US2456321A - Piano dampening mechanism - Google Patents

Description

De. 14, 194s.

H. B. RHODES- PIANO DAMPENING MECHANISM i j l fjrwe/wtofr/ l HaroldBJZlwdes Filed NOV. 1 9, 1947 Patented Dec. 14, 1948 UNITED TAT ES PATENT O F F lLC E :PIANO DAMPENING' MECHANISM Harold 'B'; Rhodes, Los Angeles, Calif.

Application .November 19, 1947,.Serial.N0. 786,951

11 Claims. 41 *They .present inventioni relates to pianos 1 and, primarily, to pianosoffminiature size. The invention isa modiicationgof and improvement upon the type of piano construction shown in mycovpending.applicationfor patent, Serial No. 726,004, `and reference .is made `to thatapplication rfor a f full'wand completeudisclosureof 4certain 4features `of thi-)invention` and ofthe type of musical instru- ;mentwith which the present improvements may be* employed.

rilieinvention, howevenfis not conned in its use to pianos of this type, since .thepiano action and vibration dampeningmeans described below may beused to great yadvantage with conventional, full-sizeipianos.

The primaryfobject of the:invention is to provide improved and simplified-.vibration controlling 1 andtdampening devices-,tothe end ithatthe action will Abe* substantiallyfthe same as the action in full size, conventional pianos.

s Another object iste-.provide an improved-piano l action anddampeningfmachanism forusein conventional pianos having @conventionalpiano harps andsounding boards.

' Thev invention provides an exceedingly simple dampeningA action, in whichgthe `dampening -devi ses` are moved to, an.` inoperative .positionwhen the corresponding keys areI struck,\and.a-re held inthat position as long as `thekeys arer depressed, .fbutwhich areimmediately. brought into vibration wdampeningposition Whenfthe keys are, released. l.Hencathe toneduration offindividual notesmay `beV controlled, within' the.. usual limits, ,byr the .length of `ltime .that .the individual: keys are held down, asin thecase with large, expensive, con.v

:'ventional pianos.

. Anotheraobject ogthe invention ais y.to provide kan `vv improved sustainingaction control, similar to the sustaining pedal of standard-pianos. To this end, the invention provides simple, inexpensive, aand enicientzmeans for rendering all of the vibrazftion dampening devcesinoperative simultaneously, .so :that -the'vibrationsxof all keys struckv will ...continue .until they; ,i normally 1 die down or until ,fthe dampening: devices i are; again simutaneously I.broughtyintofoperation, rbymanual` or pedalv conxtrol.

Another obje-:t of theinventionis to provide `.wanfimprovedf hammer supporting structure, which issimplen cheaper andbetter `suited for thede- :.=sired .purposes :thanl corresponding structures '1., heretofore known.

'f/Other. andfurther objects andadvantages of the invention will be apparent from a considera- -tion of the following description of a-preferred em- .enlargedscala taken on line 4 4 of Figure l, and

Figure 5 is a fragmentary perspective View of an improved .hammer supporting' comb.

The piano comprises a unitary, molded, plastic,

. resonant case I0 of fiber glass or the like, which serves as the piano sounding board, as explained .in my application identified above. The case l0 ...has a topwall I I, front, and rear walls l2 and I3,

andintegral side walls, one of `which is shown at I4, allconnected by rounded corners and secured toa base casting'l. -Thefoase has sideflanges I6 ,andafront section Il, to which the forwardly exttending, open,shelflikev portion I8 of the case is secured. Aiinishing and strengthening strip I9 may extendalong the lower edge of vthe front Wall I 2,. adj acent the keyboard.

The base I5 includes a transversely extending ulerumed -rail fork thewhitekeys 2l,v and the rblack keysv EZWhich-project forwardly and rearwardly from the rail. Projecting upwardly from rfulcrums `for the keys. .keys are provided with guide slots 36, embracing carried bythe .front section `I'I of the'base. 40]

`tiened pins 32.and 24 are .associated with the black .keys..22, while the forwardly ypositioned pins 3I the ,rail are two series of pins 23,. 24, extending through apertures 25 in the-bottoms of the keys .a-nddisposedsnugly within longitudinal guiding l slots 26. Felt strips 21 `and 28, disposed between thai-ail.. wand the undersurfaces of the keys,

surround thepins 23 and 24 and serve as cushion At their forward ends the twoseries ofupwardly projectngpins 3l and 32 It willbe. understood that themore rearwardly. posiand 25 support. and guide the white keys 2 I. The

., .and limit the upward movement of the keys.

The .rear endsof thekeysare supported, when at rest,upon a .felt strip-38, Vsecured to the rear -portion I5 of the Aframeand their upp-er surfaces carryfelt pieces 39, underlying the hammers 40.

- Thehammers have curved undersurfaces 4 I, en-

rgaging the rear ends of thev keys with a rolling,

accelerated movementfcontact, as explained in the above-mentioned application. ,In 4the present oase,

the keys are preferably made of molded, plastic material and are of simple bar form. They are pivoted adjacent their rear ends to a rod 42 carried in apertures formed in the tines 43 of a comb structure 44, the tines serving to space the hammers apart, corresponding to the spacing of the keys and the Vibratory rods hereinafter described.

The comb may be constructed by using two pieces of wood, 45 and 46, such as two s/8 plywood strips, cutting grooves 41, 48 in their surfaces, inserting a continuous felt channel in the groove so formed, securing the sheets together, for instance by a thermo-setting resinous adhesive along the meeting faces 45, and then cutting the slots 50 with a gang saw or the like, leaving a plurality of individual felt bushings 5i in the laterally projecting, vertically disposed tines 43. Experience has shown that a wooden comb, constructed in this manner, particularly when moisture-proof plywood is used, is very efficient, will not warp, and is particularly indestructible in use. The felt bushings in the individual tines, produced in this manner, are quite inexpensive and provide an admirable support for the rod 42 upon which the individual hammers are pivoted. A tone bar 55, preferably constructed of cast iron has a Flange 56, secured to the undersurface of the top wall Il of the resonant case by bolts 51, with collars 58 interposed between the case and the fia-nge. The collars may be integral with the flange 56 of separate elements, as desired, and the bolt heads may extend entirely through apertures in the case or may be disposed in molded bosses, as described in the above mentioned application.

A plurality of steel spikes or vibratory rods 6l), having the physical structure described in detail in the above mentioned application, are secured at their forward ends 6| to the tone bar 55, by

a clamping bar 62 and suitable screws 63. The

rods, of varying length, vibrate at predetermined frequencies and produce the notes of the scale. Each rod is vertically aligned with one of the hammers 4u so that the striking cushion of hard felt 40a carried thereby will engage the reduced neck 64 thereof.

Secured to the rear surface 65 of the back bar of the comb 44 is a sheet of spring metal BB, having a slotted upper portion providing a piurality of upwardly and forwardly projecting spring .fingers 61, each of which is aligned with one of the vibratory rods 60, and each of which carries, adjacent its free end, a felt block or cushion 68, having a V-shaped groove 69 in its upper surface, positioned to engage the aligned rod 6D, as shown in Figures l and 4, to dampen the vibrations set up in the rod. Each spring finger is slotted as at 10, to provide an upwardly projecting prong or barb 1I, constituting a securing means for the upper end of a flexible strap 12, the lower end of which is wrapped partially around and secured to the rear end face 40h of the associated hammer 4U. Hence, it will be apparent that, when the key is oscillated in a clockwise direction, so that the forward end rises to strike a note, the rear end face moves downwardly, thereby pulling the associated spring finger downwardly and withdrawing the cushion 68 from the associated rod 6I), and permitting the rod to vibrate and hold the note, until the key is released. When the key returns to its normal position shown in full lines in Figure 1, the spring finger rises, carrying the cushion block B8 into Contact with the rod, thereby dampening the vibrations.

The sheet 66 and the spring. fingers 61 are preferably made from aluminum or aluminum alloy of the proper thickness and hardness to impart to the ngers just enough tension to press the cushion members 68 against the rod $0 with sufficient firmness to promptly dampen vibrations therein, yet to apply minimum strain or resistance to movement of the hammers 4D and keys 21.4 No more force than is required to dampen the vibreI tions in the rods should be applied to the cushions by the spring fingers. The strap connections bc-i tween the spring fingers and the hammers perl' form the additional function of urging the ham-i' mers downwardly so as to maintain a, positivecontact between the bottoms of the hammers'- and the keys at all times, except after the rear'V ends of the keys have reached their upper limitol i movement and the hammers continue their travnlupwardly, under the momentum imparted theretGf by the keys, to strike the bars. The spring nngers and the strap connections with the hammers also hasten the return of the hammers to their positions in contact with the keys. Thus, this structure very materially speeds up the repeating action.

It will be understood that, as soon as a key is depressed and the hammer slightly raised, the associated spring finger and cushion are depressed and the rod is free to vibrate. This condition remains, as long as the key is heldA depressed, but the dampening action occurs immediately, when the key is released and the key and hammer have assumed their normal positions.

It has been found advantageous to employ steel,

rods as the vibrating elements, instead or ther beryllium-copper alloy previously suggested, al though the invention is not limited to specifici materials in this connection.

Pivotally secured in bosses 15 formed in thef side walls of the casing, or supported 'from sluit` able pedestals mounted on the base, is rod' 16H,.- extending transversely above the spring finger 6.1.

The rod carries a forwardly projecting member. in the form of a lvane or wing 18, having a felt strip 19 on its forward edge. A crank arm 8D, fast on the shaft 1G may have its free end connected to a Bowden wire 8l, comprising a flexible tube 82, connected at one end to the base l5 and at the other to a bracket B3 for a foot pedal 84, the free end of which is connected to the other end of wire 8l, Of course, any other actuating mechanism could be employed and the one shown is simply typical of many alternatives. When the rod 1S is oscillated, by whatever means employed, so as to depress the forward edge of the vane or wing 13, the latter depresses all of the spring fingers 51 and moves all of the cushion blocks 68 out of contact with the vibratory rods $0, thus giving a sustaining action, the equivalent to the sustaining pedal action of a conventional piano.

It will be understood that the piano action and vibration dainpening mechanism described above may be used with conventional pianos, including the usual sounding board, harp and piano strings; that the cushion blocks B8 will normally be pressed into vibration dampening relation with the strings of the harp, and that they will be withdrawn upon movement of the hammers 40 into striking relation to the strings. The sustaining pedal action may be substantially identical as described above, so that all of the springs 61 may be shifted simultaneously, to maintain all the cushions 68 out of contact with the strings for the desired period or time.

The invention is not limited to the specific Vand rearwardl aufrufen f5 details ci construction shownin-the accompanye ing drawings and described above, rbut includes modications vcorn-ingwithin the scope of the appended claims and their equivalents.

I claim: v

l. Ina piano of the type wherein a tone bar havingaplurality of vibratory rods carried'thercby is se'curedto the undersurface of a resonant case, a plurality of piano action assemblies for the reds, each assembly comprising a key pivote'd intermediate its ends and projecting forwardly a vhammer pivoted adjacent its rear end, projecting forwardly and having v-a curved undersurface rung upon the rear `end of'thelr-ey, a spring iinger projecting into proximity to the correspondingrod, acushion carried by the free end ofthe spring and a flexible strap connection between the spring andthe're'ar end ofthe hammer beyond the pivot thereof, whereby, when'v the upward `swinging movement of the forward end oli the hammer commences, said connee'tion moves ldo'wnwardly to withdraw lthe cushion iomthe rod,

'2. :In a piano of the type wherein a'tonelbar is secured to the undersurface of a resonant case, and wherein a plurality of vibratory rods are carried-by the bar, means for creating and controllinglthe vibrations in the rods, comprising a hammer supporting shaft within the case, a plu'- rality of hammers pivotally secured to the -shaft for upward swinging movement to strike the rods, plurality of spring fingers projecting upwardly intofproximity with the rods, a -cushion -elementfcarried by each finger, a key below each hammer forvswinging the same upwardly tostrike the associated rod andtension connection means between the rear, downwardly swinging end'of each hammer and theassoeiated spring finger,

whereby upward swinging movement of the hamp merdepresses` ,the associated spring iinger and withdraws the `cushion from the rod,

3. In a piano ofthe type wherein a tone'bar is secured tothe undersurface of a resonant case, and wherein a vplurality of vibratory rods are carried by the bar, means for creating and controlling the Vibrations in the rods, comprising a hammer supporting comb within the case, a plurality of forwardly projecting hammers pivotally supported by the comb for upward swinging movement to strike the rods, a plurality of spring lingers having their free ends positioned adjacent the rodsVa plurality of cushions carried by the Iingers,a keyvv below each hammer for swinging the same upwardly, and a iiexible strap connection between the rear end of each hammer and the associated spring nger, whereby upward swinging movement of the hammer depresses the spring nger and withdraws the cushion.

Il. In a piano of the type wherein a tone bar is secured to the undersurface of a resonant ease, and wherein a plurality of vibratory rods are carried by the bar, means for creating and controlling the vibrations in the rods, comprising a hammer supporting comb within the case, a plurality of forwardly projecting hammers pivotally supported by the comb for upward swinging movement to strike the rods, a plurality of spring fingers secured to the back of the comb and projecting forwardly with their free ends positioned adjacent the rods, a plurality of cushions carried by the fingers, a key below each hammer for swinging the same upwardly, and ilexible strap connection between the rear end of each hammer and the associated spring nger, whereby upward l6 swingingmovement of the hammer depresses the spring 'ringer and withdraws the cushion.

-5. Iny a piano "of the type wherein a tone bar is secured to 'a resonant case and wherein a plurality of vibratory rods are carried by the bar, means ffor creating, controlling the duration of, and dampening the vibrations in the rods, comprising a wooden comb supported within the case, a shaft extending through aligned apertures in the tines 'of thecomb, felt bushings in the apertures embracing the shaft, a plurality of forwardly projecting-hammers pivoted onthe shaft and spacediapart-by the tines, a plurality of leaf spring yfingers secured to the back of the comb and-.projecting upwardly and forwardlywith their freeends'positioned adjacent the rods, a cushion member carried by each finger below and normally in contact with the adjacent rod, a key below each hammer for swinging the same upwardly to strike the associated rod, and a plurality of flexible strips each having one end connected to one ngerand-the other end connected to the y rear "end vof the associated hammer, whereby upwardswinging'movement of the hammer depresses the associated ringer and withdraws the cushion.

'6. In a piano ofl the type wherein a tone bar is secured toa resonant case and wherein a plurality of vibratory rods are carried by the bar, means for creating, *controlling the duration of, and dampening the vibrations in the rods, com prising a wooden comb supported within the case, al shaft extending through aligned apertures in the tines'of the comb, felt bushings in theapertures embracing the shaft, a plurality of forwardly projecting hammers pivoted on the shaft andfspaced apartby the tines, a plurality of leaf spring nngers secured to the lback of the comb and projecting upwardly and forwardly with their free ends positioned adjacent the rods, a cushion member carried by each finger below and normally in contact `with the adjacent rod, a key below each hammer forswingingl the same up*- war'dly to strike the associated rod, a plurality of 'exible strips each having one endconnected tofo'ner finger and the lother end connected to the rearfend of the associated hammer, whereby upward swinging movement of the hammer depresses the associated finger and withdraws the cushion, a member extending transversely across and above all of said spring `fingers and means for shifting the member to depress all of the fingersfand to withdraw all-of the' cushions simultaneously'for sustaining pedal action.

7. In a piano of the type wherein a tone bar is secured to the undersurface of a resonant case, and wherein a plurality of Vibratory rods are carried by the bar, means for creating and controlling the vibrations in the rods, comprising a hammer supporting comb within the case, a plurality of forwardly projecting hammers pivotally sup ported by the comb for upward swinging movement to strike the rods, a plurality of spring 1in-- gers having their free ends positioned adjacent the rods, a plurality of cushions carried by the fingers, a key below each hammer for swinging the same upwardly, a flexible strap connection between the rear end of each hammer and the associated spring nger, whereby upward swinging movement of the hammer depresses the spring finger and withdraws the cushion, and means common to all of the spring fingers, shiftable to withdraw all of said cushions simultaneously for sustaining pedal action.

8. In a piano of the type wherein a tone bar is secured to the undersurface of a resonant case, and wherein a plurality of vibratory rods are carried by the bar, means for creating and control ling the vibrations in the rods, comprising a hammer supporting comb within the case, a plurality of forwardly projecting hammers pivotally supported by the comb for upward swinging movement to strike the rods, a plurality of spring ngers having their free ends positioned adjacent the rods, a plurality of cushions carried by the fingers, a key below each hammer for swinging the same upwardly, a flexible strap connection between the rear end of each hammer and the associated spring finger, whereby upward swinging movement of the hammer depresses the spring finger and withdraws the cushion, a member eX- tending transversely across and in proximity to al1 of said fingers and pivoted off-center, and means for swinging the member to flex the springs and to withdraw all of the cushions simultaneously, for sustaining pedal action.

9. A piano comprising a resonant case, a tone bar rmly secured to the undersurface of said case, a plurality of vibratory rods supported by said bar and freely projecting therefrom in a rearward direction, a hammer supporting comb in the case below the rods, a plurality of forwardly projecting hammers pivotally connected adjacent their rear ends to the comb, a sheet of spring metal secured to the rear surface of the comb and having a plurality of forwardly projecting fingers, each aligned with a rod and having a free end positioned therebelow, a plurality of vdampening cushions, one carried by each finger below a rod and having a grooved upper surface for contact with the rod, a plurality of keys below the harnmers for swinging the latter upwardly to strike the rods, and a strap connected to the rear, downwardly movable end of each hammer and to the corresponding finger, to withdraw the cushion when the hammer swings upwardly.

10. A piano comprising a resonant case, a tone bar firmly secured to the undersurface of said case, a plurality of vibratory rods supported by said bar and freely projecting therefrom in a rearward direction, a hammer supporting comb in the case below the rods, a plurality of forwardly projecting hammers pivotally connected adjacent their rear ends to the comb, a sheet of spring metal secured to the rear surface of the comb and having a plurality of forwardly projecting fingers, each aligned with a rod and having a free end positioned therebelow, a plurality of dampening cushions, one carried by each finger below a rod and having a grooved upper surface for contact with the rod, a plurality of keys below the hammers for swinging the latter upwardly to strike the rods, a strap connected to the rear, downwardly movable end of each hammer and to the corresponding finger, to withdraw the cushion when the hammer swings upwardly, a transversely extending vane positioned above all of said fingers and pivoted adjacent one edge. and means for swinging the other edge downwardly to depress all of said fingers and to withdraw all of the cushions, for sustaining pedal action.

11. A piano comprising a resonant case, a tone bar firmly secured to the undersurface of said case, a plurality of vibratory rods supported by said bar and freely projecting therefrom in a rearward direction, a hammer supporting comb in the case below the rods, a plurality of forwardly projecting hammers pivotally connected adjacent their rear ends to the comb, a sheet of spring metal secured to the rear surface of the comb and having a plurality of forwardly projecting fingers, each aligned with a rod and having a free end positioned therebelow, a plurality of dampening cushions, one carried by each finger below a rod and having a grooved upper surface for contact with the rod, a transversely extending fulcrum rail disposed forwardly of the comb, a series of pins projecting upwardly from the rail, a second series of upwardly projecting pins spaced forwardly of the first end aligned therewith, a plurality of keys fulcrumed on said rail and each having a bottom aperture and a communicating, longitudinal guide slot closely embracing one of the first series of pins and another longitudinal guide slot spaced forwardly therefrom and receiving a pin of the other series, the keys having rear ends underlying the hammer, and a plurality of straps, each connected to the rear end of one hammer `and to the corresponding finger, to depress the nger and withdraw the cushion when the forward end of the hammer swings upwardly.

HAROLD B. RHODES.

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

UNITED STATES PATENTS Number Name Datel 1,490,476 Morris Apr. 15, 1924 2,244,332 Finney June 3, 1941

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