Improvements in Transposing Apparatus applicable to Keyboard Musical Instruments.
Year: 1893

page_text: Date of Application, 12th Apr., 1893
Complete Specification Left, 24th June, 1893-Accepted, 29th July, 1893
PROVISIONAL SPECIFICATION.
Improvements in Transposing Apparatus applicable to Keyboard
Musical Instruments.
I, LOUIS ADOLPHE IVON, of 11, Rue Léon Cogniet, Paris, in the Republic of
France, Lieutenant Colonel, do hereby declare the nature of this invention to be as
follows:-
"This invention relates to the construction of a portable transposing keyboard.
capable of being applied to the keyboards of pianos or other keyboard musical
instruments and affording even a lighter touch than the piano itself.
The keyboards of pianos of 7 octaves.vary to the extent of 3 or 4 centimetres
in length. In order therefore to construct a portable transposer which can be
applied to any piano it is necessary to divide this difference over the whole length
of the transposing keyboard and to do this accurately I draw a plan or diagram
representing two keyboards of 7 octaves of the minimum and maximum lengths
one beneath the other care being taken to place the middle of the two keyboards,
that is to say, the middle of the re key of the 4th octave from the bass end of
the keyboard on the same vertical line.
Near the middle ret key the keys of the same name of the two keyboards will
nearly coincide but the said keys will coincide less and less the farther they are
from the middle re on both the right and left hand sides. The parts of the white
notes which are opposite one another; I mark beneath the two keyboards and then
mark the centre of the said parts which will be the points on which the keys of
the transposing keyboard will act by means of pins the diameter of which is less
than the width of any of the said opposite parts of the white keys so that a person
depressing any key of the transposing keyboard will also operate a key of the
piano keyboard, provided it is comprised between the said minimum and maximum
lengths.
On the plan I also mark at the ends of the said minimum and maximum
keyboards the cheeks or blocks usually situated next the end keys in pianos, then
the parts of each two cheeks opposite one another will represent the cheeks of the
transposing keyboard.
In order to enable the invention to be fully understood 1 will describe the same
by reference to the accompanying drawings in which:
Figure 1 is a diagram illustrating the size of part of the transposing mechanism
in relation to the black keys of the keyboard of the instrument.
Figure 2 is a diagram showing how movement is transmitted from the transposing
keyboard to the keyboard of the instrument.
Figure 3 is a sectional view shewing my transposing apparatus applied to the
keyboard of an instrument the line C indicating the rear end of the said keyboard
and D a plate for covering the mechanism.
Figure 4 is a view drawn to a smaller scale showing the transposing keyboard
with twelve registering openings i, hereinafter described.
Figures 5 and 6 are views of details hereinafter described.
For the black notes the operating pin will be of the width a, b, Figure 1,
comprised between the two notes of the same name (do for example) of the two
keyboards.
'
I will now describe by reference to Figure 2 how the keys of the transposing
keyboard a, o pivoting at: o' transmit movement to the keys of the piano
keyboard o, 6 pivoting at o.
As the two movements are in the same direction transmitting levers o", c are
required having a movement in a contrary direction around a centre o". The

page_text: extent of the downward movement of c. will be equal to that‍ of the key o, b,
10 millimetres for example.
:.
-
Supposing that the extent of the downward movement of a, is 11 and d is the
point where the key a, o', will bear upon the transmitting lever o", c in order that
there may be no separation in the system and calling-
the two following equations will result
distance from all toda
the two following equations will result
0" cod: 10 : f
a of o:11:f'
.
Supposing and f¹ to be the depth of downward movement of the points fand d
in order that there may be no separation it is necessary that should be equal to f1 10
but this would generally cause great friction.
To prevent this as much as possible and give a light touch the point of contact b
must be taken on a line drawn through the centres o and o and the second point of
contact d is on a line drawn through the centres, o", o¹ as shown in Figure 3.
Here
a o' = 212™/m
a g =
40 r
0¹¹ c = 83
and the above mentioned equations become
(83) f = 10 (x)
(212) f11 (172-x)
which allows of determining fand 2.
