Improvements in Safety Fuses for High Explosive Shells.
Year: 1898

page_text: Date of Application, 20th Jan., 1898-Accepted, 18th June, 1898
COMPLETE SPECIFICATION.
Improvements in Safety Fuses for High Explosive Shells.
We, LOUIS GATIMANN, and EMIL GATIMANN, both of No. 46, Lincoln Avenue,
in the City of Chicago, County of Cook and State of Illinois, United States of
America, Engineers, 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 safety fuses for high explosive shells, and particularly
for that class of shells in which wet gun cotton is used as the explosive or burst-
ing charge.
The object of the invention is to absolutely insure the main charge of explosive
material against premature explosion during the handling or transportation of
the shell, or while it is in, or being fired from the gun.
To attain these objects we provide a projectile to contain a main explosive
charge, such as wet gun cotton, and having a fuse affixed in the base of the shell,
said fuse containing the detonating charge consisting of a suitable detonating
compound or fulminate and a mass of dry gun cotton.
as to render
The body of the fuse is divided transversely into two chambers, one of which
(hereinafter called the safety chamber) is removed from the main explosive charge
and in which the dry gun cotton, and if desired, the fulminate compound is
placed; and this detonating charge is not only separated from the
main charge at such distance
the setting off of the
main charge prematurely extremely unlikely, but to further insure against
such premature explosion the fuse chamber is transversely divided by strong
plates normally in position to cut off all communication between the mass of dry
gun cotton and the main charge of wet gun cotton, said plates being held in
place to effect this separation either mechanically or by pressure should a pre-
mature explosion of the dry gun cotton occur, while they are moved laterally to
permit the passage of the fuse into the other or detonating chamber by centri-
fugal force caused by the whirling of the projectile when discharged from the
gun.
By means of our invention, therefore, the dry gun cotton is completely separated
and isolated from the main explosive charge whereby premature explosion of the
main charge is impossible, and the construction is also such that when the pro-
jectile meets with sufficient resistance such as impact upon the object fired at,
the detonating charge will then be in proximity to the main explosive charge so
that the explosion of the latter will be insured."
Our invention may be embodied in various forms of construction, some of
which are represented in the accompanying drawings which will now be described.
In the accompanying drawings,
Figure 1 is a longitudinal section through the base of a shell and through our
improved fuse on line W W Fig. 2.
Figure 2 is a cross section on line W W of Figure 1.
Figure 3 is a cross section on line X X of Figure 2.
Tio 4 is a longitudinal section of the rear portion of the tube or barrel of

page_text: the gun showing the front of the powder chamber and containing a half sectional
plan of the base of the shell and our improved fuse.
Figure 5 is a longitudinal sectional view to a larger scale of the rear end of a
shell having a closed base and showing our improved fuse mechanism in position
therein.
Figures 6, 7 and 8 show in sectional plan, transverse, and longitudinal sections
respectively, a modified construction of safety fuse, embodying however the
general principles of our invention.
In the drawings let 1 represent the body of the shell, and 2 the base plug
thereof, said parts having a threaded connection with each other. To the base
plug is secured a cup like stock 3 constituting a safety chamber to contain the
detonating charge of dry gun cotton. A base ring 21 secured within the base
of the shell carries a second cup like portion 4 which constitutes the detonating
chamber and may contain the detonating compound or fulminate, as hereinafter
described.
We designate the space within the part as a safety chamber and locate therein
a stock 5 held in place by the brittle screws 12 and containing
a mass of dry
gun cotton 15, held in place by the threaded plate 13. Within the cup like por-
tion 4 constituting what we have denominated the detonating chamber may be
affixed, as shown in all of the views excepting Figure 5, the detonator stock or
cartridge 6 containing the detonating compound 18, protected by the cushion 17,
and adjacent thereto a detonating cap 21. In the construction shown in Figures 4
and 6 the retaining plate 13 has a conical flange 14 thus affording a cavity which
the detonating cartridge may enter.
The base ring 21 is secured to the base 2 by means of intermediate pieces 24
and the pins 23. The base pieces 24 are segmental in form.
7, 7 represent semi-circular discs or plates, each mounted upon a pivot pin 22,
the ends of which rest within apertures in the base 2 and the base ring 2¹. These
semi-circular discs have an interlocking joint preferably formed by tongues 16
on one member, entering grooves in the other member, and when closed together,
their outer edges have an abutment between the base 2 and the base ring 2,
while their meeting edges interlock thus forming a close partition between the
safety chamber and the detonating chamber. These discs are held closed upon
each other by the pins 8, which pass through apertures in the intermediate base
pieces 24. As shown in Figures 1 to 5 inclusive, these pins have shouldered
heads resting within similar apertures in the shell 1, and held therein by thin
strips of solder or frangible metal 9.
The outer surface of the head being flush with the outer surface of the shell,
and the inner ends of the pins contacting with the edges of the discs 7, as shown
in Figure 4, these pins bear upon the interior wall of the gun, which as shown
is rifled, the head being sufficiently wide to bear upon the lands of the rifling.
By this abutment or contact of the heads of the pins with the interior wall of the
gun barrel, the pins are absolutely prevented from outward movement while the
shell is in the gun and thereby the discs are held tightly closed until the shell is
fired from the gun. The frangible strips 9 will retain the pins in place during
the handling or transportation of the shell, and thus at all times when premature
explosion would likely prove injurious, the mass of wet gun cotton is protected
from explosion by the complete isolation of the detonating charge therefrom.
The heads of the pins 9 are packed by packing rings 11 to prevent ingress of the
gases of the expelling charge to the dry gun cotton.
As shown in Figure 5 the cartridge or stock 171 containing the fulminate 18
and the cap 21 are placed within a stock 6¹ in the safety chamber, and held
therein by the break pins 121. The outer end of the stock is sealed by the
block 6. Should the priming charge be detonated by concussion, or from any
cause while the shell is being handled or while it is in the gun the mass of dry
gun cotton would not of itself generate sufficient force to explode the main
charge of wet gun cotton in the body of the shell because of the protection

