Improvements in Safety Fuses for High Explosive Shells.
Year: 1897

page_text: COMPLETE SPECIFICATION.
Improvements in Safety Fuses for High Explosive Shells.
I, LOUIS GATHMANN, of 98 Delaware Place, Chicago, in the County of Cook,
State of Illinois, United States of America, Mechanical Engineer, do hereby declare
the nature of this invention and in what manner the same is to be performed, to
be particularly described and ascertained in and by the following statement:-
This invention relates to a novel method of constructing a safety fuse, for shells
carrying large masses of high explosives, whereby the danger of accidental and
premature explosion of said shell is prevented, and an instantaneous explosion is
ensured immediately upon the shell striking any resisting object such as armor plates
or earth-works. To attain this security from accidental and premature explosion I
provide a fuse wherein the detonating charge is normally located at such distance
from the priming charge that it will not detonate said charge even though the fuse
should itself explode. That is to say, the detonating charge or fuse consisting of
dry gun-cotton and a fulminating cap is preferably mounted in a thin shell or stock
normally supported so as to occupy a central position in a strongly constructed
detonating chamber, which thus locates the fuse at a considerable distance from the
priming and main body of explosives, which, as they require a sharp detonation in
immediate contact with them to cause their explosion, will not be affected by any
premature or accidental detonation of fuse.
This distance of detonating charge or fuse, from priming charge is gradually
decreased after the shell has been fired from the gun and its distance continues to
decrease until finally when the shell has made a flight of several hundred yards, the
detonating charge or fuse has decreased the distance between it and the priming
charge to nil, and rests in close contact with the same. The percussion cap of the
detonating charge or fuse will then explode the same in the usual manner upon
impact or retardation of the shell, and thereby cause the almost instantaneous
explosion of the priming and main charge of the explosives.
I obtain the before stated results as follows: First, I provide a shell loaded with
large masses of high explosives, said shell preferably having an open or partially open
hase, through which the gases of the expelling charge may pass to the interior of
the shell to equalize the internal and external pressures, thereby allowing the shell to
be constructed of minimum weight and with a maximum of space for the explosive
material. Second, I provide a strongly constructed chamber or chambers in which
a priming of high explosive material such as gun-cotton containing only a small
percentage of water is located. Third, I also provide a strongly constructed chamber.
or chambers having an area much larger than that of the fuse, wherein a detonating
cartridge or fuse is located, said chamber protecting the priming and main charges
of high explosives from premature explosion, even though the detonating cartridge
of the fuse should be accidentally or prematurely exploded.
It is a well known fact that some high explosives, notably wet gun-cotton, will not
explode by any ordinary concussion or blow, and that it is necessary to explode a
strongly charged detonating cap or cartridge in close proximity to such explosives to
ensure their explosion. This I accomplish by my mode of construction while the .
detonating cap or fuse is kept apart from the priming charge and main body of
explosive at least until the projectile has been discharged from the gun.