The point of contact of the white key of the transposing keyboard with the
ordinary white key is thus regulated.
1
20
By using the same centre of for the white and black keys and by putting on the
same vertical the centres o¹ and ol of the transmitting levers for the white and 2
black keys I obtain the four systems of two equations for all cases of the move-
ment which are given below.

page_text: The transposing keyboard is about 1 15 from end to end or about 1 174 for
the 85 keys which is about the length of a medium sized keyboard in order that
the transmitting levers of the superposed keys may be in vertical planes.
. Should it not be desired to bear on the two end keys of each side the support.
may be taken on the cheeks.
The two bars and k are connected at the right and left hand by two side pieces
sufficiently thick to extend over the two cheeks of the plan and which should have
two screws at each side to adjust the transposing keyboard upon these cheeks. A
cipher is registered which is marked on the screws when the transposing keyboard
is adjusted upon the cheeks of the plan the hypothesis being that the height of the
said cheeks is the same as the top of the white keys A of the keyboard of the
piano. Then if the cheek upon which the transposer should actually be placed.
is 4, 6, 10 etc. millimetres higher than the white keys it is only necessary to raise
the screws to make the cipher arrive at 4, 6, 10% &c. above the mark in order to
adjust the transposer.
This will be understood by reference to Figures 5 and 6 of the drawings which
are front elevations of part of the piano keyboard and one of the cheeks of the
same with parts of the transposer applied thereto.
A, A, are the white keys and E is the left hand cheek of the piano. The two
cheeks support the bars and h (Figure 3) of the transposer, the height of which
with relation to the keys of the piano can be varied and adjusted by means of the
screws F, F' (Figure 5) according to the thickness of the cheeks.
I provide at each side of the lower and fixed part of the transposer a bracket G
at a height sufficient to allow the largest cheek to pass beneath and which carries
the two screws F, F' the supporting point of which upon the cheek can be easily
determined in the following manner. Referring to the two maximum and minimum
keyboards hereinbefore mentioned the lengths of which are 1190 and 1159 milli-
metres, respectively drawn one above the other so that their middles coincide, the
larger extends beyond the smaller at each side to the extent of 15 millimetres so
that assuming the smallest cheek to be met with is 20 millimetres or more in width
there will still remain a common part of the cheek measuring 20-15=4+ milli-
metres the middle of which will serve as the bearing point for all intermediate
keyboards.
The screws are so regulated as to have their bottoms at the height of the white
keys for the front two and at the height of the top of the sharps for the back two
and as the cheeks would interfere with adjusting the bottom of the screw in this
position the top of the head of the screw is registered on a small vertical scale G²
graduated in millimetres and placed at one side over the bracket G and zero is
marked at this point.
If then a cheek should be met with having for example seven millimetres in
height above the white keys it is only necessary to place the top of the head of the
screw level with the figure 7 on the scale and then to place the apparatus on the
piano.
With regard to this height of seven millimetres this can be ascertained in each
case by means of a small wooden plate or board H, Figure 6 which rests upon the
cheek E; a small screw I working in this board at each side of the piano is lowered
until it bears against the key. The extent of movement of the lower part of this
screw will be the distance sought.
Should the cheeks be less than twenty millimetres in width the support can be
effected above in the same manner by a screw F¹ placed ten millimetres nearer the
centre than F which would replace the screw F.
At each end of the transposer is a pin or eye J (Figure 5) which embraces one
end of a clamp K which passing under the piano, can by a screw L placed beneath,
secure the transposer to the piano. The transposer also carried at its middle part a
small board resting on the front of the piano so as to prevent any deflection of the
transposer notwithstanding its length..
At the distances a, a, y, y', Figure 3 from the vertical line drawn through the
".

