Improvements in Electric Arc Lamps.
Year: 1897

page_text: Date of Application, 16th Mar., 1897-Accepted, 1st May, 1897
VUMI LEIM DI MUIFICATION.
Improvements in Electric Arc Lamps.
1, THOMAS EDGAR ADAMS, Cleveland, Ohio, United States of America,
Electrical Engineer, do hereby declare the 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 :-
My invention relates to an improvement in electric arc lamps, and more
particularly to such as employ an inner or arc-enclosing globe.
One object of the invention is to provide an electro-magnet, so constructed that
its armature shall be capable of long range of movement and so that the "pull"
of the magnet shall be uniform throughout the entire range of movement of the
armature.
A further object is to so construct the motor mechanism of an arc-enclosing
electric arc lamp, as to avoid the expense incident to the use of solenoids, and to so
construct an electro-magnet having a pivotal armature, that said armature shall
have a length of movement adequate to effect the wide separation of the carbons;
be steady and uniform throughout its entire throw, and not be susceptible, in any
degree, of "side pull."
A further object is to construct an electro-magnet for an arc lamp in such
Imanner as to reduce the length of the magnet circuit to a minimum, with an
adequate cross section of wire in the magnet coil to properly energize poles of
extended surface, whereby to actuate an armature accurately and uniformly
throughout a long range of movement.
A further object is to so construct the electro-motor mechanism of an electric
arc lamp, that it shall be self-contained, that is to say, so that the armature and
air pot shall be supported by the magnet structure and the whole fastened within
the casing at a single point, thus avoiding possibility of binding between the parts
of the electro-inotor mechanism due to expansion and contraction.
A further object is to mount the armature of the magnet, in such firm, durable
and frictionless manner, that it will respond to the slightest changes of current
flowing through the coil of the maguet.
A further object is to so mount a rheostat upon an electric arc lamp casing as to
effect ample insulation and easy adjustment.
A further object is to mount a rheostat on an electric arc lamp casing in such
manner that it shall be waterproof and durable and comparatively cheap to construct.
A further object is to provide means whereby to readily adjust the cover of the
inner or arc-enclosing globe.
A further object is to construct and arrange the negative carbon bracket in such
manner that it will serve to support the cover of an inner or arc-enclosing globe.
A further object is to so construct and arrange the cover of an arc enclosing
globe that it can be adjusted laterally whereby to insure the alignment of the
upper with the lower carbon.
A further object is to so construct and arrange a cover for an inner or arc-
enclosing globe, that it shall be very light and one which will readily reach a
temperature practically equal to that of the arc-enclosing globe, whereby to avoid
accidental breaking of the globe, which would be likely to occur if its upper edge
be subjected to a cold cover while the lower portions are becoming heated by the
arc when the lamp is being started.
A further object is to provide simple and efficient means for lowering and
sustaining the large outer globe to facilitate trimming the lamp.

page_text: With these objects in view my invention 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 an elevation of an electric arc lamp embodying my improvements.
Figure 2 is an enlarged detail view of the magnet, its armature and attached
parts.
C
Figure 3 is a detail view illustrating the rheostat.
Figure 4 is a detail view illustrating the cover of the arc-enclosing globe and
the bracket which supports it.
Figures 5 and 6 are views illustrating the outer globe holding devices, and
Figures 7, 8, 8 and 9, are detail views.
A represents a casing comprising a top a, a floor or bottom 6 and upright
connecting walls c.
A plate 1 is secured to but insulated from the under face of the top or cover a
of the casing and made with a binding post 3 for the reception of the minus
leading-in wire of the lamp. Another plate 4 is secured to and insulated from the
lamp floor and made with an upwardly projecting sleeve 5 for the reception of the
lower end of a rod 6, the upper end of which is secured to the plate 1. Another
rod 7 is secured at its upper end to the plate 1 and at its lower end, said rod 7 may
be made to project through the plate 4. A cross head 8 is disposed between the
.rods and 7 and provided with rollers to run on said rods. An arm 9 is secured
to but insulated from the cross head and at its free end supports the holder 10 for
the upper carbon 11. A clutch blade 12 is secured at its upper end to the cross
head and projects loosely through the floor of the lamp and enters a flat lamp arm B
secured to and insulated from the bottom of the lamp. In order to insure the free
movement of the clutch blade within the lamp arm, said blade is provided with
rollers 13, 14, disposed at right angles to each other.
