Improvements in and relating to Electric Arc Lamps.
Year: 1898

page_text: Date of Application, 10th May, 1898-Accepted, 11th June, 1898
COMPLETE SPECIFICATION,
Improvements in and relating to Electric Arc Lamps.
We, FREDERICK AUGUSTUS GILBERT, of Brookline, County of Norfolk, State of
Massachusetts, United States of America, and EMIL OCTAVIUS LUNDIN, of Beach-
mont, County of Suffolk, Massachusetts aforesaid, Manufacturers, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following state-
ment:-
This invention has for its object the production of an enclosed are lamp of
improved construction, whereby among other features the trimming is greatly
facilitated, means being provided for holding the upper carbon in place while
removing the inner globe, so that the operator has both hands free. The feed
controlling clutch and the contact for the upper carbon are of novel and highly
effective construction, and the cap or cover for the inner globe is provided with a
novel valve through which the upper carbon can pass without binding when in
use.
The armature of the solenoid is mounted on a tubular member surrounding the
upper carbon, the upper end of said member having a piston to enter a centrally
supported dash pot at the top of the lamp, thereby greatly simplifying the con-
struction of the parts, the feed controlling clutch being mounted on the lower end
of the tubular member.
We have provided novel and effective means for automatically cutting the resis-
tance coil out of circuit when the lamp is started, the coil being in circuit only
when the lamp is not burning, or when the upper carbon is burnt out, and the
resistance coil is so located as to greatly economise space.
It has been found in practice that in the ordinary enclosed, series arc lamp, if
the carbon burns out the voltage of the arc will run up to 90 or 100, burning out
the globe and lower carbon holder, but in our improved lamp the voltage of the
arc will not be increased under such circumstances, so that danger of burning out
the globe or lower carbon holder is decreased to a minimum.
By the construction hereinafter described, the upper carbon will, when burned
out, be released from the controlling clutch, so that the ends of the carbons will
come together, and the current will then pass therethrough and through the
series coil to the line, without damage to the parts of the lamp.
Should the upper carbon by any chance stick when the lamp is burning the
safety cut out will be operated automatically to cut the lamp out of circuit."
The general construction of the lamp and the various novel features embody-
ing our invention will be, hereinafter fully described in the specification, and
particularly pointed out in the claims.
Fig. 1 represents in elevation an arc lamp embodying our invention, the outer
globe and the lamp case being shown in section, the lamp being shown as in use
or when burning.
Fig. 2 is a partial vertical sectional view of the armature and coils, with the
controlling clutch for the upper carbon in elevation, the clutch being in un-
clutched position.

page_text: Fig. 3 is an enlarged longitudinal sectional view of the contact member for
the upper carbon.
Fig. 4 is a transverse sectional view thereof' on the line -, Fig. 3;
Fig. 5 is an enlarged top or plan view of the valve or closure for the inner
globe;
.
Fig. 6 is a diametral sectional view thereof on the line, Fig. 5;
Fig. 7 is a detail in elevation and on an enlarged scale, of the removable globe
holder and support for the lower carbon;
Fig. 8 is a transverse sectional view thereof on the line y-y, Fig. 7.
Fig. 9 is a partial diagrammatic view of the coils and circuits;
Fig. 10 is a lower end view of the armature and tube' in which the upper car-
bon travels;
Fig. 11' is an enlarged view in front elevation of the lower part of the lamp,
with the spider drawn down;
Fig. 12 is a top or plan view of the cross bar shown in Fig. 11, with its depend-
ing hub, and
Fig. 13 is a perspective view of the seat for the inner globe holder.
Referring to Figs. 1. and 2, the lamp frame comprises an open, upper body
portion A, preferably made as a metal casting having a cylindrical base A', the
sides having openings therein for the free circulation of air; to aid in maintain-
ing the adjacent portions of the lamp cool.
The base A', has, see Fig. 2, an upturned hub A* and a central aperture through
which is passed a longitudinally movable metal tube B for a purpose to be
described, the cage like body A receiving therein the usual series wound and
shunt coils C and C₁ respectively, the core upon which the coils are wound resting
on the base A¹ and being positioned by the hub A*.
A top A² having an inner hub A³, see Fig. 2, closes the body portion, said, hub
being shouldered at 2 to support a spring S which assists the solenoid in lifting
the tubular clutch actuator B, the lower end of the hub being recessed to permit
full movement of the armature C*.
