June 23, 1964 R. F.

HATFIELD 3,138,054
PROCESS OF MAKING LINEAR SHAPED CHARGE EXPLOSIVE DEVICES
Filed Nov. 7, 1960 3. Sheets-Sheet

--- - - - - - --- --

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S.

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(e) 429
Richord F. Hotfield
INVENTOR

59 S2 Fig. By 4-4- 6 2a-2. ATTORNEY

June 23, 1964 R. F. HATFIELD 3,138,054
PROCESS OF MAKING LINEAR SHAPED CHARGE EXPLOSIVE DEVICES
Filed Nov. 7, 1960 3. Sheets-Sheet 2

22272ZZZZZZZZZZZ2

INVENTOR
Richard F. Hotfield

BY-2%- 6 2and 2. ATTORNEY

June 23, 1964 R. F. HATFIELD 3,138,054
PROCESS OF MAKING LINEAR SHAPED CHARGE EXPLOSIVE DEVICES
Filed Nov. 7, 1960 3. Sheets-Sheet 3

39

INVENTOR
Richord F. Hotfield

BY 24-76. 6, 22442.
ATTORNEY
United States Patent Office 3,38,654
Patiented June 23, 1964
2
process adapted for manufacturing tubular, linear shaped
3138054 charge devices having various diameters.
PROCESS OF MAKING LiSEAR SHAPED CHARGE A further object of this invention is to provide a proc
EXPLOSIVE DEWCES ess for manufacturing tubular, linear shaped charge ex
Richard F. Hatfield, Stanford, Calif., assignor to get plosive devices which contain a uniformly distributed,
Research Center, Inc., Arlington, Tex., a corporatics highly compressed, particulate explosive material through
of Texas
Filed Nov. 7, 1960, Ser. No. 67,317 out the effective length of the shaped charge device.
3 (Claims. (C. 86-) Still another object of this invention is to provide a
process for making a semiflexible, tubular, linear shaped
This invention relates to a process of making tubular, 0. charge device having a unitary shaped charge casing and
linear shaped charge explosive devices. liner which contains a uniformly distributed, highly
Some forms of tubular, linear shaped charge explo compressed, particulate explosive material throughout the
sive devices utilizing preformed metal casings have been effective length of the shaped charge device.
made heretofore by filling the casing with a molten explo Briefly stated, the process of the invention includes
sive material and allowing the explosive to solidify in 15 providing a length of elongated, generally tubular casing
place. Even when using a flexible tubular casing, the having a longitudinally extending, deformable wall por
extent to which such linear shaped charge devices can tion being capable of taking a permanent set; forcing
be bent to conform to the shape of an object to be cut is inwardly the longitudinally extending deformable wall
quite limited due to the brittle nature of most cast explo portion of the casing to produce a longitudinal groove
sive compositions. Breaks produced in the rigid cast 20 in the casing thereby reducing the internal volume of
explosive material by bending the casings are likely to the casing; thereafter filling the grooved casing with par
cause "cut-off” of the detonation wave as it proceeds ticulate high explosive material; and forcing inwardly
down the length of explosive in the casing with the re the longitudinally extending deformable wall portion of
sult that only a portion of the length of the charge device the explosive filled casing along the longitudinal groove
is detonated. 25 to produce a longitudinal groove of increased depth.
Thus, the use of particulate explosive materials in fill Thus there is formed a re-entrant shaped charge cavity
ing linear, tubular shaped charge devices is desirable to linear from the deformable portion of the casing. More
achieve a flexible shaped charge device that can be bent over, the particulate high explosive material is compressed
to cut irregular shaped objects and yet insure the con between the inner walls of the casing and is shaped to
tinuity of a detonation wave throughout the length of the 30 conform to the inner walls to produce a linear shaped
shaped charge device. In fact, some of the high explo charge having a lower explosive weight per unit length
sive materials preferred for certain operations, such as and a deeper longitudinal groove compared to a linear
Cyclonite and HMX, have such high melting points that shaped charge produced as described in the foregoing
they cannot be conveniently cast but are best used in the 35
steps with the exception that the casing is not pregrooved
particulate form. It is well known in the art that increas to reduce the internal volume thereof before being filled
ing the apparent density of the explosive material in a with particulate explosive material.
shaped charge device will produce an increase in the pene Further in accordance with the invention, the steps of
