Abstract:
An acoustic guitar assembly having a support system consisting of a novel shaped neck block, graphite rods and graphite ribs. The ribs are epoxied to the underside of the soundboard and originate in close proximity to one another adjacent to the neck block and fan out from there to positions along the bottom of the soundboard. The rods run from the neck into the head block and support the neck joint. The guitar has two sound holes positioned near the top of the soundboard.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to an acoustic guitar, and more particularly to an acoustic guitar with a unique bracing system.  
           [0003]    2. Description of Related Art  
           [0004]    Strumming the strings of an acoustic guitar produces sound not only from the vibration of the strings, but also from the transference of those vibrations through the guitar&#39;s bridge into the soundboard. The soundboard, which is essentially a vibrating plate, has its own limitations on natural vibrating frequencies and careful design is therefore required in order to achieve the desired frequency response. Essentially, the more freely the soundboard can vibrate, the better the tone and sustain of the guitar. Unfortunately, the soundboard must be strong enough to support the tension created by the guitar strings, and some of the best soundboards are not able to support that tension without some type of support. Historically this support has come from attaching supportive bracing to the underside of the soundboard.  
           [0005]    Soundboard bracing is often complex, difficult to construct, expensive to produce, and highly restrictive to the soundboard. For example, U.S. Pat. No. 4,056,034 to Kaman discloses a guitar in which the tension forces in the strings are reacted through a central portion of the bout where the single conventional sound hole is normally provided. The sound holes are located in the upper bout. The &#39;034 patent can be differentiated from the present invention because the tension reacting forces of the present invention consist of graphite ribs that are curved rather than straight and extend from the bottom to the neck of the guitar. The present invention also has a reinforced neck and novel neck block.  
           [0006]    U.S. Pat. No. 4,079,654 to Kasha discloses a bracing system for a guitar-type stringed instrument using a plurality of multidirectional braces attached to the underside of a soundboard. The &#39;654 patent can be differentiated from the present invention in that the present invention uses a fewer number of longer curved graphite ribs which extend from the base of the guitar to the neck block. The &#39;654 patent also does not disclose a flared neck block.  
           [0007]    U.S. Pat. Nos. 5,461,958 and 5,952,592 disclose acoustic guitar assemblies having a bracing on the underside of the soundboard that surrounds a centrally located sound hole. The &#39;958 and &#39;592 patents can be distinguished from the present invention because they lack curved braces which travel from the guitar base to the neck block and they disclose centrally located sound holes which are not included in the present invention.  
           [0008]    A second problem with prior art guitar designs is that guitar neck joints and necks are not strong enough to resist the tension created by the strings. Over time the guitar develops a warped neck or breaks at the neck joint, which is often a dovetail joint.  
           [0009]    An example of a prior art solution to the above problems can be found in U.S. Pat. No. 4,172,405, which discloses a guitar neck that is stiffened by an adjustable rod and a rearward extending heel that connects to the guitar body. The &#39;405 patent is distinguishable from the present invention in that the present invention includes varying lengths of graphite rods to stiffen the guitar neck as well as a traditional truss rod. The neck of the present invention is also butted directly against the neck block and epoxied, unlike traditional guitar assembly.  
           [0010]    None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.  
         SUMMARY OF THE INVENTION  
         [0011]    The acoustic guitar assembly is a guitar with a novel bracing system that enhances guitar tone and sustain as well as durability. The guitar assembly has a traditional soundboard with an external surface, internal surface, a top, a bottom, a left side and a right side. The soundboard is supported on its internal surface by a bracing assembly including a plurality of individual ribs. The ribs originate in a central position a few inches from the top of the soundboard and fan out into positions along the bottom end of the soundboard. There are two sound holes defined in the soundboard, one located on each side of the top of the soundboard.  
           [0012]    The invention also includes a novel neck block. The neck block has flared top and bottom portions, and a constricted central portion. Viewed from above or below, the neck block has two parallel edges, one longer than the other. The, parallel edges are connected by two arching edges. The neck block supports the neck, soundboard and backboard of the guitar.  
           [0013]    The guitar neck is strengthened by four graphite rods. A traditional truss rod runs down the center of the neck and the graphite rods are paired on each side of the truss rod. The rods abut a novel graphite support plate at the bottom of the neck. The support plate is rectangular, is approximately the width of the neck, and is glued to the soundboard.  
           [0014]    Accordingly, it is a principal object of the invention to provide an acoustic guitar assembly that produces superior sound quality.  
           [0015]    It is another object of the invention to provide an acoustic guitar assembly of high strength.  
           [0016]    It is a further object of the invention to provide an acoustic guitar assembly that is resistant to warping.  
           [0017]    Still another object of the invention is to provide an acoustic guitar assembly that is light in weight.  
           [0018]    It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.  
           [0019]    These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]    [0020]FIG. 1 is a perspective view of an acoustic guitar assembly according to the present invention, the strings being fragmented to show the neck and upper body.  
         [0021]    [0021]FIG. 2A is an elevational view of the front surface of a soundboard.  
         [0022]    [0022]FIG. 2B is an elevational view of the back surface of a soundboard showing the bracing.  
         [0023]    [0023]FIG. 3A is a front view of a neck block constructed according to the present invention.  
         [0024]    [0024]FIG. 3B is a top view of a neck block constructed according to the present invention.  
         [0025]    [0025]FIG. 3C is a side view of a neck block constructed according to the present invention, viewed in the same position as shown in FIG. 4.  
         [0026]    [0026]FIG. 4 is a fragmented, sectional view of a guitar constructed according to the present invention.  
