An Improved Manufacture of Cartridge-cases.
Year: 1892

page_text: Date of Application, 12th Aug., 1992-Accepted, 24th Sept., 1892
[Communicated from abroad by DIE ACTIEN GESELLSCHAFT GRUSONWERK, of
Magdeburg, Buckau, in the Empire of Germany, Manufacturers.]
An Improved Manufacture of Cartridge-cases.
1, HENRY HARRIS LAKE, of the firm of Haseltine Lake & Co.. Patent
Agents, 45 Southampton Buildings, in the County of Middlesex, 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:-
This invention relates to the manufacture of cartridge-cases, and has for its
object to simplify such manufacture chiefly with reference to the method of forming
the rim.
In the manufacture of cartridge-cases as heretofore practised special difficulties
were met with in pressing out the rim ; these difficulties are entirely overcome by
the present invention.
According to this invention the cartridge case is worked as hereinafter described
while the bottom or end of the case is vaulted or curved, and the case is then
pressed to its finished shape.
In the accompanying drawings,
Figure 1 represents in central section a form to which the lower end of the case
is first brought in any suitable or well-known manner, as for example by pressing,
drawing or casting.
Figure 2 shows an intermediate stage of the process of manufacture, and
Figure 3 shows the end of the finished case.
Figures 4, 5 and 6 are similar views illustrating a slight modification.
Referring to Figure 1 it will be seen that the bottom a is made with a con-
siderable curvature, and the angle or corner 6 between the cylindrical part and the
end is thickened for a purpose hereinafter explained.
In the outer side of the case at c is now formned either by turning, or by rolling
by means of an inclined disc of a suitable shape, an undercut annular groove some-
what of the section shown, so that the case is brought to the shape represented in
Figure 2. d is a thin rim of metal left at the end of the case after the groove c is
formed. Next, the bottom or end a is pressed flat by means of suitable stamps and
dies, whereby the rim d is caused to assume the form shown in Figure 3. The
thick or full portion b previously referred to is to provide ample strength in the
corner of the case after the end is flattened. Where it is necessary that the case
shall have a contraction e as shown in Figure 3 such contraction may be sub-
sequently produced by suitably rolling the case under a die.
If the case, after it has been finished, is to have a full annular swelling in its
interior as shown in Figure 6 instead of the groove e Figure 3 the reinforce fin
the bottom corner of the cylinder must, in the original form Figure 4, extend some
distance up the cylinder to allow of the formation of an internal annular groove g
Figure 5 in the said thickened portion. The annular ribh thus produced remains
standing when the end of the cylinder is pressed flat as shown in Figure 6.
As compared with the methods heretofore adopted, in which the metal in the
cylinder end is forced by enormous pressure to flow into the required shape for the
rim, the herein described method has the advantage that the rim can be produced
in a simple manner at a low pressure.

page_text: Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me by
my foreign correspondents, I declare that what I claim is:-
1. The herein described method of forming the rim of a cartridge-case which
consists in first producing a cylinder with a vaulted or curved end, thickened in
the corner, then providing said cylinder with an external annular groove, and
finally flattening the bottom by pressure substantially as, and for the purpose,
specified.
2. A cartridge-case such as described with reference to Figures 1 to 3 or to
Figures 4 to 6 produced in the manner substantially as described.
Dated this 12th day of August 1892.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicants.