Year: 1887

page_text: Date of Application, 24th Dec., 1887
Complete Specification Left, 14th Sept., 1888
Complete Specification Accepted, 19th Oct., 1888
1 JAMES ATKINSON LONGRIDGE, of 15 Great George Street, in the City of West-
minster, Civil Engineer do hereby declare the nature of this invention to be as
follows:-
My Invention relates first to the breech screw plug or block of breech loading
ordnance.
As usually made, the meridional sectional area of the plug is constant or nearly so,
throughout that part of the plug or block at which is situated the interrupted screw
whereby the plug or block is screwed into the breech of the gun, the consequence
being that the pressure is unequally borne by the successive threads of the screw, the
first thread supporting the greater and the last, the least portion of the pressure, and
injury to the first thread frequently results from this unequal distribution of the
strain.
My first improvement has for its object to obviate this defect, and it consists in so
proportioning the amount of metal in successive portions of the length of the block
that the sectional area of the metal in the plane of each thread is proportional to the
amount of strain to bo thereby sustained, so that the total strain will be equally or
nearly equally distributed throughout the whole of the threads and all tendency to jam
or distort the first threads is avoided.
The desired end is attained by hollowing the breech block or plug, the hollow
approximating to the form of a paraboloid of which the vertex is towards the front
end of the breech block or plug and about on the same transverse plane as the first
thread of the screw.
My Invention relates secondly to the construction of cases for the cartridges used
in ordnance.
When ordinary metallic cartridge cases are used, they require to be removed from
the breech of the gun after the charge is fired, and for this purpose it is necessary to
provide the gun with an extracting apparatus.
My Invention has for its object to obviate this; and it consists in constructing the
cartridge case of a metal or metallic alloy which will be fused or volatilized by the

page_text: heat of combustion of the charge and be discharged along with the products of
combustion. For this purpose, I may use zinc, tin, lead, or an alloy of all or any
of them with bismuth or other metal, the nature of the metal or metals used and
the proportions of the alloy depending on the temperature at which fusion is
desired to take place, as will be readily understood.
The preferred construction of the cartridge case is a cylinder or drum, of which
the sides may be corrugated longitudinally to give them greater stiffness, or they
may be plain. The bottom or base is flanged and soldered or rivetted to the side.
The top is a flanged disc fitting within the sides which are longer than the intended
length of the cartridge and are notched or serrated, the V points being turned
down over the top after the case is filled, and shellac or other resinous matter being
put between to exclude moisture, the tips of the V points being then secured by a
little soft solder. Through the longitudinal axis of the case may pass a small tube also of
fusible metal or alloy, said tube being soldered in the bottom plate and extending
through the top plate over which it is turned down in the same way as the sides.
This tube is perforated with small holes at intervals in its length, in order that the
fire may be communicated from the primer nearly simultaneously throughout the
whole length of the cartridge.
When a gas check is necessary, as in the Krupp gun or when the breech plug
does not enter the boro of the gun, a copper ring of approximately | section encircles
the base of the cartridge case, the cylindrical member of the ring being parallel
on the inside to the side of the cartridge case which fits within it and slightly
conical externally so as to exactly fit a slight enlargement of the bore of the gun.
This ring which forms a perfect gas check, is left in the bore and is easily removed
after firing.
J. A. LONGRIDGE.
By A. M. & Wm. Clark,
53, Chancery Lane, London,
Patent Agents.

page_text: I, JAMES ATKINSON LONGRIDGE, of 15, Great George Street, in the City of West-
minster, Civil Engineer, 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 first to the breech screw plug or block of breech loading
ordnance of that kind in which the breech plug or block is usually made solid or
perforated with a cylindrical or nearly cylindrical hole for the stalk of the mushroom
head or firing tube.
As usually made, the transverse sectional area of the plug is constant or nearly
so throughout that part of the plug or block at which is situated the interrupted
screw whereby the plug or block is screwed into the breech of the gun, the conse-
quence being that owing to the compression of the metal caused by the powder
pressure on the breech plug, the pressure is unequally borne by the successive threads
of the screw, the first thread supporting the greater, and the last the least, portion of
the pressure, and injury to the first thread frequently results from this unequal
distribution of the strain.
My first improvement has for its object to obviate this defect; and it is illustrated
in Sheet 1 of the accompanying drawings forming part of this specification, which
represents in longitudinal section so much of the breech of a piece of ordnance
with the breech plug or screw fitted therein, as is necessary to explain my
invention.
The improvement consists in so proportioning the amount of metal in successive
portions of the length of the block A that the sectional area of the metal in the plane
of each thread a¹, a², a³, etc., is proportional to the amount of strain to be thereby
sustained, so that the total strain will be equally, or nearly equally, distributed
throughout the whole of the threads and all tendency to jam or distort the first threads
is avoided. The desired end is attained by hollowing the breech block or plug A, the
hollow B approximating, as shewn, to the form of a paraboloid, of which the vertex is
towards the front end of the breech block or plug and about on the same transverse
plane as the first thread of the screw. C is the hole in the front end of the block A in
which is received the stem of the usual mushroom head (not shewn).
My Invention relates, secondly, to the construction of cases for the cartridges used
in ordnance. This part of the invention is illustrated in Sheet 2 of the drawings
in which figure 1 is a longitudinal section, and figure 2 a plan, of the cartridge
the right-hand half shewing the case before, and the left-hand half after,
being filled. Figure 3 is a section of the base of the cartridge when provided with
a gas check ring.
case;

