Patent Publication Number: US-11663996-B1

Title: Foldable stringed instrument and related methods

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     The present application is a non-provisional patent application claiming benefit under 35 U.S.C. § 119(e) from U.S. patent application Ser. No. 63/016,788 filed Apr. 30, 2020, the entire contents of which is hereby expressly incorporated by reference into this disclosure as if set forth fully herein. 
    
    
     BACKGROUND OF THE INVENTION 
     I. Field of the Invention 
     The present invention relates generally to musical instruments and, more particularly, to a foldable fretted stringed instrument (such as a guitar) including an actuator to facilitate string management and folding/unfolding. 
     II. Discussion of the Prior Art 
     Stringed instruments, such as guitars, have enjoyed among the highest popularity among musical instruments. Most stringed instruments have a solid neck rigidly coupled to either a hollow or solid body. This construction, while aiding in predictable tuning and quality of play, render many stringed instruments cumbersome for travel (e.g. air, train, auto, etc. . . . ), particularly given the additional bulk of the associated case (hard or soft). While various stringed instruments have been attempted to make it easier and/or more convenient to travel with or store these stringed instruments, most are simply smaller or scaled down versions of their traditional counterparts, which still present challenges for travel and/or predictable tuning and quality of play. The present invention is directed at improving upon the current options available for foldable stringed instruments. 
     SUMMARY OF THE INVENTION 
     The present invention accomplishes this goal by providing a foldable stringed instrument including an actuator system to facilitate string management and folding/unfolding. The foldable stringed instrument folds mid-neck to assume a reduced profile. While referred to hereinafter within the context of an electric travel guitar, it will be appreciated that the scope of the invention extends beyond guitars and may include, by way of example only, any of a variety of stringed instrument that would benefit from a reduced profile for ease of travel and/or storage (e.g. acoustic guitar, bass guitar, ukulele, etc. . . . ). 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many advantages of the present invention will be apparent to those skilled in the art with a reading of this specification in conjunction with the attached drawings, wherein like reference numerals are applied to like elements and wherein: 
         FIGS.  1 - 2    are perspective views (assembled and exploded) of an actuator assembly forming part of a folding mechanism for a foldable fretted instrument according to aspects of the present invention; 
         FIGS.  3 - 4    are perspective views (front and back) top and bottom views of the actuator assembly according to aspects of the present invention; 
         FIGS.  5 - 6    are end views (upper and lower) of the actuator assembly according to aspects of the present invention; 
         FIG.  7    is a side view of the actuator assembly according to aspects of the present invention; 
         FIGS.  8 - 10    are perspective views of the actuator assembly in use during the process of rotating a handle from a stored state to retract a ram rod and release a floating tail piece assembly, which is the first phase of using the actuator assembly to fold a fretted instrument according to aspects of the present invention; 
         FIGS.  11 - 12    are perspective views of the actuator assembly in use during the process of rotating the handle back to the stored state after disengaging with rotating handle guides, which is the second phase of using the actuator assembly to fold a fretted instrument according to aspects of the present invention; 
         FIGS.  13 - 14    are perspective views of the actuator assembly in use during the process of rotating the handle from the stored state to reengage with the rotating handle guides, which is the first phase of using the actuator assembly to unfold a fretted instrument according to aspects of the present invention; 
         FIGS.  15 - 16    are perspective views of the actuator assembly in use during the process of rotating the handle back to the stored state after reengaging with rotating handle guides to deploy the ram rod and secure the floating tail piece assembly, which is the second step of using the actuator assembly to unfold a fretted instrument according to aspects of the present invention; 
         FIGS.  17 - 19    are side views of the actuator assembly in use during the process of rotating the handle shown in  FIGS.  8 - 10   , which is the first phase of using the actuator assembly to fold a fretted instrument according to aspects of the present invention; 
         FIGS.  20 - 21    are side views of the actuator assembly in use during the process of rotating the handle shown in  FIGS.  11 - 12   , which is the second phase of using the actuator assembly to fold a fretted instrument according to aspects of the present invention; 
         FIGS.  22 - 23    are side views of the actuator assembly in use during the process of rotating the handle shown in  FIGS.  13 - 14   , which is the first phase of using the actuator assembly to unfold a fretted instrument according to aspects of the present invention; 
         FIGS.  24 - 25    are side views of the actuator assembly in use during the process of rotating the handle shown in  FIGS.  15 - 16   , which is the second step of using the actuator assembly to unfold a fretted instrument according to aspects of the present invention; 
         FIGS.  26 A- 26 E  are various views of an upper rail mounting plate forming part of the actuator assembly of  FIGS.  1 - 7    according to aspects of the present invention; 
         FIGS.  27 A- 27 D  are various views of a first lower rail mounting plate forming part of the actuator assembly of  FIGS.  1 - 7    according to aspects of the present invention; 
         FIGS.  28 A- 28 D  are various views of a second lower rail mounting plate forming part of the actuator assembly of  FIGS.  1 - 7    according to aspects of the present invention; 
