Year: 1889

page_text: I, JOHN ROPER of Trafalgar Street, Bradford in the County of York, Electrician,
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:-
The improvements to which my invention principally relates consist in an arrange-
ment whereby the armature of the main coil, when attracted to the cores and in its
normal or working position, lifts a worm into gear with the teeth surrounding the
periphery of the pulley from which the upper carbon is suspended.
The worm when in gear with the teeth of this pulley actuated intermittingly by
means of a vibrating spring suspended at the end of the shunt coil which spring
is connected to a ribbon or strap passing round a drum which actuates the arbor upon
which the worm is mounted.
This motion of the worm slowly rotates the pulley with which it engages and
thereby lowers the upper carbon holder which is suspended by means of a chain from
the pulley.
In order to enable my invention to be fully understood, I will proceed to describe
the same with reference to the accompanying drawings in which Figures 1, 3 and 4
are representations of the front, back, and side elevations respectively of my improved
mechanism for electric arc lamps, and Figure 2 represents a plan of the same.
Similar letters refer to similar parts in all the drawings.
Upon the base plate represented at L is mounted the main coil A A which actuates
the armature C hinged at a. Near the end of the armature C is fixed the finger J
which is in contact with the underside of the worm F which is supported by the
standard K. When the full current of electricity is passing through the main
coil A A the armature is lifted thereby raising the linger J and with it the worm F
which engages with the teeth of the pulley D. and at the same time causes the pulley
to rotate a short distance, thereby separating the carbons or rather raising the upper
carbon from the lower one to the required distance, or "striking the arc.'
After the light has been in operation a short time and the consumption of the
carbon points has caused a greater space and consequently greater resistance to
intervene between them, the current through the shunt coil B which is carried upon
the standard H becomes stronger, whereby the arunature d of the shunt, coil is attracted
and the spring e e carried by the armature is withdrawn from its contact with the
screws which pass through the bracket j, and the current being thus broken the
spring comes into operation and draws the spring e e again into contact with the
points of the screws A this rebounding motion stretching the strap or ribbon / tightly
k

page_text: round the drum E and causing it to rotate slightly. This slight rotation of the drun
is communicated to the worm F which worn works upon a pin n fixed into and
projecting from the arbor. The rotation of the worm engaging with the teath of
the pulley 1 releases a short length of the chain which passes over the pulley
thereby lowering the upper carbon to the required distance when the strength of the
current is re-established and the worm conses to rotate.
Sufficient friction is applied to prevent the drum E from revolving too freely by
means of the cloth washer placed beneath it and against which the drum is pressed
by means of the spring C acting against the top of the spindle or arbor & upon which
the drum is mounted.
Instead of the strap or ribbon held in tension by the spring g, a pawl, catch, or
toothed rack may be employed which is actuated by the spring or armature of the
shunt coil, which pawl engages with teeth formal on the periphery of the drum E
whereby the worm is rotated by the recoil of the spring in a similar manner to that
caused by the strap or ribbon.
The steel wire acts as a spring to regulate the tension withdrawing the armature d
from the cores of the shunt coil B, and the amount of this tension is regulated by
means of a set-sorew acting upon the lever p in which the wire is fixed.
*
The pulley Dover which the chain passes is cast hollow and in the recess is fixed
the coiled spring one end of which is attached to the inner side of the periphery of
the pulley and the other and to the boss of the bracket G upon which the pulley is
mounted.
The object of this spring is to partly balance the weight of the upper carbon holder
and to coil up the chains in the groove of the pulley when the top carbon is lifted up.
Portions of the tubular pillars which support the lower carbon and act as guides for
the upper carbon holder are represonted at M.
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 1
claim is.
1. In the mechanism of an electric are lamp, in combination with the armature of
the main coil the finger J attached to the armature and lifting into gear the worm F
which thereby engages with the teeth of the pulley from which the carrier of the upper
carbon is suspended.
2. In the mechanism of an electric are lamp the worm F in combination with and
working on the same spindle as the drum E, the strap or ribbon or its equivalent
pawl, rack, or catch actuated by the spring or armature of a shunt coil all constructed
and operating substantially in the manner and for the purpose described and
represented in the accompanying drawings.
3. In the mechanism of an electric arc lamp the general arrangement of the various
parts hereinbefore described for raising or lowering the adjustable carbon automatically
as required.
4. In the mechanism of an electric arc lamp the grooved pulley represented at D
having teeth upon its outer edge combined with the coiled spring for the purpose
and operating substantially in the manner set forth.
Dated this Sixth day of February 1889.