page_text: When ordinary metallic cartridge cases are used, they require to be removed from
the breech of the gun after the charge is fired, and for this purpose it is necessary to
provide the gun with an extracting apparatus.
My Invention has for its object to obviate this; and it consists in constructing the
cartridge case of a metal or metallic alloy which will be fused or volatilized by the
heat of combustion of the charge and be discharged along with the products of
combustion. For this purpose, I may use zinc, tin, lead, or an alloy of all or any of
them with bismuth or other metal. When strength of cartridge case is of minor
importance I prefer the following mixture:
But the nature of the metal and the proportions of its constituent parts may be
varied, according to the temperature of fusion desired and the conditions under which
the case is to be employed.
The preferred construction of the cartridge case, is a cylinder or drum C of which
the sides may be plain or they may be corrugated longitudinally, as at c, to give them
greater stiffness, the corrugations extending to within a short distance of the ends
which are left cylindrical to receive the top and bottom of the case. This cylindrical
part of the case may be a sheet bent up and rivetted or soldered, or it may be drawn
out of the solid. The bottom or baso D is cupped or flanged, as at d, so as to fit
within the cylindrical part of the sides C, the bottom D, being soldered or rivetted to
the side. The top E is a flanged disc fitting, like the bottom D, within the sides (
which are made longer than the intended length of the cartridge and are notched or
serrated, as at c¹. The top E is applied and secured after the cartridge case is filled,
by turning down the V-points of the sides over the top, shellac or other resinous
matter being put between the points and top, to exclude moisture, the tips of the
V-points being then secured by a little soft solder.
Through the longitudinal axis of the case may pass a small tube F also of fusible
metal or alloy, said tube which is flanged at bottom, passing through and being
soldered to the bottom plate D. The tube extends through the top plate E and its
upper end is notched, as at f, and turned down over the top plate and soldered thereto
in the same way as the sides. This tube F is perforated with small holes at intervals
in its length, or it may be made of wire netting, in order that the fire may be
communicated from the primer nearly simultaneously throughout the whole length of
the cartridge.
The cartridge cases above described, are suitable for use when the Du Bange
obturation is used, but the central tube is not required if the charge is composed
of prismatic or disc powder, and I do not therefore, lay any claim to such central
tube.
of the
When a gas check is necessary, as in the Krupp gun, or when the breech plug does
not enter the bore of the gun, a copper ring G, (figure 3) of approximately section,
is made to encircle the base of the cartridge case; the cylindrical member
ring being deeper than the member g¹ and parallel on the inside to the side of the
cartridge case C, which fits tightly within it, and slightly conical externally, as shewn,
so as to exactly fit a slight enlargement of the bore of the gun. This ring, which
forms a perfect gas check, is left in the bore and is easily removed after
firing.

page_text: 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
1st. Making the part of the breech screw plug or block which is in the cross-
sectional plane of the interrupted screw, with an internal cavity in the form of a
paraboloid or a form approximating thereto, so as to proportion the sectional area of
the metal opposite each thread of the screw to the strain which the thread has to
sustain, substantially as specified.
2nd. Making the cases of cartridges for ordnance, entirely of a fusible metal or
alloy which will be entirely volatilized by the heat or caused to disappear with the
products of combustion, as specified.
3rd. Constructing the cases of cartridges for ordnance, of a cylinder (corrugated or
plain) and of flanged top and bottom ends, all of fusible metal, the top being secured
by notching and turning down and soldering the upper end of the cylindrical portion,
substantially as specified.
J. A. LONGRIDGE.
By A. M. & Wm. Clark,
53, Chancery Lane, London,
Patent Agents.