Improvements in Dynamite Guns.
Year: 1898

page_text: Date of Application, 22nd Feb., 1898-Accepted, 26th Mar., 1898
COMPLETE SPECIFICATION.
Improvements in Dynamite Guns.
I, WILLIAM MOORE MCDOUGALL, of 43, Sussex Avenue, East Orange, New Jersey,
United States of America, 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 :-
Our invention relates to breech loading pneumatic guns, for throwing projectiles
charged with dynamite or other high explosive, of that type in which the air
pressure is set up by means of ordinary or any suitable gun powder.
It is well known that in weapons of this class the gun powder must not be so
placed in the gun that, when ignited, its impact will be exerted directly upon the
base of the projectile as in ordinary guns, and various methods have been adopted
for obtaining the required propulsive force while avoiding the danger of the direct
action of the powder gases upon the projectile.
One of the best known plans for achieving this consists of a gun in which the
powder charge is ignited in an air chamber separate from that in which the projectile
is located, the generated gases creating an air pressure which reaches the base of
the projectile only after passing through a connecting passage.
Our invention is an improvement upon this particular type of gun.
In the gun
mentioned, as heretofore constructed, the powder charge has been placed in one
end of the chamber while the passage leading to the projectile chamber is at the
other end of the same. When the gun is fired, the slow burning powder used is
carried forward by the current through the air chamber, and into the projectile
chamber itself. The result of this is that a portion of the powder burns directly in
the presence of the projectile and is liable to impart a shock thereto; also, on
account of this burning of powder in the projectile chamber, the parts of the gun
immediately surrounding the projectile become heated and the high explosive
carried by the projectile is liable to premature discharge, especially if the gun is
fired at short intervals. The object of our invention is to overcome these difficulties
and I accomplish this by so constructing the chambers and passages of the gun
that the entire powder charge must be burned in the combustion or explosion
chamber and nothing but the gases therefrom can be passed to the projectile or
compression chamber.
Our invention will be described in detail with reference to the accompanying
drawing in which Figs. 1, 2 and 3 are longitudinal sectional views of various forms
of my improved gun, and Fig: 4 is a section on line x, x, of Fig. 3.
In the several figures A represents the gun barrel which is a simple straight tube.
At the base of this is attached by any suitable means a part B containing a
chamber b, which is known as the compression chamber and in which the air is
compressed by the explosion. At the rear of this chamber a movable
breech-block C of suitable construction is inserted axially in line with the gun
barrel, and through the breech the projectile may be introduced.
E is a casting
forging or the like provided with a combustion chamber e. This may be made in

page_text: This
The
one piece with the part B, as shown in Figs. 2 and 3, or it may be made separately,
as shown in Fig. 1. It may be a projection bodily entering the chamber b as shown
in Figs. 1 and 2 or it may form an offset of the part B as shown in Fig. 3.
combustion chamber e is provided with a removable breech block f, and is preferably
elongated and cylindrical, the breech-block being axially located at one end.
powder charge, represented by p, is introduced through the breech-block opening
and deposited in a position in front of the block when the latter is in place. The
combustion chamber e communicates with the compression chamber b through
one or more ports e¹ which are formed at the rear end of the chamber e, the
forward end of the said chamber being entirely closed by the solid wall of the
casting.
In the operation of the gun the firing of the cap and the initial burning of the
charge throws the entire powder charge into the forward end of the combustion
chamber and past the ports e¹. The powder is entirely burnt in the forward end of
the chamber and the gases generated thereby pass backward and laterally through the
ports e¹ into the compression chamber, compressing the air therein and exerting
the pressure against the base of the projectile without any serious or violent initial
shock thereto. There being no exit at the forward end of the combustion chamber
for the powder it is forced to burn at this end and the generated gases escape by
their own pressure backward. This operation is common to all types of gun shown
in the drawing. In Fig. 1 a compound breech-block is used, the block which closes
the compression chamber being provided with a charge pocket for the combustion
chamber. This type increases the total length of the gun inasmuch as the
projectile must be placed forward in line with the explosion chamber. When
the explosion chamber can be placed at one side, as shown in the other figures, the
gun is shorter, but occupies more space laterally. In Figure 3 the lip g breaks
the force of the air or gas against the tail of the projectile.
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 :-
1. A pneumatic gun, provided with a receptacle or pocket for the explosive
charge, a chamber or space in front of the charge into which it is projected when
fired, this chamber being closed at its forward end, and a projectile chamber
communicating with the first mentioned chamber at or near its rear end, all
constructed and arranged substantially as set forth and as illustrated by the
accompanying drawings.
2. In a pneumatic gun, a combustion chamber provided at one end with a pocket
for the explosive charge and closed at the opposite end, and a projectile chamber
communicating therewith by a passage or passages opening laterally into the
combustion chamber at a point adjacent to the charge pocket, constructed and
arranged substantially as and for the purpose hereinbefore set forth and as illustrated
by the accompanying drawings.
3. In a pneumatic gun, a projectile chamber and a combustion chamber, the
combustion chamber being open at one end to the projectile chamber and closed
at the other, and provided with a pocket. at its open end for the explosive
charge, constructed and arranged substantially as hereinbefore described, and as
illustrated by the accompanying drawings.
4. A pneumatic gun having a compression chamber, and a part containing a
combustion chamber projecting into the compression chamber, substantially as
herein before described and as illustrated by the accompanying drawing.
5. A pneumatic gun having a compression chamber, a part containing a com-
bustion chamber projecting into the compression chamber, means for supporting the
powder charge in one end of the combustion chamber, and a port leading from the
combustion chamber at or near the charge support, into the compression chamber,
constructed and arranged substantially as hereinbefore described and as illustrated
by the accompanying drawings.

page_text: 6. A pneumatic gun, constructed and arranged substantially as and for the
purpose herein before described and as illustrated by the accompanying drawings.
n 1000
W. E. HEYS & SON,
Agents for the Applicants.