Improvements in Gas Checks for Breechloading Ordnance.
Year: 1892

page_text: ate of Application, 25th Aug., 1892-Accepted, 15th Oct., 1992.
COMPLETE SPECIFICATION.
Improvements in Gas Checks for Breechloading Ordnance.
SAMUEL SEABURY, Lieutenant United States Navy, residing at 59 Avenue D.,
Bayonne (formerly Bergen Point) in the County of Hudson and State of New
Jersey, United States of America, 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 is applicable both to that class of breech-loading ordnance in
which the removable breech block is inserted into and withdrawn from the gun by
movements in line with the bore or parallel with the axis thereof, as, for example,
the mutilated screw breech block, and to that class in which the breech is opened
and closed by the movement of the breech block transverse to the bore. One
feature of my invention also provides for quick and easy adaptation of a breech-
block of the class hereinbefore first mentioned to the use of either fixed
ammunition, which has its own gas check, or to the use of such cartridges as
have no gas-check.
Fig. 1 represents an axial section of the breech portion of a cannon having a
mutilated screw breech block, to which one of my gas checks is applied and
Fig. 2 is a face view of the said breech-block, and gas check.
Fig. 3 represents an axial section of the breech portion of a gun having a
similar breech block, illustrating the method in which my gas check is applied to
a gun, to provide for the use of either loose or fixed ammunition, the gas check
being detachable for the use of the fixed ammunition; and
Fig. 4 is a face view of the breech block and gas check corresponding with
Figure 3.
Fig. 5 represents an axial section illustrating a slight modification of what is
shown in Fig. 3.
Fig. 6 is a detail view to be hereinafter explained.
Fig. 7 represents an axial section of a breech block of the same kind as that
shown in Fig. 1, but with a gas check somewhat modified.
Fig. 8 represents a similar section, on a larger scale, of some of the parts shown
in Fig. 7.
Fig. 9 is a view corresponding with Fig. 8, illustrating a modification of that
form of my invention shown in Figures 7 and 8.
Fig. 10 represents an axial section, in a horizontal direction, of the breech
portion of a cannon having a transversely sliding breech-block, to which one of
my gas checks is applied.
Similar letters of reference designate corresponding parts in all the figures.
In all the figures, A. designates the body of the cannon, B the breech-block, Ca
gas check disc, and D a central bolt for securing the gas check disc to the
breech block.
In all the figures, except Figures 6 and 10, 6 designates the mutilated screw.
threads of the breech block.
The gas check shown in Figs. 1, 3, and 4, is composed of several thin plates
of sheet steel or other suitable metal. The said disc is of such circumference,
that in its normal condition its outer edge, which is presented circumferentially,
fits easily or loosely to the bore of the cannon, and has, between the said outer
edge and the central openings provided for the bolt D, an annular bulge in a
forward direction, and between the back of its so bulged part and the face of the
breech block there is left a sufficient space c¹ (shown black in Figs. 1 and 3), to
permit the so-bulged part to be pressed backwards, and the disc to be, to a
certain extent, flattened by the pressure resulting from the firing of the charge of

page_text: the gun, the effect of so pressing back the so-bulged part, and flattening the disc,
being to produce such radial and circumferential expansion of the latter as to bring
the edges of the several plates of which the disc is composed gas-tight against the
bore of the gun. In the example shown in Figs. 1 and 2, which is a gun for the
use only of loose cartridges.which have no gas check, the front part of the breech
block is represented as entering a little way within the bore of the gun, forward of
the screw threaded counterbore or breech block seat, and thereby serving as a
rearward support to the outer marginal portion of the gas check disc C, and in
this example the bolt D, passing through the disc C, and through the centre of
the breech block, is provided with a head which overlaps the inner edges of the
disc, and the said bolt has, on its rear portion, a screw-thread for the reception of
a nut d, by the screwing up of which the inner marginal portion of the said disc is
brought tightly up against the face of the breech block. The said bolt has a
central bore which constitutes a vent for firing the gun, and its rear end is
counterbored to receive a primer.