         FIG.  29    is a perspective view of a floating tail piece assembly forming part of the actuator assembly of  FIGS.  1 - 7    according to aspects of the present invention; 
         FIGS.  30 A- 30 C  are various views of a plate forming part of the floating tail piece assembly of  FIG.  29    according to aspects of the present invention; 
         FIGS.  31 A- 31 D  are various views of a truss lock member forming part of the actuator assembly of  FIGS.  1 - 7    according to aspects of the present invention; 
         FIGS.  32 A- 32 D  are various views of a linkage member forming part of the actuator assembly of  FIGS.  1 - 7    according to aspects of the present invention; 
         FIGS.  33 A- 33 E  are various views of a first handle guide forming part of the actuator assembly of  FIGS.  1 - 7    according to aspects of the present invention; 
         FIGS.  34 A- 34 E  are various views of a second handle guide forming part of the actuator assembly of  FIGS.  1 - 7    according to aspects of the present invention; 
         FIGS.  35 A- 35 E  are various views of a first handle arm forming part of the actuator assembly of  FIGS.  1 - 7    according to aspects of the present invention; 
         FIGS.  36 A- 36 E  are various views of a second handle arm forming part of the actuator assembly of  FIGS.  1 - 7    according to aspects of the present invention; 
         FIGS.  37 A- 37 F  are various views of a handle grip forming part of the actuator assembly of  FIGS.  1 - 7    according to aspects of the present invention; 
         FIGS.  38 A- 38 F  are various views of a handle cap forming part of the actuator assembly of  FIGS.  1 - 7    according to aspects of the present invention; 
         FIGS.  39 A- 39 C  are various views of a locking spring clip forming part of the actuator assembly of  FIGS.  1 - 7    according to aspects of the present invention; 
         FIGS.  40 A- 40 D  are various views of a wedge member forming part of the actuator assembly of  FIGS.  1 - 7    according to aspects of the present invention; 
         FIGS.  41 A- 41 D  are various views of a handle release button forming part of the actuator assembly of  FIGS.  1 - 7    according to aspects of the present invention; 
         FIG.  42    is a perspective view of a cable assembly forming part of the actuator assembly of  FIGS.  1 - 7    according to aspects of the present invention; 
         FIGS.  43 A- 43 C  are various views of a shaft forming part of the actuator assembly of  FIGS.  1 - 7    according to aspects of the present invention; 
         FIGS.  44 A- 44 C  are various views of a shaft guide forming part of the actuator assembly of  FIGS.  1 - 7    according to aspects of the present invention; 
         FIGS.  45 - 46    are front and back views, respectively, of a foldable stringed instrument in the form of (by way of example only) an electric guitar with the actuator assembly of  FIGS.  1 - 7    mounted in a recess in the back of the guitar body according to aspects of the present invention; 
         FIG.  47    is an enlarged perspective view of the body of the foldable stringed instrument of  FIGS.  45 - 46    with the neck in the fully extended state and the actuator engaged as shown and described in  FIG.  17    according to aspects of the present invention; 
         FIG.  48    is an enlarged perspective view of the body of the foldable stringed instrument of  FIGS.  45 - 46    with the neck in the fully extended state and the actuator dis-engaged as shown and described in  FIG.  18    according to aspects of the preset invention; 
         FIG.  49    is an enlarged perspective view of the body of the foldable stringed instrument of  FIGS.  45 - 46    with the neck in the fully extended state and the actuator dis-engaged as shown and described in  FIG.  19    according to aspects of the preset invention; 
         FIG.  50    is an enlarged view of the body of the foldable stringed instrument of  FIGS.  45 - 46    with the neck in the fully extended state and the actuator dis-engaged as shown and described in  FIG.  21    according to aspects of the preset invention; 
         FIG.  51    is an enlarged view of the body of the foldable stringed instrument of  FIGS.  45 - 46    with the neck in the folded state and the actuator dis-engaged as shown and described in  FIG.  21    according to aspects of the preset invention; and 
         FIGS.  52 - 54    are enlarged views of the body of the foldable stringed instrument of  FIGS.  45 - 46    showing the neck in the folding process to return to the playing, fully extended state in  FIG.  49   . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Illustrative embodiments of the invention are described below. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developers&#39; specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure. The actuator system disclosed herein boasts a variety of inventive features and components that warrant patent protection, both individually and in combination. 
       FIGS.  1 - 7    illustrate various features and components of an actuator assembly  10  forming part of a folding mechanism for a foldable fretted instrument according to aspects of the present invention. The actuator assembly  10  includes a handle assembly  12  rotatably coupled to a pair of handle guides  14 ,  16 , which are in turn rotatably coupled to a pair of lower mounting plates  18 ,  20  attached to a base plate  22 . The actuator assembly  10  may be mounted in any number of foldable stringed instruments, including (by way of example only) an electric guitar  200  shown in  FIGS.  45 - 46   . The electric guitar  200  includes a neck  202  mounted to a body  204 . The body  204  includes a back recess  206 . The base plate  22  is disposed within the recess  206  of body  204 . Under the direction of the handle assembly  12 , the actuator assembly  10  serves two primary functions to fold and unfold the stringed instrument: 1) it loosens and tightens the strings of the stringed instrument to enable folding and playing, respectively; and 2) it unlocks and locks a hinge forming part of the neck of the stringed instrument to enable folding and playing, respectively. 
