Abstract:
Provided is a foldable stringed having a rotating neck in which the fret board in the folded position is opposite the rear face and the mechanism employs a flexible cable system under variable tension.

Description:
REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. Ser. No. 14/551,124 filed Nov. 24, 2014 (now U.S. Pat. No. 9,224,370) and claims priority thereto. The disclosure of U.S. Pat. No. 9,224,370 is herein incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to stringed musical instruments. In particular, the invention relates to stringed musical instruments that are more manageable for traveling. 
     BACKGROUND OF THE INVENTION 
     The construction of stringed musical instruments has been around for a long, long time, and they have evolved to the point where we take for granted a standard arrangement of common elements. For example, most non-electric stringed musical instruments have a headstock, tuners (geared assemblies for applying tension to strings), a neck, strings, and a body. For electric stringed musical instruments, pickups with associated electronics and, perhaps, a vibrato bar are common additional elements. Further, guitar players like fairly standard dimensions from the nut (the string vibration terminus at the neck) to the bridge (the string vibration terminus at the body) of between 24.75 and 25.5 inches. In short, musicians do not want instruments that have odd arrangements of elements and most certainly do not want those elements dismantled. They like what they are used to, with modest differences in preference to style and performance. 
     Today, guitars and basses are approximately 36 inches to 48 inches long from the top of the headstock to the end of the body. This length creates difficulties for transport, and with the delicate neck consuming about three-quarters of this length, many solutions involve detaching the neck or “hinging” the neck. For example, U.S. Pat. Nos. 4,191,085, 5,353,672, and 6,956,157 describe clips and clamps and other machinations for removing the neck from the body of the guitar for ease of transport. Unfortunately, once the neck is removed, the strings flop, bend, and kink. The instrument&#39;s intonation can be radically disturbed and, lastly, wood under tension settle—much like a house settles. In a worst case scenario, the neck can warp. U.S. Pat. No. 8,203,058 describes hinging the neck onto the body and dropping the fret board onto the face of the guitar during travel. Here, the top of the guitar can be marred by the neck flopping on top of it, and the fret board can be marred by an errant string peg or sharp bridge assembly. Further, as noted above, with the neck released from tension, the strings flop, bend, and kink. U.S. Pat. No. 7,365,254 also describes hinging the neck, but when the fret board is dropped onto the face of the guitar a spring-loaded roller takes up the slack of the strings. Once again, the top of the guitar and the fret board can be marred. Further, in the process of rolling up the strings, the strings can crisscross and kink, and the tension of the strings on the roller during transit is not controlled relative to the tension of the strings while playing. 
     U.S. Pat. No. 4,111,093 describes an instrument with a rotating neck wherein the fret board in the folded position is opposite the rear face and the mechanism employs a rack and pinion roller coupling system, resulting in rigid rotational having a fixed tension. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of one embodiment of the invention in the unfolded ‘playing’ state. 
         FIG. 2  is a side view of the same embodiment of the instrument in the folded ‘in-transit’ state. 
         FIGS. 3 a  and 3 b    are side and top views of another embodiment of the invention in the unfolded ‘playing’ state. 
         FIG. 4  is a side view of still another embodiment of the invention in the unfolded ‘playing’ state. 
         FIGS. 5 a  and 5 b    are side and top views of one embodiment of the invention in the unfolded ‘playing’ state. 
         FIGS. 6 a  and 6 b    are side and top views of another embodiment of the invention in the unfolded ‘playing’ state. 
         FIGS. 7 a  and 7 b    are side and top views of a further embodiment of the invention in the unfolded ‘playing’ state. 
         FIG. 8  is a top view of one embodiment of the invention. 
         FIG. 9  is a perspective view of a different embodiment of the neck roller assembly shown in  FIG. 6 . 
         FIG. 10  is a perspective view of a different embodiment of the bridge roller assembly shown in  FIG. 7 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention is manufactured with al  11  the standard processes available for stringed musical instruments. For example, as shown in  FIG. 1 , neck and fret board assembly  7  are mounted to neck roller assembly  1  using neck mount  4 . Neck mount  4  is substantially the same as, if not exactly the same as, any four-screw, bolt-on-neck arrangement. In contrast, bridge roller assembly  2  replaces the standard stud mount, trapeze or vibrato tailpiece. 
     In  FIGS. 1 and 2 , one embodiment of the invention is shown in both its unfolded ‘playing’ state and its folded ‘in-transit’ state, respectively. In particular, when the neck moves from an unfolded, operative, position to a folded position, strings  9  remain under tension by the anchoring between anchor points  202  and  701  over bridge element  5 , and the strings will, in turn, wrap around the neck roller assembly. 
     Strings  9  remain under tension because the length of string required to wrap around neck roller assembly  1  comes from a reservoir of string controlled in bridge roller assembly. In other words, string tension is maintained by coupling neck roller assembly  1  to bridge roller assembly  2  via the coupling system. Thus, the string tension in the folded position may be the same as, or different from, the string tension in the unfolded position. 
     When in a folded position, and as shown in  FIG. 2 , the neck is resting against the back of the stringed musical instrument. In an alternative embodiment, the neck sits within a cavity in the back of the instrument. In this embodiment, the neck may sit partially within the opening (that is, not flush with the back of the guitar), or fully within the opening (that is, flush with the back of the guitar). 
     Coupling system  3  may comprise gears, motors, or other mechanisms known to a person of ordinary skill in the art. Further, it cannot interfere with the instrument&#39;s wood, sound quality, structure, performance, electronics, or playing area. As shown in  FIG. 3 , one embodiment for coupling system  3  includes a high strength, low stretch cable, such as one-eighth inch (⅛″) braided steel cable. The cable is wrapped from anchor point  203   a  to anchor point  203   b  via the following path: under bridge cable roller  204   a , down rigid structure  8 , over neck cable roller  104   a , through neck cable channel  105 , over neck cable roller  104   b , back down rigid structure  8 , and under bridge cable roller  204   b.    
     With this arrangement, the new anchor point for tension is now ‘floating’ on neck roller assembly  1 . Thus, as the strings wrap around neck roller assembly  1 , that is, as the neck moves from its unfolded position to its folded position, the tension remains constant as the cable ‘un- wraps’ around cable rollers  104   a  and  104   b . Similarly, as bridge roller assembly  2  un-wraps the reservoir of string from itself, the cable ‘wraps’ around cable rollers  204   a  and  204   b.    
     To maintain control of the relationship between neck roller assembly  1  and bridge roller assembly  2 , the linear dimension of the strings must be controlled. For example, as shown and described in  FIG. 9 , for a high ‘E’ string (329.63 Hz), a 12:1 tuner requires nearly a complete turn to change the note by half a step. A half step translates to about three sixty fourths inch ( 3/64″) of linear string length. Thus, the linear dimension of the strings must be controlled to within about one sixty fourth ( 1/64) of an inch. In other words, the tension of the strings in an un-folded position and the tension of the strings in a folded position may be controlled with: (1) differences in the diameters of the rollers in neck roller assembly  1  and bridge roller assembly  2 ; (2) differences between the ratios of the cable rollers in neck roller assembly  1  and their respective cable rollers in bridge roller assembly  2 ; and (3) changes to the shape of the cable rollers in either or both neck roller assembly  1  and bridge roller assembly  2  (for example, from circular to elliptical) using intermediate states of tension as the neck moves from an unfolded position to a folded position. 
     To achieve control better than (or alternative to) one sixty fourth ( 1/64) of an inch, intermediate coupling may be used. For example, as shown in  FIG. 4 , coupling system  3  may be composed of springs  304  and  305 , lever  303 , and rollers  302  and  312 . In an alternate embodiment, the instrument may include vibrato arm assembly  350 . 
     In  FIGS. 6 a  and 6 b   , in one embodiment of the neck roller assembly  1 , assembly  1  includes, in part, nested cable rollers  104   a  and  104   b , axle  101 , rods  106   a  and  106   b , and neck conduit  105 . Nested cable rollers  104   a  and  104   b , which may be made from a hard wood (such as maple) or aluminum, may have diameters of approximately two and one quarter inches (2¼″) and approximately one inch (1″), respectively. In turn, axle  101 , which transverses the opening in the center of nested cable roller  104   b , may be made from stainless steel or aluminum, and may have a diameter of approximately three eighths of an inch (⅜″). Neck conduit  105 , located above nested cable roller  104   a  in this embodiment, may have a diameter of approximately one eighth inches (⅛″) in this embodiment. 
     Nested cable roller  104   a , nested cable roller  104   b , axle  101  and/or neck conduit  105  may have the same length or, as shown in  FIG. 6 b   , may have varying lengths. For example, axle  101  may have a greater length than nested cable rollers  104   a  and  104   b , and nested cable roller  104   b  may have a greater length than nested cable roller  104   a . Typically, neck conduit  105  has a length approximately equal to the width between approximately parallel rods  106   a  and  106   b.    
     Further, as shown in  FIG. 6 b   , axle  101  (along with nested cable rollers  104   a  and  104   b  and neck conduit  105 ) is mounted on approximately parallel rod  106 . In this embodiment, rod  106  is a square steel rod with approximately one quarter inch (¼″) sides. Rod  106  may be mounted to the body of the guitar with glue, screws, or a weld. As shown in  FIG. 8 , in one particular embodiment of the invention, the rod may be mounted to the body of the guitar such that axle  101  is mounted exactly in the middle of the thickness of the body. 
