Improvements in Electric Arc Lamps.
Year: 1892

page_text: Date of Application, 20th Aug., 1892
Complete Specification Left, 20th Apr., 1893-Accepted, 20th May, 1893
PROVISIONAL SPECIFICATION.
Improvements in Electric Arc Lamps.
I, JAMES BROCKIE, of Fairview, Tyson Road, Forest Hill, in the County of
Kent, Engineer, do hereby declare the nature of this invention to be as follows:-
This invention relates to a construction and arrangement of brake or clutch to
control the movement of the carbons in electric are lamps so as to give an effective
control and keep in adjustment for a considerable time. It also relates to a device
for retaining the weight of the carbon holders &c. upon the regulating lever when
the carbons are .consumed. It is especially applicable to that construction of
electric arc lamps in which there is a brake wheel which is turned by the descending
weight of the carbon holder of the lamp either by means of a cord or band passing
over it or by a pinion on the spindle gearing into a rack on the carbon holder.
According to my invention I arrange a bell crank lever pivotted on the same
axis as the brake wheel of the lamp; the one arm of this lever is controlled
directly by the magnets or solenoids usually employed to regulate are lamps of this
description. Near the end of the other arm is pivotted or fixed a brake lever or
clutch which is loaded by a weight or spring, so that the brake consisting of a
roller of india rubber or other suitable material is normally pressing against the
inside rim of the brake wheel so as to lock it in position.
The end of the brake lever or clutch is prolonged beyond the wheel and a stop
is provided so that when the lever is depressed far enough by the action of the
regulating coils, the stop will tilt the brake lever upwards and so the pressure of
the brake will be released and the wheel be permitted to slip or revolve and the
carbon allowed to fall. The controlling lever actuated by the solenoids is geared
with the brake lever or clutch by means of a pin or link engaging in the first
mentioned arm of the bell crank lever. The brake can also be arranged to act on
the outside periphery of the wheel, in which case the second arm of the bell crank
lever is extended beyond the brake wheel and the brake lever or clutch is pivotted
so as to turn inwards towards the centre of the wheel and so cause its roller to
bear on the outside periphery, the locking or releasing action being similar.
In some constructions of lamps instead of using a bell crank lever as above
described employ a simple or straight lever actuated directly from the solenoids
or magnets by means of a link or otherwise.
For retaining the weight of the carbon holders &c. I arrange that the brake
wheel only makes nearly a complete revolution during the whole run of the carbons.
I form a projection on the brake wheel, so that when the carbons are nearly
consumed this projection comes in contact with a pin on the main regulating lever
of the lamp, which is conveniently placed for this purpose and so the weight of
the carbon holders &c. is taken direct by the lever in a simple manner. By placing
this pin on the lever at a greater or less distance from the centre, more or less,
weight may be placed on the lever as may be required.
This device is not absolutely necessary in a single carbon lamp but it is needful'
in a double carbon lamp in order that the second pair of carbons may burn at an
equal voltage to the first pair.
Dated this 20th day of August 1892.
ABEL & IMKAI,
Agents for the Applicant.

page_text: COMPLETE SPECIFICATION.
Improvements in Electric Arc Lamps.
I, JAMES BROCKIE, of 65 Lowth Road, Camberwell, in the County of London,
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 relates to a construction and arrangement of brake or clutch to
control the movement of the carbons in electric arc lamps so as to give an effective
control without requiring frequent adjustment. It also relates to a device for
retaining the weight of the carbon holders and carbons upon the regulating lever
when the carbons are consumed. It is especially applicable to that construction of
electric are lamps in which there is a brake wheel which is turned by the descending
weight of the carbon holder either by means of a cord or band passing over it or
by a pinion on the spindle gearing into a rack on the carbon holder as I shall
describe referring to the accompanying drawings.
Figs. 1 and 2 are respectively end and side views of the upper part of an
electrical lamp with regulating brake or clutch mechanism according to my inven-
tion. This mechanism is shewn in duplicate to suit two pairs of carbons in the
one lamp, the second pair kindling when the first pair is consumed, but obviously
for regulating only one pair of carbons, all the mechanism on the one side of the
central column F can be dispensed with. In what follows I therefore describe
only one set of the mechanism.
On a central axis are fitted free to revolve a hollow brake wheel D and fixed to
it but insulated from each other two cam discs and g, over and attached to which
pass conducting metal ribbons, the one attached to the upper or positive carbon
holder and the other on the opposite side attached to the lower or negative
carbon holder so that the former overbalancing the latter, the upper carbon tends
to descend causing the wheel D to revolve in the direction of the arrow drawing
up the lower carbon. In order to maintain equality of action notwithstanding
consumption of the carbons I prefer to give the discs ƒ and g the shape of snail
cams as described in my previous Specification No. 4248 of 1892, the upper carbon
gaining leverage and the lower carbon losing leverage as they become consumed.
By means of solenoids or electro magnets S S' of the kind usually employed in
regulating mechanism of electric lamps I effect regulation of the motion of the
wheel D and consequently of the carbons in the following manner. A bell crank
lever mm, pivotted on the axis of D, has a notch in its arm m' engaged by a pin
on a lever M worked by the cores of the solenoids S S¹. On the other arm m²
is pivotted a lever m³ on which is mounted a caoutchouc roller n, and a spring p
acts on the lever m³ in such a manner as to press the roller against the interior
of the periphery of the wheel D, making it operate as a brake preventing move-
ment of the wheel. When by the movement of the lever M resulting from increase
of resistance of the arc, the arm m³ is made to descend so far that the lever m³
meets an adjustable stop t, this lever is moved so as to relieve the pressure of i
against the periphery of D, thus taking off the brake and allowing D to turn
partly round so as to advance the carbons towards each other. The cam discs f
are of such diameter that they only make a single revolution during the whole
travel of the carbons, and I provide on a suitable part of the wheel Ď a tooth W
which when the wheel makes its revolution, the carbon being then nearly consumed
comes to bear against a pin r projecting from an arm of the lever M.
carbon holders with the nearly consumed carbons thus continue to be supported by
the lever M and to partake of its regulating movements. This is especially
advantageous when two pairs of carbons are employed, because as the regulating
mechanism thus continues to act throughout the period of consumption of the
second pair in the same manner as it had acted during consumption of the first
The

page_text: pair, the voltage for the second pair remains the same as for the first pair.
Although I have shewn the brake n arranged to bear against the interior of the
periphery of the wheel D, it might be mounted on the lower side of the lever m
so as to press against the exterior of the periphery of D.
8.
Having now particularly described and ascertained the nature of my said inven--
tion and in what manner the same is to be performed 1 declare that what I
claim is :-
For regulating the feed of carbons of an are electric lamp a brake wheel
caused to revolve by the movement of the carbons subject to the pressure of a
brake block mounted on a lever, which, by the action of regulating solenoids or
electro-magnets when the resistance of the arc is excessive is brought against a
stop and thus moved so as to release the brake, substantially as described.
Dated this 20th day of April 1893.
ABEL & IMRAY,
Agents for the Applicant.