IMPROVEMENTS IN ELECTRIC LAMPS
Year: 1880

page_text: "
PROVISIONAL SPECIFICATION left by the said Gustavus Palmer Harding at
the Office of the Commissioners of Patents on the 15th October 1880.
GUSTAVUS PALMER HARDING, of 88, Jermyn Street, Piccadilly, London.
IMPROVEMENTS IN ELECTRIC LAMPS."
This Invention of improvements in electric lamps relates to the kind of lamp
where the upper carbon descends by gravity, and consists in the means by which
this carbon is regulated to fall as required.
For this purpose the carbon is held by two opposite cams, or in one case by the
action of four cams. In the more simple form the two cams are composed of two
eccentrics, both being hung upon an arm pivotted to move with the eccentric
bearing; these arms have each a stop to prevent them closing too tightly upon the
carbons, and each has a spring at the back to regulate the pressure of the cams
upon the carbon. The eccentrics have two connecting rods at another point different
from the eccentric centres; these rods are attached to the armature of a magnet.
The action of the apparatus is as follows:-The suitable connections being made
for the magnet, and the upper carbon being placed between the cams in a vertical
position, and resting upon the lower carbon, the current passing into the lamp, and
no are being formed, in consequence of the proximity of the carbons, the surplus
current passes into the magnet, overcoming by its strength the resistance wire,
which, when the light is burning, prevents the current from following that course,
the current acting on the magnet resists the armature, and by the cams lifts the
upper carbon a given distance, and the arc is formed.
Assuming that the light is in action, and the carbons burning away when the
arc becomes too long, a portion of the current finding an easier road goes to the
magnet, the armature is attracted, the cams release their hold upon the carbon, and
Paris C21

page_text: the carbon falls gently by its own gravity; all the current then passes to the arc,
and so on.
The carbons may be held in tubes or grooved rollers, or in any usual manner,
and vertically or inclined, and the cams where they clasp the carbon may have
plane or grooved surfaces.
This form of apparatus also enables me to apply two carbons inclined upwards,
and diverging from the central vertical line drawn through the arc, so that the arc
forms the apex of an angle, the angle pointing downwards, and the two carbons
indefinitely prolonged from the arc upwards, according to their length.
By a change of the bobbins either a continuous or intermittent current can be
used.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Gustavus Palmer Harding in the Great Seal Patent Office on the
14th April 1881.
GUSTAVUS PALMER HARDING, of 88, Jermyn Street, Piccadilly, London.
"IMPROVEMENTS IN ELECTRIC LAMPS."
The object of this Invention is to assure the relative position of the electrodes
in electric lamps, utilizing the effect of gravity on the electrodes and diverted
portions of the current in connection with electro magnets.
In the Drawings several examples show the practical mode of putting my
Invention into practice.
Figure 1 is a front elevation; Figure 2, a side elevation; Figure 3, a diagram on
a small scale, representing another arrangement than that in Figures 1 and 2;
Figure 4, a diagram representing a third arrangement; Figure 5, a front elevation,
and Figure 6 side elevation of a fourth plan; Figure 7, front elevation of a fifth
arrangement; Figure 8, automatic shunt and resistance; Figure 9, a current
collector for top carbon; Figures 10 and 11, plan and end view of a sixth
arrangement; Figure 12, elevation of seventh plan.
In Figures 1 and 2,
a represents the derivation coils taking portion of current from main circuit.
b, the armature acting on the levers c, c, through them on the cams d, d, which
grip the carbon e; f, the cock on which the cams d swing.
Assuming that the lamp is at rest, and the carbon e not resting on the lower
carbon, not shown, directly connection is made from the machine to the lamp a
portion of the current goes through the magnets a, a, being the route of least
resistance, the armature b is attracted, and actuates the cams d, which open and
release the pressure on the carbon; the current now passing between the two
carbons the magnets become inactive, and the springs g, g, pull back the armature
and actuate the cams in the contrary direction, causing them to close and lift the
carbon a short distance and establish the arc.
Figures 3 and 4 show modifications of two above arrangements of cams sufficiently
described by the Drawings.
Figures 5 and 6 another arrangement, the armature being above the magnet; on
it are pivoted two arms h, h, angled as shown at h, and in contact with two rollers ¿
fixed to the outer hub j by the cross piece k. When the armature is attracted the
inclined planes impinge against the rollers and open, thereby releasing the carbon e
or carbon holder, if one is used, the carbon descends until it touches the lower
carbon, the current passes through it, the magnets become inactive, the armature b
is withdrawn by the spring g, which allows the arms to close, grip the carbon,
slightly lift it, and form the arc.
Figure 7 shows two carbons placed at an angle, and sliding freely down tubes
connected by levers m in connection with the armature b, the tubes being pivotted
at n; stop screws o adjust the distance at which the carbon shall fall. When the
armature is pulled up the carbons descend until they touch; as soon as this takes
place the armature is released, and the springs separate the carbons, and the arc is
formed.
In a modification of the above a third carbon is used to regulate the arc; it is
fixed and regulated by the set screw q. The carbon p serves to prevent the carbons
descending too far, the are being of a length regulated by the thickness of the
carbon p.
Figure 8, automatic shunt resistance, shows the employment of two electro
magnets actuating an armature b, which, if an accident happens to the lamp, is
attracted by the magnets a, a, and making contact with the butting screw ? shunts

page_text: the current into the resistance of iron wire 8, equivalent to the resistance of the
lamp, and prevents damage to the machine.
Figure 9 is a collector consisting of two rollers t fixed to outer tube, down which
slides the carbon holders; the collectors t, t, send the current directly to the carbons,
prevent sparking, and also act as a kind of break to the carbon holder or carbon.
Figures 10 and 11, an arrangement of rocking lever to grip the carbon, to which
no claim is made.
Figure 12 shows special arrangement with armature A, magnets B, cone piece C,
lifters D, outer tube E, inner tube or carbon holder F, carbon G.
The arrangement here shown works as follows:-The shunt magnets on becoming
active attract the armature A, cause the sides of lifters D to impinge against the
cone piece C, thereby releasing the carbon holder F, which descends with the top
carbon and makes contact with the lower one; the magnet becomes inactive, the
armature goes up by the action of the springs H, H, and the lifters D released from
cone piece C grip the carbon holder, and with it the carbon, raise it up, and thereby
establish the arc. Springs shown on the clutches D assist the action, and the
springs H bring the armature back with the strength, as adjusted by the adjusting
screws I, I.
Having now described and particularly set forth the nature of the said Invention,
and the manner of carrying the same into effect, I would have it understood that
what I claim is,―
First. The combination of parts described and shown in Figures 1 and 2, for the
purpose substantially as described.
Second. The modifications shown in Figures 3 and 4, for the purpose set forth.
Third. The arrangement shown and described in Figures 5 and 6, substantially
as described.
Fourth. The arrangement of the inclined carbons, and the mechanism to actuate
them, substantially as described and shown in Figure 7, either alone or in com-
bination with the vertical third carbon plate between the inclined carbons,
substantially as and for the purpose set forth.
Fifth. The automatic shunt resistance, substantially as shown in Figure 8.
Sixth. The collector, Figure 9, substantially as shown and described.
Seventh. In connection with a shunt inagnet worked by derivation from the
main current the combination of the cone piece, the clutches, the springs on the
clutches, and the adjusting nut and screw I acting on the springs H, substantially
as described for the purpose set forth.
In witness whereof, I, the said Gustavus Palmer Harding, have hereunto set
my hand and seal, this Thirteenth day of April, in the year of our Lord
One thousand eight hundred and eighty one.