Improvements in and Mode of Firing Explosive and other Projectiles and in Cartridges for the same.
Year: 1890

page_text: COMPLETE SPECIFICATION.
Improvements in and Mode of Firing Explosive and other Projectiles
and in Cartridges for the same.
I, RANDALL BISBEE, of No. 717, Fifth Avenue, New York, in the County and State
of New York, United States of America, Manufacturer, 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 :-
The essential object of my invention is to provide improvements in the con-
struction of dynamite or other high explosive shells, also improvements in
cartridges for, and mode of firing such shells more effectually and safely than
as they are made and fired at the present time, also improvements in spiral
vanes for rotating the shell, and also improvements in gas checks for the shell,
part of which improvements are also applicable for firing solid shot. The
essential improvement in the mode of firing consists in first applying a starting
force of moderate power and comparatively slow action to overcome the inertia
of the projectile with the minimum amount of shock through the prior explosion
of a portion of a differential cartridge, and thereafter following up the projectile
already under way with one or more greater and quicker increments of force
of said cartridge applied after the movement of the projectile begins, but before
its escape from the gun whereby the effect on the projectile is greater and the
stress on the gun is less than when the full power of the cartridge is delivered
at once, and what is more important, it is possible as I have found in practice
to fire dynamite and other high explosive shells safely with powerful explosive
cartridges from ordinary guns, but for best effects the length should be somewhat
greater than ordinary, and another advantage is that quicker powder and a
greater quantity can be used in the following portion or portions of the cartridge
than can be used in the whole charge when the whole is exploded at once.
My improvements in mode of firing shells also comprise the employment of a
cushioning sabot of cork behind the shell, the advantage of which as compared with
other means of cushioning the same will, together with the rest of my improvements
be hereinafter fully described reference being made to the accompanying drawings
in which :-
Fig. 1 is a sectional elevation of a shell substantially as I construct it, also a
section of a cartridge such as I provide for firing the shell, and also of a portion of
a gun in the bore of which the shell and cartridge are placed for firing.
Fig. 2 is a side elevation of a rear portion of my improved shell showing a novel
application of spiral wings or vanes for effecting rotation of the shell in its flight, it
also shows my improved gas checks in section.
Fig. 3 is an elevation of the rear end of the shell more fully illustrating the wings
or vanes.
Fig. 4 is an end elevation of one of the structural forms in which I prepare the
dynamite charge.
Fig. 5 is an edge view of the prepared sheet for the dynamite charge previous to
being rolled up into the form of Fig. 4.
Fig. 6 is a transverse section of a tray composing part of another structural form
in which the shell charge may be made in whole or in part as shown in Fig. 1.
Fig. 7 is a plan view of part of said tray, these two figures are represented on an
enlarged scale.
Fig. 8 is partly a plan view of the cartridge of Fig. 1 for firing the explosive
shell from the gun and partly a horizontal section of the case on line z z, Fig. 1.
Fig. 9 is a horizontal section of the cartridge on line y y, Fig. 1.
Fig. 10 is a vertical section of the cartridge and side view of part of a solid shot
illustrating a modified form of the cartridge for such shot.
Prine 71

page_text: Fig. 1 is a section of the cartridge showing a modified form of differential
charge.
For the construction of the shell I prefer to provide a base section a, of cast,
rolled or stamped metal and having a suitable interior chamber with one or two
hollow cylinders of preferably seamless tubing b, shrunk on the base so as to make
a very strong case not liable to fracture by the explosion of the firing cartridge and
being gas tight for effectually preventing the access of the gas from the firing charge
to the contents of the shell.
