Year: 1887

page_text: Date of Application, 28th June, 1887.
Specification Accepted, 12th Aug.,
1887.
ECCE Cus.
I NATHANIEL Waterman PRATT, residing at 402, Adelphi Street, Brooklyn, in
the County of Kings, and State of New York in the 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 :-
This invention relates to ordnance in which projectiles are discharged from a gun
by compressed air, or other compressible fluid agent, the purpose being to avoid the
concussion incident to the discharge by an explosive agent, and whereby the employ-
ment of a shell containing a highly explosive charge is rendered practicable; the
latter being exploded by concussion or otherwise at the time of impact upon the
target.
The object of the invention is to provide means for quickly restoring and maintain-
ing the normal firing pressure in the firing reservoir; to so locate the movable jointed
connection of the firing port as to relieve the same from pressure except during the
act of firing and to acquire an accurate control over the range of the projectile by a
predetermined pressure charge.
To these ends the invention consists of a double system of compressed air or other
gaseous fluid reservoirs, one reservoir of said system being used as a firing and the
other as a magazine reservoir; the latter charged with an excess of pressure for
restoring the reduced pressure in the former, subsequent to each act of firing, or at
suitable intervals.
The invention also consists in universally jointing the firing port connection (as by
a ball and socket joint) proximate to the point of connection to the gun barrel,
whereby a universal training movement of said barrel, horizontally, vertically or
obliquely, is permitted, and the firing valve located at a point between the pressure.
source and the said connection, for the purpose of relieving the same from pressure
when the firing valve is closed. The invention further consists of an automatic firing
valve, and valve operating device whereby the action of said valve is regulated to
deliver the compressed fluid in predetermined quantities, said quantities being variable
at will for the purpose of controlling the range of the projectile, irrespective of the
control of the operator during the act of firing.

page_text: the essential features which I claim as new.
I have shown in the accompanying drawings a movable gun system embodying one
form of structure by which the various features of my invention may be carried into
practice; but it is obvious that the double reservoir system and firing valve mechanism
herein shown are equally applicable to a fixed gun system, i.e. one having the barrel
placed at a permanent angle of elevation.
Referring to the drawings, in which like figures of reference represent like parts
throughout the several views:
Figure, 1, is a side elevation of a pneumatic gun.
Figure, 2, a plan view of figure, 1.
Figure, 3, an enlarged vertical central section of the rear portion of the same.
Figure, 4, a plan view of the lower portion of figure, 3, namely, the revolving
truck, the foundation, and the ball of the ball and socket pipe joint.
and
Figure, 5, an enlarged vertical section of the firing valve operating mechanism;
Figures, 6, to, 10, inclusive detail views of the said operating mechanism.
1, figures 1 and 2, is an elongated barrel composed of sections bolted together by
flanges, 2, and mounted upon a truss frame, 3, being secured thereon by means of
straps, 4, and a casting, 5, composing the breech of the barrel.
The whole is capable of swinging vertically upon the trunnions, 6, which are
supported in pillow blocks, 7, of a revolving truck, S. The truck, 8, rests upon truck
wheels, 9, which travel on the circular track, 10, of the foundation, 11, during the
horizontal training movement of the gun. The truck, 8, has a forwardly projecting
frame or carriage, 12, provided with a forward truck, 13, moving on a track. 11, and
which supports the weight of the gun by agency of the hydraulic cylinder, 15, and
plunger, 16, pivoted respectively at, 17, and, 18, to the frame of said carriage, and the
frame of the gun barrel.
The casting, 19, fixed to the foundation is provided with a grooved rim, 20, for the
reception of a cable, 21, secured thereto. The extensions of the cable, 21, are passed
over sheaves, 22, upon the truck frame, 8, and thence are held taut by pistons in the
hydraulic cylinders, 23; the latter being secured to the carriage, 12. The piston
rods, 24, extend partly through the sleeves, 25, fastened to the carriage, and are
coupled at points, 26, to the ends of the cable; the said sleeves being for the purpose
merely of protecting the parts; the gun is by this construction capable of vertical or
horizontal training movements, or both simultaneously, according to the directed flow
of water conveyed through pipes to the several hydraulic cylinders.
The breech of the gun is provided with a hinged valve, 27 figure, 3, for the intro-
duction through the opening, 28, of the projectile. The hinged valve may be provided
with a suitable returning spring to assist in throwing it home to its seat preparatory
to applying the firing pressure.
The movable ball and socket pipe joint, 29, (fig. 3) is located in line with the
trunnions, 6, and in the vertical axis of the revolving truck, 8, acting as a pivot
therefor and permits the universal movement required for the training of the
gun. The socket is made separable as shown, having a central flanged division
bolted together in the usual manner of similar joints. The ball part, 30, is secured
to, or forms a part of the casting, 19, and to the flange, 31, of said casting is secured
the casing, 32, of the firing valve, to which the reservoir pipe is bolted.
The magazine reservoir, 33, shown by dotted lines, figure, 1 and firing reservoir, 34,
are preferably placed beneath the ground; the latter reservoir being connected to the
firing valve by the pipe, 35, having a throttle valve, 36, figures, 1, and 3. The
magazine and firing reservoirs are capable of communication through the tube, 37,
carried for convenience to the interior of the foundation and controlled by a cock, 38.
The firing valve consists of a plunger, 39, fig. 5, having different areas presented
by its opposite ends; the greater being exposed to the chamber, 40, in which the

