IMPROVEMENTS IN. THE CONSTRUCTION OF ELECTRIC ARC LAMPS
Year: 1882

page_text: LETTERS PATENT to Auguste Serraillier of Gloucester Road South Kensington
in the County of Middlesex, Electrical Engineer for an Invention of
"IMPROVEMENTS IN. THE CONSTRUCTION OF ELECTRIC ARC LAMPS"
PROVISIONAL SPECIFICATION left by the said Auguste Serraillier at the
Office of the Commissioners of Patents on the 19th October 1882.
"
AUGUSTE SERRAILLIER of Gloucester Road South Kensington in the County of
Middlesex, Electrical Engineer IMPROVEMENTS IN THE CONSTRUCTION
ELECTRIC ARC LAMPS."
OF
This invention relates to a novel arrangement of apparatus for feeding the
carbons of arc lamps so as to maintain the brilliancy and steadiness of the light.
The invention applies equally to lamps in which the moving carbon moves
down to meet a fixed carbon, or in which the moving carbon rises to meet a fixed
pendent carbon, and it further applies to lamps in which both carbons are caused
to approach each other.
The upper carbon or it may be the lower, is inserted between a set of elastic
grippers made fast to the frame of the lamp and a corresponding set of elastic
grippers is carried by a horizontal plate which surrounds the carbon.
By giving this plate an up and down motion its elastic grippers will alternately
bite the carbon and force it between the fixed grippers and then slip back over
the carbon to take a fresh grip.
This rising and falling motion of the gripper plate may be obtained in various
ways. Thus a solenoid placed in a shunt or derived circuit and acting upon a
core of soft iron carried by a lever the rocking of which will pull down the
gripper plate against the upward pressure of bearing springs may be used, or the
solenoid may be placed concentric with the carbon and caused to act directly upon
the gripper plate through a hollow core fitted to that plate, the carbon in such case
passing through the core.
The descent of the upper carbon may serve to raise the lower carbon by con-
necting the holders of the two carbons together by chains or cords working over

page_text: guide and differential pulleys. When using fixed carbon holders I propose to
centre the carbons by using pairs of gripping pieces, faced up externally to a cone
shape and fitting into coned-seats.
By this means a firm grip of the carbons may be readily obtained whatever may
be the variations in the gauge of the carbons for which the holders are made.
When the carbons are both movable it will be convenient to centre the one
which is not driven by means of adjustable, spring clamps.
.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Auguste Serraillier in the Great Seal Patent Office on the
19th April 1883.
AUGUSTE SERRAILLIER of Gloucester Road South Kensington in the County of
Middlesex Electrical Engineer "IMPROVEMENTS IN THE CONSTRUCTION
ELECTRIC ARC LAMPS"
OF
This Invention relates to a novel arrangement of apparatus for feeding the
carbons of arc lamps so as to maintain the brilliancy and steadiness of the light.
The Invention applies equally to lamps in which the moving carbon descends to
meet a stationary carbon or in which the moving carbon rises to meet a stationary
pendant carbon and it further applies to lamps in which both carbons are caused to
approach each other.
In Sheet I of the accompanying drawings Fig: 1 shows in side elevation au arc
lamp constructed according to my Invention, the upper carbon being moveable and
the lower carbon stationary.
The Invention consists in the use of two sets of gripping apparatus one of which
is intended to apply to the moveable carbon the motive force for effecting the feed
of the moveable carbon and the other when that movement ceases to grip that
carbon or its holder firmly to enable the moving grippers to return to their starting
position ready to repeat the feeding action.
The frame of tlio, lamp consists of two plates A A' connected together by a pair
of vertical rods A from which rods the plate A is insulated. Made fast to this
plate A is a yoke A to which is attached a tube A* teriminating in an eye by
means of which the lamp may be suspended
This tube A is intended to receive the stem B of the upper carbon holder B
which passes through a solenoid C mounted on the plate A and through a plate D
which underlies the plate A and is fitted with a set of propelling grippers.
Fig: 2 is a section of the lamp taken at the line 1. 2 of Fig 1 and showing the
plate A of the frame inverted. This plate it will be seen is fitted with a set of
spring grippers a which are disposed radially so as to take a firm bite of the
stem B of the upper carbon holder.
Fig: 3 is a section of the lamp taken at the line 3. 4 of Fig: 1 and showing the
plate D inverted in order to represent the grippers with which it. is fitted.

