Year: 1886

page_text: Date of Application, 3rd May, 1886.
Complete Left, 3rd Feb., 1887.
Complete Accepted, 4th Mar., 1887.
I THOMAS JOHN Handford of 50, Bedford Row in the County of Middlesex,
Patent Agent, do hereby declare the nature of this invention to be as follows:-
This invention relates to the use of incandescent electric lamps in series, when
currents of high electro-motive force are employed to supply such lamps.
When lamps are so used, if the carbon filament of one of them breaks, one of two
things will occur.
Usually as soon as the filament breaks so that the current cannot pass through it,
the high tension current springs across the vacuous space within the lamp globe from
one side of the carbon below the point of breakage, to the other side.
If the lamp is provided with an electro-magnetic cut-out device for closing circuit
around it on the breakage of circuit within it, such cut-out will evidently not act under
the conditions, and are therefore continues and follows down the carbon and
leading-in wires to _ glass stem of the lamp which being heated becomes a good
conductor of electricity, and the arc or current then passes through the glass to the
wires within the stem and so on down to the socket and to the cut-out device if one is
used so that these parts are all damaged or destroyed, the continuity of the series
circuit is finally broken, and all the other lamps are extinguished and remain so until
the broken one is replaced.
Means for stopping the are, when it occurs, before it leaves the lamp and at the same
time keeping the series circuit closed around the broken filament, form one part of
this invention.
This is accomplished by placing the wires so close together within the stem that
when the are reaches the point where they are so placed, the melted metal of the wires
will pass across from one to the other and such wires are thereby at once fused or

page_text: soldered together and good electrical connection is made between them so that the are
is at once stopped, and the circuit is closed by the connected wires around the broken
filament to all the other lamps in series.
In order to bring the wires close together they may be twisted together, one or both
of them being covered with a very thin insulation which may be of a carbonizable
material such as cotton, whose carbonization by the heat may assist in making
electrical connection between the wires; or the wires may be placed, insulated from
each other, in any suitable wrapping or binding, such for example as a small tube of
fusible metal which will melt and assist in the soldering; or they may be run through
a double glass tube, the thin partition of glass insulating them from each other, in
which case the soldering occurs just at the top of the tube where the wires are close
together. My foreign correspondent does not claim the invention of the double glass
tube for this purpose, since he believes this specific device to have been invented by
another.
Sometimes however, when the carbon filament breaks, the arc does not form across
it. As above stated an electro-magnetic cut-out may be provided for each lamp
which will act to close a shunt around it under such circumstances.
My foreign correspondent, however, prefers to employ a simple device by which the
expense and inconvenience of the cut-out mechanism are obviated and this contingency
of the non-formation of the arc as well as that before explained is provided for in the
construction of the lamp itself. The second part of the invention relates to this device
which consists in joining the wires at the point where they are in soldering proximity
to each other, by placing upon and across them a small quantity of a material of such
resistance that practically no current will pass across it so long as there is a circuit
within the lamp, but that with the increased difference of the potential which arises at
this point when the filament is broken and the arc does not form, current will be
conveyed across and an are will be started by which the wires will be fused together
as before described. Thus a simple cut-out is provided within the lamp itself, which
will act to maintain the circuit whenever the filament breaks, whether the are across
the filament is formed or not.
With this device it is preferred to use the double glass tube before described upon
the top of which the material is placed in such manner as to connect the wires
together.
The preferred material is a mixture of a pulverized conducting substance with a
sticky or glutinuous non-conducting substance. Good results are obtained with a
mixture of peroxide of lead and mucilage which may be diluted with water so that it
can be applied with a brush. By using the proper proportions of conducting and non-
conducting substances, the proper resistance is given to the mixture so that with the
usual lamp current or when the arc across the filament is in progress, practically no
current will be conveyed but when there is no circuit of either kind within the lamp,
current will pass, the material will be volatilized, the arc will be started, and the wires
will be fused together.
THS. J. HANDFORD,
50, Bedford Row, London, W.C.

