Improvements in Breech Mechanism for Guns.
Year: 1887

page_text: PROVISIONAL SPECIFICATION.
Improvements in Breech Mechanism for Guns.
I THORSTEN NORrdenfelt of 53 Parliament Street, in the City of Westminsier,
Civil Engineer, de hereby declare the nature of this invention to be as
follows:-
My improvements relate to that class of breech mechanism in which the breech of
a gun is closed by a breech piece having segments of a screw thread on its sides to
lock into corresponding segments within the interior of the breech--so that to open
the breech the breech piece has first to have a partial turn given to it and then to be
drawn backwards.
According to my invention I by means of one turning movement of a lever handle
give to such a breech piece first a turning movement to disengage the screw threads
then a backward movement to draw it back clear of the breech and after-
wards carry it to one side to leave a clear opening into the breech end of the
borc.
One way in which this may be effected is as follows:-
Two lever arms or handles are formed to project from a ring which embraces and
can turn around the rear end of the breech piece.
To unclose the breech a partial turn, given to the ring by the lever arms extending
from it, turns the breech piece until the screw threads upon it no longer interlock with
the screw threads in the breech-the ring and breech piece being at this time locked
together by a radial sliding bolt. A further turning movement moves this bolt
endwise and unlocks the ring from the breech piece-a still farther movement causes
the breech piece to be drawn back. This is done by two arms which extend forwards
from the ends of the two lever arms along two opposite sides of the exterior of the
brecch end of the gun and which carry rollers that enter grooves formed in it. At
the time when the breech piece is to be drawn back the rollers come into parts of the
grooves which are inclined to the bore of the gun-and by the continued turning
of the ring the breech piece is consequently moved back-so soon as the breech
piece has been thus moved back clear of the breech the extremity of one of the arms
of the lever comes against and interlocks with a stud or stop and then the whole

page_text: lever consisting of the two lever arms and the ring turns around this stud as a
fulcrum and the ring carries the breech piece to one side and exposes the breech end
of the bore.
To close the breech the lever is turned in the opposite direction and the move-
ments are reversed.
When in opening the breech the breech piece is turned to disengage the screw
threads upon it from the screw threads in the breech it is caused to set back a hammer
or striker which is contained within the breech piece and also to move back an
extractor to extract the empty cartridge case from the bore. The setting back of the
hammer is effected in the following mauner:
The breech piece has a longitudinal central cavity formed into it from its rear end.
A pin attached to a link which is free to turn around and move endwise along the
stud above mentioned enters this cavity. The pin has within it a longitudinal
central striker or hammer which is pressed forwards by a coiled spring and
in rear of this hammer and in a line with it is a block which serves as a
trigger.
When the breech is turned an incline upon it acting upon a lug which projects
from the hammer stem forces the hammer back and then gives the hammer a partial
turn. A lug projecting from the hammer is thereby brought behind a stop
carried from the front end of the pin above mentioned and the hammer is held
back.
As the hammer goes back it presses back the trigger block. As the trigger is
moved back it has also a partial turn given to it by a pin standing out from the pin
on which the breech piece turns entering an inclined slot formed in it. When the
hammer and trigger block have been carried to the end of their backward movement a
slot formed in the front end of the trigger is by the trigger's turning movement
brought into such a position that the rear end of the hammer rod may pass into it.
When the hammer now has the partial turn given to it the trigger block being pressed
forward by a spring turns with it and passes on to the rear end of the hammer rod.
To release the hammer the trigger has to be pulled backwards it then turns the
hammer back in the opposite direction and sets it free from the stop which held it
back and the hammer is thrown forwards by its spring to fire the gun.
The extractor is made to slide to and fro in a longitudinal groove in the rear end of
the breech of the gun-it carries a tooth with which one of the screw threads on the
exterior of the breech piece is made to engage at the time when the breech piece is
turned to unlock it-it this way a slight backward movement is given to the
extractor and the cartridge case is started back. Afterwards as the breech piece is
drawn backwards the backward movement of the extractor is completed and when the
breech piece is turned aside it leaves the extractor and the empty cartridge case now
clear of the bore of the gun, can be lifted away by hand.
