Improvements relating to Guns, Chiefly Designed for Use with Projectiles Containing Dynamite and similar Explosive Materials.
Year: 1887

page_text: Date of Application, 15th Dec., 1887
Complete Specification Left, 15th Sept., 1888
Complete Specification Accepted, 15th Dec., 1888
PROVISIONAL SPECIFICATION.
Improvements relating to Guns, Chiefly Designed for Use with
Projectiles Containing Dynamite and similar Explosive
Materials.
I, HIRAM STEVENS MAXIM, Mechanical Engineer, 57° Hatton Garden, London, E.C.
do hereby declare the nature of this invention to be as follows:-
My invention relates to a system of constructing an air gun in such a manner
that the length of the barrel may be greatly reduced, the pressure of air greatly
reduced and at the same time, a very high muzzle velocity given to the projectile.
To accomplish this, I construct an air gun on any well known principle, but instead
of charging it with compressed air in the ordinary way, I charge it with air con-
taining a small per centage of volatile petroleum or combustible gas; as per example,
I mix sufficient gasoline with the charge of air so that there is just sufficient oxygen
in the air to convert the hydrogen into water, and the carbon into carbonic acid
gas. This mixture may be of about half the pressure ordinarily employed in an air
gun. Upon firing, a quantity of this explosive mixture of gas and air is allowed
to enter the barrel, and as it forces the projectile forward, to say from one-quarter
to one-half of the entire length of the barrel, I cause an explosion to take place
when the pressure will be instantly increased to about eight fold. I thus greatly
increase the pressure without increasing the weight or the density of the gas which
propels the projectile.
The presence of burning gas in the air also prevents refrigeration, and also
prevents the appearance of vapours in the air at the instant of discharge.
For the purpose of igniting the charge, I may employ any of the well known
means, I however prefer to use a detonating cartridge which may be placed in the
side of the barrel at any distance from the breech that may be required, the exploding
cartridge being placed in a tube, and the tube secured into a hole in the side of
the barrel.
The cartridge is made also so as to slide about one-quarter of an inch in the tube,
and the plug which is behind it is provided with a sharp projection which strikes

page_text: the primer when the cartridge is moved back against it. When the cartridge is
thus placed in position and the gun is fired, no effect takes place until after the
projectile has moved past the hole and allowed the compressed air to impinge the
end of the cartridge, when the cartridge will be forcibly driven back in its tube,
the primer being brought in contact with the sharp projection and the explosion which
follows ignites the explosive gases in the barrel of the gun. In this manner, a gun
is rendered much more efficient than with cold compressed air, while the quantity of
air required for each discharge is much less. The quantity of gasoline required for
each discharge, is very small, the propelling power of one ounce when thus used being
equivalent to the propelling force of some pounds of gunpowder, while the pressure
generated can never exceed a certain limit which may be predetermined with exact
certainty.
Dated this Fourteenth day of December 1887

page_text: Improvements relating to Guns, Chiefly Designed for Use with
Projectiles Containing Dynamite and similar Explosive
Materials.
1, HIRAM STEVENS MAXIM, of 57" Hation Garden, in the County of Middlesex,
Mechanical Engineer, 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:-
My invention relates chiefly to guns of the kind or class commonly known as
dynamite-guns," that is to say,-guns which are designed for use with hollow
projectiles or shells charged with or containing blasting-gelatine or similar highly
explosive compounds.
It has heretofore been customary to utilize compressed air in dynamite-guns for
discharging the projectiles or shells therefrom, and, in order to obtain a high muzzle
velocity of the projectile or shell, it has been necessary to make such guns with very
long barrels, and to employ air under very high pressure.
The main object of my invention is to provide for utilizing the expansive and
explosive forces of a mixture of gas and air under pressure for the purpose of
discharging a projectile or shell from a gun.
By my invention, 1 am enabled to greatly reduce the length of the barrel and the
pressure of air employed, as compared with the dynamite-guns heretofore used, and,
at the same time, to obtain a very high muzzle velocity of the projectile or shell.
Instead of charging the gun with compressed air in the ordinary manner, I charge it
with a mixture of compressed air and volatile petroleum or other hydro-carbon or
combustible gas; for example. I mix a quantity of gasoline with the charge of
compressed air so that there is just sufficient oxygen in the air to convert the
hydrogen of the hydrocarbon into water, and the carbon into carbonic acid gas. This
mixture may be used at a pressure equal to about one-half of that ordinarily employed
in air-guns or dynamite-guns.
In using the gun, a quantity of this explosive mixture of hydrocarbon vapor or gas
and air is admitted into the barrel under pressure. I provide means whereby, when
the projectile has been driven forward through say from one-quarter to one-half of the
entire length of the barrel by the expansive force of this mixture of gas and air, the
said mixture will be exploded and the pressure in the barrel thus instantly increased
about eight-fold. It will be seen, therefore, that I provide for greatly increasing the
pressure applied for propelling the projectile or shell, without increasing the weight
or the density of the gas used for this purpose.
Moreover the heat generated by the combustion of the mixture of gas, and air

page_text: prevents refrigeration and increases the expansion of the air; it also prevents the
formation of vapors in the air at the instant of discharge.
For the purpose of igniting the charge, I may employ any well-known or suitable
device. I prefer, however, to use a detonating cartridge placed in a chamber or cavity
in the side of the barrel at any required distance from the breech. The said cartridge
is so arranged that it may be moved outward from the axis of the barrel as hereinafter
described through a distance of about one-quarter of an inch, and a sharp projection
or pointed stud is provided in the said chamber or cavity, against which the primer
will strike when the cartridge is thus moved outward. When the said cartridge is
placed in the said chamber or cavity and the compressed air and gas are admitted
into the barrel to discharge the gun, no effect is produced by means of the said
cartridge until after the projectile has passed the aperture of the said chamber or
cavity the compressed air then impinges upon the inner end of the cartridge, and
forcibly drives the same outward in its chamber or cavity, thus bringing the primer
into contact with the said sharp projection or stud, whereby the said cartridge is
exploded so that it ignites the explosive mixture in the barrel of the gun.
In this manner a gun is rendered much more efficient than with cold compressed
air, while the quantity of air required for each discharge is much less. The quantity
of gasoline or other hydrocarbon required for each discharge is, moreover, very small,
the propelling power of one ounce of gasoline when thus used being equivalent to the
propelling force of several pounds of gunpowder, while the pressure generated can
never exceed a certain limit which may be predetermined with great exactitude.
I can, if desired, adapt existing dynamite-guns for the purpose of my invention.
I prefer, however, to construct a gun as shown in the accompanying drawing, in
which
Figure 1 is a horizontal central section of one form of my improved gun, and
Figure 2 is a similar view of another form or modification thereof.
Like letters indicate corresponding parts throughout the drawing.
A is the barrel of the gun.
B is a chamber into which the compressed air and gas
are to be introduced as hereinafter described, and which is provided with trunnions B
whereby the gun is to be supported in a carriage or mounting. C is a hollow cylinder
or tube arranged within the chamber Band fitted to slide longitudinally in guides a, a¹.
This tube bears against the rear end of the barrel A and forms an extension or prolon-
gation thereof. The adjacent ends of the barrel A and tube Care made with true plane
surfaces to ensure tightness of the joint between the same. D is a chamber formed
in the rear end of the gun for the purposes hereinafter specified. E is the projectile
or shell which is to be charged with blasting-gelatine or similar explosive compound.
In the gun shown in Figure 1, the tube is closed at the rear end by a cap b
fitting into the said tube and provided with a guide-rod or stem & fitted to slide in a
recess or cavity c¹ formed in a cap c which is preferably provided with a divided or
interrupted screw-thread and is tightly screwed into the rear end of the chamber D.
A spring d placed in this recess or cavity bears at one end against the cap c and at
the other end against the said stem b'. This spring tends to keep the tube C pressed
against the rear end of the barrel A, and will effect or assist in effecting the forward
or return movement of the said tube after it has been moved backward as hereinafter
described and the projectile or shell has been discharged from the gun.
