IMPROVEMENTS IN THE MANUFACTURE OF CARTRIDGES
Year: 1884

page_text: COMPLETE SPECIFICATION.
I, WILLIAM PHILLIPS THOMPSON, Fel. Inst. P. A., of the Agency for Foreign
Patent Solicitors, 6 Lord Street, Liverpool, in the County of Lancaster, and
323 High Holborn, in the County of Middlesex, Civil Engineer do hereby declare
the nature of the said invention for "IMPROVEMENTS IN THE MANUFACTURE OF
CARTRIDGES," and in what manner the same is to be performed, to be.particularly
described and ascertained in and by the following statement:-
In cartridges of the usual construction, whether made entirely of metal or of
paper, or of one or more materials combined, the powder is liable to be deteriorated
more or less rapidly by the combined influence of heat and of moisture. This
action commences soonest in paper cartridges, metallic cartridges resist somewhat
longer, but as soon as deterioration commences it progresses very fast and the
cartridges are soon spoilt.
To avoid these drawbacks it is necessary to make use in the manufacture of the
cartridges of a material absolutely impermeable to moisture, not acted upon by the
constituents of the powder, and sufficiently strong not to be torn or broken by the
deflagration thereof. For this purpose, a special paper is manufactured composed of
pure cellulose, derived either from new linen rags or from hemp or flax. This paper
made without size and without addition of any foreign matters is passed through
a bath of sulphuric acid, afterwards it is washed with a sufficiency of water, and
pressed, until the acid is completely removed. It is then thoroughly dried and
calendered. The paper is then cut into sheets of the requisite size, and these are
passed through a surfacing machine under heavy pressure. This process yields a
paper comparatively thin but extremely dense, and impervious though transparent.
From this paper the cartridges are manufactured, each sheet is cut into pieces of
the requisite size, and covered with a suitable adhesive material; it is then rolled
up in cylindrical form to treble thickness. This cylinder is dried, calibrated and
smoothed in the usual manner. After having been cut to length, the cylinders
pass into a machine which crimps or folds up one end, leaving space in the centre
for the cap. This arrangement prevents the base from bursting away from the
cartridge shell when the powder is fired. The cartridge is completed in the
ordinary manner, the base, cap, anvil etcetera being constructed and attached as
Price 2d l

page_text: usual: the cap however containing the fulminate may have this substance covered
by a disc of the prepared paper instead of by the disc of metal usually employed.
For this purpose the paper is made inuch thinner than for the cartridge shell.
This improvement has, besides the advantage of more efficiently protecting the
fulminate, that of rendering the contents of the cap visible, the paper being
transparent, so that if the fulminate be displaced, or wanting, the deficiency
becomes visible; moreover the paper being burnt by the explosion of the cap,
permits free access of the flame to the interior of the cartridge, causing a quicker
combustion of the powder, the rapidity of combustion of the powder may be further
enhanced by making little holes in the paper disc.
The wads may be made of the same prepared paper but thicker.
Cartridges made according to this method are absolutely impermeable and
unalterable, whatever be the temperature and dampness of the air surrounding
them, which has therefore no action upon the powder enclosed in them. To make
coloured shells the paper may be passed through a dye bath at the end of the
washing process above described.
Having now particularly described and ascertained the nature of the said
invention as communicated to me, and in what mannor the same is to be performed,
I declare that what I claim is:-
1. The manufacture of cartridge shells from paper of pure cellulose treated with
sulphuric acid, washed, calendered, pressed, and surfaced, substantially as described.
2. The manufacture of cartridge shells of the above described material, crimped
or folded over at one ond to prevent the base from leaving the shell.
**
3. In cartridges manufactured in the manner above described, the use of a disc
of paper prepared in the manner above described to cover the fulminate contained
in the cap.
"4 In cartridges of the above described construction, the use of wads of
parchment paper all substantially as and for the purposes herein described.
Dated this 23rd day of September 1884.