Composite structure for a stringed instrument

Description Submit all comments and votes

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention is directed to carbon fiber composite musical instruments.

2. Description of the Prior Art

Traditionally, instruments constructed of wood, have incorporated mechanical means, glues lamination or combinations thereof to affix separate structural pieces together. All of these methods are known to affect the tone of the instrument.

The focus in composite stringed instrument construction has been to emulate the frequency distribution of traditional wooden instruments while benefiting from the structural stability of composite materials, efficient production methods of molded construction, or both.

Composite construction has primarily utilized carbon fiber as the resin reinforcement fiber of choice, largely due to the high strength to weight ratio, the high modulus of elasticity and the low coefficient of thermal expansion. It is known that continuous carbon fibers are stronger and more durable than the bonds of glue, lamination, integrally molded dissimilar materials, a resin matrix without reinforcement of continuous fibers, and of mechanical means of affixation. Also, continuous fibers conduct energy to a higher degree than an abrupted medium, and thus both energy reflection and dissipation decrease accordingly.

A problem with achieving the ideal traditional sound of wood with a carbon fiber reinforced resin matrix is partially due to the relatively lower degree of energy absorption. The lower degree of energy absorption is desirable for sustain qualities and harmonic clarity yet it is undesirable due to the relative excess in high frequencies. This characteristic has been addressed by utilizing dampening materials such as cardboard, wood, and aramid to lower the ratio of high to low frequencies and to conduct force with respect to auditory dispersion in a manner closer to the traditionally preferred wood.

Additional factors affecting tone quality in composite construction are resin to fiber ratio, fiber orientation, resin type, resin cure temperature, preload fiber tension, fiber modulus of elasticity, area and unit density, as well as, a multitude of structural functions.

Some prior art has eliminated the use of wood due to inevitable structural variabilities and inconsistencies Thermal expansion and contraction as well as long term structural changes, such as creep and drying, also affect tone and strength. These variances when integrated with dissimilar materials can also bring rise to delamination or other structural failure.

It is common for the shape of composite acoustic guitars to replicate the traditional acoustic guitar shape. A standard shaped guitar includes an increase of the depth under the fretboard at the junction of the acoustic chamber with the heal of the neck which is approximately at the 14th fret This limits the access of the upper register, the 12th to a possible 24th fret, as it overlaps the sound chamber. The introduction of the "cutaway", a removal of the sound chamber portion adjoining the overlap, has improved access of the upper register, yet the neck design has remained unchanged The traditional increase in depth under the playing surface with a heal at the junction of the body has remained a constant. Thus, the heal and the acoustic chamber integral to the underside of the playing surface mandate a varied playing form in the transition from the lower register to the upper register.

Traditional acoustic guitar bracing provides soundboard reinforcement for string tension support. The braces are generally lengths of wood glued to the underside of the soundboard in a diverse variety of patterns. In the construct of an arch top guitar, a tailpiece is additionally implemented. Traditional violin construct, typically provides string tension support by means of a length of wood glued to the underside of the upper soundboard along the longitudinal axis relative to the bridge, a tailpiece, a bridge, and a sound post. Additional strength is inherent in the curvature and varied thickness of the soundboards. Composite acoustic construction has emulated the traditional processes.

A primary objective of the present invention is to provide a composite structure for use as a stringed instrument neck and body formed of a cast of a fiber reinforced single resin matrix including means for attaching tuning keys, a nut, a fretboard, amplification means, and a bridge.

Another objective of the present invention is to provide a composite structure for an acoustic guitar, wherein access is provided to the upper register, unobstructed by a heal or an acoustic chamber of traditional form as the acoustic chamber is not integral to the region below the playing surface.

Still, another objective of the present invention is to provide a composite guitar having a neck and body structure which includes a plurality of integral tubes and having a fiber orientation of two or more helically wound tubes integral within a helically wound tube.

SUMMARY OF THE INVENTION

In accordance with the present invention is provided a composite structure for use as a stringed instrument neck and body formed of a cast of a fiber reinforced single resin matrix. Provided by the structure are means for attaching tuning keys, a nut, a fretboard, amplification means, and a bridge.

In accordance with the present invention is provided a composite structure for an acoustic guitar, wherein the acoustic chamber is not integral to the region below the playing surface such that the neck does not increase in overall depth until the end of the playing surface. Thus, access is provided to the upper register, unobstructed by a heal or an acoustic chamber of traditional form.

Also provided, in accordance with the present invention is the structure of a single resin matrix encapsulating continuous longitudinal fibers which extend distal to the bridge and nut, which encircle the periphery of the neck, which intermediately connect the peripheral matrix, and those which surround the longitudinal fibers integral with the body of the instrument.

Additionally there is provided a neck and body structure for a composite guitar incorporating a plurality of integral tubes. Further provided, is a fiber orientation of two or more helically wound tubes integral within a subsequently wound helical tube. Inherent of this form are continuous fibers which extend distal to the nut and the bridge, as well as, interconnect the peripheral orientation intermediately.

In accordance with the present invention is provided a soundboard brace for use as an internal tension support element in the construction of an acoustic guitar, which contacts the underside of the soundboard at an area relative to the bridge and extends to one or more points of the body, the apposing soundboard, or both. And preferably utilizing the sidewall for longitudinal support and the apposing soundboard for lateral support.

In accordance with the invention is provided an integral soundboard, bridge, and brace structure cast of a fiber reinforced single resin matrix, for use as an amplification, string alignment, and string tension support element of an acoustic guitar. Preferably a planar form of a soundboard of carbon fiber is layered or commingled with aramid as well as an integrally molded continuous fiber brace which passes through the planar layer to the form of the bridge.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of an acoustic guitar in accordance with the invention;

FIG. 2 is a partial side cross view in accordance with the present invention;

FIG. 3 is a perspective view of a lower medial acoustic plural tube;

FIG. 4 is a cross sectional view of a head;

FIG. 5 is a cross sectional view of a neck along line 5--5 of FIG. 1;

FIG. 6 is a cross sectional view of a plural tube neck taken along line 6--6 of FIG. 1;

FIG. 7 is a cross sectional view of a subsoundboard brace structure;

FIG. 8 is a bottom view of a subsoundboard brace structure;

FIG. 9 is a cross section of a plural tube at a tube neck;

FIG. 10 is a side sectional view of an acoustic peripheral plural tube;

FIG. 11 is a perspective top view of a peripheral acoustic plural tube;

FIG. 12 is a telescoped perspective cross section of a plural tube structure; and

FIG. 13 is an exploded view of a core for a composite structure oriented for electrical amplification.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

Referring initially to FIGS. 1 and 2, an acoustic guitar in accordance with the present invention is shown at 10. The guitar has an integral neck 12 and body 14 cast of a fibe