page_text: flange, 41, of said valve acts as a piston; the space, 42, back of said flange being
open to the atmosphere. The diameter of the valve end of the plunger is slightly
in excess of the exterior margin of the valve seat, 43, which feature causes the valve
to start from its seat the instant pressure in the chamber, 40, falls sufficiently below
that within the pipe, 35. The top of the valve is weighted by a tapering head, which
by its form causes a comparatively gradual discharge of pressure at the initial descent
of the valve, and avoid a blow to the projectile which would result by overcoming
its inertia with an abrupt shock of pressure to the intervening space between the said
valve and said projectile. The gradual discharge aforesaid first charges the inter-
vening space with a pressure cushion and starts the projectile before the impelling body
of fluid acts with full force thereon. The chamber, 40, is charged and exhausted
through the port, 45.
The automatic valve operating mechanism represented by figs. 5, to, 10, inclusive
consists of a piston exhaust valve, 46, having a cup shaped end fitting the seat, 47, of
the exhaust passage, 48, and also sliding air tight in the cylindrical chamber, 49, so as
to control the induction pipe, 50, which latter is connected as shown in fig. 3, to the
main reservoir pipe. The stem, 51, of the exhaust valve, 46, extends air tight through
the fixed bushing or diaphragm, 52, held in place between the sections, 53, and, 32,
of the valve casing and upon the end of said stem is secured the operating piston, 54,
sliding air tight in the cylindrical chamber, 55. The piston, 54, is of greater diameter
than the piston valve, 46, and the chamber, 55, communicates through the port, 56,
located in front of the piston, 54, and with the port, 58, of the cut off valve, 59,
figs. 7, and, 8, the cavity 57, being connected to the port, 58. The portion of the
chamber, 55, back of the piston, 54, acts as an air cushion for returning the valve
when it is forced. out. Pressure conveyed through the pipe, 60, from the main
reservoir pipe, (fig. 3) to the back of the cut off valve, 59, is alternately charged to
the chamber, 55, and exhausted thorefrom through the exhaust pipe, 61, by the
rocking movement of the said valve; the same being actuated by means of its
arms, 64, 65, by the latch, 62, figs. 5, 6, and, 9, when moved to the position shown
by fig. 7, and returned to the position shown by fig. 8, by the stem, 63, of the
piston, 54.
I do not however, confine myself to the cut off valve construction shown in the
accompanying drawings, as means of charging the chamber, 55, and exhausting
the pressure therefrom. The said valve may be constructed having a charging
function only, dispensing with its exhausting function, and may be operated with a
positive connection directly or indirectly to the band lever, 66; and an independent
valve of any suitable construction may be employed; to be released when the latch
is tripped for the purpose of exhausting said chamber, 55. The latch, 62, is operated
by the hand lever, 66, so that by the downward movement of said lever as in figure, 6,
the enlargement of the slot, 67, figure, 9, is brought into line with the stem
shoulders, 68, of the stem, 63, fig. 10, permitting the pressure in the chamber, 55, to
throw said stem out, shifting the valve, 59, to its exhausting position; whereupon the
piston, 54, and stem, 63, is returned by the pressure from the pipe, 60, on the back of
the valve, 46, and by aid of the air cushion aforesaid, and the latch, 62, reset by the
upward movement of the hand lever.
In order to insure the accuracy of the predetermined firing charge, it will be
observed that the latch, 62, trips the piston, 54, while the same is under pressure, by
an instantaneous movement, irrespective of the speed with which the gunner handles
the firing lever, 66. The exhaust pipe, 61, is provided with a controlling escape valve
or cock, 69, of any suitable construction, having a handle and graduated indicating
disk by which it may be set to predetermine the period of the exhausting action herein
described, which in turn regulates the action of the firing valve.
In order to avoid an unnecessarily fine adjustment of parts in the construction of
the escape valve, 61, the volume of fluid which must be exhausted through the same,
is increased by means of the chamber enlargement of the chamber, 55, so that a
proportionate enlargement of the valve opening and consequently greater movement
is acquired decreasing the effects of a possible variation in the operating adjustment,

