IMPROVEMENTS IN METAL CARTRIDGE CASES FOR ORDNANCE AND IN THE MODE OF MANUFACTURING THE SAME
Year: 1884

page_text: I, CHARLES DENTON ABEL of No .28 Southampton Buildings, Chancery Lànè
in the county of Middlesex Consulting Engineer and Patent Agent, do hereby
declare the nature of the said invention for "IMPROVEMENTS IN METAL CARTRIDGE
CASES FOR ORDNANCE AND IN THE MODE OF MANUFACTURING THE SAME" to be
as follows:-
The us
use of metal cartridge cases for ordnance of large calibre offers several
considerable advantages as compared with the ordinary cartridge bags of textile
fabric, both as regards the construction of the gun and the manipulation and
service thereof. Thus the metal cartridge cases effect a perfect gas tight closure
between the cartridge chamber and the breech closing mechanism, rendering special
packing rings or plates unnecessary. Furthermore, percussion firing can be
employed, thus obviating the use of friction tubes, with vent screw, vent guard, &c
which are liable to so many defects; also, the deposit of residues from the charge
in the cartridge, chamber is prevented and by the use of suitable plugs for closing
the cartridge cases, the cleansing of the chamber for the projectile and the rifled
part of the bore can be effected, thus obviating the sponging process.
The metal cartridge cases that form the subject of the present invention are
comparatively thin relatively to their size, and consequently of light weight, but at
the same time they are very tough and strong owing to the method of manu-
facturing the same. By this means the limbers are not loaded to a materially
greater extent than heretofore, and the cases can be used repeatedly in target
practice. The plugs enclose the powder at the mouth of the case hermetically
against atmospheric and other external influences, and the firing devices are
introduced in such manner as to effect the hermetic closing. of the firing aperture,
while at the same time they can be readily removed and changed without
requiring the charge of the cartridge to be first emptied. As is well known, the
method at present employed for manufacturing metal cartridge cases for small guns,
such as revolver guns and mountain guns is based, firstly, on the use of discs or
washers of metal, the thickness of which bears a definite proportion to the base of
the cartridge case to, be produced, the finished, base, being as thick as, or even

page_text: thicker than the disc itself. Secondly; pressing and drawing operations for
gradually reducing the cases from larger to smaller diameters and at the same time
setting up the metal of the base in the direction from the circumference to the
centre. Thirdly; forming the sides of the case only out of the part of the disc
that is turned up at the first stamping operation. Thus in this method of manu-
facture, not only is the thickness of the base maintained in the first stages, but
during the extension of the tubular part its thickness is even increased by setting
up in order to afford the necessary thickness of rim, and for forming the cap
chamber. Also, in working up the metal, the part where the base joins the
tubular part is repeatedly drawn, while the base remains unaltered, so that the
metal is most liable to weakness at that point, causing frequent cracks, which
render the cases useless. Increasing the strength of metal at that point and
. making the transit from base to tubular part more gradual does not obviate this
defect, as although the cracks may not, in the first instance extend right through,
they will gradually do so on repeated use.
"
:
According to the present invention the above named defects are obviated by
causing all the metal of the disc that is not required to produce a certain thickness
of base with the cap chamber and rim to be forced by repeated pressure at
successive stages into the cylindrical part, the gradual flow of metal at successive
stages from the base first into the rim and thence into the cylindrical part pro-
ducing a fibrous formation whereby the point of transition from the base into the
cylindrical part is greatly strengthened against cracking or tearing.
The accompanying drawings shew the improved method of manufacture in its
various stages.
From. the thick metal disc or washer, fig. 1, is first produced by stamping the
usual cup shaped blank, which, by the first pressing in dies is converted into the
Bbape fig. 2.
The cap chamber is here already produced in general outline out of the. metal of
the base, the surrounding metal being to a certain extent forced radially outwards.
