Improvements in Glass Lenses or Light-projectors for Street and other Lamps.
Year: 1891

page_text: Date of Application, 14th Mar., 1891
Complete Specification Left, 14th Dec., 1891-Accepted, 16th Jan., 1892
PROVISIONAL SPECIFICATION.
Improvements in Glass Lenses or Light-projectors for Street and
other Lamps.
I, AUGUSTE NIEUWENHUYS of 2 Rue de l'Activité, Brussels, Belgium,
Engineer, do hereby declare the nature of this invention to be as follows:-
In a former Patent I described a construction of glass lenses or light-projectors
for street and other lamps, in which these were constructed as inverted truncated
cones surrounding the lower part of the lamp, the sides of such cones being formed
as bi-convex lenses, whereby the light of the lamp was thrown in a more or less
concentrated manner upon the road or floor in immediate proximity to the lamp.
According to my present invention, instead of constructing such lenses or
projectors of a bi-convex form, I construct them as plano-convex lenses, that is to
say, the face presented to the lamp burner being made a compound plane surface,
while the outer surface is made convex. By this construction, while still obtaining
an effective distribution of the light, the weight of the projector is reduced to
about one half, and in addition, the manufacture is greatly facilitated.
On the accompanying drawings are shewn various forms of such projector. In
the form shewn in vertical section and sectional plan at Figs. 1 and 2, the inner
surface of the projector may be considered as constituted by an infinite number of
small planes, forming in sectional plan a polygon having an infinite number of
sides, that is to say, a circle; the inclination or conicity of such surface may be
made greater or less, according as the distribution of the light is required to be
more or less concentrated.
I find however that a better distribution of light is obtained by forming the
inner surface with a definitely polygonal horizontal -ection; Figs. 3 and 4 shew a
vertical section and sectional plan of a construction in which the inner surface is of
a hexagonal pyramidal form. The horizontal section might also be made triangular,
In order still further to
square, pentagonal, or of any other polygonal form.
lighten the projector, the inner surface may be made more or less concave in the
vertical section, as at Figs. 5 and 6, the sectional plan being still of a polygonal
form. Or instead of this, the lightening of the projector may be effected by
forming the outer surface of a compound lenticular form, while maintaining the
inner surface of a pyramidal form as at Figs. 7 and 8.
J
Dated this 14th day of March 1891.
ABEL & IMRAY,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Glass Lenses or Light-projectors for Street and
other Lamps.
1, AUGUSTE NIEUWENHUYS of 2 Rue de l'Activité, Brussels, Belgium,
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 :-
In a former Patent I described a construction of glass lenses or light-projectors
for street and other lamps, in which these were constructed as inverted truncated
conca surrounding the lower part of the lamp, the sides of such cones being formed

page_text: as bi-convex lenses, whereby the light of the lamp was thrown in a more or
less concentrated manner upon the road or floor in immediate proximity to the
lamp.
According to my present invention, instead of constructing such lenses or
projectors of a bi-convex form, I construct them as plano-convex lenses, that is to
say, the face presented to the lamp burner being made a compound plane surface,
while the outer surface is made convex. By this construction, while still obtaining
an effective distribution of the light, the weight of the projector is reduced to
about one half, and in addition, the manufacture is greatly facilitated.
On the accompanying drawing and the drawings filed with my Provisional
Specification are shown various forms of such projectors. In the form shewn in
vertical section and sectional plan at Figs. 1 and 2, the inner surface of the projector
may be considered as constituted by an infinite number of small planes, forming in
sectional plan a polygon having an infinite number of sides, that is to say, a circle;
the inclination or conicity of such surface may be made greater or less, according
as the distribution of the light is required to be more or less concentrated.
I find however that a better distribution of light is obtained by forming the
inner surface with a definitely polygonal horizontal section; Figs. 3 and 4 shew a
vertical section and sectional plan of a construction in which the inner surface
is of a hexagonal pyramidal form. The horizontal section might also be made
triangular, square, pentagonal, or of any other polygonal form.
In order still further to lighten the projector, the inner surface may be made
more or less concave in the vertical section, as at Figs. 5 and 6, the sectional plan
being still of a polygonal form. Or instead of this, the lightening of the projector
may be effected by forming the outer surface of a compound lenticular form, while
maintaining the inner surface of a pyramidal form as at Figs. 7 and 8.
Figs. 9, 10 and 11 on the accompanying drawing shews a construction of projector
which at the same time constitutes the lantern. Fig. 9 shews a vertical section as
applied to a petroleum street lamp and Fig. 10 shews a sectional plan; Fig. 11
shews an elevation as applied to a gas street lamp. The annular light projector P
of lenticular section forms the body of the lantern, being secured in a suitable
metal framework A by means of which it is carried in a two-armed support B B
fixed to the upper end of the lamp-posts. The upper end of the lantern is closed
by crown with wind puzzle C for preventing the wind from extinguishing the lamp,
and at the lower end the framing has an internal ring F carrying two hinged
semicircular flaps M which open upwards for allowing the introduction of the oil
lamp, and which in closing down again, constitute the support for the latter which
rests with a rim R thereon. Any other arrangement for supporting the lamp may
be employed in connection with the annular lenticular lantern.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
1. Annular light projectors for street and other lamps constructed as plano-
convex lenses of a truncated conical form, the angular divergence of the lenses
being proportioned to the distance to which the light requires to be projected,
substantially as described with reference to Figs. 1 and 2 of the drawings.
so as to
2. In annular light projectors of the lenticular section, in particular those of
a truncated conical form, constructing the inner surface of the projector
con-titute a regular truncated pyramid so as to form plane face- of a number
suited to the diameter of the projector, and thus constitute plano-convex lenses
of very clear refracting power, substantially as described with reference to Figs. 3
to 8 of the drawings.
3. The use of annular lenticular light projectors such as are referred to in the
preceding claims, for constituting at the same time the outer casing of a lantern,
the light projector being for this purpose combined with a suitable metal framing

page_text: and devices for fixing the same to a support and for containing the illuminating
medium, substantially as described with reference to Fig. 9, 10 and 11 of the
drawings.
Daid thin with d...
ABEL & IMRAY,
Agents for the Applicant.