Improvements in or relating to Pneumatic Guns
Year: 1889

page_text: Date of Application, 30th Oct., 1889
Complete Specification Left, 18th Jan., 1890-Accepted, 19th Apr., 1890
PROVISIONAL SPECIFICATION.
Improvements in or relating to Pneumatic Guns,
A communication from HENRY EICHBAUM, of Hotel Burgundy, No. 8, Rue Duphot,
Paris, in the Republic of France, Engineer.
1, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
M.I.M.E., do hereby declare the nature of this invention to be as follows:-
The object of this invention is to produce a pneumatic gun in which the valve
which admits the pressure behind the projectile may always make its full stroke
notwithstanding that the pressure in the tubo is regulated according to the circum-
stances under which the projectile is to be delivered. Hitherto the amount of air
admitted into the gun tubo has been regulated by a greater or less amount of opening
allowed to the firing valve by delaying or accelerating its return to its seat; in the
present invention however it is intended that the valve may always open to its full
extent every time the gun is fired, the control of the air supply being accomplished
by regulating the area of the opening or openings through which the air enters the
gun tube.
It will be evident that various devices may be adopted for regulating these
openings through which the air enters the gun tube and I will describe now one
form of apparatus by which this may be successfully accomplished it being
understood that I do not limit myself to any one particular apparatus for this
purpose.
In the apparatus then which 1 am about to describe I provide the gun tube with
one or more openings, preferably a moderate number, so that they may be neither too
large nor too small, and preferably arranged at equal intervals around the tube.
These openings are covered by a sleeve also provided with corresponding openings
and which sleeve is so arranged that by any suitable mechanism as for example a
toothed segment and worm it may be revolved about the gun tube to the required
extent so as to open or close the openings in the gun tube. This sleeve may be
arranged in any convenient manner or position upon the gun tube and either inside
or out. Upon the sleeve already described and also upon a portion of the gun tube is
arranged a valve which preferably extends annularly entirely round this portion of
the gun to this valve may be imparted suitable longitudinal movement, and striking
buffers are provided. The valve is constructed to receive air pressure in both.
directions, that in the direction which would close it being by roason of the slightly
greater area provided at that end of the valve sufficiently in excess of the pressure at
the other end to keep the valve normally closed and also to promptly return it when
it has been opened. The regulation and adjustment of the air pressure upon this
valye and which is made at one end of it only, preferably towards the forward or
muzzle end of the gun, may be effected by any suitable means, say for example a
piston controlling valve with openings from the main air pressure to the valve and to
the atmosphere or exhaust.
The foregoing features may be disposed in or upon an annular valve casing adapted
to contain the air under pressure which has to be admitted to the gun. The action
would then be as follows:
--
The valve being normally closed, and as already explained, the pressure in the
casing tending to keep it closed, in order to open it the controlling valve is so moved
as to cut off from the forward end of the main valve the air pressure and establish a
connection between that end of the main valve and the atmosphere. The result of
this is that the air pressure upon the other end of the valve immediately forces it
open and retains it in that position until the controlling valve having been returned
to its normal position the air pressure is admitted to the forward end of the valve

page_text: which by reason of the difference in area promptly closes and remains closed until the
controlling valve is again operated.
The valves may be provided with any suitable form of packing to prevent leakage
past their working faces.
I have described the regulation of the area of the openings into the gun tube as
being effected by the sleeve to which movement around the gun is imparted, but it
will be manifest that with the same device the same effect could be obtained by
moving this. sleeve in a longitudinal direction; nevertheless as it is undesirable, to
impart to the sleeve movement in the same direction as is imparted to the main valve
I prefer to rotate the sleeve as previously described and to move the controlling valve
Fin a direction parallel to the axis of the gun.
Dated this 30th day of October 1889.
W. P. THOMPSON & BOULT,
Agents for the Applicant..
COMPLETE SPECIFICATION.
Improvements in or relating to Pneumatic Guns.
A communication from HENRY EICHBAUM, of Hotel Burgundy, No. 8 Rue Duplot,
Paris, in the Republic of France, Engineer.
