IMPROVEMENTS IN THE MANUFACTURE OF INCANDESCENT ELECTRIC LAMPS
Year: 1883

page_text: LETTERS PATENT to John Richard Hutchinson Williamson of Great Russell
Street in the County of Middlesex and Ernst Böhm of Northampton
Street Clerkenwell in the County of Middlesex for an Invention of
"IMPROVEMENTS IN THE MANUFACTURE OF INCANDESCENT ELECTRIC LAMPS
"
PROVISIONAL SPECIFICATION left by the said John Richard Hutchinson
Williamson and Ernst Böhm at the Office of the Commissioners of Patents on
the 3rd January 1883.
JOHN RICHARD HUTCHINSON WILLIAMSON of Great Russell Street in the
County of Middlesex and ERNST BÖHм of Northampton Street Clerkenwell in
the County of Middlesex, "IMPROVEMENTS IN THE MANUFACTURE OF INCAN-
DESCENT ELECTRIC LAMPS
"
Our invention has reference to the manufacture of incandescent electric lamps
and its objects are, an improved mode of mounting the platinum wires or terminals
in the lamp globe or flask, an improved mode of securing the carbon filament or
electric bridge to the platinum wires, and generally to improve the manufacture
and appearance of the lamp. We effect the above objects as follows:-We take an
inverted T, or 1 shaped piece of glass, which we prefer to manufacture by
flattening out one end of a glass rod and then squeezing or folding up the flattened
out portion into an approximately cylindrical form at right angles to the rod.
Through the two arms respectively of this piece we pass the lower parts of the
two platinum wires, and this may conveniently be effected by melting the ends of
the two arms, and then manipulating the melted glass around the wires. The wires'
are thus held at their lower part by the arms of the 1 piece so that all liability to
turn or twist together with the carbon filament is prevented. In order to secure
the upper parts of the wires and to hermetically seal the neck of the globe in such
a way as to avoid the leakage which is frequently caused owing to the unequal
contraction or expansion of the glass and metal we form a disc upon the upper end
of the glass rod above described by melting and flaitening and preferably before
the wires are secured to the 1 piece as above explained and we connect the upper
parts of the wires to the disc by melting a portion of the edge of the latter and