The blade 12 passes through and is engaged by a clutch 15 of any preferred
form of construction, and the latter is connected with the armature of the separating
and feeding magnet in a manner presently explained.
The separating and feeding magnet C of the lamp is made with a coil of com-
paratively large wire and is provided with pole-pieces 16, 17, at the respective
ends, said magnet being secured at one end to the top of the lamp. The upper
pole piece 16 projects laterally some distance from the core and coil and is bent
down slightly so as to present an extended face to the broadened end 18 of the
armature 19. The armature is made L-shaped and is pivotally connected to the
rear or outer part of the short pole piece 17 of the magnet and is therefore
attracted by both poles of the magnet. In order to reduce the friction of the
pivotal bearing of the armature to a minimum so that the armature will respond
quickly and accurately when actuated by the magnet, a steel plate 20 having a
Knife edge is secured to the end of the short arm of the armature and bears against
the beveled edge of a steel plate 21 secured to the pole piece 17 and also against
the knife edge of a plate 22 secured to said pole piece 17. To prevent the armature
from falling when no current is passing through the lamp and the magnet is inactive,
a block 23 (preferably brass) is secured to the pule piece 17 and is provided_with a
flange 24 which projects under the end of the short arm of the armature. Lateral
displacement of the armature is prevented by means of lugs 25, projecting from
the ends of a plate 26 secured to the plate 20.
An arm 27 is secured at one end to the longer pole piece 16 of the magnet and
projects outwardly and downwardly therefrom, the free end of said arm having
ears 28 which constitute a stop to limit the outward movement of the armature
when no current is flowing through the lamp. An air pot 29 is pivoted at its
upper end to the free end of the arm 27 and the plunger rod 30 is pivotally
connected to the free end of an arm 31 secured to the lower portion of the
armature.
A plate or arm 32 is also pivoted to the free end of the arm 31 and depends

page_text: therefrom, the lower end of said plate or arm 32 being connected to and insulated
from a coupling 33. A rod 34 is adjustably connected at its upper end to the
coupling and at its lower end is attached to the clutch 15. From this construction
and arrangement of parts, it will be seen that when the magnet is energized,
motion will be transmitted by the armature, to the clutch and cause the latter to
grasp the clutch blade 12 and raise it. The clutch blade being connected with the
cross head 8 which carries the upper carbon, the latter will be raised when the
armature is actuated as above explained, and the wide separation of the carbons
will be effected.
The plate 4 in the bottom of the lamp is made with a hole in line with the
sleeve for the reception of a rod or bracket 35 which depends from the lamp
floor and is rigidly held in place by means of a screw 36 passing through the wall.
of the sleeve 5. The lower end of the rod or bracket 35 is bent to form a short
horizontal arm 37, for the reception of the lower carbon holder 38. The carbon
holder 38 comprises a fixed jaw 39 and a movable jaw 40. The fixed jaw is made
with a short sleeve or perforated hoss 41 for the reception of the short arm 37 of
the rod or bracket 35, to which it is secured by means of a screw 42. One end of
the movable jaw 40 is bifurcated so as to embrace the sleeve or boss 41 and the
prongs 43 of said movable jaw have a pivotal bearing against pins 44 which project
from the sleeve or boss 41 at diametrically opposite points. The outer end of the
movable jaw is made with a hole for the free passage of a screw 45, which enters
a screw-threaded hole in the end of the fixed jaw. In this manner a very simple
and efficient holder for the carbon is constructed.
The lower extremity of the lamp arm B is made with a vertically disposed sleeve
or perforated boss 46 in which a coiled spring 47 is seated. The spring 47 projects.
above the sleeve or boss 46 and at its upper end is provided with a socket piece 48
for the reception of a tit or enlargement 49 at the bottom of an arc-enclosing
globe 50. The spring 47 serves to force the open upper end of the globe against
a cover 51 of thin, light metal. The cover 51 is made with a hole between its
centre and its periphery for the passage of the rod or bracket 35 to which said
cover is adjustably secured by means of a set screw 52. The cover 51 is made
with a central opening surrounded by an annular upwardly projecting flange 53,
which latter is screw threaded internally for the accommodation of a screw threaded
bushing 54, through which the upper carbon of the lamp passes.
