Improvements in Breech Mechanism for Guns.
Year: 1893

page_text: COMPLETE SPECIFICATION.
Improvements in Breech Mechanism for Guns.
what
I, ARENT SILFVERSPARRE, of Bofors, in the County of Wermland, Kingdom of
Sweden, Engineer, do hereby declare the nature of my invention, and
manner the same is to be performed to be particularly described and ascertained in
and by the following statement :-
This invention relates to breech mechanism for guns, by means of which the
breech can be opened or closed with ease and certainty by a single movement.
In the accompanying drawings
Figure 1 is a rear view of the breech end of a gun with my improved breech
mechanism applied thereto and in its closed position.
Figure 2 is a longitudinal section on the line A B of Figure 1.
Figure 3 is a sectional plan on the line CD of Figure 1.
Figure 4 is a similar view to that shown in Figure 3 but with the breech partly
open and,
Figures 5 and 6 show details of the extracting mechanism.
Like letters of reference indicate corresponding parts in the several figures of
the drawings.
The breech screw 1 is of an ogival form, being either threaded all round or
provided with threaded segments.
The rear part of this screw is screwed into the ring-shaped edge of a cover 2
hinged on a spindle 17 at the rear part of the gun. Upon this spindle are arranged
two toothed wheels or segments 3 and 19, the former being held loosely on the
spindle while the latter is connected thereto. At one end the said spindle is con-
nected with a lever 18 terminating in a handle. The said lever is held by a
catch 21, provided with a counterweight 36 the fore-end of the catch being acted
upon by a spring pin 22 in the gun, another such spring pin 23 being also arranged
on one side of the lever 18 for causing the said lever to be grasped between it and
the catch.
In the cover 2 connected with the toothed wheel 3 is a sliding carriage 4, which
at its front has a rack 33 which gears with the toothed wheel 19 thus causing the
sliding carriage to be drawn outward through the edge of the cover when the spindle
is turned. The inner end of the sliding carriage surrounds the rear part of the
middle of the breech screw 1, formed as a toothed segment 31, and engaging with a
number of teeth 32 on the inside of the sliding carriage. The inner end of this
sliding carriage is a projecting part 34, which catches into a notch in the back of
the breech screw, and locks this screw as long as the sliding carriage is not moved
outwards. At the back of the sliding carriage on each side of the hammer 5 are
two wedge-shaped or sloping faces 24 and behind these faces upon the hammer 5
are two shoulders 25, which in the outward movement of the sliding carriage are
struck by the faces, thus cocking the hammer, which latter has a notch 27 pertaining
to the firing mechanism. The hammer 5 is arranged in the middle of the breech
screw and surrounded by a spring 6 in the usual manner.
The firing mechanism consists, as usual, of a trigger 11, moveable on a bolt 12.
On firing the gun the small arm 11⭑* of the trigger strikes against a bar 7 moveable
at right angles to the axis of the gun and pressed outward by a spring 8, the trigger
thus causes a shoulder 26 on the bar to be pressed against the hammer, where it
catches into the notch 27, when the hammer is cocked. From the trigger 11 an
arm 28 projects inward toward the centre of the barrel of the gun and this arm
engages in a notch 30 in the flange 29 at the back of the sliding carriage.
In the ring-shaped edge of the cover 2 is a bolt 13 pushed forward by a spring 14.

page_text: and in the corresponding edge of the breech screw is a notch 20, into which the
bolt is pressed as soon as the breech screw in the opening of the mechanism has
been turned and commences to be withdrawn from the gun. On the other hand,
when the mechanism is closed the bolt is pressed back by the back part of the gun.
On the circumference of the breech screw there is a longitudinal groove 16 and in
the part of the gun surrounding the breech screw is a bolt 15, which when the
breech screw has been turned, catches into the said groove and controls the breech
screw during the withdrawal of the same.
The extractor 10 (Figures 5 and 6) consists of an arm arranged at the side of the
breech screw, the said arm being provided as usual at its fore-end with a hook,
intended to grasp the edge of the cartridge-case. The back of this arm is provided
with teeth which engage with the toothed wheel 3 on the spindle 17 which when
turned withdraws the cartridge case.
The operation is-as follows:-
As soon as the gun has been fired it recoils and causes the catch 21 to swing
owing to the movement of the counterweight around its axis; the lever 18 is thus
released from the catch and is pushed outward by the spring 23 so that the catch 21
cannot engage therewith. Upon the lever being moved backward the spindle 17
with the toothed wheel 19 is turned, and the rack 33 acting upon by the latter,
draws the sliding carriage outward, thus releasing the projecting part 34 from the
recess in the breech screw 1. In the continued movement of the sliding carriage
its teeth 32 engage with the toothed segment 31 on the breech-screw, turning it
round its axis until the bolt 15 strikes against the bottom of the groove 16, the
breech screw being then unscrewed from the corresponding screw-threads in the rear
part of the gun.
During the movement of the sliding carriage the wedge-shaped faces 24 slides
against the shoulders 25, on the hammers 5, in consequence of which the latter is
pushed back, permitting the shoulder 26 on the arm 7 to catch into the notch 27 in
the hammer, which is thus held in its cocked position.
Upon the continued rotation of the spindle 17 by means of the lever 18 the
cover 2 is forced to turn around the axis of the spindle, and the breech screw
connected with the cover is thus withdrawn from the breech chamber in the rear
part of the gun. During this movement the breech screw is controlled by the bolt 15,
resting in the groove 16, and the screw is held in position by the bolt 13, which, at
the beginning of the withdrawal of the breech screw is pressed by its spring 14 into
the notch 20 in the rear end of the screw, the said notch coming opposite the bolt
when the breech screw is turned.
When the cover 2 is turned the toothed wheel 3 is also turned and withdraws the
extractor with the cartridge-case, the flange of which is grasped by the hooked end
of the extractor.
After the cartridge-case has then been removed by hand, a new cartridge is put
in, and the lever 18 is turned in the opposite direction and the cover is then turned
against the rear part of the gun, the breech screw is again introduced into the gun
and the bolt 13 is pushed out from the corresponding notch, releasing the breech
screw as soon as it has been pushed sufficiently far into the gun and the bolt 15 has
reached the upper part of the groove 16. In the continued turning of the lever 18
the teeth 32 act upon the toothed segment 31, causing the breech screw 1 to be
turned and screwed into the gun, while at the same time the wedge-shaped
faces 24 on the sliding carriage are pushed away from the corresponding
shoulders 25 on the hammer 5, which thus can move freely forward when the gun
is fired.
After the handle 18 has been turned the projecting part 34 on the sliding carriage
is pushed into its corresponding notch in the breech screw. When the handle has
reached its final position the sliding carriage has been pushed in so far that the
notch 30 comes opposite the end of the arm 28 on the trigger 11 and the trigger can
therefore be moved and the gun fired which was not possible before, because the
trigger was stopped by the flange 29 on the rear side of the sliding carriage.

