US2634648A - Piano key action - Google Patents

Description

April 14, 1953 IN VEN TOR.

c. F. s rrH PIANO KEY ACTION Filed April 14, 1951 Cfiazles E 5 1771% Patented Apr. 14, 1953 UNITED STATES PATENT PIANO KEY ACTION Charles F. Smith, Forest Park, Ill.

Application April 14, 1951, Serial No. 221,106

1 Claim. 1

This invention relates to piano key actions and discloses a compact type of piano action, particularly well suited to spinet pianos or pianos of the drop action type, but equally adaptable to the smaller types of grand pianos or to any piano construction wherein space available for the key actions is limited.

It is believed to be a recognized fact that the key actions presently utilized by piano makers in their spinets and other compact types of pianos is inferior to the actions employed in a concert grand piano, for example. The reason for this state of facts is that, in seeking to design actions of such compact dimensions as to be accommodated within available space limits, important sacrifices as to features affecting the qualities of touch and freedom of action must ordinarily be made. It has been stated by a prominent piano manufacturer that to incorporate a concert quality key action in a small grand would result in a freakish looking piano in which the distance out to the front of the keyboard would be at least one-third of the length of the piano. Obviously, such a construction is undesirable. Yet, a high quality action is obviously desirable, even in the smaller types of pianos.

It is therefore the primary object of the present invention to provide a unique piano key action of physical dimensions suitable for use in drop action pianos, spinets and small grands, yet so designed as to avoid sacrifice of any of the desirable qualities of touch, freedom of action or ease of manipulation characteristic of concert type instruments.

depress a given key is as uniform as possible at all points on the exposed area of the key. This is in sharp contrast to certain commercially manufactured drop action keyboards, for example, wherein the force required at the inner end of the key (that is, at the point adjacent the fall board or key strip) may be two or three times the force required at the outer end of th key.

Another specific object of the invention is to provide a key action wherein both the pitch of the keys and the dip thereof will correspond to that of concert type instruments. This also is in contrast to the present practice in the actions of smaller pianos, in most of which the keys are pivoted so close to the exposed portions that they must be positioned with a very perceptible upward pitch in order to provide the desired degree of dip.

This involves several aspects. One specific object of the invention is to provide a key action wherein the force required to Obviously, the deviations from a concert type action indicated above give the smaller instruments a markedly different feel which is very disturbing to an artist accustomed to using a larger instrument, and it is accordingly desirable to provide the smaller pianos with key actions having the same characteristics of pitch, dip and touch as the concert type instruments, but not requiring the same space. Also, to be acceptable, these defects must be overcome and the desirable features achieved without rendering the action slow, sluggish or heavy. The piano must be capable of free key action, easy response, and at the same time of such design as to be economically feasible.

The foregoing objects are accomplished in the present invention by a unique key action so designed as to achieve the requisite degree of tech nical perfection in combination with the ham- FIG mer actions of either upright types of pianos or grands, with the parts of the key action so proportioned as to be housed in a quit limited space.

The single figure shows the invention in its environment.

In the form of the invention here illustrated, the novel structures disclosed and claimed herein are illustrated as they would be employed in a drop type action for an upright type piano. The

hammer action assembly I0 is mounted on an action bracket H and is operatively connected to the key action assembly l2 by a lifter wire 13 which extends from a whip lifter I4 to a lifter dowel It at the upper end of the wire. The hammer action l0 may be of conventional construction with the whippen l5 pivoted, to the whip flange 11 by a pin 18 and pivoted to the whip lifter M by the pin [9, so that upward movement of the wire 13 will raise the fly jack flange 2! and move the fly jack 22 upwardly against the leather surface 23 of the butt 24, thus swinging the hammer 25 inwardly against the strings 26. As illustrated, the action also includes a back check 21 and catcher 28 and is provided with a damper 29 as is conventional practice in the piano art.

The novelty of the present invention resides in the unique construction of the key action 12, which includes a multiplicity of key balance levers 30, each having its inner end 3| operatively connected to one of the lifter wires I3, with a relatively long inner arm 33 adapted to actuate the lifter wire, and with a shorter arm 34 extending forwardly. The balance arms 30 are each mounted for independent pivotal movement on a vertical balance pin 32, and are provided with a guide pin 36 adjacent their inner end 3|, so that while the arm are free to move up and down in pivotal action about the balance pins 32, they are nevertheless restrained from lateral movement by the guide pins 36.

