Improvements in and relating to Automatic Guns.
Year: 1894

page_text: Date of Application, 27th Oct., 1894
Complete Specification Left, 27th July, 1895-Accepted, 21st Sept., 1895
PROVISIONAL SPECIFICATION.
Improvements in and relating to Automatic Guns.
I, HIRAM STEVENS MAXIM, of Baldwyn's Park, Bexley, in the County
of Kent, Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention relates to automatic or "Maxim" guns and is designed to adapt
the same to work more efficiently than heretofore with the cartridges now commonly
used in fire arms, that is to say, cartridges charged with smokeless powder and
light projectiles.
The said invention is also designed to provide for controlling the speed of firing
such guns.
"
It has been found that with cartridges such as those above referred to the recoil
energy is in some instances too feeble to satisfactorily operate the breech-niechanism
of a Maxim gun. I have therefore provided for increasing the energy of the
recoil movement in such a manner that any form or arrangement of the automatic
mechanism can be efficiently operated thereby.
For this purpose 1 place on the muzzle end of the barrel a short cylinder which
is secured to the end of the frame or casing of the gun. The muzzle end of the
barrel is reduced in diameter so as to form a shoulder thereon and the reduced end
is fitted to slide through the fore end of the said cylinder. I cut through the
reduced end of the barrel a series of holes or slots which extend from the bottom
of the grooves of the rifling into the annular space surrounding the barrel in the
said cylinder. Therefore when the gun is fired the barrel first moves backward or
recoils by reason of the inertia of the projectile therein and. then has its action
increased as the projectile passes forward beyond the said apertures and allows the
high pressure gases in the barrel to enter the said chamber and add to the recoil
energy their pressure on the end of the barrel,
The above described contrivance is in some instances modified by forming in the
wall of the chamber an annular groove or channel surrounding the part of the
barrel to the rear of the shoulder, the wall of the chamber enclosing this groove
having apertures communicating with the external atmosphere. The said groove is
in such a position that in the commencement of the recoil the shoulder of the barrel
moves back such a distance that the aforesaid holes or slots in the barrel come
within the said annular groove or channel so that the gas which enters the chamber
through the said holes or slots and which acts on the end of the barrel to avoid
the recoil will escape into the atmosphere through the apertures in the wall of the
chamber.
By varying the diameter of the barrel, the area of the shoulder, the dimensions
of the cylinder or chamber, or the number and size of the slots or apertures the
apparatus may be modified according to the amount of energy required for the
efficient and satisfactory operation of the gun.
The rapidity of fire of a Maxim gun is usually very high and it is now considered
desirable in some instances to diminish such rapidity. For this purpose employ
the following apparatus, that is to say, referring to guns in which there is a crank
handle arranged in combination with a buffer spring which by its reaction after
being struck by the crank causes the latter to instantly rebound and return the
crank to its firing position, I now replace this buffer spring with a device which
.

page_text: stops the crank handle without reacting to cause its rebound. This device is a
spring catch arranged at the side of the gun frame in combination with the crank
handle. The said catch may be itself a spring or it may be a pivotted arm pressed
into its proper position by a separate spring. The free end of the said catch or
arm is formed with an incline so arranged relatively to a point or projection on the
crank handle that when the latter strikes the said incline the catch is moved
outward the handle having then passed below the said catch. By its outward
movement a projection on the catch is brought into a position to engage with a
second point or projection on the crank handle thereby preventing its return until
after the barrel has returned to the firing position, and then it is thrown back by
the fusee spring of the crank shaft which being a light spring does not cause a
violent or rapid action of the crank.
By working the gun with this comparatively slow movement I obtain a more
advantageous cooling effect of the water in the water jacket than when the gun is
working with great rapidity and making steam so fast that the steam and water are
blown out together. Moreover as the intervals of time between the shots are
lengthened the heat has more time to diffuse itself through the barrel and to be
dissipated in the surrounding water.
By my invention I avail myself of so much of the energy of the recoil that I ain
enabled to make the parts of the mechanism much heavier and stronger than
heretofore and therefore better adapted to the use of charges of smokeless
powder.
The said invention also insures the synchronism of the action of the lock and
of the barrel.
improvements in and relating to Automatic Guns.
...
I, HIRAM STEVENS MAXIM, of Baldwyn's Park, Bexley, in the County of
Kent, 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 automatic or "Maxim" guns and has for one of its
objects to adapt the same to work more efficiently than heretofore with the
cartridges now commonly used in fire-arms, that is to say, cartridges charged with
smokeless powder and light projectiles.
11
The said invention is also designed to provide for controlling the speed of firing
such guns.
It has been found that with cartridges such as those above referred to the recoil
energy is in some instances too feeble to satisfactorily operate the breech-mechanism,
I have therefore provided improved means whereby the energy of the recoil move-
ment can be increased in such a manner that any form or arrangement of the
automatic mechanism can be efficiently operated thereby.
It has also been found by recent experiments in fire-arms that the accuracy of
fire can be considerably increased if the pressure at the instant the projectile leaves
the barrel is somewhat low with relation to the initial pressure. With a slow
burning powder in which a low initial, but a high mean, pressure is maintained
throughout the entire length of the barrel it has been found that the great pressure
on the base of the projectile and the escape of gas radially between the barrel and
the projectile at the instant the latter is leaving the barrel often causes the

