US2431350A

US2431350A - Piano

Info

Publication number: US2431350A
Application number: US530292A
Authority: US
Inventors: Stein Charles Frederick
Original assignee: PRATT READ AND CO Inc
Current assignee: PRATT READ AND CO Inc
Priority date: 1944-04-10
Filing date: 1944-04-10
Publication date: 1947-11-25
Anticipated expiration: 1964-11-25

Description

Nov. 25, 1947.

C. F. STEIN PIANO 3 Sheets-Sheet 1 IIYVEN-TOR. reae TLC/15 621 201 Ciao] I NOV. I C ;F sTElN I PIANO Filed April 10, 1944 s Sheets-Sheet 2 Uzarleaflec zierfi m C. F. STEIN Nov. 25, 1947.

PIANO Fild April 10, 1944 3 Sheets-Sheet 5 Z AKM Patented Nov. 25, 1947 OFFICE PIANO Charles Frederick Stein, Chicago, Ill., assignor to Pratt, Read & 00., Inc., Ivoryton, Conn., a corporation of Connecticut Application April 10, 1944, Serial No. 530,292

9 Claims. (Cl. 84--176) My invention relates in general to pianos, and more in particular to a piano structure, which not only lends itself to high speed production line assembly, but also provides an improved quality piano construction in which the parts are uniform and are assembled into a precision instrument so that all pianos utilizing the invention can be standard and of a high quality.

The production of pianos over the long preceding history of this art has been somewhat of a "custom-built operation. Different practices were introduced to speed up piano manufacture, but it still remained an operation wherein each piano was generally slightly or considerably different as a result ofhandfitting certain portions at least, and generally was characteristic of the individuals working upon it. Except in the most expensive pianos, there was often marked lack of uniformity among pianos so far as playing quality, stability of tuning, and the like was concerned. Those efforts which have been made to provide a piano construction and methods lending themselves to high speed uniform production have been notably unsuccessful in the past. Furthermore, no successful construction has been developed wherein the operating or playable portion of a piano could be manufactured entirely independently of the case or housing unit, and consequently, in some part of the complete manufacturing process prior to final assembly and adjustment of the operating parts, it was found necessary to assemble at least a portion of the case to such parts. Thereafter, throughout the remaining manufacturing steps, that portion of the case, or all of the case, as it might be, was subject to marring, scratching and the many other injuries common to any case or cabinet construction having a high finish.

In addition, in the past, the necessity for assembling the case and the operating parts together during manufacture in order to have a commercially successful piano, has complicated shipping because of the bulk of the completed product.

It is an object of my invention to provide an improved piano both in construction and playing qualities.

Another object of my invention is to provide a piano mechanism and case in which the parts are uniform and of such a construction that they may be assembled together rapidly, and yet in-a precision-like fashion.

A further object of my invention is to provide a piano construction with one preassembled unit which comprises all of the operating parts and.

is entirely self-supporting and playable, but is adapted for connection with the second unit comprising the case or cabinet which is used solely to style the piano. A still further object is to provide an operating unit for a piano which may be regulated, played, and is complete in every way except for the outer styling which may be provided by any one of a number of different case structures and designs. It is also an object of my invention to provide a piano mechanism which lends itself to a high speed assembly line method of manufacture with out sacrificing tone, stability of tuning, uniform key and action operation, or any of the factors which are necessary in an acceptable piano. In fact, one of the features of my invention is that it provides a piano construction in which every finished piano has a quality comparable with, or better than, the quality of pianos made under laborious custom-built methods. 7

Another feature of my invention is that it pro vides a piano operating unit including preassembled portions which are readily assembled together for final regulation and adjustment in a factory, but which are then readily disassembled into portions for easy handling, packing, and finally, shipment to any desired point. Not only is the shipment simplified as a result of the construction of such portions, but at the point of destination the portions may again be assembled by unskilled help and readily connected to a case or housing. Consequently, after the initial manufacture of the operating unit there is little or no dependence upon skilled help, except the normal tuning required in the life of a piano. 7

A still further feature of my invention lies in the provision of an operating mechanism for a piano which is entirely self-supporting and com-'- plete in itself and may be connected with a case or housing by a simple unskilled operation so that different cases, of many alternative styles may be interchanged for one another and connected to the operating mechanism during the normal life thereof.

