# Patent

## Title
Stringed musical instrument with rotating neck

## 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.

## Background
FIELD OF THE INVENTION
The invention relates to stringed musical instruments and, in particular, 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's intonation can be radically disturbed and, lastly, wood under tension settles—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’, i.e. operative, state.
FIG. 2 is a side view of the same embodiment of the instrument in the folded ‘in-transit’ state.
FIGS. 3a and 3b 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. 5a and 5b are side and top views of one embodiment of the invention in the unfolded ‘playing’ state.
FIGS. 6a and 6b are side and top views of the neck roller assembly.
FIGS. 7a and 7b are side and top views of the bridge roller assembly.
FIG. 8 is a top view of one embodiment of the invention.



DETAILED DESCRIPTION OF THE INVENTION
The present invention is manufactured with all 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 1. 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 2. In other words, string tension is maintained by coupling neck roller assembly 1 to bridge roller assembly 2 via coupling system 3. 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'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 (1⁄8′′) braided steel cable. The cable is wrapped from anchor point 203a to anchor point 203b via the following path: under bridge cable roller 204a, down rigid structure 8, over neck cable roller 104a, through neck cable channel 105, over neck cable roller 104b, back down rigid structure 8, and under bridge cable roller 204b. 
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 104a and 104b. Similarly, as bridge roller assembly 2 un-wraps the reservoir of string from itself, the cable ‘wraps’ around cable rollers 204a and 204b. 
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, 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. 6a and 6b, in one embodiment of the neck roller assembly 1, assembly 1 includes, in part, nested cable rollers 104a and 104b, axle 101, rods 106a and 106b, and neck conduit 105. Nested cable rollers 104a and 104b, which may be made from a hard wood (such as maple) or aluminum, may have diameters of approximately two and one quarter inches (21⁄4′′) and approximately one inch (1′′), respectively. In turn, axle 101, which transverses the opening in the center of nested cable roller 104b, may be made from stainless steel or aluminum, and may have a diameter of approximately three eighths of an inch (3⁄8′′). Neck conduit 105, located above nested cable roller 104a in this embodiment, may have a diameter of approximately one eighth inches (1⁄8′′) in this embodiment.
Nested cable roller 104a, nested cable roller 104b, axle 101 and/or neck conduit 105 may have the same length or, as shown in FIG. 6b, may have varying lengths. For example, axle 101 may have a greater length than nested cable rollers 104a and 104b, and nested cable roller 104b may have a greater length than nested cable roller 104a. Typically, neck conduit 105 has a length approximately equal to the width between approximately parallel rods 106a and 106b. 
Further, as shown in FIG. 6b, axle 101 (along with nested cable rollers 104a and 104b and neck conduit 105) is mounted on approximately parallel rods 106a and 106b. In this embodiment, rods 106a and 106b are approximately square steel rods with approximately one quarter inch (1⁄4′′) sides. Rods 106a and 106b 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, rods 106a and 106b 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 FIGS. 7a and 7b, in one embodiment of the bridge roller assembly 2, assembly 2 includes, in part, nested cable rollers 204a and 204b, axle 201, and bridge roller string mounts 202a and 202b. Nested cable rollers 204a and 204b, which may be made from a hard wood (such as maple) or aluminum, may have diameters of approximately two and one quarter inches (21⁄4′′) and approximately one inch (1′′), respectively. In turn, axle 201, which transverses the opening in the center of nested cable roller 204b, may be made from stainless steel or aluminum, and may have a diameter of approximately three eighths inches (3⁄8′′). Bridge roller string mount 202a may be tangential to nested cable roller 204a, and bridge roller string mount 202b may be tangential to nested cable roller 204. Further, in this embodiment, bridge roller string mounts 202a and 202b may have diameters of one eighth inches (1⁄8′′) and three thirty second inches ( 3/32′′), respectively.
Nested cable roller 204a and nested cable roller 204b may have the same lengths or, as shown in FIG. 7b, may have varying lengths. In turn, in this embodiment, axle 201 may have a greater length than nested cable rollers 204a and 204b. Further, as shown in FIG. 7b, axle 201 (along with nested cable rollers 204a and 204b and bridge roller string mounts 202a and 202b) 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 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 (1⁄4′′) 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.

