IMPROVEMENTS IN ELECTRIC LAMPS
Year: 1881

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane, in the
County of Middlesex, Patent Agent, for an Invention of "IMPROVEMENTS IN
ELECTRIC LAMPS." A communication from abroad by Henry Brinsley
Sheridan, of Cleveland, in the County of Cuyahoga, State of Ohio, United
States of America.
COMPLETE SPECIFICATION filed by the said Alexander Melville Clark at
the Office of the Commissioners of Patents on the 21st October 1881.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of
A commu-
Middlesex, Patent Agent. "IMPROVEMENTS IN ELECTRIC LAMPS."
nication from abroad by Henry Brinsley Sheridan, of Cleveland, in the County of
Cuyahoga, State of Ohio, United States of America.
The object of this Invention is to prevent any change in the location or the
intensity of the light of an electric lamp.
The Invention consists in the combination with a core working in two coils having
different resistances of the mechanism hereafter described, whereby the points of
the carbons are kept in the same positions automatically; also in the combination
with the said mechanism of means whereby the cessation of a current through the
low resistance coil will cause the closing of a direct circuit through the binding
posts of the line wires; also the combination of means whereby the abnormal
separation of the carbons operates to form a short circuit between the binding
posts of the line wires, and also in the combination with the open outer ends of
the magnet coils of valve plates whereby the movement of the sliding core will be
retarded, as will be hereinafter fully described.
Figure 1 is a sectional side elevation of the lamp taken through the line x, x,
Figure 6; Figure 2 and the following Figures are drawn to a larger scale, Figure 2
being a sectional end elevation of the upper part of the lamp taken through the
line y-y, Figure 5; Figure 3 an end elevation of one of the coils; Figure 4 a
plan view of the holder for the upper carbon; Figure 5 a sectional side elevation of

page_text: the upper part of the lamp, and Figure 6 a sectional plan view of the same taken
through the line z-z, Figure 5. Similar letters of reference indicate like parts in
all the Figures:
A is a cover or case enclosing the feeding mechanism, and attached to a base
plato B.
To said base plate B is also attached the ends of an arched or U shaped bar
or frame C, to the upper parts of the arms of which are secured the two magnet
coils D, E. These coils D, E, are unequal in resistance and are placed opposite to
or in line with each other horizontally and at a little distance apart. To the
middle part of the base plate B are attached the lower ends of two standards F or
the middle part of a U shaped bar, the arms of which form two parallel standards F.
To the upper ends of the standards F is attached a stationary shaft G, upon which
revolves the cone pulley H. The cono pulley H has three parts of different
diameters 1, 2, 3. To the smallest part 1 is attached, and upon it is wound a
chain I which passes over a guide pulley J pivoted to the plate B through the
hollow arm or tube K that supports the lower carbon, around the guide pulley L
pivoted to the lower end of the said hollow. arm K, through the hollow arm M of
the globe plate N over a guide pulley O pivoted to the inner end of the said hollow
arm M down through the tube P and is attached to the pipe Q. The pipe Q is
provided at its top with a holder R¹ for the lower or negative carbon S¹ which is
secured in the said holder by a set screw or other suitable means.
To the globe
plate N is attached the lower end of the tube z which is made of such a size that
the carbon holder R¹ can move up and down within it, and is tapered at its upper
end to receive and fit upon the carbon S', and thus keep the said carbon always
vertical and in line with the carbon S. The lower end of the pipe Q is connected
with the conducting wire or cable T which passes up through the tube P through
the hollow arm M¹ of the globe plate N through the other hollow arm K', and its
end is connected with the negative binding post U. To the part 2 of the cone
pulley H, the diameter of which is twice that of part 1, is attached the end of the
chain V. This chain is wound around the part 2 of the cone pulley H in the
opposite direction to the chain I, passes over the guide pulley W pivoted to the
base plate B through a hole in the said plate B, and is attached by its other end to
the holder R for the upper or positive carbon S which is secured in the holder by
a set screw or other suitable means. The carbon holder R is made in the form of
a split tube, and the top plate of the said holder R projects at opposite sides
thereof in the form of ears, through which pass the guide rods X for the said
holder R to slide up and down upon as the chain V is wound upon and unwound
from the part 2 of the cone pulley H. The upper ends of the guide rods X are
screwed into holes in the base plate B or otherwise secured to the said plate.
The lower ends of the guide rods X are connected by a plate Y attached to them,
and which has a hole formed through it to receive and guide the carbon S, so that
the positive carbon S will always be held exactly in line with the negative
carbon S'. The holder R is connected by a conducting wire or cable Z with the
end of the low resistance coil D, and the other end of the said coil D is connected
by a conducting wire or cable a with the positive binding post U. To the wire a
is connected a branch connecting wire b, the other end of which is connected with
the end of the high resistance coil E. The other end of the coil E is connected by
a conducting wire c with the negative binding post U¹.
With this construction the bigh resistance coil E is always in the line circuit,
but the coil D is in the line circuit only when a connection is made through the
carbons S, S. To the shaft G at the side of the largest part 3 of the cone pulley H
is pivoted at its elbow a right angled lever d, the upper end of which is pinjointed
to the centre of the magnet core e, the end parts of which slide in the coils D, E.
Upon the middle part of the upright arm of the lever d, at the side opposite the
horizontal arm of the said lever is formed a horizontal arm f, to the end of which
is secured by a screw g an upright bar or plate / slotted vertically to receive the

page_text: screw g, so that the said plate can be moved up and down as may be required.
The lower end of the plate h rests upon a spring i whose inner end rests upon the
face of part 3 of the cone pulley H, which part is made a little larger in diameter
than the part 2, and has its face provided with small teeth, as shown in Figures 1
and 5. The other end of the spring i is secured to the lower part of a standard j
mounted on base plate B. The standard j is made with an offset at its middle
part and has a screw hole formed through the said offset to receive the hand
screw which passes up through the base plate B. To the upper end of the
screw is swivelled a block 7, the inner edge of which rests against the outer side
of the spring i, so that the tension of the said spring i can be regulated by turning
the said screw k. The outer edge of the block is notched to receive the upper
part of the standard j to prevent the block from turning with the screw k. To the
end of the horizontal arm of the elbow lever d is attached a pendent non-conducting
bar m which has a small copper plate n attached to its lower end. Directly
opposite and at a little distance from the copper plate n is placed a corresponding
copper plate o which is attached to the upper end of a nonconducting standard p
mounted on the base plate B. To the copper plates n, o, are attached the
conducting wires q, r, the other end of the wire q being secured to the negative
binding post U', or to the wire T leading to the said post U¹, and the other end of
the wire being secured to the positive binding post U, or to the wire a leading
to the said post U. With this construction when the bar m moves downward and
brings the copper plate n in contact with the copper plate o a direct connection
will be formed between the binding posts U, U₁, and consequently with the line
circuit.
To the horizontal arm of the elbow lever d is attached the upper end of a
spiral spring 8, the lower end of which is attached to the upper end of a screw t
which passes through the base plate B and has a milled nut u upon it to lock the
screw after adjustment to regulate the tension of the spring 8. To an arm v
attached to or formed upon the upper part of the standard T is pivoted a lever w
which has a cross slot in its forward arm to give passage to the shaft G and allow
the lever to rock upon its pivot; the end of the same arm of the lever w carrying
a pawl which engages with the teeth of the part 3 of the cone pulley H; the
other or rear arm of the lever wis connected with the horizontal arm of the elbow
lever d by a screw y passing through a slot in the lever w and screwing into one
of a series of holes in the lever d, so that the point of connection between the
levers w, d, can be adjusted at a greater or less distance from the pivot of the said
lever d as may be required.
Figure 1 shows the position of the various parts when the lamp is burning, an
electric current passing from the positive binding post U along the wire a, through
the low resistance coil D, along the wire Z, through the carbons S, S', along the
wire T to the negative binding post U¹, and on through the line circuit. At the
same time a branch or second current passes from the positive binding post U along
the wire b, through the high resistance coil E, along the wire c to the negative
binding post U', and on through the line circuit. The passage of the currents
through the carbons brings the adjacent point of the said carbons to a glow heat,
and at the same time the core e is attracted by the low resistance coil D and caused
to enter farther into it. The forward movement of the core e moves the lever d
forward and presses the plate h down upon the spring i and the spring i down
upon the part 3 of the cone pulley H, turning the said cone pulley forward or in
the direction of arrow 1. The forward movement of cone pulley H causes the
chain V on the part 2 of the said cone pulley H to be wound up, slightly raising
the positive carbon S. The same movement of the cone pulley H unwinds the
chain I from the part 1 of the said cone pulley H and lowers the negative
carbon St. By this separation of the carbons in connection with the passing
electrical current the "voltaic arc is established. The lamp will continue to burn
with the various parts in the position described until the points of the carbons S, S¹,
"

