Improvements relating to Projectiles for Ordnance.
Year: 1898

page_text: PROVISIONAL SPECIFICATION.
Improvements relating to Projectiles for Ordnance.
We, HIRAM STEVENS MAXIM, Chevalier de la Legion d'Honneur, Civil and
Mechanical Engineer, and LIEUTENANT ARTHUR TREVOR DAWSON, late of the
Royal Navy, both of 29, Victoria Street, in the County of London, do hereby
declare the nature of this invention to be as follows:-
Our invention relates to projectiles provided with means for preventing or
diminishing the erosive effects of the explosive upon the bore of a gun when
heavy charges are used therein.
The Specifications of former Letters Patent No. 680 A.D. 1890 and No. 28,093
A.J). 1896 describe projectiles of this class and our present improvements con-
sist in modifications of the devices therein described. The projectiles are
described in the said specifications as provided at the base with a cap or disc
so arranged in combination with a plastic ring or gas check that, at the moment
of the discharge of the gun, the gas-check will be subjected to greater pressure,
per square inch of its area, than that existing in the gun at the rear of the
projectile.
Our present invention is designed to provide projectiles, especially those for
heavy guns, with a ring or gas check which, while sufficiently plastic to adapt
itself to the bore of the gun, will have greater stability and will be capable of
resisting a greater shearing stress than the rings formed of wax, plumbago and
asbestos heretofore used. The said invention is also designed to provide a more
effectual manner of compressing the plastic ring than any heretofore known.
According to our present invention instead of the disc or cap heretofore applied
to the base of the projectile we use an annular base piece or collar screwed
upon the base of the projectile. That is to say the end of the projectile has its
diameter reduced to form a boss which is screw threaded on its periphery to
receive the said annular piece, the direction of the screw thread being opposite
to that of the rifling of the gun. The annular piece is preferably corrugated or
dished between its central and peripheral portion to give it elasticity. Its
peripheral portion projects forward into contact with the gas check or plastic
ring and it may or may not be large enough in diameter to engage with the
rifling of the gun. The said collar is preferably formed of soft copper and of
such a shape and thickness that, under the pressure that exists behind when
the gun is fired, it will be deformed and forced forward against the gas check,
causing the compression of the latter as above described.
Our gas check is made as follows:-That is to say we take a ring or two or
more rings of copper or other suitable wire around each of which we coil or wind
asbestos yarn. The said rings are then bound together by asbestos or other
suitable material. The ring thus formed is then saturated with wax mixed with
a small quantity of plumbago or similar substance and then placed in a mould
and subjected to great hydraulic or other pressure to give the plastic ring the
exact shape required. The said ring is then coated with pure plumbago and

page_text: copper-plated. This compound ring or gas-check may be adapted to new guns
or to guns in which the bore has been enlarged by erosion.
The thickness of the copper-plating can be varied as required, that is to say
for projectiles that are to be used with old guns it should have a considerable
thickness to enable it to resist a severe shearing stress but for projectiles to be
used in new guns it may be of comparatively slight thickness.
These rings can be made to take the place of what is commonly known as an
augmenting strip for ensuring the rotation of a projectile in a gun in which
the bore has been worn or enlarged by use.*
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicants.
Improvements relating to Projectiles for Ordnance.
"
We, HIRAM STEVENS MAXIM, Chevalier de la Legion d'Honneur, Civil and
Mechanical Engineer, and LIEUTENANT ARTHUR TREVOR. DAWSON, late of the
Royal Navy, both of 28, Victoria Street, in the County of London, do hereby
declare the nature of this invention, and in what. manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement:-
This invention relates to projectiles provided with means for preventing or
diminishing the erosive effects of the explosite upon the bore of a gun when
heavy charges are used therein and has special reference to projectiles of the kind
in which the base is provided with a cap or disc so arranged in combination
with a plastic ring or gas check that at the moment of, the discharge of the
gun the gas-check will be subjected to greater pressure, than that existing in
the gun at the rear of the projectile.
Our present invention is designed to provide projectiles, especially those for
heavy guns, with a ring or gas check, which. while sufficiently plastic to adapt
itself to the bore of the gun, will have greater stability and will be capable of
resisting a greater shearing stress than the rings formed of wax, plumbago and
asbestos heretofore used. The said invention is also designed to provide for com-
pressing the plastic ring by the gas pressure in a more effectual manner than
heretofore.
According to our invention instead of the cap or disc applied to the base of
the projectile by means of a detachable screw, we use an annular base piece or
collar which is applied to a boss specially formed for its reception on the base
of the projectile. The said annular base piece or collar is retained on the said
base in a position that enables its peripheral portion to lie in contact with the
gas check or plastic ring and said annular base piece or collar may or may not
be large enough in diameter to engage with the rifling of the gun. The said
annular base piece is preferably formed of soft copper and of such a shape and
thickness that, under the pressure that exists behind when the gun is fired, it
will by its deformation or displacement be forced forward against the gas check,
causing compression of the latter and a firm application of its periphery against
the bore of the gun as is well understood. Our gas check comprises a ring or
two or more rings of copper or other suitable wire embedded in asbestos and
saturated with a mixture of wax and plumbago or similar substance, the said
gas check being placed in a mould and subjected to great hydraulic (or other

