IMPROVEMENTS IN CENTRAL-FIRE CARTRIDGES FOR BREECH-LOADING FIRE-ARMS AND ORDNANCE
Year: 1868

page_text: PROVISIONAL SPECIFICATION left by John Abraham at the Office
of the Commissioners of Patents, with his Petition, on the 5th
December 1868.
I, JOHN ABRAHAM, of Birmingham, in the County of Warwick,
Machinist, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN CENTRAL-FIRE CARTRIDGES FOR BREECH-LOADING FIRE-ARMS
AND ORDNANCE," to be as follows:-
My Invention consists, firstly, in constructing and arranging the parts
of central-fire cartridges for breech-loading fire-arms and ordnance in the
manner herein-after described. I make the chamber to receive the anvil
and percussion cap of a cylindrical figure and in one piece with the head
of the cartridge case, the sides of the said chamber being made of a
double fold of the metal of the said head. A hole of a size
proper
admit the percussion cap to be used is made in the centre of the said
head. The anvil, herein-after described, is introduced into the chamber
from the open end or mouth of the cartridge case, and the said chamber
is closed upon and made to retain the said anvil. The said chamber is
to

page_text: made by pressing or shaping, by dies and pressure, a deep annular groove
or depression in tho flat part of the head; a portion of the metal of
the head is thereby forced into the interior of the powder case, the
double fold described of the chamber being at the same time produced.
The anvil herein-before referred to consists of a conical block of metal
having in its axis a hole or passage, and in its base, and concentric
with its axis, a deep groove or depression of a size proper to receive an
ordinary percussion cap. The annular groove or depression and central
hole form a nipple somewhat similar to the nipple of an ordinary gun
or pistol. After the anvil has been introduced into the cylindrical
chamber (its base or largest end being turned towards the opening in
the head of the cartridge case) the said chamber is by means of dies
and pressure closed upon the said anvil, that is, the chamber is by the
closing process changed from a cylindrical to a conical figure and made
to fit closely-upon the-conical-anvil; the said anvil-is-thereby firmly
fixed in the said chamber, and by placing a percussion cap on the nipple
of the anvil the discharging parts of the cartridge are complete. The
cartridge is discharged by striking the percussion cap on the nipple, the
flash or fire from the said cap passing down the central hole of the
nipple to the gunpowder of the cartridge. Although I prefer to make
the cartridges wholly of metal, yet the head only may be made of metal,
the other part being made of paper or other non-metallic material, and
although I prefer to introduce and fix the anvil in the chamber in the
manner before described, yet I do not limit myself thereto, as the anvil
may he introduced into the said chamber through the head of the
cartridge case. Instead of introducing an anvil into the said chamber,
on which said anvil a percussion cap is placed, the anvil and percussion
cap may be dispensed with, and the fulminate or detonating powder may
be placed directly in the said chamber. In this case I close the cylin-
drical chamber somewhat flatter, and make the opening in the centre
of the head somewhat smaller than when an anvil and cap are to be
introduced into the said chamber.
My Invention consists, secondly, in preventing the rupture or bursting
of the metallic heads of cartridges by making on the cylindrical part
of the cartridge case and near the flange or rim thereof one or more
annular grooves or depressions, that is, I press the metal of the case
inwards so as to form inside the case an annular rib or projection of

page_text: ribs or projections. On the discharge of the cartridge the force of the
explosion acts upon the annular ribs or projections and flattens them,
and theroby causes a longitudinal expansion of the cartridge case, and
relieves the head of the said cartridge case from the strain to which it
is ordinarily subjected.