Improvements in Percussion Fuzes for Explosive Projectiles.
Year: 1893

page_text: Date of Application, 1st Aug., 1893-Accepted, 14th Oct., 1893
COMPLETE SPECIFICATION.
Improvements in Percussion Fuzes for Explosive Projectiles.
I, JOSEPH CLARK, of 402, Montgomery Street, City and County of San
Francisco, California, United States of America, Gentleman, 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 has relation to explosive projectiles and the object of the inven-
tion is to insure the explosion of the shell at the instant that it strikes an object.
In the practical use of projectiles of this character, it is a matter of fact that a
very large proportion of shells projected from ordnance or otherwise, fail to
explode and in that class of shells where the cap or primer is at the point failures
often occur because the shell does not strike the object with its point. In that
class of shells which are provided with time fuses an accurate determination of the
proper length of fuse for certain distances through which the shell is to be projected
and imperfections in the fuse contribute to failure in many instances. The employ-
ment of a movable plunger or hammer has been essayed for the purpose of utilizing
its rebound when the shell strikes upon its point for the purpose of striking a cap
having communication with the explosive material within the projectile, but in
these instances no provision has been made for insuring an explosion in case the
shell should fail to strike the object with its point and this failure to so strike an
object is exceedingly common so that notwithstanding all that has heretofore been
essayed in this character of devices, the object sought; that is absolute certainty of
explosion regardless of the portion of a shell which comes in contact with an object,
is still unattained. Devices heretofore used are also liable to be accidentally
brought into action.
By my invention I secure absolute certainty of explosion and absolute safety
against accidental explosion.
Referring to the drawing:
Fig. 1 represents a longitudinal section of a explosive shell with my improved
exploder applied thereto.
Fig. 2 is a longitudinal vertical section of the exploder ready for action.
Fig. is a substantially central transverse section of the exploder.
Like letters refer to like parts in all the figures.
A represents a shell which may be of any desired construction and B represents
an explosive compound within the shell which compound may also be of any
nature, character or name as desired and placed within the shell in any suitable
manner. My invention has no relation to any shell or explosive compound employed
therein.
C represents my exploder and it consists of a shell which may be of any desired
contour and can be cylindrical as illustrated in this case. It has a bottom or rear
head C which may be threaded into the shell or cast or otherwise formed
integrally therewith. The bottom C' has a counter-sink or recess or it may be a
hole C therein which receives a projection D¹ formed on the hammer or plunger D.
Any desired number of nipples C³ either plain or screw threaded to retain a cap
or primer by friction or by coacting screw threads in the cap are arranged in any
desired manner within the shell C with their cap-bolding ends pointed inwardly.
A convenient form of connection for the nipples with the shells is by screw
threads C. Each of the nipples has an opening C³ to communicate with the
explosive material B within the shell or projectile in which the exploder is
embedded. may employ other forms of nipples, in fact any form that may be
preferred. I have illustrated in the head or closing plug C of the exploder a form
of nipple which has the flash opening C³ and a recess C7 to receive that form of cap

