Year: 1886

page_text: I, EDGAR ARTHUR ASHCROFT, of N° 14 Finsbury Circus in the City of London,
Electric Engineer, do hereby declare the nature of this invention to be as
follows:-
According to my present invention I arrange an electro dynamic motor included
in the main circuit of an arc lamp, to operate upon an endless travelling cord or
chain in a loop of which the one carbon is supported, which chain is also acted
upon either by another electro motor or by a regulated frictional device included
in a shunt circuit, that will be presently described, so that while the regulation of
the distance of the carbons is effected by the action of the main current motor
tending to separate the carbons, in opposition to the action of the shunt motor or
frictional device tending to allow them to approach, the several moving parts are
kept in continuous rotary motion and thus by maintaining the coefficient of friction
of these parts constant, I insure a very uniform action, free from jerky motion.
According to one arrangement for carrying out this invention, an electro motor
in the lamp circuit and another one in a shunt circuit each impart rotary motion
to a pitch wheel or grooved pulley over which passes the endless chain or cord.
The two pitch wheels or pullies may have their axes either side by side or in line
with each other; I will assume them to be side by side, in which case they are both
made to revolve in the same direction. The endless cord or chain passes over these
wheels in such a manner that it hangs in two loops, one situated between wheels
and the other passing from the outside of the one wheel to the outside of the
other. In the last named loop the holder of the upper carbon is suspended by
means of a grooved pulley resting in the loop, while in the other loop a balance
weight is hung if grooved pullies are employed; if pitch wheels are used, a balance
weight can be dispensed with, and the loop may be partly carried on a tray. Thus
it will be seen that if both wheels rotate at the same speed when the lamp is in
the normal working condition, they will cause the chain to travel continuously
round the loops without altering the position of the carbon, but if from any cause
the resistance of the lamp circuit increases; then as the current thereof will decrease
while that of the shunt circuit will increase, the resulting increase of speed of the
shunt motor and decrease of speed of the main circuit motor will cause the wheel
of the former to deliver the chain into the loop of the carbon holder faster than
the wheel of the main circuit motor draws the chain up from that loop and delivers
it into the other one, and the consequence hereof will be that the carbon loop will
D

page_text: be lengthened, thus bringing the carbons nearer together, while the other loop will
be shortened. By this means the resistance of the lamp circuit will be reduced
again by the approach of the carbons until it attains the normal degree, when the
two motors will again revolve with the same speed, maintaining the upper carbon
in its adjusted position. If, on the other hand, the lamp circuit's resistance should
decrease from any cause, the reverse action to that above described will take place,
causing the carbon loop to be shortened and consequently moving the carbons
farther apart until the normal resistance has been reestablished.
When the pitch wheels or grooved pullies are arranged with their axes in line
with each other, the two loops of the cord or chain will hang, one on each side of
the wheels or pullies, which in this case revolve in opposite directions.
Although I have spoken of the carbon being held stationary when the lamp
circuit's resistance is normal, yet, as owing to the consumption of the carbons there
is a continual tendency to increase the said resistance, there will always be a very
slight differential motion between the two motors, resulting in the required down-
ward feed of the upper carbon.
According to another modification I dispense with the shunt motor actuating the
one pitch wheel or grooved pulley, the rotation of which is controlled by the
frictional contact of a spring or brake, the action of which can be lightened by
means of an electro-magnet included in the shunt circuit. When the lamp works
with the normal resistance, 'the frictional resistance of the brake of this wheel or
pulley is so adjusted that it will allow the chain or cord to pass over the latter as
fast as the wheel or pulley of the series motor draws it up, in which condition the
carbon holder in the one loop and the weight in the other will remain stationary;
but when, owing to an increase in the lamp circuit's resistance, the speed of the
motor decreases, while at the same time the increase of the shunt current causes
the electro-magnet to lessen the pressure of the brake, the consequent decreased
resistance of the wheel or pulley will allow the weight or carbon holder to pull
down its loop of the chain or cord, in opposition to the weight in the other loop,
and the carbons being thus brought nearer together the resistance of the lamp
circuit will be again diminished by the shortening of the arc. The motor will now
again run at its normal speed, and the brake will again oppose the normal resistance
to the rotation of it's wheel, owing to the decrease of the shunt current, and
consequently the carbon will again become stationary.
If, on the other hand, the lamp circuit's resistance sinks below the normal, the
reverse action to that above described will take place, namely the motor wheel will
draw up the carbon loop at an increased speed while the resistance of the friction
wheel will be increased by an increase of the brake action, and consequently the
'carbons will be separated so as to increase the lamp circuit's resistance.
Although in all the above described arrangements I prefer to actuate the upper
carbon holder in the described manner, yet, the arrangement might be readily
modified so as to actuate the lower carbon holder, the upper one remaining
stationary. The lower carbon holder would in this case be supported in the loop
that is raised when the lamp circuit's resistance increases, instead of in the loop
that is lowered.
In the above described arrangements the current is conveyed to the carbon
through the endless chain or cord, which may be arranged to make the contact
with the lamp circuit in any convenient manner such as through the wheel of one
of the motors or otherwise.
ABEL & IMRAY,
Agents for the Applicant,