page_text: COMPLETE SPECIFICATION.
Improvements in and relating to Incandescent Electric Lamps.
I THOMAS JOHN HANDFORD of 50 Bedford Row in the County of Middlesex, Patent
Agent 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 the use of incandescent electric lamps in series when
currents of high electro motive force are employed to supply such lamps.
When lamps are so used, if the carbon filament of one of them breaks, one of two
things will occur.
Usually as soon as the filament breaks so that the current cannot pass through it,
the high tension current springs across the vacuous space within the lamp globe from
one side of the carbon below the point of breakage, to the other side.
If the lamp is provided with an electro-magnetic cut-out device for closing circuit
around it on the breaking of circuit within it, such cut out will evidently not act under
these conditions, and the are therefore continues and follows down the carbon and
leading in wires to the glass stem of the lamp which being heated becomes a good
conductor of electricity, and the are or current then passes through the glass to the
wires within the stem and so on down to the socket, and to the cut out device if one
is used, so that these parts are all damaged or destroyed, the continuity of the series
circuit is finally broken, and all the other lamps are extinguished and remain so until
the broken one is replaced.
Means for stopping the arc, when it occurs, before it, leaves the lamp and at the
same time keeping the series circuit closed around the broken filament, form one part
of this invention.
This is accomplished by placing the wires so close together within the stem that
when the arc reaches the point where they are so placed, the melted metal of the wires
will pass across from one to the other, and such wires are thereby at once fused or
soldered together and good electrical connection is made between them, so that the
are is at once stopped, and the circuit is closed by the connected wires around the
broken filament to all the other lamps in series.
In order to bring the wires close together they may be twisted together, one or both
of them being covered with a very thin insulation, which may be of a carbonizable
material such as cotton, whose carbonization by the heat may assist in making
electrical connection between the wires; or the wires may be placed, insulated from
each other, in a small tube of fusible metal which will melt and assist in the soldering;
or (as an equivalent for the metal tube) in any suitable wrapping or binding, or they
may be run through a double glass tube, the thin partition of glass insulating them from
each other, in which case the soldering occurs just at the top of the tube where the
wires are close together. My foreign correspondent does not, however, claim the
invention of the double glass tube for this purpose since he believes this specific device

page_text: to have been invented by another-viz. William Holzer of Harrison, New Jersey,
United States of America.
it.
Sometimes, however, when the carbon filament breaks, the arc does not form across
As above stated an electro-magnetic cut out may be provided for each lamp which
will act to close a shunt around it under such circunistances.
My said foreign correspondent, however, prefers to employ a simple device by which
the expense and inconvenience of the cut out mechanism are obviated and this con-
tingency of the non-formation of the arc as well as that before explained is provided
for in the construction of the lamp itself. The second part of the invention relates to
this device which consists in joining the wires at the point where they are in soldering
proximity to each other, by placing upon and across them a small quantity of a
material of such resistance that practically no current will pass across it so long as
there is a circuit within the lamp, but that with the increased difference of potential
which arises at this point when the filament is broken and the arc does not form,
current will be conveyed across and an are will be started by which the wires will be
fused together as before described. Thus a simple cut out is provided within the lamp
itself, which will act to maintain the circuit whenever the filament breaks, whether the
are across the filament is formed or not.
With this device it is preferred to use the double glass tube hereinbefore described,
upon the top of which the inaterial is placed in such manner as to connect the wires
together, although obviously the material may be placed on the wires without the
employment of such tube, the said wires being in this latter case twisted together and
one or both of them covered with a very thin insulation of cotton or other carbonizable
substance as herein before described, which insulation is removed at the part where the
material for joining the wires is to be applied.
The preferred material is a mixture of a pulverized conducting substance with a
sticky or glutinous non-conducting substance. Good results are obtained with a
mixture of peroxide of lead and mucilage which may be diluted with water so that it
can be applied with a brush. By using the proper proportions of conducting and
non-conducting substances, the proper resistance is given to the mixture so that with
the usual lamp current or when the arc across the filaments is in progress, practically
no current will be conveyed but when there is no circuit of either kind within the
lamp, current will pass, the material will be volatilized, the arc will be started, and the
wires will be fused together.
In the accompanying drawing:
Figures 1, 2, 3, 4 and 5 relate to the first part of the invention.
A is the enclosing globe, B the stem or wire support, C the carbon filament and a a
are the leading in wires of an incandescent electric lamp, such wires being sealed in
the stem at b.
As shown in figure 2, the wires a a are twisted together within the stem, they being
covered with a thin insulation c (figure 3) which may be cotton or other carbonizable
material. Figure 4 shows the stem of the lamp after an arc across the filament has
been formed and finally broken. Such arc first starts across the filament upon the
breaking of the carbon, and it continues down the filament and the wires a a destroying
the wires, and through the heated glass at 6 down into the stem until it reaches the
point where the twisting of the wires brings them into soldering proximity. Here the
arc is once stopped because a drop d of melted metal passes across from one wire to
the other and fuses or solders the two together forming a complete short-circuit
around the filament.
Instead of twisting the wires together they may be simply placed side by side and
held together by a tube or by any suitable wrapping or binding. In figure 5 a tube e
of lead, tin or other readily fusible metal is placed around the insulated wires which
will be fused by the heat of the are and assist in joining the wires together.
With the lamp just described, electro-magnetic cut outs have to be provided in
order that the lamp may be cut out and the series circuit continued, if the arc does
not form across the filament when it is broken.
This is shown in figure 1. D is an electro-magnet in a shunt 3, 4, from the series

page_text: circuit 1, 2 and E is its spring retracted armature in another shunt 5, 6, which is
made and broken at contact; g is a locking device. It is evident that if the carbon
breaks and no are forms, the magnet D will be energized, and the armature E will
close circuit at and be held by catch y until the lamp is replaced by a new one,
when the catch may be withdrawn and the armature released. Any suitable number
of lamps may of course be placed in series.
By the arrangement illustrated in figures 6, 7, 8 and 9 these electro-magnetic cut
outs are dispensed with. The parts of the lamp are designated by the same letters as
before. F is a double glass tube, that is one having two perforations hh. The wires a a,
which in this case do not have the insulation c, are passed through these perforations,
being thus brought close together but insulated from each other by the thin wall of
glass between them. At the top of the tube is placed upon the wires the mass of
material which may be a mixture of peroxide of lead and inucilage or other mixture
having the characteristics above set forth-that is, it is of such resistance that when
the lamp is in use or when there is an arc across the filament practically no current
will pass across it; but when the difference of potential rises at the points where this
material is placed, by reason of there being no circuit either around or across the
filament, current will pass across such material, it will be volatilized an arc will start
at this point and the wires will be soldered together as before, andas seen as in
figure 9.
"If, however, the arc does form when the carbon breaks, the action is the same as
in the first described arrangement, such are soldering the wires together when it
reaches k.
The wires where they are brought together below the tube are preferably covered
with shellac or other thin but high insulation, to prevent an arc from ever forming at
this point.
The material k, may be applied with a fine brush inserted in the stem after the glass
parts of the lamp are completed.
Figure 6 shows lamps such as just described connected in series without any
electro-magnetic cut out devices which, as stated, are unnecessary with these lamps.
Having now particularly described and ascertained the nature of my said invention,
and in what manner the same is to be performed, I declare that what I claim is :—
1. Placing the leading in wires of an incandescent electric lamp in such close
proximity within the stem of the lamp that they will be fused or soldered together by
the passage of an arc between them.
2. Joining the leading in wires by a connection of such resistance that practically
no current will be conveyed by it so long as a circuit exists within the lamp, but that
current will pass when circuit is broken within the lamp whereby an arc will be formed
between the wires and the wires fused or soldered together.
THS. J. HANDFORD,
50, Bedford Row, London, W.C.