Improvements in Lamps and the Reflectors therefor.
Year: 1889

page_text: Date of Application, 12th Dec., 1889
Complete Specification Left, 31st July. 1890-Accepted, 6th Dec., 1890
PROVISIONAL SPECIFICATION.
Improvements in Lamps and the Reflectors therefor.
I, ALFRED JOHN LOFTUS (Phrá Nidesa Jalahdi K.C.C.S.), of Wat Chang, Bangkok,
Siam, Captain and Hydrographer in His Siamese Majesty's Navy, do hereby declare
the nature of my said invention for "IMPROVEMENTS IN LAMPS AND THE REFLECTORS
THEREFOR to be as follows:-
"
My invention has reference to the mechanical arrangements and fittings of the
lamp including the reflectors, whereby I am able to concentrate and utilize the light
in a specially advantageous manner, and such reflectors made according to my said
invention are applicable to other forms of lamps such as gas-brackets, chandeliers,
and the like.
My lamps, made according to this invention, are particularly adapted for the use
of draughtsmen and students, and as search lights on business and domestic
premises, in camps, diggings, on shipboard, for travellers, and for many other
purposes, a concentrated beam of nearly parallel and diverging rays being emitted
and affording a brilliant illumination at a long distance.
According to my invention I fit each lamp, gas-bracket, chandelier, or the like
with a reflector or reflectors, and I prefer to supply three reflectors with each lamp,
such reflectors being made interchangeable as herein-after described, so that one may
be taken off and replaced by another with great facility according to the purpose to
which the lamp is to be applied.
I prefer to construct my lamps with a dish or tray forming the base, and the
central portion of which forms part of the oil reservoir. From the top of the oil
reservoir, in the centre thereof, rises a vertical stem which serves to carry the
reflectors, and to the back of which I may attach a loop, scroll, or other device,
which serves as a handle and which may also be attached to the oil reservoir or
to the dish or tray before mentioned. The upper part of the oil reservoir I prefer to
make with an opening through which it may be filled, and a screw plug for the same.
From the front of the oil reservoir I lead a curved pipe terminating vertically in a
burner fitted with means for carrying a glass chimney, and for adjusting the wick,
and the like.
To the back of each reflector I attach a stem carrying at its end a ferrule, or
thimble, made to fit the vertical stem, or the end thereof, in such a way that on
slipping the said ferrule or thimble over the top of the stem the reflector is held in.
its proper position, and I may provide means for adjusting the position of the reflector
both vertically and horizontally.
The reflectors are formed with the central part having a spherical curve and the
surrounding part, towards the edge, a parabolic curve, and I may construct them of
the following dimensions which I have found convenient for hand lamps and the like,
but I do not limit my invention to these sizes or dimensions which are the details
of the three reflectors intended to form one set and to be supplied with each of the
hand lamps more particularly described above, but larger or other sizes are required
for larger or other lamns

