Year: 1887

page_text: [Communicated from abroad by CHARLES STANFORD UPTON, of New York City,
County and State of New York, in the United States of America, Merchant.]
I JAMES YATE JOHNSON of 47 Lincoln's Inn Fields in the County of Middlesex
Gentleman do hereby declare the nature of this Invention which has been
communicated to me from abroad by Charles S. Upton of the United States of
America and in what manner the same is to be performed to be particularly described
and ascertained in and by the following statement :-
This Invention relates to improvements in Argand or central draught lamps and
more particularly to the construction of the cap cone or thimble which seats within
the central tube and which directs the inner draught upon the flame to improve the
combustion of the oil, vapour or gas. This cap is preferably made of finely perforated
sheet metal and is removably inserted in the upper end of the inner draught tube ;
and it is made somewhat smaller in exterior diameter than the interior diameter of
the said tube so as not to be in contact therewith and thereby not to impart its heat to
the tube, and so as to allow the current of air to pass through it throughout its entire
length, as far as practicable. This Invention consists in the means for holding the
cap steadily and adjustably in the tube and thus allowing the difference in diameters
of the two parts as specified.
According to this Invention outward projections or bosses are formed on the
cap preferably by swaging the metal of the same outward substantially as hereinafter
set forth.
The invention also consists in forming the cap cone or thimble of a single piece of
metal and providing it with an imperforate top and an outwardly projecting retaining
flange or rim to seat upon a stop or bead formed upon the central draught tube, and
in other features of construction as hereinafter described.

page_text: Figure 1 of the accompanying drawings represents a central vertical section of
the cap placed in the inner draught tube separately from the other parts of the lamp.
Figure 2 represents the cap separately.
Figures 3 and 4 represent modifications of the same.
Like reference letters designate corresponding parts in all these figures.
A represents the inner draught tube and B the perforated cap of an Argand or
central draught lamp. In order to hold the cap of smaller diameter in the tube of larger
diameter so as to be retained centrally therein, several small bosses or outward
projections a a are swaged or stamped in the cap from the inside outward, or are
otherwise formed the outermost part of the same being preferably rounded and of
just sufficient projection to touch the inner surface of the tube as shewn in Figure 1.
The apex of each boss or projection is but small or narrow and when of the rounded
form shown touches the tube only tangentially and consequently with a very narrow
contact therewith sufficient to hold the cap in place. They fit in the tube A with
just enough friction or pressure to retain the cap firmly and securely in place in any
position in which it may be adjusted in the said tube.
There may be three four or more of the bosses or projections on the cap at intervals
around its periphery and preferably at equal or nearly equal heights thereon. They
may be round as shown in Figure 1, or somewhat elongated vertically as shown in
figure or as shown in Figure 2 or of any other equivalent or suitable form or
arrangement. As shewn in Figures 1, 2 and 3 the said cap may be provided with a
slightly outturned edge or rim b at the lower open end of the cap reaching nearly to
the interior surface of the tube though preferably not quite filling the same, as shown
in Figure 1 except if preferred at two or three points. This rim also serves as a stop
to rest on an inner bead or projection, C, C, on the inner surface of the tube A, to
limit the extent to which the cap can be inserted into the tube A. The cap may be
adjusted in position above this lowest limit to as high a position as the bosses a a will
permit without coming out of the tube, the bosses being situated as high on the cap
as the necessary extent of adjustment will allow. With the elongated bosses as shewn
in Figure 3 no rim or outward turning b at the lower end of the cap is necessary for
the purpose of holding the cap in the tube.
In this kind of holding projections or stays no additional parts are required in their
formation and therefore the construction is cheap nor are any of the parts liable to be
broken off. Further these projections are quickly made and applied and being
perforated do not materially impede the passage of air through the cap at any point.
Another mode of securing this perforated cap to the central draught tube is to
provide the former with an annular collar d Fig. 4 which fits over the end of the
central draught tube A and is locked in position by means of the notch e and pin fin
the collar and tube respectively.
Having now described and particularly ascertained the nature of this Invention
and in what manner the same is to be performed I declare that what I claim is :—
First In an argand or central draught lamp-burner, and in combination with
the central tube, a cap cone or thimble having its sides perforated and having
outwardly swaged portions in or projections on its sides to bear against the interior of
the tube, and with or without a projecting flange or rim in a different horizontal
plane from the said outwardly swaged portions or projections whereby the said cap
cone or thimble is adapted to seat against the sides of the tube and is maintained in
upright position substantially as hereinbefore described.
Second-The combination in an argand or central draught lamp of a central tube
provided with a bead or stop with a removable cap cone or thimble having its sides
perforated, and having an outwardly turned flange or rim adapted to rest on the said
bead or stop substantially as herein before described.
:
Third The combination in an argand or central draught lamp of a central tube
provided with a bead or stop with a cap cone or thimble having its sides perforated
and having outwardly-swaged projections in the said sides and with or without an

page_text: out turned flange or projection at its lower end, having a seating on the said bead or
stop substantially as set forth.
Fourth-The combination with the central tube of an argand or central draught
lamp of a cap cone or thimble formed in one piece having an unperforated top and
perforated sides with outwardly swaged or equivalent projections adapted to seat
against the sides of the tube and with or without a projection or outturned portion at
its lower end also seating against the said tube substantially as set forth.
Fifth-In an argand or central draught lamp a removable cap cone or thimble
made of a single piece of metal having perforated sides, in combination with the
central tube of an argand lamp all arranged substantially as set forth and illustrated
in the Drawings.