Improvements in Electric Aro Lamps.
Year: 1895

page_text: Improvements in Electric Aro Lamps.
I, ROWLAND HILL BARNETT of Mosley Street, in the City and County of
Newcastle-on-Tyne, Electrical Engineer, do hereby declare the nature of this
invention to be as follows:-
My invention of improvements in electric arc lamps applies to that description
of arc lamps wherein the arc is struck by the operation of a solenoid as is well
understood, and wherein it is maintained by the combined operation of the striking
solenoid and a clock work device set in motion by the superior weight of the upper
carbon bolder over that of the under carbon holder.
The essential features of my improvements are the extreme simplicity and
cheapness of the mechanism and the steadiness and efficiency of its operation.
I use many of the parts which are common to all such lamps, such as the ordinary
form of carbon holder, the balance arrangement by a chain (to the opposite ends of
which both carbon holders are attached) running over a pulley, and tending by the
greater weight of the upper carbon holder to bring the carbons or carbon holders
into contact as is well understood, the solenoid regulator and the clockwork device
operated by the movement of the chain supporting the carbon holders over the
pulley before described...:
Upon the axis of the chain pulley I fix a toothed wheel of say 40 or any
convenient number of teeth and into this toothed wheel I gear a pinion of say
5 teeth, but the proportions and number of teeth within considerable limits are not
essential features of my invention. On the axis of the pinion 1.fix a star wheel of
say 12 teeth, and I prefer to construct this star wheel so that it serves the double
purpose of a star wheel and a fan. Both the pulley, and its toothed wheel and the
star wheel are fixed in a frame so as to be always in gear with each other and this
frame turns upon a centre like a weighbar at the end opposite to the.star.wheel,it
has a bar of soft iron attached to it entering within the solenoid which is fixed
above the moveable frame, in such way as that when the current increases in
strength the bar is drawn further within the solenoid and the frame lifted. Between
the centre on which the frame turns and the bar which enters the solenoid or at
any other convenient spot, I attach what is technically called a dash pt the
operation of which is pneumatically to control to some extent undesired suddenness
of the movement of the mechanism. I further provide a stop on the frame of the
lamp to prevent the contingency of one carbon being burned out and the current
maintained at the cost of the carbon holder. I form the carbon holder of two
semi-circular pieces of carbon with two metalic plates attached by screw bolts so
that if by fracture of a carbon or other accidental cause the arc should be made
between the other carbon and a holder a minimum of damage may be done and also
the carbons may be burned, more closely.
When running a single lamp I use the main current in the solenoid, but when
running a set of lamps in series I use a shunt current. The above is almost a
complete description of my improved, lamp, and it remains only to add one point
more as to its operation. As the frame carrying the pulley and the dash pot is
lowered (by the lengthening of the arc and consequent diminution of current and
therefore less potent action of the solenoid) its other end carrying 'the star wheel' is
.

page_text: raised until it reaches a point where the star wheel is liberated from a fixed stop
attached to the bed plate of the lamp; and on this liberation it begins to revolve
in the direction required to diminish the length of the arc; and so long as the
current of electricity is inadequate sufficiently to excite the solenoid to the required
degree this star wheel remains free to revolve, and the carbons are by that
revolution brought nearer together. The revolution of the star wheel is thereby
stopped by its contact with the stop. This is however not a perfectly simple stop
inasmuch as the stop is tapered or bevilled off so that a deeper gearing of the stop
and the star wheel forces the latter backwards in a slight degree and thereby more
finely adjusts the length of the arc. The arc is also adjusted in the same direction
by the more or less altered position of the chain pulley due to the movement of the
frame.
The degree of taper in the stop and of movement of the frame carrying the
It is
pulley are adjusted so as to give the required degree of sensitiveness.
manifestly possible that altho' the point of the stop is sharp, and the outside edge
of the star wheel or fan are sharp, it might happen that they should fall into such
contact edge and edge as to lose the adjustments I have referred to; and therefore.
I provide by spring or otherwise for the movement of the stop so as to release
itself in the event of such contingency arising.
Dated this Fourteenth day of August 1895.
J. JAMESON,
Akinside Hill, Newcastle-on-Tyne, Agent for Applicant.
3.
COMPLETE SPECIFICATION.
7
Improvements in Electric Arc Lamps.
I, ROWLAND HILL BARNETT of Mosley Street, in the City and County-of
Newcastle-on-Tyne, 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 :-
My invention of improvements in electric arc lamps applies to that description
of arc lamps wherein the arc is struck by the operation of a solenoid as is well
understood, and wherein it is maintained by the combined operation of the striking
solenoid, and a clock work device set in motion by the superior weight of the upper
carbon holder over 'that of the under carbon holder.
The essential features of my improvements are the extreme simplicity, and
cheapness of the mechanism, and the steadiness, and efficiency of its operation.
I use many of the parts which are common to all such lamps, such as the ordinary
forms of carbon holders, the balance arrangement by a chain (to the opposite ends
of which both carbon holders are attached) running over a pulley, and tending by
the greater weight of the upper carbon holder to bring the carbons or carbon
holders into contact as is well understood, the solenoid regulator, and the clockwork
device operated by the movement of the chain supporting the carbon holders over
the pulley before described.
Upon the axis of the chain pulley I fix a toothed wheel of say 40 or any
convenient number of teeth, and into this toothed wheel I gear a pinion of say
5 teeth, but the proportions, and number of teeth within considerable limits are not
essential features of my invention.
On the axis of the pinion I fix a star wheel of Bay 12 teeth, and prefer to
construct this star wheel so that
serves the double purpose of a star wheel, and a
fan. Both the pulley and its toothed wheel, and the star wheel are fixed in a frame
'so as to be always in gear with each other, and this frame turns upon a.centre. like
a weigh bar. At the end opposite to the star wheel it has a bar of soft iron attached

