US2452848A

US2452848A - Electric piano action

Info

Publication number: US2452848A
Application number: US537871A
Authority: US
Inventors: James F Goodwin
Original assignee: Individual
Current assignee: Individual
Priority date: 1944-05-29
Filing date: 1944-05-29
Publication date: 1948-11-02
Anticipated expiration: 1965-11-02

Description

NOV. 2, 1948. J oopwm 2,452,848

ELECTRIC PIANO ACTION Filed May 29, 1944 r 3 Sheets-Sheet 1 INVENTOR. ri'ames F: Goodwin ATTDRNEYB Nov. 2, 1948. J. F. GOODWIN ELECTRIC PIANO ACTION 3 Sheets-Sheet 2 Filed May 29, 1944 3 bu ms mm v mm Q .E R m an Q a 3 a 2 k m Q 8 NM Om LT m (7 "h l l l l- |.||"H I N :r: n. r 2. I \m X hm hm mm .3 Q Q Q i E Q m z m K NW W 0 5 my w. w tm ATTORNEYS Nov. 2, 1948.

Filec. May 29, 1944 J. F. GOODWIN ELECTRIC PIANO ACTION 3 Sheets-Sheet 3 wj mwr a ATTDR NEYE Patented Nov. 2, 1948 UNITED STATES PATENT OFFICE ELECTRIC PIANO ACTION James FL Goodwin, Los Angeles, Calif.

Application May 29, 1944, Serial No. 537,871

7 Claims. (Cl. 84246) This invention appertains to improvements in piano actions generally, and more particularly to electrically powered and controlled types thereof.

The invention has among its several objects to provide an action of this class and one that is of extreme simplicity in design and operation, appreciably less expensive to manufacture, and much faster in execution of key movements as compared to the heretofore known or conventional types of such actions.

With these and other objects and advantages of equal importance in view, the invention resides in the certain new and useful combination, construction and arrangements of instrumentalities, parts and circuits, as will be hereinafter more fully described, set forth in the appended claims, and illustrated in the accompanying drawings, in which:

Figure 1 is a fragmentary plan view of a section of the improved piano action, in accordance with the invention;

Figure 2 is a vertical transverse section taken on the line 2-2 of Figure l, and showing a single key unit of the action at a position of rest; 7 Figure 3 is a view similar to that of Figure 2, but showing the changed position of the unit parts upon the depression of the key;

Figure 4 is a diagrammatical view of the electric power and control circuits;

Figure 5 is a top plan view of a circuit and damper control unit associated with each of the keys;

Figure 6 is a perspective view of an angled element or stop for limiting the operative of the circuit closer or controller;

Figure 7 is a, view similar to that of Figure 6, but showing the damper element; and

Figure 8 is another perspective view of an element or pin for transmitting the key movement to the damper for its displacement from string contact.

Referring to the drawings, wherein like characters of reference denote corresponding parts throughout the several views, the embodiment of the invention, as is exemplified therein, is comprised in a foundation, in the form of an angled frame, preferably of wood, that extends the full length of the case (not shown) and is made up of a beam II and a rail l2 rising from its front edge. A standard keyboard (not shown) is dis posed in spaced relation to the front side of the foundation and the keys 13 are individually supported-from the rail I2 by flat steel springs 14. Extending parallel to the rail 12, in the space between it and the inner ends of the keys I3, is a cam-like element l8 that may take the form of a metal rod, oval in cross-section, mounted for turning movements to adjust the tension of the springs 14. The rod 18 has bearing throughout its length on the top edge of a bar or strip 19 that is secured to the front side of the rail l2. The springs l4 have their inner ends secured, as at 15, to the top side of the rail i2 and their forwardly directed ends, as at 16 and H, to the top sides of the keys l3; the securernent H, at the outer ends of the springs 14, having the form of a headed pin that extends downwardly through the keys I3, so that their lower ends project well below the latter, as at H.

