US1646001A - Expression mechanism for mechanical musical instruments - Google Patents

Description

' 1, Oct. 18,1927. ETOWER 646001,

EXPRESSION MECHAI IISM FOR MECHANICAL MUSICAL INSTRUMENTS- Filed March 5, 1926 '2 Sheets-Sheet 1 VENT R. WITNESSES; m 0

0 t. 18,192. c 7 H. E TOWER EXPRESSION MECHANISM FOR MECHANICAL MUSICAL INSTRUMENTS Fil'ed March 3. 1926 2 Sheets-Sheet 2 rr==m Patented Oct. 18, 1927.

UNITED STATES PATENT. OFFICE.

unnsonnnnmownn, or- CINCINNATI, onrqnssreuon TO THE BALnWINcoMPANY,

onoINoINNA'rI, OHIO. V v p r Y nxrnnss on mncniANIsM 'Fo'a MECHANICAL Musician ms'rnunnivcrs.

" Application filed March 3, 1926; Serial No. 91,982.

The expression mechanism for controlling the degree of tension in the chests of player actions that are used for operating the notes of a piano have been made ofvarious kinds,

but have allbeen so complicated and "hard to regulate that the ordinaryrepair manor regulator could not regulate them. The

"present invention is made so simple that any onecanregulate it to give the proper degrees of control and it 1s also made to'change the degrees so quickly and with such a short motion of the governor spring that therewill be no wear and no lessenlng of the tenslon of this spring by constant stretching.

A further object of my invention 1s to have a mufiier that will allow the air to be drawn the .player action To create a partial vacuum in the player into the chests to reduce the tension and yet be quiet and will not be clogged With dust from long usage.

In the drawings Figure 1 1s a "front view of a mechanical musical nstrument showmg the pump, electric motor, expression mechanism and the player action. Flgure 2 1s a top view of the expression mechanism with the muffler removed. Figure 3 is a top view of the mufller showing how it is slit to break up the air currents. Figure 4 is an end view of the expression set showing how the muffler is held in place. Figure 5is a cross section takenalong line A-A ofFigure 2.

A player action 1 has a roll box 2 with a trackerbar 3 for controlling the action of the pneumatics 4 as the music'roll 5 forward by theair motor 6. Besides the regular note holes 7 in thertracker bar 3 there are a number of expression control holesS, 9, 10 and ll'for controlling the ac tion of a number of pneumatics12, 13, 14- and a pneumatic pouch-15, whichvact on areverse lever 16 that controls the action of a spring 17 whichis connected to a valve rod 18 that carries a valve 19, which valve 19 1s used to control the degree of a1r tension in action 1 for actuating the pneumatics 4, and

in the air motor 6 that drives the music roll 5, a pneumatic pump 20 is driven by an electric motor 21 at such speed as to give the maximum tension needed. The pneumatic pump 20 is connected to the player actlon 1 by a service hose 22, and to the control box 23 by a hose 24. It is also connected to the air motor 6 by a suitable hose whlch is not shown.

is drawn I The pneumatics'12, 13,14 onflthecontrol box 23 are each controlled by separate valves 25, 26, and'pouches-28, 29 and 30. The pneumat1c pouch 15 is controlledxby a valve 31' and a pouch 32. These pneumatics 12, 13, 14 are adapted to press down on thereverse lever 16 by means of arms 33, 3-4 and 35, whereas the pneumatic pouch l5 act's-directly on thevalverod 18 from below and closes the valve 19. i

vings 3810f different size that act insidelofwa felt lining 39 in the port hole 37' to breakup the currents of air" that go through the port hole 37 to reduce the air tension in the player action. To further reduce the'noise ofthe arr passing through the port hole 37 a cover 4051s made to fit over all the neumatics-and the control valve 19. This cover 40 is made with a plurality of long narrow slots'52 in the top thatact to break up the aircurrents vandit'is also covered withza heavy'layer of felt 41. For easyaccess to the regulating controls this cover is held in placeby .a' pair of latches 42 that hook over pins provided on the ends of the cover. j

To control the action ofthe pneumatics' 12, 13, and .14 on the reverse lever 16, a number of-stop screws'43, 44 and 45 are set in the movable leaves of these pneumatics to limit the length of the stroke. Spring'l? is 's'et into the reverselever andheld in place by a p1n46, which pln-is also used for regulating the tension of the spring-17.

The control holes, 8, 9, 10, 11 in the tracker bar 3 are connected to the pouches 28, 29,30 and 32 by means of tubes 47, 48, 49 and 50 and the valve 31 is connected to the pneumatic pouch 15 by a tube 51. i

When the electric motor 21 is started, it.

drives the pneumatic pump 20 causing a partial vacuum in the player action 1, control box 23 and air motor 6. If this pneumatic pump is operated fast enough to cause a vacuum of 40 inches water gauge, the notes will operate to bring out a very loud tone in the musical instrument. gree of vacuum the control valve 19 is set inside the vacuum chamber of the control To vary this deboxi23 and covers the port hole 37. The effect of this vacuum is to pull the control valve 19 away from the port hole 37 allow ng atmospheric air to leak in until the tension of the air in the control box 23 and the player action 1 is balanced with the tension of the spring 17.

To be able to raise the tension of the air from the minimum governed by the spring 17, 1the pneumatics 12, 13, and 14: are set to ull down on the reverse lever 16, thereby 7 increasing the tension'of the spring 17 and raising the tension of the air inside the player action 1 and control box 23. The minimum tension is set by the balancing of vthe spring 17 and the valve 19, at about 6 inches water gauge. lVhen an-opening in the music roll5 uncovers the hole 8 in the tracker bar 3 the air is allowed to go through the tube 47 and operate the pouch 28, which 7 I will then operate the valve 25, causing the pneumatic 12 to collapseuntil the regulating screw 43 has touched the bottom board of the pneumatic. This regulating screw 43 is set so that when'the arm 33 presses the reverse lever 16 down the spring 17 will be stiffened enough to raise the tension to 9 inches water gauge. WVhen the control opening 9 is uncovered, the air operates through the tube 48, pouch 29 and valve 26 to collapse the pneumatic 13 to cause the block 3 1 to press down the reverse lever 16 until the regulating screw 14: strikes. is setv so; that the lever can be pulled down to give a tension of 12 inches Water gauge.

The action of the Pneumatic 14: is controlled in the'same manner through opening 10, tube 49,pouch 30 and valve 27. The regulating screw is set so that the reverse lever 16 stiifens the spring 17 to give a tension of 15 water gauge.

When the control opening 11 is uncovered :the' air-is admitted through tube to pouch 32 that opens valve 31, admitting air through tube 51, to the pneumatic pouch '15, which pouch 15 will be drawn up by thevacuum insidelthe control box 23 and presson the valve rod 18'pressing the valve 19 against the seat around the port hole 37.

When this valve 19 is tight against the seat This screw 44:

around the port hole 37 there will be no leakage and the air tension will rise in the player action and the control box 23 up to the maximum being created by the pneumatic pump'20.

As the 'movement of the spring 17 to change the pull on the valve 19 is very slight and due to the action of the pneumatic pouch 15 in helping to close this valve 19 at the highest, tension, there is no breaking down of the'springfrom excessive stretching.

With this action of all parts being made to move only a short distance and the ability to regulate this distance by only removing the mufl'ler 10, the regulation can be adjusted to give the exact degree very quickly, also the action of these parts when operatingis so fast that the t-ension can be raised to the desired degree almost instantly to. strike a melody note and yet'can drop back at once so asnot to raise the tension of the accompaniment notes.

Many modifications can be made, but what I claim'as my invention 1s:

1. In a mechanical musical instrument, a

pneumatic action, a power unit for creating a maximum degree of suction to actuate the said pneumatic action; anexpression action comprising a relief valve, a port and a spring for controlling the suction of air created by the said power unit to a number of dilferent degrees, the said spring so connected as to be stiffened by a number of pneumatics and separate means acting directly on saidrelief valve for closing off all ncomingair through HERSCHEL E. TOWER.

Images