Improvements in Machine Guns.
Year: 1891

page_text: Date of Application, 10th Aug., 1891
Complete Specification Left, 8th June, 1892-Accepted, 9th July, 1892
PROVISIONAL SPECIFICATION.
Improvements in Machine Guns.
I, JOHN EBENEZER BOUSFIELD, of the firm of G. F. Redfern & Co., the
General Patent Office, No. 4, South Street, Finsbury, in the County of Middlesex,
Patent Agents, do hereby declare the nature of this invention (a communication
to me by Oskar William Bergman, of Gothenbourg, Sweden, Lieutenant of the
Royal Swedish Artillery, and Johan Nilsson of Sweden, Civil Engineer) to be
as follows:-
This invention relates to machine guns the barrels of which are placed in a circle
parallel with an axis around which they revolve.
The outer framework of the gun is of barrel shape and is suspended on trunnions
and contains an inner cylinder which does not revolve. This inner cylinder is
provided with cam grooves acted upon by lugs on the barrels, which cause or
assist the revolving motion of the barrels, and, by lugs on the plungers which
withdraw the plungers after firing.
The barrels are allowed to recoil whereby the vibration of the is diminished
gun
and the accuracy of fire is increased. A lug on the breech end of the barrel or on
the breech-piece strikes an inclined plane on the cam surface on the non-revolving
inner cylinder and tends to turn the barrels round, whilst another inclined plane
on the same cam forces the barrel forward again into firing position.
To a central spindle are fixed two dises which support both ends of the barrels
with the breech-pieces and plungers at their breech ends, these parts revolve.
The plungers which carry the extractors can be locked to the breech-pieces in
any convenient way by a radial turning movement of one of them or by stoppers
or pawls, the locking being in any case effected by the revolving motion of the
breech-piece and plunger in relation to the inner cylinder or the outer frame, which
do not revolve. We prefer the use of pivoting pawls or bolts revolving with the
breech-pieces and plungers, and which are made to engage in the breech-pieces or
plungers before firing, and are unlocked after firing, their motion being caused
by cam surfaces on the non-revolving inner cylinder.
The gun can have any desired number of barrels. Each barrel is accompanied
by its plunger containing the firing pin which, on arriving, during the revolving
motion, opposite the firing mechanism which is lodged in the outer framework and
fires all the barrels successively, is struck by a hammer impelled forward by the
firing spring when released from the trigger catch; the hammer is cocked by the
rearward movement of the previous barrel when recoiling.
The cartridges can be fed to the gun from a flexible band of metal or other
material which can be laid outside the revolving breech-pieces which move the
band forwards, so that a cartridge is inserted in front of each plunger when with-
drawn by its cam or the inner cylinder; or the band can be placed around a
separate feeding cylinder placed outside the breech-pieces at that part of the
mechanism where the plungers are in their rearmost position.
The feeding cylinder is rotated by lugs or teeth on the recoiling barrels or on
the rear disc, sufficiently for feeding one cartridge to such breech-piece as it passes,
the cartridges being carried into position in front of the plungers by elastic planes
or spring cams which withdraw the cartridges from the band and cause them to
enter the breech-pieces.
These machine guns can be fired either by hand or automatically as desired. A
firing handle is provided which engages with the central spindle by means of a
ratchet wheel so that the handle can turn the spindle but so that if the handle is
not turned, the spindle can rotate without turning the handle.

page_text: When the gun is worked by hand, the spindle, actuated by the firing handle,
revolves the barrels, breech-pieces and plungers and actuates the feeding, firing
and extracting mechanisms as above described.
When firing automatically the recoiling barrels, when fired, strike one after the
other upon the inclined plane on the cam surface of the non-recoiling inner
cylinder and cause the barrels to revolve and to actuate all the feeding, firing and
extracting movements as described.
The rear sight placed in the framework consists of a threaded bar, the threads
being cut away at one side for the graduation. The sight bar can be raised
and lowered by means of a nut also lodged in the framework.