These cylinders b, are applied to the base so that the outer one terminates a suit-
able distance above or in advance of the rear end to provide the annular recess c, the
depth of the thickness of the outer cylinder along the rear of the shell, and of suitable
length for the application of the spiral vanes or wings d, for imparting rotation to
the shell in its flight, which vanes or wings I propose to make of thin springy sheet
metal preferably in two leaves secured at the outer edge, and to fasten them at the
forward end and partly along the edge e, if preferred, by solder or other approved
means; they may be attached to a band a', secured in a circumferential groove in
the surface of the shell or by studs, inserted behind the band said wings having
a breadth and outward spiral projection normally much wider than the depth of the
recess c, but greater in longitudinal dimensions than in breadth and adapted for
compression within the limits of said space for enabling the shell to be inserted in
the gun, and capable of expanding instantly on issuing therefrom to take the required
effect on the air for rotating the shell. These wings are alike applicable to solid
shot, they will effect rotation of shot or shell fired from smooth bore guns completely
avoiding the resistance caused by rigid spiral ribs in the rifle grooves of the bore as
such ribs have been used.
At the forward ends of these cylinders one extends a suitable distance beyond the
other to form the off-set for reception of the correspondingly recessed, rear portion
of the cap or head, of the shell which, together with the cylinder will be suitably
threaded for screwing together as the most preferable way of fastening them but
any other approved mode of fastening them may be employed if desired.
In the preparation of the charge of dynamite for the shell I take a sheet of stiff
corrugated paper g, as wide transversely to the corrugations as the desired length
of this portion of the charge, and having saturated it with nitro-glycerine and spread
on a layer of dynamite powder or other approved explosive substance, roll it up
lengthwise of the corrugations into the coil or roll h, Figs. 1 and 4, of suitable size
to nearly fill the chamber of the shell diametrically, then I coat the roll with varnish
or any other approved substance to provide an impervious protecting skin which
prevents the escape of the powder from the interstices of the ends of the roll and
cements the layers and preserves the form of the roll, and also prevents evaporation
of the saturating solution, and finally I insert the roll in a hollow cylindrical case
of strong paper or thin sheet metal as 2 which I also varnish for closing the pores
or joints and for protection.
It will be seen that whilst this structure provides a most powerful explosive, it is
at the same time well adapted for effectually preventing any possibility of the
crushing and grinding of the parts to which such charges are subject by their
inertia when discharged from the gun when not sufficiently rigid to withstand the
same which, in some instances has resulted in exploding the shell in the gun by the
friction of such action.
Whilst the charge of this structure is highly efficient of itself as I have
practically demonstrated and may be used alone with excellent results, I have found
it advantageous also, to construct a portion of the charge in the form of thin layers
of dynamite, gun cotton or other explosive as i, placed in trays, one upon another,
said trays having substantial rims that will protect the layers from being crushed
by the force of inertia of firing, and preferably having intermediate rims, to
support the bottoms of the superimposed trays from the same effects, the trays may
be reinforced at the middle of the bottom with an extra thickness 3 if desired.
When I use this form of the explosive charge together with the roll h, I will

page_text: preferably locate it in rear of said roll with a suitable diaphragm m, or wood, straw-
board or other approved material between them.
Between the explosive charge and the botton of the shell I provide a cushion of
thin layers of cork m', preferably with interposed layers n, of curled hair or it may
be shavings of cork, the said layers or shavings of cork being from a thirty-second
to a sixteenth of an inch thick but not necessarily limited to these dimensions as it
is obvious that they may be varied to some extent with good results.
I also cushion the front end of the charge in like manner, first however filling
the slight space between the explosive charge, and the interior of the shell with
quick burning powder or other explosive substance o, not so quick as dynamite,
which being fired by the detonating cap p, above through the back thrust of the
striking head g, or other means as may be preferred, and exploding slightly in
advance of the charge, of much quicker action, will, by its compression of said
charge and the consequent greater reaction due to such compression result in much
more powerful explosion than the charge 4, fired alone, or both fired together are
capable of. It is as though the charge were rammed in hard as it is possible to
ram powder which it is well known effects more powerful explosion than when fired
in a slack condition, this is alike advantageous with any form, structure or
quality of the interior charge h, provided said interior charge is quicker in
action.