When a new cartridge is put into the breech the extractor may be pushed forward
with it.
The tooth is not fixed to the stein of the extractor but is free to slide a distance
along it. Normally it is pressed back by a spring until arrested by a stop on the
extractor stem but when the breech is being closed it is pressed forwards a distance
by the breech piece but is brought back again by the spring to its normal position so
soon as the breech piece has been turned to lock it into the breechi.
Dated this 16th day of December 1887.

page_text: 1, THORSTEN NORDENFELT of 53 Parliament Street, in the City of Westminster,
Civil 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:-
My improvements relate to that class of breech mechanism in which the breech of
a gun is closed by a breech piece having segments of a screw thread on its sides to
lock into corresponding segments within the interior of the breech-so that to open
the breech, the breech piece has first to have a partial turn given to it and then to be
drawn backwards.
According to my invention I by means of one turning movement of a lever handle
give to such a breech piece first a turning movement to disengage the screw threads
then a backward movement to draw it back clear of the breech and afterwards carry
it to one side to leave a clear opening into the breech end of the bore.
One way in which this may be effected is as follows:-
Two lever arms or handles are formed to project from a ring which embraces and
can turn around the rear end of the breech piece.
To unclose the breech a partial turn, given to the ring by the lever arms extending
from it, turns the breech piece until the screw threads upon it no longer interlock
with the screw threads in the breech-the ring and breech piece being at this time
locked together by a radial sliding-bolt. A further turning movement moves this bolt
endwise and unlocks the ring-from the breech piece-a still further movement causes
the breech piece to be drawn back. This is done by two arms which extend forwards
from the ends of the two lever arms along two opposite sides of the exterior of
the breech end of the gun and which carry rollers that enter grooves formed in
it. At the time when the breech piece is to be drawn back the rollers, come into
parts of the grooves which are inclined to the bore of the gun-and by the continued
turning of the ring the breech piece is consequently moved back--so soon as the
breech piece has been thus moved back clear of the breech the extremity of one of
the arms of the lever comes against and interlocks with a stud or stop and then the
whole lever consisting of the two lever arms and the ring turns around this stud as a
fulcrum and the ring carries the breech piece to one side and exposes the breech end
of the bore.
To close the breech the lever is turned in the opposite direction and the movements
are reversed.
When in opening the breech the breech piece is turned to disengage the screw
threads upon it from the screw threads in the breech it is caused to set back a hammer
or striker which is contained within the breech piece and also to move back an
extractor to extract the empty cartridge case from the bore. The setting back of the
hammer is effected in the following manner :-
The breech piece has a longitudinal central cavity formed in it from its rear end.
A pin attached to a link which is free to turn around and move endwise along the

page_text: stud above mentioned enters this cavity. The pin has within it a longitudinal central
striker or hammer which is pressed forwards by a coiled spring and in rear of this
hammer and in a line with it is a block which serves as a trigger.
When the breech piece is turned preparatory to opening the breech an incline upon
it acting upon a lug which projects from the hammer stem forces the hammer
back.
When the
As the hammer goes back it presses back the trigger block. As the trigger block
is moved back it has also a partial turn given to it by a pin standing out from the pin
on which the breech piece turns entering an inclined slot formed in it.
hammer and trigger block have been carried to the end of their backward movement
a slot formed in the front end of the trigger is by the trigger's turning movement
brought into such a position that the rear end of the hammer rod may pass into it.
The trigger block now being pressed forward by its spring passes on to the rear end
of the hammer rod and turning as it advances it also turns the hammer and brings the
projection upon it in rear of a stop or shoulder in the side of the recess in which the
hammer works. The hammer is then cocked. To release the hammer the trigger has
to be pulled backwards it then turns the hammer back in the opposite direction and
sets it free from the stop or shoulder which held it back and the hammer is thrown
forwards by its spring to fire the gun.
The extractor is made to slide to and fro in a longitudinal groove in the rear end of
the breech of the gun it carries a tooth with which one of the screw threads on the
exterior of the breech piece is made to engage at the time when the breech piece is
turned to unlock it-in this way a slight backward movement is given to the
extractor and the cartridge case is started back. Afterwards as the breech piece is
drawn backwards the backward movement of the extractor is completed and when the
breech piece is turned aside it leaves the extractor and the empty cartridge case
now clear of the bore of the gun can be lifted away by hand.
When a new cartridge is put into the breech the extractor may be pushed forward
with it.
The tooth is not fixed to the stem of the extractor but is free to slide a distance
along it. Normally it is pressed back by a spring until arrested by a stop on the
extractor stem but when the breech is being closed it is pressed forwards a
distance by the breech piece but is brought back again by the spring to its
normal position so soon as the breech piece has been turned to lock it into the
breech.
In order that my said invention may be fully understood and readily carried into
effect I will proceed to describe the drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 of the drawings annexed is a longitudinal section of the mechanism taken
through the line R S T U V Figure 2.
Figure 2 is a view from the rear with the breech closed and locked and
Figure 3 is a view from the rear with the breech open ready to receive a fresh
cartridge.
Figures 4 to 9 shew details.
a is the screw breech piece b is a ring capable of turning around its rear end.
6 are radial arms extending from the ring and provided with handles 62 by which the
ring
be turned
dial halt by which the carow and ring are at times

page_text: of
lines in Figure 1 made inclined to the bore. is a hollow pin upon which the breech
piece a turns it is fixed to an army which can turn upon and also slide back along
a fixed stud which projects from the rear end of the gun. The rear extremity
the stud is made to the form of a segment of a ring concentric with the stud. 66 is a
groove in the front face of one of the radial arms which passes on to and embraces
this segment end after the screw breech piece has been unlocked and drawn back. So
soon as the groove 6 engages with the annular segment h¹ the ring b turns around
the stud h until the screw breech piece a is supported by the stop which stands out
from the rear end of the breech of the gun the parts are then in the position shown in
Figure 3.
When opening the breech the screw a and ring bare at first locked together by the
radial bolt as the inner end of the bolt then abuts against the pin or axis f
consequently when the ring is turned both the ring and the screw turn together until
the inner end of the bolte comes opposite to and is made to enter a recess in the axisf
and is thereby disengaged from the ring leaving the ring free to continue turning
without turning the screw. The pin in the breech block is then at the end of the
slot which receives it in the armg.
The endway movement is given to the bolt by a pin e' upon it which enters the
inclined end of a slot in the ring.
The incline of the slot is therefore always tending to press the bolt inwards.
As the ring continues its turning movement the rollers d' at the extremity of the
arms d now enter the parts of the groove e which are inclined to the central line of
the bore and the screw breech block is drawn back until the rollers come into the
end portions of the grooves which are not inclined.
The radial arm & then engages with the stud and the ring with its arms band
the arm g all turn around the stud has a fulcrum, and the breech screw is carried to
one side of the rear end of the breech and left resting upon the support j. When the
lever is turned back in the opposite direction the movements are reversed and the
breech is closed.
The lock mechanism is contained within the pin f on which the breech screw a
turns.
The arrangements for setting back the hammer or striker to its "cocked" position
are as follows:
kis the hammer or striker it is shown separately by the Figures 4. it is thrown
forward by the spring . is the trigger in a line with and in rear of the hammer.
The trigger is shown separately by the Figures 5. this trigger is also pressed forward
by a spring
The hammer and the trigger are contained within the hollow axis which is shown
separately by the Figures 6. When the trigger moves to and fro it has also a partial
rotation given to it by a pin 2 fixed to the axis fentering an inclined groove formed
in the trigger. In the front end of the trigger is a recess into which the rear end
of the stem of the striker enters when it is brought into a line with it.
When a turning movement is given to the breech screw to unlock it an incline on
the breech screw acting upon a lug 2 projecting from the hammer, forces the hammer
back. As the hammer is being pressed back it presses back the trigger also and as
the trigger is moved back it also has a partial turn given to it in the manner above
mentioned and at the end of its backward movement the slot in its front end is
brought into such a position that the rear end of the stem of the hammer can enter
into it. The trigger then is pressed forward by its spring and the hammer has a
partial turn given to it. A lug projecting from the hammer is thereby brought in
rear of a stop m carried by the axis fand the hammer is held back.
To release the hammer the trigger block has to be pulled backwards by a cord.
When drawn back it turns the hammer in the opposite direction to that above men-
tioned and so sets it free to be thrown forwards by its spring.
n is the extractor it is shown separately by the Figures 7. The extractor slides in a
longitudinal groove in the rear end of the gun it carries a tooth n¹ shown separately
by the Figures & with which one of the screw threads of the breech screw engages

page_text: when the breech screw is turned. When the screw is turned to open the breech a
slight backward movement is thereby given to the extractor, and the empty cartridge
case is started back from the rear end of the bore of the gun.. When the breech
screw is drawn back the extractor carries the cartridge case backwards along with it.
When at the end of the backward movement of the breech screw, the breech screw
is turned to one side, the threads of the screw become disengaged from the tootli n¹
of the extractor.
When a new cartridge is placed into the gun its flange carries the extractor forwards
along with it. When the breech screw is moved forwards to close the breech and
has a partial turn given to it the cartridge and extractor are pressed home.
Also as
the breech screw advances the screw thread comes against the tooth n' of the extractor
and presses it forwards. In order that it may at this time be free to move forwards,
the tooth is carried by a small slide n² which is free to move to and fro along the
extractor stem but is pressed backwards by a spring n³. These parts are shown col-
lectively in Figure 9. When the screw has been turned to its locked position the
screw thread becomes disengaged from the tooth n¹ and the spring presses the
slide 2 back so that when the breech screw is again turned to open the breech
the tooth is found in proper position to be engaged by it.
Having now particularly described and ascertained the nature of my said invention
and in what manner the same is to be performed I declare that what. I claim is :—
1. Constructing breech mechanism for guns having a breech block with divided
segments of screw threads in such a manner that by one turning movement of a
suitable handle or part the breech screw is turned far enough to unlock it and then
drawn back to free it from the breech of the gun and then turned aside by movement
around an axis parallel to the bore of the gun, thereby to leave the rear end of the
breech open to receive the charge.
2. Constructing breech mechanism for guns having a breech block with divided
segments of screw threads in such a manner that in opening the breech the said block
after it has been turned to disengage the screw and drawn back to free it from
the breech of the gun, is then moved about an axis parallel to the bore of the gun to
carry it to one side and leave the breech open to receive the charge.
3. Mechanism for operating the said breech screw and for carrying it rearwards
when it has been unlocked, and consisting of an inclined groove on the exterior of
the gun in which works a stud or roller on an arm connected with the breech block
which by continuing the turning movement in the same direction as was used for
unlocking the breech block travels back along the inclined groove taking the breech
block with it.
4. The combination of mechanism shown in the drawings hereto annexed for giving
movement to the breech block.
5. The combination of mechanism substantially as described for setting the hammer
and retaining it in its cocked position as the breech is opened and releasing it when
the shot is to be fired.
6. The extractor having a tooth which engages with the thread on the breech screw,
whereby the extractor is moved longitudinally with the same.
7. The combination in connection with the extractor of mechanism substantially as
described whereby the tooth of the extractor is permitted to yield to the screw of
the breech block when closing the breech but afterwards returns into position to
commence to draw back the cartridge case as soon as the screw breech piece com-
mences to turn to open the breech.
Dated this 10th day of September 1888.