page_text: projectile to be thrown slightly out of line and the accuracy of fire is consequently
interfered with to a serious extent. With a powder in which the greater part of
the work is done with a high initial pressure and a relatively low final pressure the
accuracy of fire is not interfered with to such a serious extent. By my present
invention the means I employ for increasing the recoil of the barrel also enables a
portion of the gases immediately behind the projectile to escape just before the
latter leaves the barrel, the said gases escaping while the projectile is still engaged
with the rifling. In this manner the pressure is reduced sufficiently to admit of:
much more accurate firing than has been heretofore practicable.
In the accompanying drawings I have shewn an advantageous manner of carrying
niy invention into effect,
Figure 1 being a longitudinal section of the muzzle of the gun and Figure 2 an
end elevation thereof.
Figures 3 and 4 are enlarged views shewing respectively a longitudinal section
and a transverse section (the latter being taken on the line ww of Figure 3) of the
muzzle end of the barrel..
Figures 5 to 8 illustrate the device for reducing the speed of firing the gun;
Figure 5 being a side elevation of the rear portion of the gun and Figure 6 an
edge view of the spring catch hereinafter referred to.
Figure 7 is a similar view to Figure 6 but shews the spring catch in another
position.
Figure 8 is a fragmentary view shewing a modified construction of the upper
portion of the spring catch."
:
Referring more particularly to Figures 1 to 4 the barrel a is according to my.
present invention prolonged so that its muzzle projects through the front end of the
gas cylinder and said barrel is enlarged at a and formed with a reduced
portion a whereby a shoulder is produced at a. Immediately in front of this
shoulder I cut a series of radial apertures a at which extend from the bottom of
the grooves of the rifling (as best seen in Figures 3 and 4) and communicate with
a cavity or chamber 6' produced by the short cylinder 6 surrounding the enlarged
portion a' of the barrel, said cylinder being screwed or otherwise connected to the-
framing or water jacket c of the gun. This surrounding cylinder is provided with
an orifice a* at its front end through which the reduced portion a² of the barrel'
projects when said barrel is in its firing position. An annular cavity or groove b
having exit apertures 6 63 communicating with the atmosphere, is formed in the
walls of the said cylinder and extends around the enlarged portion of the barrel in
rear of the shoulder a*.
When the gun is fired the barrel first moves backward or recoils by reason of the
inertia of the projectile therein. This action is still further increased, as the
projectile passes forward beyond the apertures at, by the high pressure gases in
the barrel entering the cavity or chamber 61 and acting upon the shoulder a³,
thereby assisting the recoil movement by forcing back the barrel. At the same time.
the pressure of the gases immediately behind the projectile, is reduced just before
said projectile leaves the barrel, and in this mauner the inaccuracy of firing
hereinbefore alluded to avoided. As soon as the shoulder recedes far enough to
enter the annular cavity or groove the gases are at liberty to escape into the
atmosphere through the apertures b³.
The muzzle end a² of the barrel may be made of such a length that on the firing.
of the gun the muzzle will be fully retracted into the chamber b¹ so as to leave a
space communicating with the atmosphere between said muzzle and the orifice a*,"
through which the gases can escape. In this manner the annular cavity or
groove and the apertures & leading therefrom can be dispensed with.
It will be seen that by reason of the radial apertures a extending outwardly
from the bottom of the grooves of the rifling, they do not in any way interfere
with the moving projectile, as it is well known that when the projectile is near the
muzzle of the barrel it never touches the bottom of the grooves but only rests on
the "lands."