A washer 3 of insulating material is interposed between the base A', and a
ring A, held in place by suitable insulated screws 4, said ring having attached
thereto depending members A5, preferably tubular, into which fit telescopically
rods A6, see Fig. 1, secured to a spider A7.
a
The lower ends of the tubes A are rigidly attached to a cross-bar a: having
central opening a¹, Fig. 12, and cut away at a between the two lateral ears a" at
the front of the bar, two similar ears being extended laterally from the back of
the cross bar, and beneath the latter depends a tubular hub a concentric with the
opening a¹, said hub being adapted to pass through the threaded part A70 of
the spider.
The spider is held in place by a suitable nut A8, Fig. 1, locked onto the pro-
jecting lower end of the hub a in usual manner, and the shade or outer globe G*
is supported normally in the position shown in Fig. 1 by a socket A held in
place by the threaded part A70 of the spider.
The seat a for the inner globe holder is shown separately in Fig. 13, it being
substantially an open, ring like member having ears at which are so disposed as
to register with the ears a³ of the cross bar, the seat being held in place on the
cross bar by insulated screws 5, 6, while washers 7 of insulating material are
interposed between the cross bar and the seat at.
The seat a is provided with diametrically located clamping screws 8 which are
engaged by oppositely turned hooks d, see Figs. 7 and 8, laterally extended from
a casting D adapted to rest on the seat a, said casting having a central tubular
portion through which is extended the lower carbon L, a socket d² receiving
the lower end of the inner globe G.
A clamping screw d³ extended through the tubular portion of the globe sup-
port holds the lower carbon firmly in position.
It will be seen by viewing Fig. 8 that when the screws 8 are loosened, a partial

page_text: turn of the globe support D will withdraw the hooks d from engagement with the
said retaining screws, so that the globe support and globe can be removed bodily
from the lamp.
When replacing the globe support, the reverse operation is carried out and
when the hooked ears dare in position, the retaining screws 8 are tightened.
This serves to centre the lower carbon as well as to provide a readily operable
detachable connection for the globe support.
Referring to Fig. 2, the clutch actuator is shown as a tube B extended longi-
tudinally through the open body A of the lamp, said tube contacting with the
base A¹, although passing freely therethrough, the armature C. being rigidly
secured to the tube by a clamp screw c², see Fig. 10.
The armature is sleeve like in form having a conical upper end and shouldered
at c', the armature being longitudinally split, as shown in Fig. 10, so that it may
be tightly compressed upon the clutch actuator B by tightening the screw c*.
The shoulder c¹ serves to limit the downward movement of the armature by
coming in contact with the upturned hub A of the base.
The operation of the armature and its series, wound coil C is as usual in other
lamps, the current acting, through the solenoid, to raise the armature and with it
the clutch actuator, the shunt coil depressing the latter.
The lower end of the tube B is extended below the base A into a longitudin-
ally slotted depending guide f, secured to the underside of the base A' and having
attached to its lower end a tube fi in alignment with the clutch actuator B.
This: tube has rigidly secured thereto, a contact device for the upper carbon, said
device comprising a disc g, see Fig. 3, having an annular flange g on its under
face, the disc supporting a cylindrical-casing g² having screwed into it a base g³,
suitable screws 10 holding the casing and disc y together.
As clearly shown in Fig. 3, the base is curved upward from its periphery to a
central boss surrounding an aperture through which the upper carbon L'
freely passes, the top of the base thus presenting an annular seat for a series of
radially disposed independently movable members g*.
Each of said members has a straight outer edge, an upturned lug g at its upper
end, and a convexed inner edge, increased in width at 7, the lower corner of each
contact member resting on the annular seat formed by the base, adjacent the
casing g
The shape of the contact members is such that they tend to drop inwards by
gravity, towards the longitudinal axis of their supporting member, the flange gl
serving to limit such inward movement when the upper carbon is withdrawn by
engaging the lugs g6.
When the carbon is inserted the contact members g* are pushed outward
sufficiently to permit its passage between them, the centre of gravity of each
member causing it to rest lightly yet surely against the carbon, to form a good
contact therewith, said contact members and their support being of course made
of metal.
These gravity contact members always ensure a constant contact between the
upper carbon and the circuit, the current passing to the support and contact
members, as will be described and by their use sparking or arcing is prevented
when the clutch wheels leave the carbon...