It will be seen
that by loosening the screw 52 the cover can be adjusted vertically on the rod or
bracket 35 to properly adapt it to the length of globe or to regulate the pressure
exerted by the spring 47 in forcing the globe against said cover. The cover 51
can also be moved laterally on the rod or bracket 35, whereby to adjust the upper
carbon and insure its alignment with the lower carbon.
It has been found in practice that when the upper edge of the globe is allowed
to remain cold, while the lower portion is becoming heated when the arc is being
formed, there is liability of the globe breaking or cracking owing to the unequal
expansion of the glass. By making the cover 51 thin and light, it will become
heated almost as quickly as the glass globe and the upper edge of the latter
will not be kept cool during the starting of the lamp; there will be very little
liability of the globe being cracked or broken during the initial operation of the
lamp.
To permit the removal of the arc-enclosing globe when the lamp is to be trimmed,
the socket piece 48 and spring 47 will be moved out of line with the globe, when
the latter can be readily removed.
A tubular extension 56 is secured to and depends from the boss or sleeve 46 on
which an externally screw threaded sleeve 57 is loosely mounted. Two disks 58, 58
having screw threaded openings are placed on the sleeve 57 and adapted to clamp
the lower end of a large globe 60 between them, suitable gaskets or washers 59 being
disposed between the disks and the globe and the sleeve 57 projecting through the
opening in the bottom of the latter. The globe 60 and the sleeve 57 are held in
position by the engagement of the lower end of the latter with a flange 61 on a cap

page_text: or knob 62 screwed on the lower end of the tubular extension 56. To the cap or
knob 62, a rod 63 is screwed and adapted to project up through the tubular
extension 56 and through the hollow boss or sleeve 46. The upper end of the
rod 63 is made with a head 64, which, when said rod is lowered, is adapted to
engage a flange or shoulder 65 at the lower end of a short tube 66 disposed within
the tubular extension 56, the upper end of said tube 66 being made with a
shoulder 67 to engage the tapering interior of the lower part of the tubular
extension 56. From the above it will be seen that extensible holding devices
are provided for the outer globe and that when the cap or knob 62 is unscrewed
from the tubular extension 56, the sleeve 57 and the outer globe 60 can be
lowered.
If desired a cover 69 may be provided for the outer globe, said cover being
secured to the under side of the lamp casing. If a larger outer globe is desired,
this cover may be omitted.
On the top of the casing A of the lamp, a grooved ring 70 is horizontally
disposed for the accommodation of a rheostat, which, in the present instance, is
composed of a coil 71 of resistance wire, encircled by an annular series of tubular
insulators 72 which have their bearings against the grooved ring 70. One end of
the coil 71 is connected to a binding post 73. One end of a flexible conductor 74
(covered with heat proof material, such as asbestos), is adjustably, attached to the
resistance coil, at or near its other end. by means of a cylindrical block 74" and a
screw 74, a washer 74° being inserted between the head of said screw and the
resistance wire, and the opposite end of said conductor is connected to a binding
post 75. A cap 76 is disposed over the rheostat and rests on lugs 77 projecting
upwardly from the top of the casing so as to leave a space between said cap and
casing for the circulation of air. An annular flange 78 projects upwardly from
the cap, around the opening therein, and around this flange, the cap is made with a
number of lugs 79. On these lugs, a dished plate 80 rests so as to permit the entrance
of air under it. The plate 80 is made with a central opening for the accommodation
of an enlargement 81 on the lamp casing, and said plate and cap are retained in
position by means of a screw 82 which enters said enlargement 81. From this
construction and arrangement of parts it will be seen that the rheostat is mounted
directly on the lamp and not separately therefrom as has been heretofore proposed.
A rheostat constructed and arranged as above explained is thoroughly insulated;
easy to adjust; practically waterproof; durable; cheap to construct; not liable to
become grounded or short circuited; can withstand heat and moisture and will be
thoroughly ventilated.
A binding post 83 is secured within the lamp casing for the reception of the
positive leading-in wire and to this binding post, contact plates 84 are secured and
adapted to be engaged by a manually operated switch arm 85, the latter being
pivotally connected to the lamp casing and provided at its outer end with a knob.
