IMPROVEMENTS IN ELECTRIC LIGHTING APPARATUS
Year: 1881

page_text: LETTERS PATENT to William Robert Lake, of the Firm of Haseltine, Lake,
& Co., Patent Agents, Southampton Buildings, London, for au Invention
of "IMPROVEMENTS IN ELECTRIC LIGHTING APPARATUS." A communication
from abroad by Warren Samuel Hill, of Boston, Massachusetts, United States
of America.
PROVISIONAL SPECIFICATION left by the said William Robert Lake at the
Office of the Commissioners of Patents on the 8th September 1881.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London. " IMPROVEMENTS IN ELECTRIC LIGHTING
APPARATUS." [A communication from abroad by Warren Samuel Hill, of Boston,
Massachusetts, United States of America.]
This Invention relates to electric lamps or lighting apparatus and comprises
various novel features hereinafter described.
According to one part of the said Invention I provide a switch which is arranged
and operated in a novel manner for changing the course of the electric current, so
that when the carbons have been burned as low as desired the switch may be made
to act mechanically to divert the current from its course through the carbons to a
nore direct passage whereby the regulating mechanism will be rendered inoperative
and the light extinguished, without thereby affecting the other lamps in the same
circuit.
I also provide a device for holding the glass globe by means of which it may be
raised and held suspended at an altitude sufficient to admit of the carbons being
replenished beneath it, thereby rendering unnecessary the removal of the globe
from the lamp.
Another part of the said Invention bas especial reference to an electric lamp, in
which two sets of carbons are provided and arranged, so that when one set of
carbons has been consumed the remaining set shall be automatically or without
manual intervention brought into use, thus admitting of a continuous light being
maintained for a longer time than could be obtained by the use of only one set
of carbons.

page_text: 1
To this end this part of my Invention consists in providing an electric lamp with
two sets of carbon holders with their accompanying feed rods, so arranged that
each feed rod receives its motion from a single set of regulating apparatus in
common, and while one set of carbons is being consumed the other set shall be
kept off the electric circuit and be otherwise entirely inoperative until such time
as the first set is burned as low as is desired, when by the operation of certain
mechanical devices, which will be hereinafter described, the circuit through the
burning carbons is broken and the second set of carbons brought together, and the
electric arc formed at their points, and the light is thus instantaneously transferred
to the new set of carbons. This result I accomplish by devices purely mechanical
in their operation or without the use of switches or other devices to change the
course of the electric current; and said mechanical devices consist of a tilting bar
or lever, pivoted at a point between the two feed rods, and so arranged that it is
held at one of its extreme points of motion by the action of a spring, and when
forced to the other extreme of its motion is caught and held by a catch or sear.
While the bar is in the latter position the points of the first set of carbons are
together and their respective feed rod is in operative connection with the regulating
apparatus, while the upper carbon of the second set is held suspended above and
out of contact with its co-operating carbon, thus the circuit is completed and the
electric arc formed at the points of the first set only. Feed rod number one is
provided with a collar placed at such a point that when the carbons are burned
nearly to their sockets the collar will strike a projecting arm of the sear, causing it
to release its hold of the tilting bar when the action of the spring causes it to
resume its normal position, and by means of a pin bearing against the under side
of the collar to raise the feed rod and upper carbon of set number one, separating
the points of the carbons of this set and breaking the electric circuit; at the same
time it releases feed rod number two and allows its suspended carbon to fall and
meet with its co-operating carbon, thus completing the circuit through the new set
of carbons and establishing the light at the meeting points of set number two
simultaneously with its extinction at the points of set number one. A continuous
light is thus maintained.
To the top plate of the lamp are secured the electro-magnets and the armature
which is connected to a support by flexible pieces which admit of its moving
perpendicularly in close proximity to the magnets. Another support furnishes
'bearing for a feed rod, which in turn carries the carbon holder and carbon. Feed
-motion-is-imparted-to-the-rod-by-means-of-a-grip,-which-is-connected_to_the
'armature by a link, and which loosely embraces the rod, allowing it to move freely
when the grip lies at a low angle, but as the end connected to the armature is
raised, placing the grip at a greater angle, the side of the opening impinges against
the rod and by its grip raises the rod, separating the points of the carbons and
producing the electric arc at said points.
