Improvements in Safety Fuses or Detonators for Explosive Projectiles and their Fittings.
Year: 1899

page_text: Date of Application, 26th May, 1899-Accepted, 2nd Sept., 1899
Improvements in Safety Fuses or Detonators for Explosive Projectiles
and their Fittings.
I, HARRIS PRIULI HURST, of No. 1103, East Capitol Street, Washington, D.C.,
United States of America, Inventor, 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 or detonators for explosive shells, pro-
jectiles and their fittings, and the method and means of storing and using power
to operate the safety devices of the fuses or detonators and projectiles.
The object of the invention is, first, to produce a safety device that will
positively protect the main or bursting charge carried by the projectile, under all
conditions, upon an accidental or premature explosion of the explosive material of the
fuse or detonator; and, secondly, to provide means for storing power within the
device to operate the isolating barrier or partition or other mechanism used to
insure the main or bursting charge against accidental or premature explosion or
detonation; and, thirdly, to simplify and improve the construction of safety
fuses or detonators and their fittings.
The invention consists in a construction by which the explosive material of
the fuse or detonator is isolated from the main or bursting charge, carried in the
projectile, by a novel device arranged as a barrier or partition, axially supported
or adjusted in a roundish or other shaped housing in a holder, normally inter-
posed between the main or bursting charge and the explosive material of the
priming or detonating fuse charge. Positive means to hold the barrier or
partition in the closed position and move the same by stored power, only after the
projectile has been fired from the gun, are provided in the form of simple mechanical
appliances, or pressure devices, operated by hand, or by the action of the gases
of the propelling charge, acting upon the mechanism and storing up the power
to move the barrier or partition during the flight of the projectile or torpedo.
Another feature provides for a barrier or partition having therein a chamber
for a charge of priming or detonating fuse material, which may constitute alone
the explosive part of the fuse or detonator, or be one of two or more different
kinds of explosive composing or contained in the fuse or detonator; a separate
or isolated chamber being provided, if desired, for each of the different explosives
which may be used in the fuse or detonator; the fuse holder constructed with, or
attachable to, the projectile.
I accomplish these results in the following manner, reference being had to the
drawings, in which:
Figure 1 is a longitudinal section, partly in elevation, showing my invention
applied to the base of the shell or projectile, and illustrating the three isolated
chambers of my safety fuse or detonator, the barrier or partition being in
the normal or closed position, before the shell or projectile is fired from the gun.
Figure 2 is a similar view, omitting the extreme ends, showing the position
of the barrier or partition after the shell or projectile has been fired from the gun,

page_text: the three chambers of the fuse or detonator being thrown into one continuous
fuse-way or channel.
Figure 3 is a detail of the hand operated power storing device, on an enlarged
scale, shown in Figures 1 and 2.
Figure 4 is a detail of the locking device, on an enlarged scale, used with
Figure 3 and shown in Figures 1 and 2, to store up power to turn the barrier or
partition and throw open the fuse-way or channel.
Figure 5 is a detail of the pivot or trunnion block, shown in Figures 1 and 2,
the pivot or trunnion being in the normal position, i.e., the position it occupies
when the barrier or partition is closed.
Figure 6 is a modification of Figure 1, the rear wall of the barrier or partition
and one of the chambers of the fuse or detonator, as previously illustrated, being
omitted.
Figure 7 is a detail, on an enlarged scale, of a modification of Figure 3, and is
shown in Figure 6.
Figure 8 is a detail, on an enlarged scale, of a modified locking device, and is
shown in Figure 6, and
Figure 9 is a modification of Figure 1, omitting the tube or stock, and
utilizing the propelling gases to store power and operate the mechanism to move
the barrier or partition.
Referring to the drawing, letters of reference are used to designate the various
parts.
The shell or projectile, A, and the fuse fittings may be of any desired con-
struction and of steel or other suitable material, and the main or bursting
charge chamber, B, may contain wet guncotton or any other suitable explosive,
and the chamber is closed by a screw plug, C, and attached thereto or integral
therewith and projecting into chamber, B, is a detonating chamber, D, preferably
of tubular form. Extending from the rear of plug, C, and attachable thereto,
or integral therewith, is a holder, E, in which is a roundish or other shaped
housing for the barrier or partition, F, axially supported or adjusted therein.
A circular copper bushing, G, is screwed into the mouth of the detonating
chamber as a gas check. The holder, E, is screw threaded at the rear end and is
closed by the forward end of the screw threaded tube or stock, E', into the rear
end of which is screwed the guide, E, closed at the rear end by a screw
plug, E An annular chamber, H, is shown around the guide, and in this
chamber is a locking ring, H¹, the forward end projecting into an annular
channel, H, cut in the rear portion of the barrier or partition, F, and locking
it against motion, the ring being held in this position by a soft or brittle metal
shear pin, I, having a hard metal screw plug or head, I¹, passing through the
walls of the tube or stock and the ring. The spherical or rounded barrier or
partition, F, has a hole through its center, forming a chamber, D', and the barrier
has on its lower side a fixed pivot or trunnion, J, one-half of which is cut away,
as shown in Figure 5, and is fitted in a slot, K, in the wall of the holder and held
in position by the block, K', having a projection, K", laying against the cut
away side of the pivot or trunnion, J. The block is held in the slot by the wall
of stock, E. In the upper side of the barrier is formed a recess, L, the lower
portion of which terminates in a recess, L', of smaller diameter. In the larger
recess is a coiled spring, M, one end of which is anchored in the dovetailed
slot, N, in the wall of the barrier. Through the upper wall of the holder,
opposite the slot, K, is an opening, O, in one side of which is a channel, O¹.
Through opening, 0, is placed an adjustable pivot or trunnion, J¹, having a
squared head or stem, P, and a slotted or bifurcated lower end, P¹, and a
channel, P, on the upper portion of one side. When the pivot or trunnion
is placed in position, the free end of the spring, M, enters the slot, P¹, and is
held by an enlargement on the end of the spring, as shown. Opening, 0, is
closed by a screw plug, Q, which may be provided with a washer or gas check,
and, when the plug is removed, a winding key is placed over the squared head

page_text: or stem, P, and the pivot or trunnion, J¹, turned by the key until the spring is
wound and put under the desired tension, and, when channel, P, registers
with a corresponding channel, O¹, in the upper part of the wall of
opening, 0, a pin, P, is run down these channels, as shown in
Figure 4, thus securely holding the pivot or trunnion from motion and retaining
the spring under tension; and, when the plug, Q, is screwed into position, it
bears upon the pin and retains it in place. As stated, the barrier is securely held
from rotation by the locking ring, H.
By removing plug, E, the fuse or detonator encased charge, R, of any prefer-
able construction and material, may be placed in position or removed from
the guide, El. An annealed copper spring, R¹, may be attached to the fuse or
detonator casing and plug, E, or the casing may be held by a shear pin, as
shown in dotted lines. The barrier lies across the fuse-way.
The operation of my safety fuse or detonator is as follows: When the shell
or projectile is fired from the gun, the locking ring, H¹, shears off the pin, I, and
sets back in the annular chamber, H, and becomes wedged and held fast in the
rear end of the chamber, the guide being enlarged on its lower exterior for this
purpose. The fuse or detonator charge, R, also retires rearward, compressing the
copper spring, which takes up a part of the initial or firing shock, and has no
return elasticity. The barrier, F, when released by the locking ring, is held,
during the acceleration of the shell or projectile, by the set back pressure, which
is until after the shell or projectile has left the muzzle of the gun. This set
back pressure may be borne entirely by the walls of the tube or stock, E¹, or by
the trunnions, or partly by both the wall and the trunnions, and, when this
pressure is relieved or released, the tension of the spring, M, turns the barrier
around the pivot or trunnion, J¹, one-fourth of a revolution, or until the barrier
is stopped by the projection, K, on the block arresting the rotation of the fixed
pivot or trunnion, J, the cut away portion then laying against the forward face
of the projection on the block, as shown in dotted lines, Figure 5. The reserve
tension of the spring holds the barrier in this position. The chamber, D¹, being
now in registering alignment with chamber, 1), and the fuse-way or channel being
open, as shown in Figure 2, the priming or detonating charge, R, may pass into
proximity to the main or bursting charge carried in chamber, B. Upon retarda-
tion or impact of the shell or projectile, the encased charge, R, flies forward and
the cap, S, is fired by the pin or nipple, S', in the forward part of chamber, D,
and the fuse or detonator charge being exploded by the cap, the main or bursting
charge in the shell or projectile is exploded or detonated by the exploding
material of the fuse or detonator. The walls of detonating chamber may be
thinned, channeled or grooved, as shown in dotted lines. The barrier, F, "may
be weighted or be made so as to balance in its housing or on its adjustments or
axial bearings and the holder housing may envelop it closely or have more or
less free space, as shown, the walls at the entrance to the detonating chamber
being curved or rounded to conform to the spherical or rounded barrier, or face
of the barrier, as it normally closes the fuse-way or channel. Other releasing
or locking means may be used.
