Year: 1887

page_text: Communicated from abroad by THEODORE YATES, of Milwaukee, in the State of
Wisconsin, United States of America, Colonel (retired) of United States Army.]
I, ALFRED JULIUS BOULT, of 323 High Holborn in the County of Middlesex, M.I.M.E.
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 relates to breech loading ordnance, and the invention consists in a
novel breech closing mechanism, and in gas checks for use with the same, as hereinafter
more fully described.
Referring to the accompanying drawings,-
Figure 1 is a top plan view with the breech portion shown in section.
Figure 2 is a bottom plan view showing the lever for operating the breech closing
clamps.
Figure 3 is a longitudinal central vertical section.
Figure
4 is a similar section, with the breech mechanism detached.
Figure 5 is a transverse horizontal section showing one form of gas check, and
Figure 6 is a vertical section of another form of gas check shown detached.
Figure 7 is a front face view of the obturating plate, shown detached, and
Figure 8 is a diagram, illustrating the lines of strain on the gun and breech clamps
when fired.
The object of this invention is to produce a breech loading gun that shall be strong,
simple in construction, easy to manipulate in use, that can be fired rapidly without
danger of being rendered inoperative by the heating and expansion of the parts.
This system of breech mechanism can be applied to solid or built up guns, and can
be used for converting muzzle loaders to breech loaders.
In the drawings,
A represents the chase or front portion of the barrel or body of the gun, and B the
rear or breech portion of the same.
Upon the breech portion near its rear end, a series of annular shoulders g are
formed, as shown in Figures, 1, 2, 3, and 4, there being two or more in number. In
making new guns it is preferable to make these shoulders 9, to project beyond the

page_text: exterior wall of the body, though they may be formed by turning grooves in the
exterior surfaco if preferred, this latter being better adapted to the alteration of
muzzle loaders, especially in those cases where the caliber is reduced by the insertion
of a steel tube as is now frequently done with cast iron guns.
Two clamps CC are then provided, in the form of semi-circular shells of such size
as to fit over and enclose the breech portion of the gun, as shown in Figures, 1, 2, 3,
and 8, they being made to fit over the rear end of the gun and the bore, when closed,
as represented in Figures, 2, 3, and 8. These clamps are provided on their inner
walls with a series of annular shoulders f corresponding in number and location with
the shoulders g on the gun,-the abutting faces of the shoulders f and g, being formed
at right angles to the axial line of the gun, while their other or opposite faces are
beveled or inclined, as shown clearly in Figure 3.
These clamps C, C, are pivoted to the body of the gun by two central vertical pivots
or bolts b, one at the top and the other at the under side, as shown in Figures 2 and 3,
so that they can be swung laterally to close or open the breech, they requiring to be
moved each but little more than half the diameter of the board to open the breech as
shown in Figure 1, and of course the same distance in the reverse direction to close
the breech.
In order to open and close the clamps a lever F is provided which as shown in
Figure 2; is pivoted on a stud or bolt m, which as shown in Figure 3, is rigidly
secured to the body of the gun at its under side and projects below the face of the
clamps C, C. This lever is curved as shown, in Figure 2, and has a slot in it on
opposite sides of the pivot m, a pin projecting from the under side of one of the
clamps engaging in one of the slots, and a similar pin projecting from the other clamp
engaging in the other slot, so that by swinging the lever F in one direction it causes
the clamps to swing outward at their rear end, and to open the breech, and when
moved in the reverse direction it throws the clamps together, to close the breech.
In order to prevent the clamps from being accidentally opened by the moving of
the gun in hauling it about, or by the rolling or pitching of the vessel, if on ship
board, to one of the clamps a spring catch d is secured the hook on which is arranged
to engage in a recess in the other clamp, as shown in Figures 2 and 3, this catch
being preferably located on the rear end of the clamps, a little above the bore of the
gun, as shown in Figure 3, so as to be out of the way in charging the gun. This
catch may be modified in form, and may be located wherever desired. Inasmuch as
the two clamps are of uniform weight, and are connected one to the other by the
pins n and lever F, it will be seen that even when the gun is turned more or less on
its side, the one clamp is counterbalanced by the other, and that therefore there is
very little tendency for them to swing to and fro, and hence the catch d is not required
to be made very heavy, its function being merely to hold the clamps together when
the gun is moved or hauled, and not being relied on to hold them against the force of
the charge, for a reason hereinafter explained.
9
The clamps are made of such a size that when closed there will be a space of about
one-twentieth of an inch between their inner faces and the exterior surface of the body
of the gun, for the two-fold purpose of allowing for the expansion of the gun in firing,
and to prevent the vibration of the metal of the gun when fired, from being transmitted
direct to the clamps, as would be the case, if they were in close contact with the body
of the gun at all points. It is necessary however, that where the pivots b are located
the clamps should bear on the gun in order to prevent them from sagging when
swung apart, as if they were permitted to sagg, the shoulders fand would strike
when brought back, and prevent the clamps from closing readily. So too, that portion
of the clamps in rear of the bore should fit snugly against the plate I, hereinafter
described, to hold it firmly in place. So too, the shoulders fand 9 should fit snugly
against each other when the clamps are closed, and this can be readily accomplished,
because as will be seen, the clamps when being opened, will swing in the arc of a
circle of which the pivots 6 are the centre, thus causing the shoulders f to move
forward as well as outward away from the shoulders 9 when opened, and to swing
back against them when closed, as will be readily seen by examining Figure 1.

page_text: ing one drag
Figure o it will be seen that all the rearward force exerted
by the charge, will be applied to the clamps within the circle of the bore of the gun,
and that the strain from thence to the shoulders g will be transmitted in the directions
indicated by the dotted lines, and that consequently the force exerted on the clamps
at the rear of the bore will tend to draw the clamps in the direction indicated by the
dotted lines and thereby cause them to clasp or hug the body of the gun just in
proportion to the rearward force exerted by the charge in firing the gun. It will
therefore be seen, that there is no tendency of the clamps C, C, to open or separate
when the gun is fired, as might at first sight be supposed, but that on the contrary
they are caused to clasp the body of the gun all the tighter. It is for this reason
that neither the lever F, nor the latch d is depended upon to hold the clamps closed.
In fact the gun can be, and has been fired with both the lever and the latch
detached.
To close the rear end of the bore, an obturating plate I is provided which consists
of a solid plate of steel or other suitable material, and preferably hinged to the rear
end of the gun below the bore, as shown in Figures 3 and 4, its edges being beveled
to enable it to swing into and out of the rear end of the bore, which is correspondingly
beveled, as shown more clearly in Figure 5. The pivot o, on which the plate I is
hinged, should be in rear of the centre of gravity of plate I, so that there will be no
tendency of the latter to fall back out of place when closed. A small projection r is
formed on the rear side of the plate I, to come in contact with the end of the gun
when opened, as shown in dotted lines in Figure 3, and prevent it from dropping far
enough to cause the vent plug to strike the body of the gun.
A vent pluge is inserted at the centre of the obturating plate I, it being of sufficient
length to project slightly beyond the outer face of the clamps when the latter are
closed, as shown in Figures 1 and 3,-there being of course a notch or recess in the
adjoining edges of the clamps CC at that point for the vent plug to fit in when the
parts are closed. This vent plug e also serves as a handle for opening and closing
the plate I.
Various styles of gas checks may be used with this breech mechanism. One form
consists of a cup shaped disk t, shown in section and detached in Figure 6, and in
place in Figure 3. It may be secured to the plate I by a nut c on the inner end of
the vent plug e which as shown projects through a hole in the centre of the disc t,
for that purpose. By removing the nut, the disk t, can be removed, and a new one
substituted whenever desired. This gas check or disk t may be made of steel, brass,
compressed fibre, or any suitable material.
In Figure 4 is represented the charge of powder as being enclosed in a case G,
composed of any suitable material, and which is designed to act as a gas check. In
order to cause the rear end of this case G to be forced out into the angle and pack
the joint around the edge of the plate I, without rupturing the case at that point,
its rear end is made concave, as shown in Figure 4, so that the force of the gas acting
on the convex side of the base of the case and forcing it back against the face of
plate I, will cause it to expand laterally from the centre, and thus crowd or force
the material of the case outward into the angle and prevent it from being ruptured
at that point.
In Figure 5 is illustrated another form of gas check and which will probably be
found most convenient in use. This consists of a ring E, preferably of steel set in
an annular recess in the rear end of the chamber, its front edge being beveled or
reduced in thickness as shown, so as to be expanded by the force of the gas, and be
thereby held tight against the surrounding wall of the recess to prevent the escape
of gas at that point. The internal diameter of this ring is as large or a little larger
than the bore, so as to permit the charge to be readily inserted through it. On its
rear face this ring is provided with one or more ✓ shaped grooves.
In the face of the plate I is set, in an annular recess, a ring v of copper, or other
suitable metal, in such manner as to project slightly beyond the face of the plate I,
and having on its face one or more shaped projections intended to enter into, and