page_text: Fig:
4 is a cross section of this plate showing one of the grippers in edge view as
taking its bite on the stem B¹. These grippers correspond with the grippers a of
the plate A and serve to feed the upper carbon. On the return motion however of
the plate D to take up its former position the grippers d will yield leaving the
grippers to act upon the carbon holder stem as retaining grippers. E is the
lower carbon holder which has a movement only sufficient to draw back its carbon
to produce the arc.in the well known manner by means of an electro magnet El.
The feed motion. I obtain by the action of the solenoid C which is placed within
a shunt circuit. Playing freely in this solenoid is a tubular soft iron core C' which
is pendent from a plate D' that is held up in position by a coiled spring placed
between it and the solenoid bobbin This plate is. connected by rods to the
propeller plate D the rods passing through the frame plate A which serves to guide.
the coupled plates D D in their vertical motions.
As the resistance to the main current of the lamp increases by the lengthening
of the arc, the attraction of the solenoid will increase, and drawing down its core
will cause the propelling grippers, with the plate of which the core is rigidly
connected, to draw down the upper carbon and thereby reduce the arc to the
desired length.
This will reduce the resistance of the main current to its normal state and, the
attractive force of the solenoid being proportionately reduced the coiled spring
underlying the plate D¹ will raise that plate and with it the plate D to their normal
position.
dd are adjusting screws fitted to the plate A and serving to limit the rise or
return motion of the driving plate D.
The core it will be understood is made hollow to allow the stem B¹ of the
upper carbon holder B to pass through it into the tube A¹.
a¹ a² are the binding screws for securing the wires of the main circuit to the
lamp. The course of the current through the lamp will be as follows. Supposing
it to enter at the terminal a¹ which is insulated from the frame and coupled by
a wire with the electro magnet E¹ the current will pass through the coils of this
electro magnet to the metal work of the plate A¹ of the frame and thence to
the lower carbon. From this carbon the current passes to the upper carbon
through the plate A to the insulated terminal a² and thence by a wire to the
source of supply.-The terminals of the solenoid are also connected with the
terminals a a² respectively.
An obvious modification of this Invention is shown in sectional plan and vertical
section at Figures 5 and 6.
In this modification two sets of gripping balls a & d are used in place of the
spring grippers of Figures 2 and 3 the balls being inserted in annular coned
recesses formed in bosses cast with the plates A and D respectively. These
balls are held in contact with the stem of the carbon holder by means of annular
plates surrounding the stem B₁ and borne up by coiled springs b' which are
held in place by screw caps 62 attached respectively to the bosses of the plates
A and D.
On slackening the grip of the balls by unscrewing the caps 62 the holder B will
be free to be raised to its highest position to receive a fresh carbon. The feed
of the moving or propelling plate D will be effected by an arrangement of solenoid
similar to that above described. When this feed is inverted no springs will be
needed, for the grip of the upper propelling balls will be ensured by their falling
by their own weight into the contracted portion of the annular recess, and as
respects the lower set of balls, they will, on the rising of the carbon holder, offer no
obstruction thereto. As however the propelling plate makes its return movement
the lower set of balls will like the upper spring grippers of Fig: 1 effectually retain
the carbon holder in its raised position.
The carbons I centre in the manner illustrated at Fig: 1 which shows in dotted
lines pairs of gripping pieces b³, e, faced up externally to a cone shape and fitting
into coned seats in their respective holders B and E

page_text: The externally coned pieces e will, hold fast their carbon by the simple act of
thrusting the carbon home but for the upper carbon; holder, provision is made for
retaining the cone face pieces b³ in place; for this purpose the holder is threaded
externally to receive a hollow nut b which bears on the ends of the pieces b³ and
na it is screwed.up-forces these gripping pieces into close contact with the inserted
carbon.
By means of these gripping pieces the carbons will be centred and a firm grip
may be readily obtained whatever may be the variations in the gauge of the
carbons for which the holders are made:
Fig: 7 Sheet II shows the adaptation of the Invention to an arc lamp in which
the two carbons are caused to approach each other.-The guides for the holders are
slotted to allow of studs projecting out therefrom to form a connection between
the carbon holders and propelling, chains which chains are led to a rod similar to
that shown at B₁ Fig: 1 This rod is brought under the control of, two sets of
grippers one set being actuated as above explained by means of a solenoid and
a hollow core working therein.
•
Having now set forth the nature of my Invention of "Improvements in
the construction of electric arc lamps" and explained the manner of carrying tho
same into effect I wish it to be understood that under the above in part recited
Letters Patent I claim:-
First The application to are lamps of the means above described. for actuating
automatic grippers for the purpose of feeding the carbons.
Second The application to are lamps of two sets of automatic grippers the
one set for imparting the feed motion to the moving carbon and the other set
for retaining the carbon in its advanced position as and for the purpose above set
forth.
In witness whereof I the said Auguste Serraillier have hereunto set my hand
and seal the nineteenth day of April in the year of our Lord One thousand
eight hundred and eighty three.