An Improvement connected with Electric Arc Lamps.
Year: 1892

page_text: Date of Application, 10th Mar., 1892
Complete Specification Left, 10th Dec., 1892-Accepted, 28th Jan., 1893
PROVISIONAL SPECIFICATION.
An Improvement connected with Electric Arc Lamps.
We, JOHN JAMES RATHBONE, of 10 Bramley Road, Notting Hill, Middlesex,
Electrical Engineer, and JAMES HOUGHTON, of 4 Sussex Mansions, Maiden Lane,
Strand, London, C.E. do hereby declare the nature of this invention to be as
follows:-
This invention consists of a rolling armature to roll upon the end of a solenoid
core or of an electro-magnet.
To enable the application of the invention to be understood, we employ what may
be termed a rolling armature which rolls back and forth on the top end of the core
of a solenoid or electro-magnet according to the current passing through the
solenoid. This rolling armature has a groove in the centre about th of an inch
deep which is covered with india rubber or any suitable substance to form a clutch
to the string that works the carbons of the arc lamp, this string or cord is taken
once round the groove, which effectually prevents its slipping when the armature
rolls towards the centre of core for making the arc. As the carbon burns away the
current becoming less, the armature rolls from the centre of core to its outer edge
where it is stopped from rolling but allowed to revolve by a circular concave plate,
against which the rolling part abuts. By this arrangement the rolling armature is
always in reach of the electro-magnet and will again be pulled over towards the
centre of aforesaid core as the current strength increases.
When rolling, the armature
in actual contact with the core on which it rolls
but when revolving, it is on the edge of the core. It is prevented from rolling out
of a straight line back and forth by the ends working against a flat surface which
always keeps it in a straight line.
Dated this 10th day of March 1802
H. GARDNER,
Patent Agent, 166, Fleet Street, London,
Agent for the said John James Rathbone and James Houghton.
COMPLETE SPECIFICATION.
An Improvement connected with Electric Arc Lamps.
We, JOHN JAMES RATHBONE, of 10 Bramley Road, Notting Hill, Middlesex,
Electrical Engineer, and JAMES HOUGHTON, late of 4 Sussex Mansions, Maiden
Lane, Strand, but now of 103 Fulham Road London, C.E. 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 consists of a rolling armature to roll upon the end of a solenoid
core, or (of an) electro-magnet inserted in the circuit of an electric arc lamp for the
purpose of striking an arc between the carbons and regulating and controlling the
feed of same.
To enable our invention to be completely understood, we have annexed the
accompanying sheets of drawings, in which
Figure 1 is a sectional elevation of an arc lamp constructed and operated according
to our invention, Figure 2 being a plan of same, and Figure 3 à side clevation of
the rolling armature.
Figures 4, 5, and 6, are front and side elevation and plan respectively of a modified
arrangement of rolling armature.
Figures 7, 8, 9, and 10 show a modification..

