Improvements in and relating to Electric Arc Lamps.
Year: 1899

page_text: Date of Application, 2nd May, 1899
Complete Specification Left, 29th Dec., 1899-Accepted, 3rd Feb., 1900
Improvements in and relating to Electric Arc Lamps.
I, ROGER UPTON, President of The Standard Thermometer and Electric Com-
pany, of Peabody, Massachusetts. United States of America, do hereby declare
the nature of this invention to be as follows:-
My invention has for its primary object the rectification, in electric arc
lamps, of certain deficiencies the existence whereof has hindered the use of this
type of lamp upon circuits bearing the alternating current, a use which, for
many reasons, would have grown rapidly in favour had it not been for the lack
of the improvements hereinafter disclosed.
Such is the nature of these improvements that, while chiefly important in
their contribution to the production of a successful lamp for alternating cur-
rents, their embodiment in electric are lamps generally is attended by a remark-
able increase in efficiency.
Briefly stated, the advantages afforded by the present improvements are, that
a more perfect control and regulation of the carbons is effected; almost perfect
noiselessness is secured: the initial cost of the lamp, and its weight, are reduced
by simplicity of design and the use of few parts: and in operating expenses an
even more evident reduction is effected by the provision of means for facilitat-
ing the trimming and cleaning, and for enabling the trimmer to determine
visually, and at a distance, the condition of the carbons; moreover, for the first
time, a lamp is provided which can without alteration or adjustment be used
alternatively upon circuits bearing either alternating or direct currents.
It is recognised generally that to adapt a lamp of this type for use with alter-
nating currents of relatively low frequency, a large amount of resistance or
impedance must be arranged in circuit, and it is recognized equally that it
would be desirable to confine this resistance or impedance within the limits of
a single coil, but a coil of sufficient dimensions has been found impracticablo
because subject to the evils attendant upon heating effects of the current.
The use of iron about the coil has increased its tendency to heat, and added
otherwise to its defects without increasing its efficiency to a compensating
degree, so that in practice it has been the custom to introduce an extra resist-
ance-coil into the circuit.
With such an arrangement, however, the initial influx of current into the
magnet solenoid exerts too rapidly its influence upon the core, ranks or jerks
the clutch-lever, and breaks the are before it is fairly formed, so that with a
repetition of these yanks or jerks, the carbons chatter violently and annoyingly
for a perceptible time before the arc is set.
According to one part of the present invention. I employ a regulating sole-
noid characterized by a separation from each other of its constituent coils. i.c.,
either the helices, or if desired the individual convolutions, in any convenient
manner, for example by the introduction of separating devices, in the contour,
number, and situation of which, considerable variation will be found permis-
sible; the said separation can, for example, be effected by the interposition of

page_text: asbestos or an equivalent heat-suppressing medium between the said helices o
convolutions.
By separating the coils, heating effects may be so obviated that the size of
the solenoid and its consequent resistance to the initial influx of current may
be increased far beyond that found practicable hitherto, and the initial mag
netic effect upon the core will be delayed and steadied as already noted.
Exterior ventilation of the solenoid may be, and preferably is, provided for
by isolation from adjacent mechanism so far as practicable.
In some instances a shelf of suitable contour, is carried by the central tube
or post in any suitable manner, as by an insulating collar, provided preferably
with means for adjusting it, the regulating solenoid being secured to the shelf
by a suitable clamp the contour of which may be varied as desired or found
suitable.
1
According to another part of my said invention, in order to enable the lamp
to work efficiently with alternating currents of different frequencies or of
different electromotive force, a choking coil or solenoid is employed having
several connected sections or layers of wire wound about a common core and the
connections whereof form suitable terminals, with either of which a conducting
wire in series with the regulating solenoid can be readily connected so that
either a single one of the said coils or layers or two or more of the same in
series can be included in the circuit, and thus more or less reactance or impe-
dance introduced into the same, according to whether the alternating current
is of low or high frequency or according to the electromotive force of the
current.
To obtain a greater range of adjustment, an auxiliary choking coil or sole-
noid is also provided, which can, at will, be included in the circuit in series with
or without one or more of the sections or layers of the multiple choking-coil or
solenoid.
