IMPROVEMENTS IN SHRAPNELL SHELLS AND THE PEROUSSION FUZES FOR THEM, SUCH PERCUSSION FUZES BEING ALSO APPLICABLE TO OTHER SHELLS.
Year: 1879

page_text: LETTERS PATENT to Benjamin Berkley Hotchkiss, of 38, Southampton
Buildings, Chancery Lane, London, for the Invention of "IMPROVEMENTS IN
SHRAPNELL SHELLS AND THE PEROUSSION FUZES FOR THEM, SUCH PERCUSSION
FUZES BEING ALSO APPLICABLE TO OTHER SHELLS. "
PROVISIONAL SPECIFICATION left by the said Benjamin Berkley Hotchkiss
at the Office of the Commissioners of Patents on the 15th October 1879.
BENJAMIN BERKLEY HOTCHKISS of 38 Southampton Buildings Chancery Lane
London. "IMPROVEMENTS IN SHRAPNELL SHELLS AND THE PERCUSSION FUZES
FOR THEM SUCH PERCUSSION FUZES BEING ALSO APPLICABLE TO OTHER SHELLS."
The object of this Invention is to simplify the construction of the shrapnell shell
by obviating the necessity of using the fuze passage from the nose of the shell to
the powder charge in the base by employing a percussion fuze of the kind described
in the base of the shell and also to produce a fuzo for this kind of shell or others
which is absolutely effective completely safe during the transport of the projectiles
to which the fuzes are attached and which does not require any manipulation
to arm tho fuze before the discharge of the projectile. For this purpose one of the
principal parts of the fuze, that is, either the firing pin or the primer or priming is
carried on a comparatively heavy body which under certain circumstances is capable
of a short movement or displacement in its caso on a line parallel to the axis of the
projectile. This heavy body or plunger in consequence of its inertia effects first
the arming of the fuze at the moment of the discharge of the gun and afterward
the ignition of the primer when the projectile is suddenly arrested by resistance to
its flight whilst before the discharge the plunger is firmly held in such position as
to prevent the accidental contact of the firing pin with the primer or vice versa,
This plunger is composed of three parts first a body of soft metal such
as lead, second a case or envelope of hard metal, for instance brass in which the
soft metal is partly enclosed and third a central pin of hard metal the front end
of which either terminates in a point acting as the firing pin or carries tho primer.
The rear end of this central pin projects beyond the bottom of the plunger whilst
its front end is sunk a little in the face of the plunger; the entire length of this
compound part is so calculated that when it is inserted in the fuze case and when

page_text: the screw cap is in place, the firing pin point cannot touch the primer and that it
cannot displace itself without a considerable shock. The surface of the central pin
is roughened by indentations projections or scrow thread so as to afford a
sufficient hold to the surrounding lead to prevent any accidental displacement. At
the moment of the discharge of the gun the plunger, in consequence of its inertia
slides back on its central firing pin until it strikes against the bottom of the fuze
case, the point itself then standing above the enclosing soft metal ready to be
projected on to the fulminate or primer. The force of this shock is so great that
the lead again closes tightly around the pin and when the projectile then strikes
against any obstacle the inertia of the plunger is overcome and the plunger acting
in the opposite direction drives this compound part, that is, the enclosing case the
soft metal and the firing pin forward producing thus the ignition of the primer, the
flame of which causes the ignition of the powder charge in the projectile. Besides
the facilities already mentioned which aro derived from the use of lead or other
soft metal for forming the main body of the plunger the advantage is obtained that
the latter is not liable to rebound whereby a premature explosion might. be
produced.
In certain cases the percussion which causes the explosion is effected with more
certainty by mounting the fuze at the butt end of the projectile. For instance when
a projectilo strikes laterally instead of with its point, a fuze arranged in the front
or nose end of the projectile is liable to fail whilst a butt fuze, even under such
circumstances detonates alunost invariably; and besides such arrangement renders
the construction of the projectile simpler and less costly. Therefore this new fuze
is specially adapted for serving as a butt fuze.
The parts thus described are enclosed in a fuze caso of bronze or other metal
constructed to screw into the shell to be fired which is provided with a projecting
flange acting as a gas check and which is a part of the fuze case.
The head of the fuze case is constructed of a larger diameter than the scrowed
portion which enters into the shell so as to prevent any possibility of the fuze case
being driven into the shell by the firing of the gun.