The outermost, or forward, arm 34 of each of the balance arms 38 has a recess 3'! in its upper surface, with a dowel 38 in the recess and extending upwardly therefrom. The upper end of each of these dowels is received in a recess 39 on the underside of one of the key levers, generally designated as at. Each key lever 46 consists of an exposed key portion 4| forwardly of the molding 32 of the fall board, with an inner lever extension 43 of a length somewhat greater than the length of the exposed portion ii of the key extending inwardly to a point adjacent to and above the inner ends 35 of the balance arms 30, where each key lever is pivoted on a pivot pin 45 mounted in the rail 46 and extending into a recess 44 in the lever. Thus, the rail 45 supports the inner end of each of the key lever extensions 83, while the outer ends of the key levers are supported solelyby the dowels 38, resting on the inner ends of the balance arms 38. The individual keys are each provided with front pins 55 located just inside of the key slip 52 to function as guides, permitting freedom of movementv of the keys in a vertical direction, but preventing lateral movement thereof.

The black keys (sharps) 438 are of thesame construction as the keys just described, except that the front pins thereof are located further inwardly from the key slip 52. The black keys have their inward extensions pivoted on the pins 55 in the manner just described, however, and are each provided with a dowel 38 serving to actuate a balance lever 35 in the same manner as practiced in connection withthe White keys. The balance levers utilized for the black keys may, however, have their balance pins 54 located sligh*- ly rearwardly of the position of the balance pins 32. V V

From the above it will be seen that although the key action disclosed here is so designed as to require comparatively little space in the piano, yet it nevertheless succeeds in avoiding the faults ordinarily present in compact or. drop type actions. A first essential in this regard is that the radius over which the keys dip be. asgreat-as possible, so that thetouch or force required to depress the key will be fairly uniform at all points on the exposed key surface. This is accomplished in the present teaching by providing the pivotal point of the key lever at the extreme inner end thereof, so that the pivot is at a point farremote from all of the exposed portions of the key. This placement of the pivot of the key lever also results in a key action wherein the keys do not tilt to an unduly large degree, but remain fairly uniform in pitch while at rest or when-depressed. The key motion is nevertheless transmitted to the hammer action through quick acting and efiicient operating connections. The balance arm as here disclosed is comparatively short and need not beof any considerable mass, yet the action is so arranged that the vertical movement of the inner end of the balance arm may 4 be substantially equal to the dip of the keys, so that the motion transmitted to the whippen of the hammer action is entirely adequate to actuate the hammer.

The keys are returned to normal raised position by force transmitted from the hammer action without the necessity of auxiliary weights or springs, and, as a consequence, the entire action is free to respond to a relatively light touch and is capable of quick action and almost instantaneous recovery after the key is struck.

A further advantage of the action disclosed herein resides in the fact that the balance arms need not be in precise alignment under the keys by which they are operated. Thus, in a piano having two or three action frames, for example, the keys may be retained in absolute parallelism throughout, but the angular position of the balance arms varied as required to establish operating connections from the balance arms to the Whi-ppens of the several hammer action assemblies. f I Having thus described my invention, what I claim as new and desire to protect by United tates Letters Patent is:

In a piano, the combination, with a hammer action including a multiplicity of hammers each actuated by a whippen and fly jack, of a corresponding multiplicity of key actions adapted to individually actuate said hammers; each of said key actions including a balance arm operatively connected to one of said hammers through its.

corresponding whippen and fly jack, said balance arm having a vertical aperture at an intermediate point of its length and being pivotally mount ed on a fixed vertical balance pin extending through said aperture, the balance arm having a relatively long operating portion extending rearwardly from the balance pin, with a shorter operated portion extending forwardly therefrom; together with a key lever for each of said balance arms, each key lever havin an exposed. key portion and an inner lever extension,- said lever extension being pivoted at the extreme inner end thereof and at a point adjacent and above the operating portion of the balance arm, with the pivot thereof spaced from the inner end of the exposed portion of the key a distance at least equal to the length of the exposed key surface thereof;

with anoperating connection between the key lever and the balance arm at a point substantially equidistant from the opposite ends of the key lever and on the forward operated end of said balance arm, the operative connection comprising a dowel extending between oppositely disposed recesses in the upper surface of the balance arm and the lower surface of the key lever.

CHARLES F. SMITH.

References Cited in the file f this patent UNITED STATES PATENTS Sweden Dec. 27 1934

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