US2538801A

US2538801A - Piano sounding board construction

Info

Publication number: US2538801A
Application number: US772315A
Authority: US
Inventors: Edward J Schneider
Original assignee: BALDWIN CO
Current assignee: BALDWIN Co
Priority date: 1947-09-05
Filing date: 1947-09-05
Publication date: 1951-01-23
Anticipated expiration: 1968-01-23

Description

INVENTOR.

ATTORNEY EDWARD J. JZZWIM E. J. SCHNEIDER PIANO SOUNDING BOARD CONSTRUCTION Filed Sept. 5, 1947 Jan. 23, 1951 isoiinding board emhodyingmy invention.

Figure 2 is. a sectional view thereof taken .on

Patented Jan. 23, 1951 f UNITED STATES PATENT OFFICE' 4f. 11 2,538,801

PIA-NO- SOUNDING BOARD co sTm'ic'rIoN:

Edward 11.. Schneider; Cincinnati, Ohio, assignor to The. Baldwin. Company, Cincinnati, Ohio, a.

corporation of Ohio.

11 Claims.

My invention relates to pianos and; more. particularly to piano sounding boards.

Itis a. primary object of the: invention to increase the initial volume of piano tones through fan, improved sounding. board c,onstruction.v vAlthough the. design. of pianos isiar from being an.- exact. science; certain facts are known regarding. the acoustic-response of sounding-board assemblies. For instance,. in the upper or treble range, the higher the frequency of, the note played; the. less the. sound is-emitted from the .sou-nding. board-itselt, and the more; the sound is emitted) by the string-supporting metal plate. "A1507" the more important resonant. pointsoi the sounding board occur in the..middle frequency 'range of. the keyboard. It is also known-that the :area. of the sounding boa-rd corresponding to this jmiddle range is appreciably sensitive to changes in construction.

It is a. usual practice in the construction. of (pianos. to. employ reinforcing bars orribs on the .opposite side. of. the sounding board from the string bridge. and running transversely. thereto. .11; is 'a. further practice. togradually reduce the gc-rossi-sectional area (usually by reducing the :height.) of. the. above-mentioned ribs near their this. latter practice being commonly known as feathering. It is an additional practice in ,the construction of pianos to feather the ribs in. a. manner such. that. a. line joining the starting 1 points oi the feathering would. describe a shape substantially similar toy that. of the inner rim of the pi'anoand/Or similar to the shape of the piano case, 1 f I.' have. discovered. that the initial volume. of. the piano:tones is measurably increased if the ribs are feathered. in a manner such that the unicathered portion of, each rib. is equally disposed on. either side of the bridge. Al hou I pr fer .to carry out. this. equidistan'ce with respect to all ribs, certain practical. design considerations. may require. deviations from saidequidistance as will he described hereinafter. I

Following is a. specific description. of my invention, reference. being made to the accompanying drawings wherein: p

Figure 1. shows the under, sideloi. a grand piano "the; line C.'C..

.Wi-th. referenceto Figure. 1 the. sounding board is supported in the piano. by the. inner rim 3. '.(.The. piano case. has. been. omitted for simplificar ltionj he! string. bridge. 41,. o al. \zvhichv the vi.- Ltt l i mouilfiedr n h e.

surface of. the soundin .of the piano tones. is measurably increased if W= X on all ribs- In. the instance of. a. grand piano. (as illustrated in Fig. l). where the. bridge 1 maybe. bent. double in order to provide a. short leg 6 for. the bass strings, the feathering is equildistantfrom the bridge in the sense that the starting point of. the feathering on one end of any one rib. is thesame distance from the nearer bridge section as the starting point of the feathering on the other end is from its nearer bridge section. For, practical; considerations, exception must be made regarding. the feathering of. the

; first one. or twov ribs where occurs the abrupt change from one bridge section crossing a rib to "shoul two bridge sections crossing a rib. Also,v for practical reasons I may deviate from the equidistance. teature on the first two or three ribs at "the trebleend of the sounding board. This may be necessary S0. as to provide more unfeathered len th than would be available by maintaining the equidistance because a certain minimum. un-

feathered length must be retained on the ends of each rib in order to insure the best possible tone for the treble notes corresponding to said ribs.

In view of the previously presented facts regarding. the acoustic response of sounding board assemblies. the, above-mentioned deviations from equidistance are of no appreciable consequence.

Since. rib dimensions are being compared quantitatively when the term equidistant is used. and since some sort of manufacturing tolerances are to-be expected, I Specify-thefollowing as being tolerances within which my eifects are most perfectly attained, it being understood that' depar- .tures from them can still be considered as being within the spirit of this invention. erancesshould not be confused with the design (These toldeviati'ons mentioned above.) The amount'of varia on f romf the above-defined equidistance referablynot exceed 2% of the overall rib leg- (designated as'Z' in Big. 2) as measured-between the intersections of the 'ribs with the inner rim. Expressing this mathematically,

the quantity 3 should be between -2 and +2; for instance, in a 25 inch rib with an unfeathered length Y of 12 inches, the dimensions W and Xcould diifer as much as inch, being 6% and 5 /4 or 5% and 6 respectively.