The head 7, is carried on rods s, fitted in holes of the cap of the shell so as to
project beyond the cap a suitable distance to strike the object fired at in advance
of the head and be thrust back with sufficient force to explode the fulminate
or detonator, but I make no claim to this mode of firing, it having been used
before. I propose to avail myself of any other means of firing that may be
found useful.
The mode of firing the shell from the gun which forms a part of my invention
consists in the employment of a cork cushioning sabot comprising a suitable number
of layers of cork t, between the shell and the cartridge for gently starting the shell,
and it includes, when more gentle action is required, my improved cartridge for
first applying a starting force of moderate power and comparatively slow action to
overcome the inertia of the shell with the minimum amount of shock through the
prior explosion of a primary graduated portion of the explosive element of the
cartridge, and thereafter following up the projectile under way with one or more
greater and quicker increments of force of one or more other portions of the
cartridge exploded after the movement of the projectile begins but before its escape
from the gun whereby the effect on the projectile is greater and the stress on the
gun is less than when the full power of the cartridge is delivered at once, which
improved cartridge is also applicable for solid shot.
In any approved metallic or other case a', I arrange the charge of powder in two
or more sections as b¹, c', or b', c', and d¹, together with a thin layer of fine igniting
powder e', placed on the upper surface of section c¹, said section cl, being a small
part of the whole charge and composed of slow burning powder having sufficient
power to overcome the inertia of the projectile with a gentle impulse and set it in
motion at moderate speed, the said section of the charge being fired sufficiently in
advance of the rest to effect movement of the projectile before it receives the
impulse of the next following section of the cartridge which may be section b¹, or
an intermediate section d', of larger quantity and much greater power to be fired
so as to take effect directly after the projectile has been started by the first section.
If the intermediate charge d', is used it will be graduated as to quickness of burning
intermediately to the burning rates of the other two sections but the section ', will
be of high grade as to power and quickness of burning action.
For the section c', it will be preferred to use a disk of compressed powder placed
in a cup, of thin sheet metal, or other suitable material closely fitting the shell
for effecting the substantial separation of it from the next section but having small
openings through it as g', preferably in the central portion, through which the next
section may be ignited at a later period the first being fired at the top say by an

page_text: Tectric spark from the wire ', but any other means of hiring may of course be
employed.
When the intermediate section d', is employed it will probably be preferred to
have it consist of small compressed hexagonal grains as shown in Figs. 1 and 9, and
suitably placed for sustaining the reaction of the explosion of section e', without
crushing, but it may of course be provided in other form as a compressed disk or in
radial wedges such as will pack suitably. The graduation of section c', as to its
quickness may be effected by its density of compression and the degree of closeness
of the packing of the grains or parts. The proportionate rate of burning of this
disk which is so confined that it can only burn on the top is approximately three
times slower than if in the condition of section d', it will be so closely packed in the
cartridge case as to effectually prevent burning except on the upper or advance
surface, it may be applied without the cup, being then made large enough to fit the
case closely.
Section, will consist mainly of fine grains of very quick action whether the
intermediate section be used or not, this section b', will be separated from the one
above by the cup packing, of leather, strong paper or other approved packing
and the stronger disk j', of metal compressed paper stock or the like substance
resting on the shoulder ¹, of the shell with a central supporting standard l', to
resist the back pressure of the explosion in advance and in this standard and through
the packing or the bottom of the cup, as the case may be I propose to make a
small aperture m², communicating with the two sections of the charge at suitable
length and apply a fuse n', therein adapted to effect ignition of the lower section
from the one above in due order of time, but it may be fired by other means.
Besides the standard a series of columns 12, (Fig. 10) of small compressed cakes of
explosive material may be interspersed in the filling of the powder.
