Improvements in Electric Arc Lamps.
Year: 1897

page_text: Date of Application, 23rd Sept., 1897-Accepted, 8th Jan., 1898
COMPLETE SPECIFICATION.
Improvements in Electric Arc Lamps.
I, THOMAS EDGAR ADAMS, of 938 Case Avenue, Cleveland, in the County of
Cuyahoga and State of Ohio, United States of America, Electrician, do hereby declare
he 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:-
This invention relates to an improvement in Electric Arc Lamps, one object of the
nvention being to provide an accurate and durable electro-magnet regulating
mechanism whereby to move both carbons for separating them and establishing the
are and regulating its length and brilliancy.
A further object is to provide an electro magnet having one or more circuits so
disposed and arranged upon a single core having three pole pieces, that the latter
will act upon an iron bar, as an armature, and form consequent and salient poles, said
armature being mounted so as to move freely and in such manner that the magnetic
lines will pass from the central pole of the magnet to said armature and tend to
retain the latter in proper position.
A further object is to so mount an air pot and connect it with the armature of the
magnet, as to reduce friction on the piston and its rod, to a minimum.
A further object is to provide a self contained electro-magnet i.e., one having its
armature supported upon itself, such support comprising hardened knife edges and
the magnetism assisting in such support and permitting movement of the arinature
with minimum friction and with freedom from clogging with dirt.
A further object is to provide means for automatically switching a faulty lamp out
of circuit.
A further object is to provide an improved clutch for an electric arc lamp.
A further object is to provide improved means for supporting the globe.
A further object is to provide an improved guide for the lower carbon.
A further object is to guard against the entrance of rain, snow or insects into the
globe to a troublesome degree.
A further object is to provide means at the top of the globe to prevent the same
from breaking and also aid in supporting the globe net.
A further object is to so construct an electric arc lamp that heat and cold will not
practically change the length of the arc.
With these objects in view the invention consists in an electro-magnet constructed
with two salient poles of one and the same polarity and an intermediate or con-
sequent pole of polarity different from that of the salient poles, and an armature
pivotally supported by the intermediate or consequent pole and adapted to be turned
on its fulcrum by the salient poles.
The invention further consists in the combination with a magnet having salient
poles of like polarity and a consequent pole of the other polarity, of an armature
pivotally supported between its ends by the consequent pole within the path of the
lines of force, said armature being constructed and adapted to be vibrated by the
action of the salient poles.
The invention further consists in an electro-magnet having salient poles of like
volarity and consequent pole of the other polarity, of a pole shoe on the consequent
:

page_text: pole, an armature having knife edge bearings between its ends on said pole shoe,
said armature being adapted to be vibrated by the action of the salient poles of
the magnet.
.
The invention further consists in the combination with a magnet, of an armature
made in separate sections and a yielding thermostatic strip secured to and connecting
said sections.
The invention further consists in certain novel features of construction and
combinations and arrangements of parts as hereinafter 'set forth and pointed out in
the claims.
In the accompanying drawings, Figure 1 is a front elevation of my improved lamp
with the casing in section Figure 2 is a rear elevation showing the operating
mechanism. Figures 3, 4, 5, 6, 7 and 8 are views illustrating various details. Fig. 9
is a diagrammatical view.
A represents the casing for the operating mechanism of the lamp, which casing is
preferably made of cast metal and comprises a top a; a floor or bottom 6 and
upright walls c, made in sections and secured to the top a and bottom b, some of said
sections being hinged to form doors whereby to permit ready access to the interior
of the casing.
