Improvements in Optical Lanterns.
Year: 1889

page_text: Date of Application, 20th Nov., 1889
Complete Specification Left, 20th Aug., 1890-Accepted, 20th Nov., 1890
Improvements in Optical Lanterns.
I, ALEXANDER HUGHES, of 59 Fenchurch Street, in the City of London, Optician,
do hereby declare the nature of this invention to be as follows:-
My invention relates to that class of lanterns generally known as "optical lanterns,"
such as those used for projecting views upon screens by means of artificial light.
This invention is particularly applicable for lanterns of the triunial, biunial, or single
type used for producing dissolving views.
My invention consists in the construction and arrangement of the lanterns in triple,
double, or single from whereby the following advantages are obtained over the lanterns
now in use viz. :-
1st. When triple or double lanterns are used of the ordinary description, only one
set of lenses with condensers and lighting apparatus are working upon the true
optical centre, for assuming that the centre set of lenses is the one working as
described above, the lenses of the upper and lower lanterns have to be inclined to
the other lanterns in order that they shall project the image upon the same part of
the screen as the centre lantern, this is usually effected by throwing the front set,
or objective lenses of each top and bottom lantern out of the optical centre in relation
to its condenser, causing distortion of the picture, and destroying the sharpness of
detail on one part or other of the picture.
These evils are entirely obviated by my invention as each optical system or lantern
is complete and independent in itself, and can be tilted to any convenient angle as a
whole as may be required.
2nd. Considerable reduction in cost of construction is attained owing to the simplifi-
cation of design.
3rd. The weight is very greatly reduced and much less space occupied by the
lantern as a whole.
I carry out my invention in the following manner :-
Upon a stand preferably the top of the box within which the lantern is kept I
provide two stiff uprights of metal, wood or of any other suitable material which may
be round, square, or any other convenient shape.
The bottom frame or base board of the lantern may consist, preferably of wood within
which slides a second frame, of wood or metal.
Upon one end of the base-board I fix a supporting frame, holding the condenser,
upon the front side of which any ordinary arrangement for retaining the slide in
position is made.
Upon the movable frame which slides within suitable grooves on the base-board
provide an upright frame carrying the objective lens. A set of leather bellows of
round, square, conical or parallel form is arranged between the frame holding the
objective lens, and the frame holding the condenser.
Suitable means of adjustment are provided either by a rack and pinion movement,
or any other suitable means, for adjusting the focal distance required.
The light box at the back I preferably form of charcoal-iron, brass, or other
suitable material, of a dome-section at the top, the slides projecting downwards and
overlapping the edges of the bottom frame of the lantern.
In the sides of the overlapping edges suitable slots are provided, through which
crews are introduced into suitable holes in the base board to retain the light in position
when placed at the proper distance from the condenser.
As such a system of parallel adjustment is set up between the condenser and the
ource of light I attach in a fixed manner the lamp, or other lighting apparatus either
n the shape of an oxy-hydrogen lime light burner, an electric lamp or lamps burning
nineral oils upon the bottom plate of the light box, so considerably reducing the cost
| Duin I

page_text: of the lighting apparatus in comparison with that used at the present time and rendering
the light very much easier of manipulation.
The light box is made so that it shall overlap a projection, which is carried on the
frame holding the condenser, such projection being of such a length as to allow of
the requisite range of movement to comply with the greatest and smallest distances of
the source of light from the condenser required.
Upon each side of the condenser frame and fixed firmly to the lantern base-board
is arranged suitable fittings having set screws or other tightening arrangements.
These fittings may have a hole passing through them and are threaded over the
projecting uprights upon the top of the box as herein before described.
These fittings may be so arranged to the sides of the lantern that they shall turn
upon a pivot in such a manner so that when the lantern is threaded on the apparatus
any desired angle of elevation, or otherwise can be given to the lantern as a whole
and clamped, or fixed in that position by the set-screws or tightening arrangement at
the side as hereinbefore described and in conjunction with the brass stays hereafter
described.
It is very obvious that three separate lanterns as described can be mounted upon the
upright supports so as to form a triunial lantern.
Upon the frame carrying the objective lens or any other convenient part of the
lantern I provide suitable fittings turning on pivots, into which said fittings engage tele-
scopic stays or guide rods attached at their lower ends to the stand or box with set or clamp
screws to fix them when adjusted, the outside tube of the telescopic stays may have
grippers or other suitable fixing device arranged which shall grip the inside tubes.
When for instance the lower lantern has been allowed to rest upon the top face of
the supporting stand, or box the second lantern can have its angle set in relation to
the lower lantern so as to cover the same portion of the screen and be kept in that
position by the telescopic stays in the front, the same method is of course adapted
with the top lantern.
Great saving in weight is effected by using the bellows attachment which gives
very considerable range of the focal distance, again, the material used is much lighter
than the telescope tubes usually made of brass that are now used in lanterns and
which make the said lanterns very heavy in the front part,-in which part there is
no support to carry such weight, and also occupying considerable space when
packed up.
My lantern when required to be packed away closes up into a very small space
by racking it in, so that the front frame is brought against the condenser frame, in
a similar manner as an ordinary bellows camera.
1 may instead of using the sliding frame engaging in grooves in the base board
for carrying the frame holding the objective lenses, arrange two tubes fitted to either
the base board, or to the front frame, parallel to one another, and so arranged as to
slide within suitable sockets with gripping attachment, thus forming a very cheap
and efficient means of parallel adjustment for the front objective lenses.
My lantern as thus described will allow of all the various mechanical effects
and slides now being used in the present form of lantern, being fitted to and
worked in it, and will adjust to show pictures from the smallest up to the largest size.
Dated this 20th November 1889.
FELL & WILDING
1, Queen Victoria Street, E.O., Agents for the Applicant.
1, Queen Victoria Street, E.O., Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Optical Lanterns.
I, ALEXANDER HUGHES, of 59. Fenchurch Street, in the City of London, Optician,
do hereby declare the nature of this invention to be particularly described and
ascertained in and by the following statement :-
My invention relates to that class of lanterns generally known as "optical lanterns"
such as those used for projecting views upon screens by means of artificial light.

