Abstract:
An electric guitar has a body, a neck projecting from the body, strings stretched over the body and the neck and a pick-up attached to the body under the strings for producing an electric signal representative of vibrations of the strings, wherein the body has a body frame of metal/alloy or synthetic resin, a center block formed of metal/alloy/synthetic resin or wood and fixedly accommodated in the inner space of the body frame and deck plates adhered to both surfaces of the body frame so that a manufacturer produces the body through a simple process.

Description:
FIELD OF THE INVENTION 
     This invention relates to a stringed musical instrument and, more particularly, to a body structure of a stringed musical instrument such as, for example, an electric guitar. 
     DESCRIPTION OF THE RELATED ART 
     The electric guitar comprises a body, a neck projecting from the body and strings stretched over the body and the neck. The body is broken down into a solid structure and a semi-acoustic structure. A typical example of the solidtype body is disclosed in Japanese Utility Model Publication of Examined Application No. 55-36872. The solid-type body disclosed therein is formed of wood, and a wooden block is shaped into the complicated configuration. The body is perfectly solid, or a hollow space is formed in the body. 
     On the other hand, a typical example of the semi-acoustic type body is disclosed in Japanese Utility Model Publication of Examined Application No. 55-2460. Several wooden deck plates and panels are assembled into the semi-acoustic type body. The wooded deck plates/ panels are a front deck plate, a back deck plate, side plates and a center block, and defines a resonator inside of the body. The front deck plate, the back deck plate and the side plates are, by way of example, formed of silver fir or spruce. On the other hand, the center block is usually formed of maple. 
     FIG. 1 illustrates a typical example of the electric guitar. The prior art electric guitar has a solid body  1 , a neck  2 , strings  3 , a bridge  4 , pick-ups  5 , a tail piece  6 , dials  7  and a power switch  8 . The solid body  1  is formed of wood, and has a unique configuration. The solid body  1  has a front surface, a back surface and a side surface. Although the neck  2  is separated from the solid body  1  in FIG. 1, the neck  2  is fixed to the solid body  1 , and projects from the side surface of the solid body  1 . The tail piece  6  is attached to the front surface, and is located on the opposite side to the neck  2 . The bridge  4  and the pick-ups  5  are also attached to the front surface, and are positioned between the neck  2  and the tail piece  6 . The strings  3  are stretched between pegs at the leading end of the neck  2  and the tail piece  6 , and the bridge  4  and the pick-ups  5  are under the strings  3 . The bridge  4  gives appropriate tension to the strings  3 . The pick-ups  5  detect vibrations of the strings  3 , and convert the vibrations to electric signals. Though not shown in FIG. 1, the pick-ups  5  are connected to a suitable amplifier, which makes a speaker system generate electric sounds. When the power switch  8  turns on, the dials  7  and the pick-ups  5  are energized. A player manipulates the dials  7  in order to regulate the volume, the tone color etc. 
     The solid body  1  is formed as follows. Prior to a machining, an aging is required for a wooden block to be machined. The wooden block is 40 to 50 millimeters thick. The wooden block is shaped into the unique configuration by using wood working machines. The wood work is polished, and, thereafter, is painted. A rough coating is carried out for the wood work, and a primer coating, a polishing, an intermediate coating, a polishing, a finish coating and a polishing follows. Thus, the polishing and the coating are repeated, and the prior art solid body  1  is obtained. 
     After completion of the solid body  1 , the bridge  4 , pick-ups  5 , the tail piece  6 , the dials  7  and the power switch  8  are attached to the solid body  1 , and the neck  2  is connected to the solid body  1 . Finally, the strings  3  are stretched between the pegs and the tail piece  6 . 
     FIG. 2 shows a semi-acoustic body of another prior art electric guitar. The semi-acoustic body has a built-up structure. A front deck plate  11 , a back deck plate  12  and a side plate  13  form a hollow space  14 , and a center block  15  is provided between the front deck plate  11  and the back deck plate  12 . Strings  16  are stretched over the front deck plate  11 . 
     The prior art semi-acoustic body is manufactured through a process similar to that of the prior art solid body. The aging step, machining steps, an assembling step, the painting steps and the polishing steps are incorporated in the process for fabricating the semi-acoustic body. 
     As described hereinbefore, the prior art bodies, i.e., both solid and semi-acoustic bodies are formed of wood. However, the manufacturer suffers from high production cost of the wooden body. This is because of the fact that the wood work passes the various steps during the manufacturing. The aging step, the machining steps, the polishing steps and the coating steps form the manufacturing process, and the manufacturer consumes a large amount of time and labor for the prior art body. Especially, the coating steps and the polishing steps are indispensable to the wood work, and are time-consuming. In fact, the manufacturer consumes fifty percent of the time required for the manufacturing. Thus, the prior art wooden bodies are low in productivity, and the manufacturer suffers from the high production cost. This is the first problem inherent in the prior art bodies. 
     The second problem is the exhaust of the forest resources due to the deforestation. It is getting more difficult to obtain the wood. 
     The third problem is the machinability of the wood. The wood is brittle, and the brittleness set a limit on the configuration of the wooden body. 
     SUMMARY OF THE INVENTION 
     It is therefore an important object of the present invention to provide a stringed musical instrument, a body of which is low in production cost, easy to obtain materials and high in machinability. 
     To accomplish the object, the present invention proposes to use a body frame formed of metal, alloy or synthetic resin. 
     In accordance with one aspect of the present invention, there is provided a stringed musical instrument comprising a body including a body frame formed of a first material selected from the group consisting of metal, alloy and synthetic resin and having an inner space open to a front surface and a back surface thereof, a center block formed of a second material and accommodated in the inner space and deck plates formed of a third material and fixed to the front surface and the back surface so as to confine the center block in the inner space, and at least one string stretched over the front deck plate. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The features and advantages of the stringed musical instrument will be more clearly understood from the following description taken in conjunction with the accompanying drawings in which: 
     FIG. 1 is a perspective view showing the prior art electric guitar, the solid body of which is separated from the neck; 
     FIG. 2 is a cross sectional view showing the structure of the semi-acoustic body forming the part of the prior art electric guitar; 
     FIG. 3 is an exploded perspective view showing a body of an electric guitar according to the present invention; 
     FIG. 4 is a perspective view showing the body after the assemblage; 
     FIG. 5 is a cross sectional view taken along line A—A of FIG.  4  and showing the structure of the body; and 
     FIG. 6 is a perspective view showing a wood work to be polished by a polishing machine. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings, and in particular to FIGS. 3,  4  and  5 , a body forming a part of an electric guitar embodying the present invention is shown and generally indicated at  20 . The body  20  comprises a body frame  21 , a front deck plate  22 , a back deck plate  23  and a center block  24 . The body frame  21  has a contour identical with those of the front/back deck plates  22 / 23 . The center block  24  is accommodated inside the body frame  21 , and the center block  24  and the body frame  21  are sandwiched between the front deck plate  22  and the back deck plate  23 . 
     The body frame  21  is formed of metal, alloy such as, for example, aluminum alloy or magnesium alloy or synthetic resin, and has two partition walls  21   a / 21   b . Conductive synthetic resin may be used for the body frame  21 . The conductive synthetic resin is effective against noise. The two partition walls  21   a / 21   b  divides the inner space into three sections  21   c / 21   d . The section  21   c  is assigned to the center block  24 , and has a contour corresponding to that of the center block  24 . For this reason, the center block  24  is snugly received in the section  21   c , and is fixed between the front deck plate  22  and the back deck plate  23 . The other sections  21   d  are empty, and make the body frame  21  light. Electric components such as a power switch and dials are attached to the front deck plate  22 , and partially project into the sections  21   d . The power switch and the dials are similar to the power switch  8  and the dials  7 , and are not shown in the figures. The electric components are connected through a cable (not shown) to a socket (not shown), and the socket is open to a hole  21   j  formed in the rear portion of the body frame  21 . A plug is insertable through the hole  21   j  to the socket, and the electric components are connected through the plug-and-socket connector and a cable to an amplifier (not shown). 
     The rear portion of the body frame  21  is rounded, and horn-like projections  21   e / 21   f  are formed on the opposite side. The horn-like projection  2   e  is longer than the other horn-like projection  21   f , and the horn-like projections  21   e / 21   f  are connected to each other so as to form a gently curved surface  21   h . The body frame  21  is constricted between the rear end portion and the horn-like projections  21   e / 21   f , and the constricted portion  21   g  is gently curved. 
     The center block  24  is formed of synthetic resin or wood. If the metal/alloy and/or the synthetic resin is used for the body frame  21  and the center block  24 , the manufacturer reduces the amount of wood to be required, and a fabrication process is made simple, because neither coating nor polishing step is incorporated in a fabrication process. 
     The center block  24  has a depression  24   a  and recesses  24   b / 24   c / 24   d / 24   e . The boss portion of a neck  25  is snugly received in the depression  24   a , and is fixed to the center block  24  by means of bolts. Strings  26  are stretched over the neck  25  and the body  20 , and are anchored at pegs and a tail piece as similar to the prior art electric guitar. The recesses  24   b / 24   c / 24   d  are assigned to pick-ups corresponding to the pick-ups  5  (see FIG.  1 ), and the recess  24   e  is assigned to a bridge corresponding to the bridge  4 . The pick-ups and the bridge are respectively accommodated in the recesses  24   b / 24   c / 24   d  and the recess  24   e , and project over the front deck plate  22 . The center block  24  is gradually decreased in thickness from the center portion toward the side portions (see FIG.  5 ). 
     If the manufacturer selects alloy such as the aluminum alloy or the magnesium alloy for the body frame  21  and the center block  24 , the body frame  21  and the center block  24  may be shaped into the configurations by using a die-casting technique. On the other hand, if the synthetic resin is selected, the body frame  21  and/or the center block  24  may be formed through an injection molding. Thermoplastic resin and thermosetting resin are available for the body frame  21  and/or the center block  24 . It is desirable to use a conductive synthetic resin such as, for example, carbon- containing synthetic resin or copper- containing synthetic resin enhances anti-noise property of the body  20 . The carbon particles or the copper particles may be dispersed in polyurethane or polyester. The synthetic resin is easily colored, and any painting step is required. Thus, the usage of synthetic resin makes the fabrication process simple. 
     The front deck plate  22  and the back deck plate  23  have the contour identical with that of the body frame  21  as described hereinbefore. Although any hole is not formed in the back deck plate  23 , the front deck plate  22  is partially cut away so as to form a cut-away  22   a , and through-holes  22   b / 22   c / 22   d / 22   e  are formed in the front deck plate  22 . An inner periphery defining the cut-away  22   a  is identical with the inner periphery of the center block  24  defining the depression  24   a , and, for this reason, the depression  24   a  is over-lapped with the cut-away  22   a . The inner peripheries of the front deck plate  22  defining the through-holes  22   b / 22   c / 22   d / 22   e  are also identical with the inner peripheries of the center block  24  defining the recesses  24   b / 24   c / 24   d / 24   e , respectively, and the recesses  24   b / 24   c / 24   d / 24   e  are respectively over-lapped with the through-holes  22   b / 22   c / 22   d / 22   e . Small circular holes  22   f  are further formed in the front deck plate  22 . Manipulating levers pass through the small circular holes  22   f , and knobs are respectively attached to the leading ends of the manipulating levers. 
     The front deck plate  22  and the back deck plate  23  are formed of wood, metal, alloy, synthetic resin or composite material such as, for example, carbon-graphite. If the manufacturer selects the wood, several kinds of veneer board are available for the front deck plate  22  and the back deck plate  23 . The veneer board may be formed from pieces of horse chestnut or pieces of sycamore. Aluminum alloy is an example of the alloy. 
     If the manufacturer selects the metal, the alloy or the synthetic resin, metal/alloy/synthetic resin plates are shaped into the front deck plate  22  and the back deck plate  23  by using a punching machine, and any painting step is not required. As a result, the fabrication process is made simple. 
     If the manufacturer selects a veneer board, veneer boards are shaped into the front deck plate  22  and the back deck plate  23  by using a CNC (Computer Numerical Control) router machine or a template, and the wood works are painted and polished. FIG. 6 illustrates the wood work  22  to be polished by a polishing machine  28 . The wood works may be painted by using a roll coater (not shown), and the polishing machine may be an automatic polisher or a buff machine. Even if the front deck plate  22  and the back deck plate  23  are formed of wood, the wood works are flat, and are simpler than the solid wooden body. For this reason, the painting steps are easier than those for the solid wooden body are, and the manufacturer enhances the productivity of the body  20 . 
     Upon completion of the painting/polishing steps, the painted wood works are deformed, and are shaped into the front deck plate  22  and the back deck plate  23 . The front deck plate  22  and the back deck plate  23  are adhered to the body frame  21  and the center block  24 . 
     As will be appreciated from the foregoing description, the body frame  22  is formed of metal/alloy or synthetic resin, and the metal/alloy and the synthetic resin are available for other parts, i.e., the center block  24 , the front deck plate  22  and the back deck plate  23 . The metal, the alloy and the synthetic resin are abundant, and are not costly. Neither painting step nor polishing step is required for the body frame  22 , and the fabrication process is simple. The body frame  22  serves as a side panel, and allows the manufacturer to delete the side panel from the structure. Thus, the body  20  makes the manufacturer reduce the production cost of the stringed musical instrument. 
     Metal or alloy is shaped into the body frame  22  through a casting, and synthetic resin is shaped into the body frame  22  through a molding. Using the casting/molding, the manufacturer can freely give a novel design to the body  20 , and makes the stringed musical instrument attractive to users. 
     The body frame  22  imparts a unique tone color to the electric sounds. The metal and the alloy are recycled, and are desirable from the viewpoint of the conservation of resources. 
     When the body frame  22  is formed of aluminum alloy or magnesium alloy, the electric guitar is light, and the body  20  formed of the conductive material is enhanced in anti-noise property. On the other hand, if the synthetic resin is used, the manufacturer arbitrarily colors the body  20 . The front deck plate  22  and the back deck plate  23  both formed from the veneer boards make the stringed musical instrument a higher grade. 
     Although the particular embodiment of the present invention has been shown and described, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the present invention. 
     Various contours may be given to the body frame  21  and, accordingly, the front/back deck plates  22 / 23 . 
     The body frame  21  may be integral with the center block  24 . If so, both of the body frame  21  is identical in material with the center block  24 , and the fabrication process is further simplified. 
     The present invention is applicable to any kind of stringed musical instrument such as, for example, an acoustic stringed musical instrument and another kind of electric stringed musical instrument.