page_text: manipulating it around the wires. We then insert the glass rod, with the wires
secured thereto at the upper and lower parts as above described and with the
carbon filament secured to the wires, into the neck of the globe and unite the glass
disc to the top of the neck by a glass-blower's joint, after which the lamp is
exhausted in the usual way. For convenience of manipulation a short glass rod
may be welded to the upper portion of the disc before described; this rod would be
cut off after the connection with the neck has been formed. For the purpose of
readily securing the ends of the carbon filament to the platinum wires we flatten
the ends of the wires and drill a small hole through each into which holes we
insert the ends of the filament; we then apply a suitable cement to fix the parts
together. In order to reduce the capacity of the globe or flask relatively to the size
of the filament whereby the time occupied in exhausting the lamp is diminished we
reduce the diameter of the globe at the upper portion thus making it more pear
shaped and this has the further advantage of improving the appearance of the lamp.
The manner in which the diameter of the globo at the upper part may be reduced
is to submit this part of the globe after it has been made of the usual spheroidal
form, to alternate heating and gentle blowing whereby it becomes contracted, at the
same time retaining its circular form in horizontal section.
In the foregoing description we have considered the globe as being held in a
vertical position with the neck at the top.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Richard Hutchinson Williamson and Ernst Böhm in the
Great Seal Patent Office on the 2nd July 1883.
JOHN RICHARD HUTCHINSON WILLIAMSON of Great Russell Street in the
County of Middlesex, and ERNST Вöнч of Northampton Street Clerkenwell in
the County of Middlesex "IMPROVEMENTS IN THE MANUFACTURE OF INCAN-
DESCENT ELECTRIC LAMPS
"
Our invention has reference to the manufacture of incandescent electric lamps
and its objects are an improved mode of mounting the platinum wires or terminals
in the lamp globe or flask, an improved mode of securing the carbon filament or
electric bridge to the platinum wires, and generally to improve the manufacture
and appearance of the lamp. We effect the above objects as follows:-Wo take an
inverted Tor shaped piece of glass, and through the two arms respectively of
this piece we pass the lower parts of the two platinum wires and this may
conveniently be effected by melting the ends of the two arms, and then
manipulating the melted glass around the wires. The wires are thus held at
their lower part by the arms of the 1 piece so that all liability to turn or twist
together with the carbon filament is prevented. In order to secure the upper parts
of the wires and to hermetically seal the neck of the globe in such a way as to
avoid the leakage which is frequently caused owing to the unequal contraction or
expansion of the glass and metal we form a bar or disc upon the upper end of the
glass piece abovo described and we connect the upper parts of the wires to tho
bar or disc by melting a portion of the edge of the latter and manipulating it
around the wires. We then insert the glass piece with the wires secured thereto
at the upper and lower parts as above described, and with the carbon filament
secured to the wires, into the neck of the globe and unite the glass bar or disc to
the top of the neck by a glass blower's joint, after which the lamp is exhausted in
the usual way. For convenience of manipulation we weld a short glass rod to the
upper portion of the bar or disc before described; this rod would be cut or drawn
off after the connection with the neck has been formed.
The manner in which we prefer to manufacture the glass pieco for holding the
platinum wires as above described is as follows:-We take a glass rod such as that
shown at a in Figure 1 of the annexed drawings and by melting and flattening
out one end thereof and then squeezing or folding up the flattened out portion
into the form of a bar b we obtain the piece represented in Figure 2; or instead of
the bar b we may form a disc on the end of the rod. We then weld to the bar
(or disc) b a glass rod c Figure 3 for convenience of manipulation. We next
Hatten out the other end of the rod a and form therefrom a bar or cylinder d.
We thus obtain a piece of glass of the form seen in Figure 4. We connect the
platinum wires e e respectively to the two ends of the bars band d by melting the
ends of these bars and then manipulating the glass around the wires. After
having secured the carbon filament to the inner ends of the wires c e wo
introduce the glass piece with the wires and filament into the flask or globe
which may be such as is represented in elevation in Figure 5 and in plan in
Figure 6. The shape and size of the opening g in the next should be approximately
that of the bar (or disc) b. The bar bis then united to the neck by a glass-
blower's joint and the rod c is cut or drawn off after which the lamp is exhausted
in the usual way.
For the purpose of readily securing the ends of the carbon filainent in
incandescent lamps to the platinum wires we insert each end of the filament

page_text: through a hole in a flat portion of the platinum support and we then apply a
suitable cement to fix the parts together. Figure 4 illustrates this part of our
invention. The ends of the wires ce are flattened as seen at hh, a small hole is
drilled through each and into these holes the ends of the filament fare inserted;
the cement is then applied to fix the parts together.
In order to reduce the capacity of the globe or flask relatively to the size of the
filament whereby the time occupied in exhausting the lamp is diminished, we
reduce the diameter of the globe at the upper portion as seen at i Figure 5 thus
making it more pear shaped, and this has the further advantage of improving the
appearance of the lamp. The manner in which the diameter of the globe at the
upper part may be reduced is to submit this part i of the globe after it has been
mado of the usual spheroidal form to alternate heating and gentle blowing
whereby it becomes contracted at the same time retaining its circular form in
horizontal section. Figure 7 represents a complete lamp manufactured according
to our invention.
In the foregoing description we have considered the globe as being held in a
vertical position with the neck at the top.
Having now described the nature of our said invention and in what manner the
same is to be performed we declare that we claim as our "Improvements in the
manufacture of incandescent electric lamps
=
"'
First Connecting the platinum wires near their inner ends to the ends of a
shaped glass piece substantially as and for the purpose hereinbefore described.
Second-Connecting the platinum wires near their outer ends to a glass bar or
disc and then uniting this bar or disc to the neck of the flask or globe, substantially
as and for the purpose herein before described.
Third Securing the carbon filament by inserting each end thereof through a
hole in a flat portion of the platinum support and then cementing the parts
together, substantially as described.
In witness whereof I the said John Richard Hutchinson Williamson for
myself and on behalf of the said Ernst Böhm have hereunto set my hand
and seal this twenty seventh day of June One thousand eight hundred and
eighty three.