A magnet is disposed within the casing and supported from the top a. This
magnet comprises a core 1 and two coils 2, 3, spaced apart on said core and so wound
as to form a magnet having salient poles 4, 5 and a consequent pole 6; the salient
pole pieces being made to project laterally at right angles from the core. In other
words the magnet is constructed to have ends of one and the same polarity and an
intermediate portion of a polarity opposite from the ends. The coil 2 is of coarse
wire and included in series with the electrodes, while the coil 3 is of fine wire and
included in a shunt circuit around the electrodes. To the consequent pole of the
magnet, a shoe or pole piece 7 is secured by means of arms 8, and made with an
outer curved face. The arms 8 project outwardly beyond the curved face of the shoe
or pole piece 7 and between them an armature B is disposed and provided at points
centrally or nearly so, between its ends with recesses for the accommodation of said
arins 8, the respective ends 9, 10, of said armature being somewhat enlarged and
beveled so as to be attracted by the respective salient poles 4, 5, of the magnet.
plate or strip 11 (preferably of steel), is secured to the inner face of the armature B
nearly centrally between the ends of the latter, and to the lower portion of the curved
face of the shoe or consequent pole piece 7, a steel plate 12 is secured, said plate
being beveled so as to form a knife edge 13, upon which the lower edge of the
plate 11 has its bearing. Another steel plate or strip 14 is secured to the inner face
of the armature and made with a knife edge 15 which bears against the under edges
of the arms 8, in close proximity to the knife edge of plate 12, and said arms 8 may,
if desired, be made of steel.
A
To prevent accidental outward displacement of the armature, stops 16 are secured
to the arms 8 and depend behind the ends of the steel plate or strip 14. From this
construction and arrangement of parts it will be seen that the armature will be
delicately mounted on knife edges, and that the magnetism from the consequent
pole of the magnet will act upon the armature and thus tend to maintain it in proper
position. In other words, a self-contained electro-magnet provided i.e., one having
its armature supported upon itself, such support being hardened knife-edges and the
magnetism assisting in such support, permitting movement of the armature with
minimum friction and with freedom from clogging with dirt.
As the movements of the armature B control the regulation of the carbons (as will
be hereinafter explained in detail), it is very desirable that the armature be so con-
structed as to compensate for varying temperatures and thereby insure the
maintenance of an equal or constant length of arc in cold and warm weather. To
accomplish this the armature is made thermostatic, so that the end thereof which is
,attracted by the pole surrounded by the shunt coil, will always bear the same relation
to said pole regardless of the temperature of the weather to which the lamp may be
subjected; and thus insure the uniform sensitiveness of the regulating mechanism

page_text: nd the length of the arc in all kinds of weather. For the reasons above explained,
he armature B is constructed in two parts, viz: a main part 17 and a smaller
novable part 18, each preferably having inclined meeting edges 20, and these
parts are connected together by a thin plate or blade 21 (preferably of brass),
which is disposed on the back of the armature, being secured at one end to the upper
end of the main part 17 thereof, and at or near the other end to the movable part 18
of the armature. From this construction it is clear that when the brass blade 21
expands or contracts more than the part 17 of the armature, the air gap 22 between
the part 18 of the armature and the lower pole 5 of the magnet, will be extended or
diminished. As slight changes in the air gap 22 will affect the pull of the magnet,
it is apparent that if said air gap can be maintained of irregular proportions under
varying conditions of the temperature to which the lamp is exposed, the maintenance
of an arc of normal length under the varying degree of temperature to which the
lamp may be exposed at different seasons of the year or when placed in different
locations, will be assured. When the shunt is hot, less current will pass. Air gap
should then be smaller to compensate for weakened spool.
