Improvements in Breech-loading Fire Arms.
Year: 1890

page_text: Date of Application, 6th Nov., 1890
Complete Specification Left, 5th Sept., 1891-Accepted, 10th Oct.. 1891
PROVISIONAL SPECIFICATION.
Improvements in Breech-loading Fire Arms.
I, OSKAR WILLIAM BERGMAN, of Gothenburg, in the Kingdom of Sweden,
Lieutenant in the Royal Swedish Artillery, do hereby declare the nature of this
invention to be as follows:-
My invention relates to machine guns and similar fire arms and has for its object
to provide improved means for feeding the cartridges to the barrels either from a
magazine or when carried by a belt.
In carrying out my invention I make use of a worm or screw the groove forming
the thread of which is adapted to more or less receive the cartridges and I place
my worm or screw at such an angle to the barrel that the cartridges shall be in
line with the barrel when lying in the groove of the worm.
Any suitable means may be employed for rotating the worm.
Dated the 6th day of November 1890.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Breech-loading Fire Arms.
I, OSKAR WILLIAM BERGMAN, of Gothenburg, in the Kingdom of Sweden,
Lieutenant in the Royal Swedish Artillery, 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 invention relates to machine guns and similar fire arms, and has for its object
to provide improved means for feeding the cartridges to the barrels either from a
belt or from a magazine.
In carrying out my invention I make use of a worm or screw the groove forming
the thread of which is adapted to more or less receive the cartridges, and I place
my worm or screw at such an angle to the barrel that the cartridges shall be in
line with the barrel when lying in the groove of the worm.
Any suitable means may be employed for rotating the worm.
To enable my invention to be fully understood I will describe the same in con-
nection with a machine gun, the barrel of which is designed to recoil during the
discharge, and in which such recoil is utilized for rotating the worm or screw.
In the accompanying drawings:-
Figure 1 is a longitudinal section of so much of a machine gun of the class
referred to as is necessary to illustrate the application of my invention thereto, the
cartridges being conveyed to the gun by means of a belt ; and,
Figure 2 is a plan of part of the same:
Figures 3 and 4 are sections on the lines x and y y respectively of Figure 2:
Figure 5 is a view illustrating a detail of construction.
Figure 6 is a view similar to Figure 3 shewing the application of my invention
or conveying cartridges from a magazine.
Similar letters of reference indicate corresponding parts in the several figures.
a indicates the mounting of the gun, the barrel, and c the breech-block or
lunger.
d is the box in which my improved cartridge feeding mechanism is located, the
aid box being hinged to the gun mounting so that access to the interior thereof can
e obtained. e, e, Figure 2, indicate parts of the hinge.,

page_text: f is my cartridge feeding screw or worm which is supported in the box d by
means of an axle, and projects through an opening in the bottom of the said box,
the said worm being arranged at such an angle, for instance, as shewn in dotted
lines in Figure 2, that the cartridges which lie between the threads thereof will be
parallel with the axis of the barrel.
indicates the cartridge carrying belt, and i, i the cartridges therein.
j is a bar adapted to slide in grooves j', in the top of the box d and having at
one end a projection in which is formed a slot with which a pink formed
upon a lug or extension ¹ from the barrel b engages. The slot ³ is provided to
allow the box d to be opened whatever may be the position of the parts.
Upon one side of the sliding-bar j is a lug 1, in a slot of which engages a
pin m on one end of a bell crank lever m' pivotted to the top of the box d by
a screw m². n is a plate mounted upon and capable of sliding relatively to the
lever m', the said plate being retained in its proper position relatively to the
lever, at one end by the screw or stud m² which is passed through a slot n¹ in
the said plate, and at the other end by a stud n² formed integral with the said
plate and extending down through a slot n³ in the lever m' and into a cam-
groove in the shank of the worm as hereinafter described. Upon the upper
side of the plate n is a stud n which extends into a slot n in the top of the
box d and parallel with the axis of the worm f
With this arrangement of parts it will be understood that when, during the recoil
of the barrel, the sliding-bar is moved, the lever m¹ will also be moved, the move-
ment of the plate n relatively to the said lever m¹ perinitting the stud n* to travel
in the groove n³.
o is the cam-groove which is formed in the shank of the worm f, the shape
of the said groove being clearly shewn in Figure 5 which represents a develop-
ment of a portion of the said worm in which the said groove is formed. It
will be understood that as the stud n' of the plate n enters the said cam-groove
and the stud n¹ travels in a straight line, the worm will be caused to rotate,
that is to say, as the barrel recoils after the discharge of the gun, the stud n
will move the distance allowed by the slot n³, as indicated in Figure 2 (where
nindicates the position of the said pin in the slot n after the recoil) and the
stud n will travel from the part o¹ to the part 2 of the groove o thereby
rotating the worm f half a revolution. When the barrel again moves forward
the said stud n' moves from the part of back to the part o' of the groove o in
the direction indicated by the arrows in Figure 5, thereby completing the
rotation of the worm.
་
In practice the pitch of the thread of the worm must be such that one revolu-
tion thereof will suffice to feed a cartridge into line with the barrel.
When the worm is to be employed for feeding cartridges from a magazine, as
shewn in Figure 6, I make the worm of sufficient length to extend across the
magazine, as shewn, the cartridges in the said magazine being arranged in rows, the
distance between which corresponds to the pitch of the worm.
p indicates the bottom of the magazine which is raised by springs in order to
press the cartridges towards the worm, or the magazine may be placed above the
worm so that the weight of the said cartridges will keep them in contact with the
worm.
The worm shewn in Figure 6 may be rotated by means of mechanism such as that
hereinbefore described or by any other suitable means.
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. Feeding cartridges to the barrel or barrels of breech loading fire arms by
means of a worm, substantially in the manner described.
2. In'a fire arm a rotating worm for feeding cartridges to the barrel or barrels
either through the medium of a belt or from a magazine, substantially as described,

page_text: In a pre arm having a rotating worm for feeding the cartridges to the barrel
or barrels, the employment of a lever such as m' and a plate sliding thereon and
having two projections or studs, one of which extends into a cam-groove in the
shank of the worm, for transforming the longitudinal motion of the barrel into
rotary motion of the worm, substantially as described.
4. The improved cartridge feed mechanism for fire arms, consisting of the parts
constructed and combined substantially as described with reference to Figures 1
to 5 and Figure 6 of the accompanying drawings and operating as, and for the
purposes, set forth.
Dated the 5th day of September 1891.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.