US2844984A - Upright piano action - Google Patents

Description

y 1953 4 c. H. DASENBROOK ET AL 2,844,984

UPRIGHT PIANO ACTION Filed July 15, 1953 s Sheets-Sheet 1 Dacenb rack Dc erUov-co July 29, 1958 c. H. DASENBROOK ET AL 2,844,984 UPRICQHT PIANO ACTION 3 Sheets-Sheet 2 Filed July 13, 1953 NVZZIOTO'QJ g im rle-J :DcuSenbr'ock ovrqaq .Dcus nb weer; A7 I Qfl-ITORME c H. DASENBROOK ET AL 2,844,984

July 29," 1958 UPRIGHT PIANO ACTION 3 Sheets-Sheet 5 Filed July 13, 1953 IST/ low Chcurle gtDa-senbr'ook. Ormqy .Dqd brook Cum, w fl msfl United States Patent z,s44-,9s4

UPRIGHT PIANO ACTION Charles H. Dascnbrook and Norman K. Dasenbrook, Rockford, 111., assignors to Wood& Brooks Company,

Buffalo, N. Y., a corporation of New York Application July 13, 1953, Serial No. 367,583

Claims. (Cl. 84--240) This invention relates to the now standardized type of actions. as commonly used in present dayupright pianos. In such actions, the key motion is transmitted to thebutt knuckle of the hammer through an upwardly-extending jack which is pivoted on the whip and retracted out of engagement with the knuckle when a regulating button isencountered. As the key pressure; is relieved, the tip -ofrthe jack often fails to recover beneath the butt. knuckle for a repeat blow.

It hasl'long been recognized that from .a performance standpoint, such upright actions are less satisfactory than theaction used in regular grand pianosparticularlybecause ihereis no means operable during thetinitial release ofxthe key to retard the butt and permit rapid recovery .of the jack beneath the butt for quick repetition of another blow by the hammer.

.The primary object is to overcome the foregoing. defect and'produce an upright action of'standard. construction whichwill, in'all respects, matchhthe: performance sof a grand piano action.

Another object is to increase the speed'ofrecovery 'of the :jack beneath the butt knucklefollowing release of the key whereby to achieve a resulting action compar'able to that produced by the so-calledrepetitionlever in a grand action.

*A further object is toincrease the magnitude-of the spring force acting on the jack to eifect recovery-of the latterwithout at thesame time impairing these-called touch of the action or preventing uniforrn=back checking of the hammer.

Still another object is to achieve the-foregoing object through a simple modification ofthe 'ja'ck'ofa standard upright action, the associated parts remaining'unchanged in construction and operation.

A more detailed object is to form-thejack-in two parts oneacting on the butt knuckle and the'other subjected to the force of a spring, the two parts being 'joined through a lost motion connection by which thespring 'force on the jack is relieved whilethe'jackis being withdrawn from beneath the knuckle in'the' finalpartof-"the key motion.

The invention also resides in the novelconstruction and arrangement of the jack parts to achieve over-all compactness, optimum rapidity of jack recovery, and simplicity of manufacture and assembly.

Other objects and advantages of the. invention will become apparent from. the following detailed description .taken in connection with the accompanying drawings, in which Figure 1 is a fragmentary vertical cross sectional view .of an upright piano action embodyingthe.novelz'featu-res of. the present invention.

Fig. 2 is a fragmentary section taken along the-line Fig. 3 is a plan view of the jack. Fig. -4 is an exploded perspectiver'view of theiijack.

in the art.

. Figs. 5, 6, and 7 are fragmentary views similar to Fig. 1 showing the parts in different positions.

Fig. 8 is a view. similar :to Fig. 1 showing modified form of the invention.

Fig. 9 is a front elevational view of the, jack of the actionvshown in Fig. 8.

While the invention is susceptible of various modifications and alternative constructions, we have shown in the drawings and will herein describe in detail the preferred embodiment. It is to be understood, however, that .we donot intend to limit the inventionby such. disclosure, but aim to cover all modifications and alternative'constructions falling within the spirit and scope of themvention as expressed .in the appended claims.

.In the drawings the invention is; shown incorporated.

in the action for thepresent. day upright :piano'in which the. keys 11 are disposed above the main rail 12 on' which the moving parts of the action are supported. Eachkey is fulcrumed at.13 in the usual way on abalance rail 14 supported by a bed 15. In the releasedposition shown .in Fig. 1, the key rests ona pad 16.