In order to prevent armature B and parts actuated by it from moving too suddenly
during the separation and feeding of the carbons, an air pot 23 is provided. It is
desirable that the piston and piston rod 24 of the air pot, be subjected to a minimum
amount of friction, so that the operation of the regulating mechanism shall be
sinooth and easy and for this reason said air pot is disposed in a horizontal position
under the lower pole piece 5 of the magnet, and pivotally supported at one end in a
bifurcated arm 24° depending from said pole piece. A spring 25 also depending
from the pole piece 5, bears against the pivoted end of the air pot at a point below
the pivotal support of the latter, and said air pot is thus yieldingly supported in a
horizontal position, permitting the plunger and its rod to move smoothly and without
binding in the least when the end of. the armature, to which the plunger rod is
attached, moves in the arc of a circle. The connection between the plunger rod and
armature is formed by an arm 26, which may, if desired, be a continuation of the
brass plate 21. A hood or casting 27 is secured to the underside of the top a of
casing A at or near one side thereof and is made with a binding post 28 for the
reception of the negative leading-in-wire of the lamp. The hood is also made with a
binding post 28 into which one end of a conductor 29 is inserted, the other end
of said conductor being attached to the switch arm 30 of a manual cut-out, said
switch arm being adapted to engage a contact plate 31 secured to the binding post 32
to which the positive leading-in-wire is connected. Thus it will be seen that by
moving the switch arm 30 into contact with the plate 31, the lamp will be short-
circuited.
A
A conductor 33 extends from the positive binding post 32 to the coarse wire
coil of the magnet and from said coil, a conductor 34 extends to the upper
carbon holder. A conductor 35 is attached to the conductor 33 and to a binding
post 36 secured to but insulated from the armature B. A coil 37 of low resistance is
attached at one end to the binding post 36 and at the other end to a casting 38.
contact plate 39 is loosely attached to the casting 38 and electrically connected
5 therewith, said plate being adapted to engage a contact arm 40 projecting from
the casting 27 which forms the negative binding post. Thus when the plate 39 and
arm 40 are in contact a shunt circuit of low resistance around the magnet
will be closed, the purpose of which is to cut out the lamp should it be faulty and
refuse to operate. This low resistance shunt is preferably so constructed as to offer
0 somewhat, more resistance to the passage of the current than the circuit through the
coarse wire and the carbons when the current is first turned on (the carbons being
normally in contact), so that if the lamp is. not faulty but in condition to operate
properly, the coarse wire end of the magnet will be energized and attract the upper
end of the armature, thus opening the low resistance shunt and allowing all the
35 current (except a minimum amount which will pass through the shunt fine wire coil),
to flow through the coarse wire coil and the carbons, the same movement of the
armature serving to separate the carbons and establish the arc through the medium

page_text: of the clutch devices and connections hereinafter described. One end of the fine
wire coil 3 is connected with the conductor 33 from the positive binding post of the
lamp and the other end of said fine wire coil is connected with the negative binding
post of the lamp.
Two rods 41, 42, are secured at their upper ends to the hood or casting 27 and at
their lower ends to the floor of the casing, the rod 41 being made tubular. A cross
head 43 is disposed between the rods 41, 42 and provided with rollers 44, to run
on said rods.
An arm 45, secured to and insulated from the cross head 43, projects laterally
therefrom and to the free end of said arm, the upper carbon holder 46 is loosely
connected. A clutch blade 47 is secured to the cross head 43 and, depending
therefrom, passes through the floor of the casing and enters a hollow flat shield which
constitutes the arm C of the lamp.
A rod 48 is adapted to have a vertical movement in the shield or arm C and the
tubular rod 41. One end of a chain 49 is attached at one end to the upper end of
the rod 48 and, after passing over a pulley 50 mounted in the hood or casting 27,
said chain is attached at its other end to the cross head 43. To the lower end of the
rod 48 a slide or bracket 51 is attached and adapted to be guided in ways 52 at the
front edge of the shield or arm C.
To the slide or bracket 52, a holder 53 for the lower carbon is loosely attached.
In order to insure the maintenance of the lower carbon in proper relation to the
upper carbon, a guide 55 is provided. This guide consists of two arms 56 pivotally
attached to the lamp arm and of a length to project beyond the carbon, a roller 57
being mounted in the free ends of said arms and adapted to bear against the carbon.
The length of the guide is such that it will normally assume a downward inclined
position and the weight of the roller 57 will cause the same to bear against the
car hon with sufficient pressure to retain the upper part of the carbon in a socket
piece 58 secured to the lamp arm C.
