Year: 1899

page_text: Date of Application, 30th Oct., 1899-Accepted, 10th Feb., 1900
We, THE BRITISH THOMSON-HOUSTON COMPANY LIMITED, of 83, Cannon Street,
in the City of London, Electrical Engineers, do hereby declare the nature of this
invention (which has been communicated to us from abroad by Richard Fleming,
residing at Lynn, in the County of Essex, State of Massachusetts, United States
of America, Electrical Engineer), and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement:-
The present invention relates to arc lamps, and more particularly to those of
the enclosed are type; and has for its object to improve and also to lessen the
cost of their construction, and, to this end, consists in the parts and combination
of parts more specifically pointed out and claimed hereinafter.
In the accompanying drawings, which show an embodiment of the invention,
Fig. 1 is a side elevation of an arc lamp with certain parts in section: Fig. 2 is
a perspective view of the resistance support: Fig. 3 is a detail view of the means
employed to establish connection between the carbon tube and the stationary
parts of the lamp; Fig. 4 is a detail view of the clamp employed to vary the
resistance in circuit with the lamp: Fig. is a perspective view of the lower
carbon holder, and Fig. 6 is a sectional view of a slight modification.
The lamp frame consists of two parts, a rectangular frame A, and a tubular
frame B, made of non-magnetic material; these parts are secured together by
screw threads.
The construction of frame B is best shown in Fig. 2. Formed on the lower
end of the tubular portion B₁ is a shoulder which rests on the upper end of the
frame A, and about the middle of the frame is a second shoulder B³ against
which the plate or flange C of the magnet coil C¹ abuts. With the arrangement
shown, we have found it desirable to assemble the frame and then wind the
magnet coil C¹ thereon, but if desired, the coil C₁ may be separately wound and
insulated.
Extending radially from the frame B are a plurality of pins or projections B³,
forming supports for the insulating bushings D employed to support the coiled
resistance wire E. By varying the length of the pins B3 the number of bush-
ings and consequently the number of turns of the resistance wire, may be varied.
The bushings D are preferably made of some non-combustible material, as
porcelain for example, and aie grooved at D₁ on their outer periphery to receive
the pins B Two layers of resistance wire are shown, and the bushings are,
therefore held by three pins, but the number of layers of wire and pins can be
varied as desired. The bushings are secured in place mainly by the resistance
wire but the pins B3 are so disposed that they tend to clamp the bushing between
them. In Fig. 4 is shown an adjustable clamp for changing the amount of
resistance in circuit with the lamp, which consists of two flate plates a and b

page_text: secured together by the bolt c. Formed integral with the plate a is a lug a¹
adapted to be bent over as shown, for the purpose of holding the nut from turn-
ing. This arrangement is a desirable one for it permits the adjustments to be
made quickly, it occupies only a very small amount of space, and it is not
dependent for its efficiency upon the condition of the resistance wire, as it
readily adjusts itself.
Formed integral with the upper end of the frame is a platform F arranged to
form a support for the lamp terminals G and H, and also for the switch L.
Extending upward above the platform and formed integral with the frame are
two lugs J from which the lamp may be suspended.
The tubular frame B is cut away at B4 to permit the flexible connection K to
move up and down as the position of the carbon tube changes, due to changes in
field strength of the magnet coil C₁. The construction of the flexible con-
nection is best shown in Fig. 3, wherein L represents the carbon tube K¹ a
thin metal band surrounding the tube and clamped thereto by a bolt K2 and K³
the insulated flexible cable which extends from the binding post H to the clamp.
The up-and-down movement of the tube is comparatively slight, and the con-
nector K is so flexible that it offers practically no opposition to the movement.
Surrounding the carbon tube and secured thereto is a cylindrical armature M
for controlling the action of the lamp; the upper end of the armature is tapered
slightly, so that the pull of the armature throughout its range of movement will
be practically constant. Loosely secured to the armature M is a cylinder of a
dash pot N arranged to check the movements of the armature. The piston of
the dash pot is supported by a lug A¹ formed integral with the rectangular lamp
frame A. Supported by the lower end of the carbon tube L is a clutch O arranged
to work directly on the upper carbon P. The clutch, as shown, consists of two
pivoted eccentrics, so arranged that they grip the carbon between them, but
any other form of clutch may be employed if desired.
