IMPROVEMENTS IN BATTERY OR MACHINE GUNS
Year: 1880

page_text: LETTERS PATENT to Thorsten Nordenfelt, of No. 1, St. Swithin's Lane, in
the City of London, Civil Engineer, for an Invention of "IMPROVEMENTS IN
BATTERY OR MACHINE GUNS."
PROVISIONAL SPECIFICATION left by the said Thorsten Nordenfelt at the
Office of the Commissioners of Patents on the 30th November 1880.
THORSTEN NORDENFELT, of No. 1, St. Swithin's Lane, in the City of London,
Civil Engineer. "IMPROVEMENTS IN BATTERY OR MACHINE GUNS."
The object of this Invention is to render machine guns, especially those of large
calibres, more safe and more perfect in mechanism as well as more perfect for
taking up the recoil, and for facilitating the quick change of aim with the gun.
The gun consists of two or more barrels lying in a horizontal plane or in an arc;
their breech ends are screwed into a centre cross piece, whilst the muzzle ends
pass through and slide in the front cross piece which is keyed to the trunnion
frame.
The plan of trunnion frame forms three sides of an oblong, the front cross piece
when keyed on completing the quadrilateral.
The centre cross piece is bolted to the inner or sliding frame, the plan of which
forms three sides of a quadrilateral, leaving the centre cross piece to form the
fourth.
The sliding frame fits into the outer or trunnion frame to the rear of the
trunnions; flanges formed along the top edges of sliding frame rest upon top edges
of trunnion frame, thus supporting the centre cross piece in such a position that
when the barrels are screwed in and passed through the front cross piece, their
axes will be parallel to top and bottom edges of outer frame behind the trunnions,
thus leaving the inner frame carrying the centre cross piece and breech ends of
barrels free to slide upon and in the outer frame, whilst the muzzle ends are
supported and free to slide in front cross piece.
When in firing position, the rear end of inner frame stands a little in advance
of rear end of outer frame; a strong flat spring is placed between the two ends;
when the gun is fired this spring is compressed and so assists in taking up the
recoil; in addition to this two strong spiral springs, which lie parallel with the
Din 1

page_text: axes of barrels and in front of the centre cross piece, are at the same time com-
pressed; each spring is carried on a spindle screwed into the fore end of inner
frame; this spindle passes through a stiff bracket inside the frame opposite the
trunnions; the spring is put on and fastened with nuts by which the amount of
compression can be regulated. The feeding is effected by the cartridges being fed
through the cover (in which are openings similar in shape to the cartridges) on to
the cartridge plate; this plate being moved at the rear end of stroke of lever allows
one layer of cartridges to fall into recesses provided for them in the breech block,
these recesses at this time being opposite the open ends of barrels, the forward
motion of the lever causes plungers to push the cartridges into the chambers and
continuing carries the breech block to the right, and so close the breeches and at
the same time firing the cartridges.
The mechanism for loading, closing the breech, and extracting is set in motion
by a lever pivoted to the inner frame at one end, and furnished with a handle
at the other; this handle is grasped by the gunner and moved through an arc in
a plane parallel to the plane in which the barrels lie. In this lever is a cam
shaped groove in which works a friction roller attached to a plate carrying the
plungers.
The plungers run in semi-circular recesses cut in upper surface of breech block,
and serve to push the cartridges into the chambers; they also carry the extractors
for clearing the chambers of the empty cases after firing.
The mechanism for firing the cartridges is carried in the breech block between
the aforesaid semicircular recesses; it is therefore necessary when the cartridges
have been pushed home into the chambers to carry the breech block across (or in
a line parallel with axis of trunnions) to bring the firing pins opposite the cap,
when the hammers are released either simultaneously or in succession as considered
necessary.
The firing is effected by a spiral spring driving a hammer (or pin carrier)
carrying the firing pin; the blow is not struck directly from the hammer through
the firing pin on to the cap but by the momentum (or inertia) of the firing pin;
by these means the firing pin has no pressure upon it when the point is beyond
the face of breech block. The hammer may be described as a hollow cylinder with
a nose or projection on the top of rear end, and a tail or lengthened projection from
its lower rear surface.
The firing pin tits loosely into the hammer in which it is retained by a cotter;
the cotter slot in firing pin is about 1/4" longer than width of cotter, by which a
certain amount of lateral freedom independent of the hammer is obtained.
During the back stroke of hand lever the tail of hammer is caught by a stud
upon the friction roller plate and carried backward, compressing the spiral spring
and taking with it the firing pin; when nearly home on its backward journey the
nose, one end of which is inclined and comes in contact with a similarly inclined
surface on hammer catch which it raises, passes under, and is retained by when
the lever commences its forward movement.