page_text: centres o, o are cylindrical wooden pins of about 7 mm in diameter which are
screwed into the upper keys A¹ their screw-threads allowing of their being adjusted;
each key carries one long pin ; and one short pin j the said pins of the white keys A'
being situated at' the distances" x, y and those of the black keys B' at the
distances ¹, y¹. The transmitting levers placed at the angle oli o' are about
17 in width and the levers u placed at the angle o¹¹ o' are about 12 /m 5 in
width. The levers t have each an opening p, g of about 12./m in width which
allows the long pin of each key A' or B₁ to pass through so as to be inoperative
when the short pin of the same key acts.
.
'
The keys A'B' of the transposer fall automatically by their own weight and are
provided at suitable distances from their points of oscillation with lead let into the
material of the keys whereby they are caused to bear.lightly upon the keys A B of
the piano and they are assisted in rising by springs v, w placed under the levers t, u."
A small catch pivoting at s serves to lock the levers when requiring to prevent the
instrument from being played. To transpose a piece of music the plate / is lifted
thereby raising the keys A' B' and the two sides which have the same centre of
rotation of upon the plate which is adapted to slide along the bar k. The plate r
is moved either to the right or left hand as the case may be to the required
extent that is to say according to the number of semi-tones it is wished to transpose
up to and the plate and keys are then lowered into the position shewn in
Figure 3.
go.
· To prevent accidents when shifting the transposing keyboard for example to
prevent the pins j¹ from laterally striking the levers t, a pin n, m is fixed to the
under side of the plate and lateral movement can only take place when the said
pin is disengaged from the hole in the bar h, there being twelve of such holes as
shewn at i in Figure 4. These holes correspond with the twelve semi-tone trans-
positions and when the pin n, m is disengaged from the bar h the vertical pins ;' are
clear of the transmitting levers t.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Transposing Apparatus applicable to Keyboard,
Musical Instruments.
I, LOUIS ADOLPHE IVON, of 11, Rue Léon Cogniet, Paris, in the Republic of
France, Lieutenant Colonel, do hereby declare the nature of this invention and in
what manner the same is to be performed to be particularly described and ascer-
tained in and by the following statement :-
"
This invention relates to the construction of a portable transposing keyboard
capable of being applied to the keyboards of pianos or other keyboard musical
instruments and affording even a lighter touch than the piano itself.
The keyboards of pianos of 7 octaves vary to the extent of 3 or 4 centimetres in
length. In order therefore to construct a portable transposer which can be applied
to any piano it is necessary to divide this difference over the whole length of the
transposing keyboard and to do this accurately I draw a plan or diagram
representing two keyboards of 7 octaves of the minimum and maximum lengths one
beneath the other care being taken to place the middle of the two keyboards, that
is to say, the middle of the rekey of the 4th octave from the bass end of the
keyboard on the same vertical line.
Near the middle re key the keys of the same name of the two keyboards will
nearly coincide but the said keys will coincide less and less the farther they are
from the middle re on both the right and left hand sides. The parts of the white
notes which are opposite one another, I mark beneath the two keyboards and then
."
1

page_text: mark the centre of the said parts which will be the points on which the keys of the
transposing keyboard will act by means of pins the diameter of which is less than
the width of any of the said opposite parts of the white keys so that a person
depressing any key of the transposing keyboard will also operate a key of the
piano keyboard, provided it is comprised between the said minimum and maximum
lengths.
On the plan I also mark at the ends of the said minimum and maximum keyboards
the cheeks or blocks usually situated next the end keys in pianos, then the parts of
each two cheeks opposite one another will represent the cheeks of the transposing
keyboard.
In order to enable the invention to be fully understood I will describe the same
by reference to the drawings accompanying my Provisional Specification, in which :-
Figure 1-is a diagram illustrating the size of part of the transposing mechanism
in relation to the black keys of the keyboard of the instrument.
Figure 2 is a diagram showing how movement is transmitted from the transposing
keyboard to the keyboard of the instrument.
:
'
Figure 3 is a sectional view shewing my transposing apparatus applied to the
keyboard of an instrument the line C indicating the rear end of the said keyboard
and D a plate for covering the mechanism.