Dated this 10th day of August 1891.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Machine Guns.
I, JOHN EBENEZER BOUSFIELD, of the firm of G. F. Redfern & Co.,
No. 4, South Street, Finsbury, in the County of London, Patent Agents, do hereby
declare the nature of this invention (a communication to me by Oskar William
Bergman, of Gothenburg, Sweden, Lieutenant of the Royal Swedish Artillery, and
Johan Nilsson, of Sweden, Civil Engineer) and in what manner the same is to
be performed, to be particularly described and ascertained in and by the following
statement.:-
This invention relates to machine-guns of the kind in which a revolving cluster
or series of barrels, placed parallel with the axis upon which they revolve, is
employed.
The chief object of my invention is to render such a gun automatic and at the
same time to provide means whereby in case of any obstruction to the automatic
working the gun can be operated by hand power.
In the accompanying drawings,
Figure 1 is a plan of the breech end of a machine gun constructed according
to this invention; and,
Figure 2 is a rear elevation of the same.
Figure 3 is a longitudinal section of the breech end of the gun; and,
Figure 3 is a continuation of the section shewn in Figure 3.
Figure 4 represents three sections, that is to say, the half A on the left of the
line is a section on the line A A, Figures 1 and 3, the quarter B to the right
of the line and above the line yy is a section on the line B B, Figure 1,
and the quarter C on the right of the line and below the line is a section on
the line CC, Figure 1.
3 y
Figures 5 to 34 illustrate details in the construction of the gun and are
hereinafter described.
Similar letters of reference indicate corresponding parts in the several figures.
a indicates the outer framework of the gun which is of barrel-shape and formed
in two parts hinged at a and designed to be fastened at a² and which is supported
upon trunnions a³, a³, Figure 34; is a cylinder fixed within the outer casing, and
having formed in it the cam-groove and on it the cam-surfaces b², 63, 64, 65, 6, all
as shewn in Figure 5 which represents a development of the said cylinder b.
c, c are the gun barrels which are arranged around the central shaft or spindle d
supported in suitable bearings in the casing, the said barrels being carried upon
the said shaft at their rear end by the disc d' shewn detached in elevation and in
vertical section in Figures 6 and 7 respectively, and by a.somewhat similar disc at
their front ends, the said barrels c, e sliding through the said discs in the manner.
hereinafter described.

page_text: e, e are the breech-bolts or plungers arranged in conjunction with the barrels
one of which plungers is represented in longitudinal section, plan, rear elevation
and front elevation in Figures 8, 9, 10 and 11 respectively. Each plunger is
carried in a separate breech-piece, one of which is shewn in longitudinal section,
in plan and in rear elevation in Figures 12, 13 and 14 respectively, and in Figures 15
and 16 which respectively represent sections on the lines of Figure 13.
The breech-pieces f, fare secured to the barrels c, by screw-threads and
are made of segmental shape in cross section, as shewn in Figures 14, 15 and 16,
in order that a series of them may occupy a circular space around the spindle d, as
indicated in Figure 4. Each plunger e is provided with a firing-pin e adapted,
when it reaches the required position, to be struck by a hammer g hereinafter
described, and, in conjunction with each plunger, is also arranged an extractor e, as
shewn in Figure 17, which is a longitudinal section through one of the plungers
and breech-pieces and a portion of the connected barrel. This extractor is
arranged independently of the plunger e, that is to say, it is not pivotted or
otherwise fastened to the said plunger but is operated by a lug es, with which it is
provided, entering a recess et in the plunger, the said extractor being adapted to
slide in a groove in the breech-piece. It will be noticed that the recess e is
of a varying depth as also is the groove. This arrangement allows the plunger
to acquire a certain amount of momentum before it commences to extract the
cartridge in a well known manner.
Figure 18 is a view similar to Figure 17 but representing the position of the
parts when the empty cartridge case is withdrawn.