L
To apply the improvements constituting the first part of my Invention to the
regulating apparatus thus described, I attach to the feed rod support a projecting
arm. To this arm is pivoted a switch bar, and it is insulated from electric
connection therewith by the use of india rubber or other non-conducting material.
A pivot or stud is made to serve as a binding post to receive a wire; to the said
arm is also pivoted a lever. The inner end of this lever extends towards and near
the feed rod while its outer end is provided with a notch which engages with a
plate acting as a sear or catch. The plate is secured to the switch bar by means of
an india rubber block whereby the plate is insulated from metallic connection with
said bar. A collar is secured to the rod by a set screw, and operates by the descent
of the rod to engage with and trip the lever. A rod is connected to the switch
bar by a screw entering an india rubber block which insulates said rod from
metallic connection with the bar. This rod extends below the plate and terminates
in a ring or eye, a spiral spring bearing against a collar on the rod acts to force the
bar against a plate of copper or other good conducting material and is secured.to
and insulated from metallic contact with the support.

page_text: The collar is placed at such a point that when the carbons have burned as low
as desired it will strike and depress the inner end of the lever, causing it to release
its hold of the plate when the action of the spring moves the switch bar, thereby
offering a more direct passage to the current which is diverted from its course, the
regulating mechanism and the carbons being thus cut out of the circuit and the
light extinguished; and inasmuch as the circuit is not broken no interruption is
caused to other lamps in the same circuit. After the lamp has been thus cut out
it may be supplied with new carbons, and again put in action by drawing down
the rod which will open the switch and restore the current to its regular course, a
notch in the lever engaging with the plate and so holding the switch "open" until
again closed by the descent of the collar.
My improved device for holding the glass globe in an electric lamp comprises &
ring adapted to embrace the bottom of the globe, having arms on either side
extending to the side rods, which rods act as guides upon which the holder is
moved up or down. The bottom of the ring is made to fit into a recess within the
plate; one of the arms is insulated from metallic connection in its bearing on a rod
by india rubber strips. The other arm is made to extend higher up on a side
rod and has two bearings thereon, the upper one consisting of a metallic band
embracing the rod and secured to the arm by screws or otherwise, while, the other
bearing is provided with a cam lever which acts by its eccentric bearing on the
rod to prevent a downward movement of the holder. The globe is raised by simply
sliding the holder upwards, the rods acting as guides or ways, and the cain lever
bearing against one rod will hold it securely at any point.
By raising the lever, thereby releasing its hold on this rod, the globe holder may
be lowered to its former position. Instead of an eccentric cam lever a simple pawl
may be used, and one or more notches made in the rod in which it may rest and
thus hold the globe holder up.
In carrying into practice the second part of my Invention I provide two feed
rod supports secured to the top plate, one at either side of the armature. At the
top of these supports is a cross piece with an arm projecting upwards, to which is
pivoted a tilting bar. A spiral spring surrounds the axis of a bar and operates to
tilt said bar. At the lower end of the armature are two studs which engage the
short ends of grip levers. These grips embrace the feed rods loosely, so that when
they lie in a horizontal position the rod moves freely through the opening therein,
but as one end of the lever is raised placing it at a slight angle, the rod is grasped
by the sides of the opening impinging against the rod, and the latter is raised and
held suspended as long as the grip is held up clear of the plate. The grip does
not fill the space between the armature and the head of the stud, but has free play
perpendicularly.
To the inner end of the grip is secured a chain by which it is connected with
the short arm of the bar. When this bar is in one position the grip is raised clear
of the plate and being suspended by the short end will, by its grip on the feed rod;
hold said rod with its carbon suspended at any point desired, and as the perpen-
dicular play of the grip on the stud is greater than the movement of the armaturo
in its ordinary working, the feed rod while in this position is unaffected by the
movement of the armature, and is thus entirely inoperative while in this position.