page_text: known as a primer. I have also provided a supplementary hammer E held away
from the primer by a coiled spring E', so that when the main hammer or plunger Ď
comes in contact therewith the primer will be exploded by the projecting lug E' on
the hammer E. This lug E2 would be dispensed with in case an ordinary nipple
were used instead of a primer nipple and the face of the hammer E would be plain
as shown at the lower one of the two hammers E in Fig. 2.
The plunger or hammer D is supported centrally but yieldingly within the shell C
of the exploder. This yielding support may be secured by the use of springs of
any character and I have shown one form which consists of coiled springs and these
are, in this instance, arranged radially and they may be seated for a desired depth
in the recesses D' formed in the hammer. The number and stiffness of the springs
may be as desired and the latter characteristic may be far beyond what is necessary
for the mere support of the plunger towards any of the nipples projecting inwardly
from the shell of the exploder. The plunger is made of any suitable material which
will give it a desired weight sufficient to be forced against the nipple or against one
or more of any of the nipples so as to explode the cap or caps thereon. A wide
margin exists in the tension of the spring because of the much greater force exerted
when the shell strikes an object after it has been projected from a cannon, rifle or
other piece or ordnance. The tension of the spring is therefore permissible to
such an extent that the accidental dropping of a shell provided with my exploder
will not cause a plunger to contact with any of the nipples in the exploder. A
spring may be employed between the front end of the plunger and the inner
face of the closing plug C of the shell to insure against the forward movement of
the plunger fron accidental causes but the friction of the springs F upon the inner
wall of the exploder shell will ordinarily be sufficient to prevent such a movement
of the plunger. It will be observed that as a shell is projected and while it is still
within the gun the rear end of the plunger D presses with great force (its weight
multiplied by the momentum of the shell) against the bottom of the exploder
so that the liability of the plunger coming in contact with any of the nipples is
exceedingly limited and the broader the base of the plunger the less of such
liability exists; still the spring F may be employed if desired to increase the
safety or accidental displacement of rebounding of the plunger.
The rear end of the plunger is rounded as at D³ for the purpose of facilitating a
radial movement of the front end of the plunger so that said end may come in
contact with nipples in the forward part of the exploder.
As thus far described it will be seen that in my invention there is embedded in
the explosive material of a projectile an exploder comprising a shell having nipples
projecting inwardly and having supported therein à plunger the manner of its
support being such that it may move in any direction excepting in a right line
rearwardly in the direction of the movement of the projectile. With this con-
struction it is not possible for a shell, i.e. a projectile to strike an object in any
direction with any portion of the projectile in contact therewith without causing
the plunger to explode one or more of the caps upon its nipples.
My exploder may be arranged within a shell and secured therein by any suitable
means or in any suitable manner. It may be simply embedded in the explosive
material or the shell may be provided with one or more partitions, diaphragms or
spiders G, with or without openings G' and with or without sockets G2 for receiving
and supporting the ends or periphery of the exploder shell. The projectile may be
divided into sections A' or have a removable bottom A² or may be of any other
well known construction that will facilitate the introduction of the exploder and
the explosive compound.
For purposes of safe transportation and handling and to absolutely prevent an
accidental movement of the plunger and therefore the accidental explosion of a
projectile provided with my exploder, I have devised a securing bolt H which is
threaded into and through the plug C and which is adapted to enter a recess D*
in the front end of the plunger so that when by any suitable means the bolt H is
passed through the plug or head C and into the recess D', it firmly locks the

page_text: plunger against the bottom of the exploder and together with the projection D¹,
maintains the plunger rigidly and centrally within the exploder so that it is utterly
impossible for the plunger to contact with the nipples.
In order to insure the unlocking of the plunger before a projectile provided with
my exploder is seated in a gun, I have provided on the bolt H, an angularly-
disposed handle H' which projects in one or more directions beyond the periphery
of the projectile so that it is impossible to place such a projectile into a gun without
removing the bolt H. The handles H' also serve as a ineans for carrying the shells
from place to place. In order to insure against the accidental explosion and
abrasion of the material within the projectile, a tube I of paper or other material
may be inserted within the shell and extending from the point to the opening in the
plug C into which the bolt H is screw threaded. If desired a plug similar to
the plug As through which the bolt H passes may he inserted at the point of the
projectile so as to close said opening after the bolt H is removed from the exploder
and projectile or a simple hole at the point of the projectile for receiving the bolt H
may be employed if desired, an ordinary nipple with a cap on the outer end and
communicating with the interior explosive material may be, after the bolt H is
removed, mounted upon the point of the projectile so that if the shell strikes upon
the point its explosion is further insured.
As before indicated I may use any form of nipple in the side or front of the
exploder those shown in the front being used indiscriminately in the sides or front
and vice versu.
The hammer E has its body smaller than the head thereof passing
through an aperture e, in the plug or head C, and a plug E³ is screwthreaded into
the head C and in this plug the nipple C³ is screwthreaded, the coiled spring E¹
encircling the nipple and bearing against the head of the hammer.
While the projection D' of the plunger serves to enter the recess C² when the
bolt H, see Fig. 1, is employed to lock the plunger against any movement still it is
apparent that a plain flat ended plunger without a projection D' bearing against a
plain unrecessed bottom C¹ will be firmly locked by the bolt H; therefore while
the projection D¹ and recess C are preferred still the invention is not limited to
these details.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim, is-
An exploder for projectiles constructed and operating substantially as herein
shown and described.
day of July 1893.
F. BOSSHARDT & Co.,
4, Corporation Street, Manchester, Agents to Applicant.