A ring & secured to the casing has extended laterally therefrom a slotted car !
through which is extended loosely an arm 2 pivottally connected at its lower end
with the inner globe cover or cap h, said arm being notched at its inner side at
12 and having a finger h by which it and the cap h* may be lifted.
When the cap is in place on the globe G, see full lines, Fig. 1, the upper notch
engages a cross pin 13 in the ear h¹, a pin 14 preventing accidental withdrawal
of the arm from the ear.
The downwardly flanged cap * fits over the upper edge of the globe G, while
the central portion of the cap is depressed at 4, Fig. 6, and provided with an
upturned hub exteriorly threaded at its upper end at hº.

page_text: A centrally apertured disc h has on its underside a flange threaded at 78 and
outwardly bent at h between the disc and the threaded portion, so that when the
latter is screwed on past the thread h of the hub the disc will be held onto the cap,
while free to move laterally a limited amount.
The upper carbon passes freely though closely through the disc h', which acts
as a valve to close the upper end of the globe, but should the carbon be slightly
out of alignment, or the globe slanted, the lateral play of the valve prevents the
carbon from binding.
Now when the trimmer wishes to trim the lamp, he lifts the arm 2 by means
of the finger h³ until the lower notch 12 engages the detent pin 13, holding the
arm in dotted line position Fig. 1, and at the same time the cap is inclined and
raised, the inclination of the cap from the horizontal causing the upper carbon to
be caught and lifted with the cap.
The upper carbon will be held up thereby as long as the arm 2 is retained lifted
by the detent, so that the trimmer has both hands free to effect the proper trim-
ming of the lamp.
When the trimming is finished a slight lift on the finger ³ will release the arm,
so that it and the cap will return to normal, operative position, at the same time
releasing the upper carbon."
In trimming the globe G is removed while the cap is lifted, after which the
cap is lowered, as far as it will go, and the upper carbon is pushed up through it
and then pulled out, so that a new one can be inserted.
The cap is then lifted as before, holding the upper carbon stationary while the
globe is replaced.
A long carbon can be readily inserted by putting the lower end down through
the slotted hub as, then turning it up vertically to be passed up through the con-
tact and feed controlling devices, the opening a² in the cross bar and the open
seat a permitting the turning up of the carbon.
The feed controlling clutch for the upper carbon comprises two preferably
grooved metal wheels b, loosely journaled in elongated, substantially horizontal
slots b formed in bifurcated carriers 62, pivotted below the wheel journals at b³ to
arms on a ring 6 sliding on the tube f which is longitudinally slotted at f² to
permit the peripheries of the oppositely mounted wheels to engage the carbon
within the tube.
The carriers are outwardly bent to form arms which are pivottally connected by
links 65 with lateral projections on a ring 66 rigidly secured to the lower end of
the tubular actuator B, and brake shoes 67 adapted to bear at times on the
peripheries of the wheels are pivottally mounted in outward extensions 68 of the
carriers.
The lateral projections of the ring be extend through the longitudinal slots of
the guide f, as shown in Figs. 1 and 2, permitting movement of the ring up and
down as the actuator B rises and falls with the armature C* of the series wound
coil C.
Now, owing to the relative position of the wheels, brake shoes, and fulcra b³
of the carriers, when the actuator is raised the links rock the carriers and bring
the brake shoes b to bear against the wheels, forcing them against the carbon and
stopping their rotation so that the carbon is lifted."
When the amount of current passing through the shunt coil C increases, the
armature and clutch actuator B will descend, and the carbon is lowered, still held
by the clutch, until the ring b is stopped by an adjustable collar 610 on the tube f¹,
and further descent of the ring 66 will throw off the brake shoes, releasing the
carbon.
By adjusting the collar 610 the separation of the carbons is mechanically effected
to vary the length of the arc.
The current enters the lamp by the line wire 1, Figs. 1 and 9, which is electri-
cally connected with the metallic body A, the current passing thence to the tube B

page_text: and to the carbon by several paths, principally however, by the contact members g*,
the contact device as a whole being diagrammatically represented in Fig. 9 at C³.
We have herein shown the lamp as adapted for use with constant direct currents,
the windings of the coils being arranged for that purpose, but by altering the
windings and necessary connections the lamp may be used for other systems.
The current passes from one carbon to the other, forming the arc when the
lamp is burning, and from the lower carbon L by insulated wire to one end of
the coil C, through the latter and back to line at l¹.