page_text: to it entering within the solenoid which is fixed above the moveable frame, in such
way as that when the current increases in strength the bar is drawn further within
the solenoid, and the frame lifted. Between the centre on which the frame turns,
and the bar which enters the solenoid, or at any other convenient spot, I attach
what is technically called a dash pot the operation of which is pneumatically to
control to some extent undesired suddenness of the movement of the mechanism.
1 further provide a stop on the frame of the lamp to prevent the contingency of
one carbon being burned out, and the current maintained at the cost of the carbon
holder. I form the carbon holder of two semi-circular pieces of carbon with
2 metallic plates attached by screw bolts so that if by fracture of a carbon or other
accidental cause the arc should be made between the other carbon, and a holder, a
minimum of damage may be done, and also the carbons may be burned more
closely.
When running a single lamp I use the main current in the solenoid, but when
running a set of lamps in series I use a shunt current. The above is almost a
complete description of my improved lamp, and it remains only to add one point
more as to its operation.
As the frame carrying the pulley and the dash pot is lowered (by the lengthening
of the arc, and consequent diminution of current, and therefore less potent action of
the solenoid) its other end carrying the star wheel is raised until it reaches a point
where the star wheel is liberated from a fixed stop attached to the bed plate of the
lamp. On this liberation it begins to revolve in the direction required to diminish
the length of the arc; and so long as the current of electricity is not adequate
sufficiently to excite the solenoid to.the required degree this star wheel remains
free to revolve, and the carbons are by that revolution brought nearer together.
The revolution of the star wheel is thereby stopped by its contact with the stop.
This is however not a perfectly simple stop inasmuch as the stop is tapered or
bevilled off so that a deeper gearing of the stop, and the star wheel forces the latter
backwards in a slight degree, and thereby more finely adjusts the length of the arc.
The arc is also adjusted in the same direction by the more or less altered position
of the chain pulley due to the movement of the frame. The degree of taper in the
stop, and of movement of the frame carrying the pulley are adjusted so as to give
the required degree of sensitiveness. It is manifestly possible that altho' the point
of the stop is sharp, and the outside edge of the star wheel or fan are sharp it
might happen that they should fall into such contact edge and edge, as to lose the
adjustments I have referred to; and therefore I provide by spring or otherwise for
the movement of the stop so as to release itself in the event of such contingency
arising.
In the drawings hereto attached Fig. 1. (Sheet 1) represents a side elevation ;
Fig. 2 (Sheet 7) a plan; Fig. 3 (Sheet 2) an end elevation of a lamp according to
my invention.
The same letters indicating the same parts in each drawing.
A. A. represents the solenoid before described. B. B. being a hollow core of
soft iron operated upon by the passage of current. C. C. is what I have called the
frame which carries D. the dashpot. The fixed piston fitting the dash pot being
shewn in dotted lines and marked E. This frame carries also what I called the
chain wheel F, fast on its axis, and fast on the same axis the toothed wheel G.
gearing into the pinion of the axis of what I have called the star wheel H.
both pinion and star wheel being fast together. The frame C. C. moves up
and down on the axis, which is the axis of the chain wheel and toothed wheel F.
and G. The chain (shewn partly in full and partly by lines) gears fast into
the chain wheel F. That end of the chain marked J. is attached to the upper
and heavier carbon holder, and the end marked K. is attached to the lower,
and lighter carbon holder. In these circumstances it will be readily seen that
if the soft iron bar B. B. is pushed up within the solenoid, so that an
impediment exists, the superior weight of the upper carbon holder will be unable
to operate the chain wheel F. and with it the toothed wheel G. because the

page_text: pinion geared on to the axis of the star wheel H. is stopped from revolution
by a spoke of the star wheel engaging with a stop L. But ordinarily there is no
impediment to this movement in the shape of the stop L. which according to
the more or less depressed position of the frame C. C. at the solenoid end
brings a vane of the star wheel H. clear of the stop L. or leaves it in the
position to prevent the rotation of the star wheel; and therefore to hold the
carbons of the lamp at a fixed distance from each other.
Now the operation of the lamp is as follows :-I will for convenience describe
first the operation of my lamp when used as what is known as a series lamp, and
then explain the slight modification which is required when it is to be used as what
is known as a shunt lamp. In a series lamp the carbons are first brought together
before the current of electricity is applied. The course of the current is through
the solenoid, and thence through the carbons.
Owing to the free passage of current while the carbons are in contact there is
strong action of the solenoid, the frame is thereby lifted, and the chain being drawn
upon thereby, the arc is struck, and a vane of the star wheel being engaged against
the stop the are so formed is maintained. As the carbons burn away the current
becomes more feeble in the solenoid, and the soft iron core is lowered in consequence;
but as that end of the frame is lowered the other end is lifted, the star wheel is
brought out of contact with the stop L. and becomes thus free to revolve, when the
weight of the upper carbon holder sets the clock work mechanism in action, and
the carbons are approached to the extent of the movement. The approach of the
carbons increases the current, and the power of the solenoid is thereby increased,
and the frame thereby moved into the position in which the stop interposes to
prevent further revolution of the star wheel, and consequently any nearer approach
of the carbons.
The stop is shewn separately in Fig. 4. and 5. & 6 (Sheet 2). It will be observed
that the slope on the stop must have an action on the exact position of the star
wheel, in proportion to the depth to which what may be called the gearing of one
into the other, is engaged. The slope is so proportioned as to give a finer
adjustment to the arc than would be possible by the action of the solenoid by
itself.
The action of the dash pot is to prevent the impetus due to the movement of the
core of the solenoid, and the other moving parts from carrying the frame beyond a
desired position.
In the stop there is a peculiarity which prevents the accidental sticking of the
star wheel upon the apex of the stop. This is illustrated in Fig. 4. and 5 and 6.
If the star wheel should by chance fall with one of the vanes upon the very apex
of the stop, it is conceivable.that the operation of the lamp might be stopped. The
current would be perhaps too strong, and its effect would only be to exert increased
pressure on the stop. To provide for this contingency the stop is supported on a
spring M. which would give way if the pull of the solenoid came upon it. As the
stop yields to the spring the star wheel is of course proportionately lowered, and,
at a point within the range of the spring, I cause the engaged vane of the star
wheel to fall upon the sloping.edge of a fixed inclined plane N. which bears the
pressure due to the pull of the solenoid, and which is inclined in the direction
required to give the requisite movement, and freedom to the star wheel.
Fig. 4. shews the normal position of the stop..
Fig. 5 shews the spring in action. Fig. 6 is an end view of the same mechanism.
In a shunt lamp the carbons are held slightly apart (that is to say arc distance
apart) by a counterweight or spring acting upon the frame C. C. when the current
is applied that portion of it which passes through the shunt acts against the
counterweight or spring and cause the carbons momentarily to touch. Owing to
this contact affording free passage for the current the action of the shunt is
weakened, and by the counterweight or spring the carbons are separated to the
required distance, and the operation of the shunt thereafter exercises control as in
the series lamp.

page_text: Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what.
I claim is
1st. The general arrangement of parts substantially as described.
2nd. The method of releasing the vane of the star wheel if it should fall upon.
the apex of its stop.
Dated this Fourteenth day of Max 1896.
J. JAMESON,
2 Akinside Hill, Newcastle-on-Tyne, Agent for Applicant..