IMPROVEMENTS IN SUBMARINE MINES
Year: 1884

page_text: We, JOSIAH LATIMER CLARK, of 6 Westminster Chambers, Westminster, in the
County of Middlesex, Civil Engineer, and a Director of Latimer Clark Muirhead
and Company Limited of 23 Regency Street, Westminster aforesaid, and JOSEPH
PANNELL GIBBINS, of 4 Osborne Terrace, Coombe Farm Lane, Westcombe Park, in
the County of Kent, Submarine Mining and Electrical Engineer, do hereby declare
the nature of said invention for." IMPROVEMENTS IN SUBMARINE MINES" to be as
follows:
Our Invention relates in the first place to a construction of the case containing
the charge and to arrangements for inserting the charge at one operation. We
construct the outer case of two hemispheres of iron or steel, and preferably of
malleable cast iron, the two halves being bolted or otherwise equivalently fastened
together and made water-tight by means of india rubber or other suitable packing
material.
The charge is carried in a preferably square case of sheet steel or iron, into four
angle pieces in the lower hemisphere and is secured in position by means of bolts
and nuts or equivalent modes of fastening and cross-bars which reach diagonally
from corner to corner of the case and are long enough to abut against the inside of
the hemisphere. This case is intended to be kept charged with gun cotton or other
explosive and is hermetically sealed by means of a sliding lid the joint being made
secure and water-tight by suitable cement or filling material. The under portion of
the charge case is fitted with a cylinder, which projects upwards within the case,
being closed at top and open below. This open cylinder receives a similar but
smaller cylinder or envelope which fits up within it, and contains the priming
charge for the ignition of the charge.
The circuit closer is arranged so that the mine can be at pleasure changed from
an electro-contact mine, to an electro-mechanical mine or vice-versa.
When used as an Electro-contact mine a relay of peculiar construction is inserted
in the inner cylinder or envelope, the Office of which is to enable the operator on
shore to test the electrical condition of the mine-This relay consists of an Electro-
magnet and armature; the electro-magnet is wound with fine wire so as to have
a resistance of say about 2000 ohms, and the current passes through this coil and
through the detonating fuses to earth, but by reason of the resistance of the circuit
the detonators are not exploded and the armature is not attracted and the condition

page_text: of the fuses may be tested electrically, or signals may be sent through it without
danger.
The electro-magnet is also wound with a second circuit of low resistance, say
4 or 5 ohms, and a contact piece on the relay is so arranged that when a current of
greater strength is sent through the fine wire coil the armature is attracted and
completes the circuit so that the current passes not only through the fine wire coil
circuit, but is also shunted through the circuit of low resistance the result being
that the resistance of the circuit is reduced by say 2000 ohms, and the galvanometer
on shore shows the completion of this short circuit by its greatly increased deflection,
thus proving that the whole circuit is in good electrical condition and ready for
firing. If it be desired to fire the mine, a battery of excessive strength is employed
the current from which first closes the contact and at the same instant explodes the
mine.
When it is desired to employ the mine as an Electro-mechanical mine, the firing
battery is contained within the spherical case which is provided with external
contact makers for firing the mine in the usual manner, but in order to prevent
accidental discharge while laying down or taking up the mines, the circuit from the
battery to the detonating fuses is led outside the spherical-case and passes through
two lengths of submarine cable which lead away from the mine to a safe distance,
and which have their ends insulated. from each other and from the earth so that no
circuit can be formed while fixing the mine in position. As soon however as the
mine is secured, these ends are joined together and insulated so as to complete the
circuit, so that any vessel touching one of the external projecting contact pieces
will now explode the mine.
J. HENRY JOHNSON,
47, Lincoln's Inn Fields, W.C.,
Agent for the said Josiah Latimer Clark and
Joseph Pannell Gibbins,

page_text: We JOSIAH LATIMER CLARK of 6 Westminster Chambers Westminster in the
County of Middlesex Civil Engineer and a Director of Latimer Clark Muirhead
and Company Limited of 23 Regency Street Westminster aforesaid and JOSEPH
PANNELL GIBBINS of 4 Osborne Terrace Coombe Farm Lane Westcombe Park in the
County of Kent Submarine Mining and Electrical Engineer do hereby declare the
nature of said invention for "IMPROVEMENTS IN SUBMARINE MINES" and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :-
Our Invention relates in the first place to a construction of the case containing
the exploding charge and to arrangements for inserting the charge at one operation.
We construct the outer case of two hemispheres of iron or steel and preferably of
malleable cast iron the two halves being bolted or otherwise equivalently fastened
together and inade watertight by means of India rubber or other suitable packing
inaterial.
nuts c.
Figure 1 of the accompanying drawing represents the said outer spherical case
which is made of two hemispheres A B joined together by flanges ab by means of
bolts and nuts c the flanges being strengthened by ribs d between the bolts and
The upper hemisphere is provided with a sunken eye bolt a preferably
cast within the case itself for the purpose of slinging the nine, there are projecting
lugs formed on the bottom hemisphere B for the attachment chains one of these
lugs is shewn at b. An opening is left in the bottom hemisphere B for the
insertion of the envelope or casing containing the priming charge.
In the inside of the lower hemisphere are also cast formed or fixed four corner
brackets or angle pieces b³ ³ for the purpose of supporting both at bottom and at
the four corners, a square sheet iron box or shell E containing the charge of gun
cotton or other explosive-This box contains a central cylinder or chamber e (say
about 6 inches diameter and 10 inches high) which cylinder or chamber is open
at the bottom but closed at the top and is intended to receive a similar but some-
what smaller cylinder or casing F containing the circuit closer, detonators and
priming charge of the explosive.
The box E being fitted into the angle pieces or corner brackets 63 is secured in
position by means of bolts and nuts 6' b' or equivalent nodes of fastening and
by cross bars b which reach diagonally from corner to corner of the box E and are
long enough to abut against the inside of the case A. The box or case E is
intended to be kept charged with gun cotton or other explosive and tightly
closed, the joints being made secure and water tight by suitable cement or filling
inaterial.
The cylinder F containing the circuit closer detonators and priming charge is
shewn separately in vertical section in Figure 2.
The circuit closer is arranged so that the mine can be at pleasure changed from
an electro contact mine to an observation mine or vice versa.
The said circuit closer consists of a base of malleable cast iron f (for attachment
to the shell A) on which are mounted pillars G G G carrying a metal table from

page_text: which depends a helical metallic spring g and an electro-contact disc H, this disc is
insulated by a block of ebonite h from the helical spring 9. Contact springs
(preferably three) I I I are supported on the cast iron base, so near to contact with
the insulated disc H that the contact screws on the disc strike the said springs and
close the circuit whenever the mine receives a blow.
Above the relay (hereinafter described) is a wooden platform K supported on the
three pillars G G G which carries the detonators for firing the mine and the
priming charge of gun cotton or other explosive L which is kept firmly pressed
down by a disc and spiral spring at top-The whole of this apparatus is
enclosed in a drawn steel envelope F hermetically closed at top and provided with
A flange and screw collar. M and with a leather washer to make the whole air tight.
The whole apparatus is passed up into the central cylinder e Figure 1 and is
secured to the lower hemisphere B by bolts and nuts.
A relay of peculiar construction is inserted in the inner cylinder or envelope F
the office of which relay is to enable the operator on shore to test the electrical
condition of the mine-This relay which is shewn separately in elevation and plan
in figures 3 and 4 consists of an electro magnet J and armature j the core of the
electro magnet is wound with fine wire so as to have a high resistance of say for
example about 2000 ohms and also with a thick wire coil having a low resistance
say for example about four ohms. When the mine is placed in position a small
signalling current is kept constantly passing through the detonating fuses and
thence through the fine wire coil of the relay to earth, and by reason of the great
resistance of the circuit the detonators are not exploded the armature is not
attracted, and the condition of the detonators may be tested electrically or signals
may be sent through the circuit without danger. This current also passes through
an electro magnetic signalling shutter on shore but the current besides being too
feeble to fire the mine is also too feeble to drop this shutter.
This circuit of low resistance and a contact piece on the relay is so arranged that
when a testing current of greater strength is sent through the fine wire coil the
armature is attracted and completes the circuit so that the current passes not only
through the fine wire coil circuit but is also shunted through the circuit of low
resistance, the result being that the resistance of the circuit is reduced by say two
thousand ohms and the Galvanometer on shore shews the completion of this short
circuit by its greatly increased deflection, thus proving that the whole circuit is in
good electrical condition and ready for firing. If it be desired to fire the mine, a
battery of excessive strength is put in circuit the current from which first closes
the contact through the fine wire coil attracts the armature and closes the circuit
through the thick wire-coil and explodes the mine. If at any time therefore the
mine is struck by a passing vessel, the contact disc H is thrown into vibration and
momentarily touching the contact springs I it completes a short shunt circuit, by
means of the wire N between the contact springs and the earth, and this current thus
short circuited is sufficiently strong to drop the shutter on shore, and thus indicate
that the mine has been struck and the operator can then fire the mine as before
described.
The apparatus has been thus far described as an observation mine to be fired by
the signaller on shore.
But he can at will convert it into an electro contact mine to fire instantaneously
on being struck by short circuiting the firing key.
Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed I declare that what
I claim is
First-In submarine mines the construction of the outer casing of two
hemispheres within which the box containing the exploding charge is held
substantially as herein before described and illustrated in Figure 1 of the accom-
panying drawings.

page_text: Second-The employment in the contact making or circuit closing apparatus of
submarine mines, of a helical spring for suspending the contact making disc or
its equivalent substantially as hereinbefore described and illustrated by Figure 2 of
the accompanying drawings.
Third: The general arrangement and combination of parts constituting the
contact making or circuit closing apparatus of submarine mines substantially as
hereinbefore described and illustrated by figure 2 of the accompanying drawings.
Fourth For submarine mines the construction and arrangement of relay
allowing of the electrical testing of the mine and of firing by contact or observa-
tion substantially as hereinbefore described and illustrated by Figures 3 and 4 of
the accompanying Drawings.