     The handle assembly  12  includes a rounded grip  24 , a pair of arm members  26 ,  28  rotatably coupled to the handle guides  14 ,  16 , and a button  30  extending from the grip  24 . As best viewed in  FIG.  2   , binding posts  15  are used to rotatably couple the arm members  26 ,  28  within the handle guides  14 ,  16  and also rotatably couple the handle guides  14 ,  16  to the lower mounting plates  18 ,  20 . The button  30  is spring biased to extend through an aperture in the grip  24  of the handle assembly  12 . The button  30  cooperates with a locking mechanism disposed within the handle assembly  12  for the purpose of selectively locking and unlocking the arm members  26 ,  28  to and from the handle guides  14 ,  16 . The locking mechanism includes a cable assembly  32 , a pair of wedges  27 , and a spring clip  33  having a locking pin  34 . The cable assembly  32  passes through the button  30  and onward for connection to a pair of wedges  27  disposed near the lower ends of the arm members  26 ,  28 . The wedges  27 ,  29  are dimensioned to cooperate with a spring clip  33  disposed within each arm member  26 ,  28 . The spring clip  33  includes a locking pin  34  which is dimensioned to extend through an aperture formed along the outer wall of each arm member  26 ,  28 , as well as an aperture formed in the outer wall of the handle guides  14 ,  16 . 
     When the button  30  is not depressed, the wedges  27  will not be acting upon the spring clip  33  and thus the locking pins  34  will extending through aperture in the outer walls of the arm members  26 ,  28 . When the arm members  26 ,  28  are rotated into engagement with the handle guides  14 ,  16 , the locking pins  34  will also extend through the apertures in the outer wall of the handle guides  14 ,  16  (due to the spring force of the spring clip  33 ) to effectively lock the arm members  26 ,  28  to the handle guides  14 ,  16 . When the button  30  is depressed to overcome the internally biasing spring within the grip  24 , the cable assembly  32  will be forced into motion such that the cable assembly  32  pulls the wedges  27  into engagement with the spring clips  33 , which will retract the locking pins  34  into the interior of the arm members  26 ,  28  such that the arm members  26 ,  28  may be disengaged/unlocked from the handle guides  14 ,  16 . In this state, the handle assembly  12  may be rotated and stored within a recess formed in the back of the body of the stringed instrument, after which the neck of the stringed instrument may be folded. The handle guides  14 ,  16  each include a beveled section  36  that bows outwardly in a lateral direction from an outer side wall  42 . The beveled section  36  serves as an entry point for the locking pins  34  when the arm members  26 ,  28  are reengaging with the handle guides  14 ,  16 . The beveled section  36  temporarily deflects the locking pins  34  into the interior of the arm members  26 ,  28  before extending through the apertures in the handle guides  14 ,  16  to lock the arm members  14 ,  16  to the handle guides  14 ,  16 . 
     The actuator system  10  includes a pair of rails  46 ,  48  which cooperate with a floating tail piece assembly  50  and truss lock  52  to effect folding and unfolding of the fretted stringed instrument according to aspects of the present invention. The rails  46 ,  48  extend between the lower mounting plates  18 ,  20  and an upper mounting plate  54 . As best shown in  FIG.  4   , the lower mounting plates  18 ,  20  are equipped with shaft guides  19 , which loosely constrain the lower ends of the rails  46 ,  48 . The upper ends of the rails  46 ,  48  may be fixedly coupled to the upper mounting plate  54 , such as via a lock-nut or the like. The floating tail piece assembly  50  includes a pair of rollers  56 ,  58  dimensioned to engage with (and preferably roll along) the rails  46 ,  48  when the tail piece assembly  50  moves along the rails  46 ,  48 . The tail piece assembly  50  moves along the rails  46 ,  48  in two manners: 1) under compression from the truss lock  52 , which is used to position the tail piece assembly  50  such that strings (e.g. guitar strings) are elongated and tightened for tuning and instrument play; and 2) under tension of springs  60 ,  62  coupled to the upper mounting plate  54 , which occurs after the truss lock  52  is moved away from the tail piece assembly  50  and the tension of the instrument strings pulls the tail piece assembly  50  away from the upper mounting plate  54 . 
     The truss lock  52  is coupled to the handle guides  14 ,  16  via a pair of linkages  64 . Bolts  61 ,  63  are used to rotatably couple the linkages  64  to the handle guides  14 ,  16 , and bolts  65 ,  67  are used to rotatably couple the linkages  64  to the truss lock  52 . When the handle assembly  12  is locked within the handle guides  14 ,  16  (via pins  32 ,  34 ), the truss lock  52  will be forced into movement along the rails  46 ,  48  as the handle member  12  is rotated during use. A ram rod  68  is coupled to the truss lock  52  via a binding post assembly  70 . Although not shown, the ram rod  68  is coupled to one or more locking rods that serve to lock and unlock a mid-neck hinge assembly in the neck of the fretted stringed instrument. 
       FIGS.  8 - 10    (perspective views) and  FIG.  17 - 19    (side views) show the actuator assembly  10  in use during the process of rotating a handle assembly  12  from a stored state to retract the ram rod  62  and release the floating tail piece assembly  50 , which is the first phase of using the actuator assembly  10  to fold a fretted instrument according to aspects of the present invention. To do so, a user need simply use the grip  24  to pull the handle assembly  12  from the stored state within a recess formed in the back of the body of the stringed instrument. This forces the handle guides  14 ,  16  and the arm members  26 ,  28  into rotation about the binding posts  15  extending through the lower mounting plates  18 ,  20 . This moves the truss lock  52  along the rails  46 ,  48  away from the floating tail piece assembly  50 , due to the connection of the linkages  64 ,  66  which extend between the handle guides  14 ,  16  and the lateral ends of the truss lock  52 . The ram rod  62  is coupled to the truss lock  52  such that the ram rod  62  moves from the position shown in  FIG.  8    (fully extended) to that shown in  FIG.  10    (fully retracted). The ram rod  62  is coupled to locking pins (not shown) that serve to lock the hinge of the stringed instrument when in the fully extended state ( FIG.  8   ) and to unlock the hinge of the stringed instrument when in the fully retracted state ( FIG.  10   ). 