It will be seen that when the crosshead 43 moves, the carbons will be made
to approach or recede from each other according to the direction of movement of
said cross head. A friction clutch D is adapted to engage the clutch blade 47 and in
order to perimit, the carbons to feed, the clutch will be operated to permit the cross
head to descend and thus cause the carbons to be fed by the gravity of said cross head
and attached carbon holder and upper carbon. In order to ensure the overbalancing
by these parts of the lower carbon, its holder and intermediate connections, the
cross head is provided with a weight 54. This weight is preferably composed of a
box containing shot or other small particles whereby the weight can be readily
adjusted.
The
In constructing the clutch D I employ a yoke 59 having an arm 60 to engage a
stop 60° on the floor of the lamp, and in this yoke the two jaws 61, 62 of the clutch
are mounted and provided with flat inner faces to engage the clutch blade 47.
jaw 61 is provided at its edges with ears 63 which are perforated at their free ends
for the free passage of a rod 64, the latter being secured at its ends to the yoke 59.
The jaw 62 of the clutch is disposed between the ears 63 and provided on its back
with an enlargement 65, the upper face 66 of which is adapted to ride on the fixed
rod 64. The under face of the enlargement 65 is made with a recess 67 (preferably
V-shaped) and in this recess, a hook-shaped tongue 68 projecting from the yoke 59
bears. The extreme end of the tongue 68 bears in the bottom of the recess while
the forward face 69 of said tongue is adapted to bear against the forward wall 70 of
the recess 67. Thus it will be seen that when the inner end 71ª of the yoke 59 is
raised the movable jaw will be forced toward the clutch blade and the latter will be
clamped between the two jaws 61 and 62. In connecting the clutch D and armature B,
a metal bar or weight 71 is provided at its lower end with a hook 72 to engage the
inner end of the yoke 59 and to the other end, a coupling 73 is attached. A plate 74
is attached at one end to but insulated from the coupling 73, and at its other end,
said plate is pivotally attached to an arm 75 projecting from the armature B at

page_text: a point in proximity to the center of the latter. The bar or weight 71 also tends
to move the arinature when the latter is released by the coarse wire magnet.
The holder 76 for the globe 77 is provided internally with a socket piece 78
adapted to receive the lower end of the lamp arın C and be retained in position
thereon by means of a set screw 78". The globe and holder can be moved vertically
to facilitate the trimming of the lamp by loosening the screw 78ª, but will be
prevented from falling by the engagement of said screw with a shoulder 79 at the
lower end of the lamp arm C. The globe holder is provided with a hinged ash
receiver 80 provided with a locking device 81. In order to prevent the entrance of
rain, snow and insects into the globe, a cover 82 is provided therefor and secured to
the lamp casing. The cover 82 is made with a central hole through which the upper
carbon passes and to one side of this hole the cover is made with an opening
appreciably larger than the lamp arm for the accommodation of the latter. The
opening in the cover is closed by an insulated plate 83 provided with a slot for the
passage of the lamp arın. The cover 82 is provided with a depending flange 84
adapted to receive a ring 85 on the upper edge of the globe and the conuection of
the globe and cover is thus made sufficiently tight to prevent the entrance of rain,
snow and insects into the globe. The ring 85 also serves as a convenient support
for a wire netting 86 placed on the globe, and also to prevent the globe from
breaking.
The lamp operates as follows:-When current first enters the lamp, it will pass
through the coarse wire coil and the carbons, thus moving the armature B, and
opening the low resistance shunt circuit, at the same time operating the clutch
(in the manner above explained) and raising the clutch blade slowly to separate the
carbons and establish the arc.
Should the lamp be faulty and refuse or fail to start, the low resistance shunt
circuit will remain closed and thus cut out the lamp. As the lamp continues to burn
and the are increases in length, the consequent increased resistance in the lamp
circuit will cause more current to flow through the shunt circuit including the fine
wire coil and the armature will be actuated to operate the clutch and permit the
carbons to feed.