Either section of the charge may be graduated for quicker action of the latter
portion in any approved way, as for example in the manner which I have represented
in Fig. 11 wherein I represent the explosive material in the form of compressed
disks as section e', in Fig. 1, some of the disks being made with numerous holes or
recesses extending upward from the lower side any predetermined distance, the
purpose of which is to cause the fire to penetrate the lower part quicker after
reaching said holes than the upper part and in addition to this I will also in some
cases provide a layer of loose quick powder e', under the surface of the disk. When
the fire reaches the holes it instantly ignites the quick powder which breaks up and
throws the parts of the disk forward into the burning gas with intense effect.
The disks of the portion of the charge in advance of section b, may be arched as
represented in Fig. 10, for greater power of resisting the back pressure of the
explosion and preventing the crushing of the hinder part of the charge, the
partition,, will be correspondingly arched in such case. The whole charge may
consist of these graduated disks if desired, and for solid shot which it is not
necessary to cushion so effectually as shells, I will employ the inverted section of
the cartridge represented in Fig. 10 preferably omitting the cork sabot although it
may be used with good results if desired, said inverted portion of the cartridge
preferably consisting of one or more differential disks or layers, of explosive sub-
stance of like character as disk c', but may be otherwise constituted, placed in the
inverted cup, with the lower side resting on the metallic cover t¹, soldered or
brazed on to the cup and separating the charge above from the part below so as to
be fired a little later than said lower part after the fire of said lower part has
melted disk t', apart from the cup, thus providing for burning both ways and in
opposition and combining the effects of the opposing forces in ejecting the projectile
with greater force.
The bottoms, of the cup containing this portion of the charge will also be
detachable from the cylinder same as the other and for the like purpose, the flange
of the cylinder will preferably be turned outwardly and it and the bottom s', may
fit the bore of the gun suitably to serve for the gas check between the cartridge
and the projectile.

page_text: To facilitate charging the lower section of the cartridge after having applied the
packing, which it is preferable to secure by a cement joint at the shoulder k¹,
before filling said section, I make an aperture through the bottom and preferably
in the base of the standard at o', through which to introduce the powder and close
it with a plug afterwards.
I may in some cases prefer to fire this upper or forward part of the charge
first the lower or rear part being fired later by the gas, the cover being in such
case soldered to the top of the case a¹, instead of to the cup, in such case the
electric wire for communicating the spark will of course connect with the charge
above the cover as shown in Fig. 10.
It will be seen that in consequence of the projectile being in motion when the
principal portion of the charge is exploded the impulse will be mainly directed
against the projectile with much less reflex action against the sides of the bore of
the gun than when the inertia of the projectile opposes the greater explosion, and
besides, larger space will be afforded for the explosion which will be thereby more
perfect because of better combustion and will be correspondingly more powerful.
In Figs. 10 and 11 I have represented the metallic cup f¹, containing the
upper or advanced portion of the charge as having the bottom made separately
from the cylinder and cemented, soldered or otherwise temporarily fastened to
the cylinder by the flange », on which the margin of the disk is placed so that the
heat of the explosion will separate and discharge it only, the cylinder remaining in
the cartridge case and thus the expulsion of objectionable objects from the
cartridge will be reduced to the minimum.
In Fig. 2 I represent my improved gas checks for the projectile which may
consist of the thin band flaring at one side and placed on the projectile with the
flaring side downward and secured by a stronger band v', shrunk on over the upper
part closely fitting the projectile with a packing of cork in the flaring part for
elasticity, or it may be a band of cork w¹, secured by a metallic band, shrunk on
over each margin, the middle portion of the cork band being adapted to bulge out
sufficiently to pack in the bore of the gun.
I am aware that dynamite charges have been cushioned within the shell, and a
cushion of felt has been interposed between the rear of the shell and a sabot of
wood, and coiled springs and a follower have been applied to the rear end of the
shell and I do not claim either the cushioning of the charge in the shell or the
cushion behind the shell broadly, my invention being limited in these respects to
the materials used.
I have found in practical experiments that cork cushions as I use them for these
purposes have a practically different and far more effective quality than rubber,
felt, or springs, and ensure successful operation where these fail.
