Improvements in Street Lamps and Lamps of the like kind.
Year: 1893

page_text: Date of Application, 16th Dec., 1893
Complete Specification Left, 16th Oct., 1894-Accepted, 24th Nov., 1894
PROVISIONAL SPECIFICATION.
Improvements in Street Lamps and Lamps of the like kind.
We, Captain Sir ALFRED JOHN LOFTUS, Phrá Nidesa Jalahide, K.C.C.S. of
Ban Phrá Nehtate, Grosvenor Road, Handsworth, Birmingham, in the County of
Warwick, Retired Hydrographer from the Siamese Government Service; and
EDWARD ROWLANDS, of Colmore Row, Birmingham, aforesaid, Solicitor, do
hereby declare the nature of this invention to be as follows:-
Our invention is intended more particularly for application to street lamps but it
is also applicable to other lamps of a like character that is to say to lanterns of
rectangular or polygonal form.
According to our invention we place in each pane, or some of them, a glass
meniscus the inner or concave surface of which is of such curve as to reflect as
much as possible of the light which does not pass through it, back in parallel or
nearly parallel rays and send such reflected rays through and out the opposite side
of the lantern in a useful beam of light, and so that an observer standing at a
distance from the lamp sees not only the flame but behind it a reflection in the
concave surface of the glass which appears filled by the magnified image of the
flame.
To insure the most perfect curve for the concave surface of the meniscus we
prefer to make it of the curve, or one of the curves, described in the Specifications
of Patents granted to the first named applicant and dated December 12th 1889
No. 20023 and August 19th 1891 No. 14034.
These transparent reflectors which reflect only so much of the light as does not
pass through them thus utilizing a large portion of the light which with ordinary
lanterns is wasted or nearly so, may be inserted into the panes by means of the
ordinary window lead commonly used for such purposes, or the plain sheet of glass
may itself be moulded or stamped while hot into the shape required.
The outer surface of the meniscus may be either parallel to the inner surface or
otherwise, according as it is desired to bend the rays passing through, or not to
bend them.
It is generally convenient to make each of the panes in two or four pieces in
order to facilitate the cutting out of the centre portion and the insertion of
the meniscus, or to fit the lamps with meniscuses only i.e. without fixing them in
panes.
The panes forming the sides may be either vertical or inclined inwards or
outwards according to the direction in which it is desired to direct the principal
illumination and the optical axis of the meniscus should correspond with the said
direction.
In existing lamps we place the discs in exact focal position inside the lamps.
They are kept so by means of wire supports from the frame and are removeable
for cleaning etc.
In some cases we surmount the square (or other) lamp with a glass globe or other
dome or figure which being illuminated by the flame in the lantern below increases
the illumination. The flat surfaces of the panes or the globe or part of one or
some of these may in some cases be opalled, corrugated or the like with advantage.
We use in some cases a burner specially constructed for these lamps whereby two
flat flames are combined at right angles to and intersecting each other in the centre
so as to expose a flat surface towards each pane.

page_text: Lamps constructed according to our invention give a much better illumination
from a given burner than the lamps now in common use.
Dated the 16th day of December 1893.
NEWNHAM BROWNE,
Agent for the Applicants.
COMPLETE SPECIFICATION.
Improvements in Street Lamps and Lamps of the like kind.
We, Captain Sir ALFRED JOHN LOFTUS, Phrá Nidesa Jalahide, K.C.C.S., of
Ban Phrá Nehtate, Grosvenor Road, Handsworth, Birmingham, in the County of
Warwick, Retired Hydrographer from the Siamese Government Service, and
EDWARD ROWLANDS, of Colmore Row, Birmingham, aforesaid, Solicitor, 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 :-
Our invention is intended more particularly for application to street lamps but it
is also applicable to other lamps and consists principally in arranging in each pane,
or in one or more of them, or, in the case of an existing lamp, then within said
lamp a glass meniscus the inner or concave surface of which is of such a curve as
to reflect as much as possible of the light which does not pass through it, back in
diverging or nearly parallel rays, and send such reflected rays through and out of the
opposite side of the lantern in a useful beam of light, so that an observer standing
at a distance from the lamp and looking into the meniscus at the farther side of
the flame not only sees the flame but behind it also a reflection in the concave
surface of the glass, which latter appears filled by the magnified image of the
flame.
The word "meniscus " is used throughout this Specification and is to be under-
stood as meaning a lens in which the opposite surfaces are both curved in the same
direction whether they are parallel or otherwise, the surface contiguous to the flame
having the desired reflective action.
The lamps may be constructed in various ways whereof a few examples are
given in the accompanying drawings by reference to which latter the invention will
be best. understood.
In those drawings,
Figure 1 is an elevation partly broken away, of one form of the lamp constructed
according to our invention. Figure 2 being a horizontal section taken on line 2-2
of Figure 1.
Figures 3 and 4 are respectively an elevation and a transverse section of a portion
of one of the straight glazing frames used in the construction of the lamp shewn in
Figures 1 and 2 and Figures 5 and 6 are similar views of a portion of one of the
curved or circular glazing frames.
Figure 7 is an elevation of one of the complete frames or sides, with meniscus
fitted therein, of the lamp shown in Fig. 1.
Figure 8 is an elevation of another form of the lamp. Fig. 9 being a horizontal
section of the same taken on line 9. 9 of Fig. 8.
Figure 10 is an elevation of a further form of the lamp.
Figure 11 is an elevation shewing how our invention may be applied to existing
lamps.
Figure 12 is an enlarged perspective view of portion of Figure 11 and
Figure 13 is a diagram illustrating the application to this particular case of the
manner of producing the particular curve described in Specification 14034" of the
meniscus constructed according to our invention.
Throughout the drawings like letters of reference indicate like parts.
The lamp shown in Figures 1 and 2 and of which various detached portions are
also shewn in Figures 3, 4, 5, 6 and 7 is constructed with a metal frame A

page_text: (conveniently of zinc) of generally square form in horizontal section as shewn in
Figure 2, the body or lower portion B having four sides or walls (whereof one is
shewn detached in Figure 7) each of which may be vertical or as shewn in the
example illustrated, inclined, inwards or each may be inclined outwards, or some
may be vertical and others inclined inwards or outwards according to the direction
or directions in which it may be desired to direct the principal illumination.
The lower portion or body B is surmounted by a glass roof B' which itself is
surmounted by a crown portion C terminating at its upper part in an ornament D
which we prefer to make in the form of an acorn. The crown portion C as
represented in dotted lines in Figure 1 is provided with the necessary outlets C¹ C³
for admitting of the escape of the heated products of combustion and with
guards CC for preventing the wind blowing down into the lamp.
At its lower part the body B is closed in by a flat floor E in which is provided
the usual inwardly opening door E' for the insertion of the lamp lighter's torch.
Each side of the body B together with the meniscus F fitted therein as shewn
in Figure 7 is formed complete in itself and may as a whole be fitted in the lamp
framing A and we prefer to do this so that should any part become broken, the
damaged portions may be expeditiously removed and replaced. To obtain this
result we form the flat part of each side in two pieces such as G, G¹ one to fit
above and the other below the meniscus F, these being held together by a grooved
frame H of conveniently the section shown in Figure 4, the edge of the glass
fitting into the groove H¹ of said frame as will be well understood. The top rail of
the frame H is cut across the greater part of its substance as at H2 Figure 7 for a
purpose hereinafter described. The meniscus F is fitted into the frame G. G¹ by
means of a metallic circular frame I a portion of which is shewn in Figure 5 and
the preferred shape of which in cross section is shewn in Figure 6 from which
latter figure it will be seen that said frame I is provided with an outer groove I
for receiving the surrounding edges of the glass pieces G. G¹ and an inner groove I*
for receiving the outer edge of meniscus F shewn in Figure 1. The circular
frame I may be formed from a strip of the metal shewn in Figure 5 or otherwise
but however produced it is left with a break or disconnection as at I³ so as to
enable it, after removal from the frame H as hereinafter described to be sprung
open to admit of a damaged meniscus F being removed and a fresh one substituted
for it.
The before described parts comprised in each side of the lamp body are put
together in the following manner.
The two side rails and the top rail of the frame H are placed in position
and soldered together at the corners h³. The glass piece G is next pushed into
the then open-ended frame H until its top edge fits into the groove H (Figure 4)
of the top rail. The meniscus F is then pushed into the circular frame I which
latter is sprung open sufficiently to receive it, and the frame I together with said
meniscus is pushed into the frame H the sides of the circular frame I preferably
fitting over the frame H as shewn in Figure 7, though if desired the frame I at
these parts may fit within the groove of frame H; whatever the construction
however the frame I is in no way permanently connected to the frame H at these
or any other parts. The glass piece G¹ is then fitted in the outer groove I'
(Fig. 6) of the frame I at its lower part after which the bottom rail is placed
in position (its groove H¹ Fig. 4 receiving the lower edge of G¹) and is soldered
to the rails at the corners. The whole may then be fitted into the lamp frame A
in any convenient manner.
.
In case of breakage, either of the parts G F or G¹ may be readily removed and
have unbroken parts substituted therefor by unsoldering the joints . When these
joints have been unsoldered the rails h are opened out a little and the whole of the
internal parts F, G, G, and I, come away together. Any unbroken part can be
replaced by an unbroken one and the whole afterwards slipped back into the
frame H and the rail * of the latter again placed in position and soldered to the
side rails at the corners h after which the whole pane is replaced in the lamp

page_text: frame A. The slit H' enables the undivided part above it to act as a hinge. to
facilitate the opening or widening of the frame.
If desired the pieces G G¹ may each be formed of two symmetrical parts
meeting edge to edge at the centre of the lamp body. By forming the flat portions
of the lamp sides in two or four pieces as before described the cutting out of the
circular opening to receive the meniscus F is greatly facilitated.
One of the sides (for example that shown at the left hand side of Fig. 2) of the
before described lamp is hinged to form a door, whereby access may be had to its
interior.
The lamp shewn in Figs. 8 and 9 is provided with a glass globe or other dome J
over the lower part or body B which latter may be of substantially the form shewn
in Figures 1 and 2 though as shewn in Fig. 8 it is of somewhat more taper form,
the walls or sides towards the tops inclining inwards about 21 degrees from the
vertical. Such an arrangement as this results in the central rays passing out of the
lamp striking the ground in a circle of about 50 feet diameter.
In actual practice the globe or dome J becomes illuminated by the flame in the
lamp thereby increasing the illumination.
The globe J may be made of plain glass or its out surface may be corrugated cut.
or otherwise provided with prismatic forms for the purpose of still further
increasing the illumination of the lamps, or if desired the globe may be formed of
metal, painted or bronzed. For this same purpose the surfaces of the glass
pieces G G both of this lamp and others embodying our improvements may be
similarly corrugated or cut, or they may be formed of opal or translucent glass or
otherwise made semi-transparent.
The lower portion K of, the lamp shewn in Figure 8 may be of glass aud of the
partly rounded form illustrated to allow of the rays of light passing through it
without being deflected. The direction of the rays of light passing out of this
lamp are represented by the chain lines a.
Above the globe J the lamp may be surmounted by any suitable form of
chimney C for allowing the escape of the products of combustion and excluding
draught.
In the lamp shewn in Figure 10 another variation of form is embodied. Here
the rays as indicated by the chain lines are reflected at a less angle than in the
lamp last described. The optical plane of this lamp is at an angle of 140 degrees to
the vertical. This lamp is moreover shewn with only two meniscuses whereas,
like those previously described, it may have four if desired.
In applying our invention to an existing lamp K as shewn in Fig. 11 we place
the discs or meniscuses F in exact focal position within said lamp, for this purpose
conveniently supporting them in grooved crutches L secured to the outer ends of
bracket L projecting outwards from a sleeve L' encircling or fitting over the
burner tube L³. The arms of L' being preferably of diamond form in section so
as to interfere as little as possible with the illuminating effect.
To the burner tube L³ we conveniently fix a block or projection L adapted to
engage with a recess L in the sleeve I so as to secure the bracket arms L' and
discs Fin proper position in relation to the burner Lº. By raising the sleeve L' so,
as to disengage the recess L' from the projection L' the discs or meniscuses F may
be turned into any desired position to facilitate cleaning, or the discs may be
readily lifted out of the crutches L for cleaning or other purposes and subsequently.
replaced.
In the drawings illustrating the last described arrangement we have only,
shewn 2 discs F but we wish it understood that we may use 4 or other number if
desired.
In connection with lamps fitted with 4 discs F we prefer to employ a burner
giving as indicated in Figs. 1, 2, 8 and 9 two flames M, M' one crossing the other
at right angles so that a flat flame may be presented to each meniscus.
To obtain the best results from the employment of the meniscus F we prefer to
make the concave surface of each of them of the curve or one of the curves,
:..

page_text: described in the Specifications of Patents granted to the herein first named
applicant and dated December 12th 1889 No. 20023 and August 19th 1891
No. 14034.
"
Figure 13 of the accompanying drawings illustrates the application of the method
described in Specification 14034" to the particular case of a curve well suited for
these lenses. The letters of reference in Fig. 13 correspond to those used in the
said Specification.
The before described meniscuses constitute transparent reflectors which reflect
only so much light as does not pass through them thus utilizing a large portion of
the light which in ordinary lamps is wholly wasted or nearly so.
The outer
surface of each meniscus may be either parallel with the inner surface or otherwise
according as it is desired or not to bend the rays passing through.
Each meniscus is so arranged that its optical axis corresponds with the direction
in which it is desired to direct the principal illumination.
If desired instead of forming the meniscus independently of the flat glass G, G¹
in which (except in the example shown in Figures 11 and 12) it is mounted, we
may form the meniscus and flat glass in one piece by moulding stamping bending
or otherwise.
Lamps constructed as before described give much better illumination for a given
burner than those of ordinary construction for the following reasons videlicet :-
First. The intensity of the gas flame or flames is increased by the heat of the
cross rays.
Secondly. From the curved surfaces giving divergent reflection.
The meniscus may be applied to lamps of other than square form in transverse
section.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
1. Constructing transparent reflectors consisting of a disc or meniscus of a curve
substantially such as set forth in Specification of Letters Patent Number 200236
or Number 14034" for use in lamps as hereinbefore described.
2. A transparent disc or meniscus for use in a lamp whether fitted separately
or made in one piece with the plane side and so constructed as to reflect that
portion of the light which does not pass through it substantially as hereinbefore
described and for the purpose set forth.
3. In a lamp the employment of a complete pane or side comprising two or
more portions of flat or approximately flat glass a meniscus such as F, a split
frame such as 1, 13 and an outer soldered frame such as H substantially as herein
before described with reference to the accompanying drawings.
4. The combination with a gas burner of one or more discs or meniscuses such
as F and a bracket for supporting the meniscus from the burner substantially as
herein before described and set forth.
5. The combination and arrangement of parts constituting the complete lamp
substantially as hereinbefore described and as represented in Figure 1 of the
accompanying drawings.
6. The combination and arrangement of parts constituting the modified forms of
lamp substantially as hereinbefore described and as represented in Figures 8, 9,
and 10 of the accompanying drawings.
7. The combination and arrangement of parts constituting the complete device
for attachment to a lamp substantially as hereinbefore described and as illustrated
in Figures 11 and 12 of the accompanying drawings.
Dated the 16th day of October 1894.
NEWNHAM BROWNE,
Agent for the Applicants.