trating ability of the device. Achieving the desired de grooving the casing or the steps of deepening the pre
gree of compression of a particulate explosive material in 40 formed groove may be carried out in a plurality of suc
situ in a preformed, elongated, tubular shaped charge cessive operations.
device has heretofore been a difficult and time consuming One form of apparatus for performing the process of
operation. Small increments of explosive material are the invention includes a supporting frame that supports a
usually poured into a pregrooved tubular casing which is first shaft on which is mounted a backing wheel for rota
closed on one end and then compacted by a rod intro tion about its axis. The backing wheel provides an an
duced through the open end of the tube. A uniform dis nular groove continuous about its periphery. A groov
tribution of high density explosive material throughout ing wheel is supported by a second shaft on the frame for
the length of the casing is very difficult to obtain when rotation about the axis of the grooving wheel. The rim
using such packing methods. of the grooving wheel is convex in axial cross-section.
Therefore, it is an object of this invention to provide a The axes of the wheels are disposed substantially parallel
process for manufacturing tubular, linear shaped charge 50 to each other, and the groove of the backing wheel and
explosive devices which have a uniform distribution of the rim of the grooving wheel are disposed substantially
highly compressed, particulate explosive material through in a plane. Means for rotating at least one of the wheels
out the effective length of the shaped charge devices. is provided.
Another object of this invention is to provide a process The product produced by the process of the invention
for manufacturing tubular, linear shaped charge explo includes a semi-flexible, tubular, linear shaped charge unit
sive devices wherein a longitudinal groove is formed in which has an elongated, generally tubular casing having a
the wall of a permanently deformable, generally tubular longitudinal, re-entrant portion in the wall thereof. A
casing and the explosive material in the casing is com body of compressed, particulate high-explosive material
pacted to the desired density simultaneously with the is contained within the casing. The explosive material
grooving operation. 60 conforms in shape to the inner walls of the casing, having
A further object of this invention is to provide a proc been compressed and conformed to the shape therein by
ess for manufacturing tubular, linear shaped charge ex inward deformation of that portion of the casing which
plosive devices which utilizes an economical, readily provides the longitudinal re-entrant wall portion.
available component for forming a unitary shaped charge The process of the invention may be performed using
casing and liner. 65 various instrumentalities or even by hand, as will be ex
A still further object of this invention is to provide a plained more fully hereinafter. One such instrumentality,
process for forming a longitudinal groove in a perma which itself forms a part of the present invention, is the
nently deformable, generally tubular casing of a shaped machine shown in the accompanying drawings.
In the drawings:
charge explosive device and compacting the explosive 70 FIG. 1 is an elevational view of a typical machine for
material therein at the same time. forming, in accordance with the invention, linear shaped
An additional object of this invention is to provide a charge explosive devices;
 3,188,054
3. 4.
FIG. 2 is a right side view of the machine of FIG. 1; The spring ends are seated in shallow opposed recesses
FIG. 3 is a sectional view taken along the line 3-3 of in the edge of the support block and the bottom wall of
FIG. 1; opening 24 to retain the springs in position. A pair of
FIG. 4 is an enlarged cross-sectional view taken on line retainer plates 40, 40 is attached to the outside of each
4-4 of FIG. 3 of the casing before grooving and the 5 of the side walls by means of screws 41. These retainer
explosive therein before compacting; plates are positioned adjacent to the openings 24 in the
FIG. 5 is an enlarged cross-sectional view taken on the side walls and extend over the openings 24 a short dis
line 5-5 of FIG. 3, of the casing after grooving and the tance on the vertical sides thereof. The overlap provided
explosive therein after compacting; by the retainer plates prevents the supporting blocks 34
