IMPROVEMENTS IN ELECTRIC LAMPS OR LIGHTING APPARATUS Commu- nicated him
Year: 1882

page_text: LETTERS PATENT to William Robert Lake, of the firm of Haseltine, Lake,
and Co, Patent Agents, Southampton Buildings, London, for an Invention of
"IMPROVEMENTS IN ELECTRIC LAMPS OR LIGHTING APPARATUS
Commu-
nicated to him from abroad by Richard Henry Mather of Windsor,
Connecticut United States of America Electrician
PROVISIONAL SPECIFICATION left by the said William Robert Lake at.
the Office of the Commissioners of Patents on the 5th December 1882.
WILLIAM ROBERT LAKE, of the firm of Haseltine, Lake, and Co., Patent Agents,
Southampton Buildings, London, " IMPROVEMENTS IN ELECTRIC LAMPS
LIGHTING APPARATUS EA communication to him from abroad by Richard
Henry Mather of Windsor, Connecticut, United States of America, Electrician]
"
OR
This invention relates chiefly to the carbon feeding mechanism of an electric arc
lamp and comprises simple devices hereinafter described for attaining the desired
end, a perfect and reliable lamp and practically steady light. I make use of a
spring clamp which supports the upper carbon and releases it automatically as the
carbon is consumed. The clamp has, appurtenant to it, the armature of a shunt-
magnet and of a switch-magnet. I also avoid the many parts and laborious
method of fastening these parts together by means of rods and nuts as in the
ordinary form of lamp, by casting the frame of my lamp of suitable metal such as
iron in but two parts which are cheaply and easily united.
The cover or upper part of the lamp is suitably connected to the lower part of
the same which has a portion extending upwards and formning a hollow cylindrical
core of a shunt magnet and a box to contain the said shunt magnet and also a
switch magnet.
•
A spool of any insulating material such as wood is wound with a coil of
insulated fine wire the whole being arranged to fit into a box about the core and
forming the shunt magnet.
The lower carbon is held in a split tube which is inserted from below the frame
through a suitable opening and is held in place by a thumb screw or similar
device

page_text: The upper carbon is held by a rod which passes through the centre of the said
core, through an annular armature, through a spring clamp and a sleeve and
terminates at its top with a button or projecting rim. Within the said box, and
upon the insulated base of the shunt magnet is placed a switch magnet formed of a
core of soft iron wound with large copper wire. A plate of metal is placed upon
the rim of the box and is insulated from it by a washer of suitable material such
as paper.
The said plate is secured to the rim by screws which pass through insulating
washers of suitable material such as ivory or bone.
Fastened at one end to the said plate and rising above it at the other end is a
spring-clamp having in it a hole slightly larger in diameter than the rod which
passes through it. In this raised and normal position of the spring-clamp the rod
is clamped by it and held in a fixed position.
Two thin strips of metal forming brushes are fastened to the upper surface of the
said plate in such manner as to extend through openings in the said sleeve and
rest lightly against the said rod, thus ensuring good connection between the said
rod and the said plate, which plate is connected with one pole of the battery by
means of a wire leading from the pole to a post appurtenant to the said plate.
The said aunular armature is secured to the underside of the spring clamp
immediately over the shunt magnet core, and it forms also, by means of a projection,
the'armature of the switch magnet.
A post passes through the frame in contact therewith and is secured to the
wooden base of the shunt magnet.. With this post is connected a wire from the
positive pole of the battery, one terminal of the shunt magnet, and one terminal of
the switch magnet..
Another post passes through the frame and is insulated therefrom and is secured
to the base of the shunt magnet spool. Wires from the negative pole of the
battery from the other post, and the other end of the wire of the shunt magnet are
connected with this post.
I make provision for the automatic extinction of any lamp on a circuit by using
a switch magnet placed as already described and having one end of the coil
attached to the frame of the lamp and the other to 'the soft iron core of the magnet.
As soon as the upper carbon is nearly consumed the button on the aforesaid rod
strikes the top of the aforesaid loose sleeve which rests on the spring-clamp.
A switch of any ordinary form operated by hand is used on each lamp to connect
the ends of the positive and negative wires and cut the lamp to which it is affixed,
out of the circuit.
The aforesaid cover fits on a flanged rim of the aforesaid box and is secured to it
by screws. Inserted through an opening in the said cover, and held in a raised
position by a spring, is a pin or finger which when pushed down strikes the said
spring clamp, and by depressing it allows the aforesaid rod to fall and extinguish
the lamp.
By holding down the spring clamp by pressing down the pin or finger the said
rod may be slipped up through the clamp and a new carbon inserted without
removing the cover of the lamp.
I have used the term "spring clamp" as that best describes a perforated spring
in which the edges of the annular perforation bind or clamp the rod and hold it
suspended by the spring. This binding action begins at a point a short distance
below the normal position of the spring when holding the rod. It is of the utmost
importance to the perfect action of the device that these functions of spring support
and clamp be joined in one part or piece as herein described and this constitutes
one of the main features of the present invention.