page_text: By varying the diameter of the barrel; the area of the shoulder a³; the
dimensions of the cylinder b; or the number and size of the apertures, the
apparatus can be modified according to the amount of energy required for
the efficient and satisfactory operation of the breech mechanism.
The rapidity of fire of a "Maxim" gun is usually very high andrit, is now
considered desirable in some instances to diminish such. rapidity. For this purpose
the buffer-spring employed for causing the erank-handle or arm to instantly rebound
and return to its firing position, after each discharge, is by, my present invention
dispensed with and in place thereof I employ a device which stops the crank-handle
without reacting to cause its rebound.
This device illustrated at Figures 5 to 8 and comprises a spring-catch d which
is arranged at the side of the gun-frame or casing. A so as to act in conjunction
with a projection or stud e¹ on the crank handle or arm e, said catch consisting of
a suitably shaped spring as shewn, or of a similarly shaped metal blade controlled
by a spring. The lower end of the catch is adapted to fit into a socket A' secured
to the frame or casing A while its upper end is free and is formed with an inclined
portion d¹ (Figures 6 and 7) and a recess.d. As shewn at Figures 6 and 7 the
lower outer edge d* of this recess is made to project forward beyond the upper
edge and has its inner surface d** bevelled, while the lower surface of the before
mentioned projection or stud e' on the crank, handle is correspondingly bevelled.
The inclined portion d¹ and recess d are so arranged relatively to the projection
or stud e on the crank-handle that when said projection strikes the said incline d'
the catch is caused by its resilience to give way to the projection (see Figure 7) and
allow it to enter the recess d, and its bevelled surface to immediately engage with
the bevelled surface d** of the recess. The spring catch is thus caused to promptly.
resume its normal position. I thus ensure that the upper edge of the recess shall
be stopped directly over the projection e¹ before the crank-handle has. time to
rebound. In this way I avoid any chance of the said projection accidentally
escaping from the recess.
The crank-handle, now occupies the position shewn by the dotted lines e* in
Figure 5 having followed the course represented approximately by the curved
line x.
When in this position the crank-handle is prevented from returning again
until after the barrel has regained its firing position, that is, to say, until after the:
said projection e' has escaped from the forward end of the recess d', (as shewn by
the dotted lines exx in Figure 5). The crank-handle is then free to be thrown
back in the direction of the curved line y by the fusee-spring which latter
being a light one does not cause a violent or rapid action of the crank-handle.
Instead of arranging the recess d' horizontally, as shewn at Figure 5 it may be
arranged at an inclination as illustrated at Figure 8 and the speed of firing be
thereby still, further reduced.
By working the gun with this comparatively slow movement I. obtain a more
advantageous cooling effect of the water-jacket than when the gun is working with
great rapidity and making steam so fast that the steam and water are blown out
together. Moreover as the intervals of time between the shots, are lengthened the
heat has more time to diffuse itself through the barrel, and to be dissipated in the
surrounding water.
By this invention I can avail myself of so much of the energy of the recoil
that I am enabled to make the parts of the mechanism much heavier and stronger
than, heretofore and thereby much better adapted to the use of charges of smokeless
powder.
The said invention also ensures the synchronism of the action of the lock and
of the barrel.
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. The means for increasing the recoil energy of an automatic gun consistino of a

page_text: barrel having a shoulder and extending completely through a surrounding gas.
cylinder, a series of radial apertures situated immediately in front of the shoulder,
and a space or chamber within the gas cylinder into which the gases enter through
the aforesaid radial apertures and from which they escape into the atmosphere by
forcing back the barrel substantially as described.
2. In an automatic gun the means or apparatus for increasing the recoil energy
substantially as described with reference to Figures 1 to 4 of the accompanying
drawings and for the purpose specified.
3. In an automatic gun a barrel provided with a series of radial apertures
leading from the bottom of the grooves to the external part of the barrel for the
purpose specified.
4. The means for controlling the speed of firing automatic gun consisting of a
spring catch with which a projection on the crank-handle engages at each discharge
and remains in engagement therewith until released by the movement of the barrel
in regaining its firing position, substantially as described.
•
5. In an automatic gun of the class hereinbefore referred to the means or device
for controlling the speed of firing substantially as described with reference to
Figures 5 to 7 or to Figure 8 of the accompanying drawings.
T11005
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.