Year: 1887

page_text: Date of Application, 12th Mar.. 1887
Complete Left, 12th Dec., 1887
Complete Accepted, 3rd Feb., 1888
I JOHN LEA of 75 Arlington Road, Camden Town, Middlesex, Electrical Engineer,
do hereby declare the nature of my said invention to be as follows:-
The object of this invention is to arrange appliances in connection with the feed
from a variable resistance coil of an arc lamp, that the feed can be checked or arrested
whereby a small are may be maintained.
The invention is based upon the variable resistance appliances referred to in my
previous patent No. 1919 of the year 1882.
Now in liou of arranging the variable resistance appliances therein mentioned for
producing the feed I employ appliances in a reverse and modified form for effecting a
check upon the feed.
I dispense with gripping levers as therein described for rotating a disc that works
down the upper carbon, and I substitute a friction lever, stop or break upon the disc
or it may be some other suitable appliance for the purpose of checking the feed of the
upper carbon, or both the upper and lower carbons by means of the variable
rosistance.
I fix in a frame a train of wheels and pinions, or small and large pullies or any
other well known method of leverage whereby a very little break pressure shall retard
or check the movement.
This frame or part of its contents is actuated by an Electro-magnet or solenoid to
form the arc, and when the arc becomes longer by consumption of carbon the shunt
or derived circuit of the feed solenoid renders its core magnetic and pulls or moves it
so that it may allow the carbons to come closer together, but it does not in this lamp,
as in many others, allow the feed to run continuously, because as in my previously

page_text: mentioned invention, there is
separation and contact keeps
armature being held too long.
ог
a separation of a contact by its movement, which
checking the run down and prevents the core
The spark produced upon this separation is reduced to
a minimum which would not be the case if it were a break of the circuit instead of
variable resistance or shunt of circuit which means variable attractive force.
H. GARDNER,
166, Fleet Street, London,
Agent for the said J. Lea.
Appliances for the Purpose.
I, JOHN LEA, of 75 Arlington Road, Camden Town, in the County of Middlesex,
Electrical 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 :-
My invention relates to electric are lamps or lighting apparatus, and is chiefly
designed to provide apparatus of this kind or class which is very compact and can be
advantageously used in rooms and other places where lights of low candle-power are
required and where it has hitherto been customary to employ incandescent electric
lamps.
By my said invention I ensure great regularity in the feed of the carbon or carbons
and the maintenance of a very small arc. My said invention, therefore, provides for
a greater subdivision and more economic use of the electric current than is practicable
with the arc lamps hitherto generally used.
In the specification of former Letters Patent dated 22nd April A.D. 1882, No. 1919,
I have described an arc lamp wherein the feeding of the carbon is effected by
mechanism driven by means of a solenoid included in a shunt from the main circuit.
In this lamp there is provision for automatically increasing the resistance in the said
shunt, when required, to diminish the pull of the solenoid upon its core, the additional
resistance being obtained by the intercalation of a coil so wound that it will counteract
the attraction of the solenoid, thus avoiding any slowness of action of the parts which
might be caused by residual magnetism in the said solenoid, and ensuring regularity
in the feeding of the carbon.

page_text: conveniently and advantageously carried into practice.
Figure 1 is a front elevation."
Figure 2 a side elevation, and
Figure 3 a rear elevation of one form of my improved lamp or lighting apparatus.
Figure 4 is a plan of the said apparatus, the top plate hereinafter referred to being
removed.
Like letters indicate corresponding parts throughout the drawings.
A is the lamp-frame which comprises two plates or discs a, a' firmly connected by
rods or posts a, and having connected therewith by rods or posts a³ a socket a' for the
lower carbon B. C is the upper carbon, which is passed through holes in the top and
bottom plates a, a', and is held between rollers b, b¹. The roller bis fixed upon an
arbore carried in bearings in a frame D, which is fitted upon upright bars or posts d
so that it can move up and down thereon through a short distance. The bars or posts d
are firmly connected by a cross-bar d'. The roller 1 is carried by a lover e which
is pivoted at e to the frame D and is acted upon by a spring e² so that it prosses the
said roller against the carbon C; this carbon is thus gripped between the two
rollers with sufficient force to prevent its descending by gravitation, and to enable it
to be fed or moved downward by the rotation of the roller b. This roller is arranged
to be driven by means of suitable clockwork carried by the frame D.
E is a solenoid, which is formed of coarse wire and has a core E' which is coupled to one
arm of a lever F pivoted at F1 to a bracket or lug d² on the cross-bar d. The other
arm of this lever is coupled by means of a link F to the frame D. Therefore, when
the carbons are in contact and the required current passes through the solenoid E, the
lever F will be operated to raise the frame D and the upper carbon and thus form
the arc.
G is another solenoid which is formed of fine wire and has a core G' which is
coupled to, but insulated from a bent lever H pivoted at H' to the frame D. A pin or
stud H2 fixed in this lever is adapted to bear against the periphery of a wheel I forming
part of the clockwork.
A spring K is attached at one end to a tail-piece or extension H³ of the lever H,
and at its other end to an adjusting screw K' fitted in the frame A; this spring tends
to hold the stud H2 on the lever H against the wheel I so that the said stud acts as a
brake to arrest or retard the movement of the clockwork. The said lever also affords
the means for making and breaking or varying electrical contact for the purpose
hereinafter specified. The lever H must be insulated from the frame A; for this
purpose a piece of insulating material is placed between the said lever and its
pivot-pin H, and the spring K is connected with the screw K', and the lever H with
the core G by means of silk threads f," or other suitable insulating material.
L is a coil of wire wound in the reverse direction to the solenoid G; a core L' is
fixed within this coil thus forming an electro-magnet which, when the electric current
passes through the coil Las hereinafter described, will repel or tend to repel the
core G
M, M are the lamp-terminals which are to be connected with the two poles of a
battery or other electric generator. The terminal M is connected by a wire g with one
end of the solenoid E, the other end of which is connected by a wire h with one of the

