Year: 1898

page_text: We, LA SOCIÉTÉ FRANÇAISE DES MUNITIONS DE CHASSE, DE TIR & DE GUERRE,
of 30, Rue Notre Dame des Victoires, Paris, in the Republic of France, do
hereby declare the nature of this invention to be as follows:-
-
Metallic cartridge cases are subjected, during firing, to very great pressure,
exceeding, sometimes, 3,500 kgs. per square centimeter; under this pressure,
the bottom of the case resting upon the breech of the gun becomes crushed, its
thickness becomes diminished and its diameter increased.
The invention is illustrated in the accompanying drawing the figures of
which are hereinafter referred to.
The recess for the priming cap a a¹ (Figure 1), carried in the bottom of the
case, also increases in diameter, and if the priming cap which is contained
therein, is not possessed of sufficient elasticity, it does not increase in diameter
in the same ratio.
A small annular gap will therefore be formed around the priming cap; the
compressed gases rush through this opening and give rise to leakages which
injure the breach of the gun and may be a source of danger to the operator.
Further, the cap, being no longer supported in the recess, falls out of its place
into the mechanism of the weapon and thus stops its action.
In Figure 1 the dotted line cd shows the interior of the case before firing,
and the full line below it is the same after firing, when its thickness has been
diminished by the pressure of the gases. The dotted line a ef al shows the
recess for the priming cap before firing, and the full line which crosses it
represents the same recess after deformation.
The softer the metal, the greater will be the deformation of the end of the
case, thus with aluminium, the effect produced is much more marked than with
hard brass..
With aluminium it is almost impossible to avoid this deformation; therefore,
to obviate the inconvenience resulting therefrom, it is necessary to have recourse
to various contrivances.
The object of the present invention is a special arrangement by which the
above described inconvenience may be obviated.
As shown in Figure 2, I arrange a circular lip or projection m, m¹ around

page_text: the recess of the priming cap. During the firing, and under the pressure of
the gases, this lip which rests on the smooth surface of the breech of the gun,
will be crushed until the bottom oo' of the case in its turn bears upon the
breech.
The lip or projection mm², Figure 2, will therefore be forced into the annular
space (Figure 2), of triangular section between the recess, and the rounded
angle of the priming cap, and fills this space as shown in Figure 3.
The back of the priming cap is grasped by the metal thus compressed, and
forms a joint the tightness of which is increased by pressure.
Instead of allowing the lip mm to project as shown in Figure 2, and leaving
the work of forcing the said lip into the recess to the pressure of the powder
gases, I prefer to do this at the same time and by the same operation as putting
the priming cap in place, I thus give it at once the shape shown in Figure 4.
In this figure the circular boss before its compression is shown in dotted lines.
It will be understood that this arrangement can be applied to all socket
cartridge cases, whatever may be their shape and size.
Dated this 15th day of Welune 1808
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicants.
We, LA SOCIÉTÉ FRANÇAIS DES MUNITIONS DE CHASSE, DE TIR & DE GUERRE,
of 30, Rue Notre Dame des Victoires, Paris, in the Republic of France, 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:-
Metallic cartridge cases are subjected, during firing, to very great pressure,
exceeding, sometimes, 3,500 kgs. per square centimeter; under this pressure,
the bottom of the case resting upon the breech of the gun becomes crushed, its
thickness becomes diminished and its diameter increased.
The invention is illustrated in the drawings left with
Specification, the figures of which are hereinafter referred to.
our Provisional
The recess for the priming cap a a¹ (Figure 1) carried in the bottom of the
case, also increases in diameter, and if the priming cap which is contained
therein, is not possessed of sufficient elasticity, it does not increase in diameter
in the same ratio.
A small annular gap will therefore be formed around the priming cap; the
compressed gases rush through this opening and give rise to leakages which
injure the breach of the gun and may be a source of danger to the operator.
Further, the cap, being no longer supported in the recess, falls out of its place
into the mechanism of the weapon and thus stops its action.
In Figure 1 the dotted line ed shows the interior of the case before firing
and the full line below it is the same after firing, when its thickness has been
diminished by the pressure of the gases. The dotted lino a ef a¹ shows the
recess for the priming cap before firing, and the full line which crosses it
represents the same recess after deformation.
The softer the material, the greater will be the deformation of the end of the

page_text: case; thus with aluminium, the effect produced is much more marked than with.
hard brass.
With aluminium it is almost impossible to avoid this deformation; therefore,
to obviate the inconvenience resulting therefrom, it is necessary to have recourse
to various contrivances.
The object of the present invention is a special arrangement by which the
above described inconvenience may be obviated.
As shown in Figure 2, we arrange a circular lip or projection mm' around
the recess of the priming cap. During the firing, and under the pressure of
the gases, this lip which rests on the smooth surface of the breech of the gun,
will be crushed until the bottom o¹ of the case in its turn bears upon the
breech.
The lip or projection mm³ Figure 2, will therefore be forced into the annular
space nn (Figure 2) of triangular section between the recess and the rounded
angle of the priming cap and fills this space as shown in Figure 3.
The back of the priming cap is therefore held by the material thus compressed,
and forms a joint, the tightness of which is increased by pressure.
Instead of allowing the lip m m¹ to project as shown in Figure 2 and leaving
the work of forcing the said lip into the recess to the pressure of the powder
gases, we prefer to effect this at the same time, and by the same operation as
putting the priming cap in place. We thus give it at once the shape shown in
Figure 4. In this figure the circular boss before its compression is shown in
dotted lines.
It will be understood that this arrangement can be applied to all socket
cartridge cases, whatever may be their shape, size or material.
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. The arrangement around the recess for the priming cap in socket cases
for military and other purposes of a circular boss, which when forced inward
by the pressure of the gases from the powder, forms a joint which prevents the
leakage of gas, as above described.
2. The arrangement referred to in Claim 1, in which the circular boss is
forced inward at the time of putting the priming cap into place, to obtain at
once the joint above described.
3. The application of the arrangement referred to in Claims 1 and 2 to socket
cases of aluminium or any other metal, and also to cases of other material than
metal.
Dated this 10th day of October 1808
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicants.