Dioptric Appliances for Lamps.
Year: 1892

page_text: COMPLETE SPECIFICATION.
Dioptric Appliances for Lamps.
I, AUGUSTE NIEUWENHUYS, of 2 Rue de l'Activité, Brussels, Belgium,
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 :-
This invention relates to dioptric appliances for lamps of various kinds, which
appliances have for their object to increase the brightness and steady the vacillating
light of flames of lamps more particularly such as are used under unfavourable
conditions, by concentrating and projecting in the required direction, the luminous
rays emitted by such flames.
The appliances are of particular utility in the case of street lamps (more
particularly those lighted with oil) and of other lamps in exposed spaces, such as
in parks, railway stations, workshops, and the like, a particular construction thereof
being specially applicable to railway carriage lamps.
On the accompanying drawings
Fig. 1 shews a vertical section of a street lamp lighted with petroleum, arranged
to be combined with the said dioptric appliance or projector.
Fig. 2 shews a plan view of the support for the dioptric appliance in the
lantern.
Fig. 3 is a vertical section of a form of dioptric appliance or projector for a
railway carriage lamp applicable either with an oil or a gas flame.
Fig. 4 shews a section of a modified form of the dioptric appliance shewn in
Fig. 3.
As described in a previous Patent of mine the dioptric appliance shewn at
Fig. 1 consists of an annular lenticular glass the vertical section of which is
lenticular or plano convex for the effective refraction of the source of light which
is placed in or near the focal centre, while the external configuration on plan may
vary according to the conditions of illumination required.
As such dioptric appliances are of considerable weight, certain difficulties arise
in suitably supporting them, particularly when they have to be used in combination
with an oil lamp.
After numerous experiments I have found that the best means of effecting this
without interfering with the distribution of light is to support both the lamp and
the dioptric appliance by means of a stand fixed at bottom to the framing of the
lantern and arranged as shewn at Figs. 1 and 2. The stand consists of four metal
arms M fixed together at the middle by a ring A, the lower ends being screwed to
the lantern frame, while the upper ends are formed into seats or claws on which
rest the dioptric appliance P, the lamp L being suspended between the supports M
by the connecting ring A. Instead of four supports M there may be only two or
three, or there may be more than four, and the upper ends may also be connected
by a ring which would form the seat for the dioptric appliance P.
The reservoir of the lamp L may be provided with three studs e which fit into
corresponding recesses formed on the ring A so as to ensure the exact central
position of the flame relatively to the dioptric glass P, the said studs e being
passed up through notches e¹ in the ring when introducing the lamp from below
through the bottom hinged flap of the lantern. The lighting can be effected
without removing the lamp glass or dioptric glass by introducing a lighter through
the chimney glass. The described support for the dioptric glass can, of course,
also be employed when gas or other illuminant is employed instead of an oil lamp,

page_text: When
in which case the gas burner may be supported by the supply pipe either passing
up centrally from below or from any convenient part of the lantern above.
An electric incandescence lamp may also be employed in like manner.
the lamp is employed in protected positions, the dioptric glass P, carried by its
support as described can be employed without the lantern.
When applying the dioptric glass to railway carriage lamps, it is made to
surround the ordinary glass globe as shewn at Fig. 3 a much more intense and
steadier light is thus obtained, enabling travellers to read easily without straining
the eyes.
L is the lamp of ordinary construction, introduced through the hood C; G is
the ordinary globe, which is surrounded by the dioptric glass or projector A B,
suspended by a flange r in a circular groove m.
In order to effect concentration of light, the walls of the projector must be of
lenticular form such that the light is projected and concentrated in all directions,
it is therefore necessary to combine several lenticular bodies, the surface of the
whole of these being approximately that of a sphere concentric with the flame or
illuminant.
In the present example the problem is solved by combining a lenticular convex
ring A somewhat conical in section with a horizontal convex lens B forming the
bottom, the whole being a kind of globe which can easily be made in one piece,
and the external spherical surface of which accurately reflects all the luminous
rays in all directions, thus shedding great light throughout the compartment. It
might be objected that by the use of the projector A B, the ordinary globe G
becomes superfluous, and that the projector alone would suffice.
But there would be a serious inconvenience in suppressing the glass globe
because the heat of the lamp L would be received directly on the projector which
might be cracked thereby, particularly along the line of junction of the lenticular
ring A with the lens B, the thickness of glass along this circle being out of
proportion to the rest.
This risk is completely avoided by retaining the globe G which prevents the
heat from reaching the projector, the temperature of which remains the more
uniform as its interior is ventilated by its communication with the chimney C.
I have found that for certain sources of light the combination of the lenticular
ring A with the lens B in the manner shewn at Fig. 3 has the disadvantage of
causing the line of junction of the two parts to cast a shadow.
In order to obviate this inconvenience, I employ in such cases the construction
shewn at Fig. 4. In this case the lenticular ring A is made of a more conical
internal form, while the lens B is replaced by a simple globular portion P, of
uniform thickness throughout, like the bottom of the ordinary globe. By this
means the occurrence of shadows is avoided.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. In lanterns, the use of a stand composed of two, three or more supporting
arms M of any desired configuration so combined and arranged as to serve as
support both to the oil lamp L and the projector or dioptric appliance P, the oil
lamp being carried by the connecting ring A or equivalent device while the
projector is carried by a seat formed either by the upper ends of the arms M, er
by a ring fixed thereto, such support being also applicable for carrying the
projector, when the source of light is otherwise supported, substantially as
described.
2. For increasing the brilliancy and steadiness of the lights in railway carriages,
the combination with any suitable lighting apparatus of a lenticular projector or
dioptric appliance consisting of several sections A B united to each other or cast
in one piece in such manner that their external surfaces form approximately a

page_text: sphere, concentrating and reflecting correctly the rays of light emitted from the
source of light placed at the centre, substantially as described and shewn on the
accompanying drawings.
0
ABEL & IMRAY,
Agents for the Applicant.