Secured in spaced relation with respect to each other along the foundation II and extending transversely thereof are elongated members 26, one for each of the keys 13, the forward ends of the same underlying the latter and their other ends projecting rearwardly and terminating in proximity to respective of the strings S. These members 20 are preferably in the form of metal strips and each constitutes a support for a complete operating unit of the action.

Pivotally mounted, as at 22 and 25, on the lower side of each of the supporting members 20 is a pair of arms 2| and 24 which are, in turn, pivoted as at 23 and 26, respectively, to a rod 21 that has a damper-head 28 afiixed to its rearwardly directed end and normally engaged with its associated string S. The arms 2| and 24 suspend the rod 21 in parallel relation to the lowerside of a supporting member 20, the arm 24 having pivoted connection therewith inwardly from the damper-head 28 and the arm 21' immediately at its forward end. The arm 2|, at its upper pivoted end, is integral with another arm 2 i that extends in substantially right angular relation to the same and has its free end underlying an aperture formed in the supporting member 20 in line with an actuating pin 29 pivotally secured to the under side of a key [3 by means of apertured ears 29', so that when the latter is depressed the pin 29 will likewise depress the arm 21 and cause the arm 2! to move the rod 21 in a direction to withdraw the damperhead 28 from its contact with a string S to free the string for vibration when it is struck.

Rising from each supporting member 20, in rear of the foundation H, is a pair of brackets 30 which support a horizontally disposed solenoid 3| on their upper ends. The movable core 32 of the solenoid 3| has its rearwardly directed end provided with a felt percussion-head 33 and its other or forward end connected through a coiled spring 34 to a rebound damper 35 that is 'seciired to the rear side of the foundation H. The rebound damper 35 is in the form of a metal plate and has a felt pad 35 interposed between it and the opposed side of the foundation ll to cushion the core 32 in its rebound motions.

For controlling the operation of a solenoid 3|, a movable ,contact v3'! is mounted onthe lower side of a supporting member 26 and is comprised in a length of spring metal that is secured at one end to the supporting member and has its other end extending forwardly beyond the foundation H and underlying an aperture 38 formed in the supporting member 28 in line Withthe depending end I I of the securing pin l7 carried by a key 13. Cooperative with the movable contact .3] is a stationary contact 39 that is mounted in the supporting member Zil and insulated therefrom insulation 39.

As is best shown in Figure 4, the electrical connections for the several action units, are as follows:

A .transformer 40 is conveniently mounted within the case (not shown) and is connected to an outside line from a suitable source of current supply. Leads H and 42 extend from the ten minals of the transformer 49 for the parallel connection across the same of the several action units. For each action unit, a branch lead "33 is extended from, for instance, the main lead 4| to the securement l5 of a spring key support M to the foundation rail l2, thus placing the spring support and the securement .pin i1, carried by the key 83, in the circuit. A conductor Ml extends from the stationar contact 39 on'a supporting member 29, and connects one terminal of the coil of a solenoidSi, while the other ter minal of the latter is, in turn, connected by a conductor to theother of the mainleads 42.

In the operation of an action unit as thus provided, Whenever a key i3 is depressed, the extension 17 of the contact pin 17, passes downwardly through the aperture 38 in the supporting member 20 and bears against the free end of the movable contact 3?, closing the circuit therethrough on the stationary contact 35. Current will immediately flow from the transformer as, by way of the main lead iii, the branch conductor the spring support .l i, the contact pin 11 and H to the movable contact 3'5 and through it to the stationary contact 39, from whence it will pass by way of the conductor 44 to one terminal of the coil of a solenoid 3i and from the other terminal of the latter, by way of the conductor to the main lead 32 and back to the transformer 48. With the depression .of the-key I 3, the pin 29, also depending therefrom, strikes the upper portion 2i and depresses it, causing thepivoted arm-2i to move the rod 21 in a direction to withdraw the damper-head 28 from .its contact with a string S, which is then free to vibrate when struck by the percussion-head '33 on the solenoid core .32. After striking the string S, the percussion-head 33 and the core 32 are quickly returned to normal position by the action of the coiled spring 3i, upon the breaking of the circuit between the movable contact 3? and the stationary contact 39. The circuit is completed but momentarily by the initial engagement of the contact pin i7 and H, with the movable contact 3?, since continued depressing motion of the key i3 results in the separation of the latter from the stationary contact-39.