page_text: rods or posts a³ and through this rod or post with the lower carbon B. The terminal M¹
is in electrical connection. through the frames A, D and rollers b, 6 with the upper
carbon C. The solenoid G and magnet coil L are in a shunt from the main circuit,
that is to say, one end of the solenoid is connected by a wire i with the wire g, the
other end of the said coil is connected by a wire k with one end of the coil L, and the
other end of this coil is connected with the frame A. The coil L, when the carbon is
not feeding, is short-circuited through a wire connecting the wire k with the spring K,
and, through this spring, the brake and the frames A, D), with the terminal M.
Therefore, when contact is broken by the withdrawal of the brake H2 from the wheel I,
a considerable amount of resistance will be put into the aforesaid shunt.
The operation of the improved apparatus is as follows, viz. ;--Assuming the carbons
to be so far apart that the current cannot pass through them, then, as soon as the
apparatus is connected with the generator, the current will pass through the shunt
thus energizing the solenoid G so that it draws down the lever H and thus removes tho
brake H2 from the wheel I, and extends the spring K. The clockwork being thus set
free feeds down the upper carbon C. As soon as this carbon comes in contact with
the lower carbon, the current passes through the said carbons and through the solenoid E
which, being thus energized, acts upon the lever and lifts the frame D thereby
raising the upper carbon and forming the are. As the carbons are consumed and
the resistance through the arc increases, the current will again pass through the shunt,
energizing the solenoid G, so that it draws down or tends to draw down tho lever H
and thus removes the brake from the wheel I or diminishes its pressure thereon.
When the brake is taken off, the coil L is included in the shunt thus introducing
additional resistance therein and diminishing the attraction which the solenoid G
exerts upon its core G. Moreover the current passing through the coil L magnetizes
the core in such a manner that it has a repelling effect upon the core G. The
spring K then re-acts and again applies the brake. It will be seen, therefore that the
breaking of the contact between the brake H2 and wheel I produces conditions
favorable to the re-making of the said contact. By this arrangement I avoid any
defective action of the feeding devices which might be caused by residual magnetism,
and I provide for feeding the carbon through very small distances so that a small
are will be maintained. I have moreover found in practice that the pressure of the
brake upon the wheel I is sometimes diminished to such an extent that, without
actually breaking the contact, it will permit the said wheel to rotate, the periphery of
the said wheel slipping or sliding in contact with the said brake. The resistance
through the contact is thus varied as in a microphone, with the result that part of the
current passes through the coil L as above described.
I might modify the construction of my lamp by so arranging the circuits that,
when the brake is moved out of contact with the wheel I, a portion of the shunt-
solenoid G will be short-circuited, or the direction of the current flowing through a
portion of the said solenoid reversed. I do not, however, consider such forms or
modifications of my lamp as advantageous as that hereinbefore described.
It is obvious that I can, if desired, use electro-magnets instead of the solenoids above
mentioned; and that I can employ other devices than the brake shown in the
drawings for checking or controlling the movement of the mechanism for feeding the
carbon or carbons. Moreover, the electric current need not pass through the brake or
equivalent device, if this device is connected with a suitable switch which will be
controlled simultaneously with the said device.
Having now particularly described and ascertained the nature of my said invention,
and in what manner the same is to be performed, I wish it understood that I claim :-
First. An electric are lamp wherein the feeding of the carbon or carbons is effected
by means of clockwork or other motor mechanism controlled by a brake or equivalent
device actuated by a magnet or solenoid in a shunt from the main circuit, and wherein
provision is made for switching resistance into the said shunt simultaneously with the
releasing of the said mechanism for the purpose above specified.
Second. An electric are lamp wherein the current is passed through a brake, or

page_text: equivalent device for controlling the feed-mechanism, substantially as, and for the
purpose, above specified.
Third. In a lamp of the kind or class described in the first claiming clause, the
provision of means whereby the extra resistance switched into the shunt will energizo
a magnet for counteracting the controlling magnet or solenoid, substantially as, and
for the purpose, set forth."
Fourth. The improved electric lamp consisting of the parts constructed and
combined substantially as described with reference to the accompanying drawings and
operating as above specified.
Dated this 12th day of December 1887.
JOHN LEA.
Haseltine, Lake & Co.,
45, Southampton Buildings, London,
Agents for the Applicant.