Improvements in Tempo Indicators and Governors for Mechanical Musical Instruments.
Year: 1898

page_text: Date of Application, 25th June, 189. Accepted, 13th Aug., 1898
[Communicated from abroad by THE AEOLIAN COMPANY, a corporation organized
under the laws of the State of Connecticut, and having its place of business
at 18, West 23rd Street, New York, United States of America.]
Improvements in Tempo Indicators and Governors for Mechanical
Musical Instruments.
I, WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake & Co., Patent Agents,
45, Southampton Buildings, in the County of Middlesex, 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:-
This invention relates to an improved tempo indicator and governor for musical
instruments.
In the accompanying drawings Fig. I is a transverse vertical section of a
musical instrument embodying my improvements.
Fig. II is a detailed top view of my are shaped chronometric scale, my combined
tempo indicator and hand lever, my valve box with its peculiar opening and slid-
ing throttle valve and the connecting and co-operating parts.
Fig. III shows peculiar form of opening in valve box and working of valve
on said opening.
Any parts occurring in two (or more) views are indicated by the same numerals
of reference.
The application of these improvements extends to all forms of pneumatic musical
instruments, such as the acolian, wherein the sounding devices are controlled
automatically by a perforated music sheet, the rate of travel of said music sheet
determining tempo of music.
The object of my invention is to provide not only means for regulating flow of
air from the motor to the bellows but also for causing the movement of the con-
trolling lever to indicate the speed at which music sheet is moving. Numbers on
scale corresponding to numbers on music sheet, serve to determine the correct
chronometric movement of said music sheet.
A great advantage of this invention is that by the use of few parts and only
slightly movable connections I secure a reliable movement of valve and a quick
response to the movement of the indicator lever.
One end of the music sheet is permanently secured to its spool which is placed
in a holder 1. The free end of the sheet is then detachably secured to the take up
roller 2 which is engaged by a gear upon pulley 3 driven by belt 4 from pulley 5
upon pneumatic motor employed to propel music sheet. This motor is supplied
with air or exhausted through the opening 6 of the upper supply chamber 7,
the sliding throttle valve 8 working over the peculiarly shaped opening 9 and
thereby regulating and controlling the amount of air passing or exhausted through
said opening, and thereby governing speed of said pneumatic motor.
The govern-
ing sliding throttle valve is connected to and impelled by the lower arm of a
rock shaft 10, the upper arm of which is, in turn, connected to a rod 19 which is,
in turn, connected to the short arm of a bell crank lever 11; the outer end of the

page_text: long arm of the latter serving both as an indicator, and as a hand lever for operating
the valve.
To allow of fine adjustment of the valve to the movement of the indicator lever
the upper arm of the rock shaft 10 is not fixed firmly to the rock shaft but is
provided with a collar 12 which is fitted to the rock shaft and provided with a set
screw whereby it may be secured to the rock shaft in different positions.
The operations of my improvements are substantially as follows:
"
Suppose the music sheet to have the numerals "50," 20" and "85" marked
upon it, and that the roller is placed in the instrument. The performer to start
the piece at the proper tempo moves the indicator along the scale until it reaches
"50" on the scale. As the indicator is also a lever for operating the valve this
causes the valve 8 (see Figs. I, II and III) to move along and uncover part of
opening 9 as shown in Fig. III. The motor is now left to run at this moderate
rate of speed until the next numeral "20" appears when the performer moves
indicator back to "20" on the scale, thus lessening the rate of speed of motor and
consequently reducing the tempo. Again when the numeral 85" appears on
the sheet, the performer moves the indicator along the scale, and the speed of the
motor increases steadily until about "80" is reached when, owing to the peculiar
shape of the opening 9, the wider portion b of said opening (Fig. III) is suddenly
uncovered and a full speed of motor is attained.
"
Thus by moving the indicator slowly along from zero up the scale you secure
a gradual but steady quickening of the tempo until about "80" is reached when
the wider portion is uncovered and the full speed of the motor is instantly attained.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, as communicated to me by
my foreign correspondents, I declare that what I claim is:-
1. In a musical instrument wherein the sound producing devices are controlled
by a travelling music sheet or like device, a pneumatic motor for propelling said
device, a throttle valve for said motor, a scale for indicating tempo and a con-
trivance serving as a pointer for said scale and as a direct controller of the throttle
valve.
2. In a musical instrument wherein the sound producing devices are controlled
by a travelling music sheet or like device, a pneumatic motor for propelling said
device, a throttle valve for said motor, a scale for indicating tempo and a bell crank
lever one of whose arms serves as a pointer for said scale and as a handle and the
other of whose arms serves to actuate the said valve.
3. In a musical instrument wherein the sound producing devices are controlled
by a travelling music sheet or like device, a pneumatic motor for propelling said
device, a throttle valve for said motor, a scale for indicating tempo and a contri-
vance serving as a pointer for said scale and as a direct controller of the throttle
valve, said valve being provided with an opening shaped so as to permit of a
gradual increase in the volume of air to a certain point and to suddenly increase
the volume of air at another point.
4. In a musical instrument wherein the sound producing devices are controlled
by a travelling music sheet or like device, a pneumatic motor for propelling said
device, a throttle valve for said motor, a scale for indicating tempo and a contrivance
serving as a pointer for said scale and as a direct controller of the throttle valve, an
adjustable connection being provided between said contrivance and said valve.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.