Other Explosive.
Year: 1886

page_text: Other Explosive.
We, THOMAS JOHNSTON, General Manager, and GEORGE SMITH, Analytical
Chemist, of Nobel's Explosives Company Limited, 149, West George Street, Glasgow,
in the County of Lanark, North Britain, do hereby declare the nature of this Invention
to be as follows, that is to say:-
Our said Invention has for its object, by an improved and simple construction of
the tubes or shells forming the casings of detonators or caps, used for starting the.
explosion of charges of dynamite or other explosive, to render such starting action
more effective and satisfactory.
In carrying out our Invention we use a detonator tube which according to a practice
that has been in use for some years, is made with its inner end open, the opening being,
as usual, closed by a small disk of thinner metal than that of the tube. With this
arrangement, as is well understood, the explosive action of the fulminate or other
primary explosive with which the detonator is charged, is to some extent concentrated
so as to take effect principally from the inner end of the tube. In order to obtain a
better and more effective concentration in the axial direction of the tube we increase
the strength of the tube or of the part of it at and near the inner end by forming
corrugations in it. These corrugations may be formed along the tube by drawing the
tube through a suitably shaped die, or they may be formed round the tube by
subjecting the tube to the action of a suitably grooved milling wheel combined with
that of a small mandril forined with suitable projections and inserted into the tube.
Or the corrugations may be formed in any other convenient manner.
-The detonator tubes may be formed of the usual metal; copper or copper alloy, or of
thin steel, the steel being well annealed at the successive stages of the drawing opera-
tions by which it is reduced to the desired, size and shape. The corrugations may be
formed in the steel but need not be so deep as in copper or similar metal.
EDMUND HUNT,
Applicants' Agent.

page_text: Improvements in Detonators or Caps to be Used with Dynamite or
other Explosive.
We, THOMAS JOHNSTON, General Manager, and GEORGE SMITH, Analytical
Chemist, of Nobel's Explosives Company, Limited, 149 West George Street, Glasgow,
in the County of Lanark, North Britain, 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, that is to say -
Our said Invention has for its object. by an improved, simple, and economical
construction of the tubes or shells forming the casings of detonators or caps used for
starting the explosion of charges of dynamite or other explosive to render such starting
action more effective and satisfactory.
In carrying out our Invention we use a detonator tube, which according to a
practice that has been in use for some years, is made with its inner end open, the
opening being, as usual, closed by a small disk of thinner metal than that of the tube,
or of any other suitable material. With this arrangement, as is well understood, the
explosive action of the fulminate or other primary explosive with which the detonator
is charged, is to some extent concentrated so as to take effect principally from the inner
end of the tube or in the direction of the tube's axis. In order to obtain a better and
more effective concentration in the axial direction of the tube we increase the strength
of the tube or of the part of it at and near the inner end by, according to one modifi-
_cation, forming corrugations in it. These corrugations may be formed along the tube
or round the tube.
The detonator tubes may be formed of the usual metal; copper or copper alloy, or
they may be formed of thin steel; and when using steel we obtain the necessary
strength with thinner metal and at a reduced cost. The corrugations may be formed
in the steel but need not be so deep as in copper or similar metal; and they may be
dispensed with when the steel used is of suitable quality and thickness.
And in order that our said Invention and the manner of performing the same may
be properly understood we hereunto append a sheet of explanatory drawings to be
hereinafter referred to in more particularly describing our improvements. As deto-
nators of the kind to which our Invention relates are generally of small size the
accompanying drawings have been made to an enlarged scale, the better to show the
details; and the actual sizes of the parts are ascertainable by means of the linear scale
on the sheet of drawings; whilst the same reference letters are used to mark the same
or like parts wherever they are repeated.
Figures, 1, and 2, on the accompanying sheet of drawings are side and end elevations
of a detonator tube, T, as made with longitudinal corrugatious, and figures, 3, and 4,
are longitudinal and transverse sections showing the same tube, T, as charged with the
explosive, E, but without the end of the fuse which is fixed in the open end of the tube
in the ordinary way when the detonator is made ready for use. Figures, 5, 6, 7, 8,
are similar views of a detonator tube, T, as made with corrugations which are transverse

page_text: or extend round it, figures, 7, and 8, showing the tube as charged with explosive, E;
and figures, 9, 10, 11, 12, are similar views of a detonator tube as made of thin steel
and without corrugations.
In every case the detonator shell is first made by means of suitable dies and matrices,
in a well known way, in the form of a short tube with a closed end, and subsequently
a disk is punched out of the end so as to leave a small inwardly bent flange, A, at the
end of the tube. The opening thus made in the end of the tube is closed by the
insertion from the other end of the tube of a disk, B, of very thin metal or other
suitable material (shown by a slightly thickened line in the drawings).
The tools used for forming the longitudinal corrugations shown in figures, 1, to 4.
are shown in figures 13, to 16, figure, 13, being a section and figure, 14, a face
view of the steel matrix, through which the plain tube is forced, whilst figures, 15,
and 16, are an end elevation and a side elevation of the steel die or mandril by
means of which the tube is forced through the matrix. The hole through the matrix
is at its smallest part made with corrugations which are counterparts of those intended
to be formed on the tube.
The tools used for forming the transverse or encircling corrugations as shown in
figures, 5, to 8, are shown in figures, 17, to 20, figures, 17, and 18, being side and end
elevations of a grooved roller or milling tool, R, as attached by a screw pin, P, to a
holding arm, Q; whilst figures, 19, and 20, are end and side elevations of a mandril on
which the tube is held whilst being operated on. This mandril is formed with a
series of projections corresponding to one of the corrugations, and being fixed in the
chuck of a lathe and rotated the milling roller, R, shown in figures, 17, and 18, is
pressed against the outside of the tube. After each corrugation has been formed the
tube is shifted on the mandril so that the projections on the mandril may act on the
part where the next corrugation is to be. The mandril may be made with two or
inore series of projections so as to form two or more corrugations at once.
When steel is employed in making the detonator tubes or shells it should be of a
good mild quality capable of sustaining without injury the operations used in giving
it the desired form, and it should be well annealed, if required, after each stage of the
shaping process. And when the detonator tubes, made of steel, are to be stored or
transmitted or used where they may be liable to be affected by damp they must be
lacquered or otherwise coated so as to preserve them from rusting.
Having now particularly described and ascertained the nature of our said Invention
and in what manner the same is to be performed we declare that what we claim is :-
1-The making of detonator tubes with corrugations substantially in the manner
and for the purposes hereinbefore described.
2-The making of detonator tubes of thin steel substantially in the manner and for
the purposes hereinbefore described.
BOYUND TTTTVE