page_text: I, EDGAR ARTHUR ASHCROFT of N° 14 Finsbury Circus in the City of London,
Electric 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:-
According to my present invention I arrange an electro dynamic motor included
in the main circuit of an arc lamp to operate upon an endless travelling cord or
chain in a loop of which the one carbon is supported, which chain is also acted
upon either by another electro motor or by a regulated frictional device included
in a shunt circuit, that will be presently described, so that while the regulation of
the distance of the carbons is effected by the action of the main current motor
tending to separate the carbons, in opposition to the action of the shunt motor or
frictional device tending to allow them to approach, the several moving parts are
kept in continuous rotary motion and thus by maintaining the coefficient of
friction of these parts constant I insure a very uniform action, free from jerky
motion.
According to one arrangement for carrying out this invention, an electro motor
in the lamp circuit and another one in a shunt circuit each impart rotary motion
to a pitch wheel or grooved pulley over which passes the endless cord or chain.
The two pitch wheels or pullies may have their axes either side by side or in line
with each other; I will assume them to be side by side, in which case they are
both made to revolve in the same direction. The endless cord or chain passes
over these wheels in such a manner that it hangs in two loops, one situated
between the wheels and the other passing from the outside of the one wheel to
the outside of the other. In the last named loop the holder of the upper carbon
is suspended by means of a grooved pulley resting in the loop, while in the other
loop a balance weight is hung if grooved pullies are employed, or if pitch wheels
are used, a balance weight can be dispensed with, and the loop may be partly
carried on a tray. Thus it will be seen that if both wheels rotate at the same
speed when the lamp is in the normal working condition, they will cause the cord
or chain to travel continuously round the loops without altering the position of
the carbon, but if from any cause the resistance of the lamp circuit increases, then
as the current thereof will decrease while that of the shunt circuit will increase,
the resulting increase of speed of the shunt motor and decrease of speed of the main
circuit motor will cause the wheel of the former to deliver the chain into the loop
of the carbon. holder faster than the wheel of the main circuit motor draws the
chain up from that loop and delivers it into the other one, and the consequence
hereof will be that the carbon loop will be lengthened, thus bringing the carbons
nearer together, while the other loop will be shortened. By this means the resistance
of the lamp circuit will be reduced again by the approach of the carbons until it
attains the normal degree, when the two motors will again revolve with the same
speed, maintaining the upper carbon in its adjusted position. If on the other hand
the lamp circuits resistance should decrease from any cause, the reverse action to
hat above described will take place, causing the carbon loop to be shortened and
consequently moving the carbons farther apart until the normal resistance has been
e-established,

page_text: when
axes
спец
the pitch wheels or grooved pullies are arranged with
line with each other, the two loops of the cord or chain will hang, one on each
side of the wheels or pullies, which in this case revolve in opposite directions.
Although I have spoken of the carbon being held stationary when the lamp
circuit's resistance is normal, yet, ns,, owing to the consumption of the carbons,
there is a continua! tendency to increase the said resistance, there will always be a
very slight differential motion between the two motors resulting in the required
downward feed of the upper carbon.
According to another modification I dispense with the shunt motor actuating
the one pitch wheel or grooved 'pulley, the rotation of which is controlled by
the frictional contact of a spring or brake, the action of which can be lightened.
by means of an electro-magnet in the shunt circuit as will be presently described.
Although in all the above described arrangements I prefer to actuate the upper
carbon holder in the described manner, yet, the arrangement might be readily
modified so as to actuate the lower carbon holder, the upper one remaining
stationary. The lower carbon holder would in this case be supported in the loop
that is raised when the lamp circuit's resistance increases, instead of in the
loop that is lowered.
In the above described arrangements the current is conveyed to the carbon
through a roller or brush in contact therewith, or by other suitable means.
Figs. 1 and 2 of the accompanying drawings shew views at a right angle to
each other of a lamp constructed according to the first above described arrange-
ment. In Fig. 2 the motor C is removed, leaving its pulley D, for the sake of
.clearness AA is the framing of the lamp, carrying at bottom the lower carbon
holder B and at top two electro motors C and C', of which C is in series, while C¹
is in a shunt circuit of the lamp. The rotating armature spindles of these motors
each carry a grooved pulley D D¹ over which is passed an endless cord or chain E
in such manner as to hang in two loops, in one of which is suspended a weighted
pulley H, the weight being about sufficient to balance the upper carbon holders B¹
which is suspended in the other loop. The axes of the motors being arranged to
revolve in contrary directions, and their action being so adjusted as to cause the
pullies D D¹ to revolve with exactly the same speed when the lamp is working
with the normal resistance, it will be seen that the cord E will be made to travel
continuously round the two loops in the direction of the arrow, without altering
the position of the upper carbon, but when owing to the burning away of the
carbons, the lamp circuits resistance is increased, the speed of the motor C will
diminish while that of the motor C¹ will be increased owing to the increase of the
shunt current, and consequently the pulley D¹ will deliver the cord downwards
into the carbon holder loop faster than it is drawn up from the same by the
pulley D, and the loop being thus lengthened the carbons will be made to approach
until the lamp circuit's resistance is again reduced to the normal, whereupon the
motors will again revolve at the same speed, and the upper carbon will again
become stationary. The reverse action will take place when the lamps circuits
resistance is reduced below the normal: The upper carbon is guided in its motion
by means of a crosshead K sliding upon the bars of the framing A. The current is
made to pass from the terminal I to the insulated bar A¹ of the framing, thence
through crosshead K (insulated from the bar A) carbon B' B and framing A to the
coils of the motor C and thence to the insulated terminal I. From the terminal I¹
a shunt current also passes through the coils of the motor 0 and thence to
the terminal I. L is an incandescent lamp included in the shunt circuit, for
compensating by its decreased resistance when heated to incandescence for the
increase of resistance due to the heating of the shunt motor coils as described in my
patent No 13612 of 1885.
=
17
Fig. 3 shews a diagram view of the second above described modification of my
invention. D is the pulley of a motor in the lamp circuit, caused to rotate in the
direction of the arrow, so as to raise the endless cord E from the loop of the carbon
holder G and deliver it into the loop of the weighted pulley H, which in this case
-

page_text: is somewhat lighter than the carbon holder. The second pulley D¹ over which the
cord E passes would revolve freely upon its axis, were it not controlled by a spring
brake lever O, that is pressed upon by a screw M carried by a spring arm M₁,
which tends to press the brake against the wheel, but which when the lamp is at
work is acted upon by an electro-magnet N, the coil of which is included in a
shunt circuit of the lamp, and which in attracting the arm M¹ tends to reliėve
the pressure upon the brake lever O and thus to lessen the frictional resistance to
rotation of the pulley D¹. The pressure of the break is so adjusted that when the
lamp works with its normal resistance, the pulley D' will allow the cord to pass
down into the carbon-holder loop as fast as it is drawn up by the pulley D of the
series motor, but when owing to an increase in the lamp circuit's resistance, the
speed of the pulley D decreases, while at the same time the increased current
passing through the shunt circuit causes the magnet N to relieve the pulley D'¹ of
brake pressure, the weight of the carbon and carbon holder, preponderating over
that of the weighted pulley H, will lengthen its own loop, thus allowing the
carbons to approach each other and thereby lessening the resistance of the lamp
circuit again till the normal condition is attained, whereupon the pulley D will
again rotate at the normal speed, and the pulley D' will revolve with the normal
frictional resistance, thus maintaining the upper carbon stationary. If on the other
hand the lamp circuits resistance is decreased below the normal, the speed of D
will be increased, while owing to the decrease of the shunt current, the brake will
be applied with increased force to the pulley D¹, increasing its resistance to rotation,
and causing the carbon-holder loop to be shortened, and the carbons separated,
until the normal resistance is again established by the lengthening of the arc.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is :-
1. In an electric arc lamp, the method of keeping the moving parts of the
mechanism for regulating the carbons in continuous motion in order to maintain
the coefficient of friction constant, by arranging in combination therewith and
endless cord or chain from a loop of which the one carbon holder is suspended, and
which is caused to travel continuously by the said mechanism, substantially as
herein described.
2. In an electric arc lamp, suspending the one carbon holder in a loop of a cord
or chain, that is made to travel continuously over two pullies or wheels, one of
which is continuously rotated by an electro motor included in the lamp circuit,
while the other is rotated by an electro motor included in a shunt circuit, the
action of the two motions being such that while the one tends to shorten the loop
containing the carbon holder, the other tends to lengthen the said loop, substantially
as herein described with reference to Figs. 1 and 2 of the accompanying drawings.
3. In an electric arc lamp, suspending the one carbon holder in a loop of a
cord or chain that is made to travel continuously over two pullies or wheels, one
of which is continuously rotated by an electro motor included in the lamp circuit,
while the other is acted upon by a brake controlled by an electro magnet whose
coils are included in a shunt circuit, the action of the first named pulley being
such as to tend to shorten the loop containing the carbon holder, while that of the
second pulley is such as to deliver the cord or chain into such loop more or less
freely according as it is acted upon by the brake, substantially as herein described
with reference to Fig. 3 of the drawings.
T
1000
ABEL & IMRAY,
Agents for the Applicant,