IM- PROVEMENTS IN TRANSLUCENT GRATINGS FOR COVERING HORIZONTAL, VERTICAL, OR OTHER OPENINGS OF CELLARS, OR OTHER CHAMBERS OR SPACES
Year: 1877

page_text: LETTERS PATENT to Andrew Ronald Nairne and James Waddell, in the
Employment of Messieurs Moses McCulloch and Company, Ironfounders, of
Glasgow, in the County of Lanark, North Britain, for the Invention of "IM-
PROVEMENTS IN TRANSLUCENT GRATINGS FOR COVERING HORIZONTAL, VERTICAL,
OR OTHER OPENINGS OF CELLARS, OR OTHER CHAMBERS OR SPACES."
Scaled the 8th September 1877, and dated the 21st March 1877.
PROVISIONAL SPECIFICATION left by the said Andrew Ronald Nairne and
James Waddell at the Office of the Commissioners of Patents on the 21st March
1877.
ANDREW RONALD NAIRNE and JAMES WADDELL, in the Employment of Messieurs
Moses McCulloch and Company, Ironfounders, of Glasgow, in the County of Lanark,
North Britain. "IMPROVEMENTS IN TRANSLUCENT GRATINGS FOR COVERING
HORIZONTAL, VERTICAL, OR OTHER OPENINGS OF CELLARS OR OTHER CHAMBERS OR
SPACES."
This Invention relates to translucent gratings for covering horizontal, vertical, or
other openings of cellars, or other chambers or spaces, that is, to gratings which
require to be of considerable strength, and at the same time to allow as much light
as possible to pass through them, and the Invention aims at securing such objects
in an improved manner, and also provides for the light proceeding in particular
directions after passing through the gratings.
The improved translucent gratings consist as heretofore of strong cast-iron grated
frames formed with comparatively small holes of triangular, rectangular, or poly-
gonal forms, or of circular or other curved forms, such holes being fitted with thick
pieces or blocks of glass.
The improvements consist essentially in giving to the glass blocks a certain form,
according to the special object in view in each case. Each glass block is made flat
and smooth, or more or less roughened on its upper or outer surface, whilst on its
under or inner surface three or other convenient number of projecting angular flat-
sided ridges are formed which resemble ordinary triangular prisms, and transmit
and direct the light in an abundant and effective manner.
When it is wished to have the benefit of the light directly below or opposite the
grating, all the prismatic ridges are by preference made of the saine size, but when

page_text: it is wished to direct the light to one side, the prismatic ridges are made of graduated
sizes, and the blocks are fixed with the smaller ridges nearer the side to which it is
wished to direct the light.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Andrew Ronald Nairne and Jaines Waddell, in the Great Seal
Patent Office on the 19th September 1877.
ANDREW RONALD NAIRNE and JAMES WADDELL, in the Employment of Messieurs
Moses McCulloch and Company, Ironfounders, of Glasgow, in the County of Lanark,
North Britain. "IMPROVEMENTS IN TRANSLUCENT GRATINGS FOR COVERING
HORIZONTAL, VERTICAL, OR OTHER OPENINGS OF CELLARS OR OTHER CHAMBERS OR
SPACES."
Our said Invention relates to translucent gratings for covering horizontal, vertical,
or other openings of cellars or other chambers or spaces, that is, to gratings which
require to be of considerable strength, and at the same time to allow as much light
as possible to pass through them, and our Invention aims at securing such objects
in an improved manner, and also provides for the light proceeding in particular
directions after passing through the gratings.
Our improved translucent gratings consist as heretofore of strong cast-iron grated
frames formed with comparatively small holes of triangular, rectangular, or poly-
gonal forms, or of circular or other curved forms, such holes being fitted with thick
pieces or blocks of glass.
.
Our improvements consist essentially in giving to the glass blocks a certain formn,
according to the special object in view in each case. Each glass block is made flat
and smooth, or more or less roughened on its upper or outer surface, whilst on its
under or inner surface three or other convenient number of projecting angular flat-
sided ridges are formed, which resemble ordinary triangular prisms, and transınit
and direct the light in an abundant and effective manner.
When it is wished to have the benefit of the light directly below or opposite the
grating, all the prismatic ridges are made of graduated sizes, and the blocks are
fitted with the smaller ridges nearer the side to which it is wished to direct the
light.
And in order that our said Invention and the manner of performing the same
may be properly understood, we hereunto append a Sheet of explanatory Drawings,
to be herein-after referred to, and representing an example of our improved grating
and glass blocks for the same. In these Drawings the same reference numerals are
'used to mark the same or like parts wherever they are repeated.
Figure 1 is a vertical section showing one of our improved translucent gratings as
applied to a cellar light in an ordinary street footpath.
Figure 2 and 3 are an edge view and an inverted plan (drawn full size in the
Drawings accompanying this Specification), and show a modification of glass block
suitable for the grating shown in Figure 1. In this example the grating comprises
a plain rectangular cast-iron frame 4, formed with rectangular openings, in which
openings there are cemented blocks 5 of glass, formed as shown in Figures 2 and 3.
Each glass block is formed with three angular flat-sided projecting ridges 6, 7, 8,
which are of graduated sizes, and which are arranged in the grating with the
Jarger ridges of each block further than the smaller ones from the cellar 9, which it
is wished to illuminate. The light entering the glass blocks vertically is partly
subjected to internal reflection at the angular surfaces of the projecting ridges, and
the light (or some of it) so reflected from the outer sides of the outer ridges passes
under the inner and smaller ridges towards the cellar 9, which is in consequence
better illuminated than if all the light passed down in a vertical direction from the
under side of the grating.

page_text: The dotted lines indicated the directions of the light rays which are thus directed
towards the cellar 9.
Having thus particularly described our said Invention and the manner of per-
forming the sanie, we have to state that we do not restrict ourselves to the preciso
details herein described and delineated, but that what we believe to be novel and
original, and claim as the Invention secured to us by the herein-before in part
recited Letters Patent is,-
1. The fitting of translucent gratings for covering horizontal, vertical, or other
openings of cellars, or other chambers or spaces, with glass blocks formed with
angular flat-sided ridges on their under sides as herein-before described.
2. The making of the glass blocks of translucent gratings with angular flat-sided
ridges of graduated sizes as used for the purposes herein-before described.
In witness whereof, we, the said Andrew Ronald Nairne and James Waddell,
have hereunto set our hands and seals, this Eighteenth day of September,
in the year of our Lord One thousand eight hundred and seventy-seven.
Witness,
EDMUND HUNT,
Patent Agent,
Glasgow.
ANDREW RONALD NAIRNE. (L.S.)
JAMES WADDELL.
(L.S.)