Year: 1886

page_text: I, JOHN HENRY HOLMES, of No. 67 Westgate Road, Newcastle-on-Tyne in the
County of Northumberland, Electrical Engineer, do hereby declare the nature of
this invention to be as follows:-
This invention has for object improvements in arc lamps, and relates to means
for feeding the carbon, and for striking the arc.
I will describe the invention as applied to a lamp in which the carbons are set
vertically the one over the other, and in which the upper carbon only receives the
feed motion. It may, however, be applied to focussing lamps, and to lamps in
which the carbons are inclined or in a horizontal plane.
The upper movable carbon is supported by a rod which is, by preference,
cylindrical. This rod is carried in fixed bearings through which it can slide. It
is, however, prevented from dropping through them under the influence of gravity,
by a pair of brake or slipper blocks, which are held against it on either side by
bent flat springs attached to a frame or connected bars. This frame is pivotted or
hinged to the upper bearing or some other suitable support in such a manner as to
constitute a kind of parallel motion with one of the sides fixed. When the feed
takes place, there is imparted to the opposite side a reciprocating swinging or
vibrating movement by an electro-magnet in a manner described below. When
the frame is moved the bent springs suffer a change of form. One becomes
straightened, and its effective length thereby increased, while the other bends to
a sharper curvature under its natural elasticity, and its effective length is thereby
decreased. At the same time the pressure of the flattened spring upon the corre-
sponding brake block is augmented, and that of the bent spring lessened. The
result is that the pressure or grip of one block is increased and that of the other
lessened, with the effect that the former carries the carbon rod with it, while the
other slides over it, the two acting as friction pawls alternately gripping and
releasing the rod. On the back stroke the block, which before slipped backwards,
now drives the rod forward, while that which before effected the feed now slides
idly back.
The vibration necessary for actuating the carbon feeding device described above
may be very simply obtained in the same manner as in electric bells, and to this
end I employ an electro-magnet or solenoid the wire on which may form a shunt
circuit past the arc. An iron armature forming part of or attached to the vibrating

page_text: frame is drawn forward when sufficient current is passing through the magnet to
overcome the adjustable pull of an opposing spring.
In combination with the electro-magnet and its armature there is a make and
break apparatus so arranged that as long as the current through the coils of the
magnet is strong enough to cause the pull of the latter to overcome the opposing
pull of the spring the frame is kept vibrating to and fro. As long as the vibration
continues the upper carbon is slowly pushed downwards so as to decrease the
length of arc and this goes on until, owing to the difference of potential between
the carbons being lessened, the shunt current is no longer powerful enough to
cause the magnet to attract its armature and the motion ceases. As the carbons
are consumed the arc increases in length the difference of potential becomes greater
and the armature is again attracted by its magnet, thus feeding the carbons
together as required.
The vibratory motion of the frame may be obtained in other ways than by
means of a make and break apparatus; for instance, a small electric motor may be
arranged with its circuit as a shunt to the arc and may be adjusted so that when
the current through it exceeds the normal amount it will be set in motion and
continue in motion until, through its action, the arc has been again restored to its
proper length. This motor is arranged so that its rotary motion is by some
suitable mechanism such as a crank and connecting rods, converted into a
reciprocating motion for causing the feeding device to bring the carbons together.
It is not necessary that the electro-magnet described should have its circuit
arranged as a shunt to the arc, as it can be made to operate in a similar manner
to that described when its circuit forms part of the main circuit and the make and
break apparatus is a shunt to its coils. When thus arranged a decrease in the
main current owing to the length and resistance of the arc increasing allows the
armature to recede from the magnet and to break the shunt circuit round it,
the current in the magnet then increases and the armature vibrates to and fro.
causing the feeding device to bring the carbons nearer together.
To strike the are a solenoid, forming part of the main circuit, is arranged
vertically in a line with the upper carbon and has the bottom of the central hole
in its bobbin closed so that it forms a receptacle for mercury in which an iron core
forming part of the lower carbon holder, floats. On the passage of a current
through the solenoid the core is sucked downwards, thus striking the arc.
Tire too rapid movement of the core is prevented by forming its lower part as a
piston fitting loosely in the bobbin thus allowing the mercury to leak past it
slowly in the manner of a dash-pot. In addition to its other uses the mercury
acts as a very efficient metallic connection between one end of the solenoid and
the carbon holder. To retain the mercury in its receptacle in the event of the
lamp being overturned, a flexible diaphragm is arranged having its outer edge
secured to the upper flange of the bobbin and its centre to the iron core.
diaphragm closes in the top of the bobbin and acts as a guide to the lower carbon
holder without however materially affecting the free up and down movement of
the core in its solenoid.
This

page_text: I, JOHN HENRY HOLMES of No. 67 Westgate Road, Newcastle-on-Tyne, in the
County of Northumberland, Electrical Engineer, do hereby declare the nature of
this invention and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement :-
This invention has for object improvements in arc lamps, and relates to means
for feeding the carbon.
I will describe the invention as applied to a lamp in which the carbons are set
vertically the one over the other, and in which the upper carbon only receives the
feed motion. It may, however, be applied to focussing lamps, and to lamps in
which the carbons are inclined or in a horizontal plane.
The upper movable carbon is supported by a rod which is, by preference,
cylindrical. This rod is carried in fixed bearings through which it can slide.
It is, however, prevented from dropping through them under the influence of
gravity, by a pair of brake or slipper blocks, which are held against it on either
side by bent flat springs attached to a frame or connected bars. This frame is
pivotted or hinged to the upper bearing or some other suitable support in such
a manner as to constitute a kind of parallel motion with one of the sides fixed.
When the feed takes place, there is imparted to the opposite side a reciprocating
swinging or vibrating movement by an electro-magnet in a manner described
below. When the frame is moved the bent springs suffer a change of form. One
becomes straightened, and its effective length is thereby increased, while the other
bends to a sharper curvature under its natural elasticity, and its effective length is
th by decreased. At the same time the pressure of the flattened spring upon
the corresponding brake block is augmented, and that of the bent spring lessened.
The result is that the pressure or grip of one block is increased and that of the
other lessened, with the effect that the former carries the carbon rod with it, while
the other slides over it, the two acting as friction pawls alternately gripping and
releasing the rod. On the back stroke. the block, which before slipped backwards,
now drives the rod forward, while that which before effected the feed now slides
idly back. The vibration necessary for actuating the carbon feeding device
described above may be very simply obtained in the same manner as in electric
bells, and to this end I employ an electro-magnet or solenoid the wire on which
may form a shunt circuit past the arc. An iron armature forming part of or
attached to the vibrating frame is drawn forward when sufficient current is passing
through the magnet to overcome the adjustable pull of an opposing spring.
In combination with the electro-magnet and its armature there is a make and
break apparatus so arranged that as long as the current through the coils of the
magnet is strong enough to cause the pull. of the latter to overcome the opposing
pull of the spring the frame is kept vibrating to and fro. As long as the vibration
continues the upper carbon is slowly pushed downwards so as to decrease the
length of arc and this goes on until, owing to the difference of potential between
the carbons being lessened, the shunt current is no longer powerful enough to
cause the magnet to attract its armature and the motion ceases. As the carbons are,

page_text: consumed the arc increases in length the difference of potential becomes greater
and the armature is again attracted by its magnet, thus feeding the carbons
together as required.
The vibratory motion of the frame may be obtained in other ways than by
means of a make and break apparatus, for instance, a small electric motor may be
arranged with its circuit as a shunt to the arc and may be adjusted so that when
the current through it exceeds the normal amount it will be set in motion and
continue in motion until, through its action, the arc has been again restored to its
proper length. This motor is arranged so that its rotary motion is by some
suitable mechanism such as a crank and connecting rods, converted into a recipro-
cating motion for causing the feeding device to bring the carbons together. It is
not necessary that the electro-magnet described should have its circuit arranged as
a shunt to the arc, as it can be made to operate in a similar manner to that
described when its circuit forms part of the main circuit and the make and break
apparatus is a shunt to its coils. When thus arranged a decrease in the main
current owing to the length and resistance of the arc increasing allows the arma-
ture to recede from the magnet and to break the shunt circuit round it, the current
in the magnet then increases and the armature vibrates to and fro causing the
feeding device to bring the carbons nearer together.
In the annexed sheet of drawings there is shown so much of an arc lamp as is
necessary to a clear understanding of my invention.
Fig. 1 is an elevation with the cover removed and part of the electro-magnet
removed for the sake of clearness. Fig. 2 is an elevation at right angles to Fig. 1,
with the cover in section, but with the lower part of the lamp removed. Fig. 3
is a plan.
The upper carbon A is carried by a rod B which slides in bearings in the framing.
Against the rod there bear two slipper blocks C, D, each of which has a bent
spring For G pressing against its back with sufficient force to prevent the rod B
slipping down between them. The points of these springs take into nicks or
cavities on the backs of the slipper blocks, or they may be pivotted. thereto.
Each spring is pivotted or fixed at its other extremity to the frame, and is also
connected to a swinging or vibrating frame H H. This frame carries an arma-
ture I situated in front of the poles of the electro magnet E E. This armature is
subject, when the lamp is in action, to the attraction of the magnet on the one
side, and to the pull of the adjustable spring J on the other side. The frame H H
also carries a contact piece K which makes contact with the screw L; and a stop M,
which limits its travel.
The electromagnet E E is arranged as a shunt around the arc. The current
proceeds from the + terminal of the battery to the contact screw L, thence to the
contact piece K and through the coils of the magnet to the
-
terminal.
The operation of the lamp is as follows:-As the carbons waste the length of
. the arc increases, and consequently there is an augmentation of current in the
magnet E E. When the length of the arc exceeds the amount for which the lamp
is adjusted, the armature I is moved towards the poles of the magnet, carrying
with it the frame H H. By this motion the spring G is straightened (or approxi-
mately so) and its end pressed more strongly on the slipper block D. The spring F
is simultaneously allowed to bend under the action of its elasticity, but at the
same time its pressure on the block C decreases. The effect of these motions is
that the rod B is moved downwards by the slipper block D, while the block C
slides over it. But the movement of the frame H breaks the circuit, and conse-
quently the magnet loses its power. The frame then swings back under the
influence of the spring J, with a reverse effect to that just described on the
springs F and G. The spring F is now straightened and the spring G is bent,
and the rod B is fed downwards. If the arc is by these two feed actions reduced
to the required length the motion ceases, but if not the vibration of the frame H H
continues until this result is attained,

page_text: The lower electrode is carried on a rod which forms the core of a solenoid. This
solenoid is included in the main circuit, and as soon as the current is started it
draws down its core and strikes the arc.
In my provisional specification I proposed to employ for striking the arc, an
arrangement comprising a cylinder containing mercury and enclosing a core
carrying a piston at its lower end but as I no longer consider the arrangement in
question to be advantageous as I then deemed it I do not now make any special
claim in respect of its use.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what
I claim is
In an arc lamp,
1. A feeding device comprising slipper blocks or friction pawls and curved
springs the arrangement being such that each of these springs can be caused to
become less curved and the other at the same time to become more curved
and so on alternately thereby moving the slipper blocks or pawls forward and
back ward substantially in the manner described so as to feed the electrode.
2. The combination with the feeding device comprising slipper blocks or friction
pawls and curved springs as referred to in claim 1 of an electro magnet and a make
and break for operating the said slipper blocks or pawls substantially as described
for the purpose specified.
3. The use with a feeding device comprising slipper blocks or friction pawls
and curved springs as referred to in claim 1 of an electro motor whereby the said
feeding device is operated substantially in the manner hereinabove described.
1000
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W. LLOYD WISE,
Per James G. Stokes,
46, Lincoln's Inn Fields, London, W.C.,
Agent for the Applicant.