page_text: The magazine reservoir being charged from a suitable source, (as a compressor)
with a pressure exceeding that of the desired firing pressure, say, 2,000, lbs. per
square inch, and the firing reservoir being charged with a firing pressure say
of 1,000, lbs. per square inch, the operation of my invention is as follows:-
The pressure is charged through the pipe, 35, both to the annular space, 70, about
the firing valve, and to the chamber, 40 through the tube, 50, and port, 45. The
firing valve is thereby held against its seat by the greater pressure area of its lower
side. The pressure is also admitted through the pipe 60, to the back of the valve, 59.
The gun is elevated to the required angle with regard to the desired limits or range,
and with consideration of the degree of firing pressure at command.
The projectile having been introduced into the barrel through the breech
opening, 28, and the valve, 27, closed the gun is ready for action. The action of
the firing valve mechanism may be considered as divided into four separate acts :-
First, latching the exhaust valve, 46, in its closed position by an upward movement
of the hand lever, 66, and subsequently charging the pressure side of the exhaust valve
piston, 54, by a continued upward movement of said lever, to the position of fig. 5,
preparatory to firing. Second, the firing movement; namely, the depression of the
lever, 66, tripping the latch, 62, the pressure on the greater piston area, 54, driving
the exhaust valve, 46, open. Third the dwell open due to the retarding action of the
controlling escape valve, 69, upon the exhaust of the independent system of pressure
on the piston, 54; Fourth the return of the exhaust valve, 46, to its seat due to
constant pressure back of the said valve from the pipe, 50.
The action thus described of the exhaust valve, 46, exercises a corresponding
control over the action of the firing valve, 39, the movement of which is divided into
three separate acts: first, an instantaneous wide open motion; second a variable
dwell in this position; and third an instant closure.
It will therefore be understood that the variable dwell aforesaid is subject to the
positive control of the adjustable escape valve, 69, and that the personal equation of
the gunner; that is to say, his control over the volume discharged during the act of
firing, is eliminated by this construction the range of the gun (for a given angle
of elevation) being variable by a predetermined independent adjustment of the said
escape valve, rendering the subsequent action automatic.
Having now particularly described and ascertained the nature of the said invention
and in what manner the same is to be performed I declare that what I claim is :-
1. In a pneumatic gun system the combination with a gun barrel and pressure
reservoir of an interposed firing valve capable of delivering predetermined quantities
of compressed gaseous fluid from said reservoir into said barrel, said quantities being
variable at will, for the purposes described.
2. In a pneumatic gun system, the combination of a gun barrel, a firing reservoir,
and an interposed firing valve capable of delivering compressed gaseous fluid from
said reservoir to the said barrel in quantities variable at will, with a secondary or
magazine reservoir, the same being charged with gaseous fluid at a higher pressure
than that of said firing reservoir, and having a controllable communication therewith,
for the purpose set forth.
3. In a pneumatic gun system, the combination with a gun-barrel capable of both
vertical and horizontal movement about a fixed centre without severing its means of
reservoir connection, of a stationary pressure reservoir, and an interposed firing valve
capable of delivering compressed gaseous fluid from said reservoir to said barrel in
quantities variable at will substantially as described.
4. In a pneumatic gun system, the combination with a gun barrel capable of both
vertical and horizontal movement about a fixed centre without severing its means of
reservoir connection, a stationary firing reservoir, and an interposed firing valve
capable of delivering compressed gaseous fluid from said reservoir to the said barrel in
quantities variable at will, of a secondary or magazine reservoir, the same being
charged with gaseous fluid at a higher pressure than that of said firing reservoir, and
having a controllable communication therewith, for the purposes set forth.

page_text: 5. In a pneumatic guu system, the combination of a gun barrel capable of both
vertical and horizontal movement about a fixed centre, a stationary pressure reservoir,
a reservoir pipe connection (as a ball and socket joint) capable of yielding to the
barrel movements aforesaid, and a firing valve, the said firing valve interposed between
the said yielding connection and the reservoir, for the purposes set forth.
6. In a pneumatic gun system the combination with an automatic firing valve
having an actuating pressure chamber substantially as shown, of an automatic
operating mechanism for controlling the charge or discharge of pressure in said
chamber, the said mechanism consisting of an exhaust valve controlling both the
induction and eduction of said pressure by means of an automatic operating piston
connected to said exhaust valve, the said piston being in turn actuated from an
independent pressure application, actuated by a controlling means, (as a cut off valve)
a latch mechanisu and an adjustable escape valve, all substantially as described.
7. In a firing valve operating mechanism, the combination with an exhaust valve
substantially as shown, for controlling the induction and eduction of pressure to or
from the actuating pressure chamber of an automatic firing valve, of an independent
automatic pressure system for operating said exhaust valve whereby the latter is
caused to exhaust pressure by the act of the operator, and to replenish pressure by the
automatic action of said independent system such action being regulated by the
predetermined adjustment of a variable escape valve, substantially as described.
8. In a pneumatic gun system, an automatic firing valve, the same being capable of
the following distinct periods of action; first an instantaneous wide open movement;
second a variable predetermined dwell in its open position; and third, an instantaneous
closing movement; the said valve having means substantially as described for causing
the said periods of action.