US 2208391 A
Description (OCR text may contain errors)
y 15, 1940- M. RWEFEA STRING INSTRUMENT Filed July 27, 1959 Patented July 16, 1940 UNITED STATES PATENT OFFICE STRING INSTRUMENT Application July 2'7, 1939, Serial No. 236,741
This invention relates to improvements in string instruments, and particularly to the bridge construction for the tops or sound boards of the instruments. It is specifically described in con- '5.. neotion with a guitar although it should be understood that the invention is not to be considered limited to instruments the strings of which have to be plucked. v
It is an object of the invention to attain greater beauty and fullness of tone by inducing vibration of the sound board in a different and amplified degree compared with that vibration which is induced in guitars of the known construction.
The invention also has the object of providing a guitar in which the number of frets is increased over the number of frets (usually 12 frets) with which the standard guitar is equipped, thereby increasing the playing range of the instrument.
The invention also has the object of providing an instrument having greater resonance than the instruments heretofore known and in general use.
With these and numerous other objects in view, an embodiment of the invention is described by way of example in the following specification in which reference is made to the accompanying drawing. 7
In the drawing:
Fig. 1 is a front elevation of the improved guitar:
Fig. 2 is a side elevation of the same.
The guitar has the usual body with a bottom I, the side 2, and the top 3, which latter constitutes the sound board of the instrument. The body of the instrument slightly higher at the lower end than at the upper end is supplemented by a neck 4 directly secured thereto and provided with the usual keys 5 through which the strings 6 may be adjustably tensioned as required.
The strings 6 (of which six are shown as in the standard guitar) extend from these tensioning keys or pegs over the frets l on the neck and over a sound hole Sin the top or sound board 3 of the body. They are secured at their ends to a bridge 9 which is firmly located on top of the sound board; as for instance, it is advisably fixed in position by glue or in some other suitable way.
The bridge 9 in the present invention is shown as being disposed at that point of the sound board or top 3, at which the vibrations have their maximum amplitude.
The body of the instrument itself may be reinforced in the usual way. For this purpose, ribs Ill fastened to the under face of the sound board extend radially, so that their prolongation would intersect the medial plane of the board at a point on the edge of the sound board. These ribs shown in dotted lines, however, do not extend over the full length of the board, but terminate adjacent a transverse rib l I which also is secured to the lower face of the board 3 slightly spaced from the sound hole ii. A further reinforcement rib H extending transversely on the under face of the board also arranged at the opposite side of the sound hole 8 and at approximately the same distance from it as rib l I.
The bottom of the body also may be provided with transverse reinforcing ribs, and the side or circumferential wall of the body may have posts, not shown. This circumferential wall may be united with the top and the bottom respectively 10 by strips (not shown) along the inner face of the wall 2 at its top and bottom edge, and glued to the instrument.
, The above construction furnishes a sound board, as it is usually employed in guitars of the 15 Spanish type. Owing to the provision of the transverse rib ii, the part of the sound board secured to this rib forms a nodal point for the vibrations of the board, the vibrations having the maximum amplitude at a point which is approxi- 20 mately centrally of the area of the board confined by the rib l I and the circumferential edge, namelythe area beneath which the radial ribs it are applied.
But while the construction here shown illus 5 trates the Spanish type of guitar, the invention is equally applicable to the so-called American type guitars.
It is at the point of maximum amplitude of vibrations hereinafter called the focus of vibra- 30 tions at which the bridge Q is located.
In the Spanish guitar, as known in the prior art, the lower ends of the strings are secured to a bridge which is directly glued to the top of the body. In the American type guitar which is dis- 35 tinguished from the Spanish guitar by different bracing, the lower ends of the strings also may be secured to a bridge as in the Spanish guitar, or they are secured to an anchor piece which in its turnis fastened to the circumferential wall of the 40 body, preferably at a. point in opposition to that circumferential point of the body from which the neck of the instrument extends. The lower anchoring elementin American guitarstherefore, corresponds to that anchoring element which is in 5 general use on violins and other string instruments to be played with the bow.
The present invention is distinguished from the manner of attaching the strings, as known in either type of guitar, by the fact that the lower ends only of the strings 6 are secured to a bridge 9 fastened to the top 3 of the body at the focus of vibrations; the strings intermediate this anchoring bridge 9 and the pegs 5 are tensioned and syntonized over an auxiliary bridge I2 which is located between the main anchoring bridge 6 and the sound hole 8.