The upper carbon is provided with a holder or follower P¹, comprising a cylin-
drical body of metal slotted or grooved in the centre to receive the V-shaped
spring P2 In the present instance, the spring is made of wire, and carried by one
end is an insulated button P³ arranged to slide along the inside of the carbon
tube L and push the follower P₁ against the tube in order to establish good
electrical connection between the tube and the upper carbon.
The button P is made of insulating material so that the current will not
heat the spring, thereby destroying the temper. The spring is prevented from
getting out of place at the bottom by the transverse pin P, but the upper ends
are free to adjust themselves with respect to the carbon follower.
In arc lamps having an inner globe which encloses the arc, and an outer
globe surrounding the first named globe, a great deal of the light from the arc is
absorbed by the outer globe. For out of door work it is preferable to provide
an outer globe for protecting the cylinder from rain and wind, but for in-door
work, where the lamp is not subject to moisture and wind, the outer globe may
be dispensed with. This arrangement is a very desirable one on account of the
decrease in the amount of light absorbed and wasted, and by mounting a white
shade or reflector R above the cylinder practically all of the available light may
be utilized. One desirable feature in connection with a lamp having a single
globe is that it runs considerably cooler than lamps having double globes.
The "inner globe" or "cylinder" U may be of suitable design, and is arranged
to fit into a groove U¹ formed in the flat ring U2 which is secured to the bottom
of the frame A. Secured to the plate and extending downwardly are two rods G
forming a support for the yoke G¹, and also arranged to convey current to the
lower carbon.
In order to simplify the construction, a single clamp is provided for both the
lower carbon and the cylinder.
Located within the yoke G¹ is a cylindrical body of metal G³ (see Figs. 1 and 5),

page_text: having a central opening for the reception of the lower carbon, and extending
radially through said body are slots G³ to permit the segmental pieces thus formed
to clamp the carbon. The outer surface of these segmental pieces is tapered, as
shown at G, and this taper engages with a corresponding taper on the yoke G¹.
The lower end of the cylindrical piece G³ is screw threaded, and mounted upon this
screw threaded portion is a combined nut and cylinder holder W. The carbon
holder G³ is prevented from turning by the short screws g which engage with
lugs g formed on the yoke.
The combined nut and holder W is cup-shaped, and extending upwardly there-
from to the bottom of the carbon is a projection W₁ which serves as a stop and
also as a guide in retrimming the lamp. The nut W is in circuit with the lamp
and to prevent injury to persons making contact therewith, a layer of insulat-
ing material W2 is placed over the nut as shown in dotted lines.
When it is desired to re-carbon the lamp, the nut W and the cylinder U are
removed; this loosens the carbon holder and permits the lower carbon to drop
downward and out of the lamp. After new carbons have been inserted in place the
cylinder is slipped into position and the nut W mounted in place and tightened
until the top and bottom edge of the cylinder are firmly seated on the asbestos
washers X and X', which washers prevent the entrance of air into a cylinder at
these points.
Surrounding the upper carbon and located between the bottom of the frame A
and the flat, grooved ring U2 is a gas check or device for preventing the free
entrance of air into the cylinder.
The said device consists of a circular piece of metal having a hub T¹ formed
integral therewith, and formed in this hub are circular air chambers which pre-
vent the free entrance of air around the upper carbon. Since the flat ring U
and the rods G are electrically connected to the lower carbon, it is necessary to
insulate the air-restricting device from the lower parts of the lamp. This is
accomplished by placing a mica washer T3 above the said device and a second
washer T3, below. Connection between the lower carbon and the exterior circuit
is established through the binding post Q and wire Q¹; the binding post Q is
insulated from the lamp frame and gas check T¹, but is electrically connected
with the ring U².
In Fig. 6 is shown a slight modification of the flat ring U2. We have found
that the expansion of the rods G is somewhat greater than that of the cylinder U
and, in consequence, after the lamp gets hot, air will be admitted around the
top of the cylinder. To prevent this, a deep groove U₁ is turned in the flat ring U²
and an asbestos packing a is used as before. We have found that the spaces f
and fi between the cylinder and the sides of the groove act as a check and prevent
the free entrance of air. The carbon life of a lamp having the deep groove, as
shown in Fig. 6, is a few per cent. greater than that of the form shown in Fig. 1.
Surrounding and supported by the lower ends of the casing is a shade or
reflector R, which is so designed that it will reflect the rays of light from the
are and at the same time protect the cylinder, to a certain extent, from accident.
The reflector is supported in place by a split ring S which is retained by the
upturned edge of the casing and the halves of the ring are united by a screw.
Surrounding the upper part of the lamp mechanism is a cylindrical casing Z
made of sheet metal, and situated below this casing is a second and cylindrical
casing Z', slightly smaller in diameter than the first, the arrangement being such
that the two parts will telescope to permit the retrimming of the lamp. Secured
to the upper end of the cylinder is a band or cornice V which surrounds and
protects the resistance wire from dust and dirt and, at the same time, presents a
pleasing appearance. Situated between the two cylinders and secured to the
upper one, is an ornamental band or cornice Y, so arranged that it tapers downward
to the size of the lower cylinder, so that the telescoping feature of the two parts
of the casing is not noticeable. At the lower end of the cylinder is an ornamen-

page_text: tation band or cornice, which is open on its upper end so that it will slip over
the lower part of the cornice Y when it is raised to the position shown in dotted
lines, Fig. 1, for the purpose of trimming the lamp; this permits the lamp to be
somewhat shortened. On the inside of the upper casing Z is a ring Z2, and
when the lower part of the casing is in its normal position the outwardly flaring
flange rests thereon.
When it is desired to retrim the lamp, the cylindrical casing Z¹ and the
shade R are moved upward to the position shown in dotted lines, and as soon
as the nuts Z' strike the under side of the ring Z the casing is given a slight
twist which locks it in place temporarily. To replace the parts the cylinder
is given a slight twist in the opposite direction which release it, and the shade
is lowered to its normal position. It will be seen that this is a desirable arrange-
ment for it permits the shade to be moved out of the way of the trimmer but
does not have to be removed from the lamp.
Having now particularly described and ascertained the nature of our said
invention (as communicated to us from abroad) and in what manner the same
is to be performed, we declare that what we claim is :-
1 In an electric are lamp, the combination of a rectangular frame within
which certain of the working parts of the lamp are mounted, a non-magnetic
tubular frame secured to the rectangular frame, and a plurality of radially
extending arms formed integrally with the tubular frame, and a resistance
mounted between the radially extending arms.
2-In an electric arc lamp, the combination of a rectangular frame, within
which certain of the working parts of the lamp are mounted, a tubular frame
screw threaded to the rectangular frame, a shoulder formed on the tubular
frame against which the spool of the magnet abuts, a magnet wound on a spool
and mounted on the tubular frame, a plurality of radial arms formed integral with
the tubular frame, a resistance coil mounted on the lamp and supported by the
radial arms, and insulating bushings between the arms and the coil.
3-In an electric arc lamp, a support for a resistance comprising a tubular
frame having a central opening for the reception of certain of the moving parts
of the lamp, radial arms for supporting the resistance wire, and a platform for
supporting certain of the fixed parts of the lamp.
4 In an electric arc lamp, the combination of a tubular frame for supporting
the resistance, a platform formed integral with the frame and designed to support
the binding posts, a carbon tube mounted within the frame, and a flexible con-
nection between one of the binding posts and the tube.
5 In an electric arc lamp, the combination of a carbon tube adapted to be
moved up and down as the strength of the operating magnet changes, a carbon
follower mounted within the tube and arranged to establish electrical connection
between this tube and the carbon, and means for forcing the follower against the
tube at least one point.
6 In an electric arc lamp, the combination of a carbon tube, a carbon
follower mounted within the tube and arranged to establish electrical connection
between the carbon holder and one terminal of the lamp, the said follower con-
sisting of a slotted cylindrical piece of metal having a spring pressed insulated
contact for pressing the follower against the surrounding tube.