FIG. 6 is a view in section taken along the line 6-6 from working out of the openings 24.
of FIG. 1, showing in detail a means for adjusting the A grooving wheel 42 is axially mounted on shaft 36
spacing between the grooving and backing wheels; centrally between the side walls 21 of the frame. An
FIG. 7 is an elevational view, partially in vertical medial axial cylindrical opening is provided through the groov
section, of a linear shaped charge exposive device made ing wheel to receive shaft 36. In one side of the groov
by the process of the present invention; 5 ing wheel an axial cylindrical counterbore 43 is provided
FIG. 8 is a side view of the linear shaped explosive to receive a roller bearing assembly 44. A washer 45 on.
charge device of FIG. 7; the shaft 36 fits into the counterbore to hold the bear
FIG. 9 is an elevational view, partially in section, of a ing in place. Sleeves 46, 46 and adjacent spacer washers
linear shaped charge exposive device mounted on an object 47, 47 are received on the shaft 36 on each side of the
to be severed, showing one system for detonating the 20 grooving wheel. The axial dimensions of the sleeves and
charge; washers are such that the rim of the grooving wheel is
FIG. 10 is a left side view of the organization of FIG. positioned centrally over the groove 31 in the backing
9; and wheel 30. The grooving wheel illustrated has a rim por
FIG. 11 is a cross-sectional view of the centering tube tion that is generally V-shaped in cross-section. The
and guide screw of a typical grooving machine. 25 peripheral surface at the terminus of the V is rounded
Referring now primarily to FIGS. 1, 2 and 3 of the slightly to prevent cutting the shaped charge tubular cas
drawings wherein a typical embodiment of a machine ing when forming the shaped charge device. Other rim
for manufacturing generally tubular, linear shape ex shapes may be utilized for the grooving wheel, such as
plosive charge devices is shown, the rectangular shaped parabolic or hemispherical, to provide the contour
frame 20 has a pair of parallel, spaced apart side walls 30 desired for the groove in the linear shaped charge device.
2, 21 rigidly joined at their ends to a pair of spaced A tube straightener or centering device is mounted on one
apart, parallel end walls 22, 22 by welding or other suit edge of the support frame as can best be seen in FIGS.
able means. A base plate 23 is rigidly attached, by weld 1, 2 and 3. The centering or straightener tube 48 is a thick
ing or other means, to the outside of the lower end wall. walled, cylindrical section of metal providing a cylindrical
The base plate extends a substantial distance to one side 35 opening 49 therethrough. It is adapted to snugly and slid
of the frame to provide a means for attaching the ma ably receive the tubing section or casing 50 for a tubular,
chine to a work table. The side walls provide a pair of linear shaped charge device and guide the casing into the
generally rectangular, opposed openings 24 in the upper groove 31 in the backing wheel adjacent to the edge of
one-half of the walls. In the lower one-half of the side the grooving wheel. A guide screw 74 is threaded through
walls, a pair of generally cylindrical, opposed openings 40 the wall of the centering tube 48 adjacent the forward
25 are provided. - end. A forward tube holder block 51, providing an open
Roller bearing assemblies 26 are press fitted into each ing therethrough, receives the tube straightener and po
of the openings 25 in the frame side walls. These bear sitions it in line with the groove in the backing wheel.
ing assemblies provide axial openings therethrough in The block has trunnions 52 on each end received in open
which is received a cylindrical shaft 27. The shaft is 45 ings provided in two bearing blocks 53, each of which is
mounted flush with the exterior surface of the left side wall attached by screws 69 to the side walls 21 of the frame.
and projects a short distance out from the exterior Surface The bearing blocks have slots. 70 in their bases to receive
of the right side wall. A crank 28 is rigidiy attached to the mounting screws to permit vertical positioning of
the projecting end of the shaft 27 by means of a set the forward end of the tube straightener. A set screw 54
screw 29. A backing or driving wheel 30 is axially in the forward holder block locks the tube straightener
mounted centrally on that portion of shaft 27 extend in the selected position. A rearward tube holder block
ing between the side walls 21. The driving wheel pro 55a, like the forward tube holder block, supports the rear