The Spanish guitar usually is provided with twelve frets on the neck between the head and body. Owing to the selection of an auxiliary 5O bridge 12 spaced from the focus of vibrations the guitar may be built with fourteen frets or more on the neck, while still retaining the location of the main bridge in the usual position. By providing anadditional bridge l2, closer to the syntonization knob [5 on the head, it will now also be feasible to increase the number of frets on the fingerboard l6 extending the additional frets downward over the body of the instrument and the neck extension. The number of frets, for instance, may be increased to fifteen, sixteen, or even seventeen. The length of neck on which these additional frets are provided is in predetermined relation to the distance between the auxiliary bridge [2 from the main bridge 9. Proper spacing of the auxiliary bridge I2 from the main bridge will lead to complete syntonization of the notes of the scale.
The anchoring bridge 9 is shown to be provided with a raised extension I4 wherein,-in the embodiment illustrated, the ends of the strings 6 are tied by knots. It is obvious, however, that anchorage by pegs or the like as it is known from the standard practice, may be provided.
The Spanish guitar usually is provided with twelve frets on the neck between the head and body. By positioning the additional bridge l2 closer to the syntonizing knob E5 on the head, the number of frets on the neck of the same length may be increased. Owing to this reduction of the space occupied by the individual frets, the fingerboard l6 forming the extension of the neck above the upper portion of the sound board will then be also adapted to receive a greater number of frets of progressively reduced width. In this manner the playing range of the guitar may be increased from approximately an octave and a half to two octaves since as many as twenty-four frets can be positioned on the same length of neck and fingerboard which up to now received as a rule eighteen or nineteen frets.
The player, therefore, may play on these frets from the twelfth to the fifteenth over the neck of the guitar away from the top thereof, and
higher frets may be within the shortest reach so thatin spite of the increase of the playing range to two octaves, the performance on the instrument is greatly facilitated.
In the playing of the instrument, it has, however, been discovered that owing to the application of the pull on the sound board in the focus of vibrations, as in the standard guitar, and the application of the tensioning and syntonizing element at a distance from said focus of vibration, the fullness of the sound, the beauty of the tone and the responsiveness of the instrument are greatly enhanced. The provision of the auxiliary bridge at a distance from the focus of vibrations is of extremely beneficial eifect on the instrument.
The auxiliary bridge may adjustably rest on the top of the sound board 3, for which purpose it may be provided with a plurality of short base portions or feed. Like other bridges on string instruments, it tapers in cross-section from the narrow tip towards the wider base to facilitate syntonization of the instrument. While the aux iliary bridge l2 also may be glued to the sound board 3 of the instrument like the main bridge 9, it is obvious that this auxiliary bridge is adapted to be held in its operative position solely by the pressure of the strings placed thereon.
I am aware of the fact that it has been proposed to secure the strings of the instrument by pegs to the top of the body, and to provide a top would not be interfered with in any way by the hands when playing. It was also believed that in this manner the vibration of the strings would be directly transmitted to the sound board without dissipating any energy of vibration through contact with the body. In the present arrangement, the strings are anchored at their ends of the sound board, but are additionally tensoned over a bridge fixedly located, though it may be adjustable, on the sound board itself, exerting thereby a double influence upon the sound board and modifying the vibrations of the latter to great advantage.
1. In an instrument of the character described, the combination of a body having a sound board, a neck, a bridge secured to the sound board substantially centrally of the area of vibrations, strings secured at their endsto the bridge and neck respectively, and an additional bridge spaced from the first bridge and resting on the same sound board, both of said bridges being supported on the vibratory sound board exclusively and being adapted to vibrate with the sound board.
2. In an instrument of the character described, the combination of a body having a top, a neck extending from said body and one end thereof, a bridge secured to the top only, strings each attached at one end to the bridge, the other end of each string being adjustably fastened at the neck, and an auxiliary bridge, resting on the top only between the first named bridge and that end of the top from which the neck extends, the strings being tensioned inengagement with the auxiliary bridge, whereby vibrations of the strings are converted into vibrations of the top through both bridges the first named bridge being positioned substantially at that point of the board at which the vibrations have the maximum amplitude the strings being secured at one end to a point which does not vibrate with the sound board while the strings at the other end are secured to the bridge which vibrates with the sound board.
3. In an instrument of the character described, the combination of a body, a sound board on said body, a neck, a bridge secured to said body, strings fastened to the bridge and to the neck, the bridgebeing located in the focus of vibrations produced upon plucking the strings, and a second bridge over which the strings are tensioned and located closer to the neck than the first named bridge.
4. A musical instrument of the string type, comprising a body, a sound board on top of the body, the marginal portions of the sound board being held against vibration by connection of said marginal board at its margins with the body, the remaining portion of the sound board being free to vibrate, a neck extending from said body, a bridge mounted on the sound board in a position to vibrate with the same, strings anchored at one end to the non-vibratory neck and at the other end to the vibratory bridge on the sound board, and a second bridgeinterposed between said first named bridge and the neck over which the strings are tensioned.