This preliminary formation of the cap chamber might also be effected in the flat
disc fig. 1 which might afterwards be stamped into the cup shape.
By the following pressings, shewn at figs. 3 and 4, the metal is more and more
displaced from the base into the rim, the diameter of the base being thereby
increased and bulged outwards while the thickness thereof is decreased.
From the bulge or swell thus formed, the material is caused by drawing to pass
gradually into the cylindrical part of the case, producing sectional profiles as shewn
at figs. 5, 6 and 7, which shew how the base becomes gradually reduced in
thickness while the metal is caused in successive stages to pass from the same
'under formation of fibre first into the periphery and thence into the cylindrical
part, sufficient metal being, however left at the periphery to form the rim.
Thus, at fig. 5, the bulge or swell previously formed is about to be forced up into
the cylindrical part while at fig. 6, another bulge has been formed by forcing. .more
metal from the base outwards, which bulge has at fig. 7 been, in its turn, forced up
into the cylindrical part.
The rim is also produced in an analogous manner, that is to say, the metal is
gradually forced from the inside to the outside as shewn at fig. 8, the inner
surface of the base being shaped by a die so that in pressing the metal into the
rim, it shall not flow back again into the central part of the base. The metal in the
latter is at this stage compressed to such an extent as to offer great resistance, so
that the softer metal in the bulge can, during the next pressing only escape
outwards. Without this method of pressing the bulge or swell would be liable to
escape both inwardly and outwardly, thereby producing a thickening of the base
again. It will be readily understood that the cartridge case may have to be
subjected to a greater number of successive pressings than those shewn on the
drawings when of large dimensions.
Fig. 9 shews the completed cartridge case. It will be readily understood how
by the gradual forcing of the metal from the base into the cylindrical part of the

page_text: metal will be converted from à granular or crystalline structure into a fibrous
condition, so that by such fibrous formation, any unequal straining of the several
parts, and consequently the production of weak places or cracks in the neighbour-
hood of the rim will be prevented.
This method of manufacture also has the advantage that discs of any desired
thickness can be used as whatever thickness may be taken it will always be reduced
to the prescribed thickness for the base, the surplus metal being forced into the
rim and thence into the cylindrical part, which is also reduced by drawing to the
required thickness, the excess in length being afterwards cut off.
In determining the thickness of the disc therefore at most the formation of
the cap chamber and the weight of the finished case have to be considered, so that
the size of the discs can be determined very accurately with a view to the
economical distribution of the metal. Of course, considerably greater pressure will
be required for producing cartridge cases with thin bases from thick discs, than is
necessary for producing them from thin discs as heretofore practised..
ABEL & IMRAY,
Agents for the Applicant,
28, Southampton Buildings,
London, W.C.

page_text: .
ז་ -
I, CHARLES DENTON ABEL, of No 28 Southampton Buildings, Chancery Lane
in the County of Middlesex, Consulting Engineer and Patent Agent, do hereby
declare the nature of my invention for "IMPROVEMENTS IN METAL CARTRIDGE
CASES FOR ORDNANCE, AND IN THE MODE OF MANUFACTURING THE SAME" and
in what manner the same is to be performed, to be particularly, described and
ascertained in and by the following statement :-
The use of metal cartridge cases for ordnance of large calibre offers several
considerable advantages as compared with the ordinary cartridge bags of textile
fabric, both as regards the construction of the gun and the manipulation and service
thereof. Thus the metal cartridge cases effect a perfect gas tight closure between
the cartridge chamber and the breech closing mechanism, rendering special packing
rings or plates unnecessary. Furthermore, percussion firing can be employed, thus
obviating the use of friction tubes, with vent screw, vent guard &c, which are
liable to so many defects; also, the deposit of residues from the charge in the
cartridge chamber is prevented, and by the use of suitable plugs for closing the
cartridge cases, the cleansing of the chamber for the projectile and the rifled part
of the bore can be effected, thus obviating the sponging process.
