Patent Abstract:
A stringed musical instrument or guitar has a plastic foam body substantially covered by a shell of thermoplastic material, a wood base on the plastic foam body, a plurality of strings supported to extend above the wood base, and at least one electromagnetic pick-up at the base. Musical vibrations produced by strumming the strings are conducted via the plastic foam body and wood base are largely sensed by the electromagnetic pick-up.

Full Description:
RELATED APPLICATIONS 
     Reference is made to my Provisional Application No. 60/167,376, filed Nov. 24, 1999, entitled “Guitar”. 
    
    
     BACKGROUND AND SUMMARY OF THE INVENTION 
     Desirable characteristics for stringed instruments, such as base viols, cellos, guitars, and violins, etc., include the provision of sharp, clear tones, and substantial resonance. 
     Prior art guitars often do not produce such tones, and typically have resonance periods of only about 8 seconds. 
     The present invention provides a guitar having a polyurethane foam body and an interfitting hardwood base member, with a sound reservoir defined by a cavity in a hardwood member wherein a foam core is disposed, in which electromagnetic pick-ups are disposed. 
     The entire guitar is encased in a fiberglass shell, except for the sound reservoir, wherein the pick-ups are disposed. Resonance of about 28 seconds is produced. Substantially all musical notes produced by the strumming of the strings of the guitar are conducted via the hardwood and polyurethane foam components to exit the guitar via the sound reservoir. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a top view of a guitar according to the invention; 
     FIG. 2 is a bottom view of a body portion of the guitar of FIG. 1; 
     FIG. 3 is a perspective view of the guitar body of FIG. 2, showing the top of the body prior to assembly of operating components; 
     FIG. 4 is a sectional view taken at line  4 — 4  in FIG. 1; 
     FIG. 5 is an exploded perspective view showing a foam insert of FIGS. 3 and 4 in relation to a hardwood base member; and 
     FIG. 6 is a perspective top view of a modified embodiment of the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention relates generally to stringed musical instruments, and in particular to guitar structures. 
     Referring to the drawings, a preferred embodiment  10  of the invention comprises a hardwood base member  12 , preferably of mahogany, and a foam body  14 , typically of high density closed cell polyurethane foam. As shown, hardwood base member  12  is interfitted with the foam body  14 , in which a rectilinear cavity  16  is defined and which comprises a sound reservoir or resonator bay  18 , wherein a core  20  of polyurethane foam is disposed. Although shown as rectilinear, the sound reservoir may be of different configurations, such as oval, circular, etc. 
     Defined in the foam body  14  are cavities to accommodate electronic components and connectors (not shown), a generally oval cavity  22  containing conventional three-way switch equipment (not shown), and a tear-shaped larger cavity  24  accommodating electronic components and connectors (not shown). The components in these cavities are preferably encased in polyester resin or the like. 
     Electromagnetic pick-ups  26 ,  28  are disposed in cavities in foam core  20  in the sound reservoir  18 . Each pick-up has a casing thereabout. The pick-ups extend preferably about three-quarters the depth of the foam core  20 . A plurality of pick-ups may be provided in each cavity (not shown), and various combinations of respective pick-up types may be utilized. 
     The pick-ups are covered by bezels  31 ,  33  to which they are connected. The bezels are mounted by threaded fasteners, and certain threaded fasteners (not shown) are rotatable for raising and lowering the pick-ups  26 ,  28  to provide desired sound effects. 
     The guitar is substantially entirely sealed, except for the sound reservoir  18 , by being wrapped in fiberglass  29  (FIG.  4 ), typically fiberglass cloth or matting of preferably 3 oz. to 12 oz. weight. Carbon fiber or Kevlar might be utilized. 
     The sound reservoir is an important feature of the present invention. The guitar foam body being encased in a fiberglass shell, except for the sound reservoir, musical sounds and notes, cannot escape the guitar except by passing through the sound reservoir. 
     When the guitar strings  34  are strummed at neck  36 , the musical tones produced pass via the bridge  30  and tail piece  32  into the hardwood base member  12 , and thence to the foam care  14  in the sound reservoir, and to the pick-ups. The musical sounds have essentially no exit from the guitar except via the sound reservoir and the pick-ups. All other areas or exits are sealed and closed by the fiberglass shell  29 . 
     The polyester foam body  14  is secured to the interfitting hardwood base member  12  by a hard adhesive, because a soft adhesive would absorb musical sounds, and it is desired to provide as brittle musical tones as possible. The surfaces of the polyester foam are not coated with adhesive or other coating. 
     The fiberglass shell  29  provides strength, rigidity, and also provides clear, high-end frequency, bright tones. The hardwood base member  12  provides rich, dark tones, or bottom end bass tones. 
     The foam components typically of 4-8 lb. density, provide sustained resonance and a resonant quality whereby each note reverberates for a substantial period of time, without electrical amplification, thus to provide increased duration of resonance. 
     It is believed that the cumulative effect of the vast number of foam cells, expanding and contracting somewhat in the manner of miniature diaphragms, generate tiny audible pulses in response to musical vibrations. The cells are closed-cell foam plastic, preferably polyurethane foam, and vibrations or air pressure waves pass from one closed cell to adjacent closed cells via cell walls. The cumulative effect is to produce resonant, audible output via the pick-up devices, air trapped in the cells of the plastic foam being alternately pressurized and depressurized in accordance with musical tones and notes generated, according to the invention. The foam body typically has a density of 4-8 lbs. to provide sustained resonance and a resonant quality, whereby each note vibrates for a substantial time period without electrical amplification. 
     FIG. 6 illustrates a modified form of the invention wherein a wood base member  40  has defined therein two cavities  42 ,  44  wherein electromagnetic pick-ups or transducers are mounted (not shown). No foam member is provided in either cavity, and the pick-ups or transducers are in direct contact with wood base member  40 . Musical notes are transmitted through the foam body and the wood to the pick-up transducers. 
     It will be understood that various changes and modifications may be made from the preferred embodiment discussed above without departing from the scope of the present invention, which is established by the following claims and equivalents thereof.

Technology Classification (CPC): 6