Improvements in Lamps for Overhead Lighting.
Year: 1893

page_text: Date of Application, 30th Dec., 1893
Complete Specification Left, 1st Oct., 1894-Accepted, 3rd Nov., 1894
PROVISIONAL SPECIFICATION.
Improvements in Lamps for Overhead Lighting.
I, THOMAS COOPER JOHN THOMAS, of 5 Carlton Road, Finsbury Park,
London N., Engineer, do hereby declare the nature of this invention to be as
follows:-
A lamp according to this invention is constructed with a burner or burners
enclosed within a bowl and having above it a reflector that is pierced by an
annular row or rows of holes for the escape of heated air and products of
combustion from the bowl into the chimney, air to support combustion being
admitted to the bowl around the periphery of the reflector, near the rim of the
bowl. Reflectors with air holes as described for the purpose mentioned may be
made in various forms.
In one construction the reflector resembles a truncated hollow cone or conical
annulus with a central flattened dome or cap-like part that stands up within the
lower part of the lamp chimney the before-mentioned perforations being made
through the annular wall of the said central part; but the reflector may be entirely
conical, the holes being formed in an annular row or rows a suitable distance from
the apex; or the central part may be dished.
In either case the annular part surrounding the perforated central part may be
inclined or curved in an upward direction or may be horizontal.
Dated this 30th day of December 1893.
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C., Chartered Patent Agent.
COMPLETE SPECIFICATION.
Improvements in Lamps for Overhead Lighting.
1, THOMAS COOPER JOHN THOMAS, of 5 Carlton Road, Finsbury Park,
London, N., 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 :-
A lamp according to this invention is constructed with a burner or burners
enclosed within a bowl and having above it a reflector that is pierced by an
annular row or rows of holes for the escape of heated air and products of
combustion from the bowl into the chimney, air to support combustion being
admitted to the bowl around the periphery of the reflector, near the rim of the
bowl. Reflectors with air holes as described for the purpose mentioned may be
made in various forms.
In the accompanying illustrative drawings,
Fig. 1 is a vertical section of a railway carriage roof lamp with combined
reflector and chimney constructed according to this invention.
Figs. 2 to 5 inclusive are vertical sections showing various modified constructions
of combined reflectors and chimneys according to this invention.
In the construction shown in Fig. 1, the reflector 1 resembles a truncated hollow
cone or conical annulus with a central flattened dome or cap-like part 2 that stands

page_text: up within the lower part of the lamp chimney 3 to which the reflector is secured,
and the holes 4 through which the heated air and products of combustion escape
from the lamp bowl 5 into the chimney 3 are made through the annular wall of the
central part 2.
Air to support combustion reaches the burner 6, as indicated by
arrows, through holes 7 in the head 8 of the lamp and through holes 9 made in a
vertical wall 10 arranged around the periphery of the reflector 1 near the rim of
the bowl 5.
The reflector is provided at its periphery with an annular horizontal flange 11
by which it is supported upon the Hanged ring 12 ordinarily used for securing the
lamp bowl 5 within the lamp casing 13, the said flange being recessed at one side,
as at 11, to accommodate the pivoted gas supply pipe 14.
In the construction shown in Fig. 2, the reflector 1 is entirely conical and the
holes that give access to the chimney 3 are formed in an annular row at a
suitable distance from the apex 1". In other respects the combined reflector and
chimney is similar in construction to that shown in Fig. 1.
The arrangement shown in Fig. 3 is similar to that shown in Fig. 1 with the
exception that the truncated hollow cone forming the reflector is inverted,
i.e. points downwards instead of upwards as in Fig. 1.
In Fig. 4, the central part 2 of the reflector 1 is made in the form of a dish; it
may be arranged to be either concave as regards the burner, as shown in full lines,
convex thereto, as indicated in broken lines. The anunlar part of the
reflector surrounding the perforated central part 2 is in this case arranged
horizontally.
or
Fig. 5 shows a construction in which the reflector 1 with cap-like part 2 and
perforations 4 is similar to that shown in Fig. 1 but the holes 9 are not made in a
flanged part of the reflector 1 itself, but in a separate piece 10, which is secured
to the chimney 3 by riveting, or in any other suitable manner and may be removably
attached to the reflector 1 by bolts 15. In this case the supporting flange 11 is on
the piece 10%.
In order to facilitate the lighting of the lamp, the cap-like or equivalent part 2
may be provided with a narrow slit 16 as shown in Fig. 6. Or the said cap-like
or equivalent part 2 may be made separate from the remainder of the reflector and
be pivoted on a cross pin 2 as shown in vertical section in Fig. 7 and in plan in
Fig. 8, so as to form an unbalanced flap that will normally rest in the position
shown in full lines in Fig. 7 but is free to he moved into the position shown in
dotted lines by a torch or other lighting device passed down through the chimney
when lighting the lamp.
Although I have shown my invention as applied to a railway carriage roof lamp
it will of course be understood that my improvements are equally applicable to
street and other overhead lamps.
By my invention I can produce in a simple and inexpensive manner efficient
reflectors wherein there is no comparatively large dark space, such as is commonly
observable at the centre of overhead lamps, and corresponding to the lower open
end of the chimney, whilst provision is made without materially detracting from
the efficiency of the reflector, for the direct passage of the hot gases and products
of combustion from the lamp bowl or lantern into the chimney.
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 :-
1. A lamp for overhead lighting, constructed with a burner or burners enclosed
within a bowl and having above it a reflector provided in its central part with an
annular row or rows of holes, in lieu of a large central hole, for the escape of
heated air and products of combustion from the bowl into the chimney substantially
as herein described.
2. In a lamp for overhead lighting, a reflector having its central part unperforated
and of dome, cone or dish-like form, and around such part and in proximity thereto,

page_text: one or more rows of holes for the escape of heated air and products of combustion
substantially as herein described.
3. For lamps designed for overhead lighting, combined reflectors and chimneys
constructed substantially as herein before described with reference respectively to
and shown in Fig. 1; in Fig. 2; in Fig. 3; in Fig. 4; and in Fig. 5 or modified
as in Fig. 6, or as in Figs. 7 and 8 of the drawings annexed for the purpose
specified.
Dated this 29th day of September 1894.
THOMAS COOPER JOHN THOMAS.
W. Lloyd Wise,
46, Lincoln's Inn Fields, London, W.C.