In Figure 6 the barrier or partition, F1, has a single curved or rounded wall,
instead of the double wall shown in Figure 1, and the chamber within the
barrier is omitted, the guide carrying the fuse or detonator charge, R, by this
arrangement being brought forward, economizing space, and is adapted to a
fuse or detonator charge contained in a single package or case, as shown. In
this construction the trunnions, J and J, are placed in position through
openings, O, in the walls of the holder, and screwed firmly into the barrier. The
mechanism for locking and turning the barrier, F1, may be the same as that
heretofore illustrated and described. An annular chamber may be formed around
the guide, as shown in dotted lines. A spring, M¹, in recess, L", is secured in
the slot, N, in the wall of the holder, Figure 7, and the curved end of the spring
is passed through a slot, P', in trunnion, J. The curved end is intended to

page_text: anchor the spring, but other means may be used for this purpose. The spring
is put under tension by screwing the trunnion into the barrier and, when the
barrier is turned so as to cover chamber, D, as shown, it is held by a lock, T,
having a weighted center and radiating spring arm anchored in channels, T¹, in
the holder walls. The lock has a central hole through which a key is placed over
the squared head or stem, P, of the trunnion when it is screwed into position,
the teeth, U, on the lock falling into channels, U¹, in the head of the trunnion
on either side of the squared head or winding stem. This locks the barrier in
the closed position, as shown, and, when the plug, Q, is screwed into position,
the arms are prevented from outward motion.
The operation of my fuse or detonator, as illustrated by Figure 6, is as follows:
When the projectile is fired from the gun, the set back pressure of the barrier, F¹,
upon the trunnions holds the barrier in the closed position until the pressure is
relieved or released, which is not until the projectile has left the muzzle of the
gun, the rotary motion of the projectile then swings by centrifugal force the
weighted center of lock, T, outwardly, as shown in dotted lines, thus withdrawing
the teeth, U, from the channels, U, in the trunnion, which, when released, is
rotated by the tensioned spring, and the trunnion, being screwed fast into the
barrier, turns the barrier to one side of the fuse-way or channel, and upon
retardation or impact of the projectile the cap, S, is exploded by the nipple, S',
in the detonating chamber, and the main or bursting charge in the projectile
is exploded or detonated by the gases of the exploding fuse or detonator charge.
More or less free space may be left around the barrier, as shown. A weight
may be placed in the wall of the holder opposite the position barrier I assumes
in opening to maintain the equilibrium of the projectile. In this design the
guide is attached to the loading plug, E, and the priming or detonating fuse
charge, R, may be stored, in this form, and screwed into the projectile when ready
for use.
I show in Figure 9 a modification of Figure 1, the stock being omitted and the
fuse or detonator charge, R, is placed in chamber, D', in the barrier, F, which is
held in the closed position by the arm, V, attached to the barrier and to the
coiled spring V1, the spring being also attached to the elbow of the piston bar, W.
The forward end of the piston is tubular, terminating in a mouth with thin walls
fitting closely into the chamber, W1, the entrance to which is closed by a screw
plug, X, having a small hole, X', through the center and plugged with lead.
When the piston pulls upon the spring and presses the arm against the walls of
chamber, W, a shear pin, Y, is screwed through the holder wall and the point
engages with the shoulder, Y', on the piston, locking the mechanism against
motion. A fluid, Z, as, for instance, glycerine, or wax, may be placed in the
tubular cavity of the piston. Chamber, W, is closed by a plug, W, projecting
against the piston bar.
A loading plug, E, to place or withdraw the fuse or detonator charge, R, is
provided and dotted lines indicate pivots or trunnions of the barrier, which is
spherical, substantially in form, and enveloped closely by the globular housing
of the holder.
The operation of my fuse or detonator, as illustrated by Figure 9, is as follows:
When the gun is fired, the gases from the propelling charge drive the lead plug
through the small hole, X', in the plug, X, and enters the chamber, W, and the
piston shears the pin, Y, and is driven forward by gas pressure until the shoulder
abuts against the plug, W, as shown in dotted lines, the fluid or wax and the
thin walls acting as a gas check and preventing the flow of gas beyond the piston
into chamber, W. The set back pressure causes the barrier to remain unmoved
while the piston is pushed forward. The spring is drawn out by the elbow end
of the bar and held under tension, the gas pressure wedging the piston in the
chamber by spreading the walls of the tubular portion of the piston so as to
prevent its return. When the set back pressure is relieved or released, which is

page_text: not until the projectile has left the muzzle of the gun, the spring draws the
arm, V, forward, thus turning the barrier upon its axial supports and bringing
the chamber, D', in alignment with chamber, D, the tension remaining in
the spring holding the barrier in this position. Upon retardation or impact
of the projectile the fuse or detonator charge, R, is exploded by the cap, S,
coming in contact with the nipple, S¹, in chamber, D), and the exploding fuse or
detonator charge explodes or detonates the main or bursting charge carried
in the projectile. A device to cut off the gas, when sufficient power has been
stored, may be used, or the escape of stored gas, as the projectile leaves the
muzzle of the gun, may be used to open the fuse-way or channel. The mechanism
for locking or retaining and the devices for moving the barrier may be applied to
both axial supports or adjustments of the barrier or partition. This would
strengthen the mechanism and give two sources of stored power, instead of one.
Many mechanical devices may be used to store power, either by hand, or by
the set back pressure causing a weight to compress a spring, or by gas pressure
from the propelling charge, and the pressure can be regulated and controlled to
open or move any suitable barrier or partition, adjusted in any suitable manner;
and I do not limit myself to any particular construction, or mode or manner of
operating the same.
The fuse or detonator explosive charge or charges may be of any desired size,
shape and material, as, for instance, fulminate of mercury alone, or in combina-
tion with guncotton or any other suitable explosive, to meet the requirements of
the particular kind of explosive used in the projectile as a bursting charge.
The barrier or partition may be of any suitable material, size and shape and
supported or adjusted in any suitable manner. The rear half of the barrier
or partition, F, may be of copper, or other yielding metal, and the front part
of steel.
My invention can be easily applied to shells, and projectiles in use, making
use of any of the well known explosives as a bursting charge for the projectile
and for use in the fuse or detonator. The tube or stock is made with relatively
weaker walls than the holder, or the walls of the stock may be purposely weakened
so that, upon an accidental or premature explosion of the fuse or detonator
charge or charges, the barrier, F, which, if made of two metals, the hard metal
portion of the barrier will be driven against the copper bushing, effectually
preventing the forward flow of gas; and remaining in position-the tube or stock
being ruptured and separated from the holder. Or the stock may be constructed
of elastic or tenacious, cohesive material, permitting its rupture without separat-
ing it from the holder. The main or bursting charge carried by the projectile,
in all events, is securely protected against the accidental or premature explosion
of the explosive material of the fuse or detonator.
My spherical or rounded barrier I consider of great advantage over other forms
of barriers, the maximum strength being secured in the barrier and the projectile
closure or base piece by this construction. In some instances it may be advisable
to place my safety fuse or detonator within the projectile, or in the head of the
projectile, it being adapted to either position.
It is apparent many modifications may be made of my invention without
departing from the letter, spirit and scope of the same.
Stored power may
operate the barrier locks.
I am not aware that any one has heretofore made, shown or described a
fuse or detonator provided with means to store. power to operate the safety
devices thereof; nor a safety fuse or detonator having three separate isolated
compartments; or an axially supported or adjusted barrier or partition normally
closing the fuse-way or channel to the main or bursting charge carried by the
projectile; or a balanced barrier or partition; or a spherical or rounded barrier
or partition; and I desire protection broadly for my invention without regard
to the means I employ to accomplish the desired result.