At the end of forward stroke the hammer catch is raised and the hammer
actuated by the spiral spring flies forward until stopped by a shoulder; the firing
pin however having received no check continues its journey and fires cartridge.
The hammer catch is pivoted into the breech block; one end is furnished with a
hook to retain hammer, the other end which stands above top surface of breech
block is inclined at an angle of 45°; in firing this top end is forced down either
by the motion of trigger comb whilst the breech block remains stationary, or by
the motion of breech block whilst the trigger comb remains stationary.
The trigger comb is simply a flat plate with openings in its front edge to suit
hammer catches; it is attached to top of breech block by thumb screws which allow
it a slight transverse motion; when the screws are turned 1/, revolution the trigger
comb may be taken out of gun.
The spring bar is attached to rear end of breech block and serves to retain the
spiral springs in position.

page_text: The breech block with spring bar attached is of such size as to fill the space
between centre cross piece and rear end of inner frame in a longitudinal direction,
whilst in the transverse direction it is about the diameter of the cartridge head,
narrower than the width across inside of frame; it will thus be seen that the only
motion the breech block can have will be a transverse motion corresponding to
diameter of cartridge head.
The breech block is supported by and slides upon the runners attached to rear
end of inner frame and centre cross-piece.
The cartridge plate which lies upon the top surface of breech block has openings
similar to those in the cover, which it is immediately under, it has a transverse
motion independently of the breech block, communicated to it by a cam shaped slot
cut in the top surface of one or more of the plungers; a friction roller attached to
the plate works in this slot; its motion commences when the head of the cartridge
case being extracted is to the rear of the cartridge lying in the cover and on the plate,
and having allowed this cartridge to fall into semi-circular recess in breech block,
it returns to its position before the plunger commences to push the lower cartridge
forward, thus ensuring that the head of the upper cartridge does not lie on and in
front of the head of lower. When the breech block commences its transverse
motion the plate is carried with it, being held by' a catch which is only released
whilst the roller is in slot of plunger.
The cover pivots upon centre cross piece, and when closed shuts in the
mechanism, the only communication being through the cartridge openings.
Friction roller plate is a plate the width of breech block which is immediately
under; on its under side is the friction roller, to work in hand lever, and also a
stud to work in guide plate attached to centre cross piece; on its upper surface are
projections to which the plungers are attached by screwed cross pins, which serve
to hold the plate up; there are also studs which project upwards into the hammer
head grooves and serve to cock the hammers as before explained its motion
is partly in the direction of axes of barrels, when it works independently of
the breech block and partly at right angles to it, when it carries the breech block
with it.
Whilst the friction roller plate is making its forward movement the right hand
slides against the guide until its front edge comes in contact with the centre cross
piece, this prevents any further forward movement, and the guide, which has
terminated, offering no resistance to right hand side of plate, its direction is
changed.
The centre cross piece has slots cut in it for the passage of the extractors, which
move to the right clear of the cartridges during firing.
The guides for friction roller plate are attached to side of frame and centre cross
piece.
To sum up, the action is as follows:-The backward stroke of the hand lever
first carries breech block to the left, and so brings plungers in line with the barrels
and extractor hooks over cartridge heads; secondly, withdraws plungers, and so
extracts empty cases from chambers; thirdly, compresses spiral springs and cocks
gun, during which time the empty cases have fallen through openings in breech
block and the cartridge plate has been moved to the left, allowing another supply
of cartridges to fall into the breech block. The motion of hand lever being now
reversed first closes the cartridge plate; secondly, pushes the cartridges into the
chambers; thirdly, moves the breech block to the right to close the breeches and
bring the firing pins opposite the caps; and, fourthly, releases the hammers and fires
if it is considered necessary to fire by action of hand lever.
I have also devised a means of elevating and depressing the guns more quickly
and steadily than before by placing on the gun carriage two or three wedge shaped
blocks with their points in opposite directions, that is, one or two wedges with
their points towards the muzzles of the barrels and one or two wedges with their
points towards the breech ends, on the framework of the gun on both sides of the
trunnions are fixed the same number of brackets, rollers, or other supports, each of

page_text: which rests upon its corresponding wedge. As this system of wedges is drawn
rearwards by a screw or by rack and pinion gear, the forward support will be
raised and the rear support will be correspondingly lowered whereby the gun is
elevated, still being. held absolutely firmly at every position by the supports
pressing the gun up against its trunnion caps, and vice versa if the system of
wedges is pushed forwards.