Various changes might be made in the details of construction of my invention
without departing from the spirit thereof or limiting its scope and hence I do not
wish to limit myself to the precise details herein set forth.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1st. In an electric arc lamp, a magnet constructed with two salient poles of one
and the same polarity and an intermediate or consequent pole of polarity different
from that of the salient poles, and an armature pivotally supported by the inter-
mediate or consequent pole and adapted to be turned on its fulcrum by the salient
poles, substantially as set forth.
2nd. In an arc lamp, the combination with a magnet having salient poles of like
polarity and a consequent pole of the other polarity, of an armature pivotally supported
between its ends by the consequent pole within the path of the lines of force, said
armature being constructed and adapted to be vibrated by the action of the salient
poles, substantially as set forth.
3rd. In an arc lamp, the combination with an electro-magnet having salient poles
of like polarity and a consequent pole of the other polarity, of a pole shoe on the
consequent pole, an armature having knife edge bearings between its ends on said
pole shoe, said armature being adapted to be operated by the action of the salient
poles of the magnet, substantially as set forth.
4th. In an arc lamp, the combination with a magnet having salient poles of like
polarity and a consequent pole of the opposite polarity, of a pole shoe secured to the
consequent pole, an armature, a plate. secured to the armature centrally between its

page_text: ends, and a plate secured to the pole shoe and having a knife edge to receive the
under edge of the plate on the armature, substantially as set forth.
5th. In an ac lamp, the combination with a magnet having salient and conse-
quent poles, of a pole shoe secured to the consequent pole, arms projecting from the
ends of the said shoe, an armature, a steel plate secured to the armature approxi-
mately centrally between its ends, a steel plate secured to the shoe and having a
knife edge to receive the steel plate on the armature, and a steel plate on the arma-
ture, having knife edges to bear against the arms projecting from the shoe,
substantially as set forth.
6th. The combination with a magnet, of an armature made in separate sections
and a yieldable thermostatic strip secured to and connecting said sections, substan-
tially as set forth.
7th. In an arc lamp, the combination with a magnet, of an armature pivotally
supported between its ends and adapted to be actuated by the poles of said magnet,
Baid armature being made in two parts connected together by a thermostatic strip,
substantially as set forth.
8th. In an arc lamp, the combination with a magnet, of an armature made in two
parts, the meeting ends of said sections being inclined, and a yieldable thermostatic strip
secured at one end to one end of one section of the armature and at the other end to
the other section of the armature, substantially as set forth.
9th. In an arc lamp, the combination with a coarse wire magnet and the carbons
in series therewith, of an armature, a low resistance carried by said armature and
included in a shunt circuit around said magnet, and a switch included in said shunt
circuit and operated by said armature, substantially as set forth.
10th. In an arc lamp, the combination with a coarse wire magnet and the carbons
included in series therewith, of an armature, a low resistance secured to and carried
by said armature and included in a shunt circuit around the magnet, a contact arm
secured to a terminal of the lamp, and a contact block or plate carried by the
armature and adapted to engage said contact arm, substantially as set forth.
11th. In an arc lamp, the combination with a magnet, its armature and carbons,
of a horizontally disposed air pot having its plunger rod connected with said
armature, one end of said air pot being pivotally supported, and a spring fixed at one
end and bearing at its free end against the pivoted end of the air pot at a point below
said pivotal support, substantially as set forth.
12th. In an arc lamp, the combination with a magnetand its armature, of a vertically
movable cross head, an upper carbon holder carried thereby, a movable carbon holder,
flexible connections between the cross head and lower carbon holder, a clutch blade
attached to the cross head, a clutch connected with the armature, and an adjustable
weight secured to the cross head whereby to insure the proper overbalancing by the
cross head, of the lower carbon holder and attached devices, substantially as
set: forth.
