Improvements in the Manufacture of Cartridges.
Year: 1894

page_text: Date of Application, 17th Dec., 1894
Complete Specification Left, 30th Aug., 1895-Accepted, 17th Dec., 1895
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Cartridges.
We HAROLD BOYD of No. 16 Mangoe Lane in the City of Calcutta in the
Empire of India, Manufacturing Chemist, and WILLIAM ROBERTSON MACDONALD,
residing at No. 49 South Road, Entally in the suburbs of Calcutta aforesaid,
Gentleman, do hereby declare the nature of this invention to be as follows:-
This invention has reference to the employment of mica in the manufacture of:
cartridge cases, cartridge case linings, and wads, the objects being to exclude damp
from the explosive used in the manufacture of the cartridge, to prevent corrosion
of the barrel, and to minimise the heat generated by the explosion of the
cartridge.
Owing to the transparency of the mica, chemical and other changes set up in
the interior of the loaded cartridge can be detected, while the mica wad acts as a
lubricator along the whole length of the barrel, and the acid-proof qualities of
the mineral aid in the prevention of corrosion.
:
In carrying out this invention, the mica, which has been laminated to the suitable.
degree of thinness, is cut into pieces of a size and shape suitable for use in forming.
the cartridge case, or covering, or in lining cases constructed out of paper, card-
board, or other similar material. The base of the cartridge will, as at present,
be a metal capsule, with a central aperture for the percusion cap, but such capsule
will be covered on the inside with a mica lining, and perforated with a central
aperture, to allow the fulminate to reach the powder or other explosive. The rest
of the process of constructing the cartridge will be similar to the processes now
employed, save that the mica aforesaid will replace, or, where used as a lining, will.
be employed conjointly with, the paper, card-board, or metal, used in the
manufacture of cartridges.
The cartridge case thus formed is loaded in the usual way, but immediately
between the gunpowder or other material used as an explosive, and the bullet or
projectile to be discharged, a thick wad of mica is placed, in lieu of the wad of
felt or other material now employed for the purpose.
The mica wad (being formed out of an elastic and saponaceous substance which
does not become in any degree carbonised by the action of the heat of, or oxidised
by any acids generated in, the process of explosion) effectually cleans the barrel,
and, at the same time, lubricates it.
The heat produced by the passage of the projectile along the barrel is thus
materially diminished, while the corrosive products of the explosion are expelled,
and the barrel protected by lubrication against injury therefrom, the mica acting
as a non-conductor and insulator.
Dated this 17th day of December 1894.
:
NEWTON & SON,
Agents for the Applicants.

page_text: Improvements in the Manufacture of Cartridges.
We,
HAROLD BOYD of No. 16 Mangoe Lane, in the City of Calcutta, in the
Empire of India, Manufacturing Chemist, and WILLIAM ROBERTSON MACDONALD,
residing at No. 49 South Road, Entally, in the suburbs of Calcutta aforesaid,
Gentleman, 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 has reference to the employment of mica in the manufacture of
cartridge cases and wads, the objects being to exclude damp from the explosive
used in the manufacture of the cartridge; to prevent corrosion of the barrel; and
to minimise the action of the heat generated by the explosion of the cartridge.
The employment of mica in the formation of the wad provides a lubricator
along the whole length of the barrel; moreover, the acid-proof qualities of the
mineral deposited by friction on the inner surface of the barrel, aid in the
prevention of corrosion.
In carrying out this invention, we laminate the mica to the suitable degree of
thinness (say, to one hundredth of an inch in thickness or thereabouts), and we
then cut it into pieces of a size and shape suitable for use in the manufacture of
the cartridge case. These pieces we insert as a lining to the metal, cardboard, or
paper tubes employed in the manufacture, and the tubes thus formed we convert
into cartridges, as illustrated in the accompanying drawing, where Fig. 1 is a side
view of an improved cartridge, and Fig. 2 is a longitudinal section of the same.
a is the lined tube, made either of metal, pasteboard, or their equivalent, and to
it is applied a tubular lining of mica.
This compound tube is inserted in a flanged metal cap piece c, formed as usual
with a cap chamber for receiving the percussion cap, and it is made fast in the
metal cap piece by the inserting, under pressure, of the paper disc d, faced by a
disc of mica, which is perforated for the passage of the fire from the primer to
the powder charge e, which overlies the disc.
fis a wad of felt or other suitable material, faced on both sides with mica discs,
and upon this is set the charge of shot g, or, in lieu thereof, a bullet may be
used.
h is a disc of mica, covering the charge, and held in place by the overlapping of
the edge of the case.
By this construction of cartridge, the access of moisture to the charge will be
effectually prevented, and the corroding action of the gases evolved from the
ignited charge will be minimised.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
The use of mica in the manufacture of cartridges, as and for the purpose above
set forth.