The rotation of the plunger with the shell is accomplished by a wire in the
plunger running in a hole in the head of the fuze or by a slot in the side of tho
fuze case and a projection or stud in the side of the plunger running in the slot.
In the base of the soft metal are left, in casting or in manufacturing, grooves or
hollow spaces to allow for the displacement of the metal so as to provide against its
expanding the exterior tube and thus preventing the movement of the plunger
when the primer has to be fired.
The application of this fuze to the base of a shrapnell shell simplifies and
cheapens the construction by avoiding the fuze passage from the nose of the shell to
the powder chamber and is one of the essential features of the Invention. The fuze
is simply screwed into the base of the shell and communicates directly with the
powder.
The space usually occupied by the communicating tube is therefore occupied hy
balls or segments.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Benjamin Berkley Hotchkiss in the Great Seal Patent Offico on
the 14th April 1880.
rice versa.
BENJAMIN BERKLEY HOTCHKISS of 38 Southampton Buildings Chancery Lano
London. "IMPROVMENETS IN SHRAPNELL SHELLS AND THE PERCUSSION FUZES
FOR THEM SUCH PERCUSSION FUZES BEING ALSO APPLICABLE TO OTHER SHELLS."
The object of the Invention is to simplify the construction of the shrapnell shell
by obviating the necessity of using tho fuzo passage from the nose of the shell to
the powder charge in the base by employing a percussion fuze of the kind described
in the base of the shell and also to produce a fuze for this kind of shell or others
which is absolutely effective completely safe during the transport of the projectiles
to which the fuzes are attached and which does not require any manipulation to
arm the fuze before the discharge of the projectile. For this purpose one of the
principal parts of the fuze, that is, either the firing pin, or the primer or priming
is carried on a comparatively heavy body which under certain circumstances is
capaple of a short movement or displacement in its case on a line parallel to the
axis of the projectile. This heavy body or plunger in consequence of its inertia
effects first the arming of the fuze at the moment of the discharge of the gun, and
afterwards the ignition of the primer, when the projectile is suddenly arrested by
resistance to its flight, whilst before the discharge, the plunger is firmly held in such
position as to prevent the accidental contact of the firing pin with the primer or
This plunger is composed of three parts, first a body of soft metal,
such as lead, second a case or envelope of hard metal, for instance brass, in which
the soft motal is partly enclosed and third a central pin of hard metal the front
end of which either terminates in a point, acting as the firing pin or carries the
primer. The rear and of this central pin projects beyond the bottom of the plunger,
whilst its front end is sunk a little in the face of the plunger; the entire length
of this compound part is so calculated, that when it is inserted in the fuze case and
when the screw cap is in place, the firing pin point cannot touch the primor and
that it cannot displace itself without a considerable shock. The surface of the
central pin is roughened by indentations prejections or screw threads so as to afford
a sufficient hold to the surrounding lead to prevent any accidental displacement.
At the moment of the discharge of the gun, the plunger, in consequence of its
inertia, slides back on its central firing pin until it strikes against the bottom of the
fuze caso, the point itself then standing above the enclosing soft metal ready to be
projected on to the fulminate or primer. The force of this shock is so great that
the lead again closes tightly around the pin and when the projectile then strikes
against any obstacle the inertia momentum of the plunger is-overcome and the plunger
acting in the opposite direction, drives this compound part, that is, causes it to
continue its motion so that the enclosing case the soft metal and the firing pin are driven
forward, producing thus the ignition of the primer, the flame of which causes the
ignition of the powder charge in the projectile. Besides the facilities already
mentioned which are derived from the use of lead or other soft metal for forming the
main body of the plunger, the advantage is obtained that the latter is not liable to
rebound, whereby a premature explosion might be produced.
In certain cases the percussion, which causes the explosion is effected with more
certainty by mounting the fuze at the butt end of the projectile. For instance when
a projectile strikes laterally instead of with its point, a fuze arranged in the front
or nose end of the projectile is liable to fail from the crushing of the head of the
fuze case when the shell strikes obliquely thus preventing the action of the
plunger whilst a butt fuze, even under such circumstances, detonates almost
invariably; and besides, such arrangement renders the construction of the projectile
simpler and less costly. Therefore this new fuze is especially adapted for serving
as a butt fuze.

page_text: the projectile the interior compound part being shown in the position in which it
is relatively immoveable, that is, as it is inserted in the fuze case which position
it occupies until the moment of the discharge of the projectile.
Figure 2 is an inverted plan of the same in section on the line A B Figure 1.
Figure 3 is a plan of the upper part of the same fuze.
Figure 4 is an elevation in section of the same, the interior compound part being
shown in the position which it occupies after the discharge of the gun and during
the unobstructed flight of the projectile.
Figure 5 is a plan of the base of this same fuzo.
Figure 6 is an elevation in section sbowing a modification of this fuze.
Figure
Figure
7 is a plan of the upper part of this modification.
8 is an elevation in section of a second modification of this fuze.
Figure 9 is an elevation in section of this fuzo constructed so as to be applied on
the nose end of the projectile, the interior compound part being shown in the
position before tho discharge.
Figure 10 a plan of the same in section on the line CD Figure 9.
Figure 11 is another elevation of this latter fuze showing the position of the
interior compound part after the discharge of the gun and during the unobstructed
flight of the projectile.
Figure 12 is a plan of the same.
Figure 13 is an elevation in section showing a modification of this latter fuze.
Figure 14 is a longitudinal elevation of a shrapnell projectile provided at its butt
end with this new fuzo and,
Figure 15 is a similar view, the projectile itself being of different construction.
In these Figures 14 and 15 is shown the improvements on the ordinary shrapnell
where the fuze passage from the nose and the shell is done away with and tho
space is occupied by bullets. In Figure 15 the ordinary division plate of the
common shrapnell is shown but in Figure 14 a still further improvement to
simplify and cheapen the shell is shown; the ordinary division plate being cast
with the body of the shell; an annular groove 18 showing the weak point at which
the shell bursting the plate breaks out and acts the same as the ordinary division
plate whilst in the opposite direction to it it supports the bullets as effectually as a
the ordinary plate. In the centre of the plate a hole can be left for assisting in
the casting and coring, the hole can be filled with one of the balls or any other
means may be employed.
Referring to Figures 1, 2, 3, 4 and 5, 1 is the fuzo case of cylindrical form, open
on one end and having an external thread cut on it, by means of which it is
attached to the butt end of the projectile.
The head 2 of this fuze is of a diameter somewhat larger than the cylindrical part 1
to prevent the fuze from being forced inward into the projectile at the moment of
the discharge. This head is formed with flat sides Figure 5 on which the jaws of a
screw wrench may be applied to screw the fuze in place. A thin projecting lip 34
formed around the base of the head 2 serves as a gas check by pressing tightly
against the metal of the projectile when the fuze is screwed in place and at the
moment of the discharge. The front part of tho caso 1 is closed by moans of a
screw plug 4 in which is arranged the primer 5 held in place by means of a
smaller screw plug 6. One or more small holes drilled drilled in the screw plug 6
serve to let the flame of the primer pass into the powder chamber of the projectile.
7 is a pin, formed with a firing point 8 of steel or other appropriate metal. It
is enclosed in the plunger of lead or other soft metal 9, the latter being surrounded
by a jacket of brass or other suitable metal 10, which latter serves to provent the
lateral expansion of the lead at the moment of the discharge. In order to properly
hold together these parts in their relative positions as desired, the jacket 10 is
drawn in at its ends, thus holding the soft metal 9 firmly in place and the pin 7

page_text: is roughened either by cutting a thread on it or by forming other indentations or
ridges on its surface in which the surrounding soft metal enters. The firing point
8 of the pin 7 is slightly sunk below the surface of the plunger, whilst its roar
extremity projects beyond the rear end of the latter and the total length of this
compound part is exactly the same as that of the space in the fuze case in which it
is arranged, when the cap 4 is screwed home. The fulminato is enclosed in an
ordinary case covered with a piece of brass 13.
In order to prevent the plunger thus composed from turning in the fuze caso, I
arrange on the upper end of the casing 10 a projection 11 which engages with a
corresponding groove formed in the fuze case 1. This groove is only a little longer
than the rim of the plunger so that, if the latter should, by negligence be inserted
upside down, the screw cap 4 can not be screwed home. It is thus made impossiblo
to put the parts together in a manner which would prevent the effective working
of the fuze. The same result is obtained by means of a pin 11 cast into the metal 9,
the projecting end of which enters into a bole formed for the purpose in the head 2,
see Figure 8.