vides an annular groove 31 continuous about the pe ward end of the straightener tube 48. A pair of brackets
riphery and has integrally formed collars 32, 32 extend 55, 55 supports the rearward tube holder block. Slots 71,
ing axially equidistantly from each side thereof. The 78 are provided in the feet of the brackets for attachment
driving wheel is attached to the shaft 27, to rotate there to the edge of the side walls of the frame by screws 72, 72
with, by set screws 33 received in threaded transverse to permit vertical positioning of the rearward end of the
openings in the collars 32. ... . tube straightener. The edges of the frame side walls 21,
Referring now to FIGS. 2 and 6, the generally rec 21 may be tapped at a number of places, as shown in FIG.
tangular opening 24 provided in each of the upper one 60 1, to provide a variety of positions for mounting the
half of the side walls 21 contains a rectangular support bearing blocks 53 and-the-brackets 55. -
block 34. The support blocks are constructed to provide A gage support bracket 56 is attached by screws 73
a snug, slidable fit with the vertical walls of the open to the top end wall 22 of the frame. . A dial-reading
ings 24 to permit vertical movement of the blocks within micrometer gage 57 is attached to the support bracket.
the openings 24. Each of the support blocks provides a 65 The gage is actuated by the upper end of an extension rod
central opening 35 therethrough. A cylindrical shaft 36 58, which is slidably mounted in a vertical opening in the
extends between the side walls and the ends of the shaft top end wall member 22. The lower end of the extension
are received in the openings 35 of the support blocks. rod rests on the rim of the grooving wheel 42. The gage
The support blocks are vertically positioned within the and extension rod provide a means for determining the
openings 24 by adjusting screws 37, 37. Two threaded 70 amount of change in vertical spacing between the grooving
vertical screw holes 38 are provided in each of the side wheel and the backing wheel, as will be more fully ex
walls to receive the adjusting screws 37. A pair of plained hereinafter.
springs 39 extend between the lower edge of the support A particularly advantageous feature of the foregoing
blocks and the bottom wall of the openings 24 to urge the apparatus is adaptability of the apparatus to the manu
blocks into engagement with the adjusting screws 37. 75 facture of linear shaped charge units having different diam
 3,138,054
6
eters. A number of backing wheels 30 may be provided, through the machine. If the casing is allowed to twist or
each having a peripheral groove 3 of a different radius turn, it will cause the groove 60 to have a twisted path
corresponding to the radii of commonly available sizes of around the casing. The casing 50 is then run through the
tubing. Separate backing wheels each having a peripheral grooving machine again to increase the depth of the
groove radius to accommodate tubing in the sizes 4 in., groove 60. This process is repeated until the final depth
% in, /2 in., and 34 in. O.D. are normally used. Refer desired for the groove 60 is achieved.
ring to FIG. 1, it can be seen that the backing wheel 30 The grooving machine is readily adjusted to produce
can be readily changed by loosening set screws 33, sliding shaped charge units in a straight or curved form. Curved
the shaft 27 out of the bearing assemblies 26, removing the shaped charge units may be made with the groove 60
grooving wheel and replacing it with one of a different O facing toward or away from the center of curvature.
groove radius. The same grooving wheel 42 is used for A curved shaped charge unit having the groove 60 facing
manufacturing linear shaped charge units of the several toward the center of curvature is produced by position
diameters. ing the brackets 53 and 55 so that the axis of the center
The process for manufacturing linear shaped explosive ing tube 48 intercepts the groove 31 in the backing wheel
charge units or devices utilizing the foregoing apparatus 5 30 from above the horizontal. A curved shaped charge
is as follows: unit having the groove 60 facing away from the center
A Section of tubing of Suitable length is cut from a of curvature is produced by positioning the brackets
roll of tubing of the selected diameter and straightened to 53 and 55 so that the axis of the centering tube 48 inter
provide the casing 50 for the linear shaped charge unit. cepts the groove 35 in the backing wheel 30 from below
