US2419174A - Piano action - Google Patents

Description

Patented Apr. 15, 1947 PIANO ACTION Francis 0. Socin, St. Charles, 111., assignor to The Rudolph Wurlitzer Company, Chicago, 111., a

corporation Application July 21, 1944, Serial No. 545,902

(Cl. S4-240) 2 Claims.

This invention relates to a piano action, particularly relating to the hammer actuating jack and associated elements.

In the usual piano action the free end of the jack loosely abuts the hammer butt for forwardly impelling the hammer. Following this action, however, the free end of the jack slides to the rear of the butt and thereupon becomes ineffectual for actuating the hammer until it returns to initial position upon the key being released. By reason thereof such piano actions do not have the double repetition action available in grand pianos, wherein the hammer is operable through intermediate ilnger actions on the key. It is, therefore, the purpose of thisinvention to provide a flexing jack which is tied permanently in flexing engagement with the hammer butt so as to be at all times effective in actuating the hammer during intermediate positions of the key, resulting in the desired greater repetition action. This is accomplished by pivotally connecting the free end of the jack with the hammer butt through a link operable in the manner to be hereinafter more particularly described.

A further feature and advantage of the invention resulting from the linked connection between the jackand the butt resides in an action wherein the usual bridle tape and bridle wire are eliminated, the design of the butt and means for obtaining escapement of the hammer from the string being substantially changed from that usually employed. The pivotally linked jack provides escapement of the hammer from the tring when the contact button is engaged-by the jack making it unnecessary to provide the usual butt knuckle and bridle tape such as to provide greater repetition in the action. Thus, the usual jack spring will return the linked jack to effective position upon partial release of the piano key after strikmg.

A further feature of the invention resides in an adjustable back check which may be attached directly to the butt for checking the backward throw of the hammer and prevent any secondary rebound of the hammer toward the string.

It may also be noted that by reason of this improvement the action will not be blocked either by the packing of the front rail key punching, or by compression of the back check cushion as occurs in the usual action. It also has the effect of eliminating the friction of the jack on the butt knuckle, and the necessity of regulating the back check and bridle tape.

The full nature of the invention will be understood from the accompanying drawing and the following description and claims:

Fig. 1 is a sectional view through a piano action showing a unit thereof with a portion of itsa'ssociated actuating piano key in normal position.

Fig. 2 is thesame as Fig. 1 showing the action in key actuated position.

Fig. 3 is anenlarged section of the slip joint bushing of the jack.

Fig. 4 shows a modified form of back check.

Fig. 5 shows a modified form of removable connection between the jack and wippen.

In the-drawing there is showna unit of a piano action including an action rail it), frame structure ii, and upper rail i2, all associated and arranged in the usual manner with respect to the piano strings 53 mounted on the back plate M.

The action herein shown by way of illustration is of the character generally employed in upright pianos, and embodies a hammer l5 associated with a string damper l5 and wippen [1. The wippen is fulcrumed at l8 on the rail III by a supporting flange Ili Associated with the wippen there is-provided a. piano key is supported for action upon the keyboard 28. The actuating end of said key is provided with the usual capstan screw 2! engaging a cushionin felt 2| on the Wipp n l Secured to the wippen and upstanding therefrom is a jack supportin flange 22 which is bifurcated and provided with a pivot pin 3| for removably receiving and pivotally supporting the jack.

The jack, instead of being a rigid stick, is knuckled for flexibility and comprises a jack member 23 having its upper end pivotally connected at 24 to a link 25, the other end of which is pivotally connected at 25 to the underside of the hammer butt 2?. ihe jack is provided with a heel portion 28 engageable with the adjustable contact button 29 upon actuation of the piano key. As shown in Fig. 3, the lower end of the jack is adapted to slip between the bifurcated portion of the flange 22 and i provided with a slip joint bushing 30 having a facing thereon arranged to spring over the pivot pin 3| carried by the flange. Thus the jack may be readily slipped on and off of the wippen. In the usual manner, between the heel 28 on the jack and the wippen there is a compression spring 32.

Extending rearwardly and downwardly from the hammer butt there is provided a wire back check 33 positioned for engagement by a leather covered cushion 34 secured to the adjacent surface of the jack. The back check 33 may be preferably made of wire with one end secured in the hammer butt, the other end curved and flattened at 33 for engagement by the cushion. Thus the back check is adjustable by bending to adjust the escapement. In the modified form shown in Fig. 4 the wire back check I33 is similarly mounted upon the butt 21, its free end terminating in a wooden head I35 carrying the cushion 134 thereon for direct engagement by the wippen.

In operation it is to be noted that the flexible link jack is at all times during actuation of the piano key permanently connected to the hammer butt as well as to the wippen. Therefore, at no time does the butt end of the jack slide ofi to one side of the butt knuckle to provide escapement of the hammer from the string as in the standard practice. It is, therefore, not necessary for the key to be completely released to permit the jack to move back into actuating position, since its pivotal connection 25 remains permanently in fixed position. However, by reason of its flexibility due ot the link 25 it permits of the required escapement of the hammer from the string. Upon the key being partially released after striking, instead of fully released as heretofore, the jack spring flexes or pivots the jack back to normal striking position sufliciently to permit the key to strike a subsequent blow Without the key returning to the normal at rest position. Thus the jack need not return to its overcenter position from that shown in Fig. 2 to that of Fig. l in order to actuate the hammer. It need only approach its straightened out position which it will do upon the key being partially released. 111 such position as indicated by the dotted line in Fig. 2 and with the key only partially released, further actuation of the key will impress the necessary force on the hammer to strike the string through the jack. In this manner and by reason of the flexibl jack anchored at one end to the hammer butt, double repetition as in a grand piano action is made possible.

This construction also permits of convenient adjustment by reason of the relation of the wire back check to the butt and flexible jack. It will be noted that the back check may be slightly bent for obtaining proper adjustment to thereby avoid the usual regulation as well as permit elimination of the bridle tape and bridle tape wire. Wherein the flexibility of the jack is attained as shown herein by the pivotal link arrangement and with its permanent connection to the hammer butt, the usual sliding friction therewith is avoided, the usual butt knuckle eliminated and blocking thereof either by packing of the front rail key punching or by compression of the back check cushion is avoided.

It may be further noted that inasmuch as the jack is more or less permanently connected to the butt as distinguished from the usual sliding engagement therewith, it is of advantage to removably connect it at its lower end to the wippen as indicated in Fig. 3. Thus the slip joint bushing 30 may be readily slipped on and off of the pivot 3| on the wippen flange 22, while at the same time being pivotally retained thereon under tension exerted on the bifurcated portion by the clamping screw 35,

In the modified form of Fig. 5, the flange I22 which pivotally connects the jack 23 to the wippen H1, is removably secured to the wippen by the screw I24. Thus in this modification the jack is permanently pivoted to the flange, but still is removable from the wippen.

The invention claimed is:

1. In a piano having actuating keys, a hammer action mounted to strike a piano string including a hammer butt, a wippen operable by one of said keys, a jack connected at each end to said wippen and hammer butt respectively, said jack being flexed upon actuation by said key to provide escapement of the hammer from said string, and a back check having a bendable support secured to said butt extending downwardly into position to be engaged by said jack for limiting its flexing movement, said support being bendable to effect adjustment thereof.

2. In a piano having actuating keys, a hammer action mounted to strike a piano string including a hammer butt, a wippen mounted below said butt operable by one of said keys, and a. jack pivotally mounted on said wippen having a link connection with said butt pivoted thereto, said link connection permitting said jack to be flexed upon actuation by said key to provide escapement of the hammer from said string, and a wire back check secured to said butt and bendable into adjusted position for engagement by said jack to limit its movement and permit escapement adjustment of the hammer.

FRANCIS C. SOCIN.

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

UNITED STATES PATENTS Number Name Date 326,576 Menges Sept. 22, 1885 2,260,310 Gould Oct. 28, 1941 172,621 Frickinger Jan. 25, 1876 472,109 Dimick Apr, 5, 1892 1,090,192 Blessing Mar. 17, 1914

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