One end of the shunt coil C' is connected electrically at with the body A,
and its other end with the line wire at c, Fig. 9, so that if the are becomes too
long more current will pass through the shunt, weakening the effect of the series
coil C on the armature, which with the clutch actuator B will descend, so that
the controlling clutch will permit the proper feed of the upper carbon to properly
shorten the arc and thereby maintain the proper length thereof.
The actuator B carries a contact c adapted at times to engage a fixed contact c
mounted on and insulated from the body A, said fixed contact being connected
by a wire with a resistance coil R', the latter being in circuit with the line
wire by wire, Fig. 9.
When the current is turned off the cut-out circuit 13, 14, is closed, and the car-
bons are in contact, but when the current is turned on to start the lamp the cut out
resistance will cause enough current to pass through the series coil C to raise
the armature and separate the carbons, such movement of the armature then
breaking the cut out circuit at c, e, throwing out the resistance R¹.
Sometimes the upper carbon might stick long enough for the cut out circuit to
be closed, cutting out the lamp, and then the carbon might be released, and as
soon as the carbons come in contact the circuit will be completed through them and
the cut-out circuit opened.
It will be seen that we dispense altogether with a holder proper for the upper
carbon, it being controlled entirely as to its feed by the clutch device described.
The resistance coil R' is wound upon the exterior of the body B, insulated
therefrom by a sheet m of mica, preferably, the windings being separated by air
spaces as shown, and another resistance coil R is similarly mounted on the body A
above the cut-out resistance R¹.
The resistance R is connected at its upper end at 18 with the wire l*, and at its
lower end to the wire 4, so that the more resistance is inserted the greater will
be the current in the series coil C, and the greater the separation of the carbons
and length of the arc.
By decreasing the resistance the current in the series coil will be reduced and
the arc shortened, so that by varying the resistance the length of arc is regulated.
The resistance is varied by a sliding contact cl2 mounted on a guide c¹³ insu-
lated from the body A, and connected at c4 with wire *, a set screw c¹, Fig. 1,
holding the sliding contact in adjusted position, the contact moving over and
contacting with the windings of the resistance coil R.
Should the upper carbon burn out sufficiently to fall out of the controlling clutch
the end of the carbon will come together, the current then passing directly through
the carbon and series coil to line, without any tendency to burn out adjacent parts.
The cut-cut circuit operates automatically to cut the lamp out of circuit if the
upper carbon should stick, for the tube B will gradually descend until the ter-
minals e, c, of the cut-out circuit contact, thus throwing the lamp out of the line
circuit.
Upon suitable standards 35, see Fig. 2, on the lamp body A is supported a
cylinder D3 closed at its upper end, and receiving therein a piston D fast on the
upper end of the actuator B, said cylinder and piston forming a centrally located
direct acting dash-pot, to regulate the movement of the upper carbon and prevent
sudden jumps thereof which might be caused by the operation of the feed control-
ling mechanism.
The upper part of the lamp is enclosed in a light, ornamental sheet metal pro-

page_text: tective casing M, open at top and bottom to permit free circulation of air there-
through to aid in keeping the lamp cool.
At its lower end the casing is flared at M to extend over the top of the outer
globe G, and is provided with air inlet perforations m³, outlets m³ being provided
at the upper end of the casing.
t
A cover M2 encloses the top of the body A and the adjacent parts, protecting
them from dust and injury.
The lamp hanger H may be of usual construction, with leaders H' for the line
wires and l¹.
Our invention is not restricted to the precise construction and arrangement as
herein shown, as the same may be varied without departing from the spirit and
scope of our invention.
Having now particularly described and ascertained the nature of our said in-
vention, and in what manner the same is to be performed, we declare that what we
claim is:-
1. In an arc lamp, a feed controlling clutch including rotatable members to
directly engage the carbon, rocking carriers for said members, brakes mounted on
the carriers to prevent rotation of and press said members against the carbon,
and an actuator to operate the carriers and control the brakes, to thereby raise and
lower the clutch bodily, substantially as described.
2. In an are lamp, a feed controlling clutch including rotatable members
adapted to directly engage the carbon, rocking carriers for said members, brakes
mounted on the carriers, and an actuator to control the operation of the brakes
and thereby throw the clutch into and out of operation and also to raise and lower
the same bodily, combined with an adjustable stop to effect release of the carbon at
a predetermined point, substantially as described.
