release and alongside the sinking of the Lusitania, the evacuation at Gallipoli,
the introduction of ‘phosgene’ on the Western Front and the battles of
Verdun, Jutland and the Somme, Robert worked on two processes; for
manufacturing, and then exhausting and sealing lamps. Patent applications
were prepared in Germany by 24 October 1916 with Robert as Assignor to
the GEC company of New York,
53 but a variation on the patent, improving
the sealing of the exhausted lamps, was later widely filed throughout Europe
and the U.S.A.
54 The distribution of these applications shows that the
improvements were internationally significant in terms of the manufacturing
of the lamps, leading to improved life-times, economies in effort and raw
material, and facilitating automated mass production. Robert’s first innovation addressed the efficient exhaustion of lamps
55 which up until then had
been achieved by first making an opening in the crown of the bulb, ‘welding’
a narrow glass exhaustion tube to it which was then sealed off by melting once
the lamp had been exhausted. This led to a ‘pip’ seal on the crown of the
bulb,
56 it also introduced a considerable number of steps into the exhaustion
process and wasted glass, for these tubes could only be used once or twice
before they were discarded. Robert’s innovation was to exhaust the lamp from
the base of the bulb rather than the crown.
Figures 14.4 and 14.5 show the drawings accompanying Robert’s original
patent application. ‘Figure 1’ in Fig. 14.4 illustrates a lamp prepared by
Robert’s method. The central stem, b, of the lamp supports the filament unit
and is flared at its base to facilitate its fusion to the wall of the bulb. The short
hooked ‘tubulature’, a, is the means by which the lamp interior is exhausted
and is formed from the glass of the stem alone using the apparatus drawn in
both plan and side views in ‘Fig. 2’ and ‘Fig. 3’ respectively of Fig. 14.4. To
form the tubulature, a stem was firstly secured in the ‘chuck’ of the device and
rotated, simultaneously warming the base with a gas torch. The chuck was
then stopped and a narrow blow pipe flame was used to heat up a small
circular portion of the stem wall just above the flare until it became ‘plastic’
and easily deformed. The lever f, pivoted adjacent to the chuck and carrying a
hooked, cylindrical, tapered, mandrel on its free end, was then swung into the
plastic glass creating the ‘tubulature’ shown in ‘Fig. 2.’ which hardened on
cooling. Bulbs were placed over the modified stems and fused to the flared
base to provide the lamps shown in Fig. 1. The tips of these ‘tubulatures’
were then broken and the modified lamps placed in the exhaustion/sealing
apparatus shown in Fig. 14.5 which Robert described as able to hold a
‘plurality’ of lamps. Evacuation of the chamber simultaneously evacuated the
lamp interior via the tubulatures leading to balanced pressures inside and
outside the bulb. This meant that the chamber could then be heated to near
14 Robert’s War 1914–1918
289
the introduction of ‘phosgene’ on the Western Front and the battles of
Verdun, Jutland and the Somme, Robert worked on two processes; for
manufacturing, and then exhausting and sealing lamps. Patent applications
were prepared in Germany by 24 October 1916 with Robert as Assignor to
the GEC company of New York,
53 but a variation on the patent, improving
the sealing of the exhausted lamps, was later widely filed throughout Europe
and the U.S.A.
54 The distribution of these applications shows that the
improvements were internationally significant in terms of the manufacturing
of the lamps, leading to improved life-times, economies in effort and raw
material, and facilitating automated mass production. Robert’s first innovation addressed the efficient exhaustion of lamps
55 which up until then had
been achieved by first making an opening in the crown of the bulb, ‘welding’
a narrow glass exhaustion tube to it which was then sealed off by melting once
the lamp had been exhausted. This led to a ‘pip’ seal on the crown of the
bulb,
56 it also introduced a considerable number of steps into the exhaustion
process and wasted glass, for these tubes could only be used once or twice
before they were discarded. Robert’s innovation was to exhaust the lamp from
the base of the bulb rather than the crown.
Figures 14.4 and 14.5 show the drawings accompanying Robert’s original
patent application. ‘Figure 1’ in Fig. 14.4 illustrates a lamp prepared by
Robert’s method. The central stem, b, of the lamp supports the filament unit
and is flared at its base to facilitate its fusion to the wall of the bulb. The short
hooked ‘tubulature’, a, is the means by which the lamp interior is exhausted
and is formed from the glass of the stem alone using the apparatus drawn in
both plan and side views in ‘Fig. 2’ and ‘Fig. 3’ respectively of Fig. 14.4. To
form the tubulature, a stem was firstly secured in the ‘chuck’ of the device and
rotated, simultaneously warming the base with a gas torch. The chuck was
then stopped and a narrow blow pipe flame was used to heat up a small
circular portion of the stem wall just above the flare until it became ‘plastic’
and easily deformed. The lever f, pivoted adjacent to the chuck and carrying a
hooked, cylindrical, tapered, mandrel on its free end, was then swung into the
plastic glass creating the ‘tubulature’ shown in ‘Fig. 2.’ which hardened on
cooling. Bulbs were placed over the modified stems and fused to the flared
base to provide the lamps shown in Fig. 1. The tips of these ‘tubulatures’
were then broken and the modified lamps placed in the exhaustion/sealing
apparatus shown in Fig. 14.5 which Robert described as able to hold a
‘plurality’ of lamps. Evacuation of the chamber simultaneously evacuated the
lamp interior via the tubulatures leading to balanced pressures inside and
outside the bulb. This meant that the chamber could then be heated to near
14 Robert’s War 1914–1918
289