On the discharge of the projectile, the plunger 7, in consequence of its inertia
which tonds to provent it from following the motion of the projectile, slides down
on the firing pin 7 until it strikes against the bottom of the fuze case so that tho
rear extremities of the plunger and of the pin 7 come on a level with each other,
the force of this percussion is so great that the lead again closes firmly around the
pin and in order to prevent the lateral expansion of the lead, which might cause
the bursting of the envelope 10, there are formed a number of holes 12 in the
plunger, see Figures 1, 2, 4, 6, 8, 9 and 10, or, what is preferable a single circular
cavity, as shown at 12 Figure 13. Under these conditions tho firing point 8
projects beyond the face of the plunger 9 that is to say, the fuze is now armed.
When the projectile is now suddenly arrested in its course by striking against any
obstacle, the plunger is thrown violently forward and the firing point strikes
against the primer 5 causing the inflammation of the same and the fire thus
produced passes through the holes in the screw plug 6 and ignites the powder
charge of the projectile whereby the latter is caused to burst.
Figures 6 and 7 show a butt fuze constructed on the same principles with the
only modification that here the primer is caused to strike on the firing point; for
this purpose the latter, 8, is formed on the screw plug 4 which is also provided with
holes to let the fire pass into the powder chamber of the projectile and the primer
is mounted on the front end of the pin 7.
Figure 8 shows another modification of the primer according to which this latter,
instead of being composed of a small casing filled with detonating material and
held in place by a screw plug 6 as shown in Figures 1 to 5, is replaced by a small
quantity of detonating material compressed directly into the scrow plug 4.
Figures 9 to 13 show the adaptation of this class of fuzes on the front end of the
projectiles. The modifications necessitatod by this use are very slight and consist
principally in providing a passage for the flame of the primer to the charge of the
projectile. This passage is preferably formed by a hole drilled longitudinally into
the central pin 7 whether the latter is employed as primer carrier as shown in
Figures 9, 10 and 11, or whether it acts as a percussion pin as in Figure 13. The
head 2 of the fuze is of course arranged on the front end, which is formed open for the
insertion of the plunger and its accessories and closed afterwards by a screw plug 4
carrying either the primer or the firing point. The other extremity of the case is
closed and in the bottom are drilled one or more small holes for the passage of the
flame.
Figures 14 and 15 show the adaptation of this fuze on the butt end of shrapnell
shells, and serve to indicate certain advantages, which result from this adaptation.
These advantages consist, first, in the suppression of the central powder canal
serving to direct the fire of the primer on the nose end to the powdor charge at the
other end, whereby the construction is simplified and the cost diminishod and at
the same time a larger space is gained for the bullet filling of the projectile. In

page_text: Figure 14 the projectile is cast in one single piece with an opening in its front end,
for the introduction of the charge, which is closed afterwards by a screw plug 15,
and in Figure 15 the projectile is cast in two pieces 16 and 17, which are screwed
together after being charged.
Having thus described the nature of my Invention as well as the best means
known to me to carry the same into practice, I claim and desire to secure by
Letters Patent ;-
1. In a percussion fuze, a plunger formed of three parts an external case of hard
metal a central pin of hard metal, and a soft metal placed between the two
substantially as described and for the purposes set forth.
2. The central pin of the plunger having a roughened surface in combination
with the soft metal surrounding the same substantially as specified and for the
purposes set forth.
3. The means 11 on the plunger-9 combined with a suitable hole in the head of
the fuze ease to prevent rotation with reference to the run of the planger
substantially as shown and described in Figure 8.
42. The relieving cavities 12 formed in the base of the plunger, substantially as
described and for the purposes set forth.
5 3. The head 2 of a butt fuze formed of larger diameter than the hole in the shell,
so as to give the necessary strength in combination with the projecting lip 3
which serves to form a gas check.
4. The shrapnell shell substantially as constructed and shown in Figuro 15.
75. The shrapnell shell as constructed and shown in Figure 14 with the division
plate cast in it solid and with the annular groove or weak breaking point
substantially as described.
In witness whereof I the said Benjamin Berkley Hotchkiss have hereunto
set my hand and seal this Fourteenth day of April in the year of our Lord
One thousand eight hundred and eighty.
Witnesses
T. H. FAVARGER,
KOENNER.
B. B. HOTCHKISS. (L.S.)

page_text: LETTERS PATENT to Benjamin Berkley Hotchkiss, of 38, Southampton
Buildings, Chancery Lane, London, for the Invention of "IMPROVEMENTS IN
SHRAPNELL SHELLS AND THE PERCUSSION FUZES FOR THEM, SUCH PERCUSSION
FUZES BEING ALSO APPLICABLE TO OTHER SHELLS."
PROVISIONAL SPECIFICATION left by the said Benjamin Berkley Hotchkiss
at the Office of the Commissioners of Patents on the 15th October 1879.
BENJAMIN BERKLEY HOTCKISS, of 38, Southampton Buildings, Chancery Lane
London. "IMPROVEMENTS IN SHRAPNELL SHELLS AND THE PERCUSSION FUZES
FOR THEM, SUCH PERCUSSION FUZES BEING ALSO APPLICABLE TO OTHER SHELLS."
The object of this Invention is to simplify the construction of the shrapnell shell
by obviating the necessity of using the fuze passage from the nose of the shell to
the powder charge in the base by employing a percussion fuze of the kind described
in the base of the shell, and also to produce a fuze for this kind of shell or others
which is absolutely effective, completely safe during the transport of the projectiles
to which the fuzes are, attached, and which does not require any manipulation
to arm the fuze before the discharge of the projectile. For this purpose one of the
principal parts of the fuze, that is, either the firing pin, or the primer, or priming, is
carried on a comparatively heavy body, which under certain circumstances is capable
of a short movement or displacement in its case on a line parallel to the axis of the
projectile. This heavy body or plunger in consequence of its inertia, effects first
the arming of the fuze at the moment of the discharge of the gun, and afterward
the ignition of the primer when the projectile is suddenly arrested by resistance to
its flight, whilst before the discharge the plunger is firmly held in such position as
to prevent the accidental contact of the firing pin with the primer or vice versu.
This plunger is composed of three parts; first, a body of soft metal, such
as lead; second, a case or envelope of hard metal, for instance, brass, in which the
soft metal is partly enclosed; and third, a central pin of hard metal, the front end
of which either terminates in a point acting as the firing pin or carries the primer.
The rear end of this central pin projects beyond the bottom of the plunger, whilst
its front end is sunk a little in the face of the plunger; the entire length of this
compound part is so calculated that when it is inserted in the fuze case, and when
[Pins 37

page_text: the screw cap is in place the firing pin point cannot touch the primer, and that it
cannot displace itself without a considerable shock. The surface of the central pin
is roughened by indentations, projections, or screw thread, so as to afford a
sufficient hold to the surrounding lead to prevent any accidental displacement. At
the moment of the discharge of the gun the plunger, in consequence of its inertia,
slides back on its central firing pin until it strikes against the bottom of the fuze
case, the point itself then standing above the enclosing soft metal ready to be
projected on to the fulminate or primer. The force of this shock is so great that
the lead again closes tightly around the pin, and when the projectile then strikes
against any obstacle the inertia of the plunger is overcome, and the plunger acting
in the opposite direction drives this compound part, that is, the enclosing case, the
soft metal, and the firing pin forward, producing thus the ignition of the primer, the
flame of which causes the ignition of the powder charge in the projectile. Besides
the facilities already mentioned, which are derived from the use of lead or other
soft metal for forming the main body of the plunger, the advantage is obtained that
the latter is not liable to rebound, whereby a premature explosion might be
produced.
In certain cases the percussion which causes the explosion is effected with more
certainty by mounting the fuze at the butt end of the projectile; for instance, when
a projectile strikes laterally instead of with its point a fuze arranged in the front
or nose end of the projectile is liable to fail, whilst a butt fuze even under such
circumstances detonates almost invariably; and besides, such arrangement renders
the construction of the projectile simpler and less costly. Therefore this new fuze
is specially adapted for serving as a butt fuze.
The parts thus described are enclosed in a fuze case of bronze or other metal
constructed to screw into the shell to be fired, which is provided with a projecting
flange acting as a gas check, and which is a part of the fuze case.
The head of the fuze case is constructed of a larger diameter than the screwed
portion which enters into the shell, so as to prevent any possibility of the fuze case
being driven into the shell by the firing of the gun.
The rotation of the plunger with the shell is accomplished by a wire in the
plunger running in a hole in the head of the fuze or by a slot in the side of the
fuze case and a projection or stud in the side of the plunger running in the slot.
In the base of the soft metal are left, in casting or in manufacturing, grooves or
hollow spaces to allow for the displacement of the metal so as to provide against its
expanding the interior tube, and thus preventing the movement of the plunger
when the primer has to be fired.
The application of this fuze to the base of a shrapnell shell simplifies and
cheapens the construction by avoiding the fuze passage from the nose of the shell to
the powder chamber, and is one of the essential features of the Invention. The fuze
is simply screwed into the base of the shell, and communicates directly with the
powder.
The space usually occupied by the communicating tube is therefore occupied by
balls or segments.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Benjamin Berkley Hotchkiss in the Great Seal Patent Office on
the 14th April 1880.
BENJAMIN BERKLEY HOTCHKISS, of 38, Southampton Buildings, Chancery Lane,
London. "IMPROVEMENTS IN SHRAPNELL SHELLS AND THE PERCUSSION FUZES
FOR THEM, SUCH PERCUSSION FUZES BEING ALSO APPLICABLE TO OTHER SHELLS."
The object of this Invention is to simplify the construction of the shrapnell shell
by obviating the necessity of using the fuze passage from the nose of the shell to
the powder churge in the base by employing a percussion fuze of the kind described
in the base of the shell, and also to produce a fuze for this kind of shell or others
which is absolutely effective, completely safe during the transport of the projectiles
to which the fuzes are attached, and which does not require any manipulation to
arm the fuze before the discharge of the projectile. For this purpose one of the
principal parts of the fuze, that is, either the firing pin, or the primer, or priming,
is carried on a comparatively heavy body, which, under certain circumstances is
capable of a short movement or displacement in its case on a line parallel to the
axis of the projectile. This heavy body or plunger in consequence of its inertia
effects first the arming of the fuze at the moment of the discharge of the gun, and
afterwards the ignition of the primer when the projectile is suddenly arrested by
resistance to its flight, whilst before the discharge the plunger is firmly held in such
position as to prevent the accidental contact of the firing pin with the primer or
vice versa. This plunger is composed of three parts; first, a body of soft metal,
such as lead; second, a case or envelope of hard metal, for instance, brass, in which
the soft metal is partly enclosed; and third, a central pin of hard metal, the front
end of which either terminates in a point acting as the firing pin or carries th
primer. The rear end of this central pin projects beyond the bottom of the plunger,
whilst its front end is sunk a little in the face of the plunger; the entire length of
this compound part is so calculated that when it is inserted in the fuze case, and
when the screw cap is in place the firing pin point cannot touch the primer, and
that it cannot displace itself without a considerable shock. The surface of the
central pin is roughened by indentations, projections, or screw threads, so as to afford
a sufficient hold to the surrounding lead to prevent any accidental displacement.
At the moment of the discharge of the gun the plunger, in consequence of its
inertia, slides back on its central firing pin until it strikes against the bottom of the
fuze case, the point itself then standing above the enclosing soft metal ready to be
projected on to the fulminate or primer. The force of this shock is so great that
the lead again closes tightly around the pin, and when the projectile then strikes
against any obstacle the inertia of the plunger is overcome, and the plunger acting
in the opposite direction drives this compound part, that is, the enclosing case, the
soft metal, and the firing pin forward, producing thus the ignition of the primer,
the flame of which causes the ignition of the powder charge in the projectile. Besides
the facilities already mentioned, which are derived from the use of lead or other
soft metal for forming the main body of the plunger, the advantage is obtained that
the latter is not liable to rebound, whereby a premature explosion might be
produced.
In certain cases the percussion which causes the explosion is effected with more
certainty by mounting the fuze at the butt end of the projectile; for instance, when
a projectile strikes laterally instead of with its point, a fuze arranged in the front
or nose end of the projectile is liable to fail from the crushing of the head of the
fuze case, when the shell strikes obliquely, thus preventing the action of the
plunger, whilst a butt fuze, even under such circumstances, detonates almost
invariably; and besides, such arrangement renders the construction of the projectile
simpler and less costly. Therefore, this new fuze is especially adapted for serving
as a butt fuze.

page_text: In order to make the Invention clearly understood I will describe it in detail,
conjointly with the 15 Figures of the accompanying Drawings, of which-
Figure 1 is an elevation in section of a fuze to be mounted in the butt end of
the projectile, the interior compound part being shown in the position in which it
is relatively immoveable, that is, as it is inserted in the fuze case, which position
it occupies until the moment of the discharge of the projectile.