page_text: Referring to Figure 1; A is an electro magnet surmounted with a channel trough B
of any suitable non-magnetic material, and in which an armature C of soft iron, or
other suitable magnetic material is free to roll and revolve in the manner hereinafter
fully described, said armature C is provided with a groove D to form a recess for
the reception of any suitable resilient material, such as an india rubber ring. To
obtain a suitable grip, the cords F, F, are wound once completely around the
armature C, the ends thereof being conducted over suitable grooved pullies G, G,
to the positive and negative carbon carriages H, H', to which they are securely
attached in the ordinary manner.
The armature C is formed with flat ends to work against the sides of the channel
trough B, and is thereby prevented from working out of the straight line during the.
back and forth rolling, or revolving action when same is in operation.
The concave plates or the stops I, I, form an abutment, against which the armature
is free to revolve, and they also prevent said armature from rolling beyond the
magnetic attraction. of the solenoid or electro magnet A.
In the modified arrangement indicated at Figures 4, 5, and 6, the rolling armature C
is of sufficient length to embrace the magnetic force of two solenoids, or electro
magnets A, A, and may be grooved and wound with the cords F, F, in the same
manner as spoken of in reference to Figures 1, 2, and 3 but we prefer the india
rubber ring, or other suitable material, such as asbestos to be placed over the
armature C, and the cord F simply hung upon same in the manner clearly shown in
Figure 4, as by this means, a sufficient grip upon the cord is obtained to prevent
same from slipping without the risk of any entanglement or hitch detrimental to the
successful operation of the lamp ensuing.
By inserting the pins J, J, in the armature C and causing same to move in the
slot K, we reduce the amount of surface in frictional contact with the frame or
trough B, and dispense with the concave abutment pieces obtaining at the same
time greater sensitiveness and freedom of action. The pins of the roller may roll
level on the frame with or without slots when off the magnet, but when the roller.
is on the magnet, the pins are raised from the frane owing to there being a slight
incline from the end of the roller's path to the opposite side.
The electro magnet or magnets A is or are wound in series with the main circuit
and the carbons, and when excited by the passage of the current to the lamp,
cause the armature C to roll towards, the centre of the core A' by magnetic
attraction until an arc of sufficient resistance is struck to balance the E.M.F. of
the, current in the wires, therefore as the current increases, the armature C will be
drawn still nearer the magnetic core A.' to lengthen the arc by letting out the
cord F of the lower carbon H, and drawing up the cord F of the upper
carbon H, H', a corresponding amount. If on the contrary, the current
diminishes, or the arc resistance increases, the preponderating weight of the upper
carbon carriage H' will overcome the pull of the magnet A upon the armature C,
and cause same to roll off the core A' towards the abutment stop I, so that as the.
carbons burn away it may freely revolve upon itself to feed the carbons together
until the correct balance is obtained by giving out and taking up the cords F, F,
in the reverse direction to that before described in reference to striking the arc.
It will be observed that the line of contact of the armature C may be on or near
the edge of the core A' before it can revolve upon itself, or else the adhesion
caused by the magnetic attraction acts as a brake upon same, allowing it to roll
only, and not to revolve upon itself, it is the distinction between these two
movements that we rely upon to perform the separate functions of striking the arc,
and feeding the carbons.
In the example shown at Figures 4, 5, and 6, the movement of the armature is'
limited by the length of the slot K, and it is at the same time lifted free from
contact with the base of the trough B in which it rolls for the purpose before
described, the method of operation in all other respects being the same as described
with reference to Figures 1, 2, and 3.
To ensure the constant action of the roller with a small ainount of friction the

page_text: modification shown at Figures 7 and 8 answers very well. The roller C is mounted
to revolve loosely on a spindle or axle J which is supported by two brass
wheels C, C', the same diameter as the roller. When feeding on the electro-
magnet cores A', A¹, the roller C and wheels C, CI, revolve together but when off
the cores, the outside wheels C¹, C', take the bearing and leave the roller free to
turn on the axle owing to a gap a, b, Figure 9, being made for the roller to
turn in which prevents friction between the bottom part of the roller, and the
bed of the frame cradle.
Although we have described and shown the solenoids or electro magnets A as
being connected in series with the carbons and circuit, we may if desirable
additionally wind them with a layer or so of wire of a higher resistance in shunt
with the circuit to more rapidly de-magnetise the core A' without in any way
departing from our invention.
The reason for the roller revolving upon itself before coming to the end of its
path, is that the pull from the weight of the upper carbon carriage acting on the
top or opposite part of the circle of the roller to the pull of the electro-magnet
causes the roller to revolve upon itself when the magnetism of the electro-magnet
becomes sufficiently feeble to allow this motion to take place. A stop 1¹ prevents
the roller from approaching too near the centre of cores of electro-magnets.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed we declare that what we
claim is
1. In an electric arc lamp, the combination with a solenoid or electro-magnet or
magnets of a rolling or circularly reciprocating and revolving armature in the
manner and for the purpose substantially as herein described and shown.
2. The employment of a revolving, rotating, or travelling armature for use in
connection with a solenoid or electro-magnet of an arc lamp substantially as set
forth.
H. GARDNER,
Patent Agent, 166, Fleet Street, London,
Agent for the said John James Rathbone and James Houghton.