Improvements in Optical Lanterns.
Year: 1892

page_text: Date of Application, 23rd Dec., 1892
Complete Specification Left, 23rd Oct., 1893-Accepted, 23rd Dec., 1893
Improvements in Optical Lanterns.
I, SAMUEL WESLEY ALLEN, M.1.M.E. 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:-
This invention principally relates to a new method of holding and exhibiting
lantern slides in conjunction with an optical lantern. The slide is held in a
revolving frame of H shape, the lower half of the H piece holding the slide when
being exhibited, and is therefore in close proximity to the condenser, and in the
centre line thereof, the light passing through it in the usual way, the upper part of
the H piece being ready for the insertion of the next slide, which is securely held
in position by small springs pressing against the face. The H piece in the centre
has a projecting spindle which runs in a bearing of suitable length, so that it can
revolve with ease, in order to bring each slide into or out of position, in front of
the condenser. The H piece is revolved by means of a haudle with a catch,
engaging in a ratchet wheel which has two teeth on its periphery so that when the
handle is pulled toward the operator, the H piece revolves a part of a circle, the
remaining part of the circle up to the angle of 90 degrees being performed by
means of a spring acting on a lever. This lever presses on two shieves or rollers
on the centre of the H piece, so that when the slide is in position, the two rollers
are horizontal with the lever pressing on both rollers.
The handle for revolving the H piece has two objects, firstly to bring each slide
in position and secondly to operate a lever arrangement for raising and lowering
a ground glass screen placed between the slide and the object glass, so that when
a slide is in position for exhibiting, the ground glass screen is down and upon
pulling the lever over, the screen is raised, this operation being performed by a
system of levers, so that a comparatively long stroke is given to the screen in
order to bring it clear out of the way of the line of light between the slide and
the object glass. Upon releasing the lever, the screen is again lowered and when
it is quite down and the picture obscured, the H piece is revolved so as to bring
a fresh slide into position and the exhibited one ready to be taken out and a
new one put into its place.
Upon the taps for regulating the oxygen and hydrogen gases, I replace the
ordinary plug with one of improved forin, the centre of this plug is drilled longi-
tudinally and fitted with a centre piu screwed to fit the hole in the plug. This pin
when screwed home fills entirely the hole that passes through the plug for the
passage of gas and when unscrewed allows the requisite quantity to pass through,
so that the plug remains as usual for opening or closing, and the regulation of the
gas effected by the pin before mentioned. A small milled head being placed on
the outside of the pin. Any ordinary tap can be altered and adapted with the
above arrangement.
The lantern itself, being of small dimensions, and very light, is designed to be
used in conjunction with an ordinary photographic tripod; the one prefer being
the "Ashford," so that when it is extended to its fullest height, and the lantern
placed and secured on the top thereof, it is of sufficient height for exhibiting
purposes, and is much more convenient than the usual way of resting the lantern
on a table or such like.
To prevent the legs from spreading and to hold the whole rigid, I employ three
round wires of about th inch in diameter, one end of each being made in the form
of an eye, and the other screwed about 4 inches in length, upon which are fitted to

page_text: each screwed end, two winged or milled nuts. The ends with the eyes are brought
together and a pin with hand nut holds them securely together.
Through the lower legs of the tripod, and near the tops thereof, I drill a hole in
each to receive the screwed ends of the wires, so that when the arrangement is in
position, the legs of the tripod cannot slip away and the whole can be moved
about without interfering with the raising or lowering of the lantern or its
adjustment.
This latter device can be used in conjunction with camera tripods for photo-
graphic purposes.
Dated this 23rd day of December 1892.
PHILLIPS & LEIGH,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Optical Lanterns.
I, SAMUEL WESLEY ALLEN, M.I.M.E. 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:-
The present invention relates to improvements in optical lanterns, more
particularly, to improved devices and mechanism for providing for the removal
of the last slide and the insertion of the next one during the exhibition of the
one in the lantern, for closing the lantern during the time that a change of slide is
being effected, for regulating the gas supply, as well as for preventing the legs of
the lantern tripod slipping outwards and for preserving the adjusted working height
of the lantern above the base of the said tripod.
Figure 1 is a side elevation of an optical lantern constructed according to the
present invention and mounted upon my improved tripod stand.
Figures 2 and 3 are details illustrating the improvements in the stand.
Figure 4 is a side elevation of the lantern illustrated in Figure 1, but on a larger
scale.
Figure 5 is a plan corresponding with Figure 4 but illustrating the use of the
reading lamp attachment.
Figure 6 is a front elevation of Figure 4.
Figure 7 is a sectional front elevation illustrating the mechanism for revolving
and locking the dissolver.
Figure 8 is a plan of the said mechanism.
Figure 9 is a sectional front elevation of the improved dissolver and of the
mechanism for working it.
Figure 10 is a longitudinal sectional elevation of my improved regulating
gas tap.
Figure 11 is a side elevation; Figure 12, a front elevation; Figure 13, a plan;
and Figure 14, a perspective view, all illustrating an alternative mechanism for
revolving the slide carrier and working the dissolver.
Figure 15 is a sectional side elevation of the lever of the said alternative
mechanism.
Referring to the first part of my invention, a is the slide carrier. It is a frame of
light metal or other suitable material, and consists of two sides and a central cross
piece which together present, in front elevation, the appearance of an H. In
respect of the cross section of the material of which the said sides and cross piece
are made, one is selected proper for receiving and holding slides; and suitable
spring fingers are added when desirable. Each carrier is, in virtue of the cross piece,
a duplex one, i.e., it is capable of holding two slides, one on each side of the cross
piece, and foot to foot, because the carrier is made to revolve in its vertical plane
about an axis which, is parallel with and vertically above that of the condenser.

page_text: 6 is the axis in question. It is a horizontal rod adapted to turn in a long bearing b¹
fixed on the body of the lantern. c, c' are the two slides in the carrier. The lower
one is in position for being exhibited. The upper one has just been exhibited and
is waiting to be taken out of the carrier and replaced by another, or it has just
been inserted in the carrier and will be brought, by the next half turn thereof, in
front of the condenser. d, are two rollers mounted upon axes projecting from
the front face of the carrier a. They are equidistant from the axis of the latter
and stand with the tops of their peripheries in the horizontal plane (in which also
stands the top of the bearing already described) when the frame is vertical.
e, el are two arms at right angles with each other. They are fast to each other by
a connecting piece by which they are made capable of being moved together about
an axis in a bearing e aligned near one side of the lantero body. The arm e is
long enough to lie across both rollers d, d. The arm e¹ is much shorter and stands
up from the lantern body when the former is down upon the rollers d, d. e is a
spiral spring. One end of it is made fast to a fixed point on the lantern body
opposite to the arm el, and its other end to the latter, so that the tension of the
said spring always tends to keep the arm e down upon the rollers d, d', with the
result that the carrier a is locked in the vertical position at the end of each half
turn. The tension of the spring is preferably adjustable.
The slide carrier is revolved for the purposes of raising the last slide out of the
lantern body, of putting the next one in front of the condenser and of giving the
operator an opportunity of inserting a fresh slide in place of the said last one, as
well as of working the dissolver by the following mechanism. f is a lever having
a forked end which is bored transversely to pass over the rod 6 which serves as
a fulcrum for the lever. 1 is a ratchet wheel fast. on the said rod within the
fork is a spring pawl on the lever fand in constant engagement with the
periphery of the ratchet wheel. The latter has the same number of steps as
the carrier has slides, the steps being, like the latter, opposite to each other.
f* is an opening in the top of the referring to Figure 9-left side of the
lantern body. g is the dissolver. It is made of any suitable material and is fixed
in a frame g. It is provided for the purpose of being dropped in front of the
condenser and kept there while the slide carrier is being revolved. There is a
transverse slot in the top of the lantern body through which the dissolver is
alternately dropped and raised. A is a lever behind the dissolver. It has its
fulcrum in a socket a fast on the left side of lantern body. Its outer end is
cranked to the front so as to act as a support for the dissolver which it carries
by standing under the arch of its frame g to which it is, preferably, pivotted.
is a third lever having its fulcrum in a socket fixed upon the top of the
lantern body about half way between the opposite side of the lantern body to
that on which the lever h' has its fulcrum, and the fulcrum of the lever f. This
third lever stands beneath the lever and its front end is cranked forwards so
as to stand under the lever with which it is connected by passing the front
and cranked end of it through a socket fast transversely upon a sleeve h* loose upon
the lever is a spiral spring between it and a fixed point in the said lever
between the spring and the outer end of the lever. is an antifriction roller
carried on a transverse axis in an extension of the lever f and on the opposite
side of its fulcrum. The said roller stands in the same plane as the lever and
under it. The levers above mentioned are parallel with each other, as are, likewise,
the fulcra and axes.
The full lines of Figure 9 shew the respective positions of the parts when the
dissolver is up-the bottom slide being then on exhibition-and the dotted lines,
the respective positions when the dissolver is down in front of the condenser. The
When the said
dissolver is raised by pulling the lever over from right to left.
lever is nearly over to the left, the roller engages the lever / near to its fulcrum
aud causes it to raise the dissolver suddenly. Before the roller / engages the
lever, the pawl will have engaged the top step on the ratchet wheel f¹ and
caused the latter to revolve the shaft o of the slide carrier through half a revolution.

page_text: The necessity for effecting the change of slides before the rise of the dissolver is
the reason why the lever is made to move through, comparatively, so considerable
a portion of its arc before it engages the lever . When the said step on the
ratchet wheel is under the shaft b, it is engaged by a spring tooth, as shewn by
the full lines, for the purpose of preventing the said wheel being moved by the
return motion (next described) of the lever f. Provision is made for holding
the lever down in the "dissolver raised" position by a suitable spring catch ³.
When the lever f is pushed over to the right through its return motion, the
roller is moved away from under the lever h² so that the weight of the dissolver-
the latter being then unsupported-drops it in front of the condenser again. The
drop of the dissolver is assisted by the expansion of the spring 4 forcing the
sleeve along the lever ³. The pawl moves smoothly over the periphery of
the ratchet wheel and drops behind the then top step of the latter. It is to be
noted that the last mentioned motion of the leverf does not affect the position of
the slide carrier because there is not during it any engagement between the lever f
and the rod b.
Referring to Figures 11 to 14, the alternative mechanism for revolving the slide
carrier and working the dissolver is as follows. is the principal lever; f', its
ratchet wheel; and f the fork. i is a tooth working in an axially inclined bore in
the head of the fork from which it is protruded by a spring for the purpose of
being kept in contact with the periphery of the said wheel. jis the dissolver. It
is are shaped. is the slit in the top of the lantern body through which the
dissolver is dropped and raised. is the lever to which the dissolver is fixed.
It has its fulcrum parallel with and near-referring to Figure 12-the left side of
the lantern body. ³ is a spring arm fast by one end to the fork 3,-the point of
fixation being near the axis of the lever and normally standing away from it.
Its opposite end carries a finger which stands clear of the lever when the
dissolver is down. is an incline made in the rear face of the lever near to its
fulcrum and in the path of the finger when it is being moved in that direction.
When the lever j is down upon the top of the lantern, there is room at the foot of
the incline for the said finger to spring under the said lever. is a stop fast on
the underside of the lever in a proper position for limiting the motion of the
lever to the left until the dissolver has been dropped.
The lever is either short enough for the finger to clear it when the latter is
down on the top of the lantern body, the lever being then over to the right, or a
notch is cut near the outer end of the lever . This latter arrangement is
illustrated in the dotted lines in Figure 13.
The dotted lines of Figures 12 and 13 illustrate the position of the parts when
the dissolver is down in front of the condenser, and the full lines, the opposite one.
When the leverf is in the position illustrated in the dotted lines, the finger i is
in engagement with the right hand step of the ratchet wheel, and the finger clear
of the lever. The lever f is pulled over to the left as far as it will go (thereby
moving the slide carrier through half a revolution), the finger then sliding
down the incline 2 and being pushed under the lever by the spring arm. The
dissolver is raised by moving the lever f from left to right. As the contact
between the finger and the lever commences close to the fulcrum of the latter,
a short motion of the lever fsuffices to raise the dissolver from before the condenser,―
as far as will take the said finger to the right of the stop 7. The latter will then
serve as a lock for the lever f. The dissolver is dropped by completing the motion
of the last mentioned lever to the right.
The slide carrier a is locked in its terminal position by the entrance of a spring
bolt into a respective hole in the carrier, under the resilience of a spring k².
The bearings for both the slide carrier and the dissolver are mounted upon a
plate which can be moved farther from or nearer to the condenser, upon studs¹
which pass through slots in the plate into the lantern body. This adjustability in
point of position of the plate 1, is adapted to provide room for the mechanical
effects or other apparatus between the slide carrier and the condenser.

page_text: The second part of the present invention is illustrated in Figure 10. v is
the cock plug. It is shewn as full open. ' is the port through it.
The plug v
is bored out axially from its head up to its port and screwed to receive a threaded
pin which works through a nut in the head of the plug. The nose of the
pin vis conical and a corresponding cavity is cut in the side of the port
opposite the axial bore of the plug to receive it. The quantity of gas passing
through the port can be regulated to a nicety by adjusting the position of the
nose of the pin v³.
The third part of the present invention is illustrated in Figures 1 to 3.
,, are three rods each having an eye ¹ at one end. Through these three eyes
laid one upon the other, there is passed a screwed pin r³ provided with two
nuts, adapted, by their approximation, to hold the eyes close together and
with their respective rods radiating at equal angles. The opposite end of each rod
is screwed for a sufficient distance and provided with two nuts, . Each end
receives its nut a, is then passed through the respective leg of the tripod and
has its outer nut ³ screwed on. When the last mentioned pairs of nuts have been
adjusted and tightened, the tripod, and lantern too, can be moved about without
interfering with the adjusted working height of the latter above the base of the
former.
The reading lamp attachment is as follows. is a door hinged to the side of the
lantern body by the side of the light. It is intended to be opened till it stands at
an angle of less than a right angle with the side of the said body and is provided
with wings pl, p' which are hinged to it. The door then serves as a deflector of
the light while the wings prevent dispersion. This combination of deflector and
wings is intended to be used to throw light upon a book of the words, or the like.
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 combination with an optical lautern, of the revolvable duplex slide
carrier, as and for the purpose set forth.
2. The combination with an optical lantern, of the revolvable duplex slide
carrier, dissolver and mechanism for operating the two in harmony, as and for the
purpose set forth.
3. The combination with a gas supply pipe of an optical lantern, of the device
for regulating the said supply, as set forth.
4. The combination of optical lantern, tripod with the device illustrated and
described for preserving the adjusted working height of the lantern above the base
of the tripod, and the reading lamp attachment, as set forth.
Dated this 23rd day of October 1893.
PHILLIPS & LEIGH,
22, Southampton Buildings, Chancery Lane, W.C.,
Agents for the Applicant.