For supporting the "reactance" or "impedance" solenoids and also the regu
lating solenoid, and at the same time insulating them from the metal parts of
the lamp-frame, a clamp-bracket is provided which is constructed with, for
example, three sockets to receive the solenoids respectively, such socket
having a clamping-plate and screw for securing the corresponding solenoid
therein. This clamp-bracket is made with a central slit spring boss which fits
upon the central tube or post of the lamp-frame and grips the same tightly
enough to ensure its retention on the said tube or post in any position in which
it may be secured thereon. The said solenoids are insulated from their sockets
by the intervention of asbestos or other suitable insulating material. If desired,
the said bracket can be insulated from the said central tube or post by means of
an insulating collar. Or, if desired. two or more brackets may be employed
each supporting one or or more solenoids,
To adapt the lamp for use alternatively with either alternating or direct cur-
rents, a circuit-controller, such, for example, as a six-pole double knife-switch
is employed, having opposite pairs of terminals to which are connected respec-
tively the alternating current and direct current leads, the latter having the
usual rheostat included in its circuit. The lamp-terminals are connected
respectively by suitable conductors to the middle terminals of the said circuit-
controller, that its to say, to the terminals to which the movable arms forming
the switch-lever are pivoted. With this arrangement, by a
the switch-lever, the lamp can be connected with either the direct current cir-
simple throw of
cuit or the alternating current circuit.
For the purpose of increasing the effect of the current in the coil of the
regulating solenoid upon its movable core, it is advantageous to provide the
said solenoid at its lower end with an annular or other suitably-shaped arma-
Lure which is preferably mounted on springs so as to prevent noise due to
vibration, the said springs being arranged so as to permit adjustment of the
said armature towards and away from the end of the solenoid.

page_text: The regulating or feed-lever in the improved lamp is pivoted to a clamp-
bracket which is secured upon the central tube in such a manner that it can
be easily adjusted thereon to set the said lever in the proper position. The
dash-pot for the said lever is also secured to the said central tube by means of
an adjustable clamp-bracket.
A vibration-absorbing device is provided in conjunction with the regulating
or feed lever, to take up the vibrations inseparable from the use of the alter-
nating current and thus obviate the necessity for the vibration-deadening
devices heretofore employed. The improved vibration-absorbing device com-
prises a spring interposed between the clutch-arm which is extended beyond
the clutch-rod for the purpose, and a support carried adjustably by the said
clutch-rod.
It has been found in practice that this device prevents effectually any joggling
down of the carbon in the clutch, so often resulting in burning out the sole
noid, when former types of these lamps are used in places subject to mechanical
jar, as for as for example on the posts to which the trolley wire of electric rail-
ways is attached.
The regulating or feeding clutch is preferably made of greater depth than
heretofore and while the lower portion of the central opening that receives the
carbon is made cylindrical as usual, its upper portion is made taper or conica!
and a suitable shoulder is provided at the junction of the conical and cylindrical
parts. The said taper or conical portion facilitates the dropping of the carbon
into the opening should it it any time be pushed upward out of the same by a
slight explosion in the lamp or otherwise, while the aforesaid shoulder serves
as a stop for the metal socket or carbon-holder so that the spent carbon can be
readily withdrawn therefrom.
To protect the mechanism from the heat and to deaden noises due to vibration,
a thick disc of asbestos is secured by means of a clamp-bracket upon the central
tube of the lamp-frame in such a position that it will form a heat-resisting
diaphragm in the lamp cover or casing between the are and the mechanism.
The lamp cover is suspended from the top of the lamp-frame by means of a
bayonet-joint, the slots of which are formed in the cover and are so shaped that.
when the cover has been pushed up into engagement with the pins in the top of
the lamp-frame and then turned through a small angle, it can descend through
a short distance so that the said pins will engage with hooks at the outer end
of the slots and thus prevent disconnection of the cover from the lamp-frame
without first raising the said cover to release the pins from the said hooks.
Accidental disengagement of the cover from the frame is thus obviated. Suit-
able shields are provided for closing the bayonet-slots in the cover when the
latter is in place and thus preventing the entrance of rain and dust. These
shields also serve as clamping devices for securing the cover in place.
The sliding contact or rider" which is preferably employed for establishing
electrical connection between the central tube and the carbon therein, consists
of a series or group of curved springs which are secured at their lower ends to
a metal socket for holding the carbon, and have their upper ends free and
arranged so as to bear against a screw-nut fitted upon a screw-threaded rod
extending upward from the top of the said socket. By turning this nut so as
to move it in one or the other direction upon the said screw-rod, the pressure
which the said springs will exert against the inner surface of the central tube
can be increased or diminished as may be desired. The said springs are pre-
ferably made in pairs, by stamping, with a suitable central boss whereby they
can be threaded upon the said screw-rod.
The metal socket for holding the carbon preferably consists of a cylindrical
tube of resilient material fitting loosely within the central tube or post and split
throughout a considerable portion of its length to form jaws which grasp the
head of the carbon with sufficient force to prevent displacement accidentally by
shock or otherwise. The split may be on one or both sides, and is preferably

page_text: enlarged at one or more points, to augment the resiliency of the jaws, the lower
aperture serving the additional function of affording the operator a better grip
or hold, either with his fingers, or with a toggle or the like if the carbon and
rider be heated.
"
The said rider or sliding contact, may be varied in form without departing
from the nature of the said invention. For example, two or more springs can
be employed secured by suitable fastenings to the body of the rider and extended
beyond the walls thereof to contact yieldingly with the walls of the tube or
post, the two springs being bent back upon themselves in position to contact
with each other, thus deriving mutual support, with enhanced resiliency and
conductivity.
I'
As one means of protecting these devices from injury, the walls of the rider
may be extended above the devices and slutted or otherwise apertured, in permit
access of the devices to the walls of the post.
The lower carbon supporting or "trimming" mechanism comprises as essen-
tials only a head, hangers, a swinging seat or latch, and a receptacle for the
carbon. Any suitable means may be used to connect the said latch or seat with
the hangers, such as nuts engaging screw-threads on the lower ends of the
hangers. One form of latch has an aperture at one end to permit the passage
of one hanger, about which the latch can be rotated without the necessity for
entire removal, a slot, preferably curved, serving at the other end of the latch
to permit the entrance laterally of the other hanger as the latch swings around
into the closed position, a similar medial slot being provided, preferably. to
receive the foot of the receptacle, which. similarly to the corresponding nul, is
of suitable contour to co-operate with the enlarged and counter-sunk inner ends
of the said slots.
Another important feature of the said invention is the provision of means to
indicate visually to the operator, standing at a distance, the condition of the
carbon. For example a small incandescent lamp is placed in any convenient
position in the lamp-frame adjacent to an aperture in the cover, through which
the light of the lamp will be visible.
A conductor taps the circuit at a convenient point and another conductor leads
to a point adjacent to the carbon, where is arranged a circuit-closer. comprising
a stationary, but preferably adjustable member, adapted to be engaged by a
co-operating member movable with and controlled by the carbon, the latter
member consisting most conveniently of the rider itself.
In this instance, the other member of the circuit-closer is carried by a flange
or shoulder on the crown at the upper end of the globe immediately enclosing
the are, through the medium of a projection insulated from the said flange or
shoulder and having an adjustable collar which bears the latter member of the
circuit-closer and presents it towards and in position to be engaged by the rider.
Upon such engagement, a circuit, in shunt with the arc, is completed.
This indicating device may be set, (by adjustment of the said collar in this
instance.) to operate when the carhens have yet to burn, say, fifteen hours, and
if the lamps are installed by the hundred in some store the trimmer need only
walk across the front of the store and glance hack at the lamps, to determine
by the glow of the incandescent lamps, which of the are lamps are in need of
attention.
D. YOUNG & Co.,
11 & 12. Southampton Buildings, Chancery Lane, W.C..
Agents for the Applicant.

page_text: Improvements in and relating to Electric Arc Lamps.
