Improvements in Arc Lamps.
Year: 1896

page_text: COMPLETE SPECIFICATION.
Improvements in Arc Lamps.
I, JOHN ALBERT SEAVERNS, of 9 Harris Avenue, Electrician, of Boston, in
the County of Suffolk, State of Massachusetts, United States of America, 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:-
This invention relates to arc lamps particularly such as are designed for pro-
jection, and where a positive feed is of the most essential importance in order to
maintain a steady light.
My improvements are embodied primarily in two carbon holders which are fed
forward by a clock mechanism. This time piece, it is to be understood, is to be
adjusted with regard to its rate of running in such manner that, providing the
electric current is constant and the carbons homogeneous throughout, an electric arc
of a uniform length shall be continuously maintained. But because these two
conditions, the uniformity of the current and the homogeneity of the carbon,
never co-exist, I have provided a controller. In this device is embodied the second
portion of my invention, whereby a coil, through which the supply current to the
lamp is caused to pass, serves to change the regular predetermined rate of said
clock mechanism, and as a consequence either cause said rate to be accelerated or
be retarded in conformity with the then existing conditions, such as may occur
through variations in the strength of the current or in the rate of impairment of
the carbons, in order that the arc shall be continuously maintained.
Thirdly, in dividing the train of the clock mechanism into two groups of parts
which shall not have positive connection, and further that said two trains shall be
united by some friction device. Fourthly, in weighting the balance wheel whereby
the feeding mechanism is always in readiness to operate. Other features and
prominent characteristics will be hereinafter fully shown and described.
The drawings represent in Fig. 1 a longitudinal vertical sectional elevation of
an electric arc lamp embodying my invention. Fig. 2 is a rear end elevation.
Fig. 3 is an enlarged side view in part. Fig. 4 is a horizontal section on line 1. 1.
in Fig. 1. Fig. 5 is an enlarged section on line 2. 2. in Fig. 3. Fig. 6 is a side
elevation of a modified form of controller mechanism.
The prominent features of this lamp comprise a closed metallic box 2 suitably
mounted on a movable support 20. In said box is secured a frame or casing 21 to
contain the train of an ordinary time piece, while two obliquely disposed carbon
holders 3. 3' externally disposed receive the carbons 4. 4' respectively positive and
negative. The train of the time piece is indicated at 5. 51 52 53 5+ 5° 5° while the
escapement wheel is at 6, and the balance wheel at 7. The arbor 8 carries the
main spring and likewise serves as the pivot for the casing 21 of the time piece
which oscillates thereupon but within the box 2 at certain designated times either
when the lamp is lighted or extinguished. The feed movement of the carbon
holders may be effected manually or otherwise by means of two toothed racks 9. 9¹
in parallelism which intermesh with two pinions 10. 10' affixed upon the arbor 8,
the diameter of said pinions being so proportioned that the increased impairment
or waste of the positive carbon with respect to the negative carbon in direct current
(this being equal in alternating current) is compensated for and the are is main-
tained relatively at a fixed point. In the trimming of the lamp or in the act of
renewing the carbons, it is to be understood that the holders have necessarily