Another feature of my invention is the provision of one-piece metal brackets adjustably and demountably supported on the frame back which serve to connect together the preassembled portions of the piano operating unit, which take all of the load of the movable mechanism and supports therefor, and which effectively take up most, or at least a greater portion, of the forces applied to a final assembled piano in the handling thereof.

A still further feature is the provision of remqvable adjustable pedal mechanism which opoperating unit of Fig. 1 and connected thereto into an assembled piano;

Fig. 3 is a fragmentary enlarged: cross-sectionali view approximately along the line 33 of Fig. 2, with the addition of some parts of the operating unit which are within the case at the section. line when the operating unit and case are assembled together;

Fig. 4 is a detail view of the removable assembly bracket and associated elements along the line 4-4- of Fig. 3';

Fig. 5 is a detailed and enlarged fragmentary sectional view of the leg and key bedconnection asshownin Figs. 1 and 3 and taken along the line 5'5' of Fig. 3;

Fig. 6 is a further enlarged top view of the leg connecting means in twopositions;

Fig. '7 is a view somewhat diagrammatically of the complete removable pedal mechanism illustrated in part in-Fig. 1; and

Fig. 8 is an enlarged detail. view of the ad- 'ustable limiting means for a pedal.-

For purposes of illustration my invention will be described herein as appliedto. a so-called low upright piano but it is to be understood that the invention is not limited thereto. This. piano in.- cludes a multi-part operating unit which comprises a back portion including. a frame back, with a string plate and a sounding board mounted thereon. The operating unit also includes. an action-key assembly, which latter comprises a key bed supporting keys and an action thereon in a playing position relative to the strings on the string plate. The operating unit likewise includes a bracket removably mounted in. front of the sounding board on the frame back of the back portion to in turn adjustably support thereon the playing portion of the unit. Pedals and the mechanism connecting. such pedals to the piano action are removably supported from the string plate and key bed respectively, so that keys, action, and the other movable parts may be completely regulated during the. manufacture of the operating unit. The back portion is supported on rollers or casters, and legs are removably secured to the playing. portion of the operating unit at the front thereof so that the operating unit may be moved about in the manufacturing operations without-requiring. other supporting or moving means in the absence of. a. case The operating unit may then be disassembled for shipment. The case unit for the piano of my invention is adapted to be assembled to the operating unit after the latter is reassembled. at the point of sale, or any other desired place in the complete handling of the piano.

Referring now to the operating. unitof. Fig. 1-, this includes a frame back It with a heavy wooden frame construction including upright frame members conventional in the piano industry as shown, for instance, in Heller Patent No. 2,081,704; and a sounding board H and a string plate 12 rigidly secured thereto. The sounding board H is glued to the frame back, or

back board I 0, while the string plate [2 is screwed or bolted to the frame back in the usual manner. The string plate I2 is in engagement at certain portions of its edge with the sounding board, but otherwise is free of the string plate l2, except for the operative connection through the bridges l3 and i3, for the bass and treble respectively, mounted directly on the sounding board. The bridges l3 and i3 carry the bass strings l4 and treble strings l4, respectively, tightly drawn between the tuning pins [6 (see enlarged illustration in Fig. 3) on pin blocks in the frame back, and the stationary pins SP in the string plate.

The action-key assembl is mounted forwardly of the back portion of the operating unit. A split key bed is provided for the keys, and this includes a rear portion l1. having pins 18 therein to support the action brackets l9, which in turn carry the stationary and movable parts of the action itself. Except to refer to the whip 2i, nd the hammer 22 in each individual unit of the complete action, and likewise the pivoted. hammer rest rail 23 and stationary action rail' 25, common to all units, there seems to be no necessity for describing more in detail the conventional action illustrated. Threaded pins or bolts 24 secured to the string plate, receive and support the top of each of the plurality of brackets in the action, all as shown in Fig. 1. The split key bed likewise includes a main key bed portion 26 abutting the portion. I! of the split key bed and connected thereto by a rabbeted type of connection as shown in Fig. 1.

Because of the large number of parts in the action, key-board and string assembly of Fig. 1, a schematic representation is used to simplify the illustration and indicate generally the duplication of parts; In view of the fact that it is necessary to indicate the hidden portions of the bracket and pedal mechanism in conventional dotted lines, the bridges l3 and [3' with multiple guide pins are differentiated therefrom simply by the dot and dash representation.

A key frame 2-! is supported on the portion 28 of'the key bed, and a plurality of keys 28 corresponding to the units of the action are pivotally mounted on the key frame. A capstan screw 28 at the end of each key engages a whip 2| when a key is depressed in playing, and sets into motion the parts of each unit of an action including the hammer 22, to strike a corresponding string 14 or M. The vibration of the string is transmitted through the bridge E3 or l3 to the sounding board ll.

Although the keys and action have been described together in the initial part of the specification to present the piano structure in a sequence for better understanding, actually, in the manufacturing steps, the two brackets 3| are adjustably mounted upon the completely preassembled back portion including the frame back I 0,. before the assembly of any of the playing portions of the mechanism. As is apparent from a consideration. of Figs. 1, 3 and. 4, each bracket 3| comprises preferably a cast metal member including a body portion 32 having an integral right angled flange 33 at the rear edge thereof, and including elongated apertures 34 fitting over the screws 36 in the frame back 10. The front face of the frameback I0. is bowed outwardly very slightly vertically thereof to crownjor similarly curve, the sounding board H glued thereto. To accommodate this and yet provide afirm mounting for; the bracket, a pair. of; feet 35. with a shallow depression N therebetween are provided at the back of the flange 33 so that the bracket will not rock at a vertical midpoint. Likewise, this reduces the contact of the bracket with the sounding board. To further minimize the contact, the feet do not run the full width of the flange, as is evident from the upper left hand portion of Fig. 4, which shows the rear configuration of the flange 33 and feet 35 thereon.

The screws 36 extend through the sounding board and into the wooden frame back, and are entirely independent of the string plate I 2. As a result, when the brackets 3| are supported thereon any jars, strains or the like put upon the brackets or the structure supported thereon is transmitted into the frame work and cannot affect the string plate which would be subject to cracking if the brackets were in contact therewith. The brackets 3| are adjustable on the screws 36 for the proper vertical height relative to the back portion so that the keys and action are properly positioned relative to the strings. After the desired positions of the brackets are attained, the screws 36 are tightened down to rigidly maintain the brackets on the frame back I0. Conventional wood screws 36 are illustrated, but lag screws have been found preferable because they can be provided in a heavier body, and can be tightened more rigidly to the frame back by means of a wrench.

Each bracket 3! includes an upper face or surface 31 for supporting the key bed, with an integral extension 38 extending forwardly therefrom and offset inwardly of the key bed relative to the bracket body portion 32, as is evident from Fig.

3 particularly. Apertures 39 in the extension provide for the adjustment of the connected key bed portions I! and 26 relative to each bracket after screws 40 are inserted upwardly through the apertures 39 and into the key bed before tightening the key bed to the bracket. With the key bed, key frame, keys and action supported on the brackets 3|, it is evident that these latter provide the adjustable connection between the back portion and the playing portion of the operating unit, as well as the support for the playing portion,

After assembling of the brackets 3i on the preassembled back portion of the operating unit and thereafter the assembly of the key bed, and associated elements or units, including the action itself, upon the brackets, legs 5| are removably connected with the front part of the playing portion so as to support the complete operating unit for movement through the remaining manufacturing steps. Each leg 4| has a connecting element 42 secured on the top thereof, and each connecting element as shown in Figs. 5 and 6 includes a stud 43 with sides tapered inwardly from the top and fitting into the corresponding tapered-sided aperture 44 in a plate 46. The plate 48 is mounted or set into the key bed 26 laterally of the bracket extension 38 as is shown in Fig. 3, with the outer face thereof flush with the under face of the key bed. As is evident from Fig, 6, the aperture 44 narrows from front to back as does the stud 43. In addition the corresponding side edges are beveled or tapered as mentioned above so that a firm frictional wedging engagement between the corresponding portions of the members results from hammering the member 42 slightly rearwardly into a tight connection. Thereafter, with the tail of the member 42 against the underside of the key bed, a screw 45 through a corresponding hole in the tail anchors the member to the key bed and l,

maintains the leg-key bed connection. This connecting structure permits a read assembly of the leg onto the key bed. Furthermore, the member 46 may be mounted into the key bed at various places over a considerable area so that great flexibility is provided in positioning the leg and styling the piano. With this ready connection for the legs, and one which, as will be pointed out, is independent of the piano case, legs may be interchanged for styling or repair just as the user desires.

Each leg 4| carries a. caster 48, and these with the casters or rollers 49 on the back portion, completely support the operating unit of the piano exactly as though the case orhousing was mounted thereon. Normally a dummy leg which can be identical to leg 4| is employed during the manufacturing process in order to avoid marring or otherwise injuring the leg to be used in the final piano, but it is obvious that the legs 4! to be ultimately used in the finished piano may be connected to the operating unit, if desired. Legs may be packed and shipped with the operating unit and are immediatel available therefor when such unit is reassembled after shipment from the point of manufacture.

With the action and the keys in the proper position relative to one another, the pedal mechanism is assembled onto the back portion and the playing portion. Three pedals 5!, 52 and 53 are pivotally mounted on a support 54 (Figs, 1 and '7) which in turn is rigidly secured to integral brackets 56 at the bottom part of the string plate [2. Corresponding connecting

links

51, 58 and 59 are pivotally connected to the pedals 5|, 52 and 53 respectively, and are likewise pivotall connected to additional links which in turn are mounted at their axes underneath the ke bed as is apparent from the dotted lines in Fig. 1. These extend to the corresponding parts of the piano. Because of possible confusion in illustrating all three linkages or connectors for the pedals, just the one connecting with pedal 53 and link 59 is shown in dotted lines in Fig. 1, but it is illustrative and the remaining mechanism is understandable from the complete system drawing of Fig. 7.

Reference is made to the detailed illustration of the pedal mechanism in Fig. 7, and because the elements of the connecting structure for the hammer-rail pedal 53 are illustrated in the complete general mechanism of Fig. 1', this unit will be described first. Pedal 53, as well as the other two pedals, is pivotally mounted from a pin 62 removably supported on blocks or other means 63, secured to the mounting plate 54. The vertical link 59 is connected with the pedal in a movable connection forwardly of the pin 62 so that as the pedal is depressed the link 53 is moved downwardly. The link in turn is connected to a horizontal member or link 64 in an adjustable connection at 65, and such link 64 is pivotally connected to a bracket 6'! suspended from, and secured to the under face of the key bed portion I1 as is evidenced from Fig, 1, The link 54 pivots to raise a vertical rod 68 removably connected to the hammer rail 23, so that as the rod 58 is raised,

upon depression of the pedal 53, the hammer rest rail is pivoted upwardl to carry all of the ham- Min the bass. All ofthe dampersare-connected:

treble portion 14 and a bass portion 16, each with a corresponding fiat face atthe juncture 11. The

fiat face of the rod 18 is rearwardly in the piano of. the fiat face of the rod 14. Consequently, the rod 16 may be pivoted by the pedal connecting:

mechanism connected to the rod extension 18; while movement of the extension 19 on the rod 14 actsto pivot both portions and move all of the dampers therewith away from the corresponding.

strings.

When the rod portion 16 is pivoted upon move ment of the pedal 52 as will be describechonly the bass dampers, including the damperl'l, are moved away from the strings so that there is no damping on the bass strings I4. This operation is'accomplished by the link 58 connected to the pedal 52 at one end and to a horizontal link or member 8| at the other end. The member 8| is suspended from a bracket 82 and connected to a vertical rod83, which in turn supports thereon, and is connected thereto, the arm extension '18 on the damper rod. This latter mechanism is substantially duplicated in the pedal mechanism, having a horizontal link'84 connected to the vertical link 51 and pivotally suspended from a bracket 86 secured to the key bed portion IT. The vertical rod 81 connects the lifter rod ex-' tension 19 and the link 84 to pivot the entire damper rod 12 as has just been explained;

The pedal units are all connected to their respective movable parts in the piano action and adjusted relative thereto so that those parts exert a downward force on the horizontal links 64, 8| and 84 at the outer ends thereof and these in turn raise the corresponding pedals 53, 52 and 5|, respectively. Normally, the upward movement is limited by a toe rail as it was called in the prior art upright pianos. The toe rail was of wood and normally notched to accommodate the three pedals. A felt member at the top of the notch acted as a stop or buffer against which a corresponding pedal would hit, but even with this padding an undesirable noise was generated in the case so that the operation of pedals was normally audible. Objectionable prior practices and structure have been eliminated and an improved adjustable means is provided with a stop for each of the pedals 5i 52 and 53, in the present invention.

Such adjustable means is illustrated in Fig. 8

and comprises a screw or adjustable member 88 extending into the wooden mounting plate 54. The shank of the member 88 extends through a corresponding aperture 89 as shown for the pedal 5| in Fig. 8, and the movement of the pedal is limited by a felt or noise-proof bushing 91 carried on the shank and limited by the adjusting head 92 on the member 88. It has been found in extensive operation of the mechanism, that this means not only provides a quiet operation for each pedal, but also provides a simple means for finely adjusting the top limit of movement of'the pedal with relation to all of'thestructure to which the pedal is connected.

The pedal mechanism of the present invention therefore, provides adjustable noiseless operation, and simple structure which is readily mounted upon, and demountable from, the operating 'unit in the original manufacture thereofi After shipment to the point of destination the pedal mechanism maybeset up very quickly; andi dueto the fact that the operating unit is entirely" open and availableto the operator, it maybe? quickly adjusted forthe most desirable playing condition;

It is evident from the above'description, that all of the operatin parts of the piano mechanism arenow in position for normal operation; and with this entire mechanism open and completely available to workmen, the keys and action, as well as'the' strings can beregulated and adjusted to a final degree. The'operatingi unit is supported in normal fashion and all ofthe parts are' in final position with respect to one another, ready'for'the adjustment of the movableparts of the key and action mechanism. Thus the piano operating unit can be putin' a condition ready for playing use, and just as complete in this respect as was possible in the former methods of manufacturing during which either the entire case or atleast parts thereof were assembled to the operating elements. The case was then moved with theremaining piano elements during many of the steps in the completeprocess of manufacturing apiano. In the present invention, however, precision parts which are standard toeach general type of piano can: be assembled into the operating unit without any.

consideration of the ultimate styling ofthe piano as represented in the case, andbecause the operating unit is assembled toclose tolerances, cases made according to predetermined dimensions can be assembled thereon Without the previously, required hand fitting.

An illustrative case is shown in Fig. 2 in condition to be slipped over the front of the operating unit of Fig. 1. There are-provisions for effecting the ultimate connection betweenthe operating unit and the case, in the adjustable brackets 94 (Fig. 1), which are shownassembled onto the operating unit during the manufacture thereof. member with flanges or extensions at right angles to one another, and with the flange 95'adjustably secured to the frame back 10 by means of screws 91 extending through elongated apertures 98 in the flange. This can be moved laterally so as to bring the outside face of the other flange 99 fiush With the face lUl at the end of the frame back l0. Inasmuch as the string plate I 2 is a cast metal member and is not machined after casting, it is normally found that the outer edge is rough, and therefore the plate is set in slightly at its end I02 from the face IOI of the frame back. The bracket 94, however, as previously mentioned is adjustable laterally so that it may be moved beyond the face 101 of the string plate until the face of the flange 99 is in the same plane with the facel OI of the back.

After the operating unit is complete as shown in Fig. 1, and as previously described, then it is adjusted and regulated to final condition, and thereafter the manufacture of the unit is complete. t may then be readily disassembled for shipment, and normally can be reassembled at its destination without disturbing the regulation and adjustment. In the disassembly, the action is' removed from the bolts 24 and'pins 18; The pedal mechanism is disassembled from the string plate and key bed. The complete portion including key bed, key frame, and keys may then be removed from the brackets 31, meanwhile removing the legs-41 Thereafter'the brackets are removed'andiallo'fthe various preassembled por tions just"described', including the complete back Each bracket 94 comprises an elongatedportion, are all packed into compact spaces either in racks or boxes. Furthermore, in view of the configuration of such parts or portions, and the varying dimensions thereof, a railroad car, a truck, or other conveyance can be packed with such parts or portions in a, manner such that the entire interior or any designated part thereof, can be filled up completely, utilizing all the space for which the shipper is liable. The invention materially expedites the original handling of the structure, and the shipment of the piano mechanism is expedited over the present methods wherein the entire assembled piano is shipped as one unit.

At the point of destination for the operating unit, the various parts can be reassembled in the manner previously described. The reassembly can be accomplished by relatively unskilled help. The desired case style which can be available at such destination, can then be assembled on to the complete operating unit in a manner as will be described.

The assembled piano case shown in Fig. 2 can be supplied in assembled or disassembled form. As illustrated in assembled form, the top T is adapted to be hinged H to corresponding hinges H on the operating unit. Also, the front panels F, and F are removable in accordance with the present conventional practice in upright piano cases. The operating unit can be moved into the case, or the case fitted over the operating unit in a telescoping manner, until the rear edges thereof are in abutting engagement with the front face of the rims or flanges I03 extending outwardly from the faces IBI. With the panels F and F removed, screws I04 may be inserted through apertures I09 in the flanges 99 on the operating unit brackets to secure the sidewalls D of the case thereto. Such sidewalls D abut the faces [6| of the frame back In as is shown in Fig. 3. Screws [t extending through the rim or flange I03 provide a rigid connection between the case and playing or operating unit along the entire length of such rim,

Angle irons 167 are secured to the frame back in near the lower portion thereof to secure the case thereto at those points on the operating unit, and angle irons I08 (Figs. 1 and 4) secured to the key bed are apertured to receive screws threaded into the front extensions on the case. g

It is apparent from the preceding description and drawings that the present invention provides a preassembled operating unit which is entirely self-supporting and complete independently of a piano case or housing therefor. Although the operating unit and the piano case can be produced by the same manufacturer, assembled together, and then shipped in complete assembled form, my invention also provides for the manufacture of the operating unit, comprising the playing mechanism of the piano entirely independently of the case. Various styles and designs of cases can be made by cabinet makers, or other manufacturers familiar with cabinet construction independently of any knowledge of piano mechanisms themselves. The dimensions and configurations of the cases can be predetermined in accordance with plans of the operating unit which can be made readily available, and because the operating unit is assembled from standard uniform parts, any case built according to predetermined plans can be assembled in a very simple fashion by the merchandiser, or by the ultimate purchaser himself.

Furthermore, my invention not only provides for the initial manufacture of this piano at lower cost, but with a standard uniform construction to provide an improved instrument, it also provides an operating mechanism and means for connection thereof with a case such that an owner can himself disassemble and assemble a case on an operating unit to provide new styling as such might seem necessary in the home, in places of amusement, or otherwise. This makes it possible to purchase a high quality piano mechanism and then at relatively low cost maintain the case in style as ones tastes change over the years.

Although the invention has been described specifically with reference to the preferred embodiment of the invention, it is to be understood that such invention is not to be so limited, since changes and modifications can be made therein, both as to an upright piano, and other types of pianos which are within the intended scope of this invention as defined by the appended claims.

I claim:

1. A piano structure for use in an enclosing case and being complete for playing independently of such an enclosing case, said piano structure comprising a frame, string supports on said frame having strings positioned thereon, a sounding board secured to said frame, brackets secured to said frame and extending forwardly thereof, an action-key assembly mounted on said brackets for operative playing engagement with said strings, supporting means in front of and operatively connected to said frame, and means on said frame and said action-key assembly for detachably securing a case thereto.

2. A piano structure in accordance with claim 1 in which said supporting means comprise legs which are removably secured to said action-key assembly.

3. A piano structure in accordance with claim 1 in which said action-key assembly includes a split key bed, one portion of which supports said piano keys and the other portion of which supports said piano action.

4. A piano structure in accordance with claim 1 in which said frame includes a supporting back structure and a string plate secured thereto and said string supports are provided on said string plate.

5. A piano structure for use in an enclosing case, said piano structure comprising a frame, string supports on said frame having strings positioned thereon, a sounding board secured to said frame, brackets secured to said frame and extendmg forwardly thereof, a key bed mounted on said brackets having keys supported thereon, a piano action supported on said frame in cooperative position with respect to said keys and in operative playing engagement with said strings, legs in front of said frame and separably connected to said key bed, and means on said frame and said key bed for detachably securing a case thereto.

6. A piano structure in accordance with claim 5 in which said key bed includes two portions both of which are mounted on said brackets, one portion of said key bed serving to support said piano keys and the other portion of said key bed serving with said frame to support said piano action.

'7. A piano structure in accordance with claim 5 including a pedal mechanism for operative connection with said action, said pedal mechanism being removably mounted on said frame and said key bed.

8. In a knock-down piano having an enclosing case, a piano structure for use in said enclosing case, said structure being completely playable and entirely self-supporting independently of said case and including in combination a frame, string supports on said frame having strings positioned thereon, a sounding board secured to said frame, brackets removably secured to said frame and extending forwardly thereof, an action-key assembly mounted on said brackets for operative playing engagement with said strings, separable supporting means in front of and operatively connected to said frame, and means on said frame and said action-key assembly for detachably securing said case thereto.

9. In a piano structure of the knock-down piano of claim 8, said separable supporting mean therefor comprising a ,pair of supporting legs operatively connectible with said frame and operatively di'sconnectible therefrom as required during the manufacture and assembly of the piano structure and piano.

CHARLES FREDERICK STEIN.

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

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