US1747729A - Sounding-board bridge for pianos - Google Patents

Description

Feb. 18, 1930. F. MOSER 1,747,729

SOUNDING BOARD BRIDGE FOR PIANOS Filed March 25, 192e 2 sheets-sheet 1 I I I I I l 6 M i WMM L A 11 g 12 1 f nnlnlnnnnlnn Qnlnrl/ L 2 11 5 5 i *3 fg H97 52 6 7g l 8 /5 9 f Feb. 18, 1930. F. MOSER .1,747,729

SOUNDING BOARD BRIDGE FOR PIANOS Filed March 25, 1926 2 Sheets-Sheet 2 Patented Feb. 18, 193() I p UNITED STATES AreNT ori-ICE FELIX MOSER, OF HOLLAND, MICHIGAN SOUNDING-BOARD BREDGE FOR EPIANOS Application iiled March 25, 1926. Serial No. 97,284.

The invention relates to improvements in grand piano showi the invention in plan soundingboard bridges and fastening them and the manner ot securing the stringplate between the soundingboard and the plate. and soundingboard to the frame of the piano. The. objects of the improvement are, to pro- Figure l is a cross-section on line A-A ot vide bridges which will, first, improve the Figure 9. v 55 quality of tone by their greater resistance and In Figures l and 2 the bridge 3 is a strip of by eliminating the short lengths of strings bewood, similar to the kind commonly used. tween the plate and the old type bridge, The bridge 3 is rabbeted 4 to allow the plate 5 second, will simplify construction resulting to tit into it, and is fastened to the soundingin greater dependability, third, will reduce board 6 in the usual way. It is also :fastened 60 cost ot production. to .the plate (5) by screws 8 or bolts 9. The The invention consists of the matters herein st rlng l0, stretched over the bridge 3 to the described and pointed out in claims. hitchpin ll, imparts its vibrations through The so-called dead ends of the strings, bethe bridge 3 to the soundingboard 6, the ribs tween the bridge and the hitchpins of the .7 acting as conductors of these vibrations to G5 plate, anywhere between 2 and 6 inches long all parts of the board. The bridge may be are always a source of mostly undesirable notched to provide accurate stringlengths overtones. and projects above the plate for that purpose. This dead end is to be practically elimi- Accurate stringlength may also be obtained nated by extending` or enlarging the string by crosswires l2, in which case the bridge 79' plate so that it will fully or partly cover the may be level with the plate. bridge. Plate and bridge will be rigidly fas- Figures 3 and l show a sectional bridge 3, tened to each other. Rigidity being the foreconsisting of blocks ot' wood ot convenient most requirement orp a pianobridge to stop and size and shape, beingl placed on the sounding- L 5 receive the vibration of the usually high tenboard 6, over the ribs 7, on a line where the sioned strings at proper string lengths. bridge should be placed. rlhe sections are The plate thus becomes part of the bridge, fastened to the soundingboard 6 and its ribs 7, furnishing most of that resistance. and to the plate 5, by means of glue, and

In the accompanying drawing, Figures screws S or bolts 9. T he string l0, stretched 39 1 3-5-7 represent four similar cross-secover the crosswire l2 to the hitchpin l1, im- 5' tions, showing lfour types of bridges, all tour parts its vibrations through the plate 5 and involving the saine acoustic principle, the bridge 3, to the soundingboard 6, the ribs 7 adaptability of each depending on the conactingas conductors of these vibrations to all struction and direction of the grain of the parts of the board. soundingboard or whether the plate be made In Figures 5 and G tlie bridge 3 is a strip of ol metal or wood, or upon high or low tension wood, of the usual lengthwise shape. The of the scale. bridge 3 is 'fastened to the soundingboard 6 Figures 2-4--6-8 represent cross-sections in theusual way, and to the plate 5, by means en line l-l of Figures 1 -3-5-7 respecof glue, and screwsSor bolts 9. The string l0, tively, showing the bridges on a line across stretched over the crosswire l2, to the hitchthe strings.k -pin ll, imparts its vibrations through the `Figures 1-2-3-4 show the bridge in conplate 5, and the bridge 3, to the soundingjunction with a ribbed soundingboard as it is board 6, the bridge 3 acting as conductor of generally used today. The grain of the these vibrations to all parts of the board in soundingboard runs in the same direction absence of the ribs. Withthe bridge. :Figures 5-6-7-8 Show Figures 7 and 8 show a sectional bridge 3, the bridge in conjunction with a soundingconsisting of blocks of wood of convenient board that is not ribbed. The grain of the size and shape, being placed on the soundingsoundingboard runs crosswise to the bridge. board 6 at convenient distances from each Figure 9 is a view of the treble side of a other on a line where the bridge should be, @W

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A strip 13 is glued to the other side of the soundingboard 6, on a line corresponding to the sectional bridge 3. Strip 13, soundingboard 6, bridge 3, and plate 5, are fastened by means of glue, and screws 8 or bolts 9. The string 10, passing over the crosswire 12, to the hitchpin 11, imparts its vibrations through the plate 5, and the bridge 3, to the soundingboard 6, the strip 13 acting as conductor of vibrations to all parts of the board in absence of the ribs.

ln Figures 9 and 10 the plate (5) is fastened to the frame (14) by screws (15), which run through the blocking or bushings (16), which regulate the height of the string plate, and through the soundingboard (6) which is glued on to the frame (14).

At B a section ofthe stringplate and soundingboard is broken away to expose the frame (14) of the piano on to which is glued the outer rim (18'). Forsimplicity only one string to the unison is shown. The strings (10) run from the tuning pins (17) over the cross vwires or elevations (12) to the hitclipins (11).

A sectional bridge (3) asdescribed in Figures 3 and 4 is shown here. The various sections (3) 'are fastened between the stringplate (5) and the soundingboard (6) by screws which run into the ribs (7).

The main functions of a soundingboarc bridge are: to stop the vibrations of the strings at the proper stringlength and to convey these vibrations to the soundingboard, where they are amplified. Y

Rigidity or resistance, being the first requirement of a bridge, is acquired by rigidly fastening the bridge between the plate and the soundingboard. Either of the bridges or a combination of them lcan be used in either upright or grand pianos, the plate being made of metal or Wood or whether the soundingboard be ribbed or not.

This specification applies to treble or bass bridges both.

These bridges relieve the immense strain on the soundingboard and its ribs caused by the downward pressure of the strings on the old type bridges. Thus the sound- -ingboard is able to vibrate more freely and naturally. The crowning of the soundingboard which is undesirable becomes unnecessary with these new bridges.

)Vhile wood is preferred for this bridge, the use of metal may be resorted to with advantages, mainly in cost of productionnamely, the bridge may be cast onto the plate, either sectionally or in full length and fastened to the soundingboard as explained.

I claim:

1.v In a stringed musical instrument, the combination of a stringplate with a soundcrosswires for the purpose of terminating the active or live part of the strings and is glued to a soundingboard; extending said stringplate into the rabbet of the bridge and fastening said stringplate to the bridge by screws or bolts.

2. In a stringed musical instrument, the combination of a ribbed soundingboard, a stringplate and a sectional bridge, thesections of the bridge `being placed over each rib of the soundingboard respectively, the stringplate having notches, crosswires or elevations for the purpose of terminating the active or live part of the strings and is extended over said sections of the bridge, acoustically and mechanically forming a part of said bridge, the soundingboard, stringplate and the sectional bridge being fastened together by screws or bolts piercing the different sections of the bridge and the ribs of the soundingboard.

3. In a stringed musical instrument, the combination of a bridge which is 'fastened to a soundingboard, and a stringplate having notches, crosswires or elevations for the purpose of terminating the active or live part of the strings, said stringplate being eX- tended and fastened over the bridge, acoustically and mechanically forming a part of said bridge.

4. In a stringed musical instrument, the combination of an unribbed soundingboard having a strip glued across the grain on its reverse side on a line with the bridge, a stringplate having notches, crosswires or elevations for the purpose of terminating the active or live part of the strings, and a sectional bridge, the respective sections being placed at convenient distance from each other between the stringplate and the'1`05 soundingboard, said strip and stringplate acoustically and mechanically forming a part of said sectional bridge, being fastened together by screws o r bolts piercing the different sections 'of the bridge and the soundingboard.

5. In a stringed musical instrument, the combination of a soundingboard, a stringplate and a sectional bridge, the respective sections of wliichare located on the under` side of said stringplate at convenient distance from each other and are substantially of the same material the stringplate is made of; said stringplate having Vnotches crosswires or elevations on its upper side for the purpose yof terminating the active 'or live part of thev strings, acoustically and mechanically forming a part of said sectional bridge, and is secured to the soundingboard by screws or bolts, Which pierce the sections of the bridge. y

Y FELIX MOSER.

ingboard bridge, which is rabbeted to fit the corresponding edge of said stringplate,

i notched on the opposite edge 0r havingV

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