Figure 4.is.a view drawn to a smaller scale showing the transposing keyboard
with twelve registering openings i, hereinafter described.
Figures 5 and 6 are views of details hereinafter described.
For the black notes the operating pin will be of the width a¹, b¹, Figure 1,
comprised between the two notes of the same name (do for example) of the two
keyboards.
1 will now describe by reference to Figure 2 how the keys of the transposing
keyboard a, o' pivoting at o' transmit movement to the keys of the piano keyboard o, b
pivoting at o.
}
As the two movements are in the same direction transmitting levers o", c are
required having a movement in a contrary direction around a centre o". The
extent of the downward movement of c will be equal to that of the key o, b,
10 millimetres for example.
+
Supposing that the extent of the downward movement of a, is 11 mm and d is the
point where the key a, o', will bear upon the transmitting lever-o", c in order that
there may be no separation in the system and calling the distance from o¹¹ to d,
the two following equations will result
* !
•

page_text: By using the same centre o' for the white and black keys and by putting on the
same vertical the centres oll and o¹ of the transmitting levers for the white and
black keys I obtain the four systems of two equations for all cases of the movement
which are given below..
The transposing keyboard is about 1" 15 from end to end or about 1 174 for the
85 keys which is about the length of a medium sized keyboard in order that the
transmitting levers of the superposed keys may be in vertical planes.
Should it not be desired to bear on the two end keys of each side the support
may be taken on the cheeks.
The two bars h and k are connected at the right and left hand by two side pieces
sufficiently thick to extend over the two cheeks of the plan and which should have
two screws at each side to adjust the transposing keyboard upon these cheeks. A
cipher is registered which is marked on the screws when the transposing keyboard
is adjusted upon the cheeks of the plan the hypothesis being that the height of the
said cheeks is the same as the top of the white keys A of the keyboard of the piano.
Then if the cheek upon which the transposer should actually be placed is 4, 6, 10 etc.
millimetres higher than the white keys it is only necessary to raise the screws to
make the cipher arrive at 4, 6, 10' &c. above the mark in order to adjust the
transposer.
m
This will be understood by reference to Figures 5 and 6 of the drawings which
are front elevations of part of the piano keyboard and one of the cheeks of the
same with parts of the transposer applied thereto.
A, A, are the white keys and E is the left hand cheek of the piano. The two
cheeks support the bars k and h (Figure 3) of the transposer, the height of which
with relation to the keys of the piano can be varied and adjusted by means of the
screws F, F (Figure 5) according to the thickness of the cheeks.
I provide at each side of the lower and fixed part of the transposer a bracket G

page_text: at a height sufficient to allow the largest cheek to. pass beneath and which carries
the two screws F, F' the supporting point of which upon the cheek can be easily
determined in the following manner. Referring to the two maximum and
minimum keyboards hereinbefore mentioned the lengths of which are 1190 and
1159 millimetres, respectively drawn one above the other so that their middles
coincide, the larger extends beyond the smaller at each side to the extent of
15 millimetres so that assuming the smallest cheek to be met with is
20 millimetres or more in width there will still remain a common part of the cheek
measuring 2015 = 4 millimetres the middle of which will serve as the bearing
point for all intermediate keyboards.
The screws are so regulated as to have their bottoms at the height of the
white keys for the front two and at the height of the top of the sharps for the
back two and as the cheeks would interfere with adjusting the bottom of the screw
in this position the top of the head of the screw is registered on a small vertical
scale G¹ graduated in millimetres and placed at one,side over the bracket G and
-zero is marked at this point.
If then a cheek should be met with having for example seven millimetres in
height above the white keys it is only necessary to place the top of the head
of the screw level with the figure 7 on the scale and then to place the apparatus
on the piano.
With regard to this height of seven millimetres this can be ascertained in each
case by means of a small wooden plate or board H Figure 6, which rests upon the
cheek E; a small screw I working in this board at each side of the piano is
lowered until it bears against the key. The extent of movement of the lower
part of this screw will be the distance sought.
Should the cheeks be less than twenty millimetres in width the support can be
effected above in the same manner by a screw F' placed ten millimetres nearer the
centre than F which would replace the screw F¹.
At each end of the transposer is a pin or eye J (Figure 5) which embraces one
end of a clamp K which passing under the piano, can by a screw L placed beneath;
secure the transposer to the piano. The transposer also carried at its middle part
a small board resting on the front of the piano so as to prevent any deflection of.
the transposer notwithstanding its length.
At the distances a, x, y, y, Figure 3, from the vertical line drawn through the.
centres o, o are cylindrical wooden pins j, of about 7 in diameter which
are screwed into the upper keys A¹ their screw threads allowing of their being
adjusted; each key carries one long pin j¹ and one short pin; the said pins of the
white keys A' being situated at the distances x, y and those of the black keys B¹
at the distances, y'. The transmitting leverst placed at the angle oll,
are about 17 mm in width and the levers u placed at the angle o", o' are
about 125 in width. The levers t have each an opening p, q of about 12
width which allows the long pin of each key A¹ or B' to pass through so as to be
inoperative when the short pin of the same key acts.
in
.
The keys A, B, of the transposer fall. automatically by their own weight and
are provided at suitable distances from their points of oscillation with lead let into
the material of the keys whereby they are caused to bear lightly upon the
keys A B of the piano and they are assisted in rising by springs v, w placed under
the levers t, u. A small catch pivoting at serves to lock the levers when
requiring to prevent the instrument from being played: To transpose a piece of
music the plate is lifted thereby raising the keys A', B' and the two sides which
have the same centre of rotation o' upon the plate which is adapted to slide
along the bar k. The plate r is moved either to the right or left hand as the case
may be to the required extent that is to say, according to the number of semi-tones
it is wished to transpose up to and the plate / and keys are then lowered into the
position shewn in Figure 3.
To prevent accidents when shifting the transposing keyboard for example to
prevent the pins from laterally striking the levers t, a pin n, m is fixed to the

page_text: under side of the plate and lateral movement can only take place when the, said
pin is disengaged from the hole in the bar',,there being twelve of such holes as
shewn at in Figure 4. These holes correspond with the twelve semi-tone
transpositions and when the pin n, m is disengaged from the bar h the vertical
pins are clear of the transmitting levers t..
•
3: 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. A. transposing apparatus applicable to pianoforte keyboard of various lengths,
constructed according to the plan or diagram herein referred to by which the
difference between two keyboards of 7 octaves of minimum and maximum
lengths is divided over the whole length of the transposing keyboard, substantially
as hereinbefore described.
2. Placing the superposed keyboard on the two end white and black keys so as
to have a position almost constant to facilitate the theoretical adjustment of the
transposing keyboard, substantially as herein before.described.
3. The practical adjustment on checks or blocks of variable height taking for a
basis cheeks of the same height as the white keys of the piano, substantially as
hereinbefore described.
1
4. The clamps for fixing the transposing device to the piano, substantially as
herein before described.
5. The middle support on the front of the piano for preventing the deflection
of the transposing mechanism notwithstanding its length, substantially as herein-
before described. .
:
6. The combination with the keys of vertical wooden transmitting pins
provided with screw threads to allow of their being adjusted, substantially as
described.
7. Locating the points of contact on lines connecting the centres of rotation
in order that all the circles described may be tangents whereby friction is reduced
and a light touch is afforded, substantially as hereinbefore described.
8. Keys which fall automatically by their own weight. the said keys being
provided at suitable distances from their points of oscillation with lead let into the
material of the keys, substantially as described.
4'19
•
9., The system of supporting on cheeks arranged according to the plan or
diagram herein referred to whereby a keyboard of medium length is produced
provided with a narrow cheek and of a height level for, example with the white
Keys of the piano and thus serving to regulate the supporting screws in all cases,
substantially as hereinbefore described.
"
10. The combination of parts forming the improved, transposing mechanism
for keyboard musical instruments hereinbefore described and illustrated in the
accompanying drawing.
i
נים
1909