## Claims

1. A stringed instrument, such as a guitar, comprising:
an instrument body having a front face and a rear face;
a neck roller assembly, pivotably coupled to the instrument body by means of a neck roller joint axle mounted therein, for pivotal movement of the neck roller assembly between operative and folded positions;
an instrument neck secured at one of its ends to the neck roller assembly and having string receiving means at its other end providing a string tension anchor point on the instrument neck, wherein the instrument neck in its folded position lies opposite to the rear face of instrument body and in its operative position lies at an adjustable angle in the same plane as the front face of the instrument body;
a bridge element mounted on the instrument body and providing a string tension anchor point on the instrument body;
a bridge roller assembly, pivotably coupled to the instrument body by means of a bridge roller joint axle, to permit pivotal movement of the bridge roller assembly;
at least one string secured to the bridge roller assembly at one end thereof and extending over the bridge element and secured to the string receiving means of the neck at its other end thereof;
a cable assembly for flexible coupling between the neck roller assembly and the bridge roller assembly, the cable assembly providing proportional coupling of pivotal movement of the neck roller assembly to pivotal movement of the bridge roller assembly such that the length and tension of the at least one string is reduced when the neck roller assembly is moved between its operative position and its folded position.

2. The stringed instrument according to claim 1 wherein the rear face of the instrument body is formed with an integral neck body channel and wherein the instrument neck in its folded position lies within the integral neck body channel.

3. The stringed instrument according to claim 1 wherein the neck roller assembly comprises a neck string roller mounted radially around the neck roller joint axle, a neck cable roller mounted radially around the neck roller joint axle and having a conduit receiving the neck roller joint axle, the neck cable roller being attached to the neck string roller such that the two move together radially about the neck roller joint axel, a neck mount attached to the instrument neck and the rear facing side of the neck string roller to connect the neck roller assembly to the instrument neck, a neck cable mount positioned within the neck string roller anchoring the cable roller and rotatable with it.

4. The stringed instrument according to claim 1 wherein the bridge roller assembly comprises a bridge string roller mounted radially around the bridge roller joint axle, a bridge cable roller mounted radially around the bridge roller joint axle and having a conduit receiving the bridge roller joint axle, the bridge cable roller being attached to the bridge string roller such that the two move together radially about the bridge roller joint axle, a string mount mounted circumferentially on the bridge string roller to anchor the at least one string and a bridge cable mount mounted circumferentially on the bridge cable roller to anchor the cable assembly to bridge roller assembly.

5. The stringed instrument according to claim 4 wherein the bridge string roller is of such a size that it does not rotate more than 300 degrees in response to said pivotal movement of said neck roller assembly.

6. The stringed instrument according to claim 1 wherein the cable assembly comprises a steel stranded cable and two termination ends, one end attached to a bridge cable mount, the other end attached to a neck cable mount.

7. The stringed instrument according to claim 1 wherein the cable assembly comprises a steel stranded cable having two ends, one end attached to a bridge cable mount, the other end attached to a neck cable mount and wherein a third point on the cable is non-permanently attached to the instrument body.

8. The stringed instrument according to claim 7 wherein the cable assembly tension is adjusted with one or more cable tensioner rollers.

9. The stringed instrument according to claim 1 wherein the cable assembly according to claim 8 is not permanently affixed to either the neck cable mount or the bridge cable mount.

10. The stringed instrument according to claim 1 wherein the adjustable angle in the operative position is locked into position, arresting the pivotal movement of said neck roller assembly.

11. The stringed instrument according to claim 1, additionally comprising means for adjusting the string tension between the bridge roller assembly and the bridge.

12. The stringed instrument according to claim 11 wherein the string tension adjustment means includes one or more springs, a spring mount, and tension bar mounted to the springs and in tensile contact with the strings between the bridge roller assembly and the bridge.

13. The stringed instrument according to claim 12, additionally comprising a means for changing the position of the tension bar perpendicular to the face of the instrument body.

14. The stringed instrument according to claim 13 wherein the tension bar is free to move as the neck and the neck roller assembly are moved between their operative and folded positions.