Piano or grand piano with strings and a sound bridge with reduced mass and improved tonal quality

Abstract

The present invention relates to a piano or a grand piano with a resonance board and strings which rest on a sound bridge with two longitudinal faces. Such a sound bridge serves to transmit vibration energy which is output by the strings of the instrument to a resonance board. The invention is based on the realization that, on the one hand, the rigidity of the sound bridge must be maintained at the locations at which it is in contact with the strings and the resonance board. On the other hand, it is advantageous if the mass of the sound bridge is reduced. For this reason, according to the invention it is proposed that the sound bridge have a first cutout and a second cutout, wherein the two cutouts are arranged on the two longitudinal edges of the sound bridge which lie opposite one another.

Claims

1. A piano or grand piano, with a resonance board and strings, which rest on a sound bridge (12) with two longitudinal faces (13a, 13b), characterized in that the sound bridge (12) has a first cutout (20a) and a second cutout (20b), with the two cutouts (20a, 20b) being arranged on the longitudinal faces (13a, 13b) of the sound bridge (12) that lie opposite each other; the two cutouts (20a, 20b) run over an entire length of the longitudinal faces (13a, 13b) of the sound bridge (12) with the exception-of portions adjacent to the two opposing ends (22, 24); wherein a relative reduction in a component volume varies over a length of the sound bridge (12) in a longitudinal direction by varying the depth of the two cutouts (20a, 20b) in the sound bridge (12) inwards relative to a vertical axis (21) of the sound bridge (12) where more material is removed at low frequencies and less material is removed at higher frequencies; the sound bridge having high rigidity at a contact surface to the resonance board.

2. The piano or grand piano according to claim 1, further characterized in that the two cutouts (20a, 20b) are arranged and designed such that they are approximately symmetrical in relation to a vertical axis (21) of the sound bridge (12) within a cross section of the sound bridge (12).

3. The piano or grand piano according to claim 1, further characterized in that, in addition to the cutouts (20a, 20b), a concavity (C) is provided in one of the two opposite-lying longitudinal faces (13a) in a portion of the sound bridge (12) that is provided for accommodating the strings of a high descant, and that this concavity (C) in a cross section of the sound bridge (12) occupies a transition region from a side that is adjacent to the resonance board (10) to the longitudinal face (13a), wherein concavity (C) is formed inwardly in the sound bridge relative to the vertical axis (21).

4. The piano or grand piano according to claim 1, further characterized in that a relative reduction in a component volume over a cross section of the sound bridge (12) is between 3 and 10%.

5. The piano or grand piano according to claim 1, further characterized in that the cutouts (20a, 20b) have a circular cross section.

6. The piano or grand piano according to claim 2, further characterized in that, in addition to the cutouts (20a, 20b), a concavity (C) is provided in one of the two opposite-lying longitudinal faces (13a) in a portion of the sound bridge (12) that is provided for accommodating the strings of a high descant, and that this concavity (C) in a cross section of the sound bridge (12) occupies a transition region from a side that is adjacent to the resonance board (10) to the longitudinal face (13a), wherein concavity (C) is formed inwardly in the sound bridge relative to the vertical axis (21).

7. The piano or grand piano according to claim 2, further characterized in that a relative reduction in a component volume over a cross section of the sound bridge (12) is between 3 and 10%.

8. The piano or grand piano according to claim 1, further characterized in that a relative reduction in a component volume over a cross section of the sound bridge (12) is between 5 and 8%.

9. The piano or grand piano according to claim 3, further characterized in that a relative reduction in a component volume over a cross section of the sound bridge (12) is between 3 and 10%.

10. The piano or grand piano of claim 1, further comprising a bridge cap (14) on a top side of the sound bridge (12).

11. A piano or grand piano, comprising: a resonance board and strings, which rest on a sound bridge (12) with two longitudinal faces (13a, 13b), wherein the sound bridge (12) has a first cutout (20a) and a second cutout (20b), with the two cutouts (20a, 20b) being arranged on the longitudinal faces (13a, 13b) of the sound bridge (12) that lie opposite each other; the two cutouts (20a, 20b) run over an entire length of the longitudinal faces (13a, 13b) of the sound bridge (12) with the exception-of portions adjacent to the two opposing ends (22, 24); wherein a relative reduction in a component volume varies over a length of the sound bridge (12) in a longitudinal direction by varying the depth of the two cutouts (20a, 20b) in the sound bridge (12) inwards relative to a vertical axis (21) of the sound bridge (12) where more material is removed at low frequencies and less material is removed at higher frequencies; and a concavity (C) is provided in one of the two opposite-lying longitudinal faces (13a) in a portion of the sound bridge (12) that is provided for accommodating the strings of a high descant, and that this concavity (C) in a cross section of the sound bridge (12) occupies a transition region from a side that is adjacent to the resonance board (10) to the longitudinal face (13a), wherein concavity (C) is formed inwardly in the sound bridge relative to the vertical axis (21); the sound bridge having high rigidity at a contact surface to the resonance board.

12. The piano or grand piano of claim 11, further comprising a bridge cap (14) on a top side of the sound bridge (12).

13. The piano or grand piano according to claim 11, wherein a relative reduction in a component volume over a cross section of the sound bridge (12) is between 3 and 10%.

14. The piano or grand piano according to claim 11, wherein a relative reduction in a component volume over a cross section of the sound bridge (12) is between 5 and 8%.

15. The piano or grand piano according to claim 11, wherein the two cutouts (20a, 20b) are arranged and designed such that they are approximately symmetrical in relation to a vertical axis (21) of the sound bridge (12) within a cross section of the sound bridge (12).

16. The piano or grand piano according to claim 11, wherein the cutouts (20a, 20b) have a circular cross section.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) Further details and advantages of the present invention are described in the following on the basis of preferred exemplary embodiments. Shown are:

(2) FIG. 1 a plan view of a resonance board with a sound bridge; and

(3) FIG. 2 a cross-sectional view along the line A-A from FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

(4) FIG. 1 shows in plan view a symbolically illustrated resonance board 10, which is part of a strings instrument, such as, in particular, a piano or grand piano. Attached to this resonance board 10 is a bridge 12referred to in the following as a sound bridgethis attachment preferably provided by adhesive bonding. In the illustrated example, the bridge 12 runs on the top side of the resonance board 10 over a substantial distance. It can be seen that the bridge 12 does not run in a purely rectilinear manner, but rather has several bends or curves.

(5) The bridge has essentially the same width everywhere over its entire longitudinal extension. Its longitudinal extension is substantially greater than its width.

(6) The bridge thus has a first bridge end 22 and a second bridge end 24. It is oriented in FIG. 1 with its top side facing the viewer and lies with its bottom side (not seen) on the resonance board 10. Its left side and its right side are identified here in a simplified manner as longitudinal faces 13a and 13b. They run over the entire length of the bridge 12.

(7) FIG. 2 is a cross-sectional illustration along the line A-A (FIG. 1). A cross section shown in this way is thus a section that, in relation to the two sides of the bridge or the longitudinal faces 13a, 13b, runs nearly perpendicularly.

(8) The sound bridge 12 has a bridge cap 14 on its top side. In addition, a plurality of bridge pegs 16, which, in this case, do not guide illustrated strings, are mounted there. The strings can be induced to vibrate by a plurality of hammer heads (not illustrated) and their vibrational energy is transmitted via the sound bridge 12 to the resonance board 10.

(9) In the preferred embodiment, the sound bridge 12 has a length of about 150 cm, a heightincluding the bridge cap 14of about 3.4 cm and a width of about 3.4 cm. It is noted that the dimensions of sound bridges can be quite different. This usually depends on the type of instrument in which they are employed. In particular, the sound bridge lengths can be up to 250 cm.

(10) It can be seen in FIG. 2, in particular, that the sound bridge 12 has cutouts 20a and 20b, which will be referred to as fillets and described in detail below, on each of its two sides or longitudinal faces 13a, 13b. The first fillet 20a is located on the left side or on the first longitudinal face 13a (with reference to the illustration in FIG. 2) of the sound bridge 12 and the second fillet 20b is located on the right side or on the second longitudinal face 13b. In the preferred embodiment, the two fillets 20 are formed and arranged in such a manner that they are symmetrical with respect to the vertical axis 21 of the cross section depicted. The two fillets 20 are shaped similarly to the arc of a circle, which, in this case, has a radius r of 6 mm along the section A-A (FIG. 1). Its innermost point projects in each case by a distance a (here, 3 mm) into the sound bridge 12. Accordingly, each of them extends vertically (FIG. 2) along the sides or the longitudinal faces 13a, 13b of the sound bridge 12 by the length b (here, 10 mm). The top edges of the fillet 20 are located at a distance c (here, 9 mm) from the top edge of the sound bridge 12 or, more specifically, from the top edge of the bridge cap 14.

(11) It has been found that it is advantageous when the dimensions of the fillets 20 along the sound bridge 12 are varied and namely in such a manner that more material is removed at low frequencies and less material is removed at higher frequencies. This is accomplished during fabrication in that the depth of penetration of the cutting tool into the blank of the sound bridge 12 is altered. Preferably, the relative reduction in the component volume varies over the cross section by between 5 and 8%. Thus, in the preferred embodiment, for example, the fillets 20 have the following dimensions at the place marked by the arrow B (FIG. 1):

(12) r=6 mm; a=3.8 mm, b=11 mm, c=9.5 mm.

(13) Preferably, the fillets 20 extend nearly over the entire length of the sound bridge 12 along the longitudinal faces 13a, 13b. However, they end at a predetermined distance before the first bridge end 22 or before the second bridge end 24. In the preferred embodiment, the fillets 20 run toward their ends along the arc of a circle, this being determined essentially by the milling process during their processing.

(14) It can further be seen in FIG. 2 that the cross section of the sound bridge 12 has another concavity (or fillet) on the bottom left side (arrow C) or longitudinal face 13a. This concavity or fillet in the longitudinal face 13a is not provided over the entire region or over the entire length of the sound bridge 12, but rather, first and foremost, in the register of the high descant. This is thus the register of especially high tones, usually on the extreme right side of the piano or grand piano, as viewed by the pianist, and hence also of the resonance board. In FIG. 1, this would be in the vicinity of the second bridge end 24 and less in the region of the sectional line A-A.

(15) In this register of the high descant, the distance between the sound bridge 12 and a bottom support, that is, that edge on which the resonance board 10, in turn, is adhesively bonded, is at a minimum.

(16) There is interest in arranging the point of introduction of energy from the sound bridge 12 into the resonance board 10 as far as possible from the bottom support, that is, to keep it in a region of the resonance board 10 that is as flexible as possible. A similar effect also concerns the bridge for the bass bridge in WO 95/21442 A1 already outlined in the introduction of the description. This goal is attained by way of the region marked with arrow C, where material has been removed.

(17) This is thus an elemental feature of the basic geometry of the sound bridge 12 and the effect of this additional concavity, which runs only over a subregion of the length of the sound bridge 12, may not be altered by the symmetric fillets 20a, 20b.

(18) In the range of the middle and moderately high tones, that is, in the tenor range and not-too-high descant, and also in the range of the strings that represent the moderately deep tones and are still carried on the sound bridge and not on the bass bridge, this concavity is therefore not present. Consequently, the fillets 20a and 20b according to the invention are the sole cutouts in the two longitudinal faces 13 * and 13b of the sound bridge 12, at least in this portion of the sound bridge 12 located in FIG. 1 on the left or in the middle of the resonance board 10. sic; longitudinal faces 13a?Translator's Note

(19) The exemplary embodiments are described only by way of example and may be modified or combined with one another in diverse ways. Thus, the following, in particular, is possible: The fillets 20a and 20b may have any other cross section instead of a cross section resembling the arc of a circle, such as an elliptical cross section, a rectangular cross section, or the like. It is also possible to arrange more than one fillet 20 on each of the bridge sides.

LIST OF REFERENCE SYMBOLS

(20) 10 resonance board 12 sound bridge 13a first longitudinal face of the sound bridge 13b second longitudinal face of the sound bridge 14 bridge cap 16 bridge peg 20a, b fillets 21 vertical axis of the sound bridge 22 first bridge end 24 second bridge end r radius of the fillets a depth of penetration of the fillets b vertical extension of the fillets c distance of the fillets from the top bridge edge d distance of the fillets from the bridge end A-A sectional line (for FIG. 2) B arrows C arrow or concavity