Improvements in Shutters for Optical Lanterns.
Year: 1890

page_text: COMPLETE SPECIFICATION.
Improvements in Shutters for Optical Lanterns.
GEORGE SAMUEL THOMPSON of 5 Farleigh Road, Stoke Newington, in the County
of Middlesex, Carriage Builder 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 :-
Fig. 1 illustrates a complete form of the automatic combination shutter as adapted
to a triple lantern, and consists of Figs. 3, 4, 5, and 6.
Fig. 2 is a drawing of the front elevation of a triple lantern having the front
stages and tubes removed, and the guide (Fig. 8) attached to the hinged front above
the top condenser by milled-head screws E. E.
The spaces in the lantern fronts, immediately in front of the condensers, between
the dotted lines F. F, are for the passage of the shutter, as also is the slot cut
through the baseboard and denoted by the dotted lines G. G.
The dotted lines H. H. mark the position of a small groove for reception of the
stud I in Fig. 4.
Fig. 3 is the diaphragm A, and is provided with either a lip or wooden handle J,
for convenience in lifting.
Fig. 4 is the diaphragm B, on each side of which are two small lugs K. K. adapted
to slide very freely within grooves provided for them in the shafts of Fig. 5.
A small stud I projects from the back of the diaphragm B, sufficiently short that
when the shutter is in the lantern front it quite clears the condenser lens when
sliding over it and also passes freely down the groove H. H. Fig. 2 until the
diaphragm B is immediately below the top condenser, in which position the stud
comes in contact with and rests upon the stop formed by the termination of the
groove H. H.
Fig. 5 is the diaphragm C with two shafts attached, each of which has a
groove L. L. with its opening towards the other, and extending throughout the
length of the shafts, forming a free passage for the lugs K K, thereby allowing B to
slide between A and C when the shutter is in the lantern.
Throughout rather more than two-thirds of the entire length of Fig. 5, a rack is
attached which by the aid of the pinion M Fig. 2, the shutter may be moved up and
down.
Fig. 6 is the diaphragm D with two shafts attached without grooves or rackwork,
and is suspended from Fig. 5 by two small studs or clips at N N as shown in Fig. 1,
or if so desired Fig. 6 may be permanently fixed to Fig. 5.
Fig. 7 is an enlarged section of the shafts of Fig. 5, P being the rack.
Fig. 8 is the shutter guide and is provided with grooves QQ with their openings
towards each other, for the guiding of Fig. 3 which slides within them. A hinged
bracket R is attached as shown for the purpose of supporting the diaphragm A when
required as hereinafter described.
Fig. 9 is an enlarged cross-section of the shutter guide and bracket (Fig. 8).
If the automatic combination shutter be inserted in the triple lantern, and brought
to the relative height indicated by the dotted lines SSS connecting Figs. 1 and 2,
the top line of the diaphragm B and the bottom lines of C and D will, in a vertical
direction, coincide respectively with the top, centre, and bottom condensers, and,
moreover, the bottom line of the diaphragm A and the top lines of C and D will
coincide respectively in their vertical relationship with the top, centre, and bottom
condensers.
In this position it is apparent that the light that would otherwise emanate from the

page_text: top condenser is cut off by the diaphragm B, 'while the light from the middle and
bottom condensers are unaffected by the shutter.
By imparting a downward movement to the shutter by means of the pinion M, the
top condenser is gradually opened from the top, thereby allowing the rays of light to
escape, simultaneously with which, and in parallel lines, the rays of light from the
centre and bottom condensers are gradually cut off from the same direction, causing
a rolling up effect from 2 optical systems into one.
Until, hy
a continued movement, the shutter is brought to the position shown in
Fig. 10, in which the centre and bottom condensers are entirely covered by the
diaphragms C and D and the top one is open.
It is now optional to the operator either to produce a rolling down effect, to open
all three condensers, or to produce another rolling up effect.
If the former is required it is necessary only to reverse the operation, viz.―by
raising the shutter.
It it be desired to open all 3 condensers, it will be necessary to first lift the
diaphragm A and support it by the hinged bracket R, and then lower the shutter to
its fullest extent, and the result will be as shown in Fig. 12.
But if instead of either, it is wished to cause a second rolling up effect, it
is merely necessary to continue to lower the shutter in the same way as at first, the
result of which will be the cutting off of the rays of light in top condenser from the
top, simultaneously allowing the rays to escape from the centre and bottom condensers
in the same direction, thereby causing a rolling up effect from one optical system into
two, until the centre and bottom condensers are open and the top covered by A as
shown in Fig. 11.
The diaphragin A may then be lifted up leaving all three condensers open as in
Fig. 12 for convenience of dissolving and the shutter left in position for either one or
two rolling down effects, to be made at the will of the operator.
The automatic combination shutter is of course applicable with any number of
optical systems, and several modifications may be made within the meaning of my
invention.
For a bi-unial lantern the diaphragm D is not required, and even with a triple
lantern a shutter in this form is exceedingly advantageous.
Its application to a bi-unial lantern may be seen by reference io Figs. 2, 10,
11, and 12, the dotted lines T. T representing the position of the baseboard through
which it is necessary to have a slot for the passage of the diaphragm C.
The working of the shutter in this form is practically identical with that already
described. It is capable of producing two rolling up effects in succession, after
which both condensers may be opened for dissolving purposes, while the shutter is
left in position ready to produce two rolling down effects if required, or both
condensers may be opened after one of either up or down effects, as with the triple
lantern.
A simpler modification of the automatic combination shutter, applicable to both
triple and bi-unial lanterns is made without the use of A as well as without D, in
which it follows also that there is no need for the shutter guide.
The movement is applied from the pinion in the same manner as the others already
described, but one rolling up effect only can be produced, after which the closed
optical system may be opened, leaving the lantern clear for dissolving, and the shutter
remaining in position for producing one rolling down effect.
This form of shutter may also be made as Fig. 13 to work by the handle J instead
of the rack and pinion.
A shutter may also be made in the form of Fig. 14, which is similar to Fig. 13, but
has the diaphragm A attached, and may be worked either by rack and pinion or by
hand. It is suitable for triple lanterns. With this, either one or two rolling up
effects may be produced, but if two be produced in succession it is necessary to dissolve
into the bottom optical system before all three can be opened.
The principle of my invention is also easily applied to side-by-side lanterns.

page_text: 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. The plan and arrangement of sliding diaphragms, for magic and other optical
lanterns, or combinations of lanterns, having two or more optical systems, whereby
rolling up effects and rolling down effects may each be produced twice in succession.
2. The arrangement for a triple lantern whereby the effect of a curtain rolling up or
down may be made, cutting off the light from two optical systems, appearing from
one, and vice versa.
3. The arrangement whereby, after the production of either one or two rolling up
effects, from a combination of two or more optical systems, every optical system can
be opened free for dissolving purposes without removing the shutter from the
lantern or causing a rolling down effect.
4. The arrangement with lanterns of two or more optical systems, whereby after
all optical systems have been open for dissolving purposes, one or two rolling down
effects can be produced without having either to insert the shutter in the lantern, or
produce a rolling up effect.
Dated this Fourteenth day of November 1890.
G. S. THOMPSON,
Applicant.