IMPROVEMENTS IN LAMPS, CHIEFLY APPLICABLE TO HEAD AND TAIL LAMPS FOR RAILWAY TRAINS
Year: 1880

page_text: PROVISIONAL SPECIFICATION left by Jaines John Frederick Stevens at the
Office of the Commissioners of Patents on the 1st May 1880.
JAMES JOHN FREDERICK STEVENS, of Darlington Works, Southwark, in the
County of Surrey, Railway Signal Manufacturer. "IMPROVEMENTS IN LAMPS,
CHIEFLY APPLICABLE TO HEAD AND TAIL LAMPS FOR RAILWAY TRAINS."
This Invention consists of improvements in lamps, and relates more particularly
to head and tail mineral oil or ordinary oil lamps for railway trains. In these
lamps the jolting of the train sometimes causes the wick to rise or fall, the result
being either that the light flares or that it becomes dim or goes out. The ventilation
in head and tail lamps as ordinarily constructed is also defective; sometimes,
according to the temperature of the atmosphere and other circumstances, the lamp
is draughty, and at other times the ventilation is insufficient. Another defect in
these lamps is that the light is liable to be blown out by the wind when the door.
of the lamp case is opened for any purpose, or when the lamp proper is being put
into place; and for this reason it is generally necessary to lift the heavy case off
the engine or van and carry it to the lamp room or some other place free fron
draught. A further defect is that the oil in the lamp reservoir is liable to become
overheated.
Now my improvements consist in providing the lamp with means of fixing the
wick so that the jolting of the train cannot cause it to rise or fall; also in improved
means of ventilating and of regulating the ventilation of the lamp; also in
constructing the lamp with a movable inner case in which the lamp proper is
fitted, the said inner case itself fitting into the outer case; and also in an improved
construction of the oil reservoir to prevent the oil getting overheated.
Various means may be adopted for fixing the wick according to my Invention,
but the mode I prefer is to fit a toothed wheel on the spindle of the pinion, by which
the wick is moved up or down in the ordinary manner, and to employ a weighted
lever with catches to take into the said wheel, so that the wheel, and therefore the
pinion, cannot move in either direction unless the lever is raised to free the catches.
A spring is fitted to act upon the lever and prevent its being raised by the jolting
of the train.
My improved means of ventilating and of regulating the ventilation of the lamp
consists in forming an opening in the top of the outer caso, from each of the sides

page_text: of which opening is carried up a vertical plate; above the opening and the vertical
plates, but not touching the plates, is a hood, and above this hood is a second hood.
The outer hood is enclosed at the ends. The air and products of combustion which
escape through the opening in the top of the case pass over the top and beyond the
ends of the vertical plates into the inner hood, and thence through openings in the
sides and ends of the inner hood into the outer hood. The outer hood has holes at
the sides, and other holes at the top, and some of these holes, preferably the top
ones, are capable of being partly or entirely closed by means of a slide or shutter so
as to regulate the draught. The top holes and slides may be covered by a third
hood opened at the ends. Apertures for admitting the necessary air to the lamp may
be formed in the bottom or lower part of the outer case.
The inner case herein before described is by preference rectangular and made of
tin, glass being fitted at the side which comes between the lamp and the lens. It
has projecting lips or flanges to enable it to slide into corresponding guides in the
outer case, and it is provided with similar guides to receive projecting lips or flanges
on the lamp proper. It has openings at the bottom to admit air, and at the top
there is an opening fitted with a cap formed so that the escaping air and products
of combustion are diverted downwards.
The improved oil reservoir for the lamp is made with a central opening extending
from top to bottom, in which is a chamber of smaller diameter than the said
opening, so that there is an annular space between them through which a current
of cold air passes. This inner chamber receives the lower part of the wick, and
communicates with the reservoir by one or more tubes at the lower part. Above
the reservoir, the top of which is by preference inclined, is a cover separated from
the reservoir by a space of about half an inch; through this space the current of
air which passes up the central opening of the reservoir escapes after having exerted
a cooling effect upon the reservoir.