I, ROGER UProx, President of The Standard Thermometer and Electric Com-
pany, of Peabody, 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:-
My invention has for its primary object the rectification, in electric are
lamps, of certain deficiencies the existence of which has hindered the use of this
type of lamp in alternating current circuits; but while my improvements are
chiefly important as applied to lamps for alternating currents, they may
be embodied in electric are lamps generally, such embodiment being attended
by a great increase of efficiency.
The chief improvements of this invention relate to the construction of the
regulating and impedance solenoids and to the means for supporting the same?
to an armature for the regulating coil; to a switch for switching the lamp into
the alternating or the direct current circuit as may be required; to the con-
struction of the carbon regulating or feed mechanism; to the method of sus-
pending and securing the lamp cover: to the upper carbon holder, and
contact devices in connection therewith: to the devices for supporting the lower
carbon to the provision of a glow lamp in a shunt from the main circuit for
the purpose of indicating visually to the trimmer at a distance when the carbons
required attention; and to various details as hereinafter described.
Briefly stated the advantages afforded by my improvements are, more perfect
control and regulation of the carbons; almost perfect noiselessness; the reduc-
tion of the initial cost of the lamp and its weight, by the simplicity of the
design, and by the use of few parts: and the attainment of a very evident
reduction in operating expenses; moreover a lamp is provided which can with-
out alteration or adjustment be used alternatively upon either alternating or
direct current circuits.
In the accompanying drawings I have illustrated a lamp embodying my
improvements, and having in this instance three solenoids, iz.. the regulating
solenoid, a multiple impedance or choking solenoid so constructed and arranged
that any one or more of its coils or layers can be placed in series with the regu-
lating solenoid, and an auxiliary impedance solenoid which is provided for in-
creasing the range of the resistance or impedance that can be introduced into
the lamp circuit.
Referring to the accompanying drawings which illustrate my invention:
Figure is a sectional elevation of the lamp.
Figure 2 is a vertical section on the liner, r, Figure 1. looking from the left of
said figure, parts of the lamp being shown in side elevation.
Figure is a diagrammatic plan of the solenoids.
Figure 4 is a vertical section on a larger scale through the holder of the
upper carbon and adjacent parts.
Figure 5 is a similar view illustrating a modification.
Figure 6 is an enlarged vertical section of the carbon clutch.
Figure 7 is a sectional elevation also on a larger scale of the dash pot con-
nected to the feed regulating lever.
Figure S is a plan of the latch for supporting the lower carbon.
Figure 9 is a side view of a portion of the cover illustrating the bayonet
joint and shield.
Figure 10 is a plan of the switch and connections for switching the lamp into
the direct or alternating current circuits as required.

page_text: Figures 11 and 12 are plans drawn to an enlarged scale of solenoids herein-
after described.
Figure 18 is a side elevation illustrating a modified method of clamping the
solenoid to the frame.
Like letters of reference denote corresponding parts in the several figures.
A is a central tube which carries the various parts of the lamp, and serves
for conducting the current to the upper carbon which slides within said inhe;
Bis the regulating solenoid: C the multiple impedunce solenoid; and D) the
auxiliary resistance or impedance solenoid.
The solenoids which use are characterised by separation from each other of
the constituent coils or layers i.c., either the helices or if desired the individual
convolutions, in any convenient manner, for example, by the introduction of
separating rods or equivalent devices such as Figure 11. in the contour,
number and situation of which, considerable variation will be found permissible,
or by the interposition of asbestos or an equivalent non-conductor of heat
between the heliers or convolutions of the solenoid, as indicated in Figure 12.
By separating the coils in this manner, heating effects are obviated so that
the size of the solenoid and its consequent resistance to the initial influx of
current may be increased far beyond that found practicable hitherto, besides
which the initial magnetic effect on the core is delayed and steadied.
Exterior ventilation of the solenoid is provided for by isolation from adjacent
mechanism as far as practicable
For supporting the aforesaid solenoids and at the same time for insulating them
from the metal parts of the lamp frame, a clamp bracket. E is provided which
is constructed with three sockets to receive the solenoids, each socket having a
clamping plate e and a screw e for securing the corresponding solenoid therein.
