Improved Breech Closing Mechanism for Machine Guns.
Year: 1897

page_text: Date of Application, 11th May, 1897
Complete Specification Left, 10th Mar., 1898-Accepted, 16th Apr.,
1898
PROVISIONAL SPECIFICATION.
Improved Breech Closing Mechanism for Machine Guns.
I, ADOLF, BARON D'ODKOLEK, of Fichtenhof, near Klagenfurt, Carinthia, Austria,
Captain in the Imperial and Royal Army, retired, do hereby declare the nature of
this invention to be as follows:-
This invention relates to that class of breech closing mechanism for machine
guns in which a portion of the explosion gases produced on firing, are led off
through a lateral passage in the bore of the gun and are utilised for opening the
breech mechanism, a spring being at the same time put in compression which effects
the closing of the breech mechanism after firing.
The essential feature of the present invention consists in that the said explosion
gases are made to act directly upon the breech bolt by causing them to pass
through the said lateral passage of the bore into a channel or tube which leads them
into a hollow formed in the breech bolt, where they cause the bolt to turn upon
its head-end so as to become unlocked, whereupon it is pushed back by the gases,
while compressing the spring, to such an extent as to allow of the introduction of a
cartridge in any known manner usual with machine guns.
Figures 1 and 4 of the accompanying drawing shew longitudinal sections of two
arrangements of the breech mechanism for carrying out this invention, with the
breech bolt in the closed position, Figures 2 and 3 shew cross sections at -
and y-y of Figure 1.
The breech bolt A. butts with its rear end a against two cheeks 6 arranged later-
ally in the breech casing B and separated from each other by a longitudinal slot b¹.
The bolt has on its underside a projection a' which is either arranged near the rear
end of the breech bolt as at Figure 1, or, as at Figure 4, it extends as a rib along
the whole length of the breech bolt, and reaches down into a corresponding recess
in the breech casing.
The projection a³, which is of a width corresponding to that of the slot b', is
formed with an internal hollow or channel 2, which is enlarged downwards at the
mouth at the front end of the projection and communicates with the channel or
tube 63 which is connected to a lateral passage formed at a suitable point of the
bore of the gun, so that a portion of the explosion gases will pass back through 62
into the channel a².
The closed rear end a³ of this channel is formed so as to slant upward.
The projection a¹ bears against the head d of a spring D situated below the
guide cheeks b in the breech cap E. The breech casing B is somewhat enlarged
in a rearward and upward direction, so that the breech bolt A when in the closed
an axis passing
position, can swing upward in turning in a vertical plane on
through the centre of the cartridge base. The rear end of the breech bolt and the
supporting surfaces of the cheeks bare for this purpose formed with a curvature
whose centre coincides with that of the cartridge base.
The action of the breech mechanism is as follows:

page_text: On firing, a portion of the powder gases pass, as soon as the projectile has passed
beyond the lateral passage, into the channel 62 and thence into the channel a² of
the breech bolt, and in acting in the upward directed end a³ of this channel with
an upward blow against the projection a' they will cause the breech bolt to be
raised out of its supported or locked position.
++. 3
f. .T.
During such upward motion of the breech block the enlarged mouth of the
channel a² remains in communication with the channel 62, so that the gaseous
pressure still continues to act upon the breech bolt, and throws it backward in the
casing B, during which motion the spring D will be compressed by the projec-
tion a sliding in the slot b¹.
The gaseous pressure will now cease, and the breech bolt, which is in the open
position, will now be thrown forward again by the spring, which, as it acts excen-
trically to the head-end of the breech bolt, will press the projection a downward
and will consequently bring the bolt into the locked position again. As the breech
bolt closes, the loading and subsequent firing of a fresh cartridge is effected in any
manner usual with quick firing guns, whereupon the above described action is
repeated.
1007
ABEL & IMRAY,
Agents for the Applicant.
improved Breeen Cicsing Mechanism for Machine Guns.
I, ADOLF, BARON D'ODKOLEK, of Fichtenhof, near Klagenfurt, Carinthia, Austria,
Captain in the Imperial and Royal Army, retired, 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:-
I
This invention relates to that class of breech closing mechanism for machine
guns in which a portion of the explosion gases produced on firing, are led off
through a lateral passage in the bore of the gun and are utilised for opening the
breech mechanism, a spring being at the same time put in compression which effects
the closing of the breech mechanism after firing.
The essential feature of the present invention consists in that the said explosion
gases are made to act directly upon the breech bolt by causing" them to pass
through the said lateral passage of the bore into a channel or tube which leads them
into a hollow formed in the breech bolt, where they cause the bolt to turn' upon
its head-end so as to become unlocked whereupon it is pushed back by the gases,
while compressing the spring, to such an extent as to allow of the introduction of a
cartridge in any known manner usual with machine guns."
Figs. 1 and 4 of the drawing accompanying my Provisional Specification shew
longitudinal sections of two arrangements of the breech mechanism for carrying
out this invention, with the breech bolt in the closed position, Figs. 2 and 3 shew
cross sections at x and
У-у
of Fig. 1.
*1
.
> >
:
The breech bolt A butts with its rear end a against two cheeks b arranged later-
ally in the breech casing B. and separated from each other by a longitudinal slot b'.
The bolt has on its underside a projection a¹ which is either arranged near the rear
end of the breech bolt as at Fig. 1, or, as at Fig. 4, it extends as a rib along
the whole length of the breech bolt, and reaches down into a corresponding recess
in the breech casing.
The projection a¹, which is of a width corresponding to that of the slot b', is
formed with an internal hollow or channel a², which is enlarged downwards at the

page_text: mouth at the front end of the projection, and communicates with the channel or
tube which is connected to a lateral passage formed at a suitable point of the
bore of the gun, so that a portion of the explosion gases will pass back through b
into the channel a².
The closed rear end a³ of this channel is formed so as to slant upward.
The projection a bears against the head d of a spring D situated below the guide
cheeks b in the breech cap E.
The breech casing B is somewhat enlarged in a rearward and upward direction,
so that the breech bolt A when in the closed position, can swing upward in
turning in a vertical plane on an axis passing through the centre of the cartridge
base.
The rear end of the breech bolt and the supporting surfaces of the cheeks are
for this purpose formed with a curvature whose centre coincides with that of the
cartridge base.
The action of the breech mechanism is as follows:
On firing, a portion of the powder gases pass, as soon as the projectile has passed
beyond the lateral passage, into the channel 62 and thence into the channel a² of
the breech bolt, and in acting in the upward directed end a³ of this channel with
an upward blow against the projection a¹ they will cause the breech bolt to be
raised out of its supported or locked position.
During such upward motion of the breech block the enlarged mouth of the
channel a remains in communication with the channel 62, so that the gaseous
pressure still continues to act upon the breech bolt, and throws it backward in the
casing B, during which motion the spring D will be compressed by the projec-
tion a sliding in the slot b¹.
The gaseous pressure will now cease, and the breech bolt, which is in the open
position, will now be thrown forward again by the spring, which, as it acts excen-
trically to the head-end of the breech bolt, will press the projection a¹ downward
and will consequently bring the bolt into the locked position again. As the breech
bolt closes, the loading and subsequent firing of a fresh cartridge is effected in any
manner usual with machine guns, whereupon the above described action is
repeated.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, I declare that what I claim is:
1. A breech closing mechanism for machine guns wherein the gaseous pressure
taken from any point of the barrel is caused to act directly upon the breech bolt
so as to unlock it, push it back, and thereby open the breech, substantially as
described.
2. In breech closing mechanism operating as set forth in the first claim, pro-
viding the breech bolt A with a projection a' having a hollow a² which in the
closed position of the bolt communicates with the gas channel 62 branching from
the barrel, while the rear end a of the breech bolt bears against checks 6 of the
breech casing B, the breech block being raised over such cheeks by the action of
the gas pressure in the hollow a² on firing, thus first unlocking the breech bolt and
then pushing it backward, substantially as described.
Dated this 10th day of March 1898.
ABEL & IMRAY,
Agents for the Applicant.