Improvements in the Manufacture of Incandescing Electric Lamps
Year: 1899

page_text: Reprinted
as amended in accordance with the decision of the Chief Examiner
dated the 27th day of August 1901.
The Amendments are shown in italic type.
Date of Application, 10th Oct., 1899
Complete Specification Left, 10th July, 1900-Accepted, 6th Oct., 1900
66
PROVISIONAL SPECIFICATION.
*Improvements in the Manufacture of Incandescing Electric Lamps."
I, WILLIAM LAWRENCE VOELKER, of 38, Bernard Street, Russell Square, in the
County of London, Electrician, do hereby declare the nature of this invention
to be as follows:-
This invention relates to lamps for lighting by the transmission of an electric
current through a filamentous conductor, formed of carbon, or other highly
resistent substance and enclosed within a vacuous chamber; my object being to
provide against certain influences which tend to disintegrate the conductor; such
disintegration having the effect not only of curtailing the life of the filament, but
of diminishing the lighting power of the lamp by reason of the deposit which
takes place upon the internal surface of the enclosing chamber.
In carrying out my invention, I employ a filament of the well-known U type,
and I mount the same in a vacuous chamber formed of glass. This chamber
differs in form from that commonly employed and consists of a body portion,
which encloses the bend of the filament, and two extensions, which respectively
enclose the legs thereof. The filament is attached in the usual manner to the
leading-in wires, sealed in the extremities of the two extensions; the latter
being mounted in a socket common to both and adapted to fit a holder. Under
such circumstances, any current which might seek to pass directly from the
one leg to the other of the filament is intercepted by an air-space and two thick-
nesses of glass. It is to this tendency of the current to pass across from the
one leg of the filament to the other that I attribute most of the disintegration
which takes place in the structure of the filament; the destructive effect increas-
ing with the resistance offered by the filament according to the material whereof
it is composed. I have moreover observed that there is far less heating of the
leading-in wires. This may in part be attributable to the presence of a greater
mass of comparatively cool glass closely surrounding each wire.
To facilitate the installation of a filament in a vacuous chamber of the kind
above described I adopt the following course. I take a thin rod of glass bent
into the form of an elongated U and having its extreme ends turned outwards.
In these outwardly turned ends the leading-in wires are respectively fixed, and
the filament is then attached to the wires in the usual manner. With the aid
of this glass carrier, the filament with its leading-in wires may now be handled
with facility and safety; its legs being inserted in the extensions which form
portions of the chamber until the leading-in wires protrude beyond the
extremities thereof; the bend of the carrier seating at the same time at the point
of bifurcation of the two extensions. The larger or bulbous end of the chamber
is then partially closed, the chamber is exhausted and finally it is closed. The
U-shaped carrier may if desired be broken away and removed after the leading-in

page_text: wires have been fixed; but, if left in the lamp, its presence is scarcely per-
ceptible.
Although in the foregoing description I have referred to a filamentous con-
ductor of the ordinary U-shaped pattern, it will be obvious that the application
of my invention is not confined to filaments of that particular form.
65
COMPLETE SPECIFICATION (AMENDED).
Improvements in the Manufacture of Incandescing Electric Lamps."
'I, WILLIAM LAWRENCE VOELKER, formerly of 38, now of 42, Bernard Street,
Russell Square, in the County of London, Electrician, 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 lamps for lighting by the transmission of an electric
current through a filamentous conductor, formed of carbon or other highly
resistent substance and enclosed within a vacuous chamber; my object being to
provide against certain influences which tend to disintegrate the conductor;
such disintegration having the effect not only of curtailing the life of the
filament, but of diminishing the lighting power of the lamp by reason of the
deposit which takes place upon the internal surface of the enclosing chamber.
A lamp adapted for carrying my invention into effect is illustrated in Figs.. 1
and 2 of the accompanying drawings; the former being a longitudinal section,
whilst the latter is a transverse section on the line - (Fig. 1). In Fig. 3,
the filament and its carrier, although included in Fig. 1, are illustrated separately.
The lamp comprises a filament A of the well-known U-type, mounted in a
vacuous chamber B formed of glass. This chamber differs in form from that
commonly employed and consists of a body portion b, which encloses the bend
of the filament A, and two extensions b' b₁ which respectively enclose the legs
thereof the chamber being somewhat in the form of a pair of breeches. The
filament A is attached in the usual manner to leading-in wires CC sealed in the
extremities of the two extensions 6' 61; the latter being mounted in a socket D
common to both and adapted to fit a holder.
In working under conditions such as above described, any current which
might seek to pass directly from the one leg to the other of the filament is
intercepted by the air-space E and the two thicknesses of glass forming the
inner sides of the tubular extensions b¹. It is to this tendency of the current
to pass across from the one leg of the filament to the other that I attribute
most of the disintegration which takes place in the structure of the filament;
the destructive effect increasing with the resistance offered by the filament
according to the material whereof it is composed. I have, moreover, observed
that there is far less heating of the leading-in wires. This may in part be
attributable to the presence of a greater mass of comparatively cool glass closely
surrounding each wire.
To facilitate the installation of a filament in a vacuous chamber of the kind
above described, I adopt the device illustrated in Fig. 3. F is a thin rod of
glass bent into the form of an elongated U and having its extreme ends f f
turned outwards. In these outwardly-turned ends, the leading-in wires C C are

page_text: respectively fixed, and the filament A is then attached to the wires in the usual
manner. With the aid of this glass carrier F, the filament A with its leading-in
wires CC may now be handled with facility and safety; the filament so mounted
being introduced through the top of the bulb (an opening being left for the
purpose) and its legs being inserted in the extensions b b which form portions
of the chamber B, until the leading-in wires protrude beyond the extremities
thereof; the bend f' of the carrier 1 seating at the same time at the point of
bifurcation of the two extensions. The larger or bulbous end 6 of the chamber B
is then partially closed, the chamber is exhausted and finally it is closed. The U-
shaped carrier F may, if desired, be broken away and removed after the leading-
in wires have been fixed; but, if left in the lamp, its presence is scarcely per-
ceptible.
Although in the foregoing description I have referred to a filamentous con-
ductor of the ordinary U-shaped pattern, it will be obvious that the application
of my invention is not confined to filaments of that particular form.
I am aware that various attempts have been made to effect the object of my
invention by interposing something between the two legs of a filament to prevent
current passing between. Such attempts have failed either from the interposed
screen being of an ineffective kind, or of a form which could not be commercially
manufactured, or from other causes, but I wish it to be understood that I make no
general claim to interposing such a screen between the legs of a filament.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I claim:-
1. The herein described method of manufacturing incandescing electric lamps
consisting in forming a bulbous body with two extensions which project in the
same direction and have an air-space between them somewhat in the form of a
pair of breeches then introducing a loop-shaped filament so that the legs thereof
respectively occupy the said extensions and are sealed therein, and finally closing
the bulbous part of the chamber and exhausting the same, substantially as de-
scribed.
2. An electric incandescing lamp, comprising a vacuous chamber embracing
the bend of the filament, and formed with two extensions which project in the
same direction and have an air-space between them somewhat in the form
of a pair of breeches; each extension enclosing a leg of the filament and having
its extremity separately mounted in a socket common to both extensions, substan-
tially as described.
3. For use in mounting a filament in an electric lamp chamber of the character
herein described, a U-shaped carrier formed with laterally turned extremities
wherein are fixed the leading-in wires, substantially as set forth.
1
1000
Dated this 2nd day
1000
For the Applicant,
G. G. M. HARDINGHAM.
Chartered Patent Agent.
Clun House, Surrey Street, London, W.C..