I, ALFRED JULIUS BOULT of 323 High Holborn, in the County of Middlesex,
M.I.M.E., 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 subject of the present invention is improvements in or relating to pneumatic
guns in which the firing valve which admits the pressure behind the projectile may
always make its full stroke notwithstanding that the area or duration of the
admission opening is regulated according to the circumstances under which the
projectile is to be delivered, and in which the firing valve surrounds or encircles
the tube or barrel of the gun. Hitherto the amount of air admitted into the gun
tube has been regulated by a greater or less amount of opening allowed to the firing
valve by delaying or accelerating its return to its seat; in the present invention
however it is intended that the valve may always open to its full extent every time
the gun is fired, the control of the air supply being accomplished by regulating the
area of the opening or openings through which the air enters the gun tube.
It will be evident that various devices may be adopted for regulating these
openings through which the air enters the gun tube and I will now describe
cne form of apparatus by which this may be successfully accomplished it being
understood that I do not limit myself to any one particular apparatus for this
purpose.
"
Throughout this specification the word "firing" is employed to define the act
of discharging the projectile although in the gun constructed according to the
present invention there is no ignition of powder or other explosive; the word "air
is used to designate the compressed air or other gas which may be employed to
expel the projectile.
In the apparatus then which I am about to describe I provide the gun tube with
one or more openings, preferably a moderate number, so that they may be neither
too large nor too small, and preferably arranged at equal intervals around the tube.
These openings are covered by a sleeve also provided with corresponding openings
and which slcove is so arranged that by any suitable mechanism as for example a
toothed segment and worm it may be revolved about the gun tube to the required
extent so as to open or close the openings in the gun tube. This sleeve may be
arranged in any convenient manner or position upon the gun tube and either inside
or out. Upon the sleeve already described and also upon a portion of the gun tube is
arranged the firing valve which preferably extends annularly entirely around this
· portion of the gun; to this valve may be imparted suitable longitudinal movement,

page_text: and striking buffers are provided. The valve is constructed to receive air pressure
in both directions, that in the direction which would close it being by reason of the
greater area provided at that end of the valve sufficiently in excess of the pressure at
the other end to keep the valve normally closed and also to promptly return it to its
seat when it has been opened. The regulation and adjustment of the air pressure
upon this valve and which is made at one end of it only, preferably towards the
forward or muzzle end of the gun, may be effected by any suitable means, say for
example a piston controlling valve with openings from the main air pressure to the
valve and to the atmosphere or exhaust.
The foregoing features may be disposed in or upon an annular valve casing adapted
to contain the air under pressure which has to be admitted to the gun. The action
would then be as follows:-
The valve being normally closed, and as already explained the pressure in the
casing tending to keep it closed, in order to open it the controlling valve is so
moved as to cut off from the forward end of the main valve the air pressure and
establish a connection between that end of the main valve and the atmosphere. The
result of this is that the air pressure upon the other end of the valve immediately
forces it open and retains it in that position until the controlling valve having been
returned to its normal position the air pressure is admitted to the forward end of the
valve which by reason of the difference in area promptly closes and remains closed
until the controlling valve is again operated.
The valve may be provided with any suitable form of packing to prevent leakage
past their working faces.
1 havo described the regulation of the area of the openings into the gun tube as
being effected by the sleeve to which movement around the gun is imparted, but it
will be manifest that with the same device the same effect could be obtained by
moving this sleeve in a longitudinal direction: nevertheless I prefer to rotate the
sleeve as previously described and to move the firing valve in a direction parallel to
the axis of the gun. It is true that the sleeve might have longitudinal movement
imparted to it and the firing valve (having in this case openings instead of or in
addition to these in the sleeve) be caused to rotate; there are however practical
objections to this arrangement which is merely indicated here as an obvious alternative.
Where longitudinal movement was imparted to the sleeve the openings could be
dispensed with or retained according to circumstances.
に
In the accompanying drawings Figs. 1 and 2 are respectively a horizontal and a
vertical section of the rear or breech end of a pneumatic gun constructed according
to this invention Fig. 3 is a transverse section on the line a-b of fig. 2 and Fig. 4 is
a view of a detached portion of the apparatus.
Like letters indicate like parts throughout the drawings.
A is the gun tube or barrel and A¹ are openings formed in it at preferably equal
distances apart and of uniform size. B is the breech block which may be moved
horizontally in the guides B¹ in any convenient manner. C is the sleeve shown with
openings figs. 1 and 3 which when placed over them correspond in size and
position with the before mentioned openings A¹. C is a flange formed on the rear
end of C and at one part provided with the toothed sector C³ with which gears the
worm D, the shaft D' of which may be squared at one end D2 to admit of a key or
the like being placed on it. This shaft is supported in bracket bearings D³ figs. 1
and 4 secured in any convenient manner to a suitable stationary part of the gun such
as the ring or collar E. C fig. 4 is a scale marked on the sector C³ and F is an
index secured to a fixed part of the gun for indicating the extent to which the
openings A are uncovered by the sleeve C.
G is the firing valve which at its forward end surrounds and is capable of sliding
upon the gun barrel A and at its rear end slides upon the sleeve C from its closed
position in which it is shown in the lower part to the firing position in which it is
shown in the upper part of fig. 1 and vice versa. In fig. 2 the valve G is represented
as being moved from its firing to its closed position. g g' are shoulders or piston
surfaces formed on the exterior of the valve and the former of which is of greater
:

page_text: :
area than the latter'; g' is the end of the valve which is adapted to be pressed upon
the valve seat H a similar seat H' being provided so as to act as a buffer for the
other end. Jis preferably a casting in which is formed the valve casing or
cylinder J in which the valve G. is capable of moving longitudinally and by the
flange J of which it is secured to the flange A2 formed. upon or secured to the
barrel A. J3 are branches opening as shown in fig. 3 into the air belt J* which
together with said branches preferably forms part of the casting J. To the rear
flange Jof Jis secured the before mentioned ring or collar E between which and
the flange J the seating H may advantageously be secured in the manner shown in
figs. 1 and 2. The buffer His similarly retained in position between the flanges A?
and J. g3 are projections provided at suitable intervals apart on the outside of the
valve G to assist in guiding it at its forward end within the casing J¹.
·
K'fig. 1 are side pipes secured to the branches J³ for supplying the compressed
air or gas by which the gun is fired.
Je is a boss formed on the casting J and in which terminate the passages j and j
which respectively lead to the air belt J as shown in figs. 2 and 3 and to the
interior of the casing or cylinder J' as shown only in figure 2.
L is a casting secured upon the boss J its two ports joining and forming
continuations of the passages; and j' as shown in fig. 2. The casting L is hereinafter
referred to as 'the valve casing L. The interior of this casing L is bored out so that
its rear part 2 may be of larger diameter than the parts 13 and 1 which are of equal
'diameter. The parts 12 and are divided from each other by an annular recess or
belt into which opens the port and the parts 13 and 14 are similarly divided by a
belt into which opens the port . L' is a flanged collar screwed into the front
end of the valve casing I, so as to hold the buffer ring in position, and provided
with a central opening 18. L2 is the cover which closes-in the back end of the valve
casing L and is provided with a stop 1º. M. M¹ is a twin piston controlling valve the
part M of which accurately fits inside the short cylinder 12 and the part M¹ fits 1³
and . M is the rod which passes through the opening 18 and by which the
'controlling valve M M' may be moved when the gun is to be fired.
When the before described apparatus is in its normal condition and ready for firing
the valve M occupies in the casing L the position in which it is shown in fig. 2 so that
the compressed air has free access through the pipes K belt J4 passages and ports j, 1, 1,
and, to the piston face g upon which it acts and holds the firing valve G with its
edge g2 tightly against the seat H as shown in the lower part of fig. 1 and thus
prevents the air passing into the gun barrel A..