page_text: fixed on the back of each, whereby the reflectors slide for the purpose of focussing up
and down a vertical stem so fixed to the bracket, chandelier, or the like, as to fix and
clamp in any required position, a horizontal adjustment is also sometimes provided,
and several or a series of such lamps, each with its reflector, may be united or
constructed together, so as to light all round, or to any angle of divergence.
Dated this h
בז •
1000
COMPLETE SPECIFICATION.
Improvements in Lamps and the Reflectors therefor.
I, ALFRED JOHN LOFTUS, (Phrá Nidesa Jalahdi, K.C.C.S.) of Wat Chang, Bangkok,
Siam, Captain and Hydrographer in His Siamese Majesty's Navy, do hereby declare
the nature of my said invention for "IMPROVEMENTS IN LAMPS AND THE REFLECTORS
THEREFOR and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement :-
39
My invention has reference to the mechanical arrangements and fittings of the
lamp including the reflectors, whereby I am able to concentrate and utilize the lights
in a specially advantageous manner, and such reflectors made according to my said
invention are applicable to other forms of lamps such as gas-brackets, chandeliers,
and the like.
My lamps, made according to this invention, are particularly adapted for the use of
draughtsmen and students, and as search-lights, on business and domestic premises,
in camps, diggings, engine rooms, manufactories, workshops, vaults, passages, on
shipboard, for travellers, and for many other purposes; a concentrated beam composed
partly of parallel and partly of diverging rays being emitted and affording a brilliant
illumination at a long distance.
According to my invention I fit each lamp, or burner with a reflector or reflectors,
and I prefer to supply three reflectors with each lamp, such reflectors being made
interchangeable as hereinafter described so that one may be taken off and replaced
by another with great facility according to the purpose to which the lamp is to be
applied.
I prefer to construct my lamps with a dish or tray forming the base, and the central
portion of which forms part of the oil reservoir. From the top of the oil reservoir,
in the centre thereof, rises a vertical stem which serves to carry the reflector, and to
the back of which I may attach a loop, scroll or other device, which serves as a
handle and which may also be attached to the oil reservoir or to the dish or tray
before mentioned. The upper part of the oil reservoir I prefer to make with an
opening through which it may be filled, and a screw plug for the same. From the
front of the oil reservoir I lead a passage terminating vertically in a burner fitted
with means for carrying a glass chimney, and for adjusting the wick and the like.
On the under part of the tray circular rings of rubber or the like are fixed to keep
the lamp firm and from slipping.
To the back of each reflector 1 attach a stem carrying at its end a ferrule or a
thimble made to fit the vertical stem, or the end thereof, in such way that on slipping
the said ferrule or thimble over the top of the stem, the reflector is held in its proper
position, and I may provide means for adjusting the position of the reflector both
vertically and horizontally.
In the accompanying sheet of drawings Fig. 1 represents a side elevation of one
of my hand lamps with a burner of the ordinary type and with a reflector herein-
after described more particularly. Fig. 2 is a section of the same lamp. Fig. 3 is
a side elevation partly in section, of an otherwise similar lamp with a burner which
I have specially devised for these and signal lamps. Fig. 4 shows plans of the
three reflectors which I prefer to fit to each lamp and which I describe by the
letters A, B, and C respectively, that marked being also shown on the lamps.
D, is the oil reservoir rising from a dish or tray E, which also forms the bottom of

page_text: the reservoir, F is a stem which serves to carry the reflector and to which one end
of the handle G is attached. g is a case intended for the reception of a box of
matches. H is a screw plug serving to close the opening through which the lamp is
filled.
At the back of each reflector is a short stem K carrying at its extremity a ferrule
or a thimble L which fits over or on to the stem F and thereby supports the reflector
in its place and also admits of the reflectors being changed with great facility. In
Figs 1 and 2, 1 is the burner of any well known type, preferably "Argand,"
and the kind known in the trade as "
"
Kosmos answer well, the details of such
a burner are shown in section in Fig. 2 but form no part of this invention.
In Fig. 3 an improved form of burner is shown which I have designed after many
experiments. It differs from that just described in having that part of it known as
the cone, or wick tube I¹ one inch, to one inch and a quarter, longer than is usual,
and this enables me to place the reflector higher than that shown in Figs. 1 and 2,
for which purpose I make the stem F longer than is shown in those figures, and thus
keep the lower edge of the reflector at a level at which it may be less cut away and
is less in the shadow of part of the burner, and is thus better illuminated and reflects
more light. Moreover by employing a longer cone, I obtain a more perfect combus-
tion and whiter light and less deposit is formed at the top of the wick and on the
surrounding parts.
The reflectors are formed with the central part having a spherical curve and the
surrounding part, towards the edge a parabolic curve. In a section of such a reflector
the central portion, or that portion having a circular curve, forms an arc of from 50
to 90 degrees, that is to say, the spherical portion of the reflector may extend to an
angle of from 25 to 45 degrees on each side of the optical axis of the reflector, such
angle being measured from the point forming the centre of the curve. Beyond the
circular portion the curve passes insensibly into a parabolic curve such that, as seen
in section, the two curves have at the point of junction a common tangent, and the
parabolic curve is such that its focal point is identical with the centre of the circular
portion. I may construct such reflectors of the following dimensions which I have
found convenient for hand lamps, and the like, although sometimes I fit my hand
lamps with larger, say 8 inch reflectors, but I do not limit my invention to these
sizes or dimensions which are the details of three reflectors intended to form one set
and to be supplied with each of the hand lamps before described, but larger or other
sizes. are required for larger or other lamps.

page_text: 2. Constructing lamps with Argand burners, having a cone longer by about one inch
to one inch and a quarter than they have hitherto, been used, as shown in Fig. 3 of
the drawings.
3. Constructing reflectors for lamps with the central portion having a spherical,
and, the outer portion a parabolic curve arranged and combined substantially as
hereinbefore described and set forth.
ALFRED OHN LOFTUS...