The plungers are reciprocated to open the breeches of their barrels and extract
the empty cases and to again close and force new cartridges into position by lugs/3
thereon engaging in the cam-groove of the fixed cylinder 6; the said groove
being so shaped that each plunger will be moved to open the breech of its barrel
and close it' again during one complete revolution of the barrels.
In order to provide for locking the breech-bolts or plungers e, e against rearward
movement during the discharge of the cartridges, each of the breech-pieces fis
provided with a pivotted pawl of the form shewn in Figures 19, 20 and 21 which
are respectively a side elevation, an end elevation and a plan of one of the said
pawls. Each pawl, as shewn, is formed with two trunnions, adapted to be
carried in bearings upon the breech-piece and is designed at one end to engage
with a notch e in the adjacent plunger or breech-block and at the other end to bear
against the cam or inclined surface of the cylinder b. These pawls are
operated by the cam-surfaces 2, 3, of the cylinder, that is to say, the
surface serves during the recoil of the barrel to move the pawls out of engage-
ment with the plungers, the surface serves to hold the pawls out of engagement
and the surface serves to again place the pawls in engagement with the plungers
at the required time.
The rotation of the cluster of barrels is effected by the following means:-Each
of the breech-pieces is provided with a lug sliding in recesses 2 in the disc d'
so as to prevent the barrel from rotating upon its axis. The rear end of this lug
is formed with inclined surfaces, designed to act upon and be acted upon by
the cam-surfaces 65, 66 of the cylinder b. When, after the firing of a cartridge,
the barrel recoils, the surface of the lug acts upon the cam-surface 6°
and causes the rotation of the cluster of barrels upon the shaft d. During this
movement under the action of the incline the cluster of barrels acquires a
certain amount of momentum which causes the incline of the lug to ride along
the cam-surface and again return the barrel into its forward position.
In order that in case the force of the recoil is not sufficient to move the barrels
the required distance or in case the automatic mechanism should otherwise fail I
provide for positively rotating the barrels by hand. This is accomplished by
securing upon one end of the shaft d a disc i having clutch-teeth i'. This clutch-
disc is shewn in Figures 22, 23 and 24 which are respectively a front elevation, a
vertical section and a side elevation of the said disc.

page_text: Adjacent to this disc is arranged a second disc having clutch-teeth adapted
to engage with the teeth and formed integral with a shaft 2, as shewn most
clearly in Figures 25, 26 and 27 which are respectively a rear elevation and
sectional side elevations at right angles to each other of the said disc and shaft.
The discs i and are located in a recess in the casing of the gun, the said recesses,
as shewn, being of the same diameter as the discs so that the disc-end of the shaft
requires no bearing; the other end of the shaft is carried in a bearing kl
screwed into the end of the casing. Upon the shaft 2 is mounted a worm-wheel /
connected to the shaft by means of a spline or feather 'so that the shaft is free
to move within the worm-wheel, and between the worm-wheel and the disc j is
arranged a spring surrounding the shaft and serving to press the discj towards
the disc so that the teeth of the two discs will be in engagement. is a
worm engaging with the wheel and having secured to its shaft a crank-handle *
by means of which motion may be imparted to the worm and thus to the worm-
wheel and the discs i, j.
E
When the gun
is being rotated automatically the teeth of the disc will slip over
the teeth of the disc j, the said aise j being allowed to yield in a rearward direction
by means of the spring to allow of this movement. When, however, it is desired to
rotate the barrels by hand it will be obvious that the teeth of the disc j being
in engagement with the disc the rotation of the handle will produce the desired
movements.
The cartridges are fed to the gun from a flexible band m having a series of
spring-clips mi m' for holding the cartridges, and the band is carried upon and
moved forward by a cylinder or roller m² fixed to a spindle m³ mounted in a
bearing m and having secured to it or formed integral with it a pinion m with
which a series of teeth m, Figures 3, 4, 6 and 7, upon the periphery of the disc d'
successively engage during the rotation of the cluster of barrels.