page_text: afforded by the discs or partitions 7. Such a premature explosion, while it would
probably destroy the walls of the safety chamber, could not penetrate the plates 7
and reach the interior of the body of the shell. In this construction we employ
a packing or cushion 10 to prevent ordinary shocks from causing violent con-
cussion such as might set off the dry gun cotton.
As shown in Figures 6, 7 and 8 the discs 7 are held in place by pins 8 which
are capable of outward movement in the apertures 27 of the intermediate base
pieces 24 and which pins are held in contact with the edges of the discs by means
of the counter pins 81, said last mentioned pins being arranged at right-angles
to the pins 8 and the points thereof protruding into the passage 27 and contacting
with the outer bevelled ends of the said pins 8. A body of rocket powder 811 is
confined against the heads of these pins.81 by means of the solder strips 9 and the
screw plugs 91, the latter being centrally apertured and open to the flame gener-
ated by the explosion of the powder constituting the expelling charge. Such
explosion would ignite the rocket powder and thus permit the counter pins 81
to move backwardly during the flight of the shell and thus allow the pins 8 to be
thrown outwardly by centrifugal force permitting the discs 7 to separate and the
detonating charge to pass bodily into the forward chamber.
Describing now the operation of our safety fuse as shown in Figures 1, 2 and 3,
the shell being enclosed within the gun, the heads of the pins 8 are in contact
with the wall of the gun barrel, thus holding the discs 7 closed and isolating the
charge of dry gun cotton from the mass of wet gun cotton. When the shell
has cleared the gun it has attained a rapid whirling motion due to the rifling of
the barrel, and by reason of such revolving motion the frangible strips 9 will be
ruptured, the pins 8 will be thrown out and the discs 7 will separate, thus placing the
two ends of the fuse chamber in open communication with each other. The first
shock of the explosion of the expelling charge will operate to cause the container 5
to set back thus breaking the pins 12, and during the flight of the shell said
container will move forward to the position shown by dotted lines in Figure 1
thus bringing the plunger 20 into close proximity to the cap 21. When the
shell strikes a solid object the impact will cause the plunger to explode the cap
and also the mass of detonating compound 18 and thereby the mass of dry
gun cotton 15. We have found by experience that while the detonation of the dry
gun cotton will readily rupture a thick walled fuse, still the detonation of the wet gun
cotton is made very uncertain when such thick walled fuse is employed. There-
fore, we reduce the walls of the detonating chamber 4 as shown at 19, so as to
insure perfect detonating of the wet gun cotton when the detonation of the
primary charge occurs. An equivalent provision is shown in Figures 4 and 6
where the walls of the detonating chamber 4 are provided with openings normally
covered by an annular seal ring 25 held by the break pin 26. In the last described
construction when the shell is fired the ring 25 will set back thus breaking pins 26
and the ring during the flight of the shell will move forward uncovering the
apertures 19 and thus placing the interior of the detonating chamber in open
communication with the main shell chamber containing the wet gun cotton.
For similar reasons the walls of the cartridge stock 6 and of the container 5 are
reduced in thickness as shown at 191 1911 thus insuring the rupture of the stock
and container by the explosion of the fulminate cap, and of, the mass of dry gun
cotton, respectively.
In Figure 4 the fuse chamber is mounted upon the base plug 2 as before
described, but said base is capable of movement into the body of the shell 1,
thereby insuring an increase of pressure upon the contents of the shell due to
the pressure of the expelling charge and equivalent to the external pressure upon
the walls of the shell from the gases of the same expelling charge. This movable
base is provided by extending the base ring 21 so as to telescope with the shell 1
and providing the same with an offset or shoulder in its outer surface which will
be engaged by the flange of the retaining ring 1', suitable packing 211 being
interposed between said shoulders. Instead of using the pins 23 as shown in the