A conductor 86 is attached at one end to the switch arm 85 and at the other end
to the binding post 73 of the rheostat. To the other binding post of the rheostat,
a conductor 87 is attached, the other end of said conductor being connected with
one end of the coil of the magnet. The other end of the coil of the magnet is
connected, by means of a conductor 88, with the upper carbon holder. The
current flows from the lower carbon holder through the rod or bracket 35 to the
rod 6 and thence to the plate 1 and negative binding post 3 of the lamp, the cross
head 8 and rod 7 also serving as a portion of the negative conductor of the lamp.
In electric are lamps in which the arc is enclosed by an air tight globe, quite a
long are can as is well known be formed and maintained. For establishing such
large arcs, electro magnets as commonly constructed are unsuitable and solenoids
have been used, but the latter are objectionable on account of the large amount of
wire necessary to insure their proper operation. The construction and arrangement
of electro-magnet herein described, will result in an adequate movement of the
armature to effect the formation of a long are; will exert a perfectly even pull on
the armature, and as the magnet circuit is perfect, owing to its being short and of

page_text: ample cross section and the poles having large surface area, but little wire will be
required; there will be no side pull of the armature and friction between the
working parts will be reduced to a minimum.
My improved electro-motor mechanism is self-contained; i.e. the armature and
air pot are carried by the pole pieces of the magnet and the whole fastened in the
lamp casing at a single point. The mechanism will not, therefore, be affected
by unequal expansion and contraction and consequent binding and changing of
adjustment.
My improvements are simple in construction; accurate in operation and effectual
in all respects, in the performance of their functions.
Various slight 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, but,
Having now particularly described and ascertained the nature of this inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:
1. In an electric arc lamp, the combination with the carbons and a clutch, of an
electro-magnet having pole pieces at both ends, one of said pole pieces having an
inclined extension, an L-shaped armature, connections between said armature and
clutch, said armature having the extremity of its shorter arm pivotally connected
to the shorter pole piece of the magnet and adapted to be attracted thereby, and
the longer arm of said armature having an end face to be attracted by said
inclined polar extension, whereby to effect a long and steady pull on said armature,
substantially as set forth.
2. The combination in an arc lamp, of a rod depending from the frame thereof,
a vertically and laterally movable arc-enclosing globe cover mounted on said rod,.
and means for normally retaining said globe cover in a fixed position with relation
to the globe.
3. The combination in an arc lamp, of a rod movably attached to the lamp
casing, an arc-enclosing globe cover movably mounted on said rod, means for
normally securing said cover in position, and a carbon holder at the lower end of
said rod, substantially as set forth.
4. The combination in an are lamp, of a rod depending from the lamp casing, an
arc-enclosing globe cover having a hole therein for the passage of the upper
carbon, a perforated enlargement near the periphery of the cover for the passage
of said rod and a set screw passing through the wall of said enlargement and.
engaging said rod, substantially as set forth.
5. In an electric arc lamp, the combination with a magnet, a pivoted armature
and an air pot, of an arm projecting from said magnet and serving as a stop for
said armature and a support for said air pot, substantially as set forth.
6. In an electric arc lamp, the combination with a magnet and an armature
pivoted at one end to one end of the magnet, of an arm secured to the other end of
said magnet, an air pot attached to said arm and a connection between the plunger
of said air pot and the armature in proximity to the pivoted end of the latter,
substantially as set forth.
7. In an electric arc lamp, the combination with a magnet having poles at its.
respective ends, of an L-shaped armature pivotally connected to one pole and
adapted to be actuated by both poles and an air pot attached to one end of said
magnet and having its plunger connected with the L-shaped end of the armature,.
substantially as set forth.
8. In an electric arc lamp, the combination with a magnet having poles at its
respective ends and an armature adapted to be actuated simultaneously by both of
said poles, of knife edge hinge pieces for the armature on the magnet and armature,
bearings for said hinge pieces secured to the magnet and armature and a support
on the magnet projecting under the armature, substantially as set forth.
9. In an electric arc lamp, the combination with a magnet having pole pieces at.

page_text: both ends, of an armature pivotally supported by one of said pole pieces and
adapted to be actuated by both of them, an arm projecting from the pole piece
adjacent to the free end of the armature, an air pot attached to said arm, an arm
projecting from the armature near the pivoted end of the latter, the plunger of the
air pot being attached to the arm on the armature, a clutch and a connection
between said clutch and the arm on the armature, substantially as set forth.