Refrigeration grade, soft-drawn copper tubing is preferred 20 the horizontal. Increasing the angle between the axis of
for the casing, but other tubing capable of taking a per the centering tube 48 and a horizontal line between the
manent set, such as aluminum or lead, may be used. One grooving and backing wheels will shorten the radius of
Open end of the section of tubing is closed by a strip of curvature of the shaped charge unit and vice versa.
tape, or by inserting therein a cork or rubber stopper A modification of the hereinbefore described process
(not shown). The tubing section is then supported in the for manufacturing linear shaped charge devices has been
Vertical position with its open end uppermost. A par developed which permits varying the weight of explosive
ticulate detonating explosive material 59 (as shown in material contained in a unit length of tubing of given
FIG. 4) is then poured into the open end of the tubing sec diameter. Thus, the cutting power of linear shaped .
tion to substantially fill the section. It is advantageous, charge units made from the same diameter tubing may
particularly when filling smaller diameter tubing sections, be widely varied to fit the specific job at hand. The
to add the explosive slowly accompanied by gentle tap variation in explosive weight per unit length of casing
ping on the tubing wall to prevent bridging of the ex is controlled primarily by pregrooving the empty tubing
plosive and consequent formation of voids or spaces. The section before it is filled with explosive material. A
upper end of the tubing section is then sealed in the same secondary control of the explosive density may be effected
manner as the lower end. Referring now to FIGS. 3, 4 by tamping the explosive into the pregrooved tubing
and 5, a backing wheel 30, providing the proper sized pe section with a tamping rod. The following table gives
ripheral groove to accommodate the size of tubing used Some specific data concerning the explosive loadings per
for the casing 50, is mounted in the grooving assembly as unit length when using the process utilizing pregrooving
hereinbefore described. The screws 37 are screwed out of the empty tubing section and tamping the explosive.
to permit the grooving wheel 42 to be raised by springs 39 40 TABLE
a Sufficient distance to allow the casing 50 to pass freely
underneath the grooving wheel edge. One end of the ex Explosive Load (Ginn.) Per Unit Length (Foot) When
plosive filled tubing section 50 is then inserted through the Using 0.500' O.D. Soft Copper Tubing
opening 49 in the centering tube 48 to extend into the
groove 3 opposite the rim of the grooving wheel 42. Pregroove Depth in Tubing (in.)
Weight of Ex-Weight of Ex
plosive With- plosive With
The screws 37 are then screwed in until the edge of out Tamping Tamping
the grooving wheel 42 contacts the wall of the casing 50. (gmift.) (gmift.)
The micrometer gage 57 scale is then rotated to set 0
opposite the pointer. The casing 50 is then pulled back 0-00----------------------------------
0.10
28.38
25.20
29.2
28.65
out of contact with the grooving wheel 42 and the backing 50 0.150- 22.40 26.05
wheel 30. 0.200- 20.00 23.42
0.250---------------------------------- 17.26 20, 31.
The most satisfactory method of forming the groove
69 in the shaped charge unit casing is to pass the casing The pregrooving of the empty tubing sections is han
through the grooving machine a number of times, increas
ing the groove depth on each pass. Forming the groove dled in the same manner as the grooving of a tubing
to its total depth in one pass through the grooving ma section containing explosive. The total pregroove depth
chine may cause the casing 50 to split longitudinally at is achieved by making successive passes of the tubing sec
the apex of the groove. The screws 37 are screwed in until tion through the grooving machine. Between each pass
the micrometer indicates that the grooving wheel 42 has of the tubing through the machine, the grooving wheel is
moved toward the backing wheel 30 a fractional part of lowered slightly to increase the depth of the groove in
60 the casing. The successive passes are repeated until the
the distance desired for the total depth of the groove 60 desired pregroove depth in the tubing section is reached.
in the casing 50, for example, one-fourth the distance When making linear charges using 0.500 in. O.D. copper
desired for the total depth. The explosive filled casing tubing, it has been found that an increase in groove
is then pushed into the groove 3 of the backing wheel depth of 0.050 in. in the tubing section per pass is satis
