Improvements in or appertaining to Apparatus for Ohanging the Views in a Magio Lantern.
Year: 1891

page_text: Date of Application, 29th Aug. 1891-Acc-pled, 7th Nov., 1891
UUNI UMIE DIEUIFICATION.
Improvements in or appertaining to Apparatus for Ohanging the
Views in a Magio Lantern.
I, CHARLES WILLIAM HUSON B. Sc. of York Buildings, Dale Street,
Liverpool, in the County of Lancaster, Analytical Chemist, 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 certain improvements in or connected with apparatus for
changing the views in magic lanterns, its object being to provide means whereby
the lens or, what is the same thing, the luminous field of the soreen upon which
the views are projected-may be more or less obscured during the changing of the
plates or transparencies in the lantern.
In carrying the invention into effect, I arrange, in connection with the plate
carrier or slide, a shield which is adapted to be operated in such manner that,
prior to the movement of the carrier to change the view, the lens is obscured and,
during the movement of the carrier, remains obscured, being again placed in an
unobscured condition after the movement of the carrier is complète. All these
movements of the carrier and the obscuring device are performed in their proper
order by the simple movement of an operating lever connected by suitable
mechanism to the carrier and shield.
One form of apparatus embodying my invention is illustrated in the accom-
panying drawings, in which-
Figure 1 is a rear, and Figure 2 a side, elevation of the apparatus.
In these--
A is a carrier capable of holding two plates as at a a³, and of sliding within a
suitable framework A', its movement being limited in either direction by stop
pins a a. The plates are supposed to be inserted at the top of the overhanging
portion of the slide or in other suitable manner.
D is a lever pivoted at E and having its lower end engaging the plate carrier A
by means of a slot and pin connection as at H, or by other equivalent device in
such manner that the swinging of the lever about its pivot effects the reciprocation
of the slide:
B is a second or operating lever pivoted at C, the position of this pivot
being preferably directly below the pivot E at a suitable distance therefrom, as
shown.
one.
F is a rod mounted upon the axis of the pivot C and movable with the lever B,
the connection between the said lever and rod being, by preference, a detachable
The rod may be made telescopic for the purpose of adjusting its length to
suit that of lens tube. The rod is provided at the end remote from the lever B
with a shield G fixed upon or within a holder G' which is attached in any suitable
manner to the rod.
The lever D is provided with a T-shaped head D₁ furnished at its ends with
stop pieces dd', and at its centre with a notch d. b is a pin projecting from the
lover B past the upper edge of the lever head D.
The relative positions of the pivots C and E and the configuration of the
upper edge of the lever head D' are such that, when the lever B is moved from
its extreme position, as shown in Figure 1, towards the right, the pin b does not
engage the lever head D' until it comes in contact with the further edge of the
notch therein. This portion of the movement of the lever B places the shield G
in such a position as to obscure the lens. Continuing the movement of the lever
towards the right, the lever D moves along with it, the plate carrier being
thereby slid from the right to the left und the plate at a¹ being thus brought into

page_text: position. The shield G is of such a shape and size that it obscures the lens during
the whole of the movement of the carrier. The movement of the latter being
now complete, the further movement of the lever B to the right takes place
without a corresponding movement of the lever D and effects the removal of the
shield from the lens.
the
In the extreme positions of the lever B, the pin b rests against one or other of
stops dd' of the lever head D', the travel of the latter being limited by the
stops a a³. To reverse the carrier, the above cycle of operations is gone through
in the reverse direction..
The shield holder G₁ is preferably so attached to the rod F that it can, when
desirable, be swung aside so that it offers no obstruction to the rays from the lens
and also affords facilities for packing when the rod is detached from the
lever B. The shield G is, by preference, made of ground glass celluloid or other
translucent material.
It will be obvious that other modified arrangements may be provided whereby
the lever B shall only operate the lever D during the middle portion of its
movement. The above will, however, serve sufficiently to illustrate the nature of
the invention and the manner of carrying it into effect.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what I
claim is :-
:-
1. In conjunction with the plate carrier of a magic lantern and with a movable
shield for obscuring the leus thereof, mechanism connected with said plate carrior
and shield and so combined and arranged that, during the middle portion of the
travel of an operating lever, the lens is obscured by the shield and the carrier
operated, while, during the initial and terminal portions of said lever's movement,
the shield is moved to respectively obscure and unobscure the lens without a
corresponding movement of the carrier, substantially as described.
2. The combination, with the plate carrier and the revolving shield, of the lever
movable with the carrier and the operating handle movable with the shield and
80 mounted and arranged with respect to said lever that it is automatically
coupled to the latter during the middle portion of the stroke and uncoupled
therefrom during the initial and terminal portions of its stroke, substantially as
and for the purposes described.
3. The improved apparatus for temporarily obscuring the lens of a magic
lantern, taken as a whole and combined and arranged substantially as shown and
described.
Dated this 00th 1 of 1001
WM. P. THOMPSON & Co.,
Of Liverpool, Manchester, Nottinghain, and London, Patent Agents.