Year: 1888

page_text: I, THORSTEN NORDENFELT of 53 Parliament Street in the City of Westminster
Civil Engineer do hereby declare the nature of this invention to be as follows:--
My improvements relate to breech mechanism formed as described in a Provisional
Specification lodged by me on the 16th day of December No. 17351 in the year 1887
in such a manner that a screw breech piece formed with divided segments of screw
threads has first given to it a turning movement to unlock it is then drawn back
and is afterwards carried away to one side by one turning movement of a lever
handle which forms a part of the moveable breech piece.
I now give these movements to the screw breech piece in the following manner.
I form the rear end of the screw breech piece to extend backwards beyond the
breech end of the gun and to enter and be free to turn in what I call a carrier
ring. This carrier ring at one side near its lower part can be turned around a
pin which projects backwards from the rear end of the breech of the gun.
The front end of the carrier ring bas another ring surrounding and free to turn upon
it and this outer ring has a lever arm extending from it.
The ring has also a pin projecting inwards from it-it passes through a slot in
the carrier ring and into a helicoidal groove formed in the side of the screw breech
piece.
When the outer ring has a partial turn given to it from left to right to unlock the
breech screw the pin is at the commencement of the movement at one end of the
helicoidal groove and when the ring is turned tends either to turn the screw or to
draw it back but as the screw threads restrain it from being drawn back it can
only turn and is turned until the screw segments upon its sides are disengaged from
the corresponding screw segments on the sides of the bore of the gun.
A pro-
jecting lug on the stem of the breech screw then comes against a stop on the inside
of the carrier ring which prevents it from turning further. Therefore as the outer
ring continues to be turned the screw breech piece being now free to be drawn
back is drawn back by the pin above mentioned working along the helicoidal groove.
As the screw is drawn back the lug above mentioned which keeps it from turning
slides back along a groove formed in the carrier ring. The interior surface of the
гр.

page_text: carrier ring is also cut away in segments and as the screw is drawn back the
segments of screw threads which project from it pass into these segment recesses
in the ring and keep the screw from turning after the lug above mentioned has by
the backward movement of the screw breech piece been carried back beyond the
rear end of the carrier ring.
When the pin arrives at the end of the helicoidal groove in the screw and the screw
consequently cannot be drawn back any further its front end has been drawn back
from the bore of the gun-the extractor which it draws back with it has also been
withdrawn so that as the movement of the handle is continued the carrier ring and
parts carried within it being now no longer restrained from being turned to one
side are turned around the pin by which the ring is pivotted to the breech end of
the gun until further movement is arrested by an arm on the ring coming against
a stop on the breech.
The extractor is formed of a block capable of being slidden to and fro along one of
the non threaded segments in the breech end of the gun which is hollowed out to
receive it and also of being slidden hack into a longitudinal groove formed on the
inside of the carrier ring. At its front end it has a claw to engage with the rim
of the cartridge and on its inside two or three teeth to engage with some of the screw
threads of the screw breech piece. As the screw breech piece is turned to unlock
it the screw threads acting on the teeth move the extractor back a short distance
and draw the cartridge back along with it.
As the screw is drawn backwards the extractor and cartridge are also drawn along
with it.
When the screw has been drawn back to the end of its backward movement and the
extractor has been thereby drawn back into the carrier ring the extractor is carried
away together with the breechblock by the carrier ring when the carrier ring is
turned to one side-at the same time a stop plate on the axis of this ring is by the
turning movement carried into a position to come in front of the rim of the cartridge
case and prevents it again moving forwards. Similarly when the cartridge case bas
been removed and a new cartridge inserted instead of it the flange of the new cartridge
comes against this stop plate and is so arrested in proper position for the front end of
the breech screw to come into position in rear of it.
As the breech screw is brought behind the rear end of the new cartridge the
extractor is carried along with it and the claw at its front end comes in front of the
flange which is around the base of the cartridge so that when the screw is moved
forwards to close the breech it pushes the cartridge and extractor along with it.
The edge of the carrier ring which first comes against the rear end of the cartridge
case may he somewhat bevelled off so that should the cartridge have started back
from or not have been pushed home to the stop plate above mentioned it will push
forward the cartridge and bring it to its proper position to enable the breech screw
to be brought behind it.
The closing of the breech is effected by a continued movement of the lever handle
in the opposite direction to that in which it is moved for opening.
Dated this 21st day of February 1888

page_text: I 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 breech mechanism formed as described in a Provisional
Specification lodged by me on the 16th day of December No. 17351 in the year 1887
in such a manner that a screw. breech piece formed with divided segments of screw
threads has first given to it a turning movement to unlock it is then drawn back
and is afterwards carried away to one side by one turning movement of a lever handle
which forms a part of the moveable breech piece.
I now give these movements to the screw breech piece in the following manner.
I form the rear end of the screw breech piece to extend backwards beyond the
breech end of the gun and to enter and be free to turn in what I call a carrier ring.
This carrier ring at one side near its lower part can be turned around a pin which
projects backwards from the rear end of the breech of the gun.
The front end of the carrier ring has another ring surrounding and free to turn
upon it and this outer ring has a lever arm extending from it.
The ring has also a pin projecting inwards from it, it passes through a slot
in the carrier ring and into a helicoidal groove formed in the side of the screw breech
piece.
When the outer ring has a partial turn given to it to unlock the breech screw the pin
is at the commencement of the movement at one end of the helicoidal groove and when
the ring is turned tends either to turn the screw or to draw it back but as the screw
threads restrain it from being drawn back it can only turn and is turned until the screw
segments upon its sides are disengaged from the corresponding screw segments on
the sides of the bore of the gun. A projecting lug on the stem of the breech screw
then comes against a stop on the inside of the carrier ring which prevents it from
turning further. Therefore as the outer ring continues to be turned the screw breech
piece being now free to be drawn back is drawn back by the pin above mentioned
working along the helicoidal groove. As the screw is drawn back the lug above
mentioned which keeps it from turning slides back along a groove formed in the
carrier ring. The interior surface of the carrier ring is also cut away in segments and
as the screw is drawn back the segments of screw threads which project from it pass
into these segment recesses in the ring and keep the screw from turning after the lug
above mentioned has by the backward movement of the screw breech piece been
carried back beyond the rear end of the carrier ring.
When the pin arrives at the end of the helicoidal groove in the screw and the
screw consequently cannot be drawn back any further its front end has been drawn
back from the bore of the gun-the extractor which it draws back with it has also
been withdrawn so that as the movement of the handle is continued the carrier ring

page_text: and parts carried within it being now no longer restrained from being turned to one
side are turned around the pin by which the ring is pivotted to the breech end of
the gun until further movement is arrested by an arm on the ring coming against a
stop on the breech.
The extractor is formed of a block capable of being slidden to and fro along one
of the non threaded segments in the breech end of the gun which is hollowed out
to receive it and also of being slidden back into a longitudinal groove formed on
the inside of the carrier ring. At its front end it has a claw to engage with the
rim of the cartridge-and on its inside two or three teeth to engage with some of
the screw threads of the screw breech piece. As the screw breech piece is turned
to unlock it the screw threads acting on the teeth move the extractor back a short
distance and draw the cartridge back along with it.
As the screw is drawn backwards the extractor and cartridge are also drawn along
with it.
When the screw has been drawn back to the end of its backward movement and
the extractor has been thereby drawn back into the carrier ring the extractor is
carried away together with the breech block by the carrier ring when the carrier
ring is turned to one side-at the same time a stop plate on the axis of this ring
is by the turning movement carried into a position to come in front of the rim of
the cartridge case and prevents it again moving forwards. Similarly when the
cartridge case has been removed and a new cartridge inserted instead of it the
flange of the new cartridge comes against this stop plate and is so arrested in
proper position for the front end of the breech screw to come into position in
rear of it.
As the breech screw is brought behind the rear end of the new cartridge the
extractor is carried along with it and the claw at its front end comes in front of
the flange which is around the base of the cartridge so that when the screw is
moved forwards to close the breech it pushes the cartridge and extractor along
with it.
The edge of the carrier ring which first comes against the rear end of the cartridge
case may be somewhat bevelled off so that should the cartridge have started back
from or not have been pushed home to the stop plate above mentioned it will push
forward the cartridge and bring it to its proper position to enable the breech screw
to be brought behind it.
The closing of the breech is effected by a continued movement of the lever handle
in the opposite direction to that in which it is moved for opening.
In order that ny 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 2 is a longi
Figure 1 is a back view of the gun with the breech closed.
tudinal section on the line A, B figure 1. Figure 3 is a cross section on the line E F
of Figure 4 after the second part of the opening movement. Figure 4 is a longi-
tudinal section on the line C D of Figure 3-Figure 5 is a back view of the gun with
the breech open and Figure 6 is a section on the line a bc of Figure 5.
A is a screw breech piece A¹ the segments of screw thread on its sides to lock
into corresponding screw segments in the breech end of the gun. The breech piece A.
extends backwards beyond the rear end of the gun and enters loosely into a carrier
ring B. This ring has a short arm extending from it and a boss B₁ at the end of the
arm can be turned about a pin C which projects backwards from the rear end of the
breech of the gun-D is a ring embracing and free to turn around the front end of
the carrier ring-D₁ is a lever handle extending from the ring D by which the ring
can be turned D is a pin projecting inwards from the ring and passing through a
slot B2 in the carrier ring into a helicoidal groove A' in the screw breech piece A-
A is a lug projecting from the screw breech piece-it enters a slot cut out from the
front end of the carrier ring and serves as a stop to prevent the breech piece being turned

page_text: in
too far it can also be drawn backwards along a longitudinal slot B3 on the inside of the
carrier ring when the screw breech piece has been turned into a position to unlock it
from the screw segments in the gun. The interior of the carrier ring is cut away
segments corresponding to the screw segments of the breech piece so that when the
breech piece has been unlocked it may be drawn backwards into it.
B is an arm
extending from the boss B¹ of the arin which carries the carrier ring. When the
boss is turned around the pin it comes against a fixed projection E on the breech
end of the gun and the extent to which it can be turned is thereby limited. B' is a
stop plate fixed to the front end of the boss B' and which when the breech piece has
been drawn back and an empty cartridge case with it comes in front of the flange of
the cartridge as soon as the carrier is turned to one side and prevents the empty
cartridge case from being pushed back into the gun. The extractor is formed of a
slide having a hook at its front end to book over the rim at the rear end of the
cartridge case and capable of being moved along a slot G in the gun which is a
deepening of one of the grooves cut away between the segments of screw threads
in the gun.
On the inner face of the slide are teeth to engage with the screw threads on the
screw breech piece.
The action of the mechanism is as follows:-
To open the breech the ring D has a partial turn given to it by its lever handle D'
the pin D which is then at one end of the helicoidal groove A² tends either to turn
the screw breech A or to draw it back-but as the screw threads upon the screw
breech piece are interlocking with the screw threads in the gun it cannot be drawn
back and therefore it is turned until the screw segments upon its side are disengaged
from the corresponding screw segments in the gun. The lug A³ then comes to the
end of the slot cut away from the front end of the carrier ring and comes opposite to
the end of the longitudinal slot B³ in the ring. Therefore as the outer ring D
continues to be turned and as the screw breech is now prevented from turning but
free to be drawn back it is drawn back into the carrier ring. When the lug A³ by
the backward movement of the breech piece has passed out from the rear end of the
carrier ring the screw breech piece is still prevented from turning by reason of the
screw segments upon it lying in corresponding grooves formed longitudinally on the
inside of the carrier ring.
When the pin arrives at the end of the helicoidal groove in the screw breech piece
and the screw breech piece consequently cannot be drawn back any further its front
end has been drawn back from the bore of the gun and the extractor which comes
back with it has also been drawn back clear of the gun and as the turning movement
of the handle D is continued the carrier ring being now no longer restrained from
being turned around the pin C is turned around this pin and carries the breech piece
to one side leaving the rear end of the gun open. The arm B then comes against the
fixed stop E which prevents all further movement of the carrier ring.
The extractor on commencing to open the breech is first drawn back slowly a short
distance by the action of the screw thread on the breech piece and consequently has
great power to start back the cartridge case. When the breech piece is drawn back-
wards, the teeth on the extractor being still interlocked with the screw segment on
the breech piece, the extractor is drawn back with it and carried back into a groove
in the carrier ring as shewn at Figure 4. Immediately that it has been drawn back
into this position and the carrier ring is turned to one side the stop plate B* fixed on
the boss comes in front of the flange of the extracted cartridge case.
The cartridge
case is then removed by hand and a fresh one inserted in its place, the stop plate B³
preventing this cartridge from being inserted too far and arresting it in proper
position for the front end of the breech piece to come into position in rear of it and
the hook of the extractor to come in front of the rim on its base when the breech is
being again closed.
The edge of the carrier ring which first comes against the rear end of the cartridge
case at the time when the breech is being closed may be somewhat bevilled off so that
should the cartridge have rebounded somewhat from the stop plate B* or not have

page_text: been pushed home to it this bevilled edge may push the cartridge forward up to the
stop plate and allow the breech screw to be brought into position behind it.
The closing of the breech is effected by turning the handle D' in the opposite
direction to that required for opening it.
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. Breech mechanism consisting of divided segments of screw threads in the gun
within its breech end; a breech piece having corresponding segments to lock into
them and also having an inclined groove passing partly around it; a carrier ring into
which the rear end of the breech piece extends; a short arm extending from the ring
and capable of being turned around a pin projecting rearwards from the breech end
of the gun; a ring with lever handle extending from it capable of being turned
around the carrier ring and a pin projecting inwards from this ring-and entering the
inclined groove in the breech piece; the whole so disposed that on the ring being
turned in one direction the breech piece has first a partial turn given to it is then
drawn back and then by the continued movement of its lever handle carried to one
side of the gun.
2. In breech mechanism having divided screw segments in the breech end of the
gun and in the breech piece; the breech piece A with the inclined groove A² and
the pin D entering the said groove and by a continuous rotary movement around
the axis of the gun first rotating the breech block until it is unlocked and then
withdrawing it.
3. Breech loading mechanism substantially as described and represented in the
annexed drawings.
Datal this 15th due of November 1888