The slanting surfaces of the wedges can be adjusted so as to approach one
another if desired for counteracting the wear and tear or for cramping the gun in
any fixed position.
I can also vary this mode of holding the gun firmly for elevating purposes and
gain approximately the same wedge or lever motion by having the following
arrangements in lieu of the actual wedge, viz., either a sliding bar on the carriage
moved forward from backwards by means of a screw, such sliding bar to have at
each end or at its centre two rods connecting it with the gun; these connecting
rods to be at an angle, and to have joints at each end. In this way as the sliding
bar moves rearwards the rear connecting rod is raised and the front rod lowered,
and the gun acted upon in the same manner, and when the sliding bar is moved
forward the opposite action takes place.
Or else instead of the sliding bar I can have a wheel placed vertically on an
axis, which wheel can be moved by a conical rack. On this wheel at each side of
the axis I would have the same connecting rods attached, their other ends being
attached to the gun, when it will be seen that as I move the wheel by means of
the rack in one direction the one connecting rod will push the one end of the gun
upwards, while the other connecting rod bears the other end of the gun downwards,
and vice versa.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Thorsten Nordenfelt in the Great Seal Patent Office on the
30th May 1881.
THORSTEN NORDENFELT, of No. 1, St. Swithin's Lane, in the City of London,
Civil Engineer.
"IMPROVEMENTS IN BATTERY OR MACHINE GUNS."
The object of this Invention is to render machine guns, especially those of larger
calibres, more safe and more perfect in mechanism.
The annexed Drawings represent a battery or machine gun constructed in
accordance with my Invention.
Figure 1 is a longitudinal section taken upon the line 1, 1, in Figure 3.
Figure 2 is a longitudinal section taken upon the line 2, 2, in Figure 3.
Figure 3 is a plan.
Figure 4 is a transverse section taken upon the line 3, 3, in Figure 1.
Figure 5 is a transverse section taken upon the line 4, 4, in Figure 1.
The gun consists of two or more barrels (1) lying in a horizontal plane or in
an arc, their breech ends are screwed into a centre cross piece (2) whilst the
muzzle ends pass through and slide in the front crosspiece (3) which is keyed to
the trunnion frame (4).
The plan of trunnion frame forms three sides of an oblong, the front cross-
piece (3) when keyed on completing the quadrilateral.
The centre crosspiece (2) is bolted to the inner or sliding frame (5), the plan of
which forms three sides of a quadrilateral, leaving the centre crosspiece to form the
fourth.
The sliding frame fits into the outer or trunnion frame (4) to the rear of the
trunnions (6). Flanges formed along the top edges of the sliding frame rest upon
top edges of the trunnion frame, thus supporting the centre crosspiece in such a
position that when the barrels are screwed in and passed through the front cross-
piece their axis will be parallel to the top and bottom edges of the outer frame
behind the trunnions, thus leaving the inner frame carrying the centre crosspiece
and breech ends of the barrels free to slide upon and in the outer frame, whilst the
muzzle ends are supported and free to slide in the front crosspiece (3).
When in firing position the rear end of the inner frame stands a little in advance
of rear end of outer frame, and a strong flat spring (7) of steel or india rubber is
placed between the two ends. The spring represented in the Drawing is composed
of alternate plates of steel and of india rubber perforated to render it more
compressible. When the gun is fired this spring is compressed, and so assists in
taking up the recoil. In addition to this, two strong spiral springs (8) which lie
parallel with the axis of barrels and in front of the centre cross piece are at the
same time compressed; each spring is carried on a spindle (9) screwed into the fore
end of inner frame, and this spindle passes through a stiff bracket (10) inside
the frame (4) opposite the trunnions. The spring is put on and fastened with nuts
by which the amount of compression can be regulated. The feeding is effected
through the cover (11) in which are openings and passages (12) similar in shape to
the cartridge. The cartridges descend on to the cartridge plate (13); this plate
being moved as hereinafter described, at the rear end of the stroke of the lever,
allows one layer of cartridges to fall into recesses provided for them in the breech
block (14), these recesses at this time being opposite the open ends of barrels.
The forward motion of the lever (15) causes plungers (16) to push the cartridges
into the chambers, and continuing carries the breech block which is able to slide
transversly in the frame (5) to the right, and so closes the breeches, at the same
time firing the cartridges.

page_text: The mechanism for loading, closing the breech, and extracting it is set in motion
by a lever (15) pivoted to the inner frame (5) at one end, and furnished with a
handle at the other. This handle is grasped by the gunner and moved through an
are in a plane parallel to the plane in which the barrels lie. In Figure 3 the
lever (15) is seen about mid-position. In this lever is a cam shaped groove
in which works a friction roller (17) attached to a plate (18) carrying the
plungers (16).
The plungers fit and run in semi-circular or U form recesses cut in upper surface
of the breech block (14) and serve to push the cartridges into the chambers; they
also carry the extractors for clearing the chambers of the empty cases after firing.
Each plunger has an extracting hook on one side, as is clearly seen in Figure 3.
The mechanism for firing the cartridges is carried in the breech block (14) between
the aforesaid semicircular recesses; it is therefore necessary when the cartridges
have been pushed home into the chambers to carry the breech block across (or in
a line parallel with axis of trunnions) to bring the firing pins (19) opposite the
caps of the central fire cartridges, and then the hammers are released either
simultaneously or in succession, as considered necessary.
The firing is effected by a spiral spring (21) driving a hammer (or pin carrier) (20)
carrying the firing pin (19). The blow is not struck directly from the hammer
through the firing pin on to the cap, but by the momentum of the firing pin. By
these means the firing pin has no pressure upon it when the point is beyond the
face of breech block.
The hammer (20) may be described as a hollow cylinder with a nose (22) or
projection on the top at the rear end, and a tail (23) or lengthened projection from
its lower rear surface; it fits a recess prepared for it in the breech block, and slides
longitudinally therein.
The firing pin (19) fits loosely into the hammer, in which it is retained by a
cotter. The cotter slot in the firing pin is about 1/4" longer than the width of
the cotter, as seen in Figure 2, by which a certain amount of lateral freedom
independent of the hammer is obtained.
During the back stroke of hand lever (15) it operates against a friction
roller (17) and causes a rearward motion of the plate (18). The tail (23) of
the hammer is caught by a stud (24) upon the friction roller plate (18), and
carried backward, compressing the spiral spring (21) and taking with it the
firing pin. When nearly home ou its backward journey the nose (22), one end
of which is inclined and comes in contact with a similarly inclined surface on the
hammer catch (25), which it raises and passes under, and the spring of the hammer
catch causing it to engage with the nose the hammer is retained when the lever
cominences its forward movement. At the end of forward stroke the hammer
catch is raised by means herein after described, and the hammer actuated by the
spiral spring flies forward until stopped by a shoulder; the firing pin however
having received no check continues its journey, and striking the cap fires the
cartridge.
The hammer catch (25) is pivoted into the breech block (14); one end is
furnished with a hook to retain the hammer, and the other end which stands above
the top surface of the breech block is inclined at an angle of 45°, as is seen in Figure 5.
In firing, this top end is forced down either by the motion of trigger comb (26)
whilst the breech block remains stationary, or by the motion of the breech block
whilst the trigger comb remains stationary.
The trigger comb is simply a flat plate with openings in its front edge to suit
the hammer catches; it is attached to top of breech block by thumb screws, which
passing through slotted holes allow it a slight transverse motion. When the screws
are turned / revolution the trigger comb may be taken out of gun.
The spring bar (27) is attached to rear end of breech block, and serves to retain
the spiral springs in position; it in effect forms part of the block when in
operation.
The breech block (14) with spring bar (27) attached is of such size as to fill the

page_text: space between the centre crosspiece (2) and the rear end of the inner frame (5) in
a longitudinal direction, whilst in the transverse direction it is about the diameter
of the cartridge head, narrower than the width across the inside of frame. It will
thus be seen that the only motion the breech block can have will be a transverse
motion corresponding to diameter of cartridge head.
The breech block is supported by and slides upon the runners (28) attached to
rear end of inner frame (5) and centre crosspiece (2); the way in which it obtains
its transverse motion will be presently described.
The cartridge plate (13) which lies upon the top surface of breech block (14) has
openings similar to those in the cover, which it is immediately under. It has a
transverse motion, independent of the breech błock, communicated to it by a cam
shaped slot (29) cut in the flat top surface of one (or more) of the plungers (16).
When the plunger comes back a friction roller (30) attached to the plate (13)
enters and works in this slot. Its motion commences at the time for supplying
fresh cartridges, and when the head of the cartridge case being extracted is to the
rear of the cartridge lying in the cover and on the plate (13). When the apertures
in the plate (13) correspond with the passages (12) in the cover (11) the cartridges
fall through, and having allowed this cartridge to fall into semi-circular recess in
breech block the plate (13) returns to its position before the plunger commences to
push the lower cartridge forward, thus passing beneath the lower ends of the
passages (12), and ensuring that the head of the upper cartridge in this passage
does not lie on and in front of the head of lower. When the breech block (14)
commences its transverse motion after the cartridges have been pushed home into
the barrels the plate (13) is carried with it, being held by a catch (31) which is
only released whilst the roller is in the slot (29) of plunger. The plunger itself
displaces the catch (31) when it comes back, and keeps it out so long as the
roller (30) is in the oblique part of the groove (29).