The projectile or shell E is provided with a tail consisting of a tube e having
secured therein at, or near its rear end vanes or blades e designed to impart rotation
to the said projectile or shell in its flight. A detonating charge is placed in the
tube e and is held therein by a pin which will be broken or sheared by reason of
the inertia of the charge when the projectile or shell is discharged from the gun. A
strong pin eis, moreover, fixed in the tube e to serve as a stop or abutment for the
said charge during the flight of the shell. The tube e is perforated as at ³ to
permit freedom of movement of the charge therein, and a pointed stud e* is provided
at the forward end of the said tube e for exploding the said charge or detonator when
the shell strikes a ship or other object against which it is aimed, and the detonator,
by reason of its momentum, moves forward in the said tube.

page_text: The chamber B is provided with a pipe g for the admission of the mixture of air
and gas under pressure. This pipe is fitted and secured in one of the trunnions B¹
which is made hollow for the purpose.
If it is desired to mix gasoline with the compressed air, I prefer to use a device
comprising a metal casing which is formed with a screw-threaded socket h¹ whereby
it is connected with the pipe g as shown. The said casing is also formed with a
screw-threaded socket with which the supply pipe for the compressed air is to be
connected. A tube or tubular chamber or bottle of brass or other suitable material
is arranged within the said casing h, a space being left between the said tube and
casing as shown. This tube i is closed at one end by means of an ordinary cork or
other stopper normally held by friction in the neck thereof, and is to be filled with
gasoline or similar hydrocarbon. The other end of the said tube is perforated as
at 3 and another cork or plug is pushed into the said tube beyond the perforations,
as shown, and is normally held in its place by friction. The casing is closed by a
screw-cap or cover provided with handles whereby it may be readily removed
.to permit the withdrawal of the tube or bottle i when empty and the insertion of a
full bottle.
The pipe g communicates with the chamber D by means of a pipe k arranged
within the chamber B and a pipe outside the said chamber, the pipes k, being
connected by a short pipe m extending through the side or wall of the chamber B.
The pipe is perforated as at k¹ to admit the compressed air and gas into the
chamber B. The pipe is connected with a cock n whereby the said chamber D) may
be put in communication with the said pipe 7 or with the external atmosphere through
an aperture or nozzle n*.
p is a metal tube which is firmly secured in the barrel A and in which is inserted
an igniting charge or cartridge q. The said tube is closed by means of a screw-cap
or cover provided on its inner side with a pointed stud or projection. The said
cartridge is free to slide longitudinally in the said tube p for the purpose hereinafter
specified. The cap or cover r is provided with handles to facilitate the removal
and replacement thereof.
The operation of the gun above described is as follows, viz.the gun is loaded
from the breech-end by unscrewing and removing the cap c, withdrawing the cap b
from the tube C, and then inserting the projectile or shell in the said tube; the
caps b, c are then replaced. A cartridge q is, moreover, inserted in the tube p. Care
must be taken before opening the supply cock for the compressed air, that the plug n'
of the cock n is in the position shown in the drawing. On opening the supply cock
for the compressed air, the cork will be forced by the pressure thereof into the tube
or bottle and the said pressure being transmitted through the gasoline will push the
plug past the perforations 3. The gasoline will then be forced through these
perforations by the compressed air which will mingle with the vapor of the gasoline,
thus forming an explosive mixture. This mixture of air and gas will enter the
chamber B through the perforations in the pipe k. These perforations are arranged
on one side only of the said pipe to ensure the proper mixing of the air and gas by
causing the same to circulate rapidly around the tube C within the chamber B. The
mixture of air and gas also enters the chamber D through the pipe and cock n.
