Improvements in or relating to Magic Lanterns
Year: 1894

page_text: Date of Application, 20th Oct., 1894
Complete Specification Lef, 22nd July, 1895-Accepted, 14th Sept., 1895
Improvements in or relating to Magic Lanterns,
1, WILLIAM HENRY TOMKINSON, of '81 Dale Street, Liverpool, in the County,
of Lancaster, Photographic Apparatus Dealer, do hereby declare the nature of
this invention to be as follows:-
This invention has reference to improvements in or relating to magic lanterns
the object being to enable the slides to be readily changed without loss of time..
For this purpose-I provide a slidé carrier.consisting of a frame of wood or other
suitable material the top and bottom members of which are grooved on their inner
sides, the grooves being of slightly greater width than two slidės. Along the
centre of these grooves there are formed still deeper grooves adapted to serve as
guidés fór a slide changer formed of thin material such as sheet celluloid horn or
steel. The top, and bottom members are secured 'together.by suitable cross bars
arranged at a sufficient distance apart near one end of the carrior to enable the
picture on, the slide to be fully exposed when placed in position between them.
Curved springs are secured within the upper and lower grooves between these
cross bars; they are secured to the rear walls of the grooves in such a manner
that they tend to press and hold a slidé. placed in front of them against the opposite
side of the groove. The wall of the upper groove is cut away on one side at the
outer end of the carrier to allow slides to be readily inserted in and removed
from the carrier. The slide changer is adapted to slide freely in the above
mentioned deep groove in the slide carrier into which the edges of the changer
take, guiding it as it is moved to and fro. The inner end of this slide changer is
provided with a turned over edge or books projecting in a forward direction and on
the opposite side of the plate at a convenient distance from its inner end is a
projecting shoulder or abutment adapted to bear against the rear vertical edge of
a slide.
The operation of changing the slides is as follows:-
Supposing one slide to be held in position between the crossbars by the springs
the slide which is to. be. substituted therefor is inserted in the outer end of the
carrier and the changer is then pushed into its guides in front of the plate.
Upon the continued movement of the changer the projecting shoulder.or abutment
on its rear side engages with the second slide and carries it along with it until
the said 'slide is in position behind' the first and in front of the springs the hook
upon the opposite side of the changer having ridden over the latter.
Upon
drawing the changer backward 'the second slide is left held in position by the
springs whilst the hooked portion of 'the changer engages with the first slide and
carries it to the outer end of the carrier.. As soon as the changer and the first
slide have been moved out of the way, the springs attached to, the rear side of the
grooves force the second slide against the opposite walls of the grooves and hold it
firmly in proper position for use.
When the changer is formed of celluloid, horn or the, like it may be employed
as a dissolver without 'completely shutting off the light from the lantern in which it
is employed.

page_text: With the above described construction the slides can be inserted and withdrawn
from the same side of the lantern.
Dated this 20th day of October 1894.
Improvements in or relating to Magic Lanterns.
I, WILLIAM HENRY TOMKINSON, of 81 Dale Street, Liverpool, in the County
of Lancaster, Photographic Apparatus Dealer, 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 has reference to improvements in or relating to magic lanterns,
the object being to enable the slides to be readily changed without loss of time.
And in order that the invention may be thoroughly understood I will describe
apparatus according thereto by the aid of the accompanying illustrative drawings,
of which
Fig. 1 is an isometric view of a slide-carrier and slide-changer according to this
invention, the changer being fully drawn out ready to receive a slide;
Figs. 2, 3, and 4 show horizontal sections taken on the line 7-8 of Fig. 1,
showing the slide-changer and slides in three different positions ;
Fig. 5 shows a vertical longitudinal section of the slide-carrier, the squares with
dot-and-dash diagonals representing two slides, one of them being in focus and the
other in the act of being inserted into the carrier; and
Fig. 6 is a cross section taken on the line 9-10 of Fig. 5, the dotted lines
illustrating the manner in which a slide is inserted into the carrier.
The slide-carrier consists of a frame of wood or other suitable material the top and
bottom members A and B of which are grooved on their inner sides, the grooves A¹
and B¹ being of slightly greater width than two slides. Along the middle of each
of these grooves there, is formed a narrow groove A' and B' respectively, adapted
to serve as guides for a slide-changer C which is formed of thin material such as
thin celluloid, horn or steel. The top and bottoni members A and B are secured
together by suitable cross-bars D arranged near one end of the carrier at sufficient
distance apart to enable the picture on a slide to be fully exposed when placed in
position between them. Curved springs E are secured within the grooves A¹
and B between these cross-bars; they are secured to the rear walls of the grooves
in such a manner that they tend to press and hold the slide placed in front of them
against the opposite side of the groove. The upper groove A' is cut deeper on
one side of the groove A at the outer end of the carrier as shown at A³ in Figs. 5
and 6, to allow slides to be readily inserted into the grooves A and B of the
carrier. The slide-changer is adapted to slide freely in the grooves A and B, in
which the edges of the changer engage, guiding it as it is moved to and fro.
The inner end of the slide-changer is provided with a turned-over edge or
hook C¹; and on the opposite side of the changer and at a convenient distance
from its inner end there is a projecting shoulder or abutment FI preferably formed
by a wooden haudle F adapted to bear against the rear vertical edge of a slide.
The operation of changing a slide is as follows:-
:―
Suppose a slide G to be held in position between the cross-bars D by the
springs E as shown in Fig. 3 the slide H that is to be substituted therefor is
inserted in the outer end of the carrier as indicated in Figs. 5 and 6, and the
changer C is then pushed along in guides, so that the projecting shoulder or

page_text: butment F1 engages with the slide H and carries or pushes it along unti
lide H is in position behind the slide G and in front of the springs E (as shown in
Fig. 3), the hook C¹ on the opposite side of the changer C having ridden over the
lide G in its forward movement. Upon drawing the changer C backward the
lide H is left held in position by the springs E whilst the hook C₁ of the changer
engages with the slide G and carries it to the outer end of the carrier (as indicated
in Fig. 4), whence it can be readily withdrawn from the grooves A and B' by hand.
As soon as the changer C and the slide G have been moved out of the way, the
springs attached to the rear side of the grooves A and B' force the slide H against.
the opposite walls of the grooves A and B' and hold it firmly in focus. Jis a
spring which is fixed in the bottom of the groove B' and at the rear side thereof,.
and which is depressed by the slide H during its inward motion, but which after
the passage of the slide H, rises and prevents the slide H from being drawn back
by the friction between it and the changer C when the latter is being withdrawn..
When the changer is formed of celluloid, horn or the like it may be employed as a
dissolver, as, being somewhat translucent, it will not completely shut off the light
from the lantern in which it is employed; it may, if desired when composed of
translucent material be of any desired tint, so as to effect the colour of the screen
as the changer is moved in front of the lens.
With the above described construction the slides can be inserted and withdrawn
from the same side of the lantern.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed 1 declare that what 1
claim is :-
1. For changing slides in a magic lantern a carrier and a changer so respectively
constructed and arranged that on the changer being moved along the carrier in one
direction it will introduce into position for use a slide that has been previously
placed in the carrier and on being moved in the opposite direction will automatically
withdraw the slide that was previously in position for use substantially as
o described.
2. A magic lantern slide carrier comprising a frame A. B having grooves A¹ B¹
and A2 B2 and springs E, in combination with a chauger comprising a plate Cof
suitable material such as celluloid and forme.! with a turned over edge or hook C¹
and shoulder F¹ the arrangement being such that the movement of the changer in
5 one direction will carry a fresh slide into position for use and movement thereof in
the contrary direction will withdraw the slide last previously used substantially as
described.
3. Magic lantern slide carrier and changing apparatus constructed arranged and
operating substantially as described in reference to the accompanying drawings.
XY
Dated this
EXYM
For the Applicant,
W. LLOYD WISE,
46 Lincoln's Inn Fields, London, W.C., Chartered Patent Agent.