In an electric arc lamp, the combination of a carbon tube, a tubular
armature for raising the carbon tube which is slightly tapered at its upper end
to give a practically constant pull, a magnet coil for actuating the armature and
a slotted tubular follower which carries the upper carbon mounted within the
carbon tube, said follower being provided with a U-shaped spring carrying an
insulated button which presses the follower against the carbon tube.
8 In an electric arc lamp, the combination of a globe holder; a carbon holder,
and means for simultaneously -clamping the carbon and securing the globe in
position.

page_text: 9-In an electric arc lamp, the combination of a globe or cylinder, a holder
therefor, a carbon holder, and means for tightening the carbon and cylinder
simultaneously the arrangement being such that as the cylinder is forced upward
into place, the carbon holder is drawn down and grips the carbon.
10 In an electric arc lamp the combination of a yoke rods for supporting the
yoke, a tapered carbon holder mounted in the yoke, means for preventing the
holder from rotation, a globe or cylinder and a holder therefor which is screw-
threaded to the carbon holder, the arrangement of parts being such that as the
cylinder is pushed upward against its seat, the carbon holder is drawn downward
and firmly clamps the carbon.
11 In an electric arc lamp, the combination of a yoke, side rods for supporting
the yoke and lower carbon holder, a globe or cylinder which surrounds the yoke,
a holder for the globe electrically connected to the lower carbon, and an insula-
ted covering for the globe holder.
12 In an electric arc lamp, the combination of a frame, a cylinder or globe, a
seat therefor, and means surrounding the upper carbon and located between the
frame and the seat of the cylinder for preventing the free admission of air to the
cylinder.
13--In an electric arc lamp, the combination of a supporting frame, a globe
for enclosing the arc, a seat for the globe making a practically air tight
joint, and a gas check surrounding the upper carbon and located between the
frame of the lamp and the globe seat, the said gas check consisting of a flat
cylindrical piece of metal, having a central hub provided with an air chamber.
14 In a single globe arc lamp, the combination of a frame, a globe, a flat
grooved ring forming a seat for the globe, the said ring being in circuit with
the lower carbon, a gas check located between the frame and the grooved ring,
the said gas check being in circuit with the upper carbon, and insulation between
the frame and the gas check and between the grooved ring and the gas check.
15 In a lamp of the enclosed arc type, the combination of a cylinder which
encloses the arc, a gas check surrounding the carbon and provided with an air
chamber for preventing the free entrance of air into the cylinder, and a seat for
the cylinder provided with a deep groove into which the end of the cylinder
extends, the said groove being wider than the thickness of the cylinder so that
two chambers are formed which prevent the free entrance of air at that point.
16-In an electric arc lamp, the combination of a cylindrical casing, a second casing
arranged in telescopic relation to the first, a cornice or head located at the top
of the casing, a second cornice situated between the parts of the casing, and a
third cornice which is attached to the lower casing.
17 In an electric arc lamp, the combination of a casing composed of two
cylindrical parts arranged to telescope when it is desired to inspect the working
parts of the lamp, means for holding the parts of the casing together when
telescoped, a cornice between the two parts of the casing, and a second cornice
secured to the lower casing which fits over the first named cornice when in its
raised position.
18 In an electric arc lamp, the combination of a two-part casing capable of
telescoping, a shade carried by the lower part of the casing, a split ring for sup-
porting the shade, and a flaring end on the lower part of the casing for retaining
the ring, the relation between the parts being such that the shade is raised when
the parts are telescoped.
19 In an electric arc lamp, the combination of a coiled resistance situated at
the top of the lamp, and means for varying the amount of resistance included
in the circuit, which consists of two flat metal plates adapted to grip the turns
of the resistance wire between them, a bolt for holding the plates together, and
a lug formed on one of the plates for preventing the nut of the bolt from turning.
20 As an article of manufacture, a carbon holder consisting of a cylindrical
body of metal having a straight bore, with radial slots dividing the said body into
segmental pieces, a tapered portion adapted to engage a corresponding tapered

page_text: portion of the lamp, and a screw threaded portion at the end of the cylindrical
body for the purpose of adjusting the holder.
Dated this 25th day of October 1899.
THE BRITISH THOMSON-HOUSTON CO. LTD.,
J. J. MANHEIM,
A. R. MONKS,
Directors,
ALFRED CLEMENTS,
Assistant Secretary.