page_text: other figures of the drawing, the base 2 and the base ring 21 are coupled together
by the threaded coupling 1. When the shell is fired the pressure of the gases
of the expelling charge will cause the entire base of the shell to move into the
body thereof thus compressing the contents of the shell and transmitting to the
interior an increased pressure and assuring an equilibrium of pressure internally
and externally.
In the construction shown in Figures 6, 7 and 8 we have shown another form
of movable base wherein the base 2 is secured to the base ring 21 by the inter-
mediate pieces 24 and pins 23, the ring 21 being held within the shell by the
threaded ring 11 having the centering lugs 11. The entire base is thus made
capable of inward movement under the pressure of the gases of the expelling
charge.
In the several forms of our invention it will be apparent that should any
explosion of the detonating charge occur prematurely the pressure generated
thereby would be expended against the discs 7 and this pressure would hold said
discs in place, and prevent communication of the flame to the main or bursting
charge. This does not, however, provide for holding the discs in place during
the handling of the shell, or at any other time, except during the premature
explosion, and therefore we have provided positive mechanical means for holding
the discs in place consisting of the pins 8, the latter being held in place in one
construction by contact of their heads with the walls of the gun barrel and in
the other construction by the counter pins. We regard our invention as cover-
ing broadly any equivalent mechanical means for retaining the movable partitions
in place and capable of being displaced or released by natural forces operating
during the flight of the shell.
Obviously some of the features of construction may be modified in other respects
than those hereinbefore particularly described, as for example, we have described
a fuse which is transversely divided by movable discs or partitions so as to afford
both a detonating chamber and a safety chamber, and we prefer in all cases to
employ said detonating chamber, as thereby the detonating charge is introduced
into the body of the main bursting charge and is thereby in the best situation
for securing a perfect and certain detonation of the main charge, but that portion
of the fuse formed by the cup like part and which is secured to the base 21
may be omitted and the detonating charge with its cap or cartridges may be
placed within such safety chamber, as shown in Figure 5, and when the discs
or plates are thrown out after the discharge of the shell from the gun the detonat-
ing charge will pass into the opening thereby provided, thus coming in con-
tact with the main bursting charge of wet gun cotton and upon the impact of
the shell will be exploded.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is:
1. A safety fuse for high explosive shells characterized by the provision of a
chamber to contain the detonating or primary charge, and a movable partition
normally separating and isolating said charge, and movable by centrifugal force
during the flight of the shell whereby to permit the priming charge to pass into
proximity to the main or bursting charge, substantially as described.
2. A high explosive shell provided with a main chamber containing a bursting
charge, a separate or isolated chamber containing the priming or detonating
charge and a movable partition normally separating said chambers and movable
by centrifugal force during the flight of the shell to permit the priming charge
to pass into proximity to the main charge, substantially as described.
3. A high explosive shell comprising a chamber for the main or bursting charge,
a separate or isolated chamber for the priming or detonating charge, a partition
between said chambers adapted to open communication between them when
actuated by the centrifugal force due to the flight of the shell and means for

page_text: locking said partition in a closed position, said locking means being also adapted
to be freed or released by the discharge of the shell from the gun, substantially
as described.
4. A shell for high explosives provided with a chamber for the main or burst-
ing charge, a separate or isolated chamber containing the priming or detonating
charge, a passage connecting said chambers, a partition normally closing said
passage, locking pins normally holding said partition in its closed position, and
retaining devices for said locking pins adapted to be released on the discharge
of the shell to free said locking pins and permit lateral movement of said partition,
substantially as described.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.