13th. In an are lamp, the combination with a magnet having salient and
consequent poles, and a vertically movable cross head, of an armature pivotally
supported between its ends by the consequent pole of the magnet, upper and lower
carbon holders connected with said cross head, a clutch blade connected with said
cross head, a clutch and connections between said clutch and armature, substantially
as set forth.
14th. In an are lamp, the combination with a magnet and its armature, of a
weighted connection between said armature and said clutch, said weighted connection
being adapted to transmit motion from the armature to the clutch and also to move
said armature when released by the magnet, substantially as set forth.
15th. A clutch comprising a yoke having an inwardly projecting tongue, a jaw
pivotally supported within said yoke, and a movable jaw a tapted to be engaged and
moved toward the pivoted jaw by said tongue, substantially as set forth.
16th. A clutch comprising a yoke, a jaw pivotally supported within said yoke, a
moyable jaw having a recessed projection on its back, and a tongue on the yoke

page_text: adapted to enter the recess in said projection on the movable jaw whereby to move
the latter toward the pivoted jaw, substantially as set forth.
17th. In a clutch, the combination with a yoke having an arm projecting
therefrom, and a rod extending transversely through said yoke, of a jaw having ears
pivotally connected to said rod, a movable jaw disposed between said ears, an
enlargement on the back of said movable jaw and adapted to ride against said rod,
said enlargement having a recess in its under face, and a hook shaped tongue
projecting from the said yoke and entering said recess whereby to move the movable
jaw toward the pivoted jaw, substantially as set forth.
18th. In an arc lamp, the combination with the carbons and a clutch, of a magnet
comprising a core, a coarse wire coil on one end of said core included in the lamp
circuit and a fine wire coil on the other end of the core included in a shunt circuit,
a consequent pole between said coils, an armature supported between its ends by
said consequent pole and adapted to be actuated by poles at the respective ends of
said core, and connections between said armature and clutch, substantially as set
forth.
19th. The combination with an arc lamp having a movable lower carbon, of a
guide for said carbon consisting of arms pivoted at one end to the lamp arm and
having a roller mounted in their free ends adapted to bear against said lower carbon,
substantially as set forth.
20th. The combination with an are lamp having a movable lower carbon, of a
guide for said lower carbon, said guide consisting of arms pivoted at one end to the
lamp arm and a roller carried in the free ends of said arms, said arms being of such
length as to project further beyond the carbon than is necessary to cause the roller
to bear against the latter, whereby said roller can have a vertical movement and
prevent the possibility of the carbon binding in its guide, substantially as set forth.
21st. The combination with an arc lamp having a movable lower carbon, of a
guide for said carbon, said guide consisting of pivoted arms and a roller carried by
said arms and a socket piece above said guide, to receive the carbon, substantially as
set forth.
22nd. In an arc lamp, the combination with the lamp casing and lamp arm, of a
globe holder attached to the lamp arm, a globe supported by said holder, a ring
mounted on the upper edge of the globe and having a depending flange, a netting
on the globe and secured to said depending flange of the ring, and a cover for said
globe secured to the casing and having an annular depending flange to receive and
enclose the ring on the globe, substantially as set forth.
23rd. In an are lamp, the combination with the lamp arm, of a globe holder, a
socket piece in said globe holder, adapted to receive the lamp arm and to be moved
vertically thereon and means for retaining said globe holder in a fixed position at
any desired adjustment, substantially as set forth.
24th. In an arc lamp, the combination with the lamp arm, of a globe holder, a
socket piece in said globe holder adapted to receive and be guided vertically on said
lamp arm, a set screw for securing the globe holder in a fixed position on the lamp
arm, and a shoulder on the lamp arm against which said set screw will rest when
the globe holder is lowered, substantially as set forth.
Dated this 23rd day of September 1897.
HERBERT HADDAN & Co.,
Agents to the Applicant, 18 Buckingham Street, Strand, London, W.C.