Improvements in Electric Are Lamps.
Year: 1895

page_text: Date of Application, 22nd Oct., 1895-Accepted, 11th Jan., 1896
Improvements in Electric Are Lamps.
I, THOMAS EDGAR ADAMS, of the City of Cleveland, in the County of Cuyahoga,
and State of Ohio, United States of America, Electrical Engineer, do hereby
declare the nature of my invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:-
My invention relates to an improvement in electric arc lamps the object of the
invention being to provide a simple and efficient means for switching the lamp into
and out of circuit and for automatically establishing the arc, and with these ends,
in view the invention consists in certain features of construction and combination
of parts as will be hereinafter described and pointed out in the claims.
In the accompanying drawings,
Figure 1 is a view partly in side elevation and partly in vertical section of one
construction of lamp embodying my invention, the parts being in the position they
assume when no current is passing through the lamp.
Figure 2 is an enlarged detached view of a portion of the regulating mechanism,
showing the relative position of its parts when no current is passing through the
lamp.
Figure 3 is a view similar to that of Figure 2, but showing the relative position
of the several parts when the lamp is operating normally in burning its carbons.
Figures 4 and 5 are detail views of the clutch.
Figures 6 and 7 are detail views of the contact I.
A represents an electro-magnet which is provided with a fine wire helix A' the
ends of which are electrically connected respectively to the positive and negative
terminals A A' of the lamp and hence the belix is in a constantly closed shunt
around the a10. B is a coarse wire magnet, one end of which is electrically con-
nected with the positive terminal A³ of the lamp, while its opposite end is connected
with the clamp C within which is adjustably secured the carbon contact D.
Clamp C as shown 18 made of two sections b b which are secured at one end to a
plate or support C' by means of screws a, a' and are insulated therefrom by mica
or vulca-beston washers or strips, while by means of a screw C' extending
through the outer and free ends of the clamp sections, the carbon contact D may
be readily adjusted or renewed.
E represents a plate or bracket which is constructed with a downwardly pro-
jecting flange e through which are inserted screws e¹ for fastening the plate to the
pole F of the electro-magnet. Plate or bracket E is provided with downwardly
projecting ears e between which is pivoted the armature lever G, the latter being
provided with steel bearing points of which engage within the countersunk
openings formed in the ears. A screw e extending through both ears serves
to draw them together and thereby adjust the play or end thrust of the steel
bearing points. To the long arm g of the armature lever is adjustably secured
the armature g' by means of screws 9 wbich pass through elongated slots g³.
Gis a yoke-piece the lower end of which is adapted to be adjusted by a set screw g³,
so as to regulate the width of the air-gap between the armature and yoke piece.
The short arm of the armature lever is formed with a hole H with which com-
municates a slot II formed between the arms 11. By means of a screw H³ the
diameter of the opening H may be enlarged or contracted as desired. Within
opening His secured an adjustable carbon contact I, which is insulated from the
armature-lever by means of a mica washer I'.

