An Improved Apparatus for Use in Measuring the Pressure of Gas in Guns.
Year: 1893

page_text: Date of Application, 4th Aug., 1893
Complete Specification Left, 24th Apr., 1894-Accepted, 14th July, 1894
PROVISIONAL SPECIFICATION.
An Improved Apparatus for Use in Measuring the Pressure of
Gas in Guns.
I, ALFONS CASTENHOLZ, of 76 Westendstrasse, Karlsruhe, in the Empire of
Germany, Retired Colonel and General Manager of the Deutsche Metallpatron-
enfabrik, do hereby declare the nature of this invention to be as follows:-
My invention relates to apparatus for use in measuring the pressure of gas which
in the combustion of a certain quantity of powder or other explosive material is
produced in guns.
The improved apparatus comprises a cartridge made without a base and
resembling a cartridge with a projectile; a stamp with a central bore for the firing
pin, this stamp being arranged behind the cartridge so as to permit of axial motion
and containing the firing device; and a cylinder made of a material adapted to be
upset or jumped, which bears against the said stamp, surrounds the firing pin and
is supported by an abutment. This cylinder in the rearward movement of the
said stamp caused by the action of the explosive charge, undergoes a certain
reduction in its length, from which the amount of pressure of the gas is determined
by calculation.
In carrying my said invention into practice I insert, in lieu of a cartridge with a
projectile, for which the pressure of gas produced in the interior of the same is to
be measured, a cartridge case without a base into the cartridge chamber of the
gun, the said case being provided with the full charge of such a cartridge with a
projectile. Against the rear flange of the cartridge case bears a sleeve, the joint
formed between them being made tight by means of an annular groove and tongue.
The cartridge case and sleeve are surrounded by a jacket which on the one hand
takes behind the flange of the cartridge case and can on the other band be pressed
by means of a flange on the aforesaid sleeve against the cartridge chamber. This
pressure by which the sleeve, jacket and cartridge case are forced together so as
to be gas-tight and held in their proper position relatively to the cartridge
chamber, is produced by means of a nut screwed upon the barrel or body of the
gun and having an interior collar which presses against the above-mentioned
sleeve.
In this sleeve which has the same bore as the cartridge case, is arranged a stamp
adapted to move axially and consisting of three parts, this stamp being ground
in so as to form a gas-tight joint. The tightness of the joint is further increased
or ensured by a vulcanite ring provided between the two front parts of the
stamp. The latter has in front a removable part with which it passes so far
into the cartridge case that the remaining space can take up exactly the full
charge of a cartridge with a projectile. This removable part is provided with
an anvil and vent holes and a cup for the reception of the priming cap. The
stamp has in its rear part a bore extending as far as the cup in the removable
part and serving for the reception of the firing pin.
The firing pin is arranged in a tube screwed into the before-mentioned nut
and is forced to the front in the known manner through the medium of a spring
as soon as it is liberated by a stop.
Between the stamp and the tube containing the firing pin I place a central
cylinder consisting of a material which is adapted to be upset or jumped, such
as for instance copper, a certain amount of play being left between this cylinder
and the firing vin.

page_text: The pressure of gas produced in the combustion of the explosive material forces
the stamp backwards and upsets or jumps to a certain extent the cylinder butting
against the aforesaid tube. This reduction in the length of the cylinder enables
the amount of the maximum pressure of gas which has come into action, or the
amount of the resistance produced in forcing the projectile through the bore of the
gun to be determined by calculation.
In a simplified arrangement adapted for measuring the pressure of gas in
flangeless cartridge cases I provide, instead of the case, sleeve and jacket berein-
before referred to, a jacket which may be regarded as a prolongation of the said
jacket to the chamber containing the projectile. This long jacket is energetically
pressed by a nut into the cartridge chamber, so that at the point where the powder
chamber and chamber for the projectile meet a gas-tight joint will be obtained.
The stamp remains unchanged and the long jacket is ground in to form a gas-tight
joint. This jacket is preferably made of hardened steel, whereby the enlargement
of the combustion chamber will be prevented and accuracy and uniformity in the
measurement will be ensured also in the case of very high pressures.
By reason of the complete obturation of the gas and the slight loss of pressure
through friction caused by the stamp the cylinders are upset or jumped with only
slight differences, so that by the improved apparatus the pressure of the gas is
measured with almost absolute accuracy.
Dated this 4th day of August 1893.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.
An Improved Apparatus for Use in Measuring the Pressure of
Gas in Guns.
I, ALFONS CASTENHOLZ, of 76 Westendstrasse, Karlsruhe, in the Empire of
Germany, Retired Colonel and General Manager of the Deutsche Metallpatron-
enfabrik, 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 to apparatus for use in measuring the pressure of gas which
in the combustion of a certain quantity of powder or other explosive material is
produced in guns.
The improved apparatus comprises a cartridge made without a base and
resembling a cartridge with a projectile; a stamp or plug with a central bore for
the firing pin, this stamp or plug being arranged behind the cartridge so as to
permit of axial motion and containing the firing device; and a cylinder made of a
material adapted to be upset or jumped, which bears against the said stamp or plug
surrounds the firing pin and is supported by an abutment. This cylinder in the
rearward movement of the said stamp or plug caused by the action of the explosive
charge, undergoes a certain reduction in its length, from which, the amount of the
pressure of the gas is determined by calculation.
Referring now to the accompanying drawing,
Figure 1 is a sectional view of a gun with the apparatus complete.
Figure 2 is an enlarged sectional view of the cartridge, sleeve and jacket
and
Figure 3 is a sectional view illustrating a modified form of gas pressure
apparatus.
In carrying my said invention into practice I insert, in lieu of a cartridge with a
projectile, of which the pressure of gas produced in the interior of the same is to
be measured, a cartridge case x without a base into the cartridge chamber A of

page_text: the gun see Figure 1, the said case being provided with the full charge of such
a cartridge with a projectile. Against the rear flange of the cartridge case.r
bears a sleeve 6 the joint formed between them being made tight by means of
an annular groovex and tongue, see Figure 2. The cartridge case and
sleeve b are surrounded by a jacket 9, Figures 1 and 2, which on the one hand
engages with the flange of the cartridge case and can, on the other hand, be pressed
by means of a flange on the aforesaid sleeve against the cartridge chamber..
The
pressure by which the sleeve, jacket and cartridge case are forced together so
as to be gas-tight and held in their proper position relatively to the cartridge
chamber A is produced by means of a nut a screwed upon the barrel or body of the
gun, Figure 1, and having an interior collar a' which presses against the above-
mentioned sleeve b.
**
In the sleeve b which has the same bore as the cartridge case is arranged a
stamp or plug e, Figures 1 and 2, adapted to move axially and consisting of three
parts e, e
this said stamp or plug being ground in so as to form a gas-tight.
joint. The tightness of the joint is further increased or ensured by a vulcanite
ring provided between the two front parts e* c** of the stamp or plug c.
The
latter is provided in front with a removable part c' with which it passes so far
into the cartridge case that the remaining space will take up exactly the full charge.
This removable part is provided with an anvil and vent holes and a cup c³·
for the reception of the priming cap. The stamp or plug has in its rear part a
bore extending as far as the cup in the removable part and serving for the
reception of the firing pin d.
The firing pin is arranged in a tube screwed into the before-mentioned nut a
and is actuated by the spring m as soon as it is liberated from the stop, see
Figure 1.
Between the stamp or plug c and the tube g containing the firing pin d I place a
central cylinder / made of a material which is adapted to be upset or jumped, such
as for instance copper, a certain amount of play being left between this cylinder
and the firing pin.
The pressure of gas produced in the combustion of the explosive material forces
the stamp or plug backwards and upsets or jumps to a certain extent the cylinder /
butting against the aforesaid tube g. This reduction in the length of this cylinder h
enables the amount of the maximum pressure of gas which has been brought into
action, or the amount of the resistance produced in forcing the projectile through
the bore of the gun to be determined by calculation.
The same arrangement shown in Figure 2 may also be employed for flangeless.
cartridge cases, the sleeve a being suitably fitted thereon.
Figure 3 shows a simplified arrangement of the gas pressure apparatus. Instead
of the case, sleeve b, and jacket 7 bereinbefore referred to a jacket I is provided
which may be regarded as a prolongation of the said jacket to the chamber
containing the projectile. The stamp or plug remains unchanged and the long
jacket I is ground in to form a gas-tight joint. This said jacket I is preferably
made of hardened steel, whereby the enlargement of the combustion chamber will.
be prevented and accuracy and uniformity in the measurement will be ensured even
in the case of very high pressures.
By reason of the complete obturation of the gas and the slight loss of pressure.
through friction caused by the stamp or plug the cylinders are upset or jumped
with only slight differences, so that by the improved apparatus the pressure of the
gas is measured with almost absolute accuracy.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
First. The improved apparatus for measuring the gas pressure for small arms and
cannon, characterized by a cartridge case without a base, a sleeve 6 having the
same bore and fitted in gas-tight, and a pressing stamp or plug c adapted to move.

page_text: axially therein and provided with a central firing device, which said stamp or plug
forced back by the explosive gases upsets or jumps a cylinder h.
Second. A modification of the gas pressure meter characterized in the first
claim, in which, in lieu of a cartridge case without a base and the sleeve b, is
arranged a single jacket I receiving the pressing stamp or plug adapted to move 5
axially.
Dated this 24th dar of Anmil 180.1
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.