page_text: approached, hence they must be separated. But in order so to do with the ordinary
train arrangement of a'clock the same lapse of time would be required to separate
them as was required for their approach. Hence, the train is sub-divided into two
groups of parts which are interconnected only by friction disks 12. 12 see Fig. 5,
but as the separation of the carbon holders reverses the rotation of the arbor 8 the
spring is necessarily rewound in part. Thus in the act of pushing the carbon
holders apart the spring of the clock mechanism is automatically recoiled while the
gear wheel 52, loose upon its shaft, is allowed to slip between the disks, and since
said wheel now is stationary no disturbance or breaking of that portion of the train
which contains the escapement can occur. The spring can be so wound and
positioned with respect to the carbon holders that only the central portion of
said spring is actively employed and thus a more uniform rate of movement is
produced. A head 13 is attached exteriorly to the arbor for easy manipulation
and control of the carbon holders manually, if so desired. Moreover, upon the
bottom of the casing 2 are disposed two series coils 14. 15 both in the main feed
line and these are suitably insulated from the lamp structure. It will further be
seen that the lower carbon holder is likewise insulated at 16; hence the main feed
wire a may be attached at any convenient spot on the lamp structure, while the
wire 6 for the outgoing current is made fast to the negative carbon holder. The
upper end of the series coil 15 in the present instance is curved, which curve is
preferably concentric with the lower end of a soft iron plate 17 pendent from the
bottom of the clock casing 2 but these adjacent surfaces may be flat if desired:
thus when the current enters the coil the entire casing 21 is rocked being pulled
down by the action of the armature against the tension of the counterbalance
spring 18. This oscillation is sufficient to separate the carbons slightly or such a
distance as is necessary to establish an arc, while coincident with the rocking
movement of the casing and time piece, a coil 19 connected in shunt has lifted the
stop lever 21 and the train under the impetus of the coiled main spring is now free
to move at a predetermined rate of speed and will hereafter automatically maintain
a constant length of arc, or such an are as would be required for a perfectly constant
current and carbons which are homogeneous throughout.
But as these ideal conditions cannot continue since the current varies while the
density of the carbons differs from time to time, I have provided a controller 23 in
the shape of mechanism which is governed in its activity by the aid of a series
coil 14 before mentioned.
This controller is intended to serve to accelerate or retard the normal rate of the
time piece at certain moments when such feed-due to the then existing relations
which may continue between the current and the carbons, or both the current and
the carbons-shall exceed or lack the proper amount. However, in case of a
constant current and a variable potential, viz. when two or more lamps are burnt
in series, the series coil may be omitted and a shunt coil substituted. To carry out
this part of my invention I have affixed an armature 24 rigidly to a rocking lever
adapted to be controlled by springs 26. 26 or otherwise, while adjustable
stops 27. 27 prevent excessive movement in either direction. One end of the
spring 26' is made fast to a rod 28 revoluble in an upright 29 while a head 281
exteriorly of the box enables the rod to be rotated, thereby controlling the tension
of the springs 26. 261. In order to cause the action of the current which passes
through the series coil 14 to influence the oscillations of the balance wheel and
thereby directly serve to control said balance wheel and thus govern the time piece
in creating more or less feed movement to the carbon holders, I have furnished the
controller with a curved medium or element upon the armature 24, one end 30 of
said medium being flexible and is adapted to wipe against or contact with some
portion of the balance wheel. In the present instance this part of the wheel is in
the shape of a boss 31. The opposite end 32 is hooked inwardly in order that said
end may engage at proper occasions with the boss 31; the contact of this medium
at either end with the balance wheel may depend upon the strength of the current
or upon the density of the carbons singly, or upon both these conditions jointly..

page_text: Thus it will be understood that in case of rapid impairment of the carbons with
a normal current, in which event the arc would become too great, or should the
current be reduced suddenly, under either or both such conditions the feed must be
increased, when the springs serve to move the controller from the series coil with
the result that the hooked end 32 is thrust within the path of the boss on the
balance wheel. The oscillations of the latter are thus shortened and the rate of
the time piece is accelerated. Conversely under opposite conditions, or shortening
of the are, the controller is advanced over the series coil with the result that the
spring end 30 is caused to wipe the boss and thus create more or less friction, in
some instances merely causing a retardation, at other times a brief cessation in the
movement of the balance wheel. In this way the normal rate movement of the
clock train is retarded. In some instances to increase the stability of parts, lessen
their number and secure greater ease of adjustment, I employ the form of
controller 23' illustrated in Fig. 6. Here the weighted balance wheel is omitted
and in lieu thereof a balance lever 32 is provided carrying an escapement lever 322
which engages the escapement wheel 6. The armature 241 is hung on one
end of a friction arm 30 which end is upheld by a spring 26 while adjustable,
stops 27 prevent excessive movement in either direction. The opposite extremity of
said friction arin is bent and armed with a stud or pin which bears against one end
of the balance lever 23'. The pivot of the friction arm is at 30³. Thus it will be
seen that to increase or diminish the rate of the clock movement the balance
lever 321 may be made lighter or heavier, while this normal rate may be accelerated
or retarded by the current through the series coil 14', which will cause the pin to
bear with varying pressure against the balance lever and thus adjust the feed of
the carbons in accordance with the current or the quality of the carbons.
To provide universal adjustment for the various operating parts which comprise
the lamp structure as likewise to enable the position of the arc to be located in any
desired spot accurately, the following instrumentalities are grouped and co-operate.
Sliding movement of the support 20 in horizontal paths to and fro is produced by
the screw threaded rod 34 located in the base proper or standard 35. Vertical
rocking adjustment is accomplished by the aid of the lever arm 36, and adjusting
screw 37, the central point of oscillation being the pivot 38. Lateral or horizontal
oscillations are obtained about the shaft or column 39 which is made fast to the
support 20; this column is longitudinally splined at 40, see Fig. 4, and is equipped
with a worm gear 41 the relative position of which remains unchanged while a
worm 42 operated by a hand wheel 43 controls axial movement of the columus.
This spline and groove connection is to enable the raising or lowering of the lamp
structure in right line paths of travel that is to enable the gear 41 to slide upon
the column, while the operation of the worm 42 compels the lamp structure to
swing bodily with it. In raising the lamp structure the set screw 45 is relaxed
when the lamp and its various opening parts are caused to slide upward by turning
the lifting screw 46: the set screw 45 is again made fast and thereby prevents
accidental movements.
In the gperation of shutting off the current aud extinguishing the light, cessation
of the current through the series coil 15 releases the armature 17, when the
spring 18 lifts the casing 2¹ which rocks upon its arbor, causing by this slight
movement a feed action which again brings the carbons in contact or very nearly
Absence of current also renders the shunt coil 19 inoperative and the stop
lever 21 heretofore held from engagement with the escape wheel now drops by
gravity and the entire clock mechanism is brought to a standstill. At the same
time the series coil 14 which actuates the controller 23 is likewise rendered
inactive and the spring 26¹ pulls the post 25 against the adjusting pin 27¹. The
position of the boss 31 on the balance wheel is so arranged that the said wheel is
in readiness to start at any point in any portion of an oscillation; hence when
release of the stop lever occurs, positive movement of the balance wheel takes
place and the train is in motion.
In the drawings Fig. 1 the lamp structure and the various co-operating elements

