Music – Instruments – Stringed
Reexamination Certificate
2000-10-30
2002-10-08
Nappi, Robert E. (Department: 2837)
Music
Instruments
Stringed
C084S31400N
Reexamination Certificate
active
06462259
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the field of musical instruments, and more particularly, in the field of stringed musical instruments it relates to improved structure in a nut assembly for string support that provides adjustment for string clearance to satisfy the string setup demands of the conventional guitar family as well as the more exacting demands of instruments designed to be played with a two-handed string-tapping technique. such as The Chapman Stick.
BACKGROUND OF THE INVENTION
In stringed instruments such as guitars, typically a neck portion including a fingerboard, extends from a body portion to an integral headstock which carries tuning pegs and their mechanisms. The strings are stretched over two basic support points; the first known as the bridge, located in the body region, and the second known as the nut, located between the fingerboard and the headstock. The distance between these two support points, in conjunction with the string tension and mass, determines the vibrational resonant frequency and thus the musical pitch of an open string.
The player can increase the pitch by stopping the string, i.e. pressing it against the fingerboard, which may be smooth and fretless as in a violin, but more commonly in the lute/guitar family, made as a fretboard with transverse frets spaced to form the chromatic musical scale. To raise the pitch a semitone from open tuning the player finger-stops the string at the first fret by placing a finger on the string between the nut and the first fret and pressing it against the fret, thus moving the second support point closer to the bridge, which remains fixed as the primary support point. This shortens the vibrational string length and increases the pitch a semitone higher than the open string pitch. The player then plays the note by picking, plucking or strumming the string with the other hand with a velocity that determines the initial amplitude and loudness, then the note rings with diminishing amplitude until it dies out at the end of the sustain time.
In the case of tapping technique, by quickly and cleanly pressing a string against a fret and holding it there: the burst of energy imparted as momentum by the velocity of the initial displacement becomes converted to vibrational energy that determines the initial amplitude and loudness, then, as in conventional technique, the note rings with diminishing amplitude until it dies out at the end of the sustain time. Since the tapping technique eliminates the need to pick, pluck or strum the strings, both hands can be dedicated to playing notes on the fretboard, more strings can be utilized, typically eight, ten or twelve, and thus the player's versatility and virtuosity are potentially doubled. For the tapping technique the demands for accurate string-to-fret spacing are more exacting, therefore, prior to the present invention, all Chapman Stick instruments were made with individual string height adjustments at the nut.
Conventional fretboards are typically made with a transverse convex curvature, while the Chapman stick is made flat; in either case each fret is made to be constant in height above the fingerboard. The two string support points are initially set up for height to provide a desired “action” as determined by the spacing between the bottoms of the strings and the tops of the frets. This is usually made different for different string sizes, and is usually set as low as possible for ease of playing, while avoiding any buzzing due to vibrating strings coming into contact with higher frets. There is almost always a succession of strings of different diameters, which all need to be accurately spaced from the frets for optimal overall playing action, for which both the bridge and the nut must be set accurately.
The bridge establishes the height and inter-string spacing at the first support point, which principally determines the action over the entire fretboard. When a string is finger-stopped at any fret, the bridge height for that string sets the fret-to-string clearance at all higher frets, and since these all face the vibrating portion of the string, they require sufficient clearance. In many guitars the bridge height is adjustable by rotating a pair of thumb-finger screw adjustment wheels, one at each end of the bridge. In some professional-quality guitars and in all models of the Chapman Stick, the bridge is equipped with individual height adjustments for each string.
At the other support point, in both conventional guitars and tapping type instruments the height of the nut support point also affects the overall action importantly, since it affects the amount of string displacement required to finger-stop or to tap a string at a fret, particularly toward the nut end. However, the string-to-fret clearances are affected by nut height only when the string is played open: with a string finger-stopped at a fret, clearance for the vibrating string portion depends entirely on the bridge height. Thus a guitar requires the nut to made high enough to prevent vibrating string contact with any fret, particularly the first fret.
A higher action setting makes finger-stopping and tapping more difficult due to the geometrically required stretching and vertical bending of the strings, particularly at the first fret.
With the string-tapping technique, open strings are normally not played, and generally the maximum vibration amplitude is smaller on all strings than with conventional guitar playing techniques. Thus, for tapping-type instruments, it has been found possible and desirable to set up the instrument for much lower action: in particular the nut can be set to make the first fret-to-string spacing much closer on all strings, which greatly enhances the ease of playing with the tapping technique, particularly at the first and lower frets.
Typically the guitar nut is made from a hard material such plastic, bone or metal, and is placed in a fixed location, typically held with adhesive, providing only a general purpose string height setting that is not user-adjustable.
The nut is typically configured on top with a series of notches known as saddles, one for each string, that function to constrain the strings laterally, to keep them spaced apart uniformly, and to support them at the correct height above the first fret to set the desired string-to-fret clearances.
A greater clearance must be set between the bottoms of the strings and the tip of first fret for larger strings due to their increased vibrational excursions. The strings typically vary in diameter, ranging in a sequence from thinnest to thickest along the fret to provide a single tuning group.
On guitars, the saddle notches are usually saw-cut to be approximately rectangular in cross-section; they may be made different in width to laterally constrain different sized strings and different in depth for different fret clearances requirements of different sized strings. These variations are difficult to standardize, and restrictive with regard to altered tunings and/or string gauges, leading to substantial burdens, problems and costs in original manufacture, field use, maintenance and repair, often requiring costly, tedious sawing and filing operations that must be performed manually on individual saddle notches by skilled technicians attempting to obtain optimal playing action. Excessive sawing or filing can destroy the nut due to loss of sufficient string clearance at the first fret, and the nut would then have to be removed and replaced with a new one.
Despite these shortcomings, the conventional fixed nut system is considered to be cost-effective and generally satisfactory for many basic conventional stringed instruments with only four or six strings in a single tuning group. However, it may become troublesome in instruments with eight or more strings, particularly if the strings are arranged in two or more tuning groups. For example, in The Chapman Stick, standard models have ten strings divided into two tuning groups of five; very low playing action, i.e. close string-to-fret spacing, is partic
Lockett Kim
McTaggart J. E.
Nappi Robert E.
LandOfFree
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