3. In an are lamp, a feed controlling clutch comprising rotatable contact mem-
bers, rocking carriers therefor, brakes mounted on said carriers, to press the contact
members against the carbon and prevent their rotation, a tubular actuator in which
the upper carbon is freely movable, and connections between said actuator and
carriers, to operate the latter and thereby regulate the feed of the carbon, sub-
stantially as described.
4. In an arc lamp, the lamp body, a depending guide having a longitudinally
slotted, tubular extension through which the upper carbon is loosely extended,
combined with a controlling clutch for said carbon, comprising rotatable contact
members, rocking carriers therefor, a support for said carriers, adapted to slide
on the tubular extension, brakes on the carriers to act upon and force the contact
members against the carbon, a clutch actuator, and connections between it and the
carriers, to operate, substantially as described.
5. In an are lamp, a globe having a removable cover, through which the carbon
passes, and means to lift the cover and retain it lifted from the globe for trimming,
the cover when lifted engaging and holding the upper carbon stationary, substan-
tially as described.
6. In an arc lamp, a globe having a removable cover through which the carbon
is normally adapted to freely pass, a lifting arm to which said cover is pivottally
jointed, and a detent to retain said arm and cover lifted, the cover when lifted
inclining to the horizontal and engaging the upper carbon to prevent its downward
movement, substantially as described.
7. In an arc lamp, a globe cover having a central upturned hub exteriorly
threaded at its upper end, disc having an opening in which the carbon snugly
fits, and a downturned, outwardly bent flange on said disc, threaded to engage
the hub of the cover, the bent portion of the flange permitting lateral movement
of the disc after separation of the said threaded portions, substantially as described.
8. In an are lamp, a globe cover having a central upturned hub, a cooperating
disc having an opening in which the carbon snugly fits, and means to retain the

page_text: disc on the cover while permitting free lateral movement about the hub, substan-
tially as described.
9. In an arc lamp, a globe cover having a central opening through which the
carbon loosely passes, a cooperating disc apertured to snugly receive the carbon,
and a detachable connection between the cover and dise, permitting relative lateral
movement thereof without separation, substantially as described.
10. In an arc lamp, a controlling clutch for and to directly engage the carbon,
a longitudinally movable tubular actuator therefor, in which the carbon is freely
movable, a cut out circuit in which said actuator is included, and a circuit con-
troller one member of which is fixed and the other mounted on the actuator, move-
ment of the actuator to separate the carbons in starting the lamp breaking the
cut-out circuit, substantially as described.
11. In an arc lamp, an open cylindrical body, series wound and shunt coils
enclosed therein, and a resistance coil wound upon the exterior of said body and
insulated therefrom, whereby said resistance coil is supported independently of
the series and shunt coils, substantially as described.
12. In an arc lamp, a cylindrical body, series wound and shunt coils enclosed
therein, a resistance coil wound upon the exterior of said body and in shunt with
the series coil, and a sliding regulator to adjust the resistance, substantially as
described.
13. A contact device for electric lamp carbons, comprising a supporting member,
and a plurality of independent gravity contact members mounted to rock about
their lower ends, said lower ends resting on the bottom of the supporting member,
the upper sections of said members having enlargements on their inner faces adapted
to rest against the surface of the carbon, substantially as described,
14. A contact device for electric lamp carbons, comprising a tubular support
having a centrally apertured base, a plurality of independently movable gravity
contact members, mounted at their lower ends on said base and radially disposed
around the aperture therein, adapted to rock on their lower ends and move their
upper portions into contact with the carbon, and a stop to engage the upper ends
of said contact members and limit their inward movement, substantially as
described.
15. A contact device for electric lamp carbons, comprising a tubular support
having a centrally apertured base, and a series of radially disposed gravity contact
members mounted on said base and normally moved by gravity towards the longi-
tudinal axis of the support, the lower ends of said members resting on the base
adjacent the tubular support, substantially as described.
16. In an arc lamp, a main body portion, depending arms connected at their
lower ends, clamp screws on said connection, and a lower carbon holder provided
with oppositely turned, hooked ears to engage and be held in place by said clamp
screws, substantially as described.
17. In an arc lamp, a detachable lower carbon holder having a globe socket and
oppositely turned hooked ears, combined with a support having clamp screws to
be engaged by said ears, to retain the holder in place, substantially as described.
18. In an arc lamp, the main body portion, depending arms connected at their
lower ends by a cross bar, a hub thereon longitudinally slotted at one side, and a
lower carbon holder detachably mounted on the cross bar, substantially as
described.