While the feed rod is thus suspended one grip rests on the head of the stud, and as
the armature is raised by the magnetic attraction of the magnets the grip is raised,
taking up with it the feed rod separating the carbons and producing the electric
arc at their points.
The long arm of the bar is drawn down against the tension of the spring and
is held down by a plate engaging with a hook of the sear, a spring under the arm
of the sear inaking it self-locking; as the plate passes the hook a pin projects from
the bar towards the feed rod. A collar is secured to the feed rod by a set screw,
and which may be placed so that when the carbons have burned nearly to
their holders it will bear on the arm of the sear and cause it to release its hold

page_text: of the plate, when the tension of the spring will cause the bar to change its
position.
As the long arm of the bar is raised the pin bearing against the underside of
the collar raises the rod separating the carbons, thereby breaking the circuit
between their points and extinguishing the light. A rod attached to the bar has
an offset projecting under one grip and as the long end of the bar is raised lifts the
grip to a position where, by reason of its perpendicular play on the stud, it is
unaffected by the movement of the armature and it, together with the feed rod, is
rendered inoperative.
The tilting of the bar has allowed one grip to fall until the regulating screw
resting on the top plate causes it to release its grip on the feed rod, allowing the said
rod to fall until one carbon. rests on its co-operating carbon, thereby completing the
circuit through the new carbons simultaneously with the breaking of the circuit
between the points of the nearly consumed ones, and as the feed rod is now brought
into action by the operation of the armature, the light is continuous at the meeting
points of the new set of carbons, thus avoiding the interruption which would be
necessary if only one set were employed.
While the feed rod is in operation one grip rests on the bead of the stud and is
put in operative motion by the movement of the armature, thus while either feed
rod with its respective carbons is in operation the other feed rod with its carbons
is held entirely inoperative without weight or labor to the regulating mechanism.
A pendent rod is secured to the long end of the bar and extends through and
below the top plate terminating in a.ring or eye.
When the lamp is in use the mechanism above the top. plate is covered by a
suitable case, and to put it in operation a carbon is placed in each of the upper
and lower holders, when, by drawing down the rod, the long end of the bar
is brought down and locked. One feed rod is raised enough to prevent any
current passing between the points of the carbons, and the lamp is ready for
operation, and upon receiving the proper current of electricity the other feed rod
. will be put in operation by the active movement of the armature with its
accompanying mechanism, and the light will be produced at the points of the
carbons, and will continue until said carbons are consumed nearly to their holders,
when the collar will strike the arm of the sear causing it to release its hold of the
bar and one feed rod is thrown out of operation and the other feed rod brought
into action, both changes occurring-at-the-same instant, thus transferring the light
to the new set of carbons with scarcely a perceptible interruption.
In case the lamps are employed where it is desired to maintain the light for a
continuous period through the twenty-four hours of the day, as in mines or tunnels,
the exhausted carbons may be replaced by new ones at any time after the transfer
has taken place; and by drawing down the rod and at the same time raising one
carbon the light will be re-transferred to the first set of carbons, and in this way
the second set may be held as a reserve for use while the first set is being re-
plenished and a continuous light maintained for an indefinite time. A workman
experienced in the care of electric lamps will have no difficulty in trimming the
lamp while it is in operation.
To facilitate the adjustment of the grip levers so that each lever may be made to
release its hold of the feed rod at the requisite point of elevation on the armature
I have provided adjusting screws whereby the releasing point of the grip levers
may be adjusted with perfect accuracy, and inasmuch as the adjustment may be.
made while the lamp is in operation there is no difficulty in obtaining the required
breadth of arc when either set of carbons is in operation.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said William Robert Lake in the Great Seal Patent Office on the
8th March 1882.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, and Co., Patent Agents,
Southampton Buildings, London. "IMPROVEMENTS IN ELECTRIC LIGHTING
APPARATUS." A communication from abroad by Warren Samuel Hill, of Boston,
Massachusetts, United States of America.
