Improvements in Electrical Firing Keys or Contact Makers.
Year: 1886

page_text: Date of Application, 3rd Aug., 1886.
Complete Left, 3rd May, 1887.
Complete Accepted, 3rd June, 1887.
PROVISIONAL SPECIFICATION.
Improvements in Electrical Firing Keys or Contact Makers.
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:-
The firing key I make in the form of a pistol and so that the contact is made by
pulling a trigger as when firing a pistol. I will also make the pistol in such a way as
to give a visible indication whenever the trigger has been pulled hard enough to
make contact.
This I effect by making the front end of the "pistol" capable of turning downwards
on a hinge joint below it and making the front end to so turn downwards when the
trigger has been pulled back with sufficient force. The joint is situated just in front
of the trigger guard. The fore end of the pistol has a metal conductor passed
longitudinally through its centre. At the front end of this conductor is a terminal to
which one of the wire conductors of an electric circuit may be coupled and at the back
end of the conductor is a metallic plate against which a metallic pin carried by the
handle end of the pistol is to be brought to complete a contact-preferably this
metallic plate is made capable of yielding somewhat when pressed against by the
metallic pin but is pressed back by a spring to its normal position when the pin is not
forced against it.
When the trigger is pulled it acts against the rear end of the metallic pin and forces
it forwards to bring its forward end into contact with the above mentioned metallic
plate. At other times the metallic pin is pressed back by a coiled spring around it.
When the barrel end is turned up to bring it into firing position it is caught and
retained by a spring catch at the top-at the same time it forces back a small spring

page_text: bolt which when the catch is released acts to press the barrel end downwards. When
the metallic pin is pressed forward by the trigger a projection upon it acts against an
incline on the catch and releases it just as it makes a contact or in other ways it is
caused to release the catch at this time.
The metallic pin is by a wire always in electrical connection with a terminal at the
end of the handle and to this terminal the second conducting wire of the electric
circuit is coupled.
Firing keys constructed as above described are applicable more especially for
firing ordnance by electricity or for firing mines or torpedoes or for such like
purposes.
Dated this 3rd day of August 1886.
CARPMAEL & Co.,
Agents for the Applicant.

page_text: Improvements in Electrical Firing Keys or Contact Makers.
I, CHARLES AMBROSE M°EVOY of The London Ordnance Works, Boar Lane,
Southwark in the County of Surrey Engineer 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 :-
The firing key I make in the form of a pistol and so that the contact is made by pulling
a trigger as when firing a pistol. I also make the pistol in such a way as to
give a visible indication whenever the trigger has been pulled hard enough to make
contact.
"
This I effect by making the front end of the "pistol" capable of turning downwards
on a hinge joint below it and making the front end to so turn downwards when the
trigger has been pulled back with sufficient force. The joint is situated just in front
of the trigger guard. The fore end of the pistol has a metal conductor passed
longitudinally through its centre. At the front end of this conductor is a terminal to
which one of the wire conductors of an electric circuit may be coupled and at the
back end of the conductor is a metallic plate against which a metallic pin carried by
the handle end of the pistol is to be brought to complete a contact preferably this
metallic plate is made capable of yielding somewhat when pressed against by the
metallic pin but is pressed back by a spring to its normal position when the pin is not
forced against it.
When the trigger is pulled it acts against the rear end of the metallic pin and forces
it forwards to bring its forward end into contact with the above mentioned metallic
plate. At other times the metallic pin is pressed back by a coiled spring around it.-
When the barrel end is turned up to bring it into firing position it is caught and
retained by a spring catch at the top-at the same time it forces back a small spring
bolt which when the catch is released acts to press the barrel end downwards. When
the metallic pin is pressed forward by the trigger a projection upon it acts against
an incline on the catch and releases it just as it makes a contact or in other ways it is
caused to release the catch at this time.
The metallic pin is by a wire always in electrical connection with a terminal at the
end of the handle and to this terminal the second conducting wire of the electric
circuit is coupled.
Firing keys constructed as above described are applicable more especially for
firing ordnance by electricity or for firing mines or torpedoes or for such like
purposes.
The drawing shows a longitudinal section of a contact maker formed as above
described.
A is the hinge joint upon which the front portion B is free to turn downwards-C is
the pistol handle forming the rear portion. D is a metallic conductor carried lengthwise
through the front portion B. At its front end it is coupled to a terminal or
terminals E to which the wire conductors of electric firing circuits may be coupled-

page_text: two terminals are shown to be provided so that the contact maker may be used for
simultaneously completing two circuits. At its rear end the conductor D is coupled
to a metallic plate F.
G is a metallic pin carried by the part C it is pressed backwards away from the
plate F by a coiled spring as shown. H is the trigger which when. pulled thrusts
the pin G forwards. I is a lever through which the front end of the pin G passes.
When the pin G is thrust forwards it rocks this lever and lifts the spring catch J by
which the front part B is held and so allows this part to then drop down. The turning
down of the part B is assisted by a spring K which thrusts a rod K¹ against the
plate F.
The pin G with the spring which surrounds it are as shown contained within a
metallic casing and this by a wire Li is in electrical connection with a terminal M at
the end of the handle. N is a safety pin which can be passed through the trigger to
lock it until just before firing..
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:-
The construction of electrical firing keys or contact makers in the form of a pistol
and with the front end made to turn downwards when the trigger has been pulled and
the contact made substantially as described.