     In a second embodiment as shown in  FIG. 9 , the individual parts of the neck roller assembly  1  can be integrated into one or more structures to form a unitary architecture or configuration. By unitary, we mean any combination of at least two of the structures included in the neck roller assembly or the bridge roller assembly of the embodiments shown in  FIGS. 1-8 , particularly in  FIGS. 6-8 , in an integrated manner to form a single structure. For example, the neck mount  4  and the front string roller  104  that covers one of the nested cable rollers  104   b  (as shown in  FIG. 6A ) can be combined into a single structure. Further, the neck mount  4  and neck  7  can be formed of a single piece of wood (making the neck part of the neck roller assembly). Also, the neck mount, the front string roller and the neck can be integrated into a single, unitary structure. Further, referring now to  FIG. 3A  and  FIGS. 6A and 6B  the neck angle leveler  801  and the neck roller stop  106  can be combined into a unitary neck rotation stop,  901 , as shown in  FIG. 9 . Additionally, the cable  903  that comprises coupling system  3  and runs from bridge cable roller  204   b  to neck cable roller  104   b  through neck conduit  105  and then back to bridge cable roller  204   a  via neck cable roller  104   a  can be modified. In this modified embodiment the cable terminates at neck cable roller  104   b  and is attached thereto, eliminating the need for neck cable conduit  105  and the return of the cable to the other side of the bridge cable roller  204   a  and thereby also eliminating the need for bridge cable roller  204   a . Cable  903  is held in position on neck cable roller  104   b  by cable anchor  902 . The cable terminates at each end into cable balls  909 , along with cable anchor  902  prevent the cable from moving once anchor  902  is tightened. See  FIG. 9 . 
     In  FIGS. 7 a  and 7 b   , in one embodiment of the bridge roller assembly  2 , assembly  2  includes, in part, nested cable rollers  204   a  and  204   b , axle  201 , the bridge string roller and bridge roller string mount  202 . Nested cable rollers  204   a  and  204   b , which may be made from a hard wood (such as maple) or aluminum, may have diameters from two and one quarter inches (2¼″) to approximately one inch (1″). In turn, axle  201 , which transverses the opening in the center of nested cable rollers  204   a  and  204   b , may be made from stainless steel or aluminum, and may have a diameter of approximately three eighths inches (⅜″). Bridge roller string mount  202  may be tangential to nested cable roller  204   a.    
     Nested cable roller  204   a  and nested cable roller  204   b  may have the same lengths or may have varying lengths. In turn, in this embodiment, axle  201  may have a greater length than nested cable rollers  204   a  and  204   b . Further, as shown in  FIG. 7 b   , axle  201  (along with nested cable rollers  204   a  and  204   b  and bridge roller string mount  202  is mounted as a replacement for a standard stud mount, trapeze or vibrato tailpiece within opposing bore holes in the body of the guitar. 
     In a second embodiment of the bridge roller assembly shown in  FIG. 10 , the individual parts of the assembly can be integrated into a unitary structure as was described for the neck roller assembly. For instance, bridge roller string mount  202  and the string roller  906  that forms part of the bridge roller assembly  2  can be formed as a unitary mechanism. Also, because of the elimination of the neck conduit  105  and the positioning of the cable on only one side of the neck and bridge roller assemblies, the mechanisms on the opposite side of these assemblies will become superfluous and can be eliminated. 
     In other embodiments of the invention, neck roller assembly  1  may be mounted in the same plane as bridge roller assembly  2 , in a higher plane than bridge roller assembly  2 , or in a lower plane than bridge roller assembly  2 . In  FIG. 8 , for example, bridge roller assembly  2  is mounted one quarter inches (¼″) lower than neck roller assembly  1 . With such a configuration, the strings from 5 to 2 may have an approximately 10° angle. 
     To prevent the neck from rotating into a folded position during a performance, and as understood by a person of ordinary skill in the art, various mechanisms may be used. For example, and as shown in  FIG. 4 , neck roller stop  106  (a pin mechanism) prevents neck movement. Similarly, to prevent the neck from flopping onto the face of the instrument, and as understood by a person of ordinary skill in the art, various mechanisms may be used. For example, and as shown in  FIG. 3 , neck angle leveler  801  keeps the neck from flopping. It also allows for proper neck angle and action adjustment in the unfolded position. In the embodiment shown in  FIGS. 9 and 10 , the neck angle leveler  801  and the neck roller stop  106  can be combined into a unitary neck rotation stop,  901 .