10. In an electric arc lamp, the combination with the lamp casing and the
negative binding post, of a plate in the floor of the ca-ing having a hole therein, a
tubular rod electrically connecting said plate with the negative binding post, a rod
or bracket having its upper end movably inserted in the lower end of said tubular
rod, said rod or bracket depending below the lamp floor and having a carbon holder
at its lower end, means for normally securing said rod or bracket in position, and au
arc-enclosing globe enclosing the lower portion of said rod or bracket and the carbon
holder, substantially as set forth.
11. In an electric arc lamp, the combination with a rod or bracket depending
from the lamp casing and having a lateral arm at its lower end, of a carbon holder
comprising a rigid and a movable jaw, the rigid jaw having a perforated boss to
receive the lateral arm on the rod or bracket, a set screw passing through the wall
of said boss and engaging said lateral arm, pintles on opposite sides of said boss,
prongs projecting from the movable jaw and having pivotal bearings on said pintles,
and a screw passing loosely through the free end of one jaw and entering a screw.
threaded hole in the free end of the other jaw, substantially as set forth.
12. In an electric arc lamp, the combination with the casing thereof, of a grooved
ring located on the top of said casing, an annular series of insulators having
bearings in said grooved ring, a resistance coil passing through said insulators, and
a cap covering said ring, coil and insulators, substantially as set forth..
13. In an electric arc lamp, the combination with the casing thereof having a
central projection, of a rheostat located on said casing, a cap covering said rheostat
and having a central opening, a plate over said opening and a screw entering the
projection on the casing and retaining said plate and cap in position, substantially
as set forth.
14. In an electric arc lamp, the combination with a casing having lugs on its top,
of a rheostat located on said casing, a cap covering said rheostat and resting on said
lugs, said cap having an opening in its center, lugs on said cap surrounding the
opening, a dished plate resting on said lugs on the cap and covering said opening in
the latter, and means for holding said cap and plate in position, substantially as set
forth.
15. In an electric arc lamp, the combination with the casing, a lamp arm and a
cross head, of a clutch blade secured to said cross head and entering said arm, a
clutch to grasp said blade, means for operating said clutch, and two wheels mounted
at the lower end of said blade and at right angles to each other, substantially as set
forth.
16. In an electric arc lamp, the combination with the casing and a lamp arm, of
arc-enclosing globe, a rod or bracket depending from the lamp casing and
tering said globe, a cover for said globe movably mounted on said rod or
oracket, means for normally securing the cover to the rod or bracket, a coiled
spring seated in the lower end of the lamp arm and a socket piece secured to the
upper end of said spring and adapted to receive the lower end of the globe,
substantially as set forth.
17. In an electric arc lamp, the combination with the lamp arm, of an extension
depending from the lower end of said arm, an externally screw threaded sleeve
mounted on said extension, disks on said sleeve for attaching a globe thereto, and
a cap removably attached to said extension and adapted to support said sleeve and
the globe attached thereto, substantially as set forth.
18. In an electric arc lamp, the combination with the lamp arm, of a tubular
extension depending from the lower end thereof, a sleeve loosely mounted on said
extension, means for attaching a globe to said sleeve, a cap removably attached to

page_text: said extension and adapted to support said sleeve and globe and means for lowering
said cap and supporting said sleeve and globe in a lowered position, substantially as
set forth.
19. In an electric arc lamp, the combination with the lamp arm, of a tubular
extension depending therefrom, a sleeve loosely mounted on said extension, means
for attaching a globe to said sleeve, a cap removably attached to said extension and
adapted to support said sleeve and globe, a rod secured to said cap and projecting
through the tubular extension, a head on said rod, a tube within said extension and
having a shoulder at one end to receive said head, a shoulder at the other end of
said tube, and a tapering portion within said extension to receive said last mentioned
shoulder on said tube, substantially as set forth.
20. In an electric arc lamp, the combination with the lamp casing and a rheostat
thereon, of a binding post, a flexible conductor covered with heat-proof material,
attached at one end to the binding post and having a block at the other end, said
block being inserted into the end of the rheostat and a screw entering said block and
bearing against the rheostat, substantially as set forth.
Dated this 16th day of March 1897
HERBERT HADDAN & Co.,
18, Buckingham Street, Strand, London, W.C., Agents to Applicant.