A Firing Device for Internal Combustion Engines."
Year: 1897

page_text: Date of Application, 2nd Mar., 1897
Complete Specification Left, 16th Nov., 1897-Accepted, 18th Dec., 1897
PROVISIONAL SPECIFICATION.
"A Firing Device for Internal Combustion Engines."
We, ERNEST JOHN CLUBBE and ALFRED WILLIAM SOUTHEY both of 16 Elm Street,
Gray's Inn Road in the County of London, Electrical Engineers and THE ELECTRIC
MOTIVE POWER COMPANY LIMITED of 3 Salter's Hall Court, Cannon Street in the City
of London, Motor Carriage Builders, do hereby declare the nature of this invention
to be as follows:-
This invention consists of a firing device for internal combustion engines and its
object is to provide an electrical firing plug which shall be absolutely tight under
pressure, indestructible by heat and perfectly electrically insulated.
For the purpose of our invention we employ a metal plug which screws into the
engine cylinder. In this plug we fit, preferably by means of taper threads, two
sockets of an insulating material which is indestructible by heat preferably steatite.
These sockets project half an inch or more beyond each end of the plug, through the
centre of each of the sockets we pass a steel or other metal pin to conduct the current
to platinum discs which are rivetted to the inner ends of the pins. We use discs in
preference to other forms in case either of the pins should turn in its socket. The
platinum discs should be about 1/64th. of an inch apart to allow of the spark being
produced. We make the joints between the pins and the sockets by means of
asbestos and inetal washers, and we provide lock nuts at one end of the pins to hold
the whole together and form an attachment for the conducting wires.
The current is preferably supplied from an induction coil.
66
▲ Firing Device for Internal Combustion Engines."
We, ERNEST JOHN CLUBBE and ALFRED WILLIAM SOUTHEY both of 16 Elm Street,
Gray's Inn Road in the County of London, Electrical Engineers, and THE ELECTRIC
MOTIVE POWER COMPANY LIMITED of 3 Salter's Hall Court, Cannon Street in the City
of London, Motor Carriage Builders, 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:―
This invention consists of a firing device for internal combustion engines and its
object is to provide an electrical firing plug which shall be absolutely tight under
pressure, indestructible by heat and perfectly electrically insulated.
We will proceed to describe the invention with the aid of the accompanying

page_text: illustrative drawings which represent a firing device constructed in accordance
therewith:-
Figure 1 is a longitudinal section of the device and Figure 2 is a view of the inner
end of the same.
In these Figures, A is a metal (preferably brass) plug which is designed to be
screwed into the engine cylinder. In this plug A we fit, two tapered insulating
tubes B, B¹ the taper being from the inner side of the plug so that the internal
pressure tends to tighten the joint, the tube and socket being preferably threaded.
The tubes are made of an insulating material which is indestructible by heat, such
as steatite or porcelain, but we commonly use porcelain owing to the difficulty of
obtaining steatite free from metallic veins which destroy its insulating properties.
These insulating tubes B, B¹ are designed to project half an inch or more beyond
each end of the plug A, so as to allow a considérable length of insulating surface
between the contact points on the inside and outside of the plug and thereby
prevent surface leakage but in order to protect the tubes and prevent
the deposition of carbon it is preferred to continue the plug to nearly the
end of the insulating tubes as shown in Figure 1, an annular air space being left
between each tube and the plug as shown at a a. Through the centre of each of the
tubes B, B¹ we pass a loosely fitting steel or other metal pin C C to conduct the
current to the contact points which may consist of platinum discs or points rivetted
to the inner ends of the pins C C¹." We use discs in preference to other forms in
case either of the pins C should turn in its socket. The platinum discs D D¹ should
be about 1/8th. of an inch apart to allow of the spark being produced. We make a
gas tight joint between the pins and the insulating tubes by means of elastic
washers E, E preferably of asbestos and metal washers F, F¹; we find that these
elastic washers when tightened up expand inwardly and make a perfect joint between
the insulating tubes and the metal pins. We provide lock nuts G, Gi at the outer
ends of the pins C, C¹ to hold the whole together and form an attachment for the
conducting wires (not shown).
H, Hare flat disc-like heads or collars formed at or near the inner ends of the
pins C, C¹ for the purpose of taking the strain of the nuts G, G¹. These heads H, H
bear against the inner ends of the steatite tubes B B¹ through the medium of jointing
washers I, I¹ of asbestos.
The current is preferably supplied from an induction coil. In the case where the
body of the engine is in circuit it is evident that only one insulating tube and
conducting pin is required.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
Claim is :-
1. In a high-tension electrical firing plug the combination of a metal plug, tapered
tubular insulators having the requisite length of surface insulation, conducting pins
and elastic washer joints for the purpose described.
2. The electrical firing plug or firing device for internal combustion engines,
constructed substantially as hereinbefore described and shown in the accompanying
drawings.