       FIGS.  11 - 12    (perspective views) and  FIGS.  20 - 21    (side views) show the actuator assembly  10  in use during the process of rotating the handle assembly  12  back to the stored state after disengaging with rotating handle guides  14 ,  16 , which is the second phase of using the actuator assembly  10  to fold a fretted instrument according to aspects of the present invention. To disengage or unlock the arm members  26 ,  28  from the handle guides  14 ,  16 , the button  30  is depressed (to overcome one or more internally disposed springs) to pull the ends of the cable assembly  32  upwards towards the grip  24 , which forces the wedges  27  into engagement with the spring clips  33  to retract the locking pins  34  such that the arm members  26 ,  28  may be disengaged/unlocked from the handle guides  14 ,  16 . In this state, the handle assembly  12  may be rotated and stored within a recess formed in the back of the body of the stringed instrument as shown in  FIG.  12   , after which the neck of the stringed instrument may be folded over the actuator assembly  10 . 
       FIGS.  13 - 14    (perspective views) and  FIGS.  22 - 23    (side views) show the actuator assembly  10  in use during the process of rotating the handle assembly  12  from the stored state to reengage with the rotating handle guides  14 ,  16 , which is the first phase of using the actuator assembly  10  to unfold a fretted instrument according to aspects of the present invention. The handle assembly  12  is pulled from the stored state ( FIG.  12   ) until the arm members  26 ,  28  are rotated into positioned within the handled guides  14 ,  16 . When this occurs, the locking pins  34  are forced into contact with the beveled section  36  of the handle guides  14 ,  16 . The contact between the beveled section  36  and the locking pins  34  overcomes the spring force of the spring clip  33  and thereby causes the locking pins  34  to retract within the arm members  26 ,  28  until the locking pins  34  are aligned with the apertures formed in the outer wall of the handle guides  14 ,  16 . When this co-alignment occurs, the locking pins  34  extend through the aperture formed in the outer walls of the handle guides  14 ,  16  to effectively lock the arm members  26 ,  28  within the handle guides  14 ,  16 . 
       FIGS.  15 - 16    (perspective views) and  FIGS.  24 - 25    (side views) show the actuator assembly  10  in use during the process of rotating the handle assembly  12  back to the stored state after reengaging with rotating handle guides  14 ,  16  to deploy the ram rod  62  and secure the floating tail piece assembly  52 , which is the second step of using the actuator assembly  10  to unfold a fretted instrument according to aspects of the present invention. Once the handle assembly  12  has been locked in place within the handle guides  14 ,  16 , a user may rotate the handle assembly  12  back towards the stored position of  FIG.  16   . Doing so will drive the truss lock  52  along the rails  46 ,  48  due to the operation of the linkages  64 ,  66  that extend between the handle guides  14 ,  16  and the truss lock  52 . The movement of the truss lock  52  along the rails  46 ,  48  will force the truss lock  52  into abutment with the floating tail piece assembly  50  such that the floating tail piece assembly  50  is moved along the rails  46 ,  48  towards the upper mounting plate  54 . The strings of the stringed instrument are anchored within the floating tail piece assembly  50  such that, when it is positioned as shown in  FIGS.  16  and  25   , the strings will be at full tension such that they can be tuned for play, typically with very minimal tuning required (e.g. less than 1 half step for guitars). Movement of the truss lock  52  also drive the ram rod  62  into the fully extended position ( FIG.  25   ) also serve to drive locking rods into the hinge of the stringed instrument such that the stringed instrument is ready for play. 
       FIGS.  26 A- 26 E  are various views of an upper mounting plate  54  forming part of the actuator assembly  10  of  FIGS.  1 - 7    according to aspects of the present invention. The upper mounting plate  54  includes a base  70  with a plurality of mounting holes  72  for coupling the upper mounting plate  54  to the base plate  22 , preferably via machine screws threaded into threaded apertures formed in the base plate  22 . A pair of first vertical tabs  74  extend from the base  70 , which each include an aperture  80  dimensioned to receive a first (threaded) end of the rails  46 ,  48 . The threads of the first ends of the rails  46 ,  48  engage into a nut or other capture mechanism (e.g. PEM stud with internal threads) disposed adjacent to or forming part of the vertical tabs  74 . A second pair of vertical tabs  78  extend from the base  70 , which each include a small aperture to engage the first end of the springs  60 ,  62  forming part of the floating tail piece assembly  50 . A third pair of tabs  82  extend from the base  70 , which collectively form a barrier for the upper edge of the floating tail piece assembly  50  when the truss lock  52  pushes it into the fully constrained state shown in  FIGS.  1 - 7   . 
       FIGS.  27 A- 27 D  are various views of a first lower mounting plate  18  forming part of the actuator assembly  10  of  FIGS.  1 - 7    according to aspects of the present invention. The first lower mounting plate  18  includes a first wall  84  and a second wall  86  disposed generally perpendicular to one another. The first wall  84  includes an aperture  88  dimensioned to receive a second (non-threaded) end of the rails  46 ,  48 . The second ends of the rails  46 ,  48  are dimensioned to have a degree of play relative to the apertures  88 , for example by being loosely constrained within the shaft guide  19  shown in  FIGS.  44 A- 44 C . A pair of mounting tabs  92 ,  94  extend from the bottom of the first and second walls  48 ,  86 , respectively. The mounting tabs  92 ,  94  include mounting apertures  96 ,  98 , respectively, for mounting the first lower mounting plate  18  to the base  22  (such as via machine screws threaded into threaded apertures formed in the base  22 ). The second wall  86  includes a side aperture  90  dimensioned to receive binding posts  15  ( FIG.  2   ) for the purpose of rotatably securing the handle guide  14  and arm member  26  to the first lower mounting plate  18 . 
       FIGS.  28 A- 28 D  are various views of a second lower mounting plate  20  forming part of the actuator assembly  10  of  FIGS.  1 - 7    according to aspects of the present invention. The second lower mounting plate  20  includes a first wall  84  and a second wall  86  disposed generally perpendicular to one another. The first wall  84  includes an aperture  88  dimensioned to receive a second (non-threaded) end of the rails  46 ,  48 . The second ends of the rails  46 ,  48  are dimensioned to have a degree of play relative to the apertures  88 , for example by being loosely constrained within the shaft guide  19  shown in  FIGS.  44 A- 44 C . A pair of mounting tabs  92 ,  94  extend from the bottom of the first and second walls  48 ,  86 , respectively. The mounting tabs  92 ,  94  include mounting apertures  96 ,  98 , respectively, for mounting the second lower mounting plate  20  to the base  22  (such as via machine screws threaded into threaded apertures formed in the base  22 ). The second wall  86  includes a side aperture  90  dimensioned to receive binding posts  15  ( FIG.  2   ) for the purpose of rotatably securing the handle guide  16  and arm member  28  to the second lower mounting plate  20 . 
       FIG.  29    is a perspective view of a floating tail piece assembly  50  forming part of the actuator assembly  10  of  FIGS.  1 - 7    according to aspects of the present invention. The floating tail piece assembly  50  includes a pair of elongated plates  100  mounted on either side of a tail piece  102  via a plurality of machine screws  106  (2 per plate  100 ). As shown in  FIGS.  30 A- 30 C , the elongated plates  100  include apertures to receive the machine screws  106  and also apertures to receive binding posts  108  for the purpose of rotatably mounting the rollers  56 ,  58  shown in  FIG.  29   . The rollers  56 ,  58  are dimensioned to roll along the lateral sides of the rails  46 ,  48 , which are positioned within a gap between the rollers  56 ,  58  and the tail piece  102 , as shown (by way of example only) in  FIG.  1   . The lower ends of the springs  60 ,  62  are mounted to the tail piece  102  and serve to exert a tension force on the floating tail piece assembly  50  to bias it towards the third pair of vertical tabs  82  of the upper mounting plate  54 . The tail piece  102  includes a plurality of apertures  103  (for example, six (6) for guitars) dimensioned to receive the bulbous ends of the instrument strings. When the floating tail piece assembly  50  is locked in place as shown in  FIGS.  1 - 7   , the tail piece  102  serves to anchor the instrument strings such that they may be tuned for play. When the floating tail piece assembly  50  is released (that is, when the handle assembly  12  is rotated to move the truss lock  52  away from the floating tail piece assembly  50 ), the tension on the strings will be significantly reduced (from fully tuned tension of 118 lbs. for guitar strings) and the floating tail piece assembly  50  will translate away from the upper mounting plate  54  along the rails  46 ,  48  as the springs  60 ,  62  elongate. In this state, the strings of the instrument will be at a reduced state (e.g. approximately 3-5 lbs. for guitar strings) such that the strings won&#39;t be kinked when they fold over the hinge of the neck of the stringed instrument. The springs  60 ,  62  will extend to accommodate the travel of the strings as they follow-the-fold over the neck hinge during the folding process. 
       FIGS.  31 A- 31 D  are various views of the truss lock member  52  forming part of the actuator assembly  10  of  FIGS.  1 - 7    according to aspects of the present invention. The truss lock member  52  includes a pair of rail bores  110  dimensioned to slidably receive and pass the rails  46 ,  48  such that the truss lock  52  may be translated along the rails  46 ,  48  under the direction of the handle assembly  12 . The truss lock  52  includes a mounting aperture  112  dimensioned to receive the binding post  70  for coupling the ram rod  62  to the truss lock  52 , as shown in  FIG.  1   . The truss lock  52  includes a pair of string aperture  114  dimensioned to pass the instrument strings from the tail piece assembly  50  in route to a string roller assembly (not shown) mounted to the base plate  22 , which in turn allows the strings to pass through an string aperture formed in the body of the instrument for eventual connection to tuning machines located on a headstock on the end of the neck of the instrument. The truss lock  52  includes a pair of side apertures  116  dimensioned to receive bolts  65 ,  67  for the purpose of rotatably mounting the linkages  64 ,  66  to the truss lock  52 . 