This Invention relates to electric lamps or lighting apparatus, and comprises
various novel features hereinafter described. According to one part of the said
Invention I provide a switch, which is arranged and operated in a novel manner
for changing the course of the electric current, so that when the carbons have been
burned as low as desired, the switch may be made to act mechanically to divert
the current from its course through the carbons to a more direct passage, whereby
the regulating mechanism will be rendered inoperative and the light extinguished,
without thereby affecting the other lamps in the same circuit. I also provide a
device for holding the glass globe, by means of which it may be raised and held
suspended at an altitude sufficient to admit of the carbons being replenished
beneath it, thereby rendering unnecessary the removal of the globe from the lamp.
Another part of the said Invention has a special reference to an electric lamp in
which two sets of carbons are provided and arranged, so that when one set of
carbons has been consumed, the remaining set shall be automatically, or without
manual intervention, brought into use, thus admitting of a continuous light being
maintained for a longer time than could be obtained by the use of only one set of
carbons. To this end this part of my said Invention consists in providing an
electric lamp with two sets of carbon holders with their accompanying feed rods,
so arranged that each feed rod receives its motion from a single set of regulating
apparatus in common; and while one set of carbons is being consumed the other
set is kept off the electric circuit and is otherwise entirely inoperative until such
time as the first set is burned as low as is desired, when by the operation of certain
mechanical devices, which will be hereinafter described, the circuit through the
burning carbons is broken, and the second set of carbons brought together and the
electric arc formed at their points, the light being thus instantaneously transferred
to the new set of carbons. This result I accomplish by devices purely mechanical
in their operation, or without the use of switches or other devices to change the
course of the electric current; and the said mechanical devices consist of a tilting
har or lever, pivoted at a point between the two feed rods, and so arranged that it
is held at one of its extreme points of motion by the action of a spring, and when
forced to the other extreme of its motion is caught and held by a catch or sear.
While the bar is in the latter position the points of the first set of carbons are
together, and their respective feed rod is in operative connection with the regulating
apparatus, while the upper carbon of the second set is held suspended above and
out of contact with its co-operating carbon, thus the circuit is completed and the
electric arc formed at the points of the first set only. Feed rod number one is
provided with a collar placed at such a point that when the carbons are burned
nearly to their sockets the collar will strike a projecting arm of the sear, causing it
to release its hold of the tilting bar when the action of the spring causes it to
resume its normal position, and by means of a pin bearing against the underside of
the collar to raise the feed rod and upper carbon of set number one, separating the
points of the carbons of this set and breaking the electric circuit; at the same time
it releases feed rod number two and allows its suspended carbon to fall and meet
with its co-operating carbon, thus completing the circuit through the new set of
carbons and establishing the light at the meeting points of set number two
simultaneously with its extinction at the points of set number one.
A continuous
light is thus maintained.
In the accompanying Drawing.
The

page_text: .embodying the first part of my Invention, with all the parts in place, and the
position of the globe and its holder when raised shewn in dotted outline.
Figure 2 is a side elevation of part of the same shewing the switch and locking
device when closed, or when the carbons have burned to their lowest limit and the
light is extinguished.
Figure 3 is an end view of a portion of the apparatus shewing the manner of
"connecting and of insulating the switch bar and the locking device.
Figure 4 is a side elevation of the parts shewn in Figure 3.
Figure 5 is an elevation of a portion of the opposite side of the apparatus.
Figure 6 is a section shewing the manner of insulating the globe bolder from
electric contact with the side rod.
Figure 7 is a section shewing the connection of the cam for holding the globe
holder when elevated by its action against the side rod.
Figure 8 represents an elevation of an electric lamp embodying the second part
of my Invention, with the electro-magnets removed and the position of the parts
upon the extinguishment of the arc between the carbons c, d, shewn in dotted
lines.
Figure 9 is a section on line x, x, Figure 8, upon an enlarged scale.
Figure 10 is a sectional plan view on line y, y.