page_text: become so much separated by combustion that the electrical current through the
coil D becomes weaker than that through the coil E. When this occurs the coil E
becomes the stronger and attracts the core e, causing it to move out of the coil D
and into the coil E, thereby moving the lever d in the same direction. This
movement of the lever d raises the plate from the spring i and moves the lever w
in the same direction, the pawl x engaging with a tooth of the part 3 of the cone
pulley H and turning the said cone pulley in the direction of arrow 2, thereby
lowering the positive carbon S and raising the carbon S¹. As the levers d, w, have
different fulcra, but are being connected together, the pawl will travel faster and
farther than the holding plate h and the cone pulley H will make its movement
before being fully released from the spring i. As the current is restored to the
coil D by the approach of the carbons S, S¹, the core e is again moved forward and
the plate his again pressed down upon the spring i, thereby separating the
carbons S, S', to the proper distance to produce the arc. These various movements
occur so nearly simultaneously and continuously that there is no perceptible change
in the location or intensity of the light until the carbon holder R touches the
plate Y and the carbons are so far separated by combustion as to break the circuit
through them. The coil E now attracts the core e and moves the levers d, w, but
cannot restore the circuit through the coil D, as the carbon S cannot move any
farther downward, so that the core e will pass so far into the coil E that the
movement of the lever d will bring the copper plate n in contact with the copper
plate o and the electrical current will pass through the wires r, q, and on through
the line circuit. By this arrangement one lamp in a series can go out without in
any way affecting the burning of the other lamps in the said series.
The outer end of each of the coils D, E, is closed with a vibrating plate 4,
whereby the sliding core e is retarded by the partial compression of air in one coil
and the partial vacuum formed in the other, so that a too rapid movement of the
said core is prevented. The vibrating plates 4 also serve to keep dust out of the
interior of the coil.
Having described the nature of the said Invention, and the manner of per-
forming the saine, I declare that what I claim as new and desire to secure by
Letters Patent is,-
.
1st. In an electrical lamp, the combination with the core e working in the two
coils D, E, and the carbon holders R, R', of the lever d, provided with the arm f
and plate, the lever w provided with the pawl x having a different pivoting point
from the lever d and connected with the said lever d adjustably, the spring i, the
three part cone pulley H, and the chains I, V, substantially as herein shown and
described, whereby the points of the carbons are kept in the same position
automatically, as set forth.
2nd. In an electrical lamp, the combination with the base plate B and the
spring i, of the part j having offset, and the screw k carrying sliding block 7,
substantially as herein shown and described, whereby the tension of the said spring
can be regulated, as set forth.
3rd. In an electrical lamp, the combination with the lever d operated by the
magnet core e, and the base plate B of the nonconducting hanger m having copper
plate n, the nonconducting standard p having copper plate o, and the conducting
wires r, q, leading to the binding posts U, U₁, substantially as herein shown and
described, whereby the cessation of a current through the stronger coil will
cause the opening of a direct circuit through the said binding posts, as set
forth.
4th. In an electric lamp, the combination with the carbon holder R having
perforated guido plate, guide rods X, X, attached to plate Y and carbon S of the
carbon S¹, holder R¹, pipe Q, wire T, contact plates n, o, and wire q, r, whereby
the abnormal separation of carbons S, S', operates to form a short circuit
between the binding posts of the line wires, substantially as shown and
described.

page_text: 5th. In an electrical lamp, the combination with the open outer ends of the
magnet coils of the vibrating plates 4, substantially as herein shown and described,
whereby the sliding core is retarded, as set forth.
In witness whereof, I, the said Alexander Melville Clark, have hereunto set
my hand and seal, this Twenty first day of October, A.D. 1881.
A. M. CLARK. (L.S.)