page_text: This invention is particularly applicable for lanterns of the triunial, biunial, or
single type used for producing dissolving views.
My invention consists in the construction and arrangement of the lanterns in triple,
double, or single form whereby the following advantages are obtained over the lanterns
now in use.
First. When triple or double lanterns are used of the ordinary description only one
set of lenses with condensers and lighting apparatus work upon a true optical axis.
Now assuming that in a triunial lantern the centre set of lenses is the one working
as above described the lenses of the upper and lower lanterns have to be inclined to
the centre lantern in order that they shall each project the image upon the same part
of the screen as the centre lantern.
This is usually effected by throwing the front set or objective lenses of each top and
bottom lantern out of the optical centre in relation to its condenser thus causing distor-
tion of the picture and destroying the sharpness of detail in one part of the view or the
other.
These disadvantages are entirely obviated by my invention as each optical system or
lantern is complete and independent in itself and can be tilted to any convenient
angle as a whole with one or other lantern as may be desired.
Secondly. Considerable reduction in cost of construction is obtained owing to the
simplification and compactness of the design.
Thirdly. The weight is greatly reduced as the material used in construction may
be aluminium, also much less space is occupied by the lantern as a whole.
Fourthly. My lantern will allow of all the various mechanical effects and slides now
being used in the ordinary form of lanterns being fitted to it and worked and the adjust-
ments are arranged so as to permit of the projection of pictures from the smallest up
to the largest size without further apparatus or adjuncts to the lantern.
In order that my invention may be the better understood I now proceed to describe
the same in relation to the drawings hereunto annexed reference being had to the
letters and figures marked thereon.
Like letters refer to like parts in the various figures.
Figure 1 shows in side elevation partly in section two lanterns constructed and
mounted according to my invention.
Figure 2 is a front end view of the same.
I carry out my invention in the following manner :-
Upon a stand A preferably the top of the box within which the lantern is kept I
provide two stiff uprights B of metal, wood, or any suitable material which
may be round, square, or any other convenient shape but preferably tubular.
The bottom frame or base board of the lantern consists preferably of a metal
frame in the form of a box in order to give considerable stiffness.
Upon this frame C at the front end 1 arrange a second frame D standing on end
within which the condenser d is supported.
Upon the front side of the condenser frame any ordinary arrangement E for
retaining the slide in position is provided.
Between the front and back vertical sides of the bottom frame or base board two
tubes F preferably of metal are supported parallel to one another.
Into these tubes engage two other tubes G of such a diameter as to permit a good
sliding fit, these latter tubes being fixed to a vertical frame or plate H carrying the
objective lens J.
The lower part of these sliding tubes have suitable teeth cut upon them into which
teeth gear a pair of revolving pinions K situated on one spindle L which is supported
at right angles to the tubes F, a suitable aperature being made in the fixed tube
through which the pinion works in order to engage with the teeth on the interior
tube.
A set of leather bellows M of round, square, conical, or parallel form is arranged
between the frame H holding the objective lens and the frame D holding the condenser
& the slide retaining frame, E.

page_text: The light box N at the back I preferably form of charcoal, iron, brass, or other
suitable material and as the direction of the heat with the oxyhydrogen lime-light
burner is in an angular direction upwards towards the back of the lantern I form the
top or roof of the light box so as to be hinged from the front part thereof. When
closed down for transit the light box is square but when required to be used the top
or roof is hinged up around its pivot or hinge m so as to form a slanting roof with
the highest part at the back of the box, the sides of this movable roof or top project
downwards and lying in close proximity with the sides of the light box, the end
being formed cylindrical with the pivot or hinge as the axis.
Suitable apertures P and baffle plates p are provided at the top angle in order to
permit of perfect ventilation without allowing the light to escape.
The sides of the light box project downwards and overlap the edges of the bottom
frame of the lantern.
In these projecting sides suitable slots are provided through which screws are
introduced into holes in the base board, the object of these screws R being to retain
the light and the light box in its adjusted position when placed at the proper distance
from the condenser. As such a system of parallel adjustment is set up between the
condenser and the source of light, I attach the lamp or other lighting apparatus
either in the shape of an oxyhydrogen lime-light burner electric lamp or lamp
burning mineral oils in a rigid manner upon the bottom plate of the light box so
considerably reducing the cost of the lighting apparatus in comparison with that used
at the present time and rendering the light very much easier of manipulation. The
light box is made so that it shall overlap the end of the frame holding the condenser
or equivalently a projection extending therefrom, such frame or projection being of
such a length as to allow of the requisite range of movement to comply with the
greatest or smallest distance of the source of light from the condenser required.
Upon each side of each lantern I arrange a swivel attachment S which is capable
of being threaded upon, or attached to the vertical supports B carried by the lid A of
the lantern box.
These attachments have a set screw s or other equivalent tightening arrangement in
order to securely fix the lantern in any position on its supports provision being made
in the fittings to allow the lantern to be turned around a horizontal axis in such a
manner that when the lantern is threaded on to its supports any desired angle of
elevation or otherwise can be given to it as a whole and clamped or fixed in that
position by the set screws or tightening arrangements at the sides as hereinbefore
described and in conjunction with the brass stays hereinafter described.
It is very obvious that two, three, or more separate lanterns as described can be
mounted upon the upright supports so as to form one multiple lantern.
Upon any convenient part of the frame preferably that carrying the condenser lens
I provide suitable telescopic stays T or equivalent contracting or expanding tie rods
having clamp screws t in order to adjust and firmly fix the front of the bottom lantern
to the supporting box and similarly the superposed lanterns to one another.
These telescopic stays-or-tie-rods may be pivotted at their points of attachment to
the frames of the lanterns and may be provided with grippers or other suitable
fastening device arranged so as to permit the inside tube or stay being gripped by the
outside stay surrounding it.
When for instance the lower lantern has been fixed upon the supports B and adjusted
at the proper angle by the telescopic stay T, the second lantern is adjusted so that it
shall have its angle set in relation to the lower lantern in order to cover the
same portion of the screw and be kept in that position by its telescopic stay T in
front.
The same method is of course adopted with the third lantern when three are
used.
It is obvious that a great saving in weight is effected by using the bellows attach-
ment which gives very considerable range of focal distance and also the material used
is much lighter than the telescopic tubes (usually made of brass) that are now used in

page_text: ordinary lanterns which make the said lanterns very heavy in the front where there
is no support to carry such weight, the tubes also occupying considerable space when
packed up for transit.
My lantern when required to be packed will close up into a very small space by
racking it in so that the front frame is brought against the condenser frame in a
similar manner as an ordinary bellow camera. I also attach considerable importance
to the fact that the design of my lantern will permit of its being almost entirely
made of aluminium in order to greatly reduce its weight.
Having now particularly described and ascertained the nature of this said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1st. The construction and arrangement of hiunial, triunial, or other multiplex
optical lanterns in which each optical system is so mounted as to permit of the
adjustment of each lantern one to another without distorting the optical axis of the
one or the other.
2nd. A multiplex optical lantern in which each lantern system is adjustably
mounted and pivotted on vertical supports for angular adjustment and retained in
position by telescopic or adjustable supports attached to each lantern.
3rd. The construction and arrangement of an optical lantern allowing parts
of it being manufactured of aluminium to reduce the weight substantially as
described.
4th. In such an optical lantern a light box so constructed that the roof or top
shall fold down for transport and capable of being raised by a radial movement around
its centre in an angular direction to permit the better ventilation and carrying off of
heat substantially as described.
D 11
T
CA
1000
FELL & WILDING,
1, Queen Victoria Street, London, E.C., Agents for the Applicant.