US2466498A - Piano action - Google Patents

Description

` c. F. sMrrH PIANO ACTION April' 5, 1949.

vFilm1 Jan. 1o, `1947 me l nu. um.

www,

Patented Apr. 5, 1949 UNITED STATES PATENT OFFICE PIANO ACTION Charles F. Smith, Forest Park, Ill. Application January 10, 1947, Serial No. 721,195

6 Claims. (Cl. 84-239) The present invention relates to piano actions, and more particularly to a, grand piano action for the bass section of the piano.

While the escapement of the piano actions was improved by the introduction of the repetition lever more than a century ago, this combination has remained substantially the same. The professional pianist develops suiiicient linger strength and endurance to play for long periods, and does not demand any improvement in the vpiano action. The very young players and the average adult players however do not have the power to play for long periods because the action is too heavy or stiff. Consequently some efforts have been made to correct this by the use of counterweights and springs, but at present according to the authorities the usual piano key will be depressed slowly by a weight of 50 grams and will return and lift about 17 grams. A reduction in the difference between the amount of weight required to depress the key and what it will lift will produce a better piano action requiring less nger power. The dynamic range will be greatly extended and the speed of operation will be much higher.

Because of the manner in which the piano action is located in grand pianos, the actions employed by dilerent piano manufacturers of grand pianos are substantially the same. The location of the piano action required by the construction of the grand piano is such that in general the touch of the piano keys of a grand piano is much heavier than that of an upright piano, This difference in the touch between the two piano constructions is particularly noticeable in the bass section. In order to properly balance the piano action in the bass section various counterbalance weights have been inserted in the piano keys. While this produces a balancing action, it also increases the inertia so that the keys in the bass section of the piano cannot be actuated at the same rate of speed as the keys in the treble section.

It therefore would be desirable to provide an improved piano action particularly suited for the bass portion of a grand piano which would have a lighter touch. In accordance with the present invention this is accomplished by two structural features. The one feature employs a spring associated with the hammer stem to lighten the weight of the hammer. The other feature employs an improved support for the knuckle of the hammer stem or hammer butt. By means of these two featured constructions it is possible to provide an improved piano action particularly of advantage in use in the bass section which has reduced friction and a lighter touch.

It is therefore an object of the present invention to provide an improved piano action having a relatively light touch and a high speed of return for the key.

A further object of the lpresent invention is to provide an improved construction which will minimize the friction in the piano action, particularly between the hammer knuckle and the remainder of the piano action.

A still further object of the present invention is to provide an arrangement for reducing the ef. fect of the weight of the hammer in repetition of the sounding of a note.

A still further object of the present invention is to provide a spring arrangement for supporting the weight of the hammer which spring does not require detachment in order to raise the hammer for access to the adjustment of the piano action.

A still further object of the present invention is to provide an improved grand piano action which reduces the inertia of the action as compared to the present employed construction.

Other and further objects of the present invention subsequently will become apparent by reference to the following description taken in conjunction with the accompanying drawing where- 1n:

Fig. l is a fragmentary side elevation of a grand piano escapement action;

Fig. 2 is a fragmentary perspective view of the hammer butt;

Fig. 3 is a partial view of the hammer butt and stem illustrating the manner of supporting the knuckle;

Fig. 4 illustrates the knuckle in action; and

Fig. 5 is a cross sectional View as seen in the direction of the arrows along the 5-5 of Fig. 3.

Referring more particularly to the drawing it will be seen that there has been shown a key frame or base I I which carries a plurality of front key pins I2 each of which is surrounded by a felt washer I3. The base II also carries a balance rail I4 which supports a plurality of balance key pins I5. The keys I6 are held in position by the balance pins I5, and the keys rest upon felt washers Il. The back end of each of the keys I6 carries a felt pad I8 adapted to engage the damper lever which is carried by the damper action bracket or frame I9.

At an intermediate point between the rear extremity of the key I6 and the balance key pin I5, each key I6 is provided with a capstan screw 2|. The capstan screw 2| bears against a felt surface 22 carried by a depending portion 23 of a whip or whippen 24. The whippen 24 is suitably supported at its rear end by a whip flange 25 which is secured by a screw 26 to a whip rail 2l. The whip rail 21 is held in position by a whip rail bracket screw and washer 28 which is secured to the whip flange portion of the action bracket or frame 29. The outer extremity of the whip 24 is connected to an intermediate point on the jack 3| which at an intermediate point carries a jack regulating 3 screw 32. The screw 32 has a jack butt 33 which rests against the whip spoon 34.

The bell crank extremity of the jack 3| is arranged to engage the regultaing button 35 carried by the regulating rail 36 by means of a regulating rail screw 31.