Figure 2 is an inverted plan of the same in section on the line A, B, Figure 1.
Figure 3 is a plan of the upper part of the same fuze.
Figure 4 is an elevation in section of the same, the interior compound part being
shown in the position which it occupies after the discharge of the gun and during
the unobstructed flight of the projectile.
Figure 5 is a plan of the base of this same fuse.
Figure 6 is an elevation in section showing a modification of this fuze.
Figure 7 is a plan of the upper part of this modification.
Figure 8 is an elevation in section of a second modification of this fuze.
Figure 9 is an elevation in section of this fuze constructed so as to be applied on
the nose end of the projectile, the interior compound part being shown in the
position before the discharge.
Figure 10, a plan of the same in section on the line C, D, Figure 9.
1
Figure 11 is another elevation of this latter fuze, showing the position of the i
interior compound part after the discharge of the gun and during the unobstructed
flight of the projectile.
Figure 12 is a plan of the same.
Figure 13 is an elevation in section, showing a modification of this latter fuze.
Figure 14 is a longitudinal elevation of a shrapnell projectile provided at its butt
end with this new fuze, and
Figure 15 is a similar view, the projectile itself being of different construction.
In these Figures 14 and 15 is shewn the improvements on the ordinary shrapnell
where the fuze passage from the nose and the shell is done away with, and the
space is occupied by bullets. In Figure 15 the ordinary division plate of the
common shrapnell is shown; but in Figure 14 a still further improvement to
simplify and cheapen the shell is shown, the ordinary division plate being cast
with the body of the shell; an annular groove 18 showing the weak point at which
the shell bursting the plate breaks out and acts the same as the ordinary division
plate, whilst in the opposite direction to it, it supports the bullets as effectually as
the ordinary plate. In the centre of the plate a hole can be left for assisting in
the casting and coring; the hole can be filled with one of the balls or any other
means may be employed.
Referring to Figures 1, 2, 3, 4, and 5, 1 is the fuze case of cylindrical form, open
on one end, and having an external thread cut on it, by means of which it is
attached to the butt end of the projectile.
The head 2 of this fuze is of a diameter somewhat larger than the cylindrical part 1
to prevent the fuze from being forced inward into the projectile at the moment of
the discharge. This head is formed with flat sides, Figure 5, on which the jaws of a
screw wrench may be applied to screw the fuze in place. A thin projecting lip 3
formed around the base of the head 2 serves as a gas check by pressing tightly
against the metal of the projectile when the fuze is screwed in place and at the
moment of the discharge. The front part of the case 1 is closed by means of a
screw plug 4, in which is arranged the primer 5, held in place by means of a
smaller screw plug 6. One or more small holes drilled drilled in the screw plug 6
serve to let the flame of the primer pass into the powder chamber of the projectile.
7 is a pin formed with a firing point 8 of steel or other appropriate metal. It
is enclosed in the plunger of lead or other soft metal 9, the latter being surrounded
by a jacket of brass or other suitable metal 10, which latter serves to prevent the
lateral expansion of the lead at the moment of the discharge. In order to properly
hold together these parts in their relative positions as desired, the jacket 10 is
drawn in at its ends, thus holding the soft metal 9 firmly in place, and the pin 7

page_text: is roughened either by cutting a thread on it or by forming other indentations or
ridges on its surface, in which the surrounding soft metal enters. The firing point
8 of the pin 7 is slightly sunk below the surface of the plunger, whilst its rear
extremity projects beyond the rear end of the latter, and the total length of this
compound part is exactly the same as that of the space in the fuze case in which it
is arranged when the cap 4 is screwed home. The fulminate is enclosed in an
ordinary case covered with a piece of brass 13.
In order to prevent the plunger thus composed from turning in the fuze case, I
arrange on the upper end of the casing 10 a projection 11, which engages with a
corresponding groove formed in the fuze case 1. This groove is only a little longer
than the rim of the plunger, so that if the latter should by negligence be inserted
upside down, the screw cap 4 can not be screwed home. It is thus made impossible
to put the parts together in a manner which would prevent the effective working
of the fuze. The same result is obtained by means of a pin 11 cast into the metal 9,
the projecting end of which enters into a hole formed for the purpose in the head 2,
see Figure 8.
On the discharge of the projectile the plunger q, in consequence of its inertia,
which tends to prevent it from following the motion of the projectile, slides down
on the firing pin 7 until it strikes against the bottom of the fuze case, so that the
rear extremities of the plunger and of the pin 7 come on a level with each other;
the force of this percussion is so great that the lead again closes firmly around the
pin, and in order to prevent the lateral expansion of the lead, which might cause
the bursting of the envelope 10, there are formed a number of holes 12 in the
plunger, see Figures 1, 2, 4, 6, 8, 9, and 10, or what is preferable a single circular
cavity, as shown at 12, Figure 13. Under these conditions the firing point 8
projects beyond the face of the plunger 9, that is to say, the fuze is now armed.
When the projectile is now suddenly arrested in its course by striking against any
obstacle the plunger is thrown violently forward, and the firing point strikes
against the primer 5, causing the inflammation of the same, and the fire thus
produced passes through the holes in the screw plug 6 and ignites the powder
charge of the projectile, whereby the latter is caused to burst.
Figures 6 and 7 show a butt fuze constructed on the same principles, with the
only modification that here the primer is caused to strike on the firing point; for
this purpose the latter 8 is formed on the screw plug 4, which is also provided with
holes to let the fire pass into the powder chamber of the projectile, and the primer
is mounted on the front end of the pin 7.
Figure 8 shows another modification of the primer according to which this latter,
instead of being composed of a small casing filled with detonating material, and
held in place by a screw plug 6, as shown in Figures 1 to 5, is replaced by a small
quantity of detonating material compressed directly into the screw plug 4.
Figures 9 to 13 show the adaptation of this class of fuzes on the front end of the
projectiles. The modifications necessitated by this use are very slight, and consist
principally in providing a passage for the flame of the primer to the charge of the
projectile. This passage is preferably formed by a hole drilled longitudinally into
the central pin 7, whether the latter is employed as primer carrier, as shown in
Figures 9, 10, and 11, or whether it acts as a percussion pin, as in Figure 13. The
head 2 of the fuze is of course arranged on the front end, which is formed open for the
insertion of the plunger and its accessories, and closed afterwards by a screw plug 4,
carrying either the primer or the firing point. The other extremity of the case is
closed, and in the bottom are drilled one or more small holes for the passage of the
flame.
Figures 14 and 15 show the adaptation of this fuze on the butt end of shrapnell
shells, and serve to indicate certain advantages which result from this adaptation.
These advantages consist, first, in the suppression of the central powder canal,
serving to direct the fire of the primer on the nose end to the powder charge at the
other end, whereby the construction is simplified and the cost diminished, and at
the same time a larger space is gained for the bullet filling of the projectile. In

page_text: Figure 14 the projectile is cast in one single piece, with an opening in its front end
for the introduction of the charge, which is closed afterwards by a screw plug 15,
and in Figure 15 the projectile is cast in two pieces 16 and 17, which are screwed
together after being charged.
Having thus described the nature of my Invention, as well as the best means
known to me to carry the same into practice, I claim and desire to secure by
Letters Patent,-
1. In a percussion fuze a plunger formed of three parts, an external case of hard
metal, a central pin of hard metal, and a soft metal placed between the two,
substantially as described and for the purposes set forth.
2. The central pin of the plunger having a roughened surface in combination
with the soft metal surrounding the same, substantially as specified, and for the
purposes set forth.
3. The means 11 on the plunger 9 combined with a suitable hole in the head of
the fuze case to prevent rotation with reference to the run of the plunger,
substantially as shown and described in Figure 8.
4. The relieving cavities 12 formed in the base of the plunger, substantially as
described and for the purposes set forth.
5. The head 2 of a butt fuze formed of larger diameter than the hole in the shell,
so as to give the necessary strength in combination with the projecting lip 3,
which serves to form a gas check.
6. The shrapnell shell, substantially as constructed and shown in Figure 15.
7. The shrapnell shell, as constructed and shown in Figure 14, with the division
plate cast in it solid, and with the annular groove or weak breaking point,
substantially as described.
In witness whereof, I, the said Benjamin Berkley Hotchkiss, have hereunto
set my hand and seal, this Fourteenth day of April, in the year of our Lord
One thousand eight hundred and eighty.
Witnesses,
T. H. FAVARGER,
KOENNER.
B. B. HOTCHKISS. (L.S.)