This clamp bracket is made with a central slit spring boss. Figure 3, which
fits upon the central tube & and grips the same tightly enough to ensure its
retention thereon in any position in which it may be set. The solenoids are
insulated from their sockets hy the intervention of asbestos or other suitable
insulating material, and in some instances the elamp bracket is insulated from
the central tube A. by means of an insulating collar. If desired the solenoids
may be individually supported by independent brackets instead of by a single
bracket.
For increasing the effect of the current upon the movable core of the regu-
Inting solenoid B, it is advantageous to provide this solenoid at its lower end
with an annular or other suitably shaped armature which is preferably carried
by springs so as to prevent noise due to vibration, said springs being clamped
between the solenoid and the corresponding socket of the clamp bracket E.
This arrangement admits of the armature being adjusted towards and away
from the end of the solenoid.
In order that the lamp may work efficiently with alternating currents of
different frequencies OL of different electromotive force, the multiple
impedance solenoid C. is formed, as previously stated. of several con-
mected sections or layers of wire wound about a common core and the
connections whereof form terminals with any of which a conductor in series
with the regulating solenoid can be readily connected so that either a single
one of the said coils or layers or two or more of the same in series can be included
in the circuit, and thus more or less impedance may be introduced into the same,
according to whether the alternating current is of low or high frequency or
according to the electromotive force of the current. I sometimes make this
solenoid as follows, that is to say, al about the centre of each winding or layer.
1 form a long loop which is bent and brought up to the top of the coil forming
a series of terminals e....,, to any one of which the conductor leading
from said coil can be connected and in this way, a length of wire equal to one.
two or more layers of the coil can be used according to the amount of resistance

page_text: or impedance required. By this construction 1 avoid having to take leads from
each end of the coil and am still able to vary the resistance by amounts repre-
sented by one layer or multiples thereof. The lower carbon-supporting or trim-
ming mechanism comprises a head F secured to the tube A by screwing or
otherwise, hangers F, F, carried by said head, a swinging seat or latch and
a socket or receptacle G in which the lower carbon is held by a screw g. The
latch or seat is secured in position by nuts f,f, engaging screw threads on
the lower ends of the hangers. It is perforated at f to permit the passage of
one hanger, about which the latch, can be turned without the necessity for
entire removal, a slot at the other end of the latch serving to permit the
entrance laterally of the other hanger as the latch swings around into the closed
position, and a similar medial slot to receive the foot of the receptacle G.
The inner ends of the slots f,, are enlarged and countersunk as indicated in
Figure S to fit the coned ends of the corresponding nut f and foot of the recep-
tacle G. A spring is introduced between the latch at one end and its nut to
afford flexibility in the support. T is an annular reflector carried by the
hangers F, F.
To trim the lamp, the nuts ff are slacked back, and the latch swung from
under the socket (i whereupon the latter comes out into the hand bringing with
it the lower carbon and the inner globe P which rests snugly but freely at its
lower end on a seat washer within the rim g' of the socket G.
At its upper
end the globe l' is seated in a similar manner against a gasket or washer p
within a recess in the head F. This washer is held in place by a ring or fer-
rule which also serves to support the gas check made of lava or other heat
resisting and insulating material, and forming with the ring and head Fa
gas ch. aber . The globe P has no metal parts and can therefore be washed
in hyd-fluoric acid if need be so that no time will be lost in cleaning it. The
spent per carbon can be withdrawn by hand and a new one inserted and the
pari
The
cond
then all replaced. thus completing the operation of trimming.
urrent enters the lamp by the binding post H and passes through the
or to the solenoid is and thence by the conductor to the central
stationary tube A from which it is collected by certain sliding contact devices
hereinafter described, connected to the upper movable carbon, which is enclosed
by the said tube. The current returns by the socket G which carries the lower
carbon, the latch F2 and the hangers FF to a binding post f³, thence by the
conductor to the connector y of the impedance solenoid C, and thence by the
conductor to the stationary part or jaw of the switch J. The movable part
of this switch consists of an arm fixed on a spindle which turns in a bear-
ing in the top A of the lamp frame and is actuated by a handle. The
arm is in electrical connection with the binding post H by a conductor /'.
