are in interdigitated relation with
the flechettes of an adjacent row. For example, the noses of the
flechettes in row 13b are contiguous with the tails of the
flechettes in row 13a, so that the nose of every other flechette in
row 13b extends between the tails of alternate flechettes in row
13a. The flechettes can be placed in the rack manually or
mechanically by the use of feeding devices such as vibrators which
cause the flechettes to travel down the grooves in the rack in
regular interdigitated rows.
After (or during) the placement of the flechettes on the rack, the
flechettes are cemented together. A soluble adhesive is deposited
on the flechettes, either over the entire upper surface of the
array, or preferably, along a band A on each row. Cementing can be
accomplished by the application of a rubber adhesive, by a
plasticized adhesive such as vinyl plastisol, by a thermosetting
adhesive such as epoxy or phenolic-polyvinyl butyral, or by a hot
melt adhesive such as a polyamide. In the cases of the
thermosetting and hot melt adhesives, the application may be by
means of a tape thermally fused in place. In all cases, the glue
may be applied in the liquid phase. In all cases also it is
desirable that the adhesive have the properties of good adhesion to
steel, elongation in the range 50-200 percent, and good solvency in
solvents such as water, benzene or acetone. It has been found that
the hot melt adhesive offers the best combination of physical
properties and processability. This adhesive may, for example, be
adhesive 74 DPN- 1 of ADHESIVE PRODUCTS, Albany, Calif. The
adhesive, which is available in chunks, is melted, and then cooled,
to form a thin flat sheet. Strips S are cut from the sheet and
placed on the flechettes to cover band A, as shown in the rows of
FIG. 1. The rack is then placed in an oven 14 (FIG. 1) to melt the
strips of adhesive and bind the flechettes together.
The adhesive solidifies in elastic form to permit flexing of the
rows, and the rows are mechanically locked together because of the
manner in which alternate flechettes extend between cemented
flechettes of an adjacent row. Thus, a flexible web 15 is formed
which can be handled, as shown in FIG. 5, and folded.
The web 15 is then folded into the bottom 20 of a mold 21 as shown
in FIG. 6. The bottom 20 has an internal cavity 20a which is as
long as the web is wide. The web fills the mold cavity 20a and the
top 22 of the mold, which has an internal cavity 22a, is then
bolted to the bottom of the mold to close the mold. The internal
cavity of the closed mold, made up of cavities 20a and 22a, has a
cross section in the form of a segment of an annulus. The flechette
web 15 is folded to conform to the shape of the internal cavity of
the mold.
The adhesive bond is then removed from the web. This may be done by
simply submerging the mold in a container of solvent. Preferably,
the adhesive is removed by flushing the solvent through the mold
under pressure, preferably at an elevated temperature to speed
dissolving. To this end, as shown in FIG. 7, a manifold head 23,
having a plenum chamber 24, is secured to the mold 21 by bolts 25.
Ports 26 connect the chamber 24 with the interior cavity of the
mold. A pump 27 has a discharge port 28 connected to the chamber 24
by conduit 29. Conduit 30 extends through a manifold head 23, which
is secured to the mold opposite the other manifold head, and is in
communication with the internal cavity of the mold. Conduit 30
leads to a tank 32 of benzene, which is heated by heating coil 33.
A conduit 34 connects the benzene tank to the inlet port 35 of the
pump 27. Thus, hot benzene can be circulated through the mold to
dissolve the adhesive on the flechettes. It should be noted that
applying the adhesive in strips, instead of over the entire
flechette array, leaves small spaces between the flechettes which
can easily be penetrated by the benzene for quick and easy access
to the adhesive.
After the adhesive is dissolved, the mold is set upright and the
manifold heads are removed from the mold. A plate 31 is secured to
the bottom of the mold to seal the bottom closed. A matrix material
is then poured into the mold, as shown in FIG. 8. The matrix
material, which can, for example, be microcrystalline wax, is
heated by heater 40, into a liquid form for application to the
flechettes in the mold. When the liquid wax cools, the flechettes
are held together by the solidified wax, and the pack 41 of
flechettes is then removed from the mold. Each pack 41 will be of
the shape shown in FIG. 9, in which four packs 41 are shown in
spaced relation for clarity. When the four segmental packs 41 are
in side to side contact (moved inwardly as far as possible from the
position shown in FIG. 9) they will form a cylinder 42 with an
opening therethrough.
An artillery shell 43 has a central core 44 and a cavity 45 of
annular cross section surrounding the core. Four flechette packs
are then installed in the shell to form a cylinder 42. The
flechette packs are readily frangible, and the flechettes will be
dispersed when the shell explodes.
Although the best mode contemplated for carrying out the present
invention has been herein shown and described, it will be apparent
that modification and variation may be made without departing from
what is regarded to be the subject matter of the invention.
* * * * *