page_text: Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is
1. A fuse or detonator, for explosive projectiles, provided with an isolating
barrier or partition interposed between the explosive material thereof and the
main or bursting charge in the projectile, and devices operated by stored power to
move said barrier or partition during the flight of the projectile.
2. A fuse or detonator, for explosive projectiles, provided with a fuse-way
or channel, means to close said fuse-way or channel, and devices operated by
stored power to open said fuse-way or channel during the flight of the projectile.
3. A fuse or detonator, for explosive projectiles, provided with an isolating
barrier or partition interposed between the explosive material thereof and the
main or bursting charge in the projectile, and a pressure device to move said
barrier or partition during the flight of the projectile.
4. A fuse or detonator, for explosive projectiles, provided with a barrier
or partition normally closing the fuse-way or channel thereof, and means to
store power to move said barrier or partition during the flight of the projectile.
5. A fuse or detonator, for explosive projectiles, constructed with a barrier
or partition normally closing the fuse-way or channel thereof, and provided
with stored power to move said barrier or partition during the flight of the
projectile.
6. A fuse or detonator, for explosive projectiles, provided with a balanced
barrier or partition normally closing the fuse-way or channel thereof, and means
to move said barrier during the flight of the projectile.
7. A fuse or detonator, for explosive projectiles, the fuse-way or channel
thereof forming, in the normal position, a barrier or partition between the
explosive material of the fuse or detonator, and the main or bursting charge of
the projectile.
8. A fuse or detonator, for explosive projectiles, the fuse-way or channel
thereof normally closed by a barrier or partition having a fuse-way or channel
therein.
9. A fuse or detonator, for explosive projectiles, the fuse-way or channel
therefrom normally closed by a barrier or partition in engagement with the
side walls of the holder thereof, said barrier or partition revolving clear of the
fuse-way or channel during the flight of the projectile.
10. A fuse or detonator, for explosive projectiles, the fuse-way or channel
thereof normally closed by a revolving barrier or partition in engagement with
the side walls of the holder thereof, means to lock said barrier or partition in
the closed position, and means to remove said barrier or partition from the mouth
of the fuse-way or channel during the flight of the projectile.
11. A fuse or detonator, for explosive projectiles, provided with a holder,
the fuse-way or channel therefrom normally closed by a barrier or partition held
therein by axial supports on which the barrier or partition turns in opening the
fuse-way or channel during the flight of the projectile.
12. A fuse or detonator, for explosive projectiles, provided with a trunnioned
barrier or partition normally closing the fuse-way or channel therefrom, and
means to move said barrier or partition during the flight of the projectile.
13. A fuse or detonator, for explosive projectiles, divided into three compart-
ments or chambers, the walls of the central chamber isolating the adjacent
chambers, and means to move said walls, during the flight of the projectile,
and open communication for the passage of the explosive material of the fuse
or detonator.
14. A fuse or detonator, for explosive projectiles, a holder therefor, a fuse-
way or channel therefrom, a spherical or rounded barrier or partition normally
closing said fuse-way or channel, and means to move said barrier or partition
on its axis and open said fuse-way during the flight of the projectile.
15. A fuse or detonator, for explosive projectiles, a holder therefor, a fuse-

page_text: way or channel therefrom, a barrier or partition normally closing said fuse-way
or channel, a recess in said holder, and mechanism therein to move said barrier
or partition during the flight of the projectile.
16. A fuse or detonator, for explosive projectiles, having three normally
closed chambers, and means to throw said chambers into one continuous chamber.
17. A fuse or detonator, for explosive projectiles, provided with a holder
carrying a guide, an explosive therein protected by a chamber consisting of an
axially adjusted barrier or partition normally isolating said explosive, and means
to open the fuse-way or channel therefrom during the flight of the projectile.
18. A fuse or detonator, for explosive projectiles, provided with a barrier or
partition in the fuse-way or channel, and a guide therethrough for the priming
or detonating fuse charge therein.
19. A fuse or detonator, for explosive projectiles, contained in a holder having
compartments or chambers isolated by two barrier walls or partitions enclosing
there-between the central compartment.