Figure 11 is a rear view of the locking device, the position of the lever when
changed, and its relation to the feed rod and collar, being shewn in dotted lines.
My improvements may be successfully employed in combination with different
styles of regulating apparatus, I therefore do not limit myself to their use in
connection with the regulating mechanism shewn in the Drawing, which illustrates
the lamp invented by Edward Weston, with my improvements added thereto.
I will now describe the first part of my Invention as shewn in Figures 1 to 7
inclusive. In Figure 1 is shown the general form of a "Weston" lamp consisting
of the plates A, A', united at a suitable distance apart by the side rods 1, 2.
To the top plate A are secured the electro-magnets M, M, and the armature C,
which is connected to the support D by flexible pieces which admit of its moving
perpendicularly in close proximity to the magnets. The support B furnishes
bearing for the feed rod a, which in turn carries the carbon holder and carbon E.
Feed motion is imparted to the rod a by means of the grip 7, which is connected to
the armature by the link k, and which loosely embraces the rod allowing it to
move freely when the grip lies at a low angle, but as the end connected_to_the_
armature is raised, placing the grip at a greater angle, the side of the opening
impinges against the rod, and by its grip raises the rod, separating the points of
the carbons and producing the electric arc at the said points.
To apply the improvements constituting the first part of my Invention to the
regulating apparatus thus described, I attach to the feed rod support B a projecting
arm c. To this arm c is pivoted the switch bar f, and it is insulated from electric
connection therewith by the use of an india rubber or other non conducting
material. The pivot or stud e is made to serve as a binding post to receive the
wire w. To the arm c is also pivoted the lever b. The inner end of this lever
extends towards and near the feed rod a, while its outer end is provided with a
notch which engages with a plate d acting as a sear or catch. The plate dis
secured to the switch bar f by means of an india rubber block h, whereby the plate
is insulated from metallic connection with the said bar.
"
a³ represents a collar which is secured to the rod a by a set screw, and operates
by the descent of the rod a to engage with and trip the lever b; p' represents a
rod which is connected to the switch bar f by a screw entering the india rubber
block h, which insulates the said rod from metallic connection with the bar f.
This rod p¹ extends below the plate A, and terminates in a ring or eye. A spiral
spring a bearing against a collar on the rod p' acts to force the bar f against the
plate g, as shewn in Figure 2. The plate g is of copper or other good conducting
material, and is secured to and insulated from metallic contact with the support D,
as shewn in Figures 1, 2, and 5.

page_text: The operation of the parts thus specified is as follows:-
.
The lamp being put in connection with an electric generator, the current enters the
lamp at the binding post w, passing through the wire w¹ to the magnets M, M, and to
the plate A, thence down the feed rod a through the carbons E, F, producing the
light at their meeting points, up the side rod 2, and out at the binding post w",
proper insulation being employed to direct its course. The wire wins electric
connection with the binding post wand with the insulated switch bar f, which,
being held "open," as in the position shewn in Figure 1, causes no interruption to
the regular working of the lamp.
The collar a¹ is placed at such a point that when the carbons have burned as
low as desired it will strike and depress the inner end of the lever b, causing it to
release its hold of the plate d, when the action of the spring s moves the switch
bar to the position shewn in Figure 2, or into closed contact with the plate g,
thereby offering a more direct passage to the current which is diverted from its
course, the regulating mechanism and the carbons being thus cut out of the circuit
and the light extinguished; and inasmuch as the circuit is not broken no interrup-
tion is caused to other lamps in the same circuit. After the lamp has been thus
cut out it may be supplied with new carbons and again put in action by drawing
down the rod p', which will open the switch and restore the current to its regular
course, the notch in the lever b engaging with the plate d, and so holding the
switch " open "until again closed by the descent of the collar a¹, in the manner
herein before described.