page_text: pressure to give it the proper shape required The said gas check is then covered
or coated with metal, preferably copper.
In order that our said invention may be clearly understood and readily carried
into effect we will describe the same more fully with reference, to the accompany-
ing eight figures of drawings which illustrate sectional views showing a variety
of ways of applying our improvements. Figure 1 illustrates the whole of the
rear portion of the projectile, but the remaining figures (viz:-Figures 2 to 8)
shew only so much of the rear end of the projectile, the annular base piece and
the plastic ring as is necessary for a proper comprehension of our improvements.
In all these figures A is the projectile and a the boss at the base thereof; B is
the annular base piece or collar; C the plastic ring or gas check; and D the
driving band.
Referring more particularly to Figure 1 the periphery of the boss a is screw
threaded to receive the corresponding screw threaded portion of the annular
piece or collar B, the direction of the screw threads being opposite to that of
the rifling of the gun. The said annular piece or collar B is dished at 6¹ to
impart elasticity to said collar and to form the forwardly projecting peripheral
portion or flange b2 which lies directly in contact with the plastic ring C. This
ring is constructed of copper wires c embedded in asbestos saturated with wax
and plumbago and afterwards compressed and coated or covered with metal
as above stated. The diameter of the projectile is diminished at a¹ so that the
flange 6 of the annular piece B can act upon the plastic ring C without the
necessity of the diameter of said annular piece being made greater than
the diameter of the driving band D of the projectile. In some cases however
the diameter of the said annular piece B may be large enough to engage with the
rifling of the gun as already stated. We prefer to construct the driving band D
with an angular flange d which is preferably corrugated as shewn and serves,
when the projectile is to be used in a gun in which the bore has been enlarged
by erosion, to prevent the projectile from entering the bore too far when load-
ing. The plastic ring C is formed with a shoulder e¹ to fit the corresponding
shoulder formed by diminishing the diameter of the projectile at a¹ as already
explained, such shoulder effectually preventing the plastic ring from shifting
forwardly when acted upon by the flange of the annular piece B.
The plastic ring is in the above described construction unprovided with the
metallic coating or covering but in Figures 2, and 4 such coating or covering
is shewn on the ring. In Figure 2 it consists of numerous convolutions of thin
wire wound around the circumference of the ring; in Figures 3 and 4 it consists of
a casing enclosing the ring on all of its sides except that which lies in direct
contact with the projectile. In these examples the metallic coating or covering
may be applied to the ring by electro-deposition; or a thin casing of sheet metal
of the proper shape and dimensions may be made and be applied to the said
ring in any appropriate manner. The plastic ring is in Figure 4 made wider
than that shewn in the previous figures so as to overlap the rear edge of the
band D). In other respects the construction of the parts shewn in Figures 2, 3
and 4 is similar to that illustrated in Figure 1.
In Figure 5 the aforesaid annular piece B has its peripheral portion 2 formed
with an annular recess 63 which serves the double purpose of partially supporting
the plastic ring C and of a flange for acting on the said ring when the explosion
of the powder charge in the gun takes place. In this case the reduction of the
diameter of the projectile as at a¹ in the preceding figures is unnecessary.
In Figure 6 the annular piece B and the driving band D are formed in one
piece and instead of providing the annular piece with screw threads to engage
with corresponding screw threads on the boss a of the projectile, we form the
latter with a recess a² to receive a correspondingly shaped flange b on the annular
piece B. The said piece B is dished at 6' in an analogous manner to that already.

page_text: illustrated in Figures 1 to 4 so as to form a flange be for bearing against the plastic
ring which in this example is entirely supported by the said piece B.
In Figure 7 the annular piece B has a bent or flanged portion 65 which is
adapted to enter a. recess a² in the boss a of the projectile. The plastic ring C
is in this instance arranged in an analogous manner to that illustrated in
Figures 1 to 3.
In all of the foregoing constructions the pressure of gas acting behind the
annular piece B has to crush or deform the latter before the plastic ring C can
be compressed sufficiently to force it radially outward against the bore of the
gun. In some cases we prefer to so mount the annular piece B upon the boss a
thal the initial compression of the ring C is not dependent upon the deforma-
tion of the annular piece but upon its forward displacement as illustrated in
Figure 8 so that at the first manifestation of gas pressure in the
gun behind
the projectile the said annular piece will be immediately acted upon and so cause
the plastic ring to be squeezed outwardly against the bore of the gun with a
pressure superior to that of the gas pressure, thereby effectually checking the
passage of the gas past the plastic ring even before the annular piece has been
deformed. For this purpose the said boss a is provided with a copper or brass
ring a³ upon which the said annular piece B is mounted to slide. This ring a³
is flanged at each end as shewn at a a, the flange a preventing the annular
piece from becoming detached from the projectile and the flange a serving to
enter a corresponding recess in the projectile and thereby secure the ring in
place. If desired the projectile may be formed with an annular recess a in
its base to provide for an extended forward movement of said annular piece B
when acted upon by the gas pressure. In some cases the said ring a³ may be
dispensed with, especially if the projectile be made of untempered steel. A
Hange, to occupy the position of the flange at, would then be formed or provided
on the boss to keep the annular piece in place. The annular piece must however
in this case be tightly fitted to the projectile with no space between. The said
annular piece B does not require to be held on the boss a. with any considerable
degree of force, because, from the instant the projectile is set in motion on firing
the gun until it strikes the target, there is a tendency of the annular piece B
to move forward and hug the base of the projectile.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that
what we claim is: --
1. A gas-check consisting of wire coils or rings embedded in plastic material
substantially as described.
2. A plastic ring or gas-check coated or covered with metal substantially as
and for the purpose described.
3. An annular base-piece or collar mounted on a boss at the base of the
projectile substantially as described and adapted to act in conjunction with a
plastic ring or gas-check for the purpose specified.
4. The combination with the annular base piece and the plastic ring or gas-
check of a driving band constructed as and for the purpose described.
5. A projectile provided with the annular piece B and the plastic ring C con-
structed and arranged to operate substantially as. and for the purpose described
with reference to one or other of the figures of the accompanying drawings.
Dated this 21st day of October 1898.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicants.