Improvements in Optical Lanterns.
Year: 1895

page_text: Improvements in Optical Lanterns.
I, SAMUEL WESLEY ALLEN, of Exchange Buildings, Bute Docks, Cardiff, in
the County of Glamorgan, Consulting Engineer, do hereby declare the nature of
this invention to be as follows:-
One of the objects of this invention is to provide a novel method of exhibiting
lantern slides. The slides themselves are arranged in their proper order within a
rectangular box sub-divided for its entire length with transverse divisions; between
each of the divisions a slide is placed; the box being partly open for its entire
length along the bottom. This box slides easily within an outer casing which also
supports the optical arrangement of the lantern.
Upon the top of the outside box near its centre are vertical side cheeks, attached
to which are vertical guides. These guides are made in the centre line of the entire
arrangement. The slides are pushed upwards in succession from the centre box or
chamber by means of a vertical plunger passing up through the bottom of the
outer box. This plunger has a cross-head at its lowermost part and connecting
rods operated by a crank or cranks with the spindles passing through the upright
cheeks before mentioned. When the cranks are revolved the plunger ascends
carrying with it the slide in the receptacle immediately above it, taking it into
position in the optical centre of the lantern.
Two vertical rods or guides are also attached to the cross head, these pass
upwards through the sides of the outer box and have at their topmost extremity
projecting arms which extend partly over the top of the slide so that the plunger
with the vertical guide rods are caused to descend. The slide is carried downwards
and returned into its former place.
To get any slide into position a cam is formed on the centre of the crank spindle,
before mentioned, which acts upon a pall forcing the box of slides forwards another
division, the plunger again coming up carrying with it the slide into the optical
centre as before and so on until the whole of the slides in the chamber are
exhibited.
Upon the top of the side cheeks is another spindle with a crank at its end, this
spindle has a translucent sheet that is lowered in front of the slide when each slide
is being taken in or out of position. The hook or catch is formed at the top end
of one of the connecting rods. This comes in contact with the small crank last
mentioned and holds the translucent screen or dissolver out of the way of the line
of light.
The invention also relates to an improved method of taking the heat away from
the lime light jet and consists in a metal hood sliding along the lime light tray.
This hood is open at the front to allow the light rays to pass through on to a
condenser and it being open at the top and passing through the lantern carries off
all the flame and with it the great heat usually confined in ordinary lanterns.
The apparatus can be, if necessary, worked by the lecturer from the platform by
pressing a pneumatic or other arrangement and weight attached to the revolving
crank made to cause the crank with the connecting rods and plunger to be
automatically revolved.

page_text: An indicator is placed in any convenient position on the side or top of the
internal box for indicating which slide is in position.
Dated 16th day of April 1895.
PHILLIPS & LEIGH,
Agents for the Applicant.
:
Improvements in Optical Lanterns.
I, SAMUEL WESLEY ALLEN of Exchange Buildings, Bute Docks, Cardiff, in
the County of Glamorgan, Consulting 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 :-
My invention relates to improvements in optical lanterns and the objects of it
are to provide (a.) a novel method of exhibiting the transparencies and (b.) for the
escape of the heat generated by the lamp.
Referring to the accompanying drawings, Figure 1 is a sectional elevation;
Figure 2 is a transverse section along the line a-b of Figure 1; Figure 3 is a
plan and Figure 4, a section along the line c-d of Figure 3.
.
A is a rectangular box, upon which stands.the optical portion of the lantern.
B is the body of the lantern. It contains the condenser C and the lamp D. E is
the objective or projecting lens. It is attached to a front board which is secured.
to the ends of a pair of telescopic tubes F.
The main feature of this invention is the sliding drawer or magazine chamber G
within which are placed any number of transparencies H according to the length of
the said drawer. Each transparency drops easily into its place. They are
separated from each other by transverse and equidistant divisions I for its entire
length. The bottom part of the drawer is partially open for its entire length as
shown at J, leaving longitudinal strips k, along the bottom, upon which the
transparencies rest.
The drawer filled with transparencies is made to pass easily through the outer
casing A. The bottom portion of the drawer, being partly open, allows the upward
passage of a plunger L which pushes each transparency upwards as far as the
optical centre M. The plunger L is operated by cranks N, N, and connecting
rods O, O. A crosshead P is attached to the plunger L so that when the cranks
.are revolved by the handle Q, the plunger reciprocates vertically according to the
stroke of the cranks N, N.
Guide rods R, R, are attached to the crosshead P and pass upwards through
openings in the sides of the rectangular box A. Projecting arms S, S, are secured
to the tops of the said guide rods R, R, for the purpose of forcing the transparency
downwards into its former position in the drawer G.
This drawer G is fed forward for a distance equal to that between the centre
lines of two adjacent slides, by a cam T upon the shaft of the cranks N and a
pawl U (Fig. 4) engaging with the divisions I of the drawer, the motion taking
place immediately the plunger L is in its lowest position and clear of the trans-
parency and of the drawer. It will be seen that by revolving the handle Q, the
drawer G will be fed forward by the cam T and pawl U only during a small
portion of each revolution, whilst, when the said drawer stops during the other
portion of the revolution, the plunger L carries the next transparency up into
position, and after it has been exhibited the projecting arms S, on the handle Q
being now moved from its highest position, will carry the transparency down again
into the drawer G, and so on for each transparency. A spring V is provided
(Fig. 4) for holding the transparency in position during each exposure.

page_text: A projecting hook W at the top of one of the connecting rods 0 engages with
a piu e upon the end of a lever X secured to a shaft which carries a ground glass
or celluloid screen Y. On the handle Q being moved into its highest position the
screen Y is caused to rise and disclose the transparency to the lens E, the screen Y
being allowed to fall during the time the crauk N is turned round and the
transparency removed into the drawer G and replaced by another.
Z (Figure 1) is a shield preferably made of sheet metal, and within which the
lamp or its equivalent is placed, an opening in the top conveying the flame and heat
to the outside of the lantern. Z is a line of indicator figures for showing the
number of the slide in position and Z is the index finger.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. A rectangular drawer with its complement of transparencies placed
immediately under the optical system of the lantern.
2. The feeding forward of the drawer by means of the cam arrangement herein
described, by the revolutions of the cranks N, N.
3. The raising of the slides by means of a plunger passing through the bottom
of the box.
4. The holding of the slides in position by the spring arrangement V.
5. The method of working the celluloid dissolver as herein described.
6. The application of a heat shield Z as herein described.
Dated this 13th day of January 1896.
PHILLIPS & LEIGH,
No. 22 Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicant.