IMPROVEMENTS IN ELECTRIC LAMPS
Year: 1879

page_text: PROVISIONAL SPECIFICATION left by John Imray at the Office of the
Commissioners of Patents on the 30th January 1879.
JOHN IMRAY, of No. 20, Southampton Buildings, Chancery Lane, in the County
of Middlesex. " IMPROVEMENTS IN ELECTRIC LAMPS."
In electric lamps as ordinarily employed the carbons have to be replaced by fresh
carbons, and for this purpose the lamp has to be extinguished, provided with
carbons, and readjusted at frequent intervals. The object of my Invention is to
provide carbons for electric lamps in such form and with such movement that they
are capable of serving for considerably longer periods than ordinary carbons. For
this purpose
I make the carbons in the form of hollow cylinders or short tubes, and
give them a motion of rotation round their axes, and at the same time a.motion of
advance in the line of their axes. The voltaic are being formed at the lips of the
tubes the consumption of the carbon takes place in a helical direction round the
periphery of the cylinder and along it longitudinally, so that each tube furnishes a
length of carbon equivalent to the length of the screw thread which is the direction
of its consumption. The carbon cylinders are placed in sockets or chucks on
spindles which are screw threaded and work in threaded bearings, and these
spindles being caused to revolve by clockwork or other suitable motor, the required
rotating and advancing movement is imparted to the carbons. A single carbon
tube such as I have described may be employed as the terminal which is the
more rapidly consumed, the other terminal being simply a rod of carbon or of other
known kind. In that case the carbon tube which constitutes the one terminal may
have merely the one movement of rotation, the other terminal being mounted on a
slide and caused to move along the tube lengthwise, or the tube terminal may be
made to rotate and advance while the other terminal remains stationary. When
both terminals are tubes, they are mounted with their axes at right angles or other
suitable inclination to one another, so that the lips of the tubes are near one
another at one point of their respective peripheries, and both are caused to rotate
and advance, but that which is the more rapidly consumed is made to move more
rapidly than the other. The movements of the terminals are effected by suitable
gearing, which as stated above may be worked by clockwork or other suitable
motor. A convenient power for this purpose is the weight of the lamp itself with
its mechanism, the whole being mounted on a stationary frame or hinged thereto,
so that it has to descend a certain distance during the action of the lamp, the
descending weight producing the required motion. In order to regulate the
distance of those points of the terminals between which the voltaic arc is formed,
the electric current itself may be applied in the known manner by passing it

page_text: through a coil of an electromagnet or a thin metal strip, which expands or
contracts in length according to the strength of the electric current passed through
it, the armature of the magnet or the strip being connected to a detent or break,
which when the armature is too strongly attracted or when the strip is extended in
length by the passage of an excessive current, stops or retards the gearing that
gives the feed motion to the terminals. One arrangement for stopping or retarding
the feed mechanism is of the following description:-The descending weight or
spring that gives motion to the feed gear is arranged also to move forward a piston
in a cylinder containing liquid, or to press forwards a flexible diaphragm in a vessel
containing liquid. There is an outlet for this liquid fitted with a valve or plug
which is connected to the armature of the electromagnet or to the metal strip, so that
when the electric current passing through the coil of the magnet or strip is in
excess, the valve or plug is moved so as to throttle or close the outlet, thereby
retarding or arresting the movement of the feed gear; but when the electric
current is diminished the valve or plug made to open more or less the outlet, and
so permit the feed gear to work with more or less rapidity. Besides the arrange-
ment for the automatic adjustment of the feed motion I provide also means for
effecting automatic variation of the distance between the terminals in the following
manner: I mount one of the carbons or terminals on a rocking shaft transverse to
its axis, and connect an arm from the shaft to an armature or metal strip, so that
when there is excess of electricity the rocking shaft is caused to turn partly round
in opposition to a weight or spring, thereby moving the one terminal away from
the other, and when there is a decrease of electricity the rocking shaft is caused by
the weight or spring to turn partly round in the opposite direction, causing the one
.terminal to approach the other. There may be an electro-magnet and armature or
a metal strip for this adjustment of distance separate from that above mentioned
for regulating the feed movement, or the same electro-magnet and armature or
metal strip may be applied to effect both adjustments. For the electro-magnet and
armature the known arrangement of a coil with a moveable iron core may be
substituted.