Improved Cut-out Apparatus for Automatically Disconnecting Incan- descence Lamps having Filaments of Secondary Conductivity.
Year: 1899

page_text: Date of Application, 21st June, 1899-Accepted, 25th Nov., 1899
[Communicated from abroad by The Vereinigte ELECTRICITÄTS ACTIEN GESELL-
SCHAFT, of No. 16, Munkas Uteza, Budapest, Hungary, Manufacturers.]
Improved Cut-out Apparatus for Automatically Disconnecting Incan-
descence Lamps having Filaments of Secondary Conductivity.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of the Agency for Foreign
Patent Solicitors, of 322, High Holborn, in the County of Middlesex, 6, Lord
Street, Liverpool, and 6, Bank Street, Manchester, both in the County of Lan-
caster, and Lower Temple Street, Birmingham, in the County of Warwick,
Civil Engineer, do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:—
In electrical lamps with incandescent bodies of conductors of the second class
the illuminating current itself is generally used for the heating and conse-
quently rendering conductive of this incandescent body; the heating body,
consisting of good conductors, is cut out of the circuit by means of an automatic
device as soon as the light-giving body is rendered incandescent; if the light
disappears in consequence of the incandescent body being destroyed or cut out,
the good conductor is placed in circuit again.
There are considerable drawbacks in practice attached to this temporary inter-
polation of the heating body in the supply circuit of the lamp when the
conductivity of the filament is permanently or periodically destroyed, especially
in those lighting systems in which a control of all the separate lamps is impos-
sible, or in which the single lamps cannot be cut out: in these cases, if the
incandescent lamp breaks, for example, the current cannot reach the automatic
interrupting device and thus the good conductor continually keeps the lamp in
circuit. There is thus unnecessary consumption of current, the heating body is
destroyed in a short time and there is even danger of fire from the lamp in
consequence of the great evolution of heat.
The present invention is intended to do away with all these disadvantages
by means of an apparatus which after the lapse of a previously determined
time cuts the lamp out of circuit: this period or the time during which the.
heating body remains in circuit is so fixed as to avoid entirely or almost
entirely the aforesaid drawbacks.
The apparatus forming the object of the present invention is illustrated in
several constructional modifications in the accompanying drawing:—
Figure 1 is a diagram of the general arrangement of the apparatus.
Figure 2 is a vertical central section of one constructional form.
Figure 3 is a perspective view of another constructional form.
Figure 4 is a vertical section of the apparatus illustrated in Figure 3.
Figure 5 is an elevation.
Figure 6 a vertical section, and
TA
ation of anothan nonsturrational form

page_text: Figures 8 and 9 illustrate in horizontal section another modification of the
invention.
In incandescent lamps with conductors of the second class, the, heating up
of the light giving body is effected by means of heating devices operated by
the lighting current itself. For this purpose the circuit of each lamp is
.divided into two branches, in one of which is placed the light-giving body f
and a solenoid k while in the other branch a cut-out o operated by the solenoid k
is arranged; this cut-out is normally in such a position that the heating body H
is inserted in the line conductor.
If the current is now allowed to pass through the lamp, it flows first through
the branch of the circuit in which there is the least resistance, that is to say,
through the branch in which is placed the good conducting heating body H, which
hereby becomes red-hot; this heats the illuminating body 7, whereupon this
also becomes conducting. As soon as this occurs, the current flows through
the first branch, whereby the solenoid receives current and, by attracting the
armature, actuates the cut-out o which now automatically cuts-out the second
branch. It is obvious that if, for any reason, the light-giving body f is
destroyed the heating body H would remain interpolated in the circuit, if
precautions such as form the object of the present invention were not taken to
prevent it.
-
As shown in Figure 1 the cutting-out device S is interpolated in the circuit
of the heating body H which cuts the heating body out of circuit a certain time
after the lamp has been interpolated therein.
The simplest form of this apparatus is illustrated in Figure 2.
One connecting wire of the circuit of the heating body H is passed through
the sleeve provided with a winding a; this conductor is formed inside the
socket of a wire g of easily fusible metal, which is connected on the one hand
with the circuit conductor of the heating body H and on the other hand with
one end of the coil a, the other end of which is in connection with the circuit
conductor of the heating body H, so that the metallic wire g and also the coil a
with the heating body are connected in series.
and
is melted
If the lamp is now switched on, the current flows through the wire
the coil a to the lamp and after a given time the fusible metal wire
by the heating action of the coil, and in this manner the circuit of the heating
body is interrupted.
In the modifications illustrated in Figures 3 and 4, the arrangement of the
sleeve and the coil a is the same as in Figure 2, except that the wire g
consists here of two parts which are conductingly connected with each other
by means of an easily fusible metallic or non-metallic body: the current of
the heating body H now flows through the coil a, melts the connecting body
or substance and the two parts of the wire g are separated from each other;
this separation can take place in different ways; in the modification illustrated
in the drawing one part of the fusible metal wire g is connected with the end
of the spiral spring which draws this part of the wire out of and thus
interrupts the circuit.
In the modifications illustrated in Figures 5, 6 and 7 there are no coils a and
the current is only conducted through a wire g of easily fusible metal, which
wire is passed through the sleeve h placed in a special socket i. Both parts have
longitudinal slots on their circumference and can be twisted with regard to
each other so that the slots correspond and air freely enters into the inner
envelope; they can, however, be so placed that all the parts of the surface of
its casing cover the aforesaid slots so that air cannot get into the sleeve h.
If the slots are covered up in this manner, that is, to shut off the entrance
of air to the wires g, then the latter will melt more quickly than if the air
could freely enter through the sleeves; consequently the commencement of
fusing of the wire g can be determined or regulated by giving the apparatus
suitable dimensions,