My improved device for holding the glass globe in an electric lamp. comprises a
ring J adapted to embrace the bottom of the globe, having arins K, L, on either
side extending to the side rods, which rods act as guides upon which the holder is
moved up or down.. The bottom of the ring J is made to fit into a recess within
the plate A', as shewn in dotted lines. The arm K is insulated from metallic
connection in its bearing on the rod 1 by the india rubber strips z, z, shewn in
section in Figure 6. The arm L is made to extend higher up on the side- rod 2
and has two bearings P, P¹, thereon, the upper one P consisting of a metallic band-
embracing the rod and secured to the arm by screws or otherwise, while the
bearing P¹ is provided with a cam lever T which acts by its exentric bearing on
the rod to prevent a downward movement of the holder J. The bearing P¹ is
shewn in section in Figure 7. The globe is raised by simply sliding the holder.
upwards, the rods 1, 2, acting as guides or ways; and the cam lever T bearing
against the rod 2 will hold it securely at any point.
By raising the lever T, thereby releasing its hold on the rod 2, the globe holder
may be lowered to its former position. Instead of the exentric cam lever shewn,
a simple pawl may be used, and one or more notches made in the rod in which it
may rest, and thus secure the globe holder up, but I prefer the method shown.
I will now proceed to describe the second part of my Invention, shewn in
Figures 8 to 11, inclusive.. In Figure 8 is shewn the frame or body of an electric
lamp, consisting of the plates a and b united at a suitable distance apart by the
side rods A, A. To the top plate a are secured the different parts that go to make
up the automatic regulating mechanism that operates and controls the feeding'
of the upper carbons, while in the bottom plate b are secured the lower carbon
holders, as shewn at e, e. Referring to Figures 9 and 10, the electro magnets M, M,
are secured to the plate a by means of the support j. The armature with its
connecting arms is secured in like manner by the support k with the regulating
spring, dash pot, and grip shewn, all of which constitute the principal features of
the regulated mechanism of an ordinary "Weston" lamp, the operation of which
may be briefly described as follows:-The electric current entering the lamp at
one of the binding posts passes through the wire on the magnets to the frame,
thence down the feed rod through the upper and lower carbons to the opposite
binding posts, and out, proper .insulation being employed to direct its course.
its passage through the magnets their iron cores are charged with magnetisın,"
which, acting on the armature, draws it upward, lifting the feed rod and the upper
In

page_text: carbon by means of the grip which is secured to the armature grasping the feed
rod, thus separating the carbons and producing the light at their points in the
manner well understood.
In carrying into practice the second part of my Invention, I provide two feed rod
supports, which are shewn at g, gl, and are secured to the plate a, one at either
side of the armature 1. At the top of these supports is a cross piece with an arm
projecting upwards, to which is pivoted at the tilting bar m. A spiral spring 8
surrounds the axis of the bar m and operates to tilt the said bar to the position
shewn in the dotted lines. At the lower end of the armature are two studs w, w¹,
which engage the short ends of the grip levers L, L. These grips embrace the
feed rods loosely, so that when they lie in a horizontal position the rod moves
freely through the opening therein, but as one end of the lever is raised placing it
at a slight angle, the rod is grasped by the sides of the opening impinging against
the rod, and the latter is raised and held suspended as long as the grip is held up
clear of the plate a. The grip does not fill the space between the armature and the
head of the stud w, but as free play perpendicularly. To the inner end of the
grip L is secured a chain by which it is connected with the short arm of the bar m.
When the bar m is in the position shewn in Figure 8, the grip L is raised clear of
the plate a, and being suspended by the short end will, by its grip on the feed
rod h, hold the said rod with its carbon suspended at any point desired; and as the
perpendicular play of the grip on the stud w is greater than the movement of the
armature in its ordinary working, the feed rod while in this position is
unaffected by the movement of the armature, and is thus entirely inoperative
while in this position. While the feed rod h is thus suspended the grip L₁ rests on
the head of the stud w¹, and as the armature is raised by the magnetic attraction
of the magnets M, M, the grip is raised, taking up with it the feed rod h¹,
separating the carbons c, d, and producing the electric arc at their points. Thus,
while the parts are in this position the operation of the feed rod h¹ with its
co-operating parts is in all respects the same as in the ordinary lamp, having but a
single set of carbons.
