Year: 1888

page_text: Date of Application, 14th Mar., 1888
Complete Specification Left, 13th Dec., 1888
Complete Specification Accepted, 14th Mar., 1889

page_text: COMPLETE SPECIFICATION.
Improvements in Electric Arc Lamps.
JOHN WILLIAM KING 13 St. John's Square, Clerkenwell, London, E.C. Electro
Metallurgist 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 nature of this invention is for regulating the feed of Arc Lamps by the use
of a Solenoid with fixed core or other equivalent device together with a moveable
hammer the blows of the haminer upon the fixed part of the device causing the
descent or ascent of the tube or other equivalent device carrying the carbon holder or
holders the regulation of the speed of the blows of the hammer may be actuated by
any of the ordinary devices in use for making and breaking contact as in Electric
bells induction coils etc. With the above device may be joined a relay so that the
hammer will only come into play when the relay puts the parts in circuit.
The arrangements of the parts described may be altered in various ways to carry
out the purpose intended.
The letters of reference in the following description of Lamp refer to the illustra-
tions or drawing filed with the provisional specification as well as the drawings filed
with the complete specification.
The action of the lamp is as follows
Supposing my invention to be fixed to the top carbon rod the arc is struck by an
electro magnet moving the bottom carbon rod or by any suitable clutch on top carbon
rod in manner well known.
The Solenoid A being wound with suitable wire is placed in shunt to the main
circuit the mode of making and breaking the circuit through this solenoid may be
accomplished in various ways. In the drawings filed with complete specification I
have shown 2 ways of arrangement but there are many others or it may be entirely
separate from the carbon holders, an ordinary vibrating electric bell put in series with
the solenoid would do, the strength of the spring on the armature of the bell
being adjusted to the difference of potential at which the hammer D is required
to work.
We will suppose that the arrangement in Fig. 1 is used m & n are two springs insulated
from each other and connected in such a way that when pressed together the circuit
round the solenoid is closed and so adjusted that when they are free from the pressure
caused by the hammer D being pulled against them by the spring E they stand
slightly apart but when the bammer D is pressed against them by the spring E the

page_text: points are in contact with the projecting piece on the hammer and with each other
when in this position if the lamp is burning with the proper length of arc the shunted
current flowing through the solenoid is not of sufficient strength to move the hammer
but as the length of are increases by the carbons burning away the difference of
potential between them rises and causes more current to flow round the solenoid and
overcome the tension of the spring E-causing the hammer to be attracted by the
block C. The slight blow which the hammer gives to the block upon their touching
shifts the carbon holder & carbon and the springs m & n being released from the
pressure of the hammer D the points seperate and break the circuit the block C being
no longer magnetized releases the haminer D and the spring E again brings it in
contact with the springs m & n this again makes the circuit complete and the block (
again becomes magnetized drawing down the hammer D these repeated blows bring
the carbons nearer together untill the arc is again the proper length when the difference
of potential falls and the current going through the shunt is not sufficient to overcome
the tension of the spring E and the hammer ceases to play.
Fig. 2 is another contact arrangement in which the springs are replaced by a
rigid piece of metal O.
Fig. 3 is a relay intended to be used when the lamps are worked in parallell as then
the difference in potential between the carbons ought not to vary sufficiently to work
the hammer, but the difference in current when the arc becomes too long would cause
the relay to act and close the hammer circuit the make and break being practically the
same as when the lamps are run in series as described before any ordinary relay can
be used the one shown at Figure 3 acts as follows-
is a bobbin wound with suitable wire and placed in series with the carbons.
A A is a piece of iron with a piece of platinum on the top which makes contact
with the platinum point P when the current passing through the coil wound on the
bobbin is too weak to pull the iron core A A down against the spring Sand by
so doing completes the circuit of feeding coil together with its inake and break
attachment when the feeding action has brought the carbons again to the right distance
apart the current in the coil wound round C becomes stronger the core A A is pulled
down and the circuit of the shunt or feeding coil is broken untill the carbons have
burned away and the current in the coil wound round C again weakened, allowing the
spring S to push up the core A A against the platinum point P, and again complete
the feeding circuit.
When my invention is applied to the bottom carbon holder or rod the arrangement
of springs etc. would require to be slightly altered but the principle of action would
be the same, the bottom carbon holder and carbon ascending instead of descending
as before described.
Refering to the drawing accompanying the provisional specification
A Solenoid or bobbin wound with wire suitable for the current and E. M. F. at
which the lamp is intended to work.
B Brass tube carrying the solenoid, carbon holder, (not shown in drawing) the
fixed block C and the moveable hammer D with its suspension spring E and its nut &
screw F for regulating tension of spring.
C Fixed block.
D Moveable hammer.
E Suspension spring.

page_text: to the top carbon holder of lamp and also represents the solenoid as moving with the
carbon holder hammer etc.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed 1 declare that what I
claim is
The use of a moveable hammer and fixed block or anvil actuated by a Solenoid or
other equivalent device the whole attached to and moving with the carbon holder or
holders combined with a suitable contact breaker commutator or equivalent device
substantially as set forth.