page_text: As soon as the lever 18 has attained its foremost position the catch 21 engages
with it again and keeps it in its place until the gun is again fired.
If the gun misses fire or hangs fire, then the said gun does not recoil, and the
mechanism cannot therefore be opened before the lever 18 has been released from
the catch 21 by hand.
The toothed wheel 3 of the extracting mechanism, herein before described as being
firmly connected with the cover 2, ought rather to be arranged in such a manner,
that it can be unlocked from the cover, at will, whereby it becomes possible to open
the mechanism, without putting the extractor into action.
For this purpose a polygonal coupling-box 37 with clutches may be used which
is pushed on to the end of the spindle 17 into a recess of corresponding form in the
cover 2, so that the clutches 38 of the coupling-box can catch into the corresponding
notches in the toothed wheel 3 and thus force this wheel to follow the movement of
the cover.
If on the other hand the coupling-box is drawn out of its connection
with the toothed wheel, then the cover can be turned independently of the
extracting mechanism.
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. A breech mechanism for guns consisting of following parts viz. :-a breech
screw (1) of ogival form, having at the rear end a toothed segment (31) and con-
nected with a cover (2) hinged to a spindle (17) at the side of the gun, a toothed
wheel or toothed segment (19) on the said spindle and a sliding carriage (4) in the
cover, provided with teeth (32, 33) on the side facing the toothed wheel or segment,
all for the purpose of turning the spindle by means of a handle first to draw out the
sliding carriage and to unscrew the breech screw (1) and then to withdraw it from
the breech opening of the gun, and to close the mechanism again by the movement
of the lever in the opposite direction.
2. In breech mechanism for guns a breech screw of ogival form, which is either
screw-threaded all round or provided with threaded segments.
3. In the breech mechanism above described means for locking the breech
screw (1) to the cover (2) during its turning movement comprising a bolt (13)
situated in the cover and pushed forward by a spring, the fore-ends of which bolt
extends towards the back of the gun when the mechanism is closed, and a notch (20)
in the rear part of the breech screw, which notch during the turning of the screw
comes into position opposite the bolt, which under the action of its spring is pushed
into the notch, when the cover is turned from the gun.
4. In the breech mechanism above described means for controlling the breech
screw during the withdrawal from the gun consisting of a bolt (15) on the inside of
that part of the gun which surrounds the breech screw, and of a longitudinal
groove (16) made on the face of the breech screw, into which groove the bolt
enters, when the breech screw has been unscrewed from the gun.
5. In the breech mechanism above described a cocking mechanism for the hammer
consisting of two sloping faces (24) on the back of the sliding carriage (4), of a pair
of shoulders (25) corresponding with the said faces and placed on the part of the
hammer situated behind the sliding carriage, of a shoulder (26) acted upon by a
spring connected with the firing arrangement and of a corresponding notch (27) in
the hammer.
6. In the breech mechanism above described means for preventing the firing of
the charge before the mechanism has been fully closed, consisting of a flange (29)
on the rear side of the sliding carriage (4) and an arm (28) projecting from the
trigger (11) against the said Hange as long as the mechanism is not fully closed, and
of a notch (30) on the flange, which notch comes into position opposite the said arm,
when the mechanism is closed, thereby permitting the moving of the arm and of the
trigger for firing the gun.
7. In the breech mechanism above described means for preventing the danger of

page_text: hanging-fire consisting of a counterbalanced catch (21) intended to engage with the
lever (18) for working the mechanism and acted upon at its one end by a spring
which keeps it raised until in the recoil of the gun it is turned by reason of the
movement of the counterweight thus releasing the lever.
8. In the breech mechanism above described an extracting mechanism consisting
of a toothed wheel (3) on the spindle (17) of the cover (2) and eventually connected
with such cover and of an extractor (10) situated between the breech screw (1) and
the rear part of the gun and being on its side facing the toothed wheel provided
with teeth, which engage with the said wheel, thus causing the extractor to be
pushed in or out during the turning of the toothed wheel.
Dated this 6th day of January 1893.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.