The connector y can be moved to any one of the terminals to and in this
way the amount of resistance or impedance may be varied as desired. Further
the auxiliary coil D can be brought into the circuit by moving the connector y¹
to the terminal of the coil D'and the connector y² to one of the terminals e
to e, said connector y having a conductor d which passes to the other terminal
of the coil D. By leaving the connector y in the position indicated in the
drawing, and transferring the connector y to the terminal d the coil C is cut
out of the circuit altogether, so that a very great range of variation of resistance
or impedance is possible with this arrangement.
The passage of the current is accompanied by the energization of the sole-
noid B which then attracts its core B and drawing the same down thereby
through the medium of the pivoted feed lever K. clutch rod 1. attached to said
lever, and clutch M. raises the upper carbon and strikes the arc. the uniformity
of which is maintained thereafter by the response of the core to the magnetic
influence of the current acting through the solenoid B. I prefer that the
core B' be cylindrical and composed of soft iron with a filling of laminated iron,

page_text: and find it desirable to interpose a spring between it and the regulating
feed lever K to take up vibrations. is a nut for adjusting the core, and 64
denotes removable weights for balancing the feed lever.
The said feed lever K is pivoted to a clamp bracket K' which is secured upon
the central tube A in such a manner that it can be easily adjusted up and down
thereon to set the said lever in its proper position. The dash pot N for the said
lever is also secured to the said central tube by means of an adjustable clamp
bracket N. This dash pot comprises a plunger a, Figure 7. having annular air
packing grooves a', and a cylinder 2, both secured on the bracket N', and a
cylinder, open at the bottom and closed at the top and suspended by a link n'
from the feed lever K. The cylinder a slides between the plunger a and the
cylinder and at its upper end are small openings a which are covered by a
at annular valve which is retained in place by a cylindrical cover. This
device allows the carbon to fall quickly but retards the upward movement of
the carbon.
A vibration-absorbing device is preferably provided in conjunction with the
regulating or feed lever, to take up the vibrations inseparable from the use of
the alternating current, thus obviating the necessity for the vibration-deadening
devices heretofore employed. The said vibration-absorbing device comprises a
spring interposed between an extension of the clutch arm m and a support m²
carried by the clutch rod L and adjustable thereon. It has been found in prac-
tice that this device prevents effectually any joggling down of the carbon in the
cluteh, so often resulting in burning out of the solenoid, when former types
of these lamps are used in places subject to mechanical jar, as for example, on
the posts to which the trolley wire of electric railways is attached.
The regulating feeding clutch M which rests at times in a recess M₁ of the
head is preferably made of greater depth than heretofore and while the lower
portion of the central opening that receives the carbon is made cylindrical as
usunl, its upper portion m. Figure 6, is minde taper or conical to facilitate the
dropping of the carbon into the opening should it at any time be pushed upward
out of the same by a slight explosion in the lamp or otherwise. The said conical
part also serves as a stop for the metal socket or holder of the upper carbon so
If desired, a shoulder
that the spent carbon can be readily withdrawn therefrom.
may be formed in the clutch to act as a stop for the said socket.
To protect the meebanism from the heat and to deaden noises due to vibra-
tion, a thick disc of asbestos O is secured by means of a clamp bracket 0 upon
the central tube A in such a position that it will form a heat resisting din-|
phragm in the lamp cover or casing between the are and the mechanism.
The sliding contact or rider which is preferably employed for establishing
electrical connection between the central tube A, and the carbon therein, con-
sists of a series or group of curved springs r, Figure 4, which are secured at
their lower ends to the metal socket which holds the carbon. The said
springs have their upper ends free and arranged so as to bear against a screw
nut fitted upon a screw-threaded rol, extending upwards from the top of
the said socket. By turning this nut so as to move it in one or the other
direction upon the screw rod P, the pressure which the springs will exert
against the inner surface of the central tube A can be increased or diminished
as may be desired. The said springs are preferably made in pairs, by stamping
with a suitable centrul opening and are threaded upon the screw rod, and
secured by a nut 4.
