Music – Instruments – Stringed
Reexamination Certificate
2000-12-18
2002-04-09
Hsieh, Shih-Yung (Department: 2837)
Music
Instruments
Stringed
82
Reexamination Certificate
active
06369306
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the field of stringed musical instruments of the guitar and bass guitar family, and more particularly it relates to improvements in the structure of frets, Fret Rods ®, and associated mounting provisions in the neck/fingerboard.
BACKGROUND OF THE INVENTION
Typically a stringed instrument has a neck portion of which one side, herein assumed to be facing upwardly, provides a playing surface known as a fingerboard, above which stretched strings are closely positioned so that a player can set the pitch of a string to a desired note by finger-pressing the string against the fingerboard surface at a corresponding position, thus presetting the length of the vibrating portion of the string and accordingly presetting the frequency of the note then played.
The fingerboard may be made integrally with the neck, typically made of hardwood, or it may be made from a different hardwood or other material and laminated onto the neck. The fingerboard surface may be substantially flat or slightly convex-shaped in cross-section.
Typically fingerboards of instruments in the violin family are made fretless while fingerboards of instruments in the lute family, which includes guitars and bass guitars, are usually fitted with a set of transverse metal frets spaced to provide semitone pitch intervals along the fingerboard. A fingerboard fitted with frets is known as a fretboard.
Usually, the fretboard is finger-stopped with the left hand while the right hand picks, strums and/or plucks the strings; however a special member of the lute family, known as a Stick (R) fretboard tapping instrument, is intended to be played with a technique created by the present inventor in which both hands address the fretboard from opposite sides with all eight fingers oriented at right angles to the fretboard, initiating each note by tapping a string against a fret and holding it there for the desired note duration.
In the lute family, generally, apart from open string notes, the pitch of each note played is set by a string being pressed against the upward extremity, i.e. the fret tip, of a selected fret.
The structure of frets and the system by which they are fastened to the neck/fingerboard to form a fretboard are critical with regard to at least seven parameters:
(1) the actual performance of music, related to fret tip shape and overall uniform accurate alignment of the fret tips in a flat plane close to the strings;
(2) the feel of the instrument to the player, particularly to the fingers: the particular cross-sectional shape of the exposed portion of the frets above the fretboard can be felt by the player's fingers as they move along the strings past the frets in forming notes and expressive nuances, and thus this shape contributes strongly to the overall “feel” of the instrument, which is of great importance to the player;
(3) the aesthetics and general appearance of the instrument;
(4) the producibility including the relative difficulty of assembly and more particularly the effort and time required to level the frets and dress them individually to a satisfactory level of quality;
(5) the long term reliability, including stability and durability, e.g. retention of the frets properly in place over a period of years, and wear along the fret tips;
(6) the maintainability, including the capability and ease of field refurbishment, adjustment and/or replacement of the frets; and
(7) overall cost to produce.
DISCUSSION OF KNOWN ART
FIGS. 1A-1H
show a cross-section of a portion of a neck/fingerboard
10
of a stringed musical instrument fitted with frets of known art having various cross-sectional shapes.
FIG. 1A
shows a fret
12
A configured with a widely-used conventional cross-sectional shape found in a great majority of known art. This generally T-shaped cross-sectional shape provides a mounting tine extending downwardly by which the fret
12
A is retained in a mounting channel with parallel sidewalls sawed transversely across the neck/fingerboard
10
. In original assembly or replacement, the fret
12
A is hammered into place, forcing the tine downwardly into the channel between the parallel vertical sidewalls. Typically the tine is made with small barbs on the sides near the bottom end as shown to assist retention.
The neck/fingerboard
10
is typically made of hardwood in quality instruments, and conventional frets
12
A are typically made a soft malleable metal alloy such as German silver.
An example of such fret structure is found in U.S. Pat. No. 5,952,593 (FIG.
1
A).
Such fret structure and mounting between parallel channel sidewalls fails to provide sufficient positive constraint to hold the fret
12
A in place in the neck/fingerboard
10
: instead, even with the barbs, the retention of the fret depends on friction deriving from the accuracy of a tight fit, which is subject to manufacturing tolerances and/or aging of the wood. Thus there is an inherent risk, borne out by actual experience, that in time, as the wood in the neck/fingerboard relaxes slightly, the frets can become loose and work upwardly out of place. This problem has been addressed by the use of adhesives and/or the addition of barbs on the tine portion in effort to improve the retention and the lifetime reliability.
The conventional cross-sectional shape of the upper exposed portion of the fret
12
A has evolved to the convex top curvature shown, as part of the conventional overall fret structure and mounting system that has become commercially accepted as a practical tradeoff between the seven parameters described above.
Typically, there is deterioration of the frets after a certain amount of playing: the soft frets wear unevenly along the tip as a result of various expressive fingering techniques such as sliding up and down the fretboard and pitch bending by stretching strings sideways along the frets. This unevenness can be accommodated to some extent by resetting the action higher, i.e. relocating the strings further away from the fretboard: however this makes fingering and two-handed string tapping more difficult. Properly reconditioning the instrument for worn frets involves sanding and/or filing the frets down for overall leveling uniformity and, in a luthier's operation known as crowning, re-rounding them as required to restore the original uniform playing action along the fretboard. Frets that are excessively worn or that have worked loose may have to be removed and replaced with new frets that, when installed, will need to be individually dressed.
FIG. 1B
depicts a cylindrically-shaped fret
12
B fitted into a channel of U-shaped cross-section machined into the neck/fingerboard
10
to provide an exposed arc that corresponds to the exposed fret portion shown in
FIG. 1A
, and can be inserted downwardly between the parallel portion of the channel sidewalls. An example of the structure shown in
FIG. 1B
is found in U.S. Pat. No. 4,633,754, granted to Chapman, the present inventor, wherein retention is provided by adhesive in the side gaps in the upper region of the U-shaped channel.
FIG. 1C
depicts a cylindrical fret
12
C that fits closely into a channel with a cross-section that has no parallel sidewalls; instead it is circular with a gap opening at the top that exposes the exposed arched portion of the fret
12
C, which must be inserted endwise into the channel, providing positive fret retention against vertical shifting. Examples of such structure are found in U.S. Pat. No. 3,712,952 (
FIG. 2
) to Terlinde, British patent 1,394,346 (
FIG. 2
) to Wood, and in German patent 2,553,563 (
FIG. 3
) to Kist.
FIG. 1D
depicts a version of
FIG. 1C
with the cylindrical fret
12
D retained by flanking inter-fret spacers
10
A that form a fingerboard surface layer attached onto neck
10
, as in U.S. Pat. No. 4,633,754 by the present inventor.
FIG. 1E
depicts a hollow tubular fret
12
E in a close-fitting channel formed between inter-fret surface blocks
10
A′ and retained by a screw traversing a full length support panel
10
B fastened onto the main wooden portion of
Hsieh Shih-Yung
McTaggart J. E.
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