and the crank 28 is rotated to draw the casing between the 65 factory. The grooving increment is decreased when using
wheels where the edge of the grooving wheel 42 forms a Smaller diameter tubing for the casing, and increased
longitudinal groove in the casing. When the casing has when using larger diameter tubing. After pregrooving,
passed through the machine, the screws 37 are screwed the tubing section is filled with particulate explosive
in again until the micrometer indicates that the grooving material. The explosive may be tamped as the tubing
wheel is lowered another incremental distance. The cas 70 Section is filled to increase the weight of explosive if de
ing 50 is inserted in the centering tube 48 and the guide sired. The explosive filled tubing section is then passed
screw 74 is screwed in until it projects into cylindrical through the grooving machine the additional number of
opening 49 to lightly contact the edges of the grooved times required to achieve the final depth desired for the
casing 50, as may be seen in F.G. 11. The guide screw groove and, also, to further compact the explosive within
74 prevents the casing from twisting or turning as it passes 75 the tubing section.
 3,188,054
7 3.
The groove 60 in the casing 50 of the linear shaped ing 50 to retain the charge 6 in position with the groove
charge unit should not be made so deep that substantially 60 facing the target 67.
all the explosive material 59 is forced from between the While the linear shaped charge devices shown are longi
apex of the grooved portion of the sidewall of the casing tudinally straight, it is to be understood that curvilinear
and the opposite side wall. Charges grooved too deeply forms of the charge devices are anticipated. As herein
do not form a properly shaped jet and, consequently, before stated, one of the principal features of the linear
have very low penetrating energy. shaped charge devices produced by the process of the pres
As stated hereinbefore, the process of the present in ent invention is their adaptability to cut curved or irregu
Vention for manufacturing linear shaped charge devices lar shaped objects. When a soft tubing is used for the
may be carried out utilizing a number of different in O charge casing, the shaped charge unit can easily be bent
Strumentalities. For example, a machine press may be by hand or by using an ordinary tubing bender to the
used which has a bed fixedly supporting the explosive shape of most irregular shaped objects that it is desired
filled, tubular casing and a powered W-shaped die extend to cut.
ing the length of the casing adapted to be moved into It is to be understood that the apparatus, the process
engagement with the supported casing to press a re 5 and the tubular, linear shaped charge explosive devices
entrant cavity in the casing. Another suitable machine is described herein are subject to wide modification without
one wherein the explosive filled, tubular casing is held departing from the scope and spirit of this invention. Ac
fixed to a rigid support structure and a lateral force is cordingly, the specific embodiments herein described and
applied to the casing by a grooving tool which is moved depicted are to be considered as merely illustrative and
the length of the casing to form the re-entrant cavity in 20 not as restricting the scope of the following claims.
the casing. The process is also capable of being carried I claim:
out by hand using simple hand tools, such as a hammer 1. A process for producing a linear shaped explosive
and a properly shaped punch, to produce the re-entrant charge unit which comprises: providing a length of elon
cavity in the casing and to compress the explosive therein gated, generally tubular casing having a longitudinally ex
simultaneously. 25 tending, deformable wall portion being capable of taking
For the purposes used herein, “tubular casing is de a permanent set; forcing inwardly said longitudinally ex
fined as including not only circular tubular casing, but tending deformable wall portion of said casing to produce
those of semi-circular, oval, elliptical, polygonal and a longitudinal groove in said casing thereby reducing the
other similar shapes. Also, the term includes tubular internal volume of said casing; thereafter filling said
casing of the shapes enumerated having a longitudinal 30 grooved casing with particulate high explosive material;
groove formed in a wall portion thereof prior to filling and forcing inwardly the longitudinally extending, de
the casing with explosive material and further deepening formable wall portion of said explosive filled casing along
the groove to compact the explosive material. said longitudinal groove to produce a longitudinal groove
Particulate explosive materials most suitable for use of increased depth, thereby forming a re-entrant shaped
in preparing the linear shaped charge devices are de charge cavity liner from said deformable portion of said
Sensitized Cyclonite or RDX (cyclotrimethylenetrinitra casing, compressing said particulate high explosive mate
mine) and desensitized HMX (cyclotetramethylenetri rial between the inner walls of said casing and shaping
nitramine). The term "particulate explosive material said high explosive material to conform to said inner
includes explosive material in a crystalline, granular or Walls, to produce a linear shaped charge having a lower
other discrete small particulate state as distinguished from 40 explosive Weight per unit length and a deeper longitudinal
fused or cast explosive materials. - -- groove compared to a linear shaped charge produced as
A description of an exemplary setup for cutting an described in the foregoing steps with the exception that
object explosively using a tubular, linear shaped charge the casing is not pregrooved to reduce the internal volume
device made according to the present invention follows. thereof before being filled with particulate explosive
A finished linear shaped charge unit 61, from which 45 material. -
the Sealed ends have been removed, is shown in FIGS. 7 2. A process for producing a linear shaped explosive
and 8. The corks or other sealing means (not shown) charge unit as set forth in claim 1 wherein the step of
used to seal the open ends of the casing 50 are normally. forcing inwardly the longitudinally extending, deformable
left in place until the linear shaped charge is ready for wall portion of said explosive filled casing along said longi
use. If cork or rubber stoppers are used to seal the cas tudinal groove to produce a longitudinal groove of in
ing ends, they are tightly held by the groove 60 and creased depth is carried out in a plurality of successive
cannot be easily removed. To prepare a linear shaped operations whereby the -depth of the groove is increased
charge for detonation, the casing 50 is notched, using by each said successive operation.
a file or other means, immediately to the rear of the cork 3. A process for producing a linear shaped explosive
and the end of the charge is broken off. The severed charge unit as set forth in claim 1 wherein the step of
end of the charge provides a fresh area of explosive mate forcing inwardly said longitudinally extending, deformable
rial 59 flush with the edge of the casing 50, which is Wall portion of said casing to produce a longitudinal
desirable for good contact with the detonating means. groove in said casing, and the step of forcing inwardly the
Referring now to FIGS. 9 and 10, an electric blasting longitudinally extending, deformable wall portion of said
cap 62 is held endwise in direct contact with the explosive 60 explosive filled casing along said longitudinal groove to
material on one end of the linear shaped charge by means produce a longitudinal groove of increased depth, are both
of strips of adhesive tape 63. Other means may be used carried out in a plurality. of successive operations where
to attach the blasting cap to the end of the shaped charge, by the depth of the groove is increased by each said suc
Such as a metal clip, adhesives or cements. The linear cessive operation,
shaped charges can be adapted for under water use by 65
Sealing each end and attaching a detonator with any suit
able Waterproof adhesive. A pair of electric lead wires
References Cited in the file of this patent
68 are attached to the blasting cap and extend to a safe, UNITED STATES PATENTS
remote location where one leg wire is connected through 2,589,541 Croson ---------------- Mar. 18, 1952
switch 64 to one side of a battery 65 and the other leg wire O 2,638,323 Bannon ---------------- May 12, 1953
is directly connected to the battery. The linear shaped 2,826,235 Gudmestad ------------- Mar. 11, 1958
charge is supported by brackets 66 to provide the proper 2,851,918 MacLeod -------------- Sept. 16, 1958
standoff distance from the target 67. These brackets are 2,966,822 Kistiakowsky et al. -------- Jan. 3, 1961
conveniently made of strips of metal, such as brass or FOREIGN PATENTS
aluminum and are adapted to clip over the charge cas 75 733,592 - Great Britain ----------- July 13, 1955