The long arm of the bar m is drawn down against the tension of the spring 8,
and is held down by the plater engaging with the hook o of the sear (see
Figure 11), the spring v under the arm p of the sear making itself locking as the
plate passes the hook o; q represents a pin projecting from the bar m towards the
feed rod h'; i represents a collar secured to the feed rod h¹ by a set screw, and
-which-may-be-placed-so-that-when-the-carbons-cd-have-burned-nearly-to-their-
holders it will bear on the arm p of the sear and cause it to release its hold of the
plater,
when the tension of the spring s will cause the bar m to change its position
to that shewn in the dotted lines.
As the long arm of the bar m is raised, the pin o̟ bearing against the under side
of the collar i raises the rod h, separating the carbons c¹, d³, thereby breaking the
circuit between their points and extinguishing the light. The rod u attached to
the bar m, as shewn in Figure 10, has an offset projecting under the grip L¹, and as
the long end of the bar m is raised, lifts the grip L to the position shewn in
dotted lines, and where by reason of its perpendicular play on the stud w¹ it is
unaffected by the movement of the armature l, and it together with the feed rod h¹
is rendered inoperative.
The tilting of the bar m has allowed the grip. L to fall until the regulating
screw D resting on a plate a, causes it to release its grip on the feed rod h,
allowing the said rod to fall until its carbon c rests on its co-operating carbon d,
thereby completing the circuit through the new carbons c, d, simultaneously with
the breaking of the circuit between the points on the nearly consumed ones c¹, d₁₁
and as the feed rod h is now brought into action by the operation of the
armature the light is continuous at the meeting points of the new set of carbons,
thus avoiding the interruption which would be necessary if only one set were
employed.
While the feed rod his in operation, the grip L rests on the head of the stud w,

page_text: and is put in operative motion by the movement of the armature l. Thus, while
either feed rod with its respective carbons is in operation, the other feed rod with
its carbons is held entirely inoperative without weight or labour to the regulating
mechanism.
The pendent rod t is secured to the long end of the bar m, and extends through
and below the plate a, terminating in a ring or eye. When the lamp is in use the
mechanism above the plate a is covered by a suitable case, and to put it in
operation, a carbon is placed in each of the upper and lower holders, when by
drawing down the rod t the long end of the bar m is brought down and locked.
The feed rod h is now raised enough to prevent any current passing between the
points of the carbons c, d, and the lamp is ready for operation, and upon receiving
the proper current of electricity the feed rod h¹ will be put in operation by the
active movement of the armature 1, with its accompanying mechanism, and the
light will be produced at the points of the carbons c', d', and will continue until the
said carbons are consumed nearly to their holders, when the collar i will strike the
arm p of the sear, causing it to release its hold of the bar m, and the feed rod h' is
thrown out of operation, and the feed rod h brought into action, both changes
occuring at the same instant; thus transferring the light to the new set of carbons
with scarcely a perceptible interruption.
In case the lamps are employed where it is desired to maintain a light for a
continuous period through the twenty four hours of the day, as in mines or tunnels,
the exhausted carbons may be replaced by new ones at any time after the transfer
has taken place, and by drawing down the rod t, and at the same time raising
the carbon c, the light will be re-transferred to the first set of carbons, and in
this way the second set may be held as a reserve for use while the first set is
being replenished, and a continuous light maintained for an indefinite time.
workman experienced in the care of electric lamps will have no difficulty in
trimming the lamp while it is in operation.
A
To facilitate the adjustment of the grip levers L, L', so that each lever may be
made to release its hold on the feed rod at the requisite point of elevation on the
armature, I have provided the adjusting screws D, D, whereby the releasing
point of the grip levers may be adjusted with perfect accuracy, and inasmuch as the
adjustment may be made while the lamp is in operation, there is no difficulty in
obtaining the required breadth of arc when either set of carbons is in operation. I
am aware of the use of electric lamps wherein two sets of carbons are arranged so
that when the electric circuit has been made through both pairs, the contact
between one set of carbons is broken in advance of the other, producing the light
at the point of the pair last separated, both sets of carbons being in mechanical
operation at the same time, and the separation of the points of the idle pair being
but slightly in excess of that of the working pair. The separation of the idle
carbons thus described, is not identical with the manner of separation embodied in
my Invention, wherein the idle carbon is held motionless at a considerable distance
from its co-operating carbon.