page_text: In the accompanying drawings,
Figure 1 is a longitudinal section of a shell or projectile, having a detonator with
its priming chamber and fuse at each end.
Figure 2 is an enlarged longitudinal section of priming and detonating cases,
showing a plunger and fuse in the position they occupy in the shell before the latter
has been fired from the gun.
Figure 3 is an enlarged longitudinal section showing the position of said plunger
and fuse in the shell after it has been fired from the gun, the fuse having passed into
the priming chamber and being in close contact with the plunger.
In the drawings, the projectile or shell is marked A, and the main explosive
charge B. The priming chamber case C is preferably secured either to the head or
base of the shell A, depending upon the location desired; or two detonating cases
may be used in each shell, one at each end to insure against misfire. The detonator
chamber case D is preferably secured to the primer chamber case C. In the
detonating chamber D is located a percussion fuse, which consists of a plunger held
in place in a stock g by a brittle screw or other suitable holding device; a detonating
charge of dry gun-cotton K held in one end of the plunger; and a fulminate cap m,
all contained and supported within a thin tube or container n. On the base of the
plunger is secured a soft metallic stud p which will absorb some of the severe shock
on the release of the holding device due to the firing of the gun.
In the forward part of the detonator case D, is secured a guide tube O, the
forward end of which is closed by a plunger R, normally held in place by the brittle
screw as shown in Figure 2. The plunger and also the plunger R are normally
held in place by brittle screws to guard against the fuse or detonating cartridge
coming into contact with the priming charge close enough to endanger same, should
an explosion of said fuse or detonating cartridge occur prematurely. S indicates the
priming charge preferably of gun cotton containing a smaller percentage of water
than the main charge B. W indicates an asbestos pad or washer.
When the shell is fired from the gun, the plungers f and R being held to the
shell only by the brittle screws will break their fastenings and will set back the
stud p on the plunger f, absorbing a portion of the shock, while the shoulders r on
the plunger R strike upon the end of guide-tube O and prevent it from moving back
too far.
Figure 3 shows the normal position of the fuse mechanism, after the shell has
been fired from the gun and reached a point say several hundred yards from the
muzzle of the same, and has decreased its speed from the highest imparted by
the gun.
The plungers R and being heavier than the mean density of the shell and
combined contents and not being subjected to the exterior aerial resistance of said
shell A, will in consequence attain forward movement relative to the shell, and after the
shell has made a flight of say several hundred yards, will reach the positions indicated
in Figure 3. By constructing a shell loaded with high explosives of three distinct
parts as herein shown and described, the shell is protected from any accidental or
premature explosion. These three parts are: First. The shell A, containing the large
mass of high explosive, preferably wet gun-cotton. Second. A priming chamber
case C, containing the more sensitive charge of gun cotton or other explosive, and,
Third. A detonating chamber case D, in which the most sensitive or initial explosive is
located, said chamber being large and strong enough to withstand the full pressure
exerted by an accidental or premature explosion of the detonating charge or fuse
which is held therein, without communicating any severe shock to the priming or
main charge of explosives.
The detonating chamber as shown is about thirty times as large as the fuse located
therein. The initial explosive force of dry gun-cotton is estimated as above 400,000
pounds to the square inch when closely confined, and such force decreases in
proportion to the increased area wherein it is exerted. My device is intended to so
reduce it, by providing increased area about it; that the walls of the strongly
constructed chamber will be ample to withstand the shock. The required area may

page_text: be easily computed, and thus by properly applying my invention, any premature
explosion of the fuse will result in no damage to the shell itself other than a
misfire. The fuse should preferably be located in the axis of the chamber so that
the force of an accidental explosion will be distributed equally upon its walls.
For example,
It is obvious that modifications of my invention may be made.
the detonating charge or fuse might be located in various positions within the
body of the shell. The shell may also be of various constructions, although I have
shown the preferred form.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:
1. In a high explosive. shell, a safety fuse consisting of a chamber with walls
of predetermined strength, with a fuse in said chamber, the cubical capacity of
said chamber bearing a certain relationship to the cubical capacity of the fuse,
whereby, when the said fuse is exploded in the said chamber, the force of the
explosion is reduced to less than a rupturing strain and the said explosion is
isolated.
2. The herein described improvements in fuses for high explosive shells consisting
of a chamber containing a priming charge of explosive material, a second chamber,
a fuse normally held within said second chamber and a normally closed passage
between said chambers through which the fuse may pass during the flight of the
shell, substantially as described.
3. The combination with an explosive shell of a detonator consisting of a chamber
containing a priming charge of explosive material, a second or fuse chamber,
located in line therewith, a guide tube connecting said chambers and a fuse
normally held in the second chamber in line with said tube, said fuse-chamber
being of a cubical capacity greatly in excess of that of the fuse contained therein,
substantially as described.
4. The combination with an explosive shell of a detonator consisting of a
priming chamber having a priming charge of explosive material secured therein
with a central passage or opening through the body of said charge, a detonating
or fuse chamber, a fuse supported therein, a guide tube connecting said chambers
and a plunger normally supported within and closing said tube, substantially as
described.
5. The berein described improvement in fuses for high explosive shells consisting of
a casing providing in one end thereof a priming chamber, a second casing providing
a detonating chamber, a guide tube connecting said chambers, a fuse normally held
within said detonating chamber in line with said tube and a plunger normally
sustained within and closing said tube, said plunger and said fuse being adapted to
be dislodged by momentum during the flight of the shell, substantially as described.
6. In a safety fuse for high-explosive shells the combination with a detonator
casing having a priming chamber and a fuse chamber, a guide tube connecting said
chambers and a fuse support located within the fuse chamber and adapted to support
the fuse in line with the guide tube and said support being open to the fuse chamber
space whereby the shock of a premature explosion may be dissipated within said
chamber, substantially as described.
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.