page_text: A metallic contact J is constructed with a split sleeve J¹ within which is placed'
the contact I Hence the contacts I and J are electrically connected with each
other, while they are both insulated from the armature lever.
K is a stationary contact fastened to but insulated from the plate or bracket E,
to which one end of a resistance coil or stack L is secured while the opposite end
of the resistance is connected in series with a portion only of the course wire helix
by means of the conductor 1' and conducting and connecting plate L².
A clutch-1od M is pivoted at its upper end to the short arm of the armature
lever, while its lower end has secured thereto the arm of a friction clutch M' which
is constructed as follows -N is a stationary clamping plate provided with ears n n
which are connected together by a rivet N'. A lever N³ 18 constiucted with
perforated cars or lugs through which pass the rivet N' and by means of which
the lever arm is journalled to the clutch.
O is a movable clamping plate or jaw and is constructed with a transverse groove
within which enters the rivet N' by means of which the movable jaw or plate is
retained against vertical displacement. A lateral movement is unpailed to jaw O
by the shoulder o on the lever arm N' engaging a seat o' formed on the inver side
of the jaw. Seat o' is rounded so as to enable the inovable jaw to accommodate
itself to any slight irregularities on the surface of the clutch blade, or to prevent
any binding action of the parts.
When no current is passing through the lamp the parts are in the position
illustrated in Figure 1, in which position the carbon contacts D I are in engage-
ment, and a good contact is formed and maintained between them by the action of
the armature lever and the weight of the amature and dash-rod piston attached
to its long arm. When in this position the carbon electrodes X X' are maintained
in a separated relation by means of the weight of the armature and dash-pot piston,
and a closed circuit of low resistance shunting the carbon is formed through the
coarse wire helix B, contacts D, I flexible conductor O, to the negative terminal A³
of the lamp.
Immediately on the passage of the current through the lamp, the coarse wire
helix will energize the magnet and serve to attract and draw upwardly the
armature and consequently separate the carbon contacts D I, and thereby interrupt
the cucuit through them with the result that an arc will be established between
them. But this arc will be maintained for an instant of time only, because by the
operation of raising the armature the carbon electrodes are brought into contact,
the circuit through which is of so much lower resistance than the circuit through
the coarse wire helix and are formed between the contacts D I, that the current
will be instantly diverted through the carbon electrodes X X', and the are between
the contacts D I will be extinguished and the coarse wire helix thereby open-
circuited. The carbons are brought into contact by the action of the weighted
armature lever which on being attracted and upwardly moved by the coarse wire
magnet attains sufficient momentum to cause it to move upwardly a distance
sufficient to bring the carbons into contact, and to a point above the position
assumed by the armature when the carbons are burning.
The carbons after having brought into contact in the manner described are
immediately separated again by the action of the weighted armature, with the
result that the circuit formed by them is interrupted and an arc is established
between them.
Immediately on the establishment of an arc between the carbon-electrodes, the
resistance of the arc so produced operates to divert such an amount of current
through the fine wire shunt helix, as to render the electro-magnet sufficiently
strong to attract the armature and govern and adjust its position to correspond to
the variations of resistance of the arc.
The number of ampère turns of which the fine wire helix is composed, bear such
a relation to the weight and adjustment of the armature, that when the arc is of
noitnal length these two antagonistic forces counterbalance one another, but since
the carbons are constantly being worn away by the action of the current and the

page_text: heat of the arc, and need constant adjustment, the regulating mechanism of the
lamp is always acting ever so slightly and delicately as may be necessary to
maintain an arc of normal length and a steady and uniform light. When the lamp
18 burning normally, current flows from the positive terminal A2 through the
conducting guide blade to the cross-head 2, carbon holder 3 through the
carbons X X', and from the negative carbon holder through the guide rod and
its tube 5 to the negative binding post As while a small percentage of the total
current flowing on the main line flows through the fine wire helix. As the arc
elongates by the burning away of the carbons, the resistance of the arc increases
which operates to cause more current to flow through the fine wire maguet and
strengthen it, and this operation continues until the armature has been raised to
such a position that its short aim will have so lowered the clutch-rod and clutch
connected therewith, as to cause the clutch to strike the lamp floor or clutch
tripping device 6 and release the clutch from its clutch-rod and allow the carbons
to feed toward one another and thus shorten the arc. The resistance of the arc
being decreased by its shortening, is followed by a weakening of the fine wile
belix, and a preponderating action of the weighted armature which again operates
or tends to operate to separate the carbons again. In this manner the carbons
are adjusted and fed until they have been consuined.
In the event the carbons should fail to feed by reason of the sticking or binding
of some part of the regulating mechanisin, the arc would continue to elongate, its
resistance would gradually increase and the shunt magnet would grow stronger
and stronger until it had raised the armature to such a height as to have closed
the contacts K and J, and thus established a shunt circuit around the are
comprising a portion of the coarse wne helix, the resistance coil or slack L in
series therewith, contacts K, J, and flexible conductor leading to the negative
terminal of the lamp. Ou the closing of this cut-out circuit the current which
had hitherto passed through the carbons will now be diverted through the cut-out
circuit around the arc and the latter will be immediately extinguished. This
safety cut-out will maintain the integrity of the main circuit and insure the
continued operation of such other lamps as may be included therein. In the event
the carbons of the lamp should drop into contact again, after the lamp has been
automatically cut-out as described, the circuit through the carbons would be of so
much lower resistance than that of the safety cut out that the coarse wire magnet
would be so weakened as to be unable to longer maintain the contacts K, J closed.
Therefore the amature would fall and separate the carbons, with the result that
the arc would again be established and would be regulated and the carbons fed in
the manner already set forth.
When the current ceases to pass through the lamp, due to the switching the
lamp out of the circuit or to a cessation of the curent in the lighting circuit, the
weighted amature will diop, and by reason of its gravity, will operate to bung
the carbon-contacts together with such force as to insure a perfectly good electrical
contact between them.
M2 is a cylindrical cylinder or protector made of glass-carthenware or any other
suitable refractory material This cylinder or shield has an open bottom and is
cut away on one side so as to form a slot m to enable it to be placed over the
contacts and when in position to be supported on the plate E. Protector M by
enclosing the contacts effectually prevents the arc from injuring any of the parts
of the lamp, and prevents the short-cncuiting of the current from the contacts.
I have not described in detail the construction and function of each one of the
several parts of the regulating mechanism of the lamp illustrated in the diawing,
because all of said features which are not herein claimed are fully shown, described
and claimed in my application filed even date herewith, and are illustrated in the
diawings of this Patent for the purpose of explaining the operation of my
improvement in clutches and cut out mechanism which form the subject-matter of
this Patent.