•
The metal cartridge cases that form the subject of the present invention, are
comparatively thin relatively to their size, and consequently of light weight, but at
the same time they are very tough and strong owing to the method of manufac-
turing the same. By this means the limbers are not loaded to a materially greater
extent, than heretofore, and the cases can be used repeatedly in target practice.
The plugs enclose the powder at the mouth of the case hermetically against atmo-
spheric and other external influences, and the firing devices are introduced in such
manner as to effect the hermetic closing of the firing aperture while at the same
time they can be readily removed and changed, without requiring the charge of
the cartridge to be first emptied.
Such firing devices must be specially constructed with a view to protect the
fulminate from external influences, to insure its certain ignition on firing and to
prevent accidental ignition in careless handling.
As is well known, the method at present employed for manufacturing metal
cartridge cases for small guns, such as revolver guns and mountain guns, is based,
firstly, on the use of dies or washers of metal, the thickness of which bears a
definite proportion to the base of the cartridge case to be produced, the finished
base being as thick as or even thicker than the disc itself. Secondly, pressing and
drawing operations for gradually reducing the cases from larger to smaller diameters,
and at the same time setting up the metal of the base in the direction from the
circumference to the centre. Thirdly, forming the sides of the case only out of the
part of the disc that is turned up at the first stamping operation.
Thus in this method of manufacture, not only is the thickness of the base main-
tained in the first stages, but during the extension of the tubular part its thickness
is even increased by setting up in order to afford the necessary thickness of rim,
and for forming the cap chamber. Also, in working up the metal, the part where
the base joins the tubular part is repeatedly drawn while the base remains unaltered,
so that the metal is most liable to weakness at that point, causing frequent cracks
which render the case useless. Increasing the strength of metal at that point, and

page_text: making the transit from base to tubular part more gradual does not obviate this
defect, as although the cracks may not in the first 'instance extend "right through,
they will gradually do so on repeated use.
It will be evident that in employing this method for the manufacture of cartridge
cases of large calibre, such as field guns and heavy ordnance, that the metal blank
must be taken of such thickness as to furnish, the metal for the cap chamber and
the rim of the case, consequently the base must retain the thickness of the blank
and the whole of the cylindrical part of the casing must be formed out of the metal
of the rim turned up on the blank. This would require the blank. to be of con-
siderable thickness and would cause the weight of the case to be very great, so
that such cartridge cases could not.be used for ordnance of large calibre, on account
of the great load they would put upon the limbers.
According to the present invention the above named defects are obviated by
causing all the metal of the blank that is not required to produce a certain thickness
of base, with the cap chamber and rim, to be forced by repeated pressure at
successive stages into the cylindrical part, the gradual flow of metal at successive
stages from the base first into the rim and thence into the cylindrical part pro-
ducing a fibrous formation, whereby the point of transition from the base into the
cylindrical part is greatly strengthened against cracking or tearing.
The accompanying drawings, shew the improved method of manufacture in its
various stages.
From the thick metal disc or blank a Fig. 1 is first produced by stamping
the usual cup shaped blank b, which by the first pressing in dies is converted into
the shape Fig. 2. The cap chamber c is here already produced in. general outline
out of the metal of the base, the surrounding metal being, to a certain extent,
forced radially outwards.
By the following pressings, shewn at Figs. 3 and 4, the metal is more and more
displaced from the base into the rim, the diameter of the base being thereby
increased and bulged outwards; while the thickness thereof is decreased.
The forcing of the metal from the centre of the blank to the outer part can.
also be partly or wholly effected before forming the rim thereon,, as shewn at
Figs 1a to 14.
The formation of the cap chamber can also be effected before, during or after the.
first pressing, or one of the first pressings of the plate, and in order to preserve the
metal from deterioration this may be effected in several stages as at Figs. 1b to 1d;
this can also be done in the first described process at Figs. to 4, in which case for
instance the complete cap chamber would only be formed at the stage Fig 4, while
in Figs. 2 and 3 the preliminary formation as shewn in dotted lines would be
produced.
