Year: 1886

page_text: We, ROBERT DICK, manufacturer and RANKIN KENNEDY, Electrical Engineer,
both of the Electric Lamp Works, 115 Woodside Road, Glasgow, Lanarkshire, do
hereby declare the nature of our Invention and in what manner the same is to be
performed to be particularly described and ascertained in and by the following
statement in writing, reference being had to the accompanying sheet of Drawings
and to the letters and figures marked thereon, that is to say -
Our invention has reference to improvements in the regulating mechanism of
that class of arc lamps in which a clutch actuated by an electro-magnet through
which the electric current passes is used to regulate the position of the upper
carbon holder and carbon, the lower carbon or electrode remaining fixed.
And in order that the nature and novelty of our said invention, and the mode of
carrying the same into effect or practice may be properly understood, we have
hereunto appended an explanatory Sheet of Drawings showing our improvements
applied to an arc lamp. In these Drawings the same reference letters indicate the
same parts in all the Figures where shown.
In these Drawings, Figures 1 and 2 represent a front and side elevation
respectively, and Figure 3 a plan corresponding to Figure 1 of one arrangement of
are lamp complete showing our improvements applied thereto for regulating the
position of the upper carbon holder and positive carbon electrode. While Figure 4
is a sectional elevation corresponding to Figure 1, of the upper part of the lamp
showing our improved regulating mechanism applied thereto."
Referring to these Drawings our improvements consist in mounting a spring A
on the longer arm of the "washer" clutch B used in this class of arc lamp. This
spring A presses against the positive carbon holder C, and has for its object to
dispense with the usual "dash pot," by preventing any sudden fall of the positive
carbon holder C, and its electrode while it is being released by the clutch B. The
tension or pressure of this spring A on the carbon holder C is regulated by the
thumb screw a, so that when the carbon holder is released by the lowering of
the clutch B it slides slowly down. The clutch B is actuated by a new or improved
swivelling armature D and electro-magnet E through which the electric current
passes. This electro-magnet E is preferably secured at its upper end to a
bracket E¹ mounted on the lamp holder E2, and is constructed of rectangular
Din 077

page_text: shape, preferably of soft iron, and on two of its sides or cores copper or other
wires are wound as hereinafter explained, while the lower and upper ends of the
magnet form the South and North Poles S and N respectively. The new or
improved armature D consists of a straight bar, preferably of soft iron, with bent
or segmental ends, or of an S shape, and is mounted on a central fulcrume d,
between the coils and the north and south poles to a hanging bracket a screwed
to the North pole above. The upper hooked end of the clutch B is attached to the
armature D by means of a cord b, or equivalent device, passing over a guide
pulley b¹, mounted on a bracket 62 secured to the holder E2. The electro-magnet E
is wound with a thick copper wire e, through which passes the main electric
current from the outer circuit through the positive terminal F. It is also wound
with a fine or thinner wire e¹ and through it passes a small current which is
shunted or short circuited across the arc, from the positive terminal F, to the
negative terminal F¹. The greater the distance which the positive and negative
carbon electrodes are apart, the stronger will be the current which will pass
through the shunt wire e¹ and therefore less through the thick wire e and inner
circuit of the lamp.
By this differential action an arc distance is found for the electrodes to be apart,
generally about one eighth of an inch, at which the pulling apart by the current
passing through the thick wire e is counterbalanced by that passing through the
thin wire e, and this would be the position of the electrodes in their normal
working state. As the positive electrode is consumed slowly away the shunt
current passing through the fine wire still lessens or checks that passing through
the thick wire, and allows the armature to fall back until the point of the screw a³,
on the clutch B comes in contact with the frame of the lamp at G, and releases
the carbon holder C, when the magnet E immediately causes the armature D to
again raise the clutch B and the carbon holder to strike and maintain the arc
distance.
When the lamp is not in action the position of the armature and clutch are as
shown in the Drawings, the armature lying at an angle across the magnet, and
varies from this to the position shown in dotted lines in Figure 4, when working
and maintaining the arc.
When the lamp is placed in circuit the current enters by the positive terminal F,
then through the thick wire of the electro-magnet, and from their passes through
the body of the lamp and carbon holder C and electrodes, and passes out by the
negative terminal F¹, all as indicated by the arrows in Figure 1. While the
current passes through the electromagnet it magnetises it, and so causes an attractive
pull on the armature in proportion to the strength of the current which tends to
swing its straight portion round into a position parallel to the magnet as shown in
dotted lines in Figure 4.
This motion of the armature D pulls up the string b and lifts the clutch B which
pulls up the carbon holder C, and positive electrode from resting on the negative
electrode and thus "strikes the arc."
The carbon holder C slides slowly down against the spring A until the carbons
are at the proper distance apart for a proper are light, when the currents passing
through the main and shunt wires on the clectromagnet will again balance each
other, and the clutch B will thus retain the carbon holder C until again released
by the consuming away of the positive carbon sending more current through the
shunt wire.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is:—
First. In electric arc lamps, the construction and use of a clutch B, with the
spring A, a, electro-magnet E, and oscillating armature, D, substantially as and
for the purposes herein described in reference to and shown in the accompanying
Drawings.

page_text: Second. The construction of an electro-magnet E, with oscillating armature D,
for adjusting or regulating the arc or distance apart of the electrodes in electric
arc lamps, substantially as herein described in reference to and shown in the
accompanying Drawings.
Third. The construction of a clutch B, with regulating spring A, a, for raising
and lowering the carbon holder C, and adjusting the arc or distance apart of the
Electrodes, in Electric arc lamps, substantially as herein described, in reference to
and shown in the accompanying Drawings.