In the example shown in Figs. 3 and 4, the counter bore or breech block
seat, and the breech block proper B, are constructed in a manner common to
breech loading guns of the same kind, for the use of fixed ammunition, that is to
say, with a space a (see Fig. 3) for the flange of the cartridge shell, and the so
constructed breech-block is provided with a concentric nose plate E, which is
applied to it when loose cartridges are to be used, but taken away when fixed
ammunition is to be used. The gas check disc C, which is like that shown in
Figs. 1 and 2, is applied in front of this nose plate E, instead of directly to the
face of the breech block.
In Fig. 3, the face of this nose plate is represented as constructed like the face
of the breech block shown in Fig. 1, with a space c¹ behind the bulged part of the
disc C, and the said nose plate is represented as having its front part constructed
to enter and fit the bore proper of the gun when the breech block is closed, and
so to constitute a rearward support for the marginal portions of the said disc. In
this example, the hollow bolt D of the gas check, which secures the disc C, passes
through the nose plate also, and secures that too to the breech block, but the said
bolt, instead of passing through the breech block, as in the first example, is screwed
into the breech block."
To prevent the nose plate E from turning, it has screwed into it a dowel-pin f
(see Fig. 3), which enters a hole provided for it in the face of the breechblock,
and to prevent the unscrewing of the bolt D, a screw pin is screwed through one
side of the breech block, to enter a notch in the said bolt. The bolt D.is repre-
sented in Fig. 3 as counterbored, in front, to a taper form to receive a primer
cup, which is fitted to said taper counterbore with a mutilated screw thread h',
by which it may be tightly screwed up in place, but which provides for its easy
removal and the breech block is represented as bored centrally in rear of the
said bolt D, to receive the firing pin I, which enters the said primer cup / through
the hollow bolt D.
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e of its
The face of the solid breech-block B shown in Fig. 1, and the face of the nose
plate E, which is practically a part of the breech-block shown in Fig. 3, are cach
represented as having an annular forward bulge i, behind the bulge
respective gas check disc, but the said bulge i is made less prominent or full than
the bulge c of the disc, in order that the space c¹ may be preserved between the
face of the block or nose plate and the disc. This bulge i on the face of the block
is to prevent the bulged parts of the disc C from being so much pressed back by
the pressure resulting from the firing of the charge, that they would not recover
themselves and allow the disc to resume its normal condition after the explosion.
In order to guard against cutting out or injury of the bore of the gun by the
outer edges of the gas-check disc. C, I. provide, as shown in Figs. 1 and 3, in the
rear part of the bore, where this disc is received, a hardened steel bushing ring,
the gun being counterbored in front of the breech block seat to receive the said
ring, which is tightly driven into its place, and the interior of which is of a calibre

page_text: corresponding with the bore of the gun. To protect the central bolt D, which
may be made of soft steel, from the inner edge of the gas-check disc, I place, as
shown in Figs. 1 and 3, around that part of the bolt which receives the said disc, a
collar of hardened steel.
.
The gun shown in Fig. 5 corresponds exactly with that shown in Figs. 3 and 4,
except as to the particular form of gas-check disc C, which, in Fig. 5, is composed
of a single plate, the edges of which are cupped and turned back over a portion of
the nose plate E, which is reduced in circumference to receive it, the turned-in or
cupped portion of the said disc having such an external circumference as to permit
the said disc to pass freely with the nose plate into the bore of the gun. This
disc C shown in Fig. 5, like those before described with reference to Figs. 1 and 3,
has a forward bulge c and a space c¹ left behind the said bulge between it and the
face of the nose plate or breech block, so that when the said disc receives the
pressure resulting from the discharge of the gun, its bulged part may be forced
back, with the effect of expanding said disc against the bore, as described with
reference to the disc in Figures 1 and 3.
When it is desired to use the gun shown in Figs. 3, 4, and .5, for fixed
ammunition, it is only necessary, first, to unscrew and take out the central hollow
bolt, and then remove the nose plate E. The tapped hole provided in the breech
block for the said bolt D, is then plugged up flush with the face of the block by
a plug m, such as is shown in Figure 6, which represents a longitudinal section
of the said block and the surrounding parts of the block. The said plug is bored
to receive the forward end of the firing pin I, which passes through it to strike the
primer in the centre of the head of the cartridge shell.