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 under-
stood that I claim,―
First. In an electric lamp, the combination, substantially as herein before set
forth, of a switch or cut-out mechanism and a detent which holds the switch or
cut-out mechanism open and is operated by or from the feed rod to release the
said switch mechanism at the time and in the manner substantially as
specified.
Second. In an electric lamp, a switch mechanism, consisting of a stationary
plate having electric connection with one pole of the lamp, a vibratory or movable
lever or arm having electric connection with the opposite pole of the lamp, and a
spring or its equivalent which moves the lever towards the stationary plate in
combination with the feed rod, and a detent or catch adapted to hold the switch
lever out of contact with the stationary plate and operated by or from the feed rod

page_text: to release the said switch lever at the time and in the manner substantially as
hereinbefore set forth.
Third. In combination with the side rods of the lamp, the globe or shade-holding
ring having bearing arms K, L, the latter formed with two bearings P, P¹, and
provided with a cam T, substantially as and for the purposes set forth.
Fourth. In an electric lamp, the combination with the moving carbon feed rod
of a normally held opened switch or cut-out mechanism released by the action of
the said feed rod at predeterminate times, substantially as specified, and arranged
and operating when so released to automatically close and remain closed without
reference to the after movements in either direction of the feed rod, and a handle
whereby the said switch mechanism can be re-set in its open position, as herein-
before set forth.
Fifth. In an electric lamp containing two sets of carbons, the combination with
the sets of feed mechanism (one for each set of carbons) of a tilting spring or
equivalently controlled feed shifting bar connected with each set of feed mechanism
and a catch or detent which engages the said bar and is operated to release the
same at the time and in the manner substantially as specified, the whole arranged
and operating substantially as herein-before set forth.
Sixth. The combination with the independent carbon feed mechanism of the
bar holding detent operated by or from the moving feed rod of the set of carbons
in action, and the spring or equivalently controlled tilting feed-shifting bar
connected with the said feed mechanism, and formed and arranged to engage and
lift when released from the control of the detent the feed rod by which its release
was effected, substantially as herein before set forth.
Seventh. The combination of the grip levers, the carbon feed rods, the vibratory
spring or equivalently actuated feed shifting bar connected with the said grip
levers, and the detent or sear, these elements being combined and having the mode
of operation substantially as hereinbefore set forth.
Eighth. In an electric lamp, and in combination with the bar m and the collar i,
the sear having the hook o and arm 2 with the spring v, arranged and operating
to hold the said bar at one extreme of its motion, or to release the same at a point
determined by the position of the collar i on the rod h', substantially as shewn and
for the purpose specified.
Ninth. In an electric lamp, the pin q connected to the spring-actuated bar m,
and operating in combination with the collar i to raise and hold suspended the
feed rod h_while_the_feed-rod-h-is-in-operative-connection-with-the-armature,
substantially as shewn and for the purpose specified.
Tenth. The combination with the feed actuating or regulating armature and the
carbon feed rods of the grip levers and the adjusting screws carried by the same,
arranged and operating substantially as and for the purposes hereinbefore set
forth.
Eleventh. The combination, substantially as set forth, in an electric lamp, of
the vibratory spring-actuated bar or lever, the bar-holding detent, the carbon feed
rod operating to disengage the detent from the bar at the time and in the manner
substantially as specified, and the handle whereby the said bar may be moved
against the stress of its spring so as to re-engage the detent.
In witness whereof, I, the said William Robert Lake, have hereunto set my
band and seal, this Seventh of March, in the year of our Lord One
thousand eight hundred and eighty two.