Year: 1887

page_text: Date of Application, 20th Aug., 1887
Complete Left, 18th May, 1888
Complete Accepted, 22nd June, 1888
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:-
This invention has for its object improvements in machine guns.
In my improved machine guns there is fixed at the rear end of the barrel a frame
trough like in form but with an opening at the bottom extending nearly from end to
end and occupying the greater part of its width. There is a breech block which is
slidden to and fro in the frame to close the breech end of the barrel. The breech
block drops into the trough like frame from the top and is secured therein by a cover.
The cover carries the cartridge hopper or magazine from which cartridges are supplied
to the gun. There is besides a locking block which is also able to slide to and fro in
the trough like frame. The locking block is supported by trunnions on either side of
it and these rest upon guide ledges on the sides of the frame. The locking block can
turn about these trunnions through an angle of 40 degrees or thereabout. The locking
block is provided with a handle projecting downwards from it through the opening in
the bottom of the trough like frame. At the rear end of the frame the guide ledges
are cut away to allow the trunnions of the locking block to pass. In this way the
locking block is put up into its place and the breech block is then dropped down over
it. The breech block being suitably recessed or cut away to admit of this and the
cover then being closed down retains the parts in their proper working positions;
they engage the one with the other so that when the locking block is drawn rear-
wards or thrust. forwards it carries the breech block with it along the trough like
frame. The locking block has two arms and these have at their ends enlargements
concentric with the trunnions; they serve as locking bolts. When the breech is

page_text: closed these locking bolts occupy grooves in the sides of the trough like frame and
they project out of these grooves into corresponding grooves in the sides of the breech
block. So the breech block is securely held and it cannot slide longitudinally in the
frame until the bolting parts have been withdrawn by the movement of the locking
block around its trunnions. To open the breech this movement is given to the breech
block by drawing its handle rearwards; the bolting parts then pass out of the grooves
and as soon as they are free, the handle being still drawn rearwards, both the locking
block and the breech block slide along the trough like frame and the face of the breech
block is drawn back from the barrel, leaving the barrel open at its rear end. An
extractor is fixed upon the breech-block and this withdraws the cartridge case from
the barrel, and when free the case falls out through an opening in the bottom of the
trough-like frame. The withdrawal of the cartridge case from the barrel is facilitated
by projections upon the locking block near to the trunnions, which immediately the
bolting parts are free come against shoulders provided for the purpose upon the trough
like frame; these act as fulcra and enable the lever to operate with great power to
initiate the rearward movement of the breech block. The breech block has a striker
or firing pin within it which is pressed forward by a coiled spring-this spring acts
directly upon a piston or disc which serves as a carrier for the firing pin and the
firing pin can slide through the piston or dise for a short distance. There is another
coiled spring operating between the disc and the firing pin and which tends to hold
the latter back.
When the firing pin is released as hereinafter described the principal spring
projects it rapidly forward but the piston or disc is stopped by reaching the end of
the cavity in which it works before the point of the firing pin has struck the priming
of the cartridge; the momentum of the firing pin however carries it further forward
and the cartridge is fired. Immediately afterwards the secondary spring draws the
firing pin back a short distance.
Wings project from the firing pin on either side, they protrude into the grooves or
recesses of the breech-block which receive the locking bolts.
On the locking bolts there are inclines which operate against these wings.
In opening the breech after firing a pair of inclines press the firing pin forward to
get it out of the way to allow other inclines on the locking block which are then above
the wings of the firing pin to retire downwards past them.
This forward movement of the firing pin however is not sufficient to bring its nose
again into contact with the priming of the cartridge, as otherwise there might be risk
of now firing a cartridge which had previously missed fire.
Immediately the inclines have passed down, the firing pin returns. The breech-
block is now drawn back, the cartridge case is got rid of, and another cartridge
descends out of the magazine into a position to be thrust into the barrel. To close the
breech behind the cartridge and to fire the parts are thrust forward again, and as
the locking block turns upwards locking the breech-block, as already explained the
inclines, which it carries, encounter the wings on the firing pin and they drive it rear-
wards, thereby compressing the main spring behind the firing pin. The firing pin is
kept back by the inclines until the breech is securely closed and at this time they
allow the wings to escape beneath their lower ends. The firing pin is then thrown
forward and the cartridge in the barrel is exploded.
The cartridges in the magazine are arranged one over the other, their base flanges
are retained in grooves and the projectiles inclining upwards rest against the front of
the hopper. The head of the undermost cartridge is received into a shoe or holder
which is able to slide to and fro for a short distance. This shoe has a projection on
its underside, and as the breech is closed, it is pressed forward by a corresponding
projection upon the breech-block. The cartridge which is next to enter the gun now
rests with the point of its projectile on an incline and its rim on flanges in the hopper.
The shoe prevents the cartridges going far enough back to fall through. The cartridge
now occupies approximately a horizontal position. When the breech block is drawn
back another projection upon it comes against the projection on the shoe and moves it
a short distance to the rear this allows the rim of the cartridge to go back to the