In the example illustrated in Figs. 7 and 8, the breech block B has its face of a
circumference larger than the bore a' of the gun, and the gas-check disc C is of
the same, or about the same, size as the face of the breech block, and consequently
large enough to overlap the bore, and to permit its marginal portion to be received
between the face of the breech block and the front faces of the breech block.seat.
A space is provided in the breech block seat, around the forward portion of the
breech block and the outer circumference of the disc C. The said disc C is.
represented as substantially flat, except in the marginal portion, which is received
between the face of the breech block and the faces of the breech block seat, which
portion has a rearward bulge, to form an annular groove in its face for the
reception of a packing ring or annular gasket n, a corresponding groove being
formed in the faces for the reception of the said ring or gasket.
The marginal portion of the face of the breech block is hollowed out to conform
to the marginal portion of the back of the disc C. The portion of the face of the
breech block which is opposite the face of the bore a¹ of the gun, and opposite the
flat portion of the disc C, is slightly dished, or concave, as indicated at c' in
Figures 1 and 2, to permit the backward bulge of the said portion of the said
disc, when it is subjected to pressure produced on its face by the firing of
the gun.
The ring or gasket n may be of any suitable elastic or plastic material, but I
prefer to make it of asbestos and grease, such as is now commonly used in some of
the gas checks for breech-loading ordnance. The said ring, which may be of
round or square transverse section, may be attached to the face of the disc, or
placed in the groove in the faces of the breech block seat.
The central bolt D by which the gas check disc C is attached to the breech
block, in this example (represented in Figs. 7 & 8) is made with a head at its front
end, and is fitted behind the said head with a flanged collar J, the flange of:
which is on the front end of this collar between the bolt head and the disc C.
and the portion of the said collar behind the flange is fitted to the central
opening in the disc, and enters a counterborer, which is provided in the front of
the breech block around the central opening provided for the bolt D. The bolt D
is rigidly secured in the breech block by being provided with a shoulder which
abuts against the back of the counterbore r, and with a nut d fitted to the screw

page_text: thread on its rear portion, the said nut serving to hold the said shoulder against
the back of the counterbore. Room is left in the back of the counterbore for a
slight sliding movement of the collar along the bolt.
22
When the gun illustrated in Figs. 7 and 8 is loaded, the breech block is screwed
up tightly, and the ring or gasket and the marginal portion of the disc C will be
tightly clamped between the breech-block and the faces of the breech block seat;
but when the gun is fired, the pressure will act upon the flanged collar J, and the
portion of the disc outside of said collar, to press back into the cavity of the
breech block the portion of the said disc opposite the said cavity. The disc will
then assume the character of an annular lever, the fulcrum of which is the
circular edge formed around the cavity c' in the breech-block, and by this lever-
like action the marginal portion of the disc, outside of said edge, will be pressed
forward, and caused to compress the gasket or packing ring so tightly between the
breech block and the faces of the breech block seat, as to preclude the possibility
of any leakage of gas.
After the discharge of the gun, the elasticity of the dise produces the return of
the flanged collar J to the normal condition shown in Figs. 7 and 8.
In order to prevent any leakage of gas between the flanged collar J and the
bolt D, a groove » (see Figs. 7 and 8) is so turned in the face of said collar as to
form a very thin and flexible annular lip around the said bolt. Any gas getting
between the head of the bolt and the said flange entering the said groove,
produces such contraction of the edge of said lip around the bolt, as to form a
gas-tight joint.
The modification of my invention illustrated in Figure 9, differs from that shewn
in Figs. 7 and 8 in having no packing-ring or gasket.
In this example the metal disc is represented as fat all the way to its
circumference, but in other respects is like the first example.