The said chamber D being of much smaller capacity than the chamber B, the pressure
in the former will rise more rapidly than in the latter, and will, therefore, forcibly
press the tube C against the rear end of the barrel A. When the gun is charged with
air and gas in the manner above described and the required pressure has been
attained in the chamber B, the gun is ready to be discharged and the supply of com-
pressed air may be shut off. To discharge the gun, it is only requisite to turn the
plug n of the cock n so as to permit the escape of the compressed air and gas from
the chamber D, whilst cutting off the communication between the said chamber and
the pipe . The pressure in the chamber B will then be much greater than that in the
chamber D and the tube C will be moved backward away from the barrel A by
the pressure exerted upon the surfaces C, C² of the said tube. The air and gas will
then expand and entering the tube C and barrel A will drive forward the projectile

page_text: or shell E.
As soon as the said projectile or shell has passed the inner and open end
of the tube P, the pressure of the air and gas will drive the cartridge 7 against the
pointed stud and thus explode the said cartridge, which in turn will ignite and
explode the mixture of air and gas. The projectile or shell will, therefore, be started
and moved a certain distance along the barrel by the expansive force of the compressed
air and gas, and, after a considerable momentum has thus been imparted to it, will
have its momentum largely increased by the explosive force of the mixture of air
and gas acting in conjunction with the expansive force thereof. In this manner the
projectile or shell may be caused to leave the muzzle at a very high velocity, without
being subjected to any dangerous shock or concussion such as would be imparted
to it if the mixture were exploded before the projectile or shell began to move
forward.
In the backward movement of the tube C), as soon as its rear end has passed the
aperture or passage n² of the cock n, the air remaining in the chamber D will be
imprisoned or confined and compressed, and will, therefore, act as a cushion for
diminishing the shock or concussion and will, by its reaction or expansion, assist in
effecting the return movement of the tube C.
The gun shown in Figure 2 is rifled to ensure the rotation of the projectile or shell
in its flight. In this gun, the chamber D is connected with the chamber B by a small
orifice or passages closed by a check-valve t which is provided with a spring and
which permits the passage of the compressed air and gas from the chamber D into the
chamber B, but prevents its return through the said orifice. The tube C is closed by
a piston u firmly secured to a rod » extending through the screw-cap c and formed
with a collar between which and the said cap is placed a ring or washer of leather
or other suitable material. The outer end of the rod is screw-threaded externally
and has fitted thereon a nut formed with an arm ³ whereby the said nut may be
readily turned. By tightening this nut, the ring or washer w may be compressed
between the collar and the cap c so that it bears tightly against the sides or walls of
the chamber D and effectually prevents leakage of the air and gas therefrom. The
mixture of air and gas admitted into the chamber D will, moreover, by the pressure
which it exerts upon the collar ¹, tend to still further compress the said ring or
washer. The screw-cap or plug e is provided with handles c² to facilitate its removal
and replacement.
A passage is formed longitudinally through the centre of the rod v and is con-
nected by a transverse passage with the chamber D. The passage is closed by
means of a conical valve y formed with a stem or spindle y'. A collar or sleeve y² is
fitted upon a square part 3 of the said stem or spindle. This collar or sleeve is screw-
threaded externally and fitted into a correspondingly screw-threaded hole in the rod v.
The stem or spindle y' is provided with a handle y whereby it may be turned together
with its collar or sleeve y² to open or close the passage ; the chamber D can thus,
when required, be put in communication with the interior of the tube C through the
said passages v³, vt for the purpose hereinafter specified.
To load the gun, the cap c is unscrewed and removed together with the rod v and
piston the projectile or shell is then inserted and the said cap and other parts are
replaced, and the cap is screwed tightly into the rear end of the chamber D. The
passage is closed by means of the valve y. A cartridge 7 is, moreover, placed in
the tube p.
The mixture of air and gas under the desired pressure is admitted to the chamber D
through the pipe . As the pressure rises in the said chamber, the valve t is opened
and the spring t' compressed and the mixture of air and gas passes through the orifice
or passages into the chamber B. When the required pressure has been attained in the
chamber B, the valve t is closed by the reaction of its spring t. The supply of air and
gas is then cut off and the gun is ready to be discharged.