page_text: the corresponding
closed.
shaped groove in the face of the ring when the plate 1 is
This relation of the parts is obviously possible only in cases when one is moved
directly from, or to the other. No lateral or sliding motion, as in the Krupp system
being tolerable.
The powder gases acting upon the beveled or curved inner face of the ring E, not
only forces its front edge outward, but at the same time presses it backward, against
the packing ring V of plate I, forcing all surfaces into close contact, and thus insuring
a more perfect check to the escape of gas at that point..
So too, in guns having the interrupted screw, or plug of any kind, the ring E may
be used, with the ring V, inserted in the face, or front end of the screw, or plug. This
would be more simple and cheaper than the devices in use, and would add strength
to the system because, the screw, or plug, would be enlarged in diameter to equal the
exterior diameter of the ring E, and thus add largely to the bearing surfaces of the
threads on the screw plug.
It it obvious that the ring might be dispensed with, and the V shaped projections
be made on the face of the breech closing plate I (or on the face of any similar breech
closing device used instead of the plate as above suggested) but it is preferable to use
the ring so that it may be removed, and be replaced with a new one whenever
desired.
The ring E is designed to remain in place until it becomes necessary to replace it
with a new one, and so too, of the packing ring v.
If preferred the gas check may consist of an annular lip made integral with the
obturating plate I, but the inventor prefers to make it separate from the plate to
enable it to be changed from time to time as may be necessary, without changing the
plate.
It may be remarked that by using a suitable concave breech closing plug, to be
inserted in rear of the charge, and which will be held in place by the clamps in the
same manner as the obturating plate I is, the plate I may be dispensed with, but it is
preferable to use the plate with the gas check as shown in Figures 4 or 5, as he
considers it more convenient and as giving better results.
So too, the vent tube instead of being applied to the plate I at the rear, may, if
preferred, be inserted in the body of the gun at any point of the chamber desired,
and thus be made to ignite the charge at, or near its front, but with the improved
kinds of powder now used it is preferable to locate it as shown.
In order to exclude rain etcetera, one of the clamps C may have secured to it a
lip or thin strip of metal arranged to shut over the other clamp to any desired
extent, this lip extending from the upper pivot 6 backward over the point and down
over the rear end as far as necessary.
By arranging the clamps to swing laterally, the liability of obstruction to the closing
of the breech, by the accidental entrance of any debris or material of any kind is
greatly obviated, as the opening being in a vertical plane, the tendency will be for any
object to pass through and drop out below.
By locating the lever F at the underside, it is not only out of the way, but its
pivot m which may be made of any required size with a suitable head, is brought
into the proper position to rest upon the head of the elevating screw and which will
not interfere with the opening and closing of the clamps, or the operating of the
lever.
The advantages of this breech system are first, its great simplicity, consisting as it
does of but few parts, simple in form and easily made; second its great strength,-
for as will be seen, the shoulders g and being on the exterior of the gun, will present
a much greater area of bearing surface than do the threads of the interrupted screw or
the transverse wedge now generally used, and the extent of surface of the clamps
enables them to be made comparatively thin on their sides, and yet have the
necessary strength. It affords a greater length of bore for a given length of gun than
any other system, and it gives to the gun when completed a symmetrical appearance.

page_text: One of its greatest advantages however, is, the ease and rapidity with which the breech
mechanism can be operated, owing first, to its simplicity, and second to the fact that
the parts are not caused to jam or bind and stick fast by the expansion of the gun
during rapid firing. It will also be observed that the strain which is usually brought
to bear on the interior portion of the gun to hold the breech plug in place, in this is
transferred to the exterior, and that the only longtitudinal strain on the interior is
that due to the friction of the shot in passing through the bore of the gun, and which
with a properly prepared projectile may be greatly reduced.
This system of breech mechanism is well adapted to the alteration of muzzle
loading to breech loading guns, especially cast iron or similar solid guns, and which
at the present time it is thought desirable to line with a steel tube, as it enables the
tube to be inserted without screw threads, by simply forming on it one or more shoulders
to prevent forward movement of the same in the gun, and enables the shoulders g to
be formed by simply turning two or more grooves in the surface of the breech portion.
Having now particularly described and ascertained the nature of the said invention
and in what manner the same is to be performed, as communicated to me by my
foreign correspondent, I declare that what I claim is :-
1. The combination in a breech loading gun, of the barrel or body of the gun
provided with the annular shoulders g, and the breech closing clamps C, C, pivoted
to the body, and provided with the internal annular shoulders f, said parts being
constructed and arranged to operate, substantially as described.
2. The combination in a breech loading gun, of the body or barrel, the pivoted
clamps C, C, and the obturating plate I, substantially as shown and described.
3. In combination with the body or barrel of a gun, the pivoted clamps C, C,
and the pivoted lever F for opening and closing the clamps, substantially as
described.
4. In combination with the clamps C, C, pivoted to the body of the gun, the spring
catch d or equivalent device for holding the clamps together, substantially as
described.
5. The combination in a breech loading gun, of the expansion ring E, and a breech
closing device, provided with a corresponding packing ring v, the abutting faces of
said rings being provided with one or more interlocking projections and grooves,
substantially as and for the purpose set forth.
6. The combination of the body or barrel, with the clamps CC, and the obturating
plate 1 provided with a vent plug e, said clamps and plate both being pivoted or hinged
to the body of the gun, substantially as and for the purpose set forth.
W. P. THOMPSON & Co.,
Agents for the Applicant.