Assuming that when the position of the sleeve C leaves exposed some part of the
openings A it is desired to fire the gun, all that is necessary is to move the
valve M. M so that M¹ fits into the part of the casing by doing which the air
pressure is cut off from 9 which through j¹, 1, and 18 is then exposed only to the
atmospheric pressure and the compressed air acting on the piston face g¹ forces the
valve into the position shown in the upper part of fig. 1. The compressed air is
thus allowed to enter the gun barrel A through the openings C and A¹ to drive out
the projectile. The valve M M' being moved back to its original position as shown
in fig. 2 the compressed air again acting on the piston face g will return the valve G
to its seat Has illustrated in the lower part of fig. 1 and thus cut off.from the
barrel the supply of compressed air and will retain the said valve G in its closed
position until the valve M M is again operated. -
Instead of being operated by hand the valve M. M' may be moved by air pressure
controlled by another valve if desired; or other means may be employed for operating
the firing valve G.
•
By adjusting the position of the sleeve C on the barrel A by means of the
shaft D and worm gearing D C3 the extent of opening for the compressed air to be
admitted for firing the gun may be regulated or if desired it may be completely
closed; it will thus be seen that the firing valve G can always make a complete stroke
no matter what amount of air is to be admitted to the gun barrel.
The positions of the sleeve C and firing valve G may be transposed-the valve

page_text: inside and the sleeve outside-but the arrangement with the sleeve inside and valve
outside is preferred where the two are contiguous.
The valves G and M M if desired may be provided with any suitable form of
packing to prevent leakage past their working faces.
From the foregoing it will be seen that while hitherto the air pressure for
discharging the projectile has been introduced into the gun tube from a single point,
or according to a previous device of the present inventor from opposing points
governed by separate firing valves, in the present invention a single firing valve
extends completely around the gun tube and admits the air into it from all sides;;
thus securing an even or "balanced" admission of the pressure and the elimination.
of shocks or concussion in the working of the gun besides offering the least
obstruction to the flow of air into the barrel.
It will further be seen that instead of carrying the valve and sleeve entirely round
the gun they might be stopped off and extend say only one half or one quarter round,
the action of the parts relatively to each other being still the same; one objection to
such a formation however would be that the admission of the pressure would not be
balanced and concussion would probably ensue. Also by admitting the air all round
the tube in the manner described a very large area or series of areas can be
simultaneously and conveniently controlled. It will be seen that modifications may
be made in the apparatus without departure from the spirit of this invention; one
example would be the placing of the sleeve C inside the gun tube A instead of
outside it.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed as communicated to me by
my foreign correspondent I declare that what I claim is :-
1. In a pneumatic gun regulating the admission of the compressed air or gas
which expels the projectile without altering the extent or duration of the opening of
the firing valve or the pressure behind said valve.
2. In a pneumatic gun the employment of a firing valve encircling or surrounding
the tube substantially as described.
3. A pneumatic gun in which either a large or small a powerful or weak firing
charge can be admitted with the same travel of the firing valve.
4. In a pneumatic gun the combination with the barrel having openings such
as A¹ of a sleeve such as C adjustable in relation to such openings substantially as
and for the purpose herein described.
5. In a pneumatic gun the combination with the gun tube or barrel having
openings such as A¹ of a firing valve such as G operated in conjunction with such
openings to control the supply of compressed air to the gun substantially as hercin
described.
6. In a pneumatic gun the combination with the tube or barrel having openings
such as A and an adjustable sleeve such as C for regulating the effective area of
such openings, of a firing valve such as G substantially as herein described and
illustrated in the accompanying drawings.
7. In a pneumatic gun a firing valve such as G encircling the barrel and adapted
to cover and uncover openings such as A' in the tube or barrel substantially as herein
described and illustrated in the accompanying drawings.
8. In a pneumatic gun the arrangement and combination of parts constituting the
complete firing apparatus substantially as herein described and illustrated in the
accompanying drawings.
Dated this 18th day of January 1890.
W. P. THOMPSON & BOULT
Agents for the Applicant.