IMPROVEMENTS IN APPARATUS FOR EXHIBITING MAGIC LANTERN PICTURES, PARTS OF WHICH ARE APPLICABLE TO OTHER PURPOSES." PROVISIONAL SPECIFICATION
Year: 1881

page_text: LETTERS PATENT to Ernest Webster, of Loudoun Road, and Tom Mayor
Williams, of Corbyn Street, both in the County of Middlesex, for an Inven-
tion of "
IMPROVEMENTS IN APPARATUS FOR EXHIBITING MAGIC LANTERN
PICTURES, PARTS OF WHICH ARE APPLICABLE TO OTHER PURPOSES."
PROVISIONAL SPECIFICATION left by the said Ernest Webster and Tom
Mayor Williams at the Office of the Commissioners of Patents on the
23rd December 1881.
ERNEST WEBSTER of Loudoun Road and TOM MAYOR WILLIAMS of Corbyn
Street both in the County of Middlesex. "IMPROVEMENTS IN APPARATUS For
EXHIBITING MAGIC LANTERN PICTURES PARTS OF WHICH ARE APPLICABLE TO
OTHER PURPOSES."
This Invention has for its object improvements in apparatus for exhibiting
magic lantern pictures parts of which are applicable to other purposes.
The apparatus is especially designed for displaying advertisements and the like
in shop and other windows. For this purpose we arrange a number of magic
lantern slides around the circumference of a disc to which a step by step rotation
is given so that the slides are brought, one by one in succession opposite to the
lantern and are thus each exhibited in turn for any given period say half a minute.
The slides fit into grooves in the edges of recesses cut in the disc so that any of the
slides can easily be removed and others substituted. Or the slides might be
carried by a drum with a similar movement.
The disc is driven by a weight or spring or otherwise and its movement is
regulated by an escapement actuated by a clock.. For this purpose the disc carries
on its rear face a number of equidistant pegs one for each slide. The escapement
has two arms and carries the armature of an electro-magnet through which
periodical currents are sent by a clock in a manner hereinafter described. When a
current is sent through the electro-magnet the armature is attracted thus causing
the escapement to rock on its axis, and freeing one of the pegs on the disc from the

page_text: escapement. On the cessation of the current the escapement is brought back by a
spring to its original position in time to catch the next peg and arrest the disc
which thus has a step by step motion given to it the length of the periods of rest
being regulated by the frequency of the currents. A catch is provided to hold a
peg and thus prevent backward movement of the disc. If the clock happened to
stop at the moment of sending a current so that the current instead of being
momentary was continuous the armature would not be released and would thus
allow the disc to revolve freely and would probably cause a breakage of the
apparatus. The second arm of the escapement is to prevent such an accident.
When the escapement is rocked by the electro-magnet the end of the second arm is
raised in front of one of the pegs but if the apparatus is working properly it retires
again before the peg reaches it. If however the clock stops, as above described the
arm does not retire and the peg striking against it stops the disc and prevents injury
to the apparatus. An adjustable stop is provided to regulate the angle through
which the escapement rocks.
On the
The periodical currents are sent by the clock in the following manner.
axis of one of the wheels of the clock say the axis of the second hand there is a
cam wheel which if the current is to be sent every half minute has two projections.
These projections come against a pivoted lever which is thus raised twice a minute.
The free end of the lever has jointed to it a catch which acts as a ratchet and
takes into the teeth of a ratchet wheel. The catch is free to turn through a small
angle only. As the clock goes on the cam is turned and the pivotted lever is
gradually raised against-its-spring-When the lever has reached its highest
position it clears the cam and is quickly brought back by its spring and the catch
at its end striking against one of the teeth of the ratchet wheel moves it on the
distance between two teeth. When the lever is again raised the catch at its end
comes against the back of one of the teeth of the ratchet wheel but being free in this
direction it turns on its axis enough to clear the tooth and does not turn the ratchet
wheel backwards. The axis of the ratchet wheel also has upon it the contact maker.
This consists of a disc upon whose circumference there are as many projections as
there are teeth on the ratchet wheel. A spring bears against the projections on
this disc when it is turning and completes the electric circuit and thus as before
described allows the disc carrying the magic lantern slides to turn one step, when
however the ratchet wheel is at rest the spring of the contact maker drops into a
recess between two of the projections and no current passes. This part of the
Invention is also applicable to electric clocks or in any case in which periodical
electric currents have to be sent. As the magic lantern is only used at night it is
desirable to throw the apparatus out of gear in the day time. In order to do this
there is a disc upon an axis in the clock which turns once in twenty four hours.
A portion of the circumference of this disc corresponding to the longest time
during which the apparatus will be in use is cut away. A spring actuating a
switch bears against the edge of the disc and when it comes to the recess which
has been cut away it drops into it and allowing the current to pass causes the
apparatus to commence to work. When the rotation of the disc brings the spring
to the other end of the recess the spring is raised thus breaking the current and
stopping the apparatus. In order to make the time during which the apparatus
will run adjustable we employ the following device. On the same axis as the disc
we have another disc of equal size which also has part of its edge cut away. If
the recesses on the two discs coincide then the maximum time
given but if the
second disc is turned on its axis the recesses do not coincide so that the resulting
recess is narrowed and thus the time during which the apparatus will run is
shortened.
We also arrange our apparatus so that the gas in the magic lantern is auto-
matically turned on and off at the proper time. The lever of the gas cock is
placed so that when the gas is turned off it is in front of one of the pegs on the
disc carrying the magic lantern slides so that directly the disc begins to rotate the
peg strikes against the lever and turns on the gas. When the lever is thus raised

page_text: a projection upon it is pressed past a spring catch and so the lever is held. The
spring catch consists of a bar which is pivotted at one end and sliding a short way
to one side allows the projection on the gas cock lever to pass. The pivotted bar
has upon it the armature of an electro-magnet. When a current is passed through
this magnet the armature is attracted and thereby pulls the catch bar to one side
and releases the gas-cock lever which falls by its own weight or is pulled down by
a spring and thus turns down the gas leaving only a very small flame. The current
for turning down the gas is sent from a contact maker on the before mentioned
24 hour disc on the clock. In order to ensure time being given to allow the gas
cock lever to fall before the catch returns after the momentary passage to the
turning off current we retain it in its withdrawn position by means of a spring
catch which holds it back out of the way of the gas cock lever until the latter has
fallen nearly to the bottom of its travel when a hook upon it strikes upon the
spring catch and thus releases the pivotted bar and allows it to again get into
position to hold the gas cock lever when the gas is again turned on. This part of
the Invention is applicable in all cases in which cocks are required to be turned on
and off periodically.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Ernest Webster and Tom Mayor Williams in the Great Seal Patent
Office on the 23rd June 1882.
ERNEST WEBSTER of Loudoun Road and TOM MAYOR WILLIAMS of Corbyn
Street both in the County of Middlesex. "IMPROVEMENTS IN APPARATUS FOR
EXHIBITING MAGIC LANTERN PICTURES PARTS OF WHICH ARE APPLICABLE TO
OTHER PURPOSES."
This Invention has for its object improvements in apparatus for exhibiting
magic lantern pictures parts of which are applicable to other purposes.
The apparatus is especially designed for displaying advertisements and the like
in shop and other windows. For this purpose we arrange a number of magic
lantern slides around the circumference of a disc to which a step by step rotation
is given so that the slides are brought one by one in succession opposite to the
lantern and are thus cach exhibited in turn for any given period say half a
minute. The slides fit into grooves in the edges of recesses cut in the disc so that
any of the slides can easily be removed and others substituted. Or the slides
might be carried by a drum-with-a-similar-movement..
The disc is driven by a weight or spring or otherwise and its movement is
regulated by an escapement actuated by a clock.
In order that, our Invention may be most fully understood and readily carried
into effect we will proceed to describe the Drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a front elevation and Figure 2 is a side elevation of the lantern and
slide carrying disc. a is the disc. b. b. are the optical parts of the lantern and
c is the burner, chimney and subsidiary parts. aa are grooved wooden blocks
around the periphery of the disc, they are secured to the central part by the brass
straps a* a. a. a². are bolts by which the straps are attached; these bolts
project from the back of the disc. a. a. are the magic lantern slides which it is
desired automatically to exhibit in succession. These slides are passed into their
positions between the blocks a¹. and are then secured by the clips a. which when
the screws connecting them with the blocks are slackened can be turned to one
side. These clips are clearly seen in Figure 3 which represents a portion of the
disc to a larger scale. Figure 4 is a back elevation of the disc a with other parts,
the blocks a. and slides a³. are omitted from this Figure. Figure 5 is an elevation
and Figure 6 is a plan of a train of gear connecting the axis of the disc a with
a weight d so that the disc is always ready to rotate when permitted to do so.
e is an escapement lever pivotted at el. and operating with the pins a². to control
the movement of the disc.
The pins a². it will be observed are equal in number to the lantern slides a. and
at the time that the escapement lever is engaged with any one of these pins a
corresponding slide is in proper position in respect to the optical parts of the
apparatus to cast its image upon the magic lantern screen. f is an electro magnet
which when a current passes in its coils, attracts an armature fixed upon an arm c².
of the escapement lever. When the armature is attracted the disc is set free and
commences to turn. The currents passed through the magnet f are of short
duration and immediately the current ceases the escapement lever is brought back
by the spring e. to the adjustable stop e. thus the escapement lever after releasing