20. A fuse or detonator, for explosive projectiles, having the explosive material
thereof carried in a fuse-way or channel normally divided into three separate
compartments or chambers.
21. A fuse or detonator, for explosive projectiles, provided with a trunnioned
or pivoted adjustable barrier or partition normally closing the fuse-way or
channel thereof, and a spring in engagement with said trunnion or pivot and
moving said barrier during the flight of the projectile.
22. In combination with a fuse or detonator, a barrier or partition for closing
the fuse-way or channel, and a pressure device to move said barrier or partition
from said fuse-way or channel.
23. A projectile provided with a main chamber, a detonating chamber, and
two separate fuse compartments isolated from each other by the movable walls
of the central fuse compartment.
24. A projectile having separate chambers for the main charge and the fuse
or detonator, a barrier normally separating said chambers, and means to move
said barrier, said means consisting of power stored up and liberated when the
projectile has been propelled from the gun.
25. projectile carrying a fuse containing priming or detonating material
carried in a guide, a barrier or partition interposed between said explosive and
the main or bursting charge contained in the projectile; said barrier or partition
carrying means to revolve itself clear of the fuse-way or channel during the flight
of the projectile.
26. A projectile provided with a fuse-way or channel, and a recess in the
wall of the fuse holder, in combination with a barrier or partition normally
closing said fuse-way or channel, and mechanism in said recess to move said
barrier or partition during the flight of the projectile.
27. A projectile provided with a fuse-way or channel, in combination with an
axially supported or adjusted curved or rounded barrier or partition normally
closing said fuse-way or channel, and a locking ring in engagement with said
barrier or partition and moving out of engagement therewith when the projectile
is propelled from the gun.
28. A projectile provided with a fuse or detonator having three isolated com-
partments or chambers normally non-communicating with each other, and means
to open communication between said compartments or chambers during the flight
of the projectile.
29. A projectile provided with a fuse-way or channel, in combination with a
barrier or partition normally closing said fuse-way or channel, and a tensioned
spring to move said barrier or partition clear of said fuse-way or channel during
the flight of the projectile.
30. In, or in combination with a projectile, a fuse-way or channel, a barrier
or partition therefor, a locking or releasing device to hold said barrier or
the fuse way
partition across
or channel, and a stored power device

page_text: adapted to move the barrier or partition and open the fuse-way or channel when
the locking or retaining device releases said barrier or partition.
31. In, or in combination with a projectile, a fuse-way or channel, a barrier
or partition therefor, a locking or releasing device to hold said barrier or partition
across the fuse-way or channel, and a stored power device adapted to move the
barrier or partition and open the fuse-way or channel when the locking or
releasing device is actuated by centrifugal force and releases said barrier or
partition.
32. In, or in combination with a projectile, a fuse-way or channel, a barrier
or partition therefor, a locking or releasing device to hold said barrier across
the fuse-way or channel, and a spring under tension or compression adapted
to move the barrier or partition and open the fuse-way or channel when the
locking or releasing device releases said barrier or partition.
33. For use with an explosive projectile, a spherical or rounded barrier or
partition carried in a globular or rounded housing, normally isolating the main
or bursting charge from the fuse or detonator thereof.
34. For use with an explosive projectile, a rounded barrier or partition having
a fuse-way or channel therethrough.
35. For use with an explosive projectile, a soft metal bushing at the entrance
of the detonating chamber therein.
36. For use with an explosive projectile, a fuse holder having a recess carrying
a mechanism for moving a barrier or partition and opening the fuse-way or
channel therefrom during the flight of the projectile.
37. For use with an explosive projectile, an axially adjusted revolving barrier
or partition carried by the fuse holder and normally closing the fuse-way or
channel therefrom.
38. For use with an explosive projectile, a barrier or partition closing the
fuse-way or channel and provided with devices actuated by stored power to move
said barrier or partition.
39. The method of protecting a projectile charge, which consists in isolating
the fuse or detonator by a barrier or partition moving by stored power to open
communication between said charge and the fuse or detonator during the flight
of the projectile.
40. The method of constructing a safety fuse or detonator for explosive pro-
jectiles, which consists in normally closing the fuse-way or channel thereof and
storing power to open said fuse-way or channel.
D
J
is th day of May 10.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.