       FIGS.  32 A- 32 D  are various views of the linkage members  64 ,  66  forming part of the actuator assembly  10  of  FIGS.  1 - 7    according to aspects of the present invention. Each linkage  64 ,  66  includes a pair of mounting holes  90  and stiffening rib  118 . The mounting holes  90  are dimensioned to receive bolts  61 ,  63  for rotatably coupling the lower end of the linkages  64 ,  66  to the handle guides  14 ,  16 , and bolts  65 ,  67  for rotatably coupling the upper end of the linkage  64 ,  66  to the side apertures  116  of the truss lock  52 . The stiffening rib  118  is an indented section that provides additional structural rigidity to the linkage members  64 ,  66  to withstand the forces being transferred from the handle guides  14 ,  16  to the truss lock  52  due to the rotation of the handle assembly  12  when the arm members  26 ,  28  are engaged within the handle guides  14 ,  16 . 
       FIGS.  33 A- 33 E  are various views of the first handle guide  14  forming part of the actuator assembly  10  of  FIGS.  1 - 7    according to aspects of the present invention. The first handle guide  14  includes an outer side wall  120 , an inner side wall  122 , and a base  124  extending therebetween. The side walls  120 ,  122  are generally parallel to one another and spaced apart a sufficient distance to receive the arm member  26  of the handle assembly  12 . A pair of apertures  126  are formed along one end of the inner and outer side walls  120 ,  122 . The apertures  126  are dimensioned to receive the binding posts  15  to rotatably couple the handle guide  14  to the side aperture  90  of the second wall  86  of the lower mounting plate  18 , as well as to rotatably couple the arm member  26  within the handle guide  14 . The inner wall  122  includes a side aperture  128  dimensioned to receive bolt  61  for the purpose of securing the lower end of the linkage  64  to the handle guide  14 . The outer wall  120  includes a locking aperture  130  located adjacent to the beveled section  36 . The locking aperture  130  is dimensioned to receive the locking pin  34  of the spring clip  33  when the arm member  26  is fully rotated into position in between the walls  120 ,  122  of the handle guide  14 . As the handle assembly  12  is rotated towards the fully engaged position, the locking pin  34  of the spring clip  33  will come into contact with the beveled section  36  and progressively force the locking pin  34  into a retracted state within the arm member  26  until the locking pin  34  is aligned with the locking aperture  130 . When so aligned, the locking pin  34  will extend out of the locking aperture  130  under the force of the spring clip  33  to effectively lock the arm member  26  within the handle guide  14 . 
       FIGS.  34 A- 34 E  are various views of the second handle guide  16  forming part of the actuator assembly  10  of  FIGS.  1 - 7    according to aspects of the present invention. The second handle guide  16  includes an outer side wall  120 , an inner side wall  122 , and a base  124  extending therebetween. The side walls  120 ,  122  are generally parallel to one another and spaced apart a sufficient distance to receive the arm member  28  of the handle assembly  12 . A pair of apertures  126  are formed along one end of the inner and outer side walls  120 ,  122 . The apertures  126  are dimensioned to receive the binding posts  15  to rotatably couple the handle guide  16  to the side aperture  90  of the second wall  86  of the lower mounting plate  20 , as well as to rotatably couple the arm member  28  within the handle guide  16 . The inner wall  122  includes a side aperture  128  dimensioned to receive bolt  63  for the purpose of securing the lower end of the linkage  64  to the handle guide  16 . The outer wall  120  includes a locking aperture  130  located adjacent to the beveled section  36 . The locking aperture  130  is dimensioned to receive the locking pin  34  of the spring clip  33  when the arm member  28  is fully rotated into position in between the walls  120 ,  122  of the handle guide  16 . As the handle assembly  12  is rotated towards the fully engaged position, the locking pin  34  of the spring clip  33  will come into contact with the beveled section  36  and progressively force the locking pin  34  into a retracted state within the arm member  28  until the locking pin  34  is aligned with the locking aperture  130 . When so aligned, the locking pin  34  will extend out of the locking aperture  130  under the force of the spring clip  33  to effectively lock the arm member  28  within the handle guide  16 . 
       FIGS.  35 A- 35 E  are various views of the first arm member  26  forming part of the actuator assembly  10  of  FIGS.  1 - 7    according to aspects of the present invention. The arm member  26  includes a lower section  132  and an upper section  134 , which are both hollow in construction and angled relative to one another. The lower section  132  includes a pair of mounting apertures  126  dimensioned to receive the binding posts  15  to rotatably couple the arm member  26  within the handle guide  14 . The lower section  132  is dimensioned to receive the spring clip  33  ( FIGS.  39 A- 39 C ) and the wedge member  27  ( FIGS.  40 A- 40 D ), which form part of the system for selectively locking and unlocking the handle assembly  12  from the handle guides  14 ,  16 . The spring clip  33  is positioned within the lower section  132  such that the locking pin  34  extends through a locking aperture  138  formed in the outer wall of the lower section  132  due to the force of the spring clip  33 . The locking pin  34  may be retracted from or within the locking aperture  138  in two manners. First, the locking pin  34  may be retracted due to the operation of the button  30  of the handle assembly  12 , which serves to pull the wedge  27  upwards within the lower section  132  (via cable assembly extending between the button  30  and the wedges  27 ) until it overcomes the force of the spring clip  33  to remove the locking pin  34  from the locking aperture  138 . Second, the locking pin  34  may be forcibly pushed into the locking aperture  138  due to the beveled section  36  of the outer wall  120  of the handle guide  14  when the arm member  26  enters the handle guide  14  due to the rotation of the handle assembly  12  during the step of reengaging the handle assembly  12  to the handle guide  14  as shown in  FIGS.  13 - 14  and  22 - 23   . 
       FIGS.  36 A- 36 E  are various views of the second arm member  28  forming part of the actuator assembly  10  of  FIGS.  1 - 7    according to aspects of the present invention. The arm member  28  includes a lower section  132  and an upper section  134 , which are both hollow in construction and angled relative to one another. The lower section  132  includes a pair of mounting apertures  126  dimensioned to receive the binding posts  15  to rotatably couple the arm member  28  within the handle guide  16 . The lower section  132  is dimensioned to receive the spring clip  33  ( FIGS.  39 A- 39 C ) and the wedge member  27  ( FIGS.  40 A- 40 D ), which form part of the system for selectively locking and unlocking the handle assembly  12  from the handle guides  14 ,  16 . The spring clip  33  is positioned within the lower section  132  such that the locking pin  34  extends through a locking aperture  138  formed in the outer wall of the lower section  132  due to the force of the spring clip  33 . The locking pin  34  may be retracted from or within the locking aperture  138  in two manners. First, the locking pin  34  may be retracted due to the operation of the button  30  of the handle assembly  12 , which serves to pull the wedge  27  upwards within the lower section  132  (via cable assembly extending between the button  30  and the wedges  27 ) until it overcomes the force of the spring clip  33  to remove the locking pin  34  from the locking aperture  138 . Second, the locking pin  34  may be forcibly pushed into the locking aperture  138  due to the beveled section  36  of the outer wall  120  of the handle guide  14  when the arm member  28  enters the handle guide  16  due to the rotation of the handle assembly  12  during the step of reengaging the handle assembly  12  to the handle guide  16  as shown in  FIGS.  13 - 14  and  22 - 23   . 
       FIGS.  37 A- 38 F  are various views of a grip base  140  ( FIGS.  37 A- 37 F ) and a grip cover  150  ( FIGS.  28 A- 28 F ) forming the handle grip  24  of the actuator assembly  10  of  FIGS.  1 - 7    according to aspects of the present invention. Collectively, the grip base  140  and grip cover  150  provide a purchase point for a user to use the actuator assembly  10  (including the button  30  shown in  FIGS.  41 A- 41 D ) for loosening and tightening the strings, as well as unlocking and locking the hinge of the neck of the stringed instrument, for the purpose of folding and unfolding the stringed instrument via the steps shown in  FIGS.  8 - 25   . 
     As best shown in  FIG.  37 A , the grip base  140  is a molded part having a central channel  142 , end extensions  144 , a button aperture  146 , and a cable groove  148  extending along the middle of the central channel  142  on either side of the button aperture  146 . The end extensions  144  are dimensioned to fit into the open ends of the upper sections  134  of the arm members  26 ,  28  to secure the grip body  140  to the arm members  26 ,  28 , which fixation may be augmented via screws or the like extending through the wall(s) of the arm members  26 ,  28  and into the end extensions  144 . The button aperture  146  is dimensioned to slidably receive the button  30  of  FIGS.  41 A- 41 D . The cable groove  148  is dimensioned to slidably guide the top section of the cable assembly  32  of  FIG.  42   . The central groove  142  includes a plurality of screw housings  153 , which correspond to a plurality of screw housings  152  extending from the lower surface of the grip cover  150 , as best viewed in  FIGS.  38 A- 38 F . Each screw housing  152 ,  153  is dimensioned to receive a screw for the purposes of mounting the grip cover  150  to the grip base  140 . 
       FIGS.  39 A- 39 C  are various views of the locking spring clip  33  forming part of the actuator assembly  10  of  FIGS.  1 - 7    according to aspects of the present invention. The locking clip  33  includes a ramped section  154  and a base section  156 , which are contiguously formed from spring steel and configured to resist against any forces that act upon or otherwise bias the ramped section  154  towards to the base section  156 . The ramped section  154  has an elongated slot  158  dimensioned to pass the lower section of the cable assembly  32  during operation of the spring clip  33  in both modes of deformation. In the first mode, the cable  32  passes through the ramped section  154  when the spring clip  33  is deformed due to the wedges  27  moving under operation of the button  30  and the cable assembly  32 , which serves to disengage the arm members  26 ,  28  from the handle guides  14 ,  16  (as shown in  FIGS.  11 - 12  and  20 - 21   ). In the second mode, the cable  32  passes through the ramped section  154  when the spring clip  33  is deformed due to the beveled section  36  of the handle guides  14 ,  16  acting against the locking pins  34  when the arm members  26 ,  28  are introduced into the handle guides  14 ,  16  to lock the relative to one another (as shown in  FIGS.  13 - 14  and  22 - 23   ). 