The metal socket 71, preferably consists of a cylindrical tube of resilient
material fitting loosely within the central tube A and split at throughout
considerable portion of its length to form jaws which grasp the head of the
carbon with sufficient force to prevent displacement accidentally by shock
otherwise. This split may be on one or both sides, and is preferably enlarged
at one or more points as at 6, to augment the resiliency of the jaws, the lower
aperture serving the additional function of affording the operator a better grij

page_text: either with his fingers, or with a pencil or the like if the carbon and rider be
hot.
This rider or sliding contact, may be varied in form, for example two or more
springs Figure 5, may be employed secured by screws or other suitable
fastenings to the body of the rider and extended beyond the walls thereof to make
contact yieldingly with the tube A. the two springs being bent back at upon
themselves in position to make contact with each other, thus deriving mutual
support with enhanced resiliency and conductivity. As one means of protecting
these springs from injury, the walls of the rider may be extended beyond the
springs as shown, and slotted or otherwise apertured at 10 to permit of the springs
making contact with the tube A.
The lamp cover Q is suspended from the top of the lamp frame by means
of a bayonet joint, the slots g, Figure 9, of which are formed in the cover and
so shaped that, when the cover has been pushed up into engagement with the
pins and then turned through a small angle, it can descend through a short
distance so that the said pins will engage with hooks at the inner ends of the
slots and thus prevent disconnection of the cover from the lamp frame without
first raising the said cover to release the pins g from the said hooks. Accidental
disengagement of the cover from the frame is thus obviated. Suitable shields g³
are provided for covering the bayonet slots in the cover when the latter is in
place, thus preventing the entrance of rain and dust. These shields also serve
as clamping devices for securing the cover in place.
In order to indicate visually to the operator standing at a distance, the con-
dition of the carbons, I provide a small incandescent lamp s. adapted to be
included in a shunt to the are lamp circuit, and placed in any convenient posi
tion within the cover adjacent to an aperture therein through which the light
of the incandescent lamp will be visible. One terminal of the said lamp is
connected by a conductor to the binding post and the other terminal is con-
nected by a conductors to a binding post carried by the head F but insu-
lated therefrom, where is arranged a circuit closer, comprising a stationary, but
preferably adjustable, finger electrically connected to the binding post and
adapted to make contact with a co-operating member movable with, and con-
trolled by, the carbon, the latter member consisting most conveniently of the
metal socket or carbon holder . When the carben falls so far that the socket r
comes in contact with the finger the incandescent lamp circuit in shunt with
the are is completed, and the filament of the said lamp then glows.
This indicating device may be set, (by adjustment of the socket ) to operate
when the carbons have yet to burn say 15 hours, and if the lamps are installed
in large numbers, the trimmer need only walk past the installation and glance
up at the same, to determine by the glow of the incandescent lamps, which of
the arc lamps are in need of attention.
To adapt the lamp for use alternatively with other alternating or direct cur-
rents, a circuit controller, comprising a six-pole double knife switch is employed
having opposite pairs of terminals 1,, and . Figure 10, to which are con-
nected respectively the alternating current and the direct current leads, the
latter having the usual rheostat included in its circuit. The lamp terminals
are connected respectively by suitable conductors to the middle terminals P.P
of the said circuit controller, that is to say, to the terminals to which the movable
arms forming the switch lever are pivoted. With this arrangement, by a
single throw of the switch lever, the lamp can be connected with either the
direct current circuit or the alternating current circuit. The rheostat shown
consists of a bare coil of wire supported on the lamp top and insulated there-
from. The direct current enters at one end of the coil and is taken off at any
intermediate point by a clamp which is connected to one of the terminals
by a conductor to. The clamp can be attached to the rheostat at any point inter-
mediate of its ends.
In Figure 13, I have shown a modified method of supporting the regulating

page_text: coil. In this instance it is carried by a plate ir secured to the central tube A,
and perforated to promote ventilation. The coil is secured on the plate by
screw clamps, asbestos or other insulating cushioning material and wear
plates being if desired interposed between the coil and the clamps. The
cushioning material is arranged to cover as little as possible of the coil so as to
promote ventilation.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, 1 declare that what
I claim is
1. A solenoid having its coils arranged co-axially and separated by rods or
equivalent devices, substantially as, and for the purpose, described.