page_text: 1
7
Having now particularly described and ascertained the nature of my said inveu-
tion and in what manuer the same is to be performed, I declare that what I
claim is :-
1st. In an electic arc lamp the combination with a pair of carbons, a course
wire magnet, and a weighted ai mature constructed and at anged to maintain the
carbons sepainted when no current is passing through the lamp, and to bring the
carbons into contact by the momentum it acquies when current is sent through
the conise wire magnet, of renewable carbon-contacts for switching the main
magnet into and out of circuit, one of said contacts being mounted on the weighted
armature lever and the other being mounted on a stationary support, substantially
as set forth.
2nd. In an electric arc lamp, the combination with a coarse wire magnet and its
armature, of an adjustable clamp on the armature lever, and an adjustable clamp
on the lamp, and a pair of carbon contacts adjustably secured in said clamps, and
serving to switch the main magnet into and out of circuit, substantially as set
forth
3rd. In an electric arc lamp the combination with a coarse wire magnet and a
weighted armature for bringing the carbons into contact, of a pan of renewable
carbon contacts, one being cairied by the armature lever and the other being
stationary, the construction and arrangement of parts being such that the carbon
contacts are separated and an arc is formed between them by means of which the
integrity of the circuit including the coarse wire magnet is maintained until the
carbons of the lamp have been brought into contact, substantially as set forth.
4th. In an electric aic lamp the combination with a coarse wie magnet and a
'weighted armature lever for bringing the carbons into contact of a pair of cai bon-
contacts, one being carried by the weighted armature lever and the other being
stationary and a flexible conductor electrically connecting the armature lever and
negative terminal of the lamp, substantially as set forth.
2
5th. In an electic arc lamp the combination with the fine wire magnet and
weighted armature lever acting in opposition thereto, of a coarse wie helix, a
pair of carbon contacts the movable member being mounted on the armature lover,
a resistance included in series with a portion of the coarse wie helix and a
conductor electrically connecting the movable contact with the negative terminal
of the lamp, substantially as set forth.
6th. In an electric arc lamp the combination with a coarse wue-magnet and
weighted amature lever for maintaining the carbons normally separated and for
bringing the carbons into contact by the momentum of the weighted armature
lever when curient is sent through the lamp, of a fine wie magnet acting in
opposition to the weighted aimature lever for regulating the feed of the carbons,
and a pair of adjustable carbon contacts included with the coarse wire magnet in a
circuit around the arc, substantially as set forth.
7th. In an electric arc lamp the combination with an armature lever, one end of
which is constructed to form an adjustable clamp, of a detachable carbon secmed
in said clamp, and an insulating washer encucling the carbon, substantially as set
forth.
8th. In an electric arc lamp, the combination with a stationary contact and a
contact carried by and insulated from the armature lever, of a cut out cucuit
comprising a portion of the coarse wire helix and a resistance in series therewith,
substantially as set forth.
9th. In an electic arc lamp the combination with the carbon-contacts of a
protecting shield of refractory material encueling the carbon-contacts, substantially
28 set forth.
10th In an electric are lamp, a fiction clutch consisting in the combination of
a clamping plate or jaw provided with laterally projecting ears or side walls and
with a pivotal pin connecting the outer ends of said eais o sides, and a lever
pivotally mounted on said pivotal pin, of an adjustable clamping plate or shoe

page_text: constructed with an open slot for the reception of the pivotal pin, and provided
with a shouldered bearing with which engages a shoulder formed on the lever,
substantially as set forth
11th. The combination with the clamping plate and lever pivoted thereto, said
lever being provided with a shoulder located above its pivotal bearing, of a
clamping plate or shoe constructed and arranged to have a movement independent
of that of the lever, and provided with rounded seat against which bears the
shoulder on the lever, substantially as set forth.
Dated this 22nd day of October 1895.
HERBERT HADDAN & Co.,
18 Buckingham Street, Strand, London, W.C.,
Agents for Applicant.