Upon the
periphery of the cylinder m² are teeth or projections m which engage with openings
in the band between the clips m³, m', as shewn most clearly in Figure 4. The
cylinder is shewn detached in Figures 28, 29 and 30 which are respectively a
side elevation, an end elevation and a longitudinal section thereof. To prevent
the cylinder m from being rotated in the wrong direction we form in one end of
the same a series of notches m with which a pawl or a spring-catch m³, Figure 3, is
designed to engage.
"H
The cartridges are disengaged from the clips m of the band by means of spring-
arms, Figure 4, secured to the casing and projecting downwards in such a
manner that, as the band moves, the cartridges will successively ride up the said
spring-arms (which form an inclined plane) and enter the openings in the breech-
pieces. is an inclined stop which serves to prevent the cartridges from being
thrown out of the clips of the band before the breech-pieces are in the proper
position for receiving the same. n, are teeth or projections, one of which is
formed upon each breech-piece, for moving the cartridges (the heads of which lie
against the exterior casing, as indicated by the dotted circle n³ Figure 4) forward,
until they reach such a position that they will roll by gravity opposite to their
respective plungers. The bullet or projectile ends of the cartridges are held within
the openings in the breech-pieces, and so prevented from becoming jammed by
means of a rib on the inside of the casing (Figures 1, 3 and 4) the said rib
being cut away at " (Figure 4) to allow the breech-pieces to recoil. Each of the
spring-arms is provided with a shoe which bears upon the cartridge band, as
shewn in Figure 4, and so prevents the said band from lifting as the cartridges are
forced out of the clips m'.
The hammer which is located in a cylindrical chamber formed upon the casing a
and acted upon by a spring ', is cocked, during the rotary movement of the
barrels, by means of inclined planes o, (Figures 13, 14, 17 and 18) formed upon the
breech-pieces, each of which inclined planes acts upon the end of the said
hammer and forces the same back against the pressure of its spring. The hammer
is held in its cocked position by the sear p which is shewn most clearly in Figure 1

page_text: and detached in side elevation and plan in Figures 31 and 32 respectively. This
sear which is mounted upon a screw-stud pl screwed into the casing, as shown in
Figures 1 and 2, is in the form of a bell-crank lever, one end p² of which is designed
to engage with a groove p³ in the hammer whilst the other end p engages with
a slot pin the trigger-rod p sliding in a suitable recess in the casing a and having
upon its end, outside the said casing, a knob p. This trigger-rod with its knob is
represented in elevation in Figure 33 and in sectional elevation in Figure 34.
Surrounding the rod p² is a spring p², Figure 1, which normally tends to press the
trigger-rod outwards. With this arrangement it will be understood that when the
knob pis pressed inwards, the sear will be operated to disengage its end 2
from the notch of the hammer, whereby the latter is free to move forward
under the action of its spring g' to strike the firing-pin & in alignment with it.
is the handle by means of which the traversing movements of the gun are
effected, the said handle being so placed that when grasped by the left hand the
thumb can be placed upon the knob 7 for firing the gun. The rear sight which
consists of a screw-threaded bar, is passed through this handle, as shewn in
Figure 2, and is adjusted by means of a screw-nuts which is prevented from
moving longitudinally by means of a screw t, one part of the said screw entering
groove u formed upon an extension of the said nut. One side of the screw-threaded
bar is flattened, as indicated at, in order that it may be graduated for facilitating
the adjustment of the sight according to the range of the gun.
, Figure 2, indicates the aperture in the casing a through which the empty
cartridge cases are discharged, the letter indicating a case falling from the
breech-piece. is a screen which covers the cartridge band and prevents the
empty cases from falling thereon.
