An Improvement in the Manufacture of Globes and Shades for Electric and other Lamps.
Year: 1897

page_text: An Improvement in the Manufacture of Globes and Shades
for Electric and other Lamps.
I, FOREST WILLIAM DUNLAP, of 3, Tokenhouse Buildings, in the City of London,
Electrical Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention relates to the manufacture of globes and shades for electric, gas, and
other lamps and has for its object to impart light refracting qualities thereto.
The invention consists in making the globe or shade of a spirally coiled slender
rod of glass of round or other section drawn direct from the melting pot and after
being passed through a die or not, as may be required, wound upon a heated mandrel
whilst still plastic and at such a temperature that the closely juxtaposed convolutions
coalesce and become welded together so as to form a rigid structure possessing lens
like qualities adapted to refract and diffuse the light as may be required.
1007
An Improvement in the Manufacture of Globes and Shades
for Electric and other Lamps.
I, FOREST WILLIAM DUNLAP, of 3, Tokenhouse Buildings, in the City of London,
Electrical Engineer, 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 :-
My invention has for its object to impart to the globes and shades of the various
kinds and shapes now used with electric gas and oil lamps or lighting apparatus,
light refracting qualities whereby the light will be diffused equally in such manner
that a portion of the light radiated in the direction of maximum illumination will
compensate for any deficiency of illumination in other directions, whereby the
effective illuminating power of the light is increased.
Two typical examples of the invention are illustrated in the accompanying drawings
wherein Figure 1 represents a globe of a form suited to an electric are lamp or gas
lamp and Figure 2 a bi-conical gas light globe. It is to be understood however, that
the forms illustrated are inerely examples and that they may be varied as desired.
The invention consists in making the globe or shade, of a slender rod a of glass of
circular or other suitable section and of about two millimetres diameter coiled whilst
DO71

page_text: in a plastic state upon a heated mandrel, whereby the temperature of the glass is
inaintained at such a point that the closely juxtaposed convolutions a¹ a² a³ etc.
coalesce or become welded together, the extent to which they are so united being
just sufficient to constitute a rigid structure without materially impairing the lens-
like properties of the rod.
The plastic rod of glass would be drawn direct from the mass of glass in the
melting pot and to ensure uniformity of shape and diameter might be drawn through
a heated die if required, and, whether passed through a die or not, would whilst still
plastic be wound upon a mandrel of the form of the globe or shade to be made, the
mandrel being heated in any suitable manner.
Where the globe or shade, is of bulbous or such other shape that the mandrel could
not be withdrawn from the completed article if the latter were made of one continuous
spiral, the article may be made in two parts divided as at c c Figure 2, the two parts,
after being separately made, being juxtaposed and united by welding before the
blow-pipe flame. Or the mandrel might be constructed of sections so as to be
separately removable from the completed article.
The globe or shade would (if required) be provided with a suitable supporting
neck or rim which may be made as indicated in Fig. 2, like the remainder of the
article, of a spirally coiled rod; or it might be made plain and welded to the spirally
coiled portion. It is to be understood that the two portions of a globe or shade may
be made of differently coloured glass according to the effect to be produced.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what I
claim is :-
The manufacture of globes and shades of a rod of glass of suitable section, spirally
coiled while in the plastic state upon a heated mandrel, so that the juxtaposed con-
volutions become united and form a rigid structure possessing refractive qualities as
described.
Babad thin
1000
333 MA
August
ነጋሽ
A. M. & WM. CLARK,
Chartered Patent Agents, 53, Chancery Lane, London.