Light Refracting and Magnifying Envelopes, Shades, and Globes for Gas and Oil Flames.
Year: 1897

page_text: Date of Application, 23rd Jan., 1897
Complete Specification Left, 23rd Nov., 1897-Accepted, 23rd Apr., 1898
PROVISIONAL SPECIFICATION.
Light Refracting and Magnifying Envelopes, Shades, and Globes
for Gas and Oil Flames.
We, FOREST WILLIAM DUNLAP and JOHN ROBERT QUAIN, both of 3, Tokenhouse
Buildings, in the City and County of London, Electrical Engineers, do hereby
declare the nature of this invention to be as follows:-
Our invention relates to light refracting and magnifying envelopes, shades, and
globes, for incandescent and other gas lights or oil lamps whereby to increase the
effective illuminating power of the light.
The invention consists of a cup, globe, shade, chimney, or other form of envelope
made of one or more closely wound spiral coils of glass rod or small circular or
prismatic section fashioned by coiling on a mandrel or otherwise into the required
form. The envelope may constitute the shade or globe itself and it would then
be provided with a neck, rim, or other means of supporting it upon a gallery or
holder.
To form an envelope of complete globular form it may be necessary to make two
hemispherical coils and to join them by fusing together the abutting ends or by
uniting them by means of cement, and the juxtaposed coils may also be united
throughout by cement. The envelope may be made of clear, frosted, or other glass
rod colourless or coloured, or of any combination thereof, according to the effect
to be produced.
100%
Light Refracting and Magnifying Envelopes, Shades, and Globes
for Gas and Oil Flames.
We, FOREST WILLIAM DUNLAP and JOHN ROBERT QUAIN, both of 3, Tokenhouse
Buildings, in the City and County of London, Electrical Engineers, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement:
Our invention relates to light refracting and magnifying envelopes, shades, and
globes more particularly for incandescent and other gas lights or oil lamps whereby
to increase the effective illuminating power of the light.
The invention consists of a cup, globe, shade, chimney, or other form of envelope

page_text: made of a closely wound spiral coil or coils of slender glass rod of circular or other
section fashioned by coiling on a mandrel or otherwise into the required form. The
envelope thus maue may be applied upon, or within, an ordinary cup shade or
globe of corresponding form which will act as a support for the spirally coiled
envelope or the latter may itself constitute wholly or partially the shade or globe
without any support and it would then be provided with a neck, rim, or other
means of supporting it upon a gallery or holder.
To form an envelope of complete globular form it may be necessary to make two
hemispherical coils and to join them by fusing together the abutting ends or by
uniting them by means of cement, and the juxtaposed coils may also be united
throughout by cement. The envelope may be made of glass rod colourless or
coloured, or of any combination thereof, according to the effect to be produced.
In the accompanying drawings forming part of this specification we have repre-
sented a few examples of light refracting envelopes formed of spirally coiled glass
rod, the envelopes being represented in some cases as applied upon a shade or
globe of corresponding form as a support. It is to be understood however that
the forms illustrated are merely examples and that they may be varied as desired.
Figure 1 shews a bi-conical shade formed of spirally coiled glass rod and suitable
for application around the chimney of an incandescent gas light. Figure 2 shews
an envelope of spirally coiled glass rod applied upon an ordinary gas globe.
Figure 3 shews similar envelopes applied to a glass cup and shade which would
in this case be made of clear glass instead of opal glass as usual. Figure 4 shews
a similar envelope applied about the bulbous part of a lamp chimney. In all these
figures only a portion of the spirally coiled envelope is represented, the outline
of the remainder being merely indicated by dotted lines.
In Figure 1 the shade is supposed to be formed of two separately formed
cones a a¹ of spirally coiled glass rod of circular section as shewn, partly broken
away at b, the coils being closely wound upon a suitable mandrel and the two cones
thus formed being united at the line 1-1 by fusing together the abutting ends
before the blow-pipe or by cement. The shade thus formed may be self-supporting
and be provided with a rim or neck c to fit a gallery or holder or it may be applied
around or within a clear glass shade of corresponding form as a support and to
which it may be çemented throughout.
In Figure 2 the envelope is formed of two hemispherical coils d d¹ and is repre-
sented as applied upon an ordinary gas globe of clear glass e, the two coils being
cemented together at the median line 2-2 and if necessary to the globe over its
whole surface.
It will be obvious that although described in reference to gas and other lights
these forms of envelope are equally well adapted for refracting and diffusing the
light from an electric arc.
In Figure the coil about an ordinary shade of clear glass g and the coil f¹
about an ordinary clear glass cup are each composed of a single coil of spirally
wound glass rod cemented to the shade or cup as the case may be. In each case
the coil may be applied upon the inner, instead of the outer, surface of the shade
or cup.
In Figure 4 two similar hemispherical, or approximately hemispherical, coils i¹
are shewn as applied about the bulbous portion of a lamp chimney j, the two coils
being united at the median line 44 as above described.
It will be obvious that in all cases where the coil or coils are applied in connec-
tion with a globe, shade, or support of corresponding shape that the latter may be
fashioned by the ordinary process of glass-blowing and moulding so as to fit within
or upon a previously formed spiral coil or coils. The glass rod of which the coil
is made is in all cases supposed to be drawn direct from the melting pot, passed
through a heated die if necessary to produce the required sectional form and ensure
uniformity of diameter, and is coiled while still in a sufficiently plastic state about
a suitable mandrel.

page_text: Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, we declare that what
we claim is:-
:-
The manufacture of a light refracting and magnifying envelope, shade, or globe
for gas and other lights, of a closely wound spiral coil or coils of glass rod of
slender circular or other section substantially as specified.
Dated this 23rd day of November 1897
A. M. & WM. CLARK,
Chartered Patent Agents, 53, Chancery Lane, London.