To enable the operation of the gun to be clearly understood I will describe the
operation of one barrel only as the function of all the other barrels is identical;
take, for instance, the barrel shewn at the upper part of Figure 3 which contains
a cartridge and has the breech closed ready for firing. If now the hammer is
released by pressing upon the knob it will strike the firing-pin e and fire the
cartridge. Owing to the recoil of the barrel and breech-piece the group of barrels
with their breech-pieces will be caused to rotate in the manner hereinbefore
described by the contact of the lug of the barrel just discharged with the
inclined surface and by momentum. During the recoil whilst the lug is acting
upon the cam-surface 65 the rear end of the pawl of the barrel just discharged
rides up the cam-surface in such a manner as to disengage the front end of the
said pawl from the recess e in its plunger e so that, during the remaining part of
the rotary motion when the lug is bearing against the cam-surface & the barrel
and breech-piece are free to move forward whilst the plunger is free to move
backwards owing to the engagement of its lug with the cam-groove 6. As the
barrel is moved around the shaft d the groove b¹ causes the withdrawal of the empty
cartridge-shell from the barrel and when the breech-piece has come opposite to
the opening w, Figure 4, the empty cartridge case will fall out of the breech-piece.
As the rotary motion is continued, the empty breech-piece comes over the cartridge
band m when, owing to the rotation of the cylinder m² carrying the said band and
to the action of the inclined surfaces of the spring-arms n, n, a cartridge will be
ifted partly into the breech-piece so that it can be caught by the adjacent
projection n. This projection during the further rotation carries the cartridge
around until it has reached such a position that the rib n³ on the casing aided by
gravity moves it into the breech-piece opposite to the plunger.
As the rotary motion continues, the plunger is pressed forward owing to the
am-groove acting upon the lug and drives the cartridge into the barrel and
he inclined surface o on the breech-piece impinges against the hammer and forces
he same back to cock it; the hammer is then released to strike the firing-pin and
xplode the cartridge. Of course when the gun is in operation all the various
perations are being performed simultaneously for the different barrels and the

page_text: hammer is cocked by the brecch-piece of the barrel succeeding that which has
just been discharged.
A gun constructed and operated in the manner hereinbefore described can be
fired at a high rate of speed without risk of the barrels being overheated as when
8 barrels are employed, as shewn in the drawings, only one is firing at a time so
that for seven eighths of their time the barrels are cooling.
In the foregoing description I have referred to the gun as having each barrel
fired by depressing the knob p' cach time that a barrel comes into position: it is
to be understood, however, that if the gun is to be fired automatically it is only
necessary to retain the trigger out of engagement with the hammer so that, imme-
diately the inclined surface o of each breech-piece passes the hammer to cock it,
the said hammer will be again free to fly forward.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. A machine gun having a group or cluster of barrels arranged around a common
axis, the said barrels being adapted to recoil and at the same time to cause the
rotation of the group of barrels by the impingement of lugs against cam-surfaces,
substantially in the manner described.
2. In a machine gun the combination with a series of recoiling barrels the
recoiling movement of which is utilized for rotating the said barrels, of mechanism
or means whereby the said barrels may also be operated by hand-power, sub-
stantially as described.
3. In a machine gun having a series of revolving barrels adapted to recoil and
the
provided with fixed breech-pieces in which the breech-bolts or plungers move,
employment of pawls pivotted upon the said breech-pieces and adapted to engage
with the breech-bolts or plungers to lock the same during the firing, the said
pivotted pawls being operated by cam-surfaces, substantially as described.
4. In a machine gun having a series of barrels adapted to rotate upon a common
axis, the employment of a cartridge belt for feeding the cartridges to the gun,
the said belt being carried upon a rotating barrel or cylinder operated by lugs
engaging with a pinion upon the cylinder shaft during the rotation of the barrels,
substantially as described.
5. In a machine gun having a series of rotating and recoiling barrels as herein-
before described, the employment of a rear sight consisting of a vertically
adjusting screw-rod flattened on one side, substantially as, and for the purpose,
described.
6. The improvements in machine guns herein before described and illustrated
in the accompanying drawings.
7. The improved machine gun consisting of the parts and constructed and
combined substantially in the manner hereinbefore described, and operating as,
and for the purposes, set forth.
Dated this 8th day of June 1892
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.