IMPROVEMENTS IN AUTOMATIC Musical InstruMENTS
Year: 1874

page_text: LETTERS PATENT to Daniel Imhof, of No. 547, Oxford Street, in
the County of Middlesex, for the Invention of "IMPROVEMENTS IN
AUTOMATIC Musical InstruMENTS.”
Scaled the 18th September 1874, and dated the 27th July 1874.
PROVISIONAL SPECIFICATION left by the said Daniel Imhof at the
Office of the Commissioners of Patents, with his Petition, on the
27th July 1874.
I, DANIEL IMHOF, of No. 547, Oxford Street, in the County of
Middlesex, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN AUTOMATIC MUSICAL INSTRUMENTS," to be as follows:―
This Invention relates to improvements in that class of automatic
musical instruments wherein projections or hollows on a revolving barrel
or other travelling surface are so arranged as to cause hammers to strike
strings, bells, springs, or other sounding bodies, thereby producing
different musical notes corresponding in order to the succession of the
projections or hollows on the travelling surface. In such instruments

page_text: it is usual to load the hammers or to provide them with springs so
as to impel them against the sounding bodies, and to arrange the moving
projections so as to act on the noses or key points of the hammer levers,
withdrawing the hammers from the sounding bodies in opposition to their
weights or springs until the projections having passed the noses of the i
levers the hammers are discharged, effecting their strokes. According to
this arrangement considerable strain is thrown upon the travelling pro-
jections, and there are difficulties in obtaining rapid action and in
damping or stopping the vibration of the successive notes.
According to my improvements, which I will describe, the strain upon :
the travelling projections is very much reduced, the withdrawal of the
hammers preparatory to their stroke being effected by mechanism which
is brought into action by the travelling projections or hollows, and not
being directly effected by these projections or hollows themselves. This
diminution of strain on the moving parts renders it possible to reduce the
weight, strength, and size of the barrels and their pegs, and to substitute
for such pegged barrels weaker material, such as paper or cardboard,
perforated with holes and caused to travel by means of rollers or other-
wise. Moreover by the arrangement which I will describe I am enabled
to work dampers, so as to stop the vibration of the sounding bodics at
longer or shorter intervals after they have begun to sound. For this
purpose I provide near or under the row of hammer levers a cylinder
made to revolvo quickly by gearing connecting it with the revolving
barrel or other travelling surface, and fluted on its periphery with
fine teeth extending its entire length. Under or beside each hammer
lever I provide a short rack, having teeth corresponding to those of the
cylinder. Each of these racks is kept by a light spring or counter-
balanco at a little distance from the surface of the cylinder, and has a
lever arm with a key point or nose resting on the revolving barrel.
When a peg of the barrel passes this key point or nose it moves the lever
arm, so as to cause the rack to bear against the cylinder and to gear
therewith, and the cylinder by its rapid revolution thereupon moves the
rack suddenly forward. A projection on the rack is thus brought
against an arm of the hammer lever, which it moves in opposition to its
weight or spring, and when it has moved it a certain distance, escapes,
discharging the hammer so as to strike the note.
When instead of news hollows in a revolving barrel or holes in travelling.

page_text: arranged so that usually it rests on the travelling surface, but when it
drops into one of the hollows or holes it brings the rack into contact
with the toothed cylinder, whereby the hammer is worked as already
described. The mack is also connected to a damper lever, so that
when it is moved by the teeth of the cylinder it raises the damper off
the sounding body before the hammer is discharged, leaving it free to
vibrato under the stroke of the hammer. The peg or hollow on the
revolving barrel or the hole in the travelling surface being made of
length proportioned to the desired duration of the note, the damper is
withheld from the sounding body so long as the peg, hollow, or hole is
passing the key point of the rack arm, but when the peg, hollow, or
hole has passed the said key point, the rack being thereby raised off the
surface of the toothed cylinder is caused by a light spring or counter-
weight to make a back stroke, letting the damper fall on the sounding
body, and taking a position where it is ready to be again acted on by a
succeeding peg, hollow, or holo on the travelling surface.
Instead of a rack as above described, which is made to advance by the
revolving cylinder when it is engaged with it, and which makes a back
stroke when it is disengaged, a wheel may be used toothed in parts of its
periphery, and without teeth in other parts. When the part having no
teeth faces the revolving cylinder this wheel remains at rest, but when
by the action of a projection, hollow, or hole in the travelling surface
this wheel is turned partly round till a toothed part of its periphery is
brought to face the revolving cylinder, the teeth of the wheel being
thereby engaged with those of the cylinder the wheel is caused to turn
until a part without teeth presents itself, when it becomes again dis-
engaged. Pegs or projections on the side of the wheel corresponding to
the toothed parts of its periphery are thus made to act on the hammers
and dampers every time that the wheel makes a partial revolution.
Instead of forming teeth on the revolving cylinder and also on the
racks or wheels above described, the cylinder may be made with an
impressible surface, such as leather, in which the tecth of the racks or
wheels can imbed themselves; or the cylinder being toothed, the racks
or wheels may be made with such impressible surface. When the
cylinder is thus made with an impressible surface the rack or wheel may
may be made with only one tooth, so that it becomes in reality a lever
with a pointed end, which end is usually clear from the surface of the
cylinder except when a peg on the travelling surfaco or a hole therein,