The whip 24 at an intermediate point carries a repetition lever ange 38 which is pivotally connected at an intermediate point to a repetition lever 39. One extremity of the repetition lever 39 carries a repetition lever regulating screw 4| which in turn carries a repetition lever regulating button 42. The button 42 rests upon a felt pad adjacent the rear pivotal connection of the whip 24. The repetition lever 39 carries a repetition vlever spring 43 which engages a loop 44 which is secured to the whip 24. A suitable adjusting set screw is provided for adjusting the tension of the repetition lever spring 43. Adjacent the outer or forward extremity of the repetition lever 39 there is an aperture through which passes the upper extremity of `the jack 3|. Both the jack 3| and the repetition lever 39 engage a knuckle 45 which is carried by the hammer butt 46. The hammer butt 46 is pivotally connected to a butt flange 4l which is mounted in position by a screw 48 upon a butt rail 49 carried by the forward or front portion of the action frame 29. The hammer butt 45 extends rearwardly to a reduced diameter portion known as a hammer stem The hammer stem 5| carries at its outer extremity a hammer 52 which when raised to the dotted line position will strike and engage the piano string 53. When a key is struck and held down the back check 54 carried at the rear end of the key I6 comes into action to limit the downward motion of the hammer 52.

The parts thus far described without reference to any particular type of structure constitute the common grand piano action, with the exception of the fact that particularly in the bass section each of the keys I6 is normally provided with from one to ve weights in that portion of the key extending forwardly of the balance key pins I5.

In accordance with the present invention the usual grand piano action is modied in accordance with the structure shown in detail in Figs. 2, 3, 4 and 5.

The butt 46 carries a knuckle 45 which usually is fastened rigidly with respect to the butt 45. In accordance with the present invention however the knuckle 45 is mounted on a transverse pin member 55 held in position by a pivot pin 56. As is customary the knuckle 45 is generally covered by a piece of firm felt 5l. From the construction shoivn in Figs. 2 to 5 it is apparent that the support block 55 is capable of limited pivotal movement with respest to the butt 46. As may be seen from Fig. 5 the extremities of the pin 56 may be supported in suitable bearing portions 58.

The purpose of providing for limited pivotal movement of the knuckle 45 of the butt 4E of the hammer is to reduce the amount of friction occurring in the relative movement of the hammer and the remainder of the piano action. When the hammer which has been raised returns toward its original position it engages the repetition lever and jack to cause the key |6 to be raised. The engagement of the knuckle 45 with the repetition lever and jack produces a motion of the knuckle 45 in the direction illustrated in Fig. 4 whereby the knuckle moves toward the hammer 52. When the key I6 is depressed,

the knuckle remains in contact with the repetition lever and jack without any sliding action thus greatly reducing the friction at this point of contact. This construction preferably is employed in both the bass and treble portions of the piano.

In the position shown in Fig. 1 the hammer stem 5| rests upon a felt member 59 which is carried by the hammer support 6|. Where a hammer rail is employed instead of individual supports, the felt member 59 is a strip which is notched or grooved so as to receive and hold in position the rear extremity of a spring 62. Into these notches then is tted the rear extremity of the spring 62. Where individual supports 6| are employed the hammer rest is provided with a suitable pin 63 for supporting one extremity of the spring 62. The spring 62 extends substantially the greater portion of the length of the stern 5l up to the butt portion 45. There the spring is wound into a coil 64 of suiiicient power that its effect upon the raising hammer 52 is very nearly constant throughout the movement of the hammer toward the string 53.

From the coil 64 the spring continues up through a suitable aperture in the butt 46 and across the top surface thereof and back down through another aperture until the end of the spring 55 terminates on the bottom side of the butt 46.

The spring 62 carries a considerable portion of the weight of the hammer 52 since the rear end of the spring rests upon the hammer rail 6|. By thus carrying a substantial portion of the weight of the hammer 52 the amount of pressure between the knuckle 45 and the repetition lever 39 at the upper extremity of the jack 3l is greatly reduced. This in turn reduces the amount of friction between these elements and further absorbs a substantial portion of the energy of the descending hammer 52. The spring 62 therefore balances out a substantial portion of the weight of the hammer 52 so that the jack 3| when lifted by the whip 23 need only supply a much lesser amount of power in order to impel the hammer 52 against the piano string 53. The construction of the spring G2 is such that when it is necessary to raise the hammer 52 to a substantially upright position in order to make adjustments onV the piano action as for example adjusting the tension of the spring 43 or adjusting the position of the button 42, this may readily be accomplished without the necessity of disconnecting any spring which operation otherwise might result in changing the action of the spring.

While the spring 62 balances out a considerable portion of the effect of the weight of the hammer 52, enough of the effect of this weight remains to act against the repetition lever 39 and the jack 3| to produce restoration of the key |6 to the position shown in Fig, 1 upon completion of the sounding oi the note.

The combination of the spring 62 and the pivotally mounted knuckle 45 produces an action so that when the repetition lever stops at the adjusting screw in the hammer flange or butt flange 41, the jack 3| may go out in escapelment position and back again without producing a movement of the knuckle 45 on repeated notes.

In the repetition of notes, the knuckle 45 tends to move toward the butt of the hammer so that the jack does not lose contact with the knuckle 45 and does not make a full escapement movement, This produces a reduction in the friction in rapid repetition action.

When however the key I6 is struck and held down, the jack goes into full escapement position, the hammer strikes the string 53 and rebounds on the repetition lever 39 depressing that lever and the hammer is caught upon the back check 54. In this action the knuckle 45 is moved by the point or upper extremity of the jack toward the hammer in the direction illustrated in Fig. 4 whereupon a full escapement movement is produced. The action is such that the jack is responsible for about one-half of the escapement action, and the knuckle is responsible for the rest of the escapement action.

The result of the construction just described is such that there is a noticeably greater ease in pressing the keys at slow speed and a great gain in the operation of the action at a higher speed or repetition of notes.

In adjusting and testing the action of the standard grand piano actions the action is commonly spoken of as being 50 gram weighted. Such an action will permit the key I6 to remain depressed if the key is loaded with a weight of 20 grams. The same action will restore the key I6 against a weight of 15 grams. The application of a 60 gram weight to the key will produce a key action of about 60 times a minute. In contrast to such operation a similar piano action constructed in accordance with the present invention required a weight of 45 grams on the key I6 in order to hold the key down. With a weight of 30 grams on the key restoration of the key occurred at a rate of 200 times a minute. With the application of a 50 gram force to the key the key was actuated 120 times a minute.

In a further comparison of the conventional action against an action constructed in accordance with the present invention it was found that with the application of a certain amount of power it was only possible to produce a repetition in the conventional action of about 288 full strokes per minute whereas in the action embodying the invention 600 full strokes per minute were obtained. This then clearly illustrates the difference in the speed of action which is due to the reduction of friction in the action and the absorption of the inertia energy of the hammer as it rebounds from impact with the piano string.

From the foregoing description and explanation it will become apparent to those skilled in the art that the application of either of the improvements will produce an improved more sensitive piano action. The combination of the two improvements produces the unusual effects indicated by the weight and speed tests.

While for the purpose of illustrating and describing the present invention, a particular embodiment has been shown in the drawing, it is to be understood that the invention is not to be limited thereby since obviously such variations in the construction and in their arrangement may be made as is commensurate with the scope and spirit of the invention as set forth in the following claims.

What I desire to protect by United States Letters Patent is claimed as follows:

1. The combination in a grand piano action comprising a hammer butt carrying on its underside a pivoted knuckle, and a repetition lever and jack arranged to actuate said hammer butt by engagement with said pivoted knuckle.

2. A grand piano action for the bass section thereof comprising a hammer rail rest having transverse grooves therein, a butt rail carrying a butt iiange connected to a hammer butt, said hammer butt being connected to a stem having at the end thereof a hammer, a padded knuckle mounted on the underside of said hammer butt, and a hammer supporting spring having one end secured to said hammer butt in the proximity of said knuckle, said spring having a portion thereof in the proximity of said knuckle wound into a coil, said spring continuing from said coil in a longitudinal direction parallel to the hammer stem, the free end of said spring being mounted in one of the transverse grooves of said hammer rail rest.

3. A grand piano action comprising a hammer rail rest having a plurality of transverse grooves, a butt rail carrying a butt flange, a hammer butt connected to a stem supporting a hammer, said hammer butt being connected to said butt flange, a knuckle mounted on the underside of said hammer butt for limited pivoted movement with respect thereto, and a hammer supporting spring secured at one end to said hammer butt in the proximity of said knuckle, said spring having a coiled portion located in the proximity of said knuckle, said spring extending longitudinally in a direction parallel to said hammer stem and having the free end of said spring portion mounted in a transverse groove of said hammer rail rest.

4. A grand piano action comprising a hammer butt, a knuckle pivotally mounted for limited movement relative to said butt, and a repetition lever and jack arranged to actuate said hammer butt by engagement with said knuckle.

5. In a grand piano action for the bass section having a jack, a repetition lever, and a whip the combination comprising a hammer butt carrying a hammer, a hammer rest, a knuckle pivotally mounted on the underside of said butt, a hammer supporting spring carried by said butt and having one end secured thereto adjacent said knuckle and the other end supported by said rest, and an unweighted piano key for imparting action to said hammer through said jack, repetition lever and Whip.

6. A grand piano action comprising a hammer rest, a hammer butt carrying a hammer, a knuckle mounted on the underside of said butt for limited pivoted movement relative thereto, a hammer supporting spring secured at one end to said butt in the proximity of said knuckle, said spring havin-g a coiled portion located adjacent said end and another portion extending longitudinally in the direction of the hammer with the free end of said spring supported by said rest, a repetition lever, a jack, a whip, and a substantially unweighted key for actuating the hammer and the interconnecting aforesaid components.

CHARLES F. Sli/HTH.

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

UNITED STATES PATENTS Number Name Date 210,223 Plass Nov. 26, 1878 269,405 Gemunder Dec. 19, 1882 1,823,142 Hickman Sept. 15, 1931 1,900,488 Dasenbrook Mar. 7, 1933 2,411,0054 Schulze Nov. 12, 1946

Images