IMPROVEMENTS IN GETTING COAL AND OTHER MINERALS, BLASTING OR RENDING ROCK, AND IN THE APPARATUS OR MEANS EMPLOYED THEREIN, WHICH IMPROVEMENTS ARE ALSO APPLICABLE TO OTHER PURPOSES." SIMILAR
Year: 1881

page_text: PROVISIONAL SPECIFICATION left by James Mac Nab and Richard Wade
Jenkins at the Office of the Commissioners of Patents on the 25th March
1881.
JAMES MAC NAB and RICHARD WADE JENKINS, both of Queen Victoria Street,
in the City of London. "IMPROVEMENTS IN GETTING COAL AND OTHER MINERALS,
BLASTING OR RENDING ROCK, AND IN THE APPARATUS OR MEANS EMPLOYED
THEREIN, WHICH IMPROVEMENTS ARE ALSO APPLICABLE TO OTHER
PURPOSES."
SIMILAR
Our Invention relates to improvements upon a former Invention, in respect of
which Letters Patent, dated the 9th August 1876, No. 3150, were granted to the
said James Mac Nab, the object of our improvements being to increase the
efficiency of the process and apparatus which form the subject of the said former
Invention, and to facilitate the carrying out of the said process.
One part of our present Invention has reference to the explosive cartridges or
charges employed in blasting operations, and consists of a combined or compound
explosive cartridge, or charge, which may be used either alone or in conjunction
with water or other liquid, as described in the Specification to the said former
Letters Patent.
When the compound explosive is to be used in the form of a cartridge, we
construct it in the following manner :—To a certain variable proportion of a locally-
strong, quick-burning explosive, such, for example, as dynamite, cotton powder,
(tonite) gun-cotton, nitroglycerine, "ESM" powders, Cahuc and Soulagés powder,
and the like, we add a duly proportioned quantity of a locally-weak or slow-burning
and expansive or propelling explosive, such for example as the ordinary gunpowder
used for blasting operations and artillery purposes. These respective parts are not
mixed together, but occupy positions relative one to the other.
This arrangement of a single compound-explosive cartridge we repeat indefinitely
one upon another, in order when required to increase the power of the charge,
simultaneous combustion being secured by placing a "detonator cap" in each of the
separate dynamite or quick-burning divisions of the said explosive cartridges. One
of the water cartridges described in the said former Specification may be placed
between each two successive compound explosive cartridges when practicable or
desirable. We ignite this charge by means of a train of gunpowder run down
alongside, or it may be fired by electricity, or by a wire line, safety spring
detonator, constructed substantially in the manner described in the said former

page_text: Specification. In order to secure free and simultaneous ignition of each explosive
cartridge when two or more are combined, they may be connected to each other by
short tubes, on the end of each of which is placed the detonator cap, the other end
being made to pass through the cork or other closed end into the gunpowder
division.
The improved compound explosive cartridge should invariably be placed with
the gunpowder or propelling division at the far end of the bore hole, and the same
rule of relative position should be.observed. when two or more are used together..
In lieu of employing cartridges, a compound charge may be used, substantially
such as is hereinbefore described, but without any enclosing case.
We modify the compound explosive cartridge, in order to adapt it for use in
naval and military ordnance, by placing a quick-burning local powder,.such for
example "ES M" or Cahuc and Soulagés powder in the form of a cylindrical core
running from end to end of the ordinary large grained or pebble powder charge to
insure simultaneous combustion of the whole, which we may ignite by means of
apparatus substantially such as is described in the said former Specification, or we
may employ for that purpose the powder tube or metallic squib hereinafter
described.
The compound: explosive. cartridge.or charge may be applied for all purposes
where it can be used with effect in practice for complete combustion of slow!
burning explosives.
:
We may further combine one or more of the compound-explosive cartridges in
a tube of paper, cloth, or metal, of any convenient length and required diameter,
sealed in one end thereof with the remaining part of the said tube empty, ready to
be filled up with water or other liquid immediately before use.
.
Our present Invention also has reference to further improvements in the system
of firing the charge, either in a bore-hole or in artillery, as next hereinafter
described, viz., we fill a metal tube of convenient length, diameter, and shape, with
gunpowder, and attach it to the muzzle or a muzzle holder of a detonator constructed
substantially in the manner described in the said former Specification. This powder
tube or squib may either be quite straight or be bent near its head, and screwed or
fixed into the end or side of a closed detonator muzzle at a right angle to it for
horizontal or vertical action, whichever may be most convenient. For artillery or
fire-arms this powder tube is closed at the muzzle with a conically shaped projectile
for piercing the cartridge case. To ensure ignition of the cartridge it may be fixed
in the tube muzzle with waterproof cement or with liquid-powder protected by
black varnish, and the other end "or head" is also cemented with the same
composition; or the powder for the initial flash when firing a charge in artillery, or
in the bore hole may, when convenient, be placed in the muzzle end of the detonator;
or the percussion cap action may be fixed in the head of the powder tube and
detonated by the spring striker. When the powder tube head is bent and not
screwed, but merely placed into the muzzle of the detonator, it may be kept in
position by a loop of wire twisted to it and the detonator, or otherwise. This
powder tube may also be used as a substitute for the ordinary paper powder squib,
avoiding the flash which always, accompanies the latter. This is effected by
tapering its external end to a very small diameter and inserting in it a small pellet
or pill of soft clay before charging it with powder.
When ready for firing, a needle will make a sufficient vent for ignition; and
when fired the soft clay will be at once forced to the point and confine the flash.