Year: 1888

page_text: I, CHARLES AMBROSE MCEVOY of the London Ordnance Works, Bear Lane,
Southwark, in the County of Surrey, Engineer, do hereby declare the nature of this
invention to be as follows:-
In the Specification of a former Patent granted to me No. 9959 int he year 1886 I
described a firing key made in the form of a pistol with the front portion representing
the barrel capable of turning down on a hinge like the barrel of a drop-down gun.
In this firing key a safety pin was provided to lock the trigger and prevent its
being pulled unless the safety pin had heen previously withdrawn. The safety pin
when so withdrawn was allowed to hang suspended by a chain to keep it connected to
the pistol.
I now construct an electrical firing key somewhat in the same form with the forward
end capable of turning down on a hinge joint and with a trigger which when pulled
completes an electrical connection between two conducting wires but in place of
using a simple safety pin to lock the trigger which after being once withdrawn has
to be replaced by hand to again bring it into use, I now use a spring bolt pressed
endwise by a spring to cause its inner end to come in front of part of the trigger
to prevent the trigger from being moved. The other end I make to project from
the upper end of the trigger handle and form it with a small head by which it can
be drawn back. When drawn back the bolt is caught by a spring catch which retains
it in its raised position and continues to retain it until the trigger has been pulled.
When the trigger is pulled it completes a contact between two electrical conductors
as hereinafter explained and at the same time it presses back the spring catch above
mentioned and releases the bolt which is then pressed endwise by its spring on to
the upper part of the trigger and when the trigger after being pulled returns to
its normal position the bolt comes in front of it and again locks it. Thus the
safety pin always regains its position to lock the trigger after each time of the
firing key being used.
The two insulated electrical conductors which have to be coupled to complete
an electric circuit I now secure to the forward end piece or
"barrel."

page_text: I form through the "barrel" two parallel longitudinal holes into which the ends
of the two insulated conductors can be inserted. Into the inner end of each hole I
secure a metallic bush through which is a longitudinal hole large enough for the end
of the metallic conductor from which the insulating material previously surrounding
it has been removed to be passed through. The inner end of this hole is enlarged
in diameter and into it is screwed a screw plug. The metallic conductor is usually
in two or more strands these are untwisted at the end and bent outwards so that
when the screw plug is screwed into the hole it may nip them between itself and
the shoulder which is at the bottom of the enlargement of the hole through the
screw bush.
To prevent access of moisture to the two metallic bushes to which the ends of the
conductors are so secured I place at a short distance in rear of them a flexible
waterproof disc which is held around its circumference by being nipped between
the bottom of a recess in rear end of the "barrel" and a bush screwed into this
recess.
The disc at its centre carries a small disc of metal. When the barrel has been
turned into its closed position and retained by a spring catch the small metal disc
above mentioned is just in front of the end of a rod which can be pushed forward
against it by pulling the trigger. When the disc is so pushed forward it comes against
the rear ends of the two metallic bushes above mentioned and completes electrical
connection between them.
A watertight joint may also be obtained around the end portions of the insulation
upon the conductors and the holes into which they are inserted by surrounding them
with soft waterproof material which will get squeezed against the sides of the holes into
which the ends of the insulated conductors are inserted.
Dated this 24th day of February 1888.
CARPMAEL & Co.,
Agents.

page_text: Improvements in Electrical Firing Keys or Contact Makers.
I, CHARLES AMBROSE MCEVOY of the London Ordnance Works, Bear Lane, South-
wark, in the County of Surrey, Engineer, do hereby declare the nature of this
invention and in what manner the same to be performed to be particularly
described and ascertained in and by the following statement :-
In the Specification of a former Patent granted to me No. 9959 in the year 1886
I described a firing key made in the form of a pistol with the front portion representing
the barrel capable of turning down on a hinge like the barrel of a drop-down gun.
In this firing key a safety pin was provided to lock the trigger and prevent its being
pulled unless the safety pin had been previously withdrawn. The safety pin when so
withdrawn was allowed to hang suspended by a chain to keep it connected to the
pistol.
I now construct an electrical firing key somewhat in the same form with the forward
end capable of turning down on a hinge joint and with a trigger which when pulled
completes an electrical connection between two conducting wires but in place of using
a simple safety pin to lock the trigger which after being once withdrawn has to be
replaced by hand to again bring into use. I now use a spring bolt pressed end wise
by a spring to cause its inner end to come in front of part of the trigger to prevent the
trigger from being moved.
The other end I make to project from the upper end of the trigger handle and form
it with a small head by which it can be drawn back. When drawn back the bolt is
caught by a spring catch which retains it in its raised position and continues to retain
it until the trigger has been pulled. When the trigger is pulled it completes a contact
between two electrical conductors as hereinafter explained and at the same time it
presses back the spring catch above mentioned and releases the bolt which is then
pressed endwise by its spring on to the upper part of the trigger and when the trigger
after being pulled returns to its normal position the bolt comes in front of it and again
locks it. Thus the safety pin always regains its position to lock the trigger after each
time of the firing key being used.
The two insulated electrical conductors which have to be coupled to complete an
electric circuit I now secure to the forward end piece or
" barrel."
I form through the "barrel" two parallel longitudinal holes into which the ends of
the two insulated conductors can be inserted. Into the inner end of each hole I secure
a metallic bush through which is a longitudinal hole large enough for the end of the
metallic conductor from which the insulating material previously surrounding it has
been removed to be passed through. Into the inner end of this hole is screwed a screw
plug. The metallic conductor is usually in two or more strands these are untwisted at
the end and bent outwards so that when the screw plug is screwed into the hole it may
nip them between itself and the shoulder which is at the bottom of the enlargement of
the hole through the screw bush.
To prevent access of moisture to the two metallic bushes to which the ends of the
conductors are so secured I place at a short distance in rear of them a flexible water-
proof disc which is held around its circumference by being nipped between the
bottom of a recess in rear end of the "barrel" and a bush screwed into this recess.
The disc at its centre carries a small disc of metal. When the barrel has been
turned into its closed position and retained by a spring catch, the small metal disc

page_text: above mentioned is just in front of the end of a rod which can be pushed forward
against it by pulling the trigger. When the disc is so pushed forward it comes
against the rear ends of the two metallic bushes above mentioned and completes
electrical connection between them.
A watertight joint may also be obtained around the end portions of the insulation
upon the conductors and the holes into which they are inserted by surrounding them
with soft waterproof material which will get squeezed against the sides of the holes
into which the ends of the insulated conductors are inserted.
The drawing annexed shews a longitudinal section of an electrical firing key or
contact maker formed as above described.
A is a pistol handle with trigger and trigger guard. B a barrel or forward end
piece jointed to it at C. D is a spring catch for retaining the forward end and prevent.
its turning downward on the hinge joint.
The central portion of the piece B is of insulating material and through it are formed
two longitudinal holes to receive the ends of two insulated conductors E. F is a
cylindrical metallic bush closed at its front end and screwed into the rear end of each
hole through the end of each bush is a hole large enough for the metallic conducting
wire of each insulated conductor E to be passed through. G is a screw plug screwed
into each bush F by which the end of the metallic conductor can be nipped and held
against the inuer surface of the end of the bush. His a flexible waterproof disc held
in a recess at the rear end of the "barrel" B at a short distance in rear of the
metallic bushing pieces F. I is a small metallic disc carried by the centre of the
disc H and which can be pressed against both bushes F to make inetallic connection
between them. J is a rod by which the disc I can be pushed forward to bring it into
contact with the bushes F. It is carried by the handle A and is pressed backwards as
shown by a coiled spring K-but can be pressed forwards by the trigger acting against
its rear end. L is a spring bolt which locks the trigger and prevents its thrusting the
rod forwards M is a spring bolt which when the bolt L has been raised to liberate
the trigger holds it in its raised position-the bolt M is as shown formed with a
projection M which the trigger strikes against when it is pulled and presses back the
bolt M so liberating the bolt 1 and allowing it to be pressed downwards by its spring
so that when the trigger is again thrust back by the spring K it is again caught and
retained by the bolt.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performe. I declare that what 1
claim is
1. The construction of electrical firing keys or contact makers with a pistol handle
and with the front end portion capable of turning on a hinge joint and with two
insulated conductors passed through the front end portion to two metallic plates at its
rear end and with a flexible waterproof diaphragm in rear of the two plates carrying
a small metallic disc which can be pressed against the two plates and made to form
an electrical connection between thein.
2. The construction of electrical firing keys or contact makers with a spring safety
bolt for locking the trigger and a spring bolt to hold the safety bolt out of action
when it has been withdrawn and which when the trigger is pulled is itself pressed back
and made to release the safety bolt so that the safety bolt again locks the trigger
when it.returns to its backward position.
3. The construction of electrical firing keys or contact makers substantially as
herein before described and illustrated in the drawing annexed.
O
1000