page_text: acting on the arm on which it is mounted allows the point of the lover
to bear against the revolving cylinder, into the surface of which it
impresses itself. By the revolution of the cylinder the pointed lever is
caused to rock on its fulcrum, and so to raise the damper and to effect
the withdrawal and discharge of the hammer to which it is connected.
When at the termination of the peg on the travelling surface or of the
hole in it the pointed lever is again raised from the surface of the
cylinder, it returns to its normal position, its connection to the hammer
being effected by a pawl, which escapes when the lever makes its back
stroke.
It may be readily understood that apparatus such as described above.
may be applied to pianofortes or other percussive musical instruments
for working the hammers and dampers thereof without interfering with
the existing action of the finger keys.
SPECIFICATION in pursuance of the conditions of the Letters Patent, 1
filed by the said Daniel Imhof in the Great Seal Patent Office on
the 18th January 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, DANIEL
IMHOF, of No. 547, Oxford Street, in the County of Middlesex, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent bearing date the Twenty-seventh day of July, in the year
of our Lord One thousand eight hundred and seventy-four, in the thirty-
eighth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Daniel Imhof, Her special licensc
that I, tho said Daniel Imhof, my exccutors, administrators, and
assigns, or such others as I, the said Daniel Imhof, my executors,
administrators, and assigns, should at any time agree with, and no
others, from time to time and at all times thereafter during the
term therein expressed, should and lawfully might make, use, exercise,
and vend, within the United Kingdom of Great Britain and Ircland,
the Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS
IN AUTOMATIC MUSICAL INSTRUMENTS," upon the condition (amongst others)
that I, the said Daniel Imhof, my exccutors or administrators, by

page_text: an instrument in writing under my, or their, or one of their hands
and seals, should. particularly describe and ascertain the nature of
the said Invention, and in what manner the same was to be performed,
and cause the same to be filed in the Great Seal Patent Office within
six calendar months next and immediately after the date of the said
Letters Patent.
NOW KNOW YE, that I, the said Daniel Imhof, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement thereof, reference being had to the accompanying
Sheet of Drawings, and to the figures and letters marked thereon, that
is to say :-
This Invention relates to improvements in that class of automatic
musical instruments wherein projections or hollows on a revolving barrel
or other travelling surface are so arranged as to cause hammers to strike
strings, bells, springs, or other sounding bodies, thereby producing
different musical notes, corresponding in order to the succession of the
projections or hollows on the travelling surface. In such instruments
it is usual to load the hammers or to provide them with springs so as to
impel them against the sounding bodies, and to arrange the moving
projections so as to act on the noses or key points of the hammer levers
withdrawing the hammers from the sounding bodies in opposition to
their weights or springs, until the projections having passed the noses of
the levers the hammers aro discharged, effecting their strokes. According
to this arrangement considerable strain is thrown upon the travelling
projections, and there are difficulties in obtaining rapid action and in
damping or stopping the vibration of the successive notes.
According to my improvements, which I will describe, the strain
upon the travelling projections is very much reduced, the withdrawal of
the hammers preparatory to their stroke being effected by mechanism
which is brought into action by the travelling projections or hollows,
and not being directly effected by these projections or hollows themselves.
This diminution of strain on the moving parts renders it possible to
reduce the weight, strength, and size of the barrels and their pegs, and
to substitute for such pegged barrels weaker material, such as paper or
cardboard, perforated with holes and caused to travel by means of rollers,
or otherwise. Morcover by the arrangement which I will describe I am

page_text: enabled to work dampers so as to stop the vibration of the sounding
bodies at longer or shorter intervals after they have begun to sound.
For this purpose I provide near or under the row of hammer levers a
cylinder made to revolve quickly by gearing connecting it with the
revolving barrel or other travelling surface, and fluted on its periphery,
with fino tecth extending its entire length. Undor or besido cach
hammer lever I provide a short rack, having teeth corresponding to
'those of the cylinder. Each of these racks is kept by a light spring or
counterbalance at a little distance from the surface of the cylinder, and
has a lever arm with a key point or nose resting on the revolving barrel.
When a peg of the barrel passes this key point or nose it moves the lever
arm so as to cause the rack to bear against the cylinder and to gear
therewith, and the cylinder by its rapid revolution thereupon moves the
rack suddenly forward. A projection on the rack is thus brought
against an arm of the hammer lover which it moves in opposition to its
weight or spring, and when it has moved it a certain distance, escapes,
discharging the hammer so as to strike the note.
:
When instead of pegs hollows in a revolving barrel, or holes in
travelling paper, cardboard, or other surface are used, the lever arm of
the rack is arranged so that usually it rests on the travelling surface,
but when it drops into one of the hollows or holes it brings the rack into
contact with the toothed cylinder, whereby the hammer is worked, as
already described. The rack is also connected to a damper lever, so that
when it is moved by the teeth of the cylinder it raises the damper off the
sounding body before the hammer is discharged, leaving it free to
vibrate under the stroke of the hammer. The peg or hollow on the
revolving barrel or the hole in the travelling surface being mado of
length proportioned to the desired duration of the note the damper is
withheld from the sounding body so long as the peg, hollow, or hole is
passing the key point of the rack arm, but when the peg, hollow, or holo
has passed the said key point, the rack being thereby raised off the surface
of the toothed cylinder is caused by a light spring or counterweight to
mako a back stroke, letting the damper fall on the sounding body and
taking a position where it is ready to be again acted on by a succeeding
peg, hollow, or hole on the travelling surface.
Instead of a rack, as above described, which is made to advance by
the revolving cylinder when it is engaged with it, and which makes a
back stroke when it is disengaged, a wheel may be used, toothed in parts

page_text: of its periphery, and without teeth in other parts. When the part having
no teeth faces the revolving cylinder this wheel remains at rest, but
when by the action of a projection, hollow, or hole in the travelling
surface this wheel is turned partly round till a toothed part of its
periphery is brought to face the revolving cylinder, the teeth of the
wheel being thereby engaged with those of the cylinder, the wheel is
caused to turn until a part without teeth presents itself, when it becomes
again disengaged. Pegs or projections on the side of the wheel corrc-
sponding to the toothed parts of its periphery are thus made to act on
the hammers and dampers every time that the wheel makes a partial
revolution.
Instead of forming teeth on the revolving cylinder and also on the
racks or wheels above described, the cylinder may be made with an
impressible surface, such as leather, in which the teeth of the racks or
wheels can imbed themselves; or the cylinder being toothed the racks
or wheels may be made with such impressible surface. When the
cylinder is thus made with an impressible surface, the rack or wheel
may be made with only one tooth, so that it becomes in reality a lever
with a pointed end, which end is usually clear from the surface of the
cylinder, except when a peg on the travelling surface or a hole therein
acting on the arm on which it is mounted allows the point of the lever
to bear against the revolving cylinder, into the surface of which it
impresses itself. By the revolution of the cylinder the pointed lever is
caused to rock on its fulcrum, and so to raise the damper and to effect
the withdrawal and discharge of the hammer to which it is connected.
When at the termination of the peg on the travelling surface or of the
hole in it the pointed lever is again raised from the surface of the
cylinder it returns to its normal position, its connection to the hammer
being effected by a pawl which escapes when the lever makes its back
stroke.
It may be readily understood that apparatus such as described above
may be applied to pianofortes or other percussive musical instruments
for working the hammers and dampers thereof, without interfering with
the existing action of the finger keys.

page_text: of a barrel of ordinary construction, with pogs of lengths suited to the
required duration of the notes; S is one of the strings with its damper D
and hammer H. Under the knuckle of the hammer I mount a vertically
sliding bar A with escape action E of any known construction. To the
lower end of the bar A I connect by a wire W the end of a bent lever L, 5
the other end of which forms a key point acted on by the pegs on the
barrel B. A cylinder C is made to revolve rapidly in the direction of
the arrow.
The surface of this cylinder may be fluted or clothed, as
shewn, with leather or other suitable impressible material. A portion
of a rack or, as shown in the Figure, a single pin a fixed on the bar A is 1
presented towards the surface of the cylinder O, but clear of it. A
wire V extends upwards from the lever L to the damper D. When one
of the pegs on the barrel B (as it revolves in the direction of the arrow)
comes under the koy point of L it raises it, and thereby raises tho
damper D; at the same time by means of the wire W the lower end 1
of A is pulled towards the cylinder C, and the pin a being thereby
pressed against the impressible surface of C is moved suddenly upwards,
lifting tho bar A and escape action E, and causing the hammer H to
strike the string S. As long as the key point of L rests on a peg the
damper is kept up, and the noto that had been struck is sustained, but 2
when the key point of L drops behind a peg the damper comes against
the string, at the same time the pin a is pushed away from C, and the
bar A and escape action E drop ready to be acted on again.
Instead of employing projecting pegs on the barrel B the action may
bo effected by means of hollows therein, as shewn in Fig. 2, in which 2
the same letters are used to indicate parts corresponding with those
referred to in Fig. 1. In this case the barrel B is made with hollows in
it corresponding in their lengths to the required duration of the notes.
When the key point of the lever L drops into one of these hollows tho
damper is raised and the note is struck, as already described.
In order to overcome the weight of the damper and cause the key
point of L to drop, a spring T is conveniently applied at the back of tho
bar A.
3
Fig. 3 represents an arrangement according to which the hammer
instead of being worked by an escape action is drawn back against a 3
spring Y, and when let go is caused by the spring to strike. In this
case the cylinder C is made fluted with teeth along its surface, and is

page_text: caused to revolve in the direction of the arrow.
Above it is mounted
for each string a star wheel X or wheel with several teeth suited to gear
with those of C, but without the intermediate teeth. The lever L when
its key point is raised by a peg on the barrel B raises the damper D,
and at the same time by means of a spring pawl P acting on one of the
teeth of the wheel X moves that wheel partly round, so that another
of its teeth & engages with the teeth on C, whereby the wheel X is
farther turned, and another of its teeth is thereby mado to act on h,
the end of the hammer lever pushing it back in opposition to the
spring Y, and drawing the hammer H away from the string S. As soon
as the tooth escapes the spring Y causes the hammer head to
advance, striking the string. A buffer stops the hammer lever, which
above is made sufficiently elastic to allow the hammer head to be
carried forward by its momentum to strike. The one tooth having
been carried round by the teeth of O to the position of escapes, and
the wheel X remains at rest, until by means of another peg on the
barrel B another of its teeth is caused to engage in the manner described
above.
It may be readily understood that by reversing the action of the
lever L it could be made to operate by hollows instead of pegs on the
barrel B. Moreover, the pegs or hollows acting as above described,
instead of being formed on the cylindrical surface of a revolving barrel
might be formed on a flat travelling surface, and for the purpose of
operating by means of hollows, sheets of metal, cardboard, or other
sufficiently stiff material might in this manner be employed to give the
necessary movement to the lever L, which according to my Invention
as above set forth has not to do the work of striking the string, but
has only to raise the damper and to bring into gear the striking
mechanism.
Having thus described the nature of my Invention, and in what
manner the same is to be performed, I claim,—
First. Working the hammers of automatic musical instruments by
means of a revolving cylinder, the hammer motors being brought into
gear with the said cylinder by means of key levers acted on by pegs or
› hollows on a travelling surface, substantially as herein described.

page_text: preceding claim connecting dampers to the key levers, substantially in
the manner and for the purpose herein set forth.
In witness whereof, I, the said Daniel Imhof, have hereunto set
my hand and scal, this Fifteenth day of January, in the year of
our Lord One thousand eight hundred and seventy-five.