page_text: are in their normal inactive positions prior to the admission of the current. In
Fig. 3 the casing containing the time piece is in a depressed position and the
balance wheel is brought within the controller to permit the latter to govern its
movement, during the admission of the current.
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 arc lamp the combination with carbon holders, and clock mechanism
adjusted for a predetermined rate, whereby the holders are caused to advance
towards each other, of a coil adapted to govern the clock mechanism to cause an
acceleration or retardation of its normal rate, whereby the arc may be continuously
maintained, substantially as and for purposes explained.
2nd. In an arc lamp the combination with carbon holders, clock mechanism
having a predetermined rate to advance said holders together, and an oscillating
frame adapted to rock at stated times, of a series coil, and a controller governed
by said coil, whereby the normal rate of the clock mechanism is accelerated or
retarded, substantially as stated.
3rd. The combination with two carbon holders, clock mechanism suitably
mounted and adjusted to a predetermined rate, a balance wheel, and two toothed
racks which carry said holders, of differential toothed gears operated by the clock
train to produce different feed travel in the carbon holders, a series coil, and
mechanism from said coil to the balance wheel, whereby the predetermined rate of
the clock mechanism is caused to vary, substantially as specified.
4th. In an electric arc lamp structure, two carbon holders, a series coil, a con-
troller governed by said coil, and a rocking frame, combined with clock mechanism
located in said frame, a weighted balance wheel therefor, and means to cause said
frame to swing, whereby the balance wheel and the controller are permitted to
engage at stated intervals, substantially as herein set forth.
5th. In an arc lamp, two carbon holders, a clock train to actuate the holders, a
balance wheel, a controller to engage the balance wheel, and a series coil which
governs the controller, combined with a second series coil adapted to bring the
controller and balance wheel together to enable them to co-operate, and a stop
lever operated by a shunt circuit to stop or start the mechanism, substantially as
stated.
6th. In combination with a suitable standard, and carbon holders movably.
attached, a rocking frame mounted therein, clock mechanism with a weighted
balance wheel in the frame, and a series coil adapted to rock said frame and
temporarily retract the carbons by the agency of the clock train upon admission of
the current through the series coil, substantially as described.
7th. In an arc lamp, the combination with the carbon holders, a time piece
adjusted to a predetermined rate of speed, and a balance wheel in said clock
provided with a boss, of a series coil, and a controller governed by the current
through the said coil, whereby said controller is caused to accelerate or retard
the movements of the balance wheel, substantially as set forth.
8th. In an electric arc lamp, a time piece adjusted to a predetermined rate of
speed, two carbon holders actuated by said time piece, and a weighted balance
wheel on said time piece, combined with a controller having a friction end and a
stop end respectively, to retard or accelerate said balance wheel, and a series coil
adapted to govern the controller with respect to the balance wheel, substantially
as specified.
9th. In an are lamp the combination with two carbon holders, an oscillating
frame adapted to rock at stated times, a series coil, and a controller governed by
said coil, of a clock train, and a weighted balance wheel, said clock train con-
prising two portions frictionally united, whereby the carbon holders may be
separated without operating the balance wheel of the train, substantially as
described.

page_text: 10th. In an arc lamp, the combination with two carbon holders, a time piece
adjusted to a predetermined rate of speed, and an escapement lever, of a series
coil, and a friction arm adapted to contact against the escapement lever, and
governed by the series coil, whereby the said arm controls the escapement lever
to retard the normal clock rate, substantially as set forth.
Dated this Fifteenth day of February 1896.
JOHN ALBERT SEAVERNS.