IMPROVEMENTS IN ELECTRIC ARC LAMPS
Year: 1887

page_text: Date of Application, 29th Nov., 1887
Specification Accepted, 20th Jan., 1888
We, CLARENCE BINGHAM NOBLE, Chemist, and ROLAND DARIUS NOBLE, Attorney-
at-law, both of 12 Cheshire Street, Cleveland, Ohio, in the United States of America,
do hereby declare the nature of this invention for IMPROVEMENTS IN ELECTRIC ARC
LAMPS and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement :—
This invention consists in providing improved means for automatically throwing
the current from one set of carbons to another, when the former has been nearly or
quite consumed.
It also consists in furnishing an improved cut-out, and covers other details which
will be fully described in the specification and more particularly pointed out in the
claims.
In the accompanying drawings which illustrate our invention, Fig. 1. is a plan
view, and figs. 2. and 3. are respectively side and front elevations of our improved
lamp.
Figs. 4. and 5. show respectively front and side elevations of the movable joint
for actuating the carbons and operating the cut-out as will be described later on.
Fig. 6. is a detail view of one of the clutches and attachments, and fig. 7. is a
perspective view of the moving parts of the lamp.
Referring to the drawings by letter, Z. is the frame of the lamp and X and X¹ are
two sets of carbons forming part thereof.
A. and B. represent the usual thick and fine wire magnets respectively which act
differentially on a common core c¹.
Pivoted to the core and to a standard G. is a bar L. to which, between its pivots,
is attached a horizontal bar K, extending at right angles beneath the said bar L.
The ends of the bar are located beneath ring clutches d. and d' on the carbon-holders T
and T. The clutches are supported on the ends of hooked links P and P' which are
suspended from the O shaped formations on the lever h, which latter is pivoted to an
extension E of the standard G. The lever h. is normally tilted, so that one end, say
that which supports the clutch d, is lower than the other, being under tension from
a spring Yas shown.
The construction is such that one end of the bar K rests normally directly under
the clutch d while the other end is considerably below the clutch d². As a con-
sequence, only the rod T will be acted on when the bar K is lifted to establish
the arc.
It will be understood that the hooked links P support the ring.clutch in. a

page_text: horizontal position, and that a tilting of the clutch to grasp the carbon-holder
takes place when the bar strikes against the clutch. The same action has no effect
upon the other clutch d¹ because it is held up out of the way of the moving bar K
by means of the hooked links P¹ as shown in the figures.
The lever is connected with the movable core 6 of magnet D. This magnet D.
is wound with both fine and coarse wire, the fine wire being in the same shunt
around the arc with magnet B, and the coarse wire forming a part of the main
circuit.
The core b carries a projection 6¹ which plays between two pairs of contacts a¹ a¹¹
and a and o. The contact a is the terminal of the coarse wire coil on magnet D.
These contacts are formed of screws set into the insulating piece R, the different
wires being connected under their heads, as shown.
Referring to fig. 3, the main current enters the lamp at + and, after passing around
magnet A, branches at A¹ one branch 1. going to contact a" and the other 2. to the
coarse coil of magnet D. Which course the current takes depends on the position
of the strip with reference to the contacts, as will now be explained.
The normal position of the core b is down. The current in passing through the
lamp energizes magnet A, lifts its core and accordingly the bar K. Bar K tilts
the clutch d, which grips the carbon-holder and causes it to rise and establish
the arc.
As the carbons are consumed and the resistance becomes greater, more of the
current is shunted into magnet B, which operates on the core in the usual way and
lowers the bar K, allowing the rod to feed.
The course of the current is now as follows: from + through magnet A, out at A¹
and along branch 1. to contact a through strip b¹ to contact a¹ to upper carbon, to
lower carbon and to
When the arc is established the movement of bar K is not long enough to
impinge against the ring d--and so rod T and the X carbons only are separated.
When, however, the carbons are nearly consumed, the resistance increases abnor-
mally and the current in the shunt becomes stronger until magnet D becomes
sufficiently energized to lift its core and lift the strip 61 from contacts a¹ and a".
The full current then passes through the shunt wire, drawing core b up until strip b
makes contact with a and o. When this contact is made the main current then passes
over branch wire 2, through coarse coil on magnet D, contact a to strip 6' contact o
to the carbons X' and thence to
The heavy current now passing through magnet D holds the strip b¹ against the
contacts a and o.
The lifting of core 6 also causes the tilting of lever to a horizontal position, so
that ring clutch d' is brought within the movement of bar K, and as becomes
horizontal at the same time core 6 is elevated, the ring d' will be lowered upon the
bar K and be tilted to grip the carbon-holder, while the ring d will be lifted away
from the bar K.
The X carbons will now be consumed and fed in the same manner that the X carbons
were.
I
The main core c¹ is slotted, and a block J, shown in enlarged detail in figs. 4. and 5
is inserted into the slot and hung on a pin c which passes laterally through the core
and projects through the side thereof where it carries the adjustable screw e¹¹. The
block J is also slotted to allow the pin c¹¹ to slide within it, and it has an enlarged
base which extends out beyond the core to rest on the head of magnet B, as will be
set forth.
The bar L is pivoted to this block. The screw e¹¹ moves in the end of the pin c¹
and is adjustable over the spring-armature F of a magnet C which is secured to the
lamp frame.
The armature is secured to the insulating platform Y and has a piece of iron e
secured to its lower face, and is further provided with contact m which engages with
contact n on the head of magnet C, the latter contact being one of the terminals o
said magnet. .....

page_text: The terminals are in a branch circuit around the lamp from + to as shown in
figs. 2. and 3.
When the second set of carbons X' are burned out the resistance becomes excessive
and the magnet B draws the core down until the block J rests on top of the spool,
then the core continues to settle and the pin c¹¹ to move in the slot of J until the
screw e carried thereby forces the spring F down so that contact is made between m
and n.
The lamp is thus cut-out or short-circuited, and so long as the current passes
through magnet C the armature F will be held down.
The magnet D does not act to shift the lever h until the resistance of the X carbons
becomes excessive, owing to the complete or nearly complete exhaustion of the
carbons or of one of them. Under other conditions the spring Y₁ counter-balances
the pull of the said magnet.
The core c¹ may be supported on a spring S, shown in fig. 3, which can be placed
in the hollow core of the magnet B, so that when the carbons are normally feeding,
the weight of the said core will not cause the screw ell to bear down upon the
armature F to cut out the lamp, that is, the weight of the core c¹ is counterbalanced
by a suitably placed spring.
During the consumption of the first set of carbons the carbons of the second set
are in contact, the upper carbon being supported upon the lower, and thus the arc
establishing and feeding magnets are relieved of its weight. Similarly, while the
second set is being consumed the unused stub of the upper carbon of the X set is
resting on the lower carbon. In each instance, the clutch of the set not in use is
raised out of the path of the bar K.
It is evident that the contacts a¹ and all may be dispensed with, and that the
branch 1 may be run directly from A¹ to the carbon-holder T. It is true that in
this case there would be a circuit through the first set of carbons or what remained
of them, after the second set began to burn, but the resistance of such circuit would
be so great as practically to cut out the first set.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that what
we claim, is:
1. The hereindescribed mechanism for automatically switching the current from one
set of carbons to the other, consisting of the magnet D carrying a coil of fine wire
which is located in a shunt around the arc, and also a coil of coarse wire which is
adapted to form a part of the main circuit, the core of said magnet being movable,
connected with the tilting lever and carrying contact piece 61, in combination with
two pair of contacts, so arranged that when the piece b¹ bridges one pair the main
current shunts the magnet D, and when it bridges the other pair the main current
passes through the said magnet, as set forth.
2. In an electric lamp in which two sets of carbons are operated successively, the
combination with a tilting lever carrying at each end a clutch for operating to feed
each set of carbons, of a bar K for making operative successively the clutches when
they are thrust within its reach by the tilting lever, the motions of the lever being
controlled by the consumption of a set of carbons, as specified.
3. In an electric lamp, a slotted core for the main and shunt magnets, a slotted
block sliding within the slot in the core, a pin passing through the core and the slot
in said block, an adjustable screw carried by said pin and a pair of contacts adapted
to be brought together by the movement of said screw, the said contacts completing
a circuit to cut out the lamp, substantially as described.
Dated this 14th day of November 1887