page_text: Figure 4 is a plan or top view of the lamp with the cover and plate removed.
Figure 5 is a plan or top view of the box and upper plate, showing details of
construction.
Figure 6 is a vertical central section through the box and shunt magnet in a
plane at right angles to that of Figure 2.
Figure 7 is a horizontal section of the box on the line y, y, Figure 6, with part
of the lower spool-head of the shunt magnet broken away, showing the method of
connecting one terminal of the switch magnet, one terminal of the shunt magnet,
and the wire from the positive pole of the battery, with the post which passes.
through, and is in contact with, the frame of the lamp.
a denotes the cover or upper part of the lamp and 6 the lower part or frame
thereof having portions extending upward, one of which portions or extensions c
forms the hollow cylindrical core of a shunt magnet and the other portion a³ con-
stitutes a box to contain the said shunt magnet and a switch magnet. A spool of
insulating material, such as wood, is wound with a coil of insulated fine wire, the
whole being arranged to fit into the box a' about the core c, and forming the shunt
magnet d.
The lower carbon e is held in a split tube f which, is inserted from below the
frame b through a suitable aperture and is held in place by a set-screw or similar
contrivance. The upper carbon g is held by a rod h which passes through the
centre of the core c, through the annular armature i, through the spring clamp l,
and the sleeve j, and terminates at its upper part in a button or projecting rim h¹.
Within the box a¹ and upon the insulated base of the shunt magnet d is placed a
switch magnet d' formed of a core of soft iron wound with large copper wire. A
metal plate m is placed upon the rim of the box a¹ and is insulated therefrom by
a washer n of suitable material, such as paper. The plate m is secured to the rim
by screws m¹ which pass through insulating washers of ivory, bone, or other
suitable material.
The spring clamp 7 is secured at one end to the plate.m and rises above the same
at the other end; this spring clamp has an aperture slightly larger in diameter than

page_text: 2.
L
the rod h which passes through it. In the raised and normal position of the spring
clamp, the rod h is clamped thereby and held in a fixed position.
Two-thin strips p of metal, forming brushes, are secured to the upper surface of
the plate m (see Figures 3, 5 and 6) in such a manner as to extend through openings
in the sleevej (see Figures 3 and 6) and bear lightly against the rod h thus ensuring
good contact between the said rod and the plate m, which plate is connected with
one pole of the battery (in this case the negative) by means of a wire leading from
the said pole to the post o appurtenant to the said plate.
:
The annular armature i is secured to the underside of the spring clamp imme-
diately over the shunt magnet core, and forms also, by means of a projection i', the
armature of the switch magnet d¹.
A post p¹ is passed through the frame b in contact therewith and is secured to
the wooden base of the shunt magnet spool. With this post are connected the
wire (+) from the positive pole of the battery, one terminal w of the shunt magnet
and one terminal of the switch magnet, as shown in Figure 7.
A post r is also passed through the frame b (as shown in Figures 2 and 3) but is
insulated therefrom and secured to the base of the shunt magnet spool. Wires from
the negative pole of the battery, from the post o, and the other end of the wire of
the shunt maguet are connected with this post.
The operation of the improved lamp is as follows, that is to say :-A current of
electricity from any suitable source (such as a battery, or a dynamo-electric machine
in which the whole current is caused to flow through the external circuit) is passed
into the lamp at the post p¹, and, as the carbons are not in contact, through the
coil of the shunt magnet d. This current magnetizes the core c very strongly and
draws down the armature i and the appurtenant spring clamp and allows the
rod and the upper carbon to slip down by the action of gravity until the upper
carbon makes contact with the lower carbon. The main portion of the current
then passes through the carbons and only a small portion of it through the coil of
the shunt, magnet, thus releasing the armature and the spring clamp, which,
springing up, grips the rod h, lifts it, and slightly separates the carbons. The circuit
through the carbons is now the shortest path for the current, the arc is formed and
the points of the carbons become incandescent and are consumed.
In proportion as the carbons are consumed and the distance between them
increases, the strength of current through the coil of the shunt magnet is augmented
and the armature is drawn down and with it the rod h until the said rod is released
from the spring clamp and the rod and carbon fall. The rod and carbon continue
to fall until the current through the shunt magnet is decreased by the shortening
of the arc, the armature is then released and the clamp again holds the rod. If the
carbon should fall too far, that is to say, so as to strike the lower carbon, the recoil
of the spring clamp is sufficient to separate the carbons and form an arc of the
proper length.
I provide for the automatic extinction of any light in a circuit by using the
switch magnet placed as above described and having one end of the coil attached
to the frame of the lamp at the post p¹ and the other end to the soft iron core of the
magnet. When the upper carbon is nearly consumed the button h¹ strikes the top
of the loose sleeve'j which rests on the spring clamp l. The carbon now fails to
feed when the armature is depressed, and the strength of the current through the
shunt magnet increases with the length of the arc as the carbons are consumed; the
armature is, therefore; pulled down until its projecting portion ¹ comes into
contact with the core of the switch magnet. Instantly, through the coil of the
switch magnet, a new circuit is formed, magnetizing the core and retaining the
armature in its depressed position.
At the instant when the armature strikes the core of the switch magnet, there
are three circuits open for the current, one through the carbons, a second through
the shunt magnet, and a third through the switch magnet. The latter forms a
short circuit and the light goes out without extinguishing any other lamp that may
be in the same circuit..

page_text: A switch of any ordinary form operated by hand is used on each lamp to
connect the ends of the positive and negative wires and cut the lamp (to which it
is affixed) out of the circuit.
The cover a fits on the flanged rim of the box a¹ and is secured thereto by
screws. A pin 8 is inserted through an aperture in the cover a and is held in a
raised position by a spring, this pin, when pushed down, acts upon the spring
clamp and, by depressing it, allows the rod h to fall and thus extinguish the light.
By depressing the pin s and thereby holding down the spring clamp 7, the rod h
may be slipped up through the clamp and a new carbon inserted without removing
the cover of the lamp.
I have used the term "spring clamp" as that best describes the perforated
spring the edges of whose annular perforation bind or clamp the rod and hold the
same suspended. This binding action begins at a point a short distance below the
normal position of the spring when holding the rod. It is of great importance to
the perfect action of the device that these functions of spring support and clamp
should be fulfilled by one part or piece. as herein described and this constitutes one
of the main features of the present invention.
Having thus fully described the said invention as communicated to me by my
foreign Correspondent, and the manner of performing the same, I wish it understood
that I Claim, in an electric lamp or lighting apparatus:-
First. The combination of the frame, the shunt magnet, the carbon-holder or
rod h having the button ', or its equivalent, the spring support and clamp, and the
sleeve, (with or without the switch magnet) all substantially as, and for the
purposes, set forth.
Second. The shunt magnet core and the walls of the box enclosing the same cast,
or formed integrally, with the lamp-frame, substantially as, and for the purpose, set
forth.
Third. The combination of the frame 6 the shunt magnet d, the switch magnet d',
the armature i, the spring support and clamp 1, the sleevej, the rod h with the
button h¹, or its equivalent, the brushes p, the holder f and the carbons g and e, all
substantially as, and for the purposes, set forth.
Fourth. The combination of the frame b, the shunt magnet d, the armature i, the
spring support and clamp 1, the rod h, the holder f and the carbons g and e, all
substantially as, and for the purposes, set forth.
Fifth. A feeding device consisting of a carbon-supporting spring clamp operated
by a shunt magnet and by the recoil of the spring, in combination with an
automatic extinguishing device, substantially as, and for the purpose, set forth.
Sixth. The combination of the spring support and clamp secured at one end to
the lamp-frame and perforated at the other end, the rod h and the automatic
extinguishing device, substantially as described.
Seventh. The combination of a spring support and clamp secured at one end to
the lamp-frame and perforated at the other and raised end, a carbon-supporting
rod adapted to reciprocate vertically within the clamp, and a pin retracted by a
spring, all substantially as described and for the purpose specified.
Eighth. The combination of the frame b, the cover a, the pin 8 with the
supporting spring, the spring support and clamp 1 and the rod h, all substantially
as described and for the purposes specified.
In Witness whereof I the said William Robert Lake have hereunto set my
hand and seal this Fifth day of June in the year of Our Lord, one thousand
eight hundred and eighty three.
WM. ROBT. LAKE (L.S.).