In order to prevent the movable contacty3fl ,Inentintoand out of engagement with the free .end -ofthe movable contact 3 1, during the dc pressing and'lifting motions of the key l3. The other arm 41', of this angled member, is counterweighted, as at 48, to normally hold the depending arms 4! against the edge of the free end of the movable contact 31, when the action unit is inoperative. Thus, when a key I3 is fingered and the movable contact 31 is depressed by the contact pin [1, and H, the depending arm 41 is moved by the gravitational action of the counterweight 48 into the return path of the movable contact 3'! and prevents it from continuing in engagement with the contact pin I! and .H'. The depending arm 41 is withdrawn from the path of the movable contact 31, with the recession movement of the key I3, just before the key reaches its normal position of rest, by theaction of an enlargement 29', formed on the pin 29, which engages the under side of the arm 47 and lifts it .to its normal position.

The upper arm v ll is provided with an apertured enlargement 47" in which the pin 2 9loperates the enlargement 29' of the latter being located below the enlargement Al for its cooperation therewith. Also, the lifting movement of r the pin 29 frees the angled member Zland 21 to allow gravitational movement to the rod'21 for the return of the damper-head 28 into engagement with the string S to check the vibration previously imparted to it by the percussionhead 33.

From this example of the invention, the advantages afforded by its simplicity in .design, construction andassembly will be obvious to those skilled in the art to .which it relates, .it .being particularly noted that there are :but seven .moving parts involved in the makeup ofeach action unit which effects a marked saving in expense of manufacture and upkeep, both with respect to-labor and materials.

Having thus fully described my invention, it is to be understood that various changes in design and arrangement of parts, as well as in minor details of construction, may be resorted to, without departing from the spirit of the invention, or its scope as claimed.

What I claim is:

1. In an electrically powered piano, including a keyboard, an individual actionfor each key and its associated string, said action comprising a stringdamper a rod supporting said damper, a percussion element, a current source, electromagnetic means for actuating the percussion element, a circuit closer cooperative with the key for energizing the electromagnetic means during the initial fingered movement of .the key, arms pivotally connected to said rod means on each key coacting with one of the arms-on said rod for Withdrawing the .damper from the string simultaneously with the depression of said key and with the operation of the percussion element, a coil spring for returning the percussion element-to its normal position of rest the upward movement of said key after its depression releasing the damper :for its return by gravity to its normally engaged position with the string.

2. The piano as in claim 1, with an individual support for each action unit extending in a plane below and rearwardly of a key.

3. The piano as in claim 1, with a foundation mounted in rear of the keyboard and co-extensive therewith, and an individual support for each action unit mounted on the foundation and extending in a plane below and rearwardly of a key.

4. The piano as in claim 1, with means actuated by the key movement for holding the circuit closer on open circuit during the recession movement of the key and to allow a, quick rebound of the percussion element to its normal position of rest.

5. The plane as in claim 1, with means operable with the key during its depression movement for holding the circuit closer on open circuit during the recession movement of the key, said means being actuated from the key in its latter movement to efiect the release of the circuit closer and the damper for their simultaneous return to normal positions.

6. The piano as in claim 1, with the electromagnetic means having the form of a solenoid with the core for efiecting the rebound of the percussion head from striking position.

JAMES F. GOODWIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 962,261 Rose et a1. June 21, 1910 1,148,719 Sandell Aug. 3, 1915 1,562,103 Little Nov. 17, 1925 1,603,871 Sandell Oct. 19, 1926 1,691,295 Little Nov. 13, 1928 2,007,302 Miessner July 9, 1935