page_text: The herein before described constructions of the cutting out apparatus have,
however, still the drawback that the interruption of the current after the fusing
of the wire gis permanent, that is, the apparatus after one operation is useless
for further employment and must be renewed.
This drawback is completely obviated in the construction illustrated in
Figures 8 and 9.
In this arrangement the circuit is only provisionally interrupted and can be
closed again each time by actuating a contact lever.
The coil a is in this case arranged under a vessel e enclosing a fluid or gas,
said vessel being closed by a cover m of some elastic material; this cover is
hinged to a single arm contact lever the free end of which has a contact piece ",
whilst the other end is so connected with a spring that this latter can main-
tain the lever in a raised position. Under normal conditions the circuit is
closed by the contact piece and the contact w of the apparatus. The current
flows along the conducting lines through the coil a the contact v, w, the lever r
the spring and the tripod y (made of conducting material) to the heating
body H.
According to the measure in which the coil a heats the fluid or gas in the
vessel the elastic cover (membrane) is raised by the fluid expanding, which
causes the lever to lift up the contact piece from w and thus interrupt the
current after this the fluid cools and is reduced to its original volume; by
pressing down the lever r the contact between , w is again restored and conse-
quently the circuit is closed.
As the resistance of the heating body H is not, as a rule, so great that it could
be joined immediately in the conducting lines, part of the tension is allowed
to be absorbed by a previously connected resistance.
This resistance can he advantageously replaced by the above mentioned
winding of the cutting-out apparatus so that its arrangement adds neither to
the complexity nor raises the cost of installation of the lamp.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, as communicated
to me by my foreign correspondents, I declare that what I claim is:
1. An improved connecting and disconnecting device for the heating bodies
of electric lamps having incandescence filaments of secondary conductivity con-
sisting of a conductor placed in the current circuit in series with the said
heated body which conductor can be altered in temperature by the current flow
and thereby varied from its normal condition; so that by means of the said
variation the solid fluid or gaseous cut-out is caused to interrupt the current
passing through the said heating body, substantially as described.
2. A constructional modification of the apparatus set forth in Claim 1, in
which by means of the heating produced by the current flow in a spiral inserted
in series in the current circuit of the heating body H at a temperature corre-
sponding to one of its dimensions a metallic wire g will melt and thereby
interrupt the current passing through it.
3. A constructional modification of the device characterized in Claim 1 in
which a coil a inserted in series in the current circuit of the heating body H
and composed of two parts connected by means of an easily fusible material
is temporarily separated through the heat generated and the consequent melting
of the connecting material and thereby the current is interrupted in the metal
wire g.
4. A constructional modification of the device set forth in Claim 1 in which
a metal wire is placed in two sleeves h, adjustable one with regard to the
other, and provided with apertures for the inlet of air, said wire being this
adjustable to fuse at variable periods of time and thereby to interrupt the
current circuit through it.
5. A constructional modification of the device set forth in Claim 1 in which

page_text: the heat developed in a winding a interpolated in series in the current circuit.
of the heating body H acts on a fluid or gas (enclosed in a vessel e) increased
in volume by the heat generated and by this increase in volume the contact
pieces, are separated and thereby the circuit of the heating body is
broken.
W. P. THOMPSON & Co.,
322, High Holborn, London, W.C., Patents Agents for the Applicant.