2.The use of a multiple choking coil or solenoid comprising several sections
of wire wound about a common core and connected in such a manner that their
points of junction form terminals with any of which a conductor in series with
the regulating solenoid can be connected so as to increase or diminish the resist-
ance or impedance in the lump-circuit, substantially as herein before described.
8. A choking coil in which the leads are brought out from the various wind-
ings in the middle of the coil, substantially as, and for the purpose, specified.
4. The employment of an auxiliary choking coil or solenoid adapted to be
included in the circuit in series with the regulating solenoid and with one or
more of the sections or layers of the multiple choking coil or solenoid, substan-
tially as herein before described and for the purposes specified.
The clamp-bracket constructed with sockets to receive the solenoids and
with clamping devices for securing the solenoids therein, and with a slit spring
boss to engage with the central Tube of the lump-frame, substantially as, and
for the purposes, above specified.
6. The combination, with the reguinting solenoid, of an armature mounted
at the lower end of the said solenoid, and adjustable relatively thereto, sub-
stantially as, and for the purpose, above specified.
7. The armature claimed in the preceding claiming clause, carried by spring
supports, substantially as, and for the purpose, specified.
S. The regulating or feed lever pivoted to a clamp-bracket which is secured to
and adjustable on the central tube of the lamp-frame, as, and for the purpose,
above specified.
9. The dash-pot for the regulating or feed-lever secured to the central tube
by an adjustable clamp-bracket, as, and for the purpose, above specified.
10. The combination, with the regulating or feed lover, and the clutch-arm,
of a spring interposed between the said clutch-arm and a support secured to
and adjustable on the clutch-rod, substantially as, and for the purpose, above
specified.
11. The clutch having the lower part of its opening for the carbon of cylin-
drical form and the upper part thereof taper or conical with or without a shoulder
at the junction of the taper and cylindrical parts, as, and for the purposes,
above specified.
12. The combination, with the lamp-cover suspended from the lamp-frame by
a bayonet-joint, of shields which serve for covering the slots of the bayonet-
joint and also as clamps for securing the cover in place, as above set forth.
18. A sliding contact-member or rider comprising a series or group of curved
springs fixed at one end and adjustable at their other end by means of a screw-
nut on a central screw-threaded rod, substantially as herein before described and
for the purposes specified.
14. The carbon-holder provided with my improved sliding contact or rider.
substantially as described with reference to Figure 4 of the drawings.
15. A sliding contact-member or rider comprising springs secured to the inner
walls of a hollow cylinder and tending normally to present current-collecting
surfaces beyond the outer walls thereof, the said springs being bent back upon

page_text: themselves from the said collecting surfaces, and in contact with each other.
and serving mutually to augment their resiliency and co-operating to conduct
the current, substantially as described with reference to Figure 5 of the drawings.
16. A device for supporting the lower carbon, comprising a head, hangers
extended downwardly therefrom, and a foot-latch or seat connected to and sus-
tained by the said hangers and capable of being turned about one of the said
hangers, as, and for the purposes, above specified.
17. The combination, with a lamp of the class herein before referred to, of a
six-pole double knife-switch having its middle pair of poles, to which the movable
armis of the switch are pivoted, connected respectively with the lamp-terminals,
its pair of poles at one end adapted to receive the leads of an alternating current
circuit, and its other pair of end poles adapted to receive the leads of a direct
current circuit, substantially as, and for the purposes, above specified.
18. The employment of a disc of asbestos secured by means of a clamp-
bracket upon the central tube of the lamp-frame and forming a heat-resisting
diaphragm between the are and the mechanism, as above set forth.
19. The employment of an incandescent lamp arranged in the cover or casing
of an arc lamp adjacent to an aperture therein and adapted to be suitably con-
nected up in a shunt to the lamp-circuit as, and for the purpose, above specified.
Dated this 29th day of December 1899.
D. YOUNG & Co..
11 & 12, Southampton Buildings, London, W.C.,.
Agents for the Applicant.