Year: 1886

page_text: I ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex
Engineer, do hereby declare the nature of this invention (a communication from
Carl Robert Viehofer, Teacher of Insterburg) 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 improvements in teaching apparatus and has for its
object to facilitate the teaching of children (especially in reading and writing) to
strengthen their optic powers and memory and to bring about a conformity in the
system of teaching.
Teaching by ocular demonstration, which, as is well known, shews the best
results, forms the basis of the system which has given rise to the invention of this
apparatus.
The attention of the children is called, by a clicking noise, to a representation of
subjects, letters in printed or written form, or figures, appearing on a relatively large
surface, which latter is to strengthen the eyes of the children, preferably of a leaf
green colour, and the memory of the children is called upon by the teacher
suddenly covering the representation after a suitable period of time.
The representation is for this purpose pasted on cardboard which is fitted in the
folds or laps of a piece of tin (Figure 2b), which latter is fastened in an easy dis-
connectable manner to one of the equally large sides of a polygonal drum A
journalled in the frame B, which frame also carries the screen S preferably green,
through a slot D in which the representation can be seen by a certain turning of
the drum.
On the screen S and above the slot D is hinged horizontally a flap K connected
with the drum A by a suitable mechanism in such a manner that the flap covers
the slit D while the drum is being turned and does not uncover it until another
representation is standing directly behind the slit and the operator let go the
apparatus.

page_text: The drum A. on which the tins a carrying the representation are fastened, has
preferably a regular polygonal section (say 16 sides) the flats of which are of the
same size as the tins a. These latter are preferably fastened to the flats of the drum
by lugs and buttons fitting into slits provided in the tins.
The shaft c of the drum is journalled in the frame B fastened on one side to the
standard E while carrying on the other side on the horizontal arms C C the
screen S by the hooks h and h¹ (Figure 1b and 4) The screen S consists of a frame
braced by vertical laths L L and covered with green fabric with exception of the
slit D which is left free. It can be folded together by the hinges t t and carries
above the slit D the flap K.
On the axis of the hinge of the flap K is fastened a small roller s while on the
inside of the screen at the same height is provided a small guide roller, r.
A cord or thin chain m is fastened to the rollers s (Figures 2ª, 3. 3a) while its
other end after passing over the guide roller r is fastened to one arm of the two-
armed lever i pivotted to one of the arms C C while its other arm rests on the
pin p of the combined lever p q (Figures 3, 3a) so that a lifting of the lever p q
will draw the cord or chain m and thereby lift the flap K and uncover the slot D,
while a lowering of the pin 23 will allow the flap K to fall by its own weight and
cover the slot D.
The combined lever p q. (Figs. 3, 3ª, 5, 5º), the pin p³ of which performs the
above described functions; is pivotted to an horizontal bracket F on one of the
arms C, and passes through a slot O of the latter and engages by the thumb p
with a ratchet mechanism ef R (Figs. 4, 4, 3 and 3ª) by which the turning of the
drum A is regulated.
The combined lever p q consists of the two two arined levers p and q pivotted to
the bracket F in p¹ and q¹ connected by the pin p², fastened to the lever p and
moving in a slot of lever q, and by the spring w (Figure 5) in such a manner that
when the button q² of the lever is pressed down the thumb p' and the pin p³ will
also be pressed down, while the spring w will force the two levers apart and thereby
lift the thumb p' and pin p³ when the button q² is released.
The ratchet mechanism e f R with which engages the combined lever p q by the
thumb p (Figure 4 and 4") of a two armed lever f pivoted at f¹ in the arm c and
in the eye g of which lever works the thumb p4, while it engages with a pawl e by
the arm e, which pawl e is operated by a spring vin such a manner that the pawle
in its downstroke is pressed against a bolt R operated by a spring v¹ which bolt R
by its nose n arrests one of the pins d a number of which equal to the number of
sides of the drum are arranged in equal distances from each other and concentrically
around the axis of the drum on one of the sides thereof.
This mechanism is constructed in such a manner that when the lever f is in
horizontal position two of the pins d are always arrested by the pawl e and a
lateral projection f' of the lever f while a third pin d is held by the nose n of the
bolt R. In its downstroke the pawl e will engage with the third pin d the bolt R
being pressed back, and will then lift this pin until the lever f is again in a
horizontal position in which it is stopped by the pin u.
is
The apparatus will operate as follows:-When the button q² of the lever
pressed down by the operator, the spring w will be bent and the thumb p and
pin 2 of the lever p will be pressed down and the lever f thereby raised from
its inclined position into a horizontal one (Figures 3 and 3º), while the drum A is
turned for the distance of one of its polygonal sides by the pawl e and the
lever at the same time released from the pressure of the pin p³ so that the flap K
falls by its own weight and covers the slit D of the screen S.
When the operator releases the button q² the spring w will force the two
levers P and q apart and so cause a lifting of the thumb pt and the pin p³ and in
consequence a lifting of the flap K and an uncovering of the slit D in the screen S
while the pawl e is lowered until it engages the pin d held up to this by the
bolt R.

page_text: Having now particularly described and ascertained the nature of this said
invention and in what manner the same is to be performed as communicated to
me by my foreign correspondent I declare that what I claim is :-
1. A teaching apparatus such as specified consisting essentially of a polygonal
drum A on the sides of which are fastened representations of subjects letters or
figures which can be unfastened from the drum and exchanged for fresh ones and
are regarded by the scholars through a slit D in a screen S fastened to the standard E
in which the drum is journalled, said screen being provided over the slit D with a
movable flap K which is connected with the revolving mechanism of the drum in
such a manner that it covers the slit when the drum is being turned and uncovers
the slit when the mechanism is released substantially as specified.
2. In a teaching apparatus such as described a ratchet mechanism by which the
drum A is turned by the pins d d a number of which equal to the number of the
flats of the drum are fitted into one of the ends thereof at equal distances from
each other and from the centre of the drum in combination with the lever i
operating the flap K by a cord or chain m the said ratchet mechanism con-
sisting of a pair of levers p and q connected with each other by the pin p³ and
the spring wand which levers operate the lever i by the pin p³ and the lever fe
by the thumb p* respectively while the arms e of the lever f c operated by the
spring v in its downstroke presses the bolt R back and engages with one of the pins d
previously held by R and lifts the pin with it in its upstroke substantially as and
for the purpose specified.