page_text: part of the hopper which is sufficiently open to allow the rim to pass through
and at the same time the projectile escapes from the supporting incline at the front of
the hopper.
The cartridge now falls into place to enter the barrel; its projectile rests upon a
shelf provided for it immediately in rear of the barrel and its base flange rests upon
the bottom of the trough-like frame which, although open sufficiently for the escape
of the case after firing will not allow the base flange to pass, for the cartridge is now
somewhat in advance of the position to which the cartridge case is withdrawn, after
firing, before it becomes free to fall away.

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 :—
This invention has for its object improvements in machine guns.
In my improved machine guns there is fixed at the rear end of the barrel a frame
trough like in form but with an opening at the bottom extending nearly from end to
end and occupying the greater part of its width. There is a breech block which is
slidden to and fro in the frame to close the breech end of the barrel. The breech
block drops into the trough like frame from the top and is secured therein by a cover.
The cover carries the cartridge hopper or magazine from which cartridges are
supplied to the gun. There is besides a locking block which is also able to slide to
and fro in the trough like frame. The locking block is supported by trunnions on
either side of it and these rest upon guide ledges on the sides of the frame. The
locking block can turn about these trunnions through an angle of 40 degrees or there-
about. The locking block is provided with a handle projecting downwards from it
through the opening in the bottom of the trough like frame. At the rear end of the
frame the guide ledges are cut away to allow the trunnions of the locking block to
pass. In this way the locking block is put up into its place and the breech block is then
dropped down over it. The breech block being suitably recessed or cut away to admit
of this and the cover then being closed down retains the parts in their proper working
positions; they engage the one with the other so that when the locking block is
drawn rearwards or thrust forwards it carries the breech block with it along the
trough like frame. The locking block has two arms and these have at their ends
enlargements concentric with the trunnions; they serve as locking bolts. When the
breech is closed these locking bolts occupy grooves in the sides of the trough like
frame and they project out of these grooves into corresponding grooves in the sides
of the breech block. So the breech block is securely held and it cannot slide longi-
tudinally in the frame until the bolting parts have been withdrawn by the movement
of the locking block around its trunnions. To open the breech this movement is
given to the locking block by drawing its handle rearwards; the bolting parts then
pass out of the grooves and as soon as they are free, the handle being still drawn
rearwards, both the locking block and the breech block slide along the trough like
frame and the face of the breech block is drawn back from the barrel, leaving the
barrel open at its rear end. An extractor is fixed upon the breech block and this
withdraws the cartridge case from the barrel, and when free the case falls out through
an opening in the bottom of the trough like frame. The withdrawal of the cartridge
case from the barrel is facilitated by projections upon the locking block near to the
trunnions, which immediately the bolting parts are free come against shoulders
provided for the purpose upon the trough like frame, these act as fulcra and enable
the lever to operate with great power to initiate the rearward movement of the breech
block. The breech block has a striker or firing pin within it which is pressed forward