The cover (11) pivots upon the centre crosspiece, and when closed shuts in the
mechanism, the only communication being through the cartridge openings.
The friction roller plate (18) is a plate the width of the breech block which it is
immediately under On its under side is the friction roller (17) to work in the hand
lever (15), and also on the right to work against a guide plate (33) attached to
centre crosspiece (2) and inner frame (5). On its upper surface are projections (32)
entering holes in the under sides of the plungers, and to which the plungers are
attached by screwed crosspins which serve to hold the plate up. There are also
studs (24) which project upwards into the hammer head grooves and serve to cock
the hammers, as before explained. The motion of the plate (18) is partly in the
direction of axis of barrels when it works independently of the breech block, and
partly at right angles to it when it carries the breech block with it.
Whilst the friction roller plate (18) is making its forward movement the right
side of it slides against the guide (33) until its front edge comes in contact with
the centre crosspiece (2); this prevents any further forward movements of the
plate (18) and the guide (33), which has terminated behind the position now
occupied by the plate, offering no resistance to right hand side of the plate, its
direction is changed, the slot in the lever (15) being so curved as to cause the
roller (17) to recede from the fulcrum of the lever until the end of the forward
movement.
The centre crosspiece (2) has slots (34) cut in it for the passage of the extractors
during the transverse movement of the block (14). The extractors move to the
right, clear of the cartridges during firing.
The guide (33) for the friction roller plate is attached to side of frame and centre
crosspiece.
To sum up, the action is as follows:-The backward stroke of the hand lever first
carries the breech block (14) to the left, and so brings the plungers (16) in line with
the barrels and the extractor hooks over the heads of the cartridge cases, which at
this time are in the barrels; secondly, the continued movement of the lever with-
draws the plungers (16) and so extracts the empty cases from the chambers;

page_text: thirdly, it compresses the spiral spring (21) and cocks gun, during which time the
empty cases have been brought back along the breech block (14) until the head of
the cartridge cases reaches the rear and wider end of 'the slot in the bottom of the
block when it is able to fall through. The cases of the used cartridges have thus
fallen through openings in the breech block (14), and the cartridge plate (13) has
been moved to the left, allowing another supply of cartridges to fall into the breech
block, and then the lever (15) reaches its backward position. The motion of hand
lever being now reversed first closes the cartridge plate (13); secondly, pushes the
cartridge into the chambers; thirdly, moves the breech block (14) to the right to
close the breeches and bring the firing pins (19) opposite the caps; and, fourthly,
releases the hammers and fires if it is considered necessary to fire by action of hand
lever.
The firing takes place in this way:-The firing comb (26) which lies on top of
the plate (13) and block (14) is by the lateral movement of the block brought into
collision with the stop (35), and is so shifted upon the block as to depress the tails
of the catches (25), and the firing then takes place. The comb (26) is replaced by
striking the side frame (5) when next the block (14) moves to the left. When it is
not required to fire by the action of the hand lever the stop (35) is allowed to
spring out, and the firing is brought about when required by thrusting it in.
Having now fully described my improvements in battery or machine guns, I will
in conclusion state what I consider novel and to which I make claim,-
First. The combination with such guns of springs (7) (8) between the outer and
inuer frame taking up the recoil, substantially as herein described.
Second. The hand lever (15) provided with a slot giving the working motion to
the mechanism, substantially as herein described.
Third. The combination of the action plate (18) and plungers (16) and studs (24)
cocking the hammers, substantially as herein described.
Fourth. The breech block (14) moving transversely to the axis of the barrels
and containing plungers (16), and also the firing mechanism in the intervals between
the plungers, substantially as herein described.
Fifth. The combination, consisting of the trigger comb (26), catches (25), and
firing stop (35), operating substantially as herein described.
Sixth. The combination, consisting of the block (14), plungers (16), and cartridge
plate (13), the said plate (13) being carried upon the block (14) and receiving
lateral movement when the plungers are in their rearward position, substantially as
herein described.
Seventh. My improved battery or machine gun, substantially as herein
described.
In witness whereof, I, the said Thorsten Nordenfelt, have hereunto set my
hand and seal, this Twenty sixth day of May, in the year of our Lord One
thousand eight hundred and eighty one.
THORSTEN NORDENFELT. (L.S.)