Modifications can be made in my invention without departing from the spirit of it. Having described my invention in an exemplary embodiment, what I claim as new and desire to secure by Letters Patent is:

1. In combination in a musical instrument, a sounding board, a bridge structure mounted thereon, and reinforcing ribs mounted on said sounding board on the side opposite from said bridge structure and being arranged transversely thereto, said ribs being feathered toward both ends beginning at pointssubst'antially equidistant from said bridge structure for each such rib.

2. In combination in a musical instrument, a sounding board, a bridge structure mounted thereon, and reinforcing ribs mounted on said sounding board on the side opposite from said bridge structure and being arranged transversely thereto, said ribs being feathered toward both ends, the majority of said ribs having an unfeathered portion substantially equally divided .in length by said bridge structure.

3. In combination in a musical instrument, a sounding board, a bridge structure mounted thereon, and reinforcing ribs mounted on said sounding board on the side opposite from said bridge structure and being arranged transversely thereto, said ribs being feathered toward both ends, said bridge structure having a part crossing all ribs, and another part crossing certain of said ribs, the majorityv of said ribs which are crossed singly, having unfeathered lengths subposed on one side of said bridge structure and the length of unfeathered rib-portion disposed on the other side of said bridge structure does not exceed two per cent of the total length of said rib as measured between the intersections of said rib with said inner rim.

'7. In combination in a musical instrument, an inner rim, a sounding board supported thereby, a bridge structure mounted on said sounding board, and reinforcing ribs mounted on said sounding board on the side opposite from said bridge structure and being arranged transversely thereto, said ribs being feathered at both ends, the majority of said ribs being feathered in a manner such that the difference between the length of unfeathered rib-portion disposed on one side of said bridge structure and the length of unfeathered rib-portion on the other side of said bridge structure does not exceed two per cent of the total length of said rib as measured between the intersections of said rib with said inner rim.

8. In combination in a musical instrument, an inner rim, a sounding board supported thereby,

a bridge structure mounted on said sounding that the difference between the length of unstantially bisected by said first mentioned bridge part, and the majority of said ribs crossed by both bridge parts having unfeathered portions which, as to each such rib, extend for substantially equal distances from the adjacent bridge parts.

4. In combination in a musical instrument, a sounding board, a bridge structure mounted thereon, and reinforcing ribs mounted on said sounding board on the side opposite from said bridge structure and being arranged transversely thereto, said ribs. being feathered toward both ends in a manner such that an unfeathered portion of each rib extends beyond said bridge. structure on one side substantially the same distance that another unfeathered portion of the same rib extends beyond said bridge structure on the other side.

5. In combination in a musical instrument, a sounding board, a double bridge structure mounted thereon, and reinforcing ribs mounted on said sounding board on the side opposite from said double bridge structure and being arranged transversely thereto, said ribs being feathered at both ends in a manner such that the unfeathered portion of each rib is equally disposed on either side of the area lying between the longitudinal center line of said double bridge structure;

6. In combination in a musical instrument, an

inner rim, a sounding board supported thereby,

a bridge structure mounted on said sounding board, and reinforcing ribs mounted on said sounding board on the side opposite from said bridge structure and being arranged transversely thereto, said ribs being feathered toward vboth (iii ends in a manner such that the difference between the length of unfeathered rib-portion disfeathered rib-portion, disposed on one side of said first mentioned bridge part and the length of unfeathered rib portion on the other side of said first mentioned bridge part does not exceed two per cent of the total length of said singly crossed ribs as measured between the intersections of said singly crossed ribs with said inner rim, and the majority of said ribs crossed by both bridge parts having unfeathered portions which, as to each rib, extend from the adjacent parts for distances which differ by not more than two per cent of the total length of said ribs crossed by both bridge parts as measured between the intersections of said rim with said inner rim.

9. In combination in a musical instrument, an inner rim, a sounding board supported thereby, "a single bridge structure mounted on said sounding board and reinforcing ribs mounted on said sounding board on the side opposite from said single bridge structure and being arranged transversely thereto, said ribs being feathered toward both ends in a manner such that the difference between the length of unfeathered ribportion disposed on oneside of said single bridge structure and the length of unfeathered rib-portion disposed vonthe other side of said sin glle bridge structure does not exceed two per cent of the total length of said rib asmeasured between the intersections of said rib with said inner rim.

10. In combination in a musical instrumentgan inner rim, a sounding board supported thereby,

a double bridge structure mounted on said sounding board and reinforcing ribs mounted on said sounding board on the side opposite from, id

double bridge structure and being arranged portion on the other side of said area does not exceed two per cent of the total length of said a 10 Number metrically disposed with respect to said bridge structure.

EDWARD J. SCHNEIDER.

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

UNITED STATES PATENTS Name Date 1,680,180 Siegel -7 Aug. 7, 1928