To facilitate the turning up of the rim of the cup, there may be formed in the
dise a either before, during or after the first pressing (or one of the first pressings)
an annular groove e Figs. 14 to 1d, which groove, by forming a bulge in the metal
beyond it, will furnish the metal for producing the cylindrical part 6 Fig 1e, in
the most convenient form.
From the bulge or swell thus formed, the material is caused by drawing, to pass
gradually into the cylindrical part of the case, producing successively sectional
profiles as shewn at Figs. 5, 6, and 7, which shew how the base becomes gradually
reduced in thickness, while the metal is caused in successive stages, to pass from
the same under formation of fibre first into the periphery and thence into the
cylindrical part, sufficient metal being however left at the periphery to form
the rim.
c
Thus at Fig. 5 the bulge or swell previously formed is about to be forced up
into, the cylindrical part while at Fig. 6, another bulge has been formed by forcing
more metal from the base outwards, which bulge has, at Fig. 7, been in its turn
forced up into the cylindrical part.
The rim is also produced in an analogous manner, that is to say, the metal
is gradually forced from the inside to the outside as shown at Fig. 8, the inner

page_text: surface of the base being shaped by a die so that in pressing the metal into the
rim, it shall not flow back again into the central part of the base. The metal in
the latter is at this stage compressed to such an extent as to offer great resistance,
50 that the softer metal in the bulge can, during the next pressing only escape
outwards. Without this method of pressing, the bulge or swell would be liable to
escape both inwardly and outwardly, thereby producing a thickening of the base
again.
It will be readily understood that the cartridge case may have to be subjected
to a greater number of successive pressings than those shewn on the drawings
when of large dimensions.
Fig. 9 shews the completed cartridge case. It will be evident how by the
gradual forcing of the metal from the base into the cylindrical part the metal will
be converted from a granular or crystalline structure into a fibrous condition, so
that by such fibrous formation any unequal straining of the several parts, and
consequently the production of weak places or cracks in the neighbourhood of the
rim will be prevented.
This method of manufacture also has the advantage that discs of any desired
thickness can be used, as whatever thickness may be taken, it will always be
reduced to the prescribed thickness for the base, the surplus metal being forced
into the rim and thence into the cylindrical part, which is also reduced by drawing
to the required thickness, the excess in length being afterwards cut off.
In determining the thickness of the disc therefore, at most the formation of the
cap chamber and the weight of the finished case have to be considered, so that the
size of the discs can be determined very accurately with a view to the economical
distribution of the metal. Of course considerably greater pressure will be required
for producing cartridge cases with thin bases from thick discs, than is necessary for
producing them from thin dises as heretofore practised.
i
Having now particularly described and ascertained the nature of my said
invention and in what manner-the same is to be performed I declare that what
1 claim is.
'
1, The herein described improved manufacture of metal cartridge cases wherein
these are formed with a base of thinner, metal than the blank from which they
. were produced.
"
2, The method of manufacturing metal cartridge cases wherein the metal is
forced by pressure in successive stages from the central part of the cup shaped
blank a Fig. 1 into the periphery d thereof and thence into the cylindrical part g
substantially as herein described with reference to Figs. 2 to 9 of the drawings.
3, The method of manufacturing cartridge cases wherein the metal blank before
its formation into cup shape has its metal forced by pressure from the centre of
the disc into the periphery thereof, so that the whole or the greater portion of the
metal for forming the cylindrical part of the cartridge is contained in the rim b¹
when this is turned up, substantially as herein described with reference to
Figs. 1° to 1b.
4, In combination with the construction of metal cartridge cases referred to in
the preceding claims, the method of forming an annular groove e in the blank for
facilitating the turning up of the rim thereon substantially as herein described
with reference to Figs. 1° to 1d of the drawings.
1
1
C
: