US1603871A

US1603871A - Piano-playing device

Info

Publication number: US1603871A
Application number: US568226A
Authority: US
Inventors: Henry K Sandell
Original assignee: Mills Novelty Co
Current assignee: Mills Novelty Co
Priority date: 1922-06-14
Filing date: 1922-06-14
Publication date: 1926-10-19
Anticipated expiration: 1943-10-19

Description

H. SANDELL PIANO PLAYING DEVICE Filed June 14, 1922 4 Sheets-Sheet 1 727'2677557 fiZZ WE fiarmeli,

Oct. 19 1926.

H. K. SANDELL PIANO PLAYING DEVICE Filed June 14, 1922 4 Sheets-Sheet 3 "mum Oct. 19 .1926.

H. K. SANDELL PIANO PLAYING DEVICE 4 Sheets-Sheet 4 Filed June 14. 1922.

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no QQ Patented Oct. 19, 1926.

UNITED STATES 1,603,871 PATENT orries.

HENRY K. sANnELL, or GKICAGO, rumors, essrenon To 1vIILLs NOVELTY ooM- PANY, OF CHICAGO, ILLINOIS,

A CORPORATION OF ILLINOIS.

PIANO-PLAYHVG DEVICE.

' Application fi1ed June 14,

The present invention relates to improvements in piano playing devices, and more particularly to such devices operated by means of an electrical current and controlled by perforated note sheets or bymanually operated keys, as desired. It will be fully understood from the following description of an embodiment 'of' the invention, illustrated by theaccompanying drawil'igs, wherein:

Figure 1 isan elevation of a piano playing device embodying the present invention, the central portion thereof being broken away;

Fig! 2 is an end elevation of the piano playing action illustrated in Fig. 1, show ing in detail thev operation of a note-plays ing magnet and of the control magnets for the dampers;

Fig. 3 shows in detail a sectional View through the control magnets for the control of the hamn'ier-rail;

Fig. 4 shows in plan the control magnets of Fig. 3;

Fig. 5 is a sectional View through the action on the line 5-5 of Fig. 1, showing in detail a note playing' action and the control magnets for the operation of the hammer-rail;

Fig. 6 is a sectional view through a noteplaying magnet; and

Fig. 7 is a diagram'inatic view sliowing the circuits for the control of the various parts of the piano action both from a perforated note sheet and from manually operated keys and pedals. I

Referring more particularly to the drawings, the numeral 10 indicates the string plate of a piano, which may be, for example, of the character described and shown in my prior Patent No. 1.028.496 granted June i. 1912. The strings are indicated' by numeral 11. The actions for the individual keys are designed by numeral 12 and, as they do not form a part of the present invention, are not described in further detail herein. The action of each key is con trolled by a riser 13 acting against the jack butt 14 and actuated by an alternating current note-playing magnet 15, the construction of which will be further hereinafter described.

The length of stroke of the hammers is controlled lt y the position of the movable hammer-rail 16 carried by arms Ur manna 1922. Serial- No. 5622226.

ed on pivots 16 which are supported on the bracket 16. A. spring 16 tends to draw the han'im'er-rail towards the strings. At one end of the hammer-rail 16 a pin 17 pro ects, this pin being preferably covered with a felt roller 17 The pin 17 engagesone end of the hannner rail operating lever 18, the other end of which is engagedby the felt-covered head 19 of rod 20, operated by the movable core of control magnet 21. By the operation of the control magnet 21, the rod 20 is operated either to force the hammer-rail 16 back to its farthermost position to give a full stroke to the hammers 22, or

is permitted to assume an intermediate position, correspondingly reducing the stroke of the, hammers.

A second magnet 23 cooperates withthe magnet 21 and the rod 20 to hold the rod in its extended position. eration of this co-operating magnet will be clear from Figures 3 and 5; Figure 3 sl1o-W- ing the magnets and their co-operatin'g parts 'in detail.

liiagnet 21- is" formed as a coil or spool 24: of suitably insulated wire, in the center of which is the movable core 25-. The coil 24 is formed on a cylinder of suitable nonmagnetic material 26. At one end of the coil a cylindrical member 27 projects into the opening through the coil, the inner portion of this member being formed to provide a seat for the end of the core 25. which may suitably be provided with a felt bushing 28 to deaden the sound of impact. A laminated iron frame 29 of generally rectangular form completely surrounds the magnet undue heating thereof being prevented by' its laminated construction. The

rod 20 is secured to the end of the core 25 and passes through a suitable bore in the member 27 and in the end of the frame 29, a felt bushing being provided-to" eliminate noise. At the end of the rod '20the head 19 is mounted; being provided at. its end with felt pad 3-1, which engages the hammer-rail operating lever 18. Back of the head 19' is mounted a felt washer 32 on the rod 20, the purpose of which will be clear from a consideration of the operation of the (to-operating control magnet 23.

Magnet 23 is mounted within' an iron frame 33'which is mounted to a suitabledepending supporting member 3% secured to the frame 29 of magnet 24:; Within the The mode ofjjopcylinder 35. At its upper magnet 23 is mounted a cylinder of suitable non-magnetic material, for example, brass. A core or armature 36 is movably mounted within the cylinder 35. At its lower end the core 36 is provided with a projecting rod portion 37 which passes through a felt bushing 38 in a suitable bore provided in the cap 39 closing the lower end of the cylinder 35. A coil spring 40 in the lower end. of the cylinder surrounds the rod-like projection 37 and bears against the end of the'core 36, tending to force it upwardly. At its upper end the core 36 is provided with another rod-like projection 41, which passes through a felt bushing 42 in the cylinder 35 and also through a felt bushing 43 in the cap 44 closing the upper end of the end the projection 41 is provided with a felt head 45, which normally bears against the felt head 32 mounted upon the rod 20 operated by magnet 21.

The co-operation of the two magnets will be readily apparent from a considerat on of Figure 5. When the electromagnet 21 is momentarily energized by alternating current, the solenoid core 25 is forcibly brought to the center of the magnet and the rod 20 is actuated to push the end of the hammerrail operating lever 18. By this movement the felt pad 32- is brought to such a position as to entirely clear the felt head 45 on the rod 41 operated by electromagnet 23, and the spring 40 in the latter magnet, acting on the end of the core 36, forces the rod 41 and the felt head 45 upwards against the rod 20 between the pad 32 and the frame 29. The elements are then in the position shown in Figure 5. Upon deene-rgizing the magnet 21, the head 45 then serves as a stop preventing the return of the head 19 of rod 20, and thereby prevent the return of the hammer-rail operating lever 18 to its normal position. A momentary closure of the circuit energizing the magnet 21 consequently results in placing and holding the rod 20 in energized position, its position being maintained even after the magnet 21 has been dc-energized. With the parts in this position, energizing the magnet 23 causes a retraction of the core 36 to the center of the magnet. This draws the head 45 back to a position such as to clear the pad 32 on rod 20 and permit the latter to return to its normal position with the magnet 21 de-energized. By means of this arrangement, for example, if the magnets are operated from a perforated music sheet, a single perforation will permit closure of the circuit energizing the magnet 21 and the parts operated by the magnet will be held in the position after the magnet is de-energized until a perforation permitting closure of the circuit through magnet 23 energizes the latter. The'hammer-rail lever 1.8 is then permitted to return to its normal position under the action of its spring 16 Dampers 46 are lifted from the spring to produce the pedaling effect by the lever 47 which is operated by a pair of

co-operating magnets

21 and 23 of substantially the same type of construction as

electromagnets

21 and 23, and co-operating in substantially the same manner. In these electromagnets, as shown in Figure 2, the various elements are indicated by the same numerals that indicate corresponding elements in the

electromagnets

21 and 23 in Figures 3 and 5, the suffix a being added to the several numerals. It will be apparent that a momentary energizing of the magnet 21? will operate the lever 47 to lift the dampers 46, and the latter will be retained in the lifted position by co-operation of the magnet 23 until the latter is momentarily energized.

The cores of

magnets

21 and 21 are preferably of laminated construction, as shown in Figure 4, undue heating thereof being prevented by this laminated construction.

The construction of the individual noteplaying magnets 15 will be clear from a consideration of Figure 6. Each of these magnets is formed of a spool 48 of suitable insulated wire mounted in a metallic, preferably iron frame 49. Within the. spool is a tube or hollow cylinder 50 of non-magnetic material, preferably brass. Slidably mounted within this tube is the magnetic core member 51, provided at its ends with

rodlike projections

52 and 53. The rod-like projection 53 passes through a bushing 54 in the cap 55 in the lower end of the tube 50 and serves as a guide for the movement of the core. The rod-like projection 52 passes through a similar bushing 56 in the cap 57 in the upper end of the tube 50. The rod-like projection 52 is provided at its upper end with a head 13 and acts a riser for operating the piano action, as shown in Figures 2 and 5.

As willbe seen from Figures 1. 2 and 5. the note-playing magnets 15 are arranged in rows. each row of magnets heinfr mounted upon an angle bar 5O extending transversely across and parallel to the string frame. The angle bars 50 are insulatably mounted upon the supporting braces 51, the insulation being indicated 52 A. channel bar 53* is insulatably suspended from each angle bar 50 and is lined with insulating material. such as fiber, indicated at 54. A panel 55 of insulating material serves as a cover for this channel. bar, which is used as a conduit for the electric cables controlling the individual notes. nals 56 are provided on the panels 55. to which are connected one of the terminal leads from each of the note-playing electromagnets, the control lines for the corresponding notes being connected to the cor- Termipreviously described.

responding terminals inside the channel box or conduit 53. The opposite terminals of the note-playing electromagnets are directly connected with the angle bars which serve as a common connecting line for-all the electromagnets.

The operation of the various circuits controlling the mechanical devices of the piano willbe clear from a consideration of Figure 7. In this figure the various parts are shown diagrammatically, the parts and electromagnets corresponding to those hereinbeforc described being indicated by thesame reference numerals. Two main connections and 61 are provided for the supply of alternating current for the operation of the instrument. The line 60 is directly con nected with the contact roller 61, over which moves the perforated note sheet 62. Cooperating with the contact roller 61 and the note'sheet 62 are a plurality of contact members 63 controlling the note magnets 15. Other contacts controlling the expres sion devices and the volume of sound are provided, as will be hereinafter described. From each contact 63 a connector 4 leads to a point of connection 56", with which is connected a terminal line from the corresponding note-playing magnet 15. The other terminals of the note-playing magnets are all connected to a common connector or line 50, corresponding to the angle bar 5O The line 50 is connected with a coil 66 which, in turn, is connected through line 67 with the other cur rent supply line 61. The switch 84 is opened in playing by means of a perforation in the note-sheet. It will thus be apparent that when a perforation in sheet 62 corresponding to a given note passes between a contact 63 and contact roll 61, current will pass through that contact to the corresponding note-playing magnet 15, the connector 50", the inductance 66 and the line 67 to the outlet line 61. The fixed inductance of the coil 66 will determine the force with which the core of the note-playing magnet is centered and consequently will determine the volume of sound of the note.

For varying the loudness of tone additional means closed by circuits through the contact roller 61 are provided. For clecreasing the current and for correspondingly decreasing thevolume of sound, a contact 68 is provided, which, when it engages the contact roller 61, closes a shunt circuit through the line 69 and the coil 70 to the line 67. The coil 70 is wound in the same direction the coil 66 and closure of this circuit consequently increases the inductance and decreases the current through the note-playing electromagnets through which fllICllltS are closed from thecircult through Contact 68. For producing a greater volume of sound, a contact 71 is provided, which,

when itengages contact roll 61 through a perforation in the note sheet provided for the purpose, closes a shunt circuit through the line 72 and the coil 7 3 to the line 67. The

coil 73 is Wound in a reverse direction to the coil 66 and consequently when current is passed through coil 7 3, the inductance is decreased and the current actuating the electromagnets 15 energized while the current through contact 71 is closed, is greater than 61. A single perforation in the note sheet,

causing a momentary energizing of the electromagnet 21 is sutlicient, as has been previously explained, since by co-operation of the core of electromagnet 23, the core of magnet 21 is held in position until magnet 23 is energized. l/Vhen contact 75 engages contact roll 61' through a perforation in the note sheet, a circuit is closed through line 79 and electromagnet 23, which is energized to retract its core and release the core of its electromagnet 21 in the manner previously described. The damper control magnets 21" and23? are controlled in similar manner from

contacts

80 and 81, respectively. The line leading from contact 80 to electromagnet 21 is indicated by numeral 83 and that leading from contact 81 to electromagnet 23 is indicated by numeral 82.

In Figure 7 circuits are diagrammatically shown for the control of the piano playing devices from keys and pedals such as are in use in'ordinar'y pianos. lVhen it is desired to use the manual and foot operated controls instead of the note-playing keys, the switch 84 is closed, thereby esta-blishinga connection between the line 50" and the line 67 shunting out the inductance 66. The noteoperating keys are indicated diagrammaticallyin end elevation at 85. 'The base ot each key is connected by a line 86 with the terminal 56" of: the corresponding note-playing magnet 15. Below each key are mounted two coil springs, a longer spring 87 and a shorter spring 88. The

springs

87 and 88 serve as contact members, the spring 87 being engaged by the base of the ltey on a. slight depression of'the latter and the spring 88 being engaged on a more forcible depression of the key. Each of the contact springs 87 'is directly connected with a common connector 90 leading to a coil or inductance 66 which is in turn connected through line 91 with the contact roller 61 The inductance 66 plays the same role in modulatin the sound produced by the electromagnets being the 88 and the base of the hey is closed, it isthus apparent that the inductance 66 is shunted around with a corresponding increase in current through the electromagnet 15 being energized and resulting increased volume of sound.

To soften the tone during manual operation, the pedal 93 may be employed. This pedal is connected to i c main conductor 61 by a connection When the pedal is depressed, it engages a contact 95, closing a circuit through the line 96 and coil TO to the line 91. The coil being Wound in the same direction as the coil (56, increases the inductance in the latter and thereby de creases the current passing to thenote-playing electromagnet 15 being energized at the moment. The operation ot the pedal 93 and the coil '70 thus corresponds tothat ot the contact'68 and the coil 70 in operation with the note sheet. a

The pedal'97 controls the ene'gizing ot the damper operating magnets 21? and Vith the switch 98 closed, the pedal is connected to the main line (31. Normally the end of the pedal 9? engages contact thereby closing the circuit through the line '100, line 83 and electromagnet 28. On depressing p dal 97 circuit through the contact 99 is opened and circuit through the contact 101 is closed. Current then passes through the connecting line 102 and line 82 to electroma gnet 21 energizing the latter to raise the dampers 46 from the strings. Release of the pedal 97 breaks the circuit through contact 101 and immediately makes the circuit through contact 99, thereby immediately energizing the electromagnct 23* and releasing the damper.

I claim:

1. In a piano action, in combination, hammer actuating mechanism, a magnet coil, a freely movable core within the coil normally out of central position therein, ,mea .s for supplying alternating current to said magnet coil, thereby bringing said core to central position, means operated by the movement of the core to operate the hammer actuating mechanism, a coil in the circuit in series with said magnet coil for determining the inductance in said circuit and means for varying the inductance of said second-mentioned coil to vary the current passing through said n'iagnet.

2. In a piano action, in combination, hammer actuating mechanism, a magnet coil, a freely movable core Within the coil nornally out of central position therein, means for supplying alternating current to said i 7 1st coil, thereby bringing said core to central position, means operated by the movement of the core to operate the hammer mechanism, a coil in circuit in series with said magnet coil for determining the inductance in said circuit, a coil inductively coupled With said second-mentioned coil and wound in the same direction and independently controllable means for passing alternating current through the lastmentioned coil to increase the inductance in the former coil,

3. In a piano action, in combination, hammer actuating mechanism, a magnet coil, a freely movable core Within the coil normally out of central position therein, means for supplying alternating current to said magcoil, thereby bringing said core to central position, means operated by the movei'uent of the core to operatethe hammer acuiechaniiim, a coil in the circuit in series said magnet coil for determining the n hi ance in said circuit, a coil inductively coupled with said second mentioned coil and 'u'ouu d in the reverse direction, and indcpendentiy controllable means for passin at .irnating current through the lastmentioned coil to oecrease the inductance in the tormer coil.

l. In a pianoaction, in combination, hammer actuating mechanism, a magnet. coil, a "freely movable core Within the coil normally out of central position therein, means for supplying alternating current to said magnet 0 il, "hereby bringing said core to central position, means operated by the movement of the core to operate the hammer actuating mechanism, a coil in circuit in series with said magnet coil tor det rmining the inductance in said circuit, coils inductively coupled with said first-mentioned coil, one

of said coils being Wound in the same direction and the other in the reverse direct1on, and independently controllable means for passing alternating current through the last-mentioned coils to vary the inductance in the'first-mentioned coil.

5. In combination with a piano action, hammer actuating mechanism therefor comprising single electromagnet coils for each hammer of said action, a freely movable core in each of said coils, said cores being normally out of central position, a common connector for one of the'terminals of each of said electromagnet coils, a coilin series with said common connection, independent connectors for the other terminals of each of said coils, and independently controllable means for closing the circuits through said last-mentioned connectorsto supply alternating current to the electromagnet coils, to thereby bring their cores to central position, and means operated by the movement of the cores of the magnets to actuate the corresponding hammers of the piano action.

6. In combination with a piano action, hammer actuating mechanism therefor comprising single electromagnet coils for each hammer of said action, a freely movable core in each of said coils, said cores being normally out of central position, a common connector for one of the terminals of each of said electromagnet coils, an inductance coil in series with said common connector, separate connectors for the other terminals of said coils, independently controllable means for closing a circuit through each of said separate connectors to supply alternating current thereto, to thereby bring the cores to central position, means operated by the movement of the cores of the magnets to actuate the corresponding hammers of the piano action, and means for varying the inductance of the coil in series With the common connector to vary the force of movement of the hammers.

7. In combination With a piano action, hammer actuating mechanism therefor comprising single electromagnet coils for each hammer of said action, a freely movable core in each of said coils, said cores being normally out of central position, a common connector for one of the terminals of each of said electromagnet coils, an inductance coil in series With said common connector, separate connectors for the other terminals of said coils, independently controllable means for closing a circuit through each of said common connectors to supply alternating current thereto, to thereby bring the cores to central position, means operated by the movement of the cores of the magnets to actuate the corresponding hammers of the piano action, an additional coil inductively coupled With the coil in series With the common connector, and means for passing alternating current through the last-mentioned coil to vary the inductance in the circuit through the electromagnets.

8. In combination with a piano action, hammer actuating mechanism therefor comprising single electromagnet coils for each hammer of said action, a freely movable core in each of said coils, said cores being normally out of central position, independently controllable means for supplying alternating current to each of said electromagnet coils, to thereby bring the cores thereof to central position, means operated by the movement of the cores of the magnets to actuate the corresponding hammers of the piano action and means for varying the inductance in the circuit of said electromagnet coils to vary the strength of current passing therethro-ugh.

9. In a piano playing device, incombin'ation With a piano action, alternating current magnets for actuating the individual hammers of said action, and a circuit for the control of each of said magnets including a manually operable key, contact means closed by partial movement of said key for closing the circuit and contact means operable on further movement of said key for reducing the inductance in said circuit.

10. In a piano playing device, in combination With a piano action, alternating current magnets for actuating the individual hammers of said action, and a circuit for the control of each of said magnets including a manually operable key, contact means closed by partial movement of said key for closing the circuit and independently controllable means for increasing the inductance in said circuit.

11. In a piano playing device, in combinaQ tion with a piano action, electromagnet means for actuating the individual hammers of said action, and a circuit for the control of each of said magnets including a manually operable key, contact means closed by partial movement of said key for closing the circuit and contact means operable on further movement of said key for varying the current in said circuit.

HENRY K. SANDELL.