Improvements in Cartridges.
Year: 1894

page_text: Date of Application, 11th Sept.. 1894
Complete Specification Left; 23rd Feb., 1895-Accepted, 23rd Mar., 1895
Improvements in Cartridges.
1, EDUARD RUBIN, of Thun, Switzerland, a First Lieutenant in the Swiss
Army, do hereby declare the nature of this invention to be as follows:-
In a cartridge having a charge of specific explosive power, the pressure of the
gas acting upon the projectile at the instant of the explosion of the charge, depends
on the size of the chamber of the cartridge in which the charge.is gasified, and on
the cross-sectional area of the projectile.
If this chamber be small and the cross-sectional area of the projectile also be
small, then the explosion-gases can expand only to a slight extent and slowly,
so that the initial pressure may rise to a dangerous amount; it is therefore:
necessary with ordinary cartridges to keep the amount of the charge within certain
limits.
With this
Now, in the case of cartridges according to this invention the employment
of considerable charges is. allowable with projectiles of small calibre, which enables
correspondingly greater initial velocities of the projectiles to be obtained; because
at the instant of explosion the explosion-gases increase, without appreciable
resistance, the size of the chamber in which the explosion takes place, and thus
undergo that initial expansion which is requisite to keep their pressure within the
limits imposed. This cartridge acts therefore, so to speak, as a buffer.
object the projectile is provided with a collar whose external diameter is equal to
the internal diameter of the cartridge-case, so that the projectile and the collar
together constitute a piston which is capable of moving forwards in the cartridge-
case, as a result of the explosion and almost without any resistance, through
a distance limited by the cartridge-case. The bore of the barrel of the gun is
formed in such a manner that the projectile enters the rifling of the barrel only
after it has travelled through the said distance, that is to say only after the
projectile has become separated from the collar, which is kept back by the
cartridge-case; only then does the projectile begin to experience appreciable
resistance to its onward movement.
The accompanying drawing illustrates in longitudinal section one arrangement of
cartridge according to this invention.
The projectile d is guided at its forward portion in a neck of the cartridge-case a,
and is provided with a collar c', the external diameter of which is equal to the
internal diameter of the cartridge-case. The piston consisting of the projectile d
and its collar c', is normally in contact with a projection a' which may be formed by
an internal corrugation of the cartridge-case. Initial expansion of the gases
is rendered possible in the case of this cartridge, since the piston can move at the
instant of explosion without material resistance through the distance allowed by the
space in front of it in the cartridge-case. As soon as the collar c' strikes against
the forward neck of the cartridge-case, it is left behind in the said case by the
projectile. The latter then moves into the rifling of the gun-barrel and meets the
resistance of the gun-barrel itself to its propulsion by the explosion-gases.
Dated this 11th day of September 1894.

page_text: improvements in Cartridges.
I, EDUARD RUBIN, of Thun, Switzerland, a First Lieutenant in the Swiss
Army, 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 :-
In a cartridge having a charge of specific explosive power, the pressure of the
gas acting upon the projectile at the instant of the explosion of the charge, depends
on the size of the chamber of the cartridge in which the charge is gasified, and on
the cross-sectional area of the projectile.
If this chamber be small and the cross-sectional area of the projectile also be
small, then the explosion-gases can expand only to a slight extent and slowly,
so that the initial pressure may rise to a dangerous amount; it is therefore
necessary with ordinary cartridges to keep the amount of the charge within certain
limits.
Now, in the case of cartridges according to this invention, the employment
of considerable charges is allowable with projectiles of small calibre, which enables
correspondingly greater initial velocities of the projectiles to be obtained, because
at the instant of explosion the explosion-gases increase, without appreciable
resistance, the size of the chamber in which the explosion takes place, and thus
undergo that initial expansion which is requisite to keep their pressure within the
limits imposed. This cartridge acts therefore, so to speak, as a buffer. With this
object the projectile is provided with a collar whose external diameter is equal to
the internal diameter of the cartridge-case, so that the projectile and the collar
together constitute a piston which is capable of moving forwards in the cartridge-
case, as a result of the explosion and almost without any resistance, through a
distance limited by the cartridge-case. The bore of the barrel of the gun is formed
in such a manner that the projectile enters the rifling of the barrel only after it has
travelled through the said distance, that is to say, only after the projectile has
become separated from the collar, which is kept back by the cartridge-case; it is
not till then that the projectile begins to experience appreciable resistance to its
onward movement.
The drawing filed with my Provisional Specification illustrates in longitudinal
section a construction of cartridge according to this invention.
The projectile d is guided at its forward portion in a neck of the cartridge-case a,
and is provided with a collar c¹ the external diameter of which is equal to the
internal diameter of the cartridge-case. The piston consisting of the projectile d
and its collar c', is normally in contact with a projection a', which may be formed
by an internal corrugation of the cartridge-case. Initial expansion of the gases is
rendered possible in the case of this cartridge since the piston can move at the
instant of explosion without material resistance through the distance allowed by the
space in front of it in the cartridge-case. As soon as the collar e' strikes against
the forward neck of the cartridge-case, it is left behind in the said case by the
projectile. The latter then moves into the rifling of the gun-barrel and meets the
resistance of the gun-barrel itself to its propulsion by the explosion gases.
Having now particularly described and ascertained the nature of the said inveu-
tion and in what manner the same is to be performed 1 declare that what 1
claim is :-
1. A ball cartridge wherein the projectile is provided at its inner end with
an enlargement adapted on the firing of the cartridge to move axially in the
explosion chamber of the cartridge case after the manner of a piston and so increase

page_text: the size of such chamber before the inner end of the projectile passes clear of it
substantially as herein described.
2. A ball cartridge in which the projectile is provided with a detachable collar c¹
so as to form a piston adapted to slide in the cartridge case and so increase the size
of the explosion chamber when the cartridge is fired substantially as described and
shown for the purpose specified.
Dated this 23rd day of February 1895.
For the Applicant,
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C., Chartered Patent Agent.