         [0027]    [0027]FIG. 5 is a diagrammatic view of a guitar constructed according to the present invention illustrating the bracing system. 
     
    
       [0028]    Similar reference characters denote corresponding features consistently throughout the attached drawings.  
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0029]    Referring now to the drawings, FIG. 1 illustrates a guitar  10  constructed according to the present invention. The guitar  10  has hollow body  12  with a soundboard  16  (front surface) and backboard  22  (back surface) connected by a side wall  20 . The sidewall  20  forms the top, bottom, right and left sides of the body  12 . A neck  14  with a top surface, bottom surface and first and second ends is attached by its first end to a neck block  30  (discussed below) located inside the top of the body  12 . The first end is enlarged so as to form a foot  15  that facilitates attachment to the neck block  30 . A head stock  24  is connected to the second end of the neck  14 . A fretted fingerboard  13  is attached to the top surfaces of the neck  14  and the soundboard  16 .  
         [0030]    [0030]FIGS. 2A and 2B detail the front  17  and back  19  surfaces of the soundboard  16 , respectively. The soundboard  16  is preferably made of wood. The soundboard  16  is approximately 0.1 to 0.12 inches thick, and has a top, a bottom, front surface  17 , back surface  19  and two sides. Two generally ovoid holes  18  are defined in the top of the soundboard  16  between the front and back surfaces. The holes  18  allow sound to escape from the body  12 . A tail piece  20  is attached near the bottom of front surface  17 . Guitar strings (not shown) attach to the tail piece  20  at high tension and create stress on the soundboard  16 .  
         [0031]    [0031]FIG. 2B details several ribs  26  which are epoxied to the back surface  19  of the soundboard  16 . The ribs  26  are triangular in cross section, pre-shaped and preferably are made of a graphite core overlaid with spruce. The ribs  26  originate in a central location near the top of the soundboard  16  and fan out to several locations near the bottom of the soundboard  16 . The fan design allows the ribs  26  to brace the soundboard  16  against the stresses caused by vibration of the strings, while at the same time permitting the soundboard  16  to vibrate more freely than traditional bracing designs. The increased vibration contributes to better tone and sustain.  
         [0032]    [0032]FIG. 2B depicts five ribs  26  disposed on the back surface  19  of the soundboard  16 . Other preferred embodiments only require using three ribs  26 . The five rib embodiment is used for folk guitars having steel strings. The three rib embodiment is used on classical guitars with nylon strings. Nylon strings produce less stress on the soundboard  16  than steel strings. Therefore, fewer ribs  26  are required to relieve the stress from the nylon strings.  
         [0033]    [0033]FIG. 3A shows the front surface  32  of the neck block  30 . The neck block  30  is preferably made of a hard wood and has a front surface that is flat with a periphery having one long edge and one short edge that are substantially parallel and which are connected by two arcuate edges. The back surface  34  of the neck block is substantially similar in shape to the front surface  32 .  
         [0034]    [0034]FIG. 3B illustrates a top view of the neck block  30 . From the top the neck block  30  resembles an hourglass in shape with flared top  32  and bottom  32  surfaces constricting to a smaller central area or isthmus.  
         [0035]    [0035]FIG. 3C illustrates a side view of the neck block  30 . From the side view, the neck block  30  has a substantially straight, flat, neck-connecting surface  36  whose front-to-back length is shorter than the top-to-bottom length of either the front surface  32  or the rear surface  34 . Opposite the neck-connecting surface  36  the neck block  30  forms an inwardly sloping arch between the bottom edges of the front  32  and back  34  surfaces.  
         [0036]    [0036]FIG. 4 illustrates a sectional view of a guitar  10  constructed according to the present invention. The neck block  30  is located inside the top of the body  12  with its neck-connecting surface  36  (not labeled) supporting the neck  14 . The front  32  and back  34  surfaces of neck block  30  support the soundboard  16  and the backboard  22 , respectively. The neck block  30  makes the body  12  rigid enough to support the neck  14  against the tension generated by the strings  28  (not shown).  
         [0037]    Conventional guitars use a dovetail joint and glue to secure the guitar neck to the body. These joints are difficult to create and often warp or completely fail over time. Unlike conventional guitars, the neck  14  of a guitar  10  produced according to the present invention is epoxied directly to the neck block  30 , thereby forming a butt-type neck joint  38 . The foot  15  functions to support the neck  14  and secure the neck joint  38 . Epoxy is the preferred glue due to, its resistance to humidity, its inherent strength, and its durability. The joint  38  is further strengthened by several graphite rods  42  that extend from the neck  14  into the neck block  30  and finally abut a rectangular graphite plate  44 , which is epoxied to the soundboard  16 . The soundboard support ribs  26  also abut the graphite plate  44 .  
         [0038]    [0038]FIG. 5 illustrates a diagrammatic view, unrestricted by a soundboard  16  or a fingerboard  13 , of a guitar  10  constructed according to the present invention. Four graphite rods, two rods being short  42 , and two rods being long  40 , along with a traditional truss rod  46 , support the neck  14  and neck joint  38 . The two short rods  42  extend from the plate  44 , through the neck block  30 , and approximately six inches up into the neck  14 . The two long rods  40  extend from the plate  44  up to the headstock  24 . This arrangement of graphite ribs  26 , plate  44  and rods  42 ,  40  produces a guitar  10  that is stronger, lighter weight, and better sounding than conventional designs.  
         [0039]    It is to be understood that the present invention is not limited to the sole embodiment described above, but encompasses any and all embodiments within the scope of the following claims.