To discharge the gun, the chamber D is put in communication with the interior of
the tube C by opening the valve y as above described, the mixture of air and gas in
the chamber D then expands and enters the tube C. An initial pressure is thus
obtained in the. said tube, and. the pressure in the chamber D is diminished until it is

page_text: considerably below that in the chamber B. The tube C is then moved backward by
the pressure in the chamber B acting upon the surface C₁ of the said tube, so that the
mixture of gas and air expands and enters the tube and barrel A and moves forward
the projectile or shell E. As soon as the said projectile or shell has passed the tube p,
the cartridge is exploded as above described with reference to Figure 1 and ignites
the mixture of air and gas.
A casing containing a bottle filled with gasoline or other volatile hydrocarbon is,
if desired, connected with the pipe /¹.
The air and gas may, however, be mixed and compressed in a suitable reservoir,
instead of mixing them as above described. In this case the aforesaid device for
containing the gasoline is dispensed with.
By the construction and arrangement of the barrel A, chamber B and tube Cas
above described, I provide for admitting the compressed air to the barrel directly, that
is to say, the compressed air does not require to pass through bent or curved
passages which would be liable to impede its movement and diminish the velocity with
which it enters the barrel. Morcover the compressed air is admitted to the barrel
simultaneously at all points around the rear end thereof, instead of being admitted
through a contracted aperture or passage:
If desired, I employ a solid rod, plug or valve instead of the said tube C.
Although I prefer to utilize the expansive force of the mixture of air and gas to
impart momentum to the projectile before the ignition of the said mixture, it is
obvious that, if desired, I can provide for the ignition of the said mixture before it
has started the projectile by its expansive force, that is to say, I can provide for the
ignition of the said mixture simultaneously with its admission into the barrel of
the gun.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I wish it understood
that I claim :-
First The herein described method of utilizing the explosive force of a mixture of
air and gas for discharging a projectile or shell from a gun.
Second A gun wherein suitable provision is made for the admission of a mixture
of air and combustible gas under pressure into the barrel and for the ignition of the
said mixture after it has by its expansive force imparted momentum to the projectile
or shell in the barrel for the purpose above specified.
Third A gun provided with a chamber which surrounds the barrel and into which
air mixed with combustible gas is to be admitted under pressure, and with a tube or
valve arranged to be held against the barrel by such pressure and provided with means
for operating it automatically or otherwise to admit the compressed air and gas from
the said chamber into the barrel, for the purpose above specified.
Fourth-The combination, with the gun-barrel, of the chambers B, D, means for
permitting the introduction of compressed air and gas into the said chambers, means
for permitting its escape from the chamber D to discharge the gun, and the sliding
tube or valve C, substantially as, and for the purposes, set forth.
Fifth In a gun wherein a mixture of compressed air and combustible gas is
utilized for the purpose above specified, the combination, with the sliding tube C, of a
removable cap or piston for closing the rear end thereof and means for withdrawing
the said cap or piston to permit the loading of the gun, substantially as set forth.
Sixth-The above described method of providing for the mixing of the compressed
air with gasoline or other volatile hydrocarbon, by means of a tube or bottle corked or
sealed in such a manner that it will be automatically unsealed or opened by the com-
pressed air, which will then mingle with the gas or vapour, substantially as above
specified.
Seventh-The provision of suitable means for causing a circulation of the mixture
of air and gas in the chamber B, substantially as, and for the purpose, set forth.
Eighth A tube or chamber in the side of a gun-barrel for containing an igniting

page_text: cartridge or charge and provided with means whereby the said cartridge or charge
will be exploded when the projectile or shell has passed the inner open end of the said
tube or chamber, substantially as, and for the purpose, set forth.
Ninth The improved gun consisting of the parts constructed and combined
substantially as described with reference to Figure 1 or to Figure 2 of the.
accompanying drawing and operating as, and for the purpose, specified.
Dated this on day of September 1000.
HIRAM S. MAXIM.
Haseltine, Lake & Co.,
45, Southampton Buildings, London,
Agents for the Applicant.