page_text: by a coiled spring this spring acts directly upon a piston or disc which serves as a
carrier for the firing pin and the firing pin can slide through the piston or disc for a
short distance. There is another coiled spring operating between the disc and the
firing pin and which tends to hold the latter back.
When the firing pin is released as herein after described the principal spring
projects it rapidly forward but the piston or disc is stopped by reaching the end of
the cavity in which it works before the point of the firing pin has struck the priming
of the cartridge the momentum of the firing pin however carries it further forward
and the cartridge is fired. Immediately afterwards the secondary spring draws the
firing pin back a short distance.
Wings project from the firing pin on either side, they protrude into the grooves or
recesses of the breech block which receive the locking bolts.
On the locking bolts there are inclines which operate against these wings.
In opening the breech after firing a pair of inclines press the firing pin forward to
get it out of the way to allow other inclines on the locking block which are then
above the wings of the firing pin to retire downwards past them.
This forward movement of the firing pin however is not sufficient to bring its
nose again into contact with the priming of the cartridge, as otherwise there might
be risk of now firing a cartridge which had previously missed fire.
Immediately the inclines have passed down, the firing pin returns. The breech
block is now drawn back, the cartridge case is got rid of, and another cartridge
descends out of the magazine into a position to be thrust into the barrel. To close
the breech behind the cartridge and to fire the parts are thrust forward again, and as
the locking block turns upwards locking the breech-block, as already explained the
inclines, which it carries, encounter the wings on the firing pin and they drive it rear-
wards, thereby compressing the main spring behind the firing pin. The firing pin is
kept back by the inclines until the breech is securely closed and at this time they
allow the wings to escape beneath their lower ends. The firing pin is then thrown
forward and the cartridge in the barrel is exploded.
The cartridges in the magazine are arranged one over the other, their base flanges
are retained in grooves and the projectiles inclining upwards rest against the front of
the hopper. The head of the undermost cartridge is received into a shoe or holder,
which is able to slide to and fro for a short distance. This shoe has a projection on
its underside, and as the breech is closed it is pressed forward by a corresponding
projection upon the breech block. The cartridge which is next to enter the gun now
rests with the point of its projectile on an incline in the hopper. The shoe prevents
the cartridges going far enough back to fall through. The cartridge now occupies
approximately a horizontal position. When the breech block is drawn back another
projection upon it comes against the projection on the shoe and moves it a short
distance to the rear, this allows the rim of the cartridge to go back to the part of the
hopper which is sufficiently open to allow the rim to pass through and at the same
time the projectile escapes from the supporting incline at the front of the hopper.
The cartridge now falls into place to enter the barrel its projectile rests upon a
shelf provided for it immediately in the rear of the barrel and its base flange rests
upon the bottom of the trough like frame which, although open sufficiently for the
escape of the case after firing will not allow the base flange to pass, for the
cartridge is now somewhat in advance of the position to which the cartridge case
is withdrawn, after firing, before it becomes free to fall away.
.
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

page_text: Figure 4 is a transverse section on the line 4-4 in Figure 3 and shows the parts in
front of the section line.
Figure 5 is a transverse section on the line 5-5 in Figure 3 and shows the parts
in rear of the section line.
Figure 6 is a side elevation.
Figure 7 is a plan and
Figure 8 is a rear elevation of the breech block.
Figure 9 is a side elevation and
Figure 10 is a plan of the locking block.
Figure 11 is a section on the line 11-11 in Figure 9 and shows the parts in front
of the section line.
Figures 12 show the handle of the locking block.
Figures 13 show the firing pin and in one of these figures the springs in connection
with the firing pin and the piston or disc by which the firing pin is carried are also
shown.
Figures 14 show the extractor.
Figures 15 show the spring bolt which serves to retain the cover in position.
Figures 16 show the shelf or support which receives the nose of the cartridge when
it descends from the cartridge hopper; it is carried by a spring which allows it to
descend out of the way when the breech block advances.
Figure 17 is a longitudinal section of the cover together with the cartridge
hopper upon it.
Figure 18 is a plan of the cover, one half in section on the line 18-18 in
Figure 17.
Figure 19 is a rear elevation of the cover and hopper.
Figure 20 is a section on the line 20-20 in Figure 17.
Figure 21 is a side elevation of the shoe working in the hopper, Figure 21" is a
plan and Figure 21 is a front elevation of the same.
Figures 22 show a slide which closes an opening in the hopper in rear of the shoe.
Figure 23 shows to a smaller scale a side elevation of an entire gun.
Referring to Figures 2, 3, 4 and 5, a a¹ are the trunnions by which the gun
is carried upon a suitable carriage or support, a² a² are lugs by which the cover is
connected with the frame, a³ is a hole for the locking bolt shown by Figures 15; this
bolt is connected with the frame by a screw as indicated.
aa are surfaces upon the top of the frame which support and guide the breech
block as it is moved to and fro.
a a are guide ledges on the sides of the frame which support and guide the
trunnions of the locking block. * are surfaces at the fore ends of the ledges a with
which lugs on the locking block come in contact towards the end of its forward
movement.
a is the opening between the ledges as to allow the trunnions of the locking block
to enter when putting the parts of the mechanism together.
a is the face at the rear end of the frame with which the breech block comes into
contact when it is drawn back and which thus limits its motion.
a are curved grooves in the frame to receive the bolts of the locking block.
aa are surfaces against which the bolts of the locking block bear when the block
is drawn rearwards.
a10 a10 are the bottom projections on the frame which prevent the cartridge falling
through and which support and guide the base flange.
a is the opening to receive the part shown by the Figures 16.
In Figures 6, 7 and 8 are flanges on the top of the breech block which rest on
the surfaces a. is a plate at the back of the breech block which can be removed to
admit the firing pin and parts shown by the Figures 13 to the cavity formed within
the breech block to receive them; this cavity is indicated by dotted lines. 6363 are
grooves to receive the curved bolts of the locking bolt. is a recess to receive the
cross bar or axis of the locking block. 65 65 are slots through which the wings
of the firing pin project into the grooves b³. 666 are recesses to receive the extractor.

page_text: are projections for operating the shoe in the cartridge hopper; the front
projection stands between the claws of the extractor.
In Figures 9, 10 and 11 c c are the trunnions of the locking block which rest on
the surfaces a. is the stem which receives the handle. 3 is the cross bar or axis
which is received into the recess and which so serves to connect the breech block
with the locking block. etc are the arms of the locking block. c c are the curved
bolts which these arms carry. c c are the surfaces on the bolts c which bear on the
guide surfaces a a³ as the locking block travels to and fro. c c are the inclines
which operate upon the wings of the firing pin. ex are notches in these inclines
which retain the wings of the firing pin until a final forward movement is given to the
handle of the locking block, so that the gun is not necessarily fired immediately after
loading. is the part of the incline which moves the firing pin forward immediately
before opening the breech.
In Figures 13 d is the main spring which thrusts the piston or disc e forward when
the firing pin is released. fi are the wings of the firing pin, they are acted upon
by the inclines c in the manner already described. The stem of the firing pin passes
through the piston or disc e and the spring g surrounds it. This stem allows the
firing pin to move forward a short distance after the piston lias come to rest; the
springy afterwards retracts the firing pin.
Figures 14 and 15 do not need further description.
In Figures 16 ¹ is the surface on to which the nose of the cartridge falls when it
descends from the magazine and 2 is an incline against which the breech block comes
when it advances and so the support when it has served its purpose is thrust down out
of the way.
In respect to Figures 17 to 22 is the joint of the cover and is the whole to
receive the bolt which locks the cover in place where it aids in guiding the breech
block. are the inclined grooves in the cartridge hopper which retain and guide the
base flanges of the cartridges. is the surface against which the fore end of the
cartridge rests so long as the cartridge inclines upwards.
is an incline which supports the nose of the cartridge when it has assumed
a nearly horizontal position preparatory to falling into position in rear of the
barrel.
are grooves or recesses in which the shoe Figure 21 works.
and
are recesses in the arms 22 of shoc which when the shoe is in its forward
position form continuations of the inclined grooves the base flange of the cartridge
when the recesses are presented to it drops down until it rests upon the
surfaces.
When on the breech block being drawn back the shoe also is moved rearwards
it draws back the cartridge which has descended into the shoe until it escapes from
the supporting surfaces at and 8. The next cartridge then descends in the hopper
until its base flange rests on the arms 2 and its nose on the incline .
3 is the part of the shoe with which the projections on the breech block come
in contact in order to impart to the shoe the requisite movements. When the
cartridge is liberated in the manner described it falls in front of the breech block and
remains with the nose of the projectile supported by the instrument shown by
Figure 13 and its base flange rests on the surfaces a. When the breech block
advances the cartridge is thrust into the barrel and it is then fired as already explained.
When the breech block next retires it withdraws the cartridge case from the barrel and
draws it back until the base flange passes back beyond the surfaces a⁰ and the case
then falls away and the new cartridge immediately afterwards drops down from the
hopper.
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 1
claim is
1. In a machine gun the combination substantially as described of the frame in rear
of the barral, the breech black liding in the from the leaking Wook inintel L

page_text: engaging with the breech block; and the bolts on the locking block entering grooves
in the sides of the frame and other grooves in the sides of the breech block and so
securing the breech block to the frame in position to close the barrel behind the
cartridge.
2. In a machine gun, the combination substantially as described of the frame in
rear of the barrel; the breech block sliding in the frame and controlled by guide
surfaces on the top of the frame and in a cover closing over it; the locking block
jointed to or engaging with the breech block; and the bolts on the locking block
entering grooves in the sides of the frame and other grooves in the sides of the breech
block.
3. In a machine gun, the combination substantially as described of the frame in
rear of the barrel; the breech block sliding in the frame; the locking block supported
by its trunnion on guide ledges in the frame and further controlled by guide surfaces
beneath the frame; such locking block also engaging with or being jointed to the
breech block and having bolts entering grooves in the sides of the frame and other
grooves in the sides of the breech block.
4. In a machine gun, the combination substantially as described of the frame in rear
of the barrels; the breech block sliding in the frame; the locking block jointed to or
engaging with the breech block; the bolts on the locking block; and the inclines on
the bolts operating the firing mechanism as the bolts are inserted to secure the breech
block.
5. In a machine gun, the combination substantially as described of the frame in
rear of the barrel; the breech block sliding in the frame; the cover; the cartridge
hopper upon the cover; the shoe in the cartridge hopper and projections on the
breech block operating the shoe.
6. A machine gun substantially as described and represented by the annexed
drawings.
Dated this 19th dose of Mo.. 1000