page_text: one of the pins a². is always ready to stop the disc again by the time tho next stop
pin a. comes round.
If the clock should stop whilst the battery current is passing in the magnet f,
the disc would be prevented revolving by the arm e³. of the escapement lever with
which one of the stop pins a³. would then come in contact, this is a safeguard
against injury to the apparatus. g is a locking pawl to prevent rebound of the disc
when the pins a strike the escapement lever.
The battery circuit is closed through the magnet f, by means of a clock, of which
parts are shewn in Figure 7. Ath are a pair of springs, shewn separately at
Figure 8 and i is a lever; the space between these springs and the end of the
lever is when the apparatus is at work the only opening in the circuit, the lever i
is pivotted at . when it is allowed to fall its end enters between the springs and
completes the circuit, le is an axis in the clock train which rotates once per minute,
it carries two similar double cams l. 1. and m. m. The cam as the axis revolves
raises and drops the lever i. once every half minute, the other cam m. operates
similarly upon a lever n. The cam m is set behind the cam l. so that it operates
immediately after it, the interval which represents the duration of the battery
current is exaggerated in the Drawing. n¹. is an arm of the lever n it carries a
projecting pin n. and when the lever n, falls this pin strikes upon the lever i. and
draws it up from between the springs h thus causing the current to cease. In
order that the apparatus may be entirely automatic (requiring nothing more than
winding once a week) it is necessary that the apparatus should be self starting in
the evening, and should stop of itself at the prearranged hour of the night; also
that the gas should be turned on and off at the proper times. Now the movement
of the apparatus deponds as already explained, on the passage of periodic currents
in the coils of the magnet f. The circuit of this magnet is through the insulated
spring o. to the sectors p. p. and the metallic movement of the clock. The sectors
are carried upon an axis q, of the clock work and this axis rotatos once in 24 hours.
The sector can be clamped upon the axis in any position so that this contact of
the spring o with them, or with one or other of them, may be continued during
any desired portion of the night. So long as there is contact between the spring
and sectors the disc a will continue to make its half minutely movements, but
when this contact ceases the disc will no longer turn. In order to cut off the gas
at the end of the evening the gas cock r is provided upon the pipe which supplies
the burner of the lantern. Upon the plug of the cock there is an arm r¹, and
this is connected by a chain with a lever 8, which carries the armature of an
electro magnet t. When the battery circuit is complete through the coils of this
electro magnet, the armature is attracted, the arm is drawn down and the gas
is turned off, excepting a small flame for relighting when it is again turned on.
Immediately the current ceases to pass through the coils of the magnet t. the
lever a, is again lifted by the spring 8', but the position of the gas cock is not
altered the circuit of the electro magnet t is always closed with the exception of
a break at the springs u. u. Now one of the sectors p is furnished with a small
tooth p', and this at the time for extinguishing the gas comes into contact with
one of the springs u. and bends it until it comes into contact with the other spring
and thereby for a short time closes the circuit. The gas will not again be turned
on until the apparatus is next started and then one of the pins a² will come against
the arm upon the plug of the gas cock. The plug will then be turned and the
gas again burning up, the exhibition upon the magic lantern screen will
recommence, and it will continue through the evening without requiring the
attention of an attendant.
The clock circuit closer or electric transmitter is applicable also for driving
secondary clocks and for other useful purposes.
Having thus described the nature of our said Invention and the manner of
performing the same we would have it understood that we claim :-
First. Our improved apparatus for automatically exhibiting magic lantern

page_text: pictures, consisting of a disc or drum carrying magic lantern slides which under the
control of a clock is permitted to rotate step by step and then brings up the slides
into position, to display the image of each in turn upon the magic lantern screen,
substantially as herein described.
Second. Our clock circuit closer or electric transmitter substantially as herein
described.
In witness whereof I the said Tom Mayor Williams have set my band and
seal this Twenty third day of June in the year of our Lord One thousand
eight hundred and eighty two.
TOM M. WILLIAMS. (L.S.)
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