Rubber is practically incompressible and only cushions when the conditions are
such that it can find room in one direction in proportion as it yields in another
which is not the case when confined in a gun barrel in which, consequently, it fails
altogether as a cushion by confinement laterally in the bore.
The structure of felt is too unsubstantial to afford the powerful elastic resistance
required and the same is true of the springs, and also of rubber when unconfined
laterally.
The natural consistency of cork is peculiarly adapted for graduating the powerful
shocks of this service its structure is such that its power of resistance before yielding
to any extent is very great, and its power of cushioning is not exhausted by the
greatest shocks and is not hindered by lateral confinement, it yields in the direction
of the impelling force against it without material lateral displacement and is
therefore not materially obstructed by friction on the sides of the bore of the gun
as rubber is.
It will be desirable in practice to employ one or more metallic disks as w, between
some of the layers of the cork sabot for a gas check.
I am also aware of the multicharge gun in which there are several charges

page_text: located in branch chambers at intervals along the gun to be fired in succession and
I make no claim to such device, my improvements in the cartridge being confined
to the differential charge contained in one cartridge.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:-
1st. In a shell for explosives, the explosive charge consisting of the coil or roll
of corrugated paper holding dynamite or other explosive element in the interior
spaces substantially as described.
2nd. In a shell for explosives, the explosive charge consisting of the coil or roll
of corrugated paper saturated with nitro-glycerine and holding dynamite or other
explosive element in the interior spaces substantially as described.
3rd. In a shell for explosives, the explosive charge consisting of a coil or roll of
corrugated paper saturated with nitro-glycerine and holding dynamite or other
explosive element in the interior spaces, and enclosed in a cylindrical case substan-
tially as described.
4th. In a shell for explosives, a charge of nitro-glycerine or other high explosive
surrounded by another explosive of lower grade substantially as described.
5th. In a shell for explosives, the explosive charge consisting of the coil or roll
of corrugated paper holding dynamite or other explosive element in the interior
spaces, and surrounded with explosive powder substantially as described.
6th. In a shell for explosives, the explosive charge consisting of the coil or roll
of corrugated paper holding dynamite or other explosive element in the interior
spaces, and a series of trays containing an explosive element and having protective
rims and placed one above another substantially as described.
7th. In a shell for explosives, the explosive charge consisting of the coil or roll
of corrugated paper holding dynamite or other explosive element in the interior
spaces, the series of trays containing an explosive element and having the protective
rims and placed one above another, and another lower grade explosive element
surrounding the charge substantially as described.
8th. In a shell for explosives, a cushion of cork interposed between the explosive
charge and the bottom of the shell substantially as described.
9th. In a shell for explosives, a cushion of cork interposed between the
explosive charge and the front end of the chamber of the shell substantially as
described.
10th. In a shell for explosives, the dynamite charge surrounded by a layer of powder
or other explosive element in combination with the detonating or other exploding
device adapted to ignite the said surrounding explosive element prior to the
ignition of the dynamite charge substantially as described.
11th. In a projectile, the spiral compressible and expanding wings or vanes
attached to the recessed rear portion of the same substantially as described.
12th. In a projectile, the spiral compressible and expanding wings or vanes
attached to the recessed rear portion of the same and consisting of two leaves or
plates substantially as described.
13th. In combination with a shell for explosives, a cushioning sabot of cork
interposed between the rear of the shell and the cartridge for firing the shell from
the gun substantially as described.
a
14th. The combination with a projectile, of a differential cartridge having
graduated charge adapted for comparatively slow initial and accelerated later action
substantially as described.
15th. The combination with a projectile, of a differential cartridge having a
graduated charge adapted for comparatively slow initial and accelerated later action
in both directions from the igniting point along the bore and with opposing effect,
the one part on the other substantially as described.
16th. In combination with the projectile, a cartridge having a charge of slow

page_text: powder in advance, a charge of quick powder in rear, and means for firing the
slow charge slightly in advance of the firing of the quick charge substantially as
described.
17th. In combination with a shell, a cushioning sabot of cork in rear of the shell,
a firing cartridge having a starting charge in advance, a following charge in rear
and means of firing the starting charge slightly before the firing of the following
charge substantially as described.
18th. The combination in a cartridge for firing heavy projectiles, of a differential
charge comprising a comparatively slow burning powder in advance adapted for
overcoming the inertia of the projectile and a following larger portion adapted for
largely accelerating and mainly effecting the flight of the projectile, and means of
firing the advance portion prior to the firing of the following portion substantially
as described.
19th. The combination in a cartridge, of two differential portions of the charge
graduated in opposite directions along the cartridge from the igniting point and
adapted for firing with opposing effect the one on the other substantially as
described.
20th. The combination in a cartridge, of two differential portions of the charge
graduated in opposite directions along the cartridge from the igniting point, the
partition separating the said portions, and separable from the container of the
forward portion by the heat of the explosion of the said rear portion, and means
of firing the charge in rear or below said partition substantially as described.
21st. The combination in a cartridge for firing heavy projectiles, of a differential
charge comprising a small portion of comparatively slow burning powder in advance
adapted for overcoming the inertia of the projectile, and a following larger and
more powerful portion consisting of two sections of successively quicker and more
powerful action adapted for largely accelerating and mainly effecting the flight of
the projectile, and means of firing the several portions of the charge successively
substantially as described.
22nd. The combination in a cartridge, of the advance and rear portions of the
charge separated by a partition resting on the shoulder of the shell case and an
intermediate standard substantially as described.
23rd. The combination in a cartridge, of the advance and rear portions of the charge
separated by a partition with an aperture communicating between the two portions,
and a fuse in said aperture for igniting the rear portion from the advance portion
through the fuse substantially as described.
24th. A differential cartridge for firing heavy projectiles having a graduated
charge adapted for comparatively slow initial and accelerated later action sub-
stantially as described.
25th. A differential cartridge for firing heavy projectiles consisting of one or
more compressed disks of explosive material having holes or recesses in the lower or
rear side substantially as described.
26th. A differential cartridge for firing heavy projectiles consisting of one or
more compressed disks of explosive material having holes or recesses in the lower or
rear side, in combination with a layer of loose quick explosive material under or back
of said disk substantially as described.
27th. A differential cartridge for firing heavy projectiles consisting of one or
more compressed disks of explosive material in a cup placed above or in advance
of the lower or hinder portion of said charge, said cup having the bottom secured
detachably by the heat of the explosion and being adapted for expulsion from the
gun independently of the cylindrical portion of the cup substantially as described.
28th. In a cartridge for firing projectiles, one or more compressed disks of explosive
material above or in advance of the hinder portion of the charge, and being arched
for protection of said hinder portion of the charge from the back pressure of the
advance portion of the charge substantially as described.
29th. The combination with a projectile, of the expanding gas check surrounding

page_text: the same and secured with a band shrunk on and binding the same upon the surface
of the projectile substantially as described.
30th. The combination with a projectile, of the expanding gas check consisting
of the band of sheet metal surrounding the same and having the flaring lower or
rear side and secured by a band shrunk on the upper or forward part substantially
as described.
31st. The combination with a projectile, of the expanding gas check consisting of
the band of sheet metal surrounding the same and having the flaring lower or rear
side, and secured by a band shrunk on the upper or forward part and said flaring
part having a packing of cork substantially as described.
32nd. The combination in a cartridge of two portions of the charge, the partition
separating said portions and separable from the container of the lower or rear
portion of the charge by the heat of the explosion of the forward part of the charge,
and means of firing the forward portion of the charge next above said partition
substantially as described.
33rd. One or more disks of solid compressed powder or other explosive element
applied to the rear of the projectile and adapted to be fired prior to or independently
of any charge or charges at the base.
Dated the 16th dox of Danambar 1800.
PHILIP M. JUSTICE,
Associate Agent.