Its marginal portion is, as in the previous modification, screwed up between the
face of the breech-block and the face of the seat. The lever-like action of
the said disc, above described as produced by the pressure of the gases, forces the
face of the marginal portion of the said disc hard and tight against the faces, and
tends to produce a gas-tight joint between them. In the example shown in
Fig. 10, with the transversely sliding breech-block, the central portion of the
dise C is like that shown in Fig. 9, except that its central portion is cupped to
receive within it the collar and the head of the bolt D, and the said block is
counterbored from its face around the bore provided for the said bolt, to receive
the said cup, so that the said bolt head and collar are so countersunk within the
breech block, as not to interfere with its sliding movement. In this example, the
packing ring or gasket n is square in its transverse section, and is received and
retained within a groove of corresponding form in front of the breech block seat,
and the marginal portion of the disc is flat, but the same lever-like action described
with reference to Figs. 7 and 8 occurs when the pressure of the gases acts upon the
disc; and the marginal portion of the disc is made to compress the gasket or
packing ring n, and to make a tight joint between the breech block and
the bore a'.
In adapting my invention to the sliding breech block, the packing ring or gasket
may sometimes be dispensed with, and the margin of the disc may operate in
direct contact with the face s or front of the breech block seat, as it does in the
example Figs. 7 and 8.
It is possible, also, that in some cases the collar J may be dispensed with, and
the central bolt pass directly through the disc C.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is :-
1. The combination with the breech block of the centrally attached gas-check
disc, the outer marginal portion of which has a bearing against the said block,

page_text: and between which and the said block, there is a space, as c¹, within the circum-
ference of said bearing, substantially as herein described with reference to
Figures 1, 3, 5, 7, 8, 9, 10.
2. The combination with the breech-block of à breech loading gun, of a gas
check disc secured to the face of said block, and having a forward bulge behind
which there is a space between the said disc and said face, substantially as and for.
the purpose herein set forth with reference to Figures, 1, 3, 5.
3. The combination with a breechloading gun and a breech block fitted thereto,
and entering it from the rear, of a gas check disc secured to the face of said block,
and having its outer edge presented circumferentially, and also having a forwardly
bulged portion behind which there is a space into which said bulged portion can
be forced back to expand said circumferentially presented edge against the bore of
the gun, substantially as herein set forth with reference to Figures 1 and 3.
4. The combination in a breech loading gun, of a breech block having a bulged
face and a gas check disc secured to said face & having a forward bulge fuller
than the bulge of said face, whereby a space is provided between the bulged
portion of said face and said disc, substantially as and for the purpose herein set
forth with reference to Figures 1 and 3.
5. The combination with a breech-loading gun and a breech block fitted
thereto, and entering it from the rear, of a removable nose plate and attached gas
check disc substantially as herein described, to provide for the use of either fixed
or loose ammunition, as may be desired.
6. The combination, substantially as herein described with reference to
Figs. 7, 8, 9, 10, of a breech-loading gun, a breech block therefor having a
portion of its face concave, and a gas-check disc, the marginal portion of which
disc adapted to overlap the bore of the gun, is received between the front face of
the breech block seat and the marginal portion of the face of the breech block,
and the other portion of which disc, nearer to its centre, is free to move backwards
within the concave of the breech block face, for the purpose of exerting a forward
pressure on its marginal portion, as herein set forth.
7. The combination with a breech-loading gun and a breech block therefor,
having a portion of its face concave, of a disc C and a flanged collar J fitted to a
central opening in said disc, and a central bolt for attaching said disc and collar
to the breech block, the said disc being adapted to overlap the bore of the gun,
and to be received between the face of the breech block and the front face of the
breech-block seat, and the collar and the central portion of said disc being free to
move backward on said bolt, substantially as and for the purpose herein set forth,
with reference to Figs. 7, 8, 9, 10.
8. The combination with a breech loading gun and a breech block therefor, of
a gas check disc which is attached to said breech block, and the marginal portion
of which, adapted to overlap the bore of the gun, is received between the face of
the breechblock and the front of the breech block seat, and a gasket or packing
ring applied between the front of the said disc, and the front of the breech block
seat, substantially as herein set forth, with reference to Figs. 7, 8, 9, 10,
9. The combination with the breech-block, of a gas check disc, a central bolt
for attaching said disc to the face of the breech block, and a collar fitted to said
bolt, and constructed with a flexible lip,, to prevent the escape of gas around said
bolt, substantially as herein set forth.
Dated this 25th day of August 1892.
NEWTON & SON,
Agents for the Applicant.