The main rail 12 is secured to metal frame brackets 17 anchored attheir upper ends through the medium of bolts .18 projecting forwardly from the plate on which the strings 19 are mounted and 'tensioned. Pivotally mounted at 20 on aJfiange of the main rail are a series of hammers .21: arranged to be projected against the respective strings by.depres sion' of the corresponding keys. In the released position shown in Fig. 1, the hammer shanks rest against aicushion on the hammer rail 22. The butt 23 of each hammer carries a leather surfaced knuckle 24which is engaged eccentrically of the hammer pivot by the upper end 25 of a substantially straight jack 26 pivoted at 27 on a whip lever 28. The latter is disposed generally horizontally and is fulcrumed near its rear end on a pivot 29 on the rail 12.

The opposite or free end of the whip lever 28 is pivotally connected through a link 31 to the free end of a lever 32 which overlies the rear end portion of the key 11 and isfulcrumed at 33 on a pivot supported by a flange attached to a rail 34. Intermediate its ends, the lever 32 carries a cloth pad 35 which bears downwardly against the head of a capstan screw 36 upstanding from the rearend of the key.

The action also incorporates the usual catcher 38 carriedby the butt 23 and a back check 37 which coacts in a well known manner to catch the hammer during its rebound from the string following withdrawal of the jack from beneath the knuckle in the final part of the key motion. Also included is a string damper 39 on the upper end of the lever 40 which operates in conjunction with a spoon 41 upstanding from the rear end of the whip. 'The cloth covered regulating button 42 by which the jack is withdrawn from engagement with the butt knuckle 24 is carried by the lower end of a screw 43 threading through a horizontal rail 44 supported on horizontal bars 45 projecting forwardly from the main rail 12.

The action thus far described is of standard construction and operates in a manner well understood Generally stated, the present invention contemplates .first urging the jack 26 in beneath'the knuckle 24 under a force somewhat greater'than that employed in standard upright actions thus retarding the butt return sufficiently to enable the jack to quickly reengage the butt knuckle, and secondly substantially freeing the jack of this force at the time of its withdrawal from the knuckle whereby to preserve the light touch of the action and insure uniformity of the hammer rebound following blows of different intensities. Such freeing action is achieved by'forming the jack in two parts joined by a limited lo-st motion connection, one part acting'on the butt knuckle 24 while the force of the jack spring is applied to the other part.

Referring to the preferred form shown in Figs. 1 to 7, the first or main part of the jack comprises a substantially right angular L-shaped lever 50 having long and short arms 51 and 52 and a heel 53 disposed in the bifurcated upper end of a post 54 upstanding from the center of the whip 28. The lengths of the arms 51 and 52 correspond substantially to those of a standard jack. The jack pivot 27 comprises a pin extending through the heel 53 with its opposite ends bushed into the lips of the post. The tip 25 of the arm conforms to the shape of the standard jack and is engageable in the usual way with the knuckle 24.

The second or auxiliary part of the preferred jack is also a similarly shaped and sized L-shaped lever 55 having long and short arms 56 and 57 nesting into the L of the first lever and joined at a heel 58 which is bifurcated as indicated at 59 to straddle the heel 53 whose opposite sides are cut away as shown in Fig. 4. At a point above the fulcrum 27 and somewhat in front of the long arm 51, the lever 55 is fulcrumed on a pin 60 which is supported by the arm 51 with its opposite ends bushed into the bifurcations of the heel 58. The long arm 56 substantially parallels the arm 51 and extends nearly to the tip 25 thereof, the arm 56 carrying a thin felt pad 61 which is adapted to bear against the front face of the tip 25 and limit the swinging of the parts 51 and 56 in one direction.

The juxtaposed short arms 52 and 57 project forwardly and one carries near its free end a pad 62 which, when the pad 61 is pressed against the tip 25 (Fig. 1), is separated from the other short arm by a gap 63 of about .010 of an inch to provide the desired small amount of lost motion between the two levers 50 and 55. Thus, the lever 55 may be swung clockwise relative to the lever 50 to the other limit of the lost motion as shown in Fig. 5, the tip of the long arms then being separated by a gap 64 of about of an inch.

The two levers are constantly urged together in the opposite direction under a resilient force derived from a spring 65 which preferably acts on the upper end of the jack arm 56 so as to gain optimum mechanical advantage in effecting quick recovery of the jack tip 25 beneath the knuckle 24 following release of the depressed key. While the spring may take various forms, it is shown herein as comprising a length of resilient wire having a double turn coil 65 intermediate its ends and one end portion 66 projecting into and anchored firmly in the rail 44. The other and longer end portion which F is slightly bowed projects upwardly cantilever fashion with its slightly curved free end seated in a shallow graphited groove 67 in the front face of the arm 56. During relative swinging of the levers 50 and 55, the spring end slides slightly back and forth in the groove.

In the final part of the upward swinging of the whip as the key is depressed, the regulating button 42 is first engaged by the short arm 57 of the auxiliary jack element 55 and operates first to take up the lost motion between the two levers and relieve the spring force on the jack proper as shown in Fig. 5. Then, the tip 25 of the jack is withdrawn from beneath the knuckle 24 as the rebounding hammer is back checked in the usual way as shown in phantom in Fig. 6. Such relative movement between the jack parts is preferably effected by disposing the button 42 at the proper height above the outer end of the short arm 57, the jack withdrawing force being, in this instance, transmitted to the short arm 52 of the main jack lever 50 through the pad 61 after the lost motion 63 has been taken up. It will be observed that the main jack fulcrum 27, the point 68 of initial contact between the arm 57 and the button 42, and the auxiliary fulcrum 69 constitute the corners of a shallow triangle whose apex is at the fulcrum 60. By virtue of this relation, the force of the spring 65,

while the arm 57 is engaging the regulating button 42, is exerted to a very slight degree on the main jack lever 50 in a direction to urge the tip 25 toward the butt knuckle. This insures that the main jack tip 25 will continue to remain in engagement with the butt knuckle until the gap 63 is closed and the regulating button 42 becomes effective on both of the jack members as the depression of the key is completed.

The action constructed as above described operates as follows assuming that the whip moves through a range a (Fig. 6) in response to full depression of the key, that the parts are in the released position shown in Fig. l, and that the back check 37 is adjusted to engage the catcher 38 after rebounding of the hammer 21 somewhat beyond the vertical as shown in phantom in Fig. 6. After the key has been depressed and moved the whip 28 through the major part of its range, the tip of the auxiliary jack arm 57 will encounter the regulating button 42 and in the ensuing short movement of the whip to the position shown in Fig. 5, the lost motion 63 is taken up and the arm 56 swung away from the jack tip 25. Substantially the entire force of the spring is withdrawn from the main jack lever 50, and the latter is relatively free. Its tip 25 is retracted in the remaining movement of the whip to the upper limit position shown in Fig. 6 by the time that the hammer strikes the string 19 and starts to rebound.

Since the main part of the force of the spring 65 is now exerted only on the auxiliary jack lever 55, little resistance is offered by the jack to interfere with rebounding of the hammer. As a result, the latter, even in response to relatively light blows on the key, always rebounds to substantially the same position and is caught by the back check as shown in phantom in Fig. 6. The checking action is thus substantially uniform irrespective of the rapidity or intensity of the key motion.

In spite of the freedom of the jack lever 50 due to its lost motion connection with the spring actuated auxiliary lever 55, the full spring force is available immediately in response to a very slight release of the key so as to insure quick and complete recovery of the jack tip beneath the knuckle preparatory to a quick repetition of a blow by the same hammer. In the initial part b (Fig. 7) of the downward movement of the whip, the tips of the jack lever arms 51 and 56 come into full contact as shown in Fig. 7 so that the spring force is transmitted directly to the tip 25 and thus is utilized to optimum mechanical advantage in forcing the jack back beneath the knuckle 24 preparatory to striking another blow on the strings.

It will be observed that with the spring acting on the tip 25 of the jack instead of on the short arm 52 as in standard upright actions, a substantially greater force is available to move the tip in beneath the knuckle 24. As a result, the jack recovers quickly in response to the initial release of the key irrespective of the character of the previous blow so that the action is equally responsive to light and heavy blows irrespective of whether these are sustained or momentary.

The use of the increased spring force to effect such rapid recovery is made possible by the novel manner of reducing the spring force on the jack at other times when a heavy force would be detrimental. Thus, by making the jack in two parts and arranging for their separation in the final part of the key motion, the spring is ineffectual at the time of withdrawal of the jack and continues to be held inactive during rebounding of the hammer and back checking thereof. Consequently, the so-called touch of the action is not impaired and the hammer rebounds properly so as to be back checked in the same position for all kinds of blows. The all around performance of the action is substantially the equal of a standard grand piano action.

Figs. 8 and 9 shows a modification of the jack 26 in which the main and auxiliary levers 50 and 55 are both mounted on the fulcrum pin 27 and the lost motion between the two levers is achieved by different shaping of the short arms 52 and 57 which are disposed side by side instead of one above the other as in the preferred construction first described. To this end, the short arms of the main and auxiliary jacks are offset in opposite directions from the center line of the long arms as shown in Fig. 9 and are narrowed so that they may be disposed side by side within the space allowable with the ends 68 and 69 adapted for engagement with the button 42. The end 68 of the auxiliary arm 57 is, in the released position of the parts (Fig. 8), disposed above the end 69 of the arm 52 by an amount corresponding to the width of the gap 63 thereby providing for the same amount of relative motion between the jack parts as in the preferred construction first described.

The operation of the modified construction is the same as described above. That is to say, in the final part of the upward movement of the whip 28, the tip 68 first engages the button 42 thus causing the tip of the auxiliary jack lever to be separated from the main jack tip 25. Then, as the key motion is completed, the tip 69 encounters the button 42 causing the jack to be withdrawn from beneath the knuckle 24. Finally, as the pressure on the key is released and the whip permitted to fall, there is no lost motion between the jack parts and the spring 65 is effective to force the jack 25 back beneath the knuckle.

We claim as our invention:

1. In an upright piano action, the combination of, a key actuated whip, a pivoted hammer, an L-shaped jack lever pivoted at its heel on said whip and engageable at its tip with the butt knuckle of said hammer, a similar L-shaped lever disposed above and nested in said jack and fulcrumed on the jack adjacent the jack pivot to swing relative to the latter between one position in which the tips of the long arms of the levers engage and a second position in which the short legs of the levers engage each other, a spring continuously acting on said second lever to take up the lost motion between the levers in a direction to urge the tip of the jack lever toward said butt knuckle, and stationary means supporting said spring.

2. In an upright piano action, the combination of, a key actuated whip, a pivoted hammer, an L-shaped jack lever pivoted at its heel on said whip and engageable at its tip with the butt knuckle of said hammer, a similar L-shaped lever disposed above and nested in said jack and fulcrumed on the jack adjacent the jack pivot to swing relative to the latter between one position in which the tips of the long arms of the levers engage and a second position in which the short legs of the levers engage each other, and a spring continuously acting on said second lever to take up the lost motion between the levers in a direction to urge the tip of the jack lever toward said butt knuckle, stationary means supporting said spring, said spring having an elongated arm extending outwardly and along the long leg of said second lever and bearing against the latter near the free end thereof.

3. In an upright piano action, the combination of, an upright hammer shank pivoted at its lower end and having adjacent the pivot a downwardly facing butt knuckle, a whip lever disposed below said pivot and swingable upwardly in response to depression of a key, a jack engageable at its upper end with said knuckle and fulcrumed on said whip lever to move vertically therewith and to swing horizontally into and out of engagement with said knuckle, a downwardly facing regulating button, a member continuously disengaged from said knuckle and hammerand engageable with said button, a spring acting on said member to urge the latter toward said button, stationary means supporting said spring, a stop on said jack limiting the movement of said member by said spring, and means providing lost motion between said member and jack and mounting the member for upward movement with said jack and lever until said member engages said button and is blocked thereby against further movement as permitted by said lost motion, said last mentioned means providing for swinging of said member about an axis paralleling the fulcrum of said whip lever and movable bodily therewith.

4. In an upright piano action, the combination of, a jack comprising main and auxiliary L-shaped levers with long and short legs disposed alongside each other and adapted for limited swinging of said long legs toward and away from each other, a key actuated whip pivotally supporting said levers, a hammer having a butt knuckle engageable with the tip of the long leg of said main lever, a spring hearing at one end against the tip of the long leg of said auxiliary lever and acting to urge the latter leg toward the main lever to first take up the lost motion between the levers and then move the tip of the main lever in beneath said butt knuckle, and means stationarily supporting the other end of said spring.

5. In an upright piano action, the combination of, a whip, a hammer having a butt knuckle, an L-shaped jack lever coacting with said knuckle and having a heel fulcrumed on said whip, an auxiliary L-shaped lever fulcrumed on said first lever adjacent the fulcrum thereof and nested in the first lever with the long legs of the levers lying adjacent and adapted for limited swinging toward and away from each other, a spring, and means stationarily anchoring the spring at one end, said spring acting at its other end on said auxiliary lever in a direction to swing said long legs first toward and against each other and then urge the first lever in beneath said knuckle.

References Cited in the file of this patent UNITED STATES PATENTS 152,912 Moeller July 14, 1874 827,952 Battalia Aug. 7, 1906 854,058 Sauter May 21, 1907 2,468,132 Stein Apr. 26, 1949 2,469,308 Montoya May 3, 1949 FOREIGN PATENTS 84,484 Germany Dec. 13, 1895 86,385 Germany July 27, 1896 143,814 Germany Aug. 28, 1903

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