       FIGS.  40 A- 40 D  are various views of the wedge member  27  forming part of the actuator assembly of  FIGS.  1 - 7    according to aspects of the present invention. The wedge member  27  includes a longitudinal bore  160  and a side channel  162  extending between a ramped surface  164  and the bore  160 . The longitudinal bore  160  and side channel  162  each extend the length of the wedge member  27 . The bore  160  includes a first section  166  and a second section  168 . The first second  166  has a cross sectional diameter dimensioned to receive a crimped end  180  on the terminal end of the cable  32  shown in  FIG.  42   . The second section  168  is dimensioned to receive the cable  32  but too narrow to receive the crimped end  180  of the cable  32 . To engage the cable  32  to the wedge  27 , the cable  32  is advanced along the outsider of the ramped surface  164  of the wedge  27  until the crimped end  180  extends past the wide end of the wedge  27 . The cable  32  can then be advanced laterally into the side channel  162  such that the crimped end  180  is moved over and then into the first section  166  of the bore  160 . In operation, the ramped surface  164  of the wedge  27  is dimensioned to slidably cooperate with the ramped section  154  of the spring clip  33  to selectively deform the clip  33  to remove the locking pin  34  from the handle guides  14 ,  16  to disengage the arm members  26 ,  28  from the handle guides  14 ,  16  (as shown in  FIGS.  11 - 12  and  20 - 21   ). 
       FIGS.  41 A- 41 D  are various views of the handle button  30  forming part of the actuator assembly  10  of  FIGS.  1 - 7    according to aspects of the present invention. The button  30  is molded and includes a base  170  and a button extension  172 . The base  170  includes a cable bore  174  that progresses from one lateral edge of the base  170  to the other lateral edge of the base  170 . The cable bore  174  is dimensioned to receive and pass the upper section of the cable  32  through the base  170  such that the cable will be moved along with the button  30  when the button extension  172  is moved within the button aperture  146 . By moving the cable  32  along with the button  30 , the crimped ends  180  of the cable assembly  32  will be moved upwards with the arm member  26 ,  28 , which forces the wedges  27  into engagement with the ramped section  154  of the spring clip  33  to remove each locking pin  34  from engagement with the handle guides  14 ,  16 . This enables the effective and quick release of the arm members  26 ,  28  from the handle guides  14 ,  16  (as shown in  FIGS.  11 - 12  and  20 - 21   ). 
       FIG.  42    is a perspective view of the cable assembly  32  forming part of the actuator assembly  10  of  FIGS.  1 - 7    according to aspects of the present invention. The cable  32  includes an upper section  176  and two lower sections  178 , each of which terminates with a crimped end  180 . When assembled with the handle assembly  12 , the upper section  176  extends through the aperture  174  of the base  170  of the button  30 , which is positioned within the button aperture  146  of the grip base  140 . The lateral portions of the upper section  176  are positioned within the central guide  148  of the grip base  140  and pass through apertures formed in the end extensions  144  of the grip base  140  such that the lower sections  178  extend downward within the interior of the arm members  26 ,  28 . The crimps  180  are applied to at least one of the terminal ends of the cable  32  after passing through the grip base  140 . Before the grip cover  150  is mounted to the grip base  140 , one or more compression springs are positioned to cooperate with the button  30 . The grip cover  150  may then be mounted to the grip base  140 , which involves placing the grip cover  150  over the central channel  142  and inserting screws through the screw housings  152  of the grip cover  150  and the screw housings  153  of the grip base  140 . The grip cover  150  forms an abutment for the compression spring(s) that cooperate with the button  30 . To release the handle assembly  12  from the handle guides  14 ,  16 , a user may simply use one or more fingers to depress the button extension  172  within the button aperture  146  of the grip base  140 . This will cause the internally disposed compression springs to compress, which in turn will draw the lower sections  178  of the cable  32  upward within the arm members  26 ,  28 . This forces the wedges  27  into abutment with the ramped section  154  of the spring clip  33 , which removes the locking pin  34  of the spring clip  33  from the locking aperture  130  of the handle guides  14 ,  16  to release the handle assembly  12  from the handle guides  14 ,  16 . 
       FIGS.  43 A- 43 C  are various views of the shafts or rails  46 ,  48  forming part of the actuator assembly  10  of  FIGS.  1 - 7    according to aspects of the present invention. The rails  46 ,  48  each include a smooth central section  182  extending between a threaded end  184  and a keyed end  186  having flat upper and lower surfaces. The rails  46 ,  48  extend between the upper mounting plate  54  (tabs  74 ) and the lower mounting plates  18 ,  20 , respectively. The smooth central section  182  is dimensioned to interact with the rollers  56 ,  58  of the floating tail piece assembly  50 , as well as the rail bores  110  of the truss lock  52 , to allow both structures to translate or otherwise move up and down within the actuator assembly  10 . Movement of the truss lock  52  along the rails  46 ,  48  occurs due to the rotation of the handle assembly  12  when engaged with the handle guides  14 ,  16 . Movement of the floating tail piece assembly  50  along the rail  46 ,  48  occurs due to the movement of the truss lock  52  (when the handle assembly  12  is engaged with the handle guides  14 ,  16 ) and due to the forces exerted upon the translating tail piece assembly  50  by the strings of the instrument and the springs  60 ,  62 . The threaded end  184  of the rails  46 ,  48  are fixedly coupled to the upper mounting plate  54  by passing each through the apertures  80  and threading on a lock-nut or the like. The keyed end  186  is loosely retained by the lower mounting plates  18 ,  20  by passing each through the apertures  88  and into the shaft guide 
       FIG.  44 A- 44 C  are various views of the shaft guides  19  forming part of the actuator assembly  10  of  FIGS.  1 - 7    according to aspects of the present invention. The shaft guide  19  includes a base  190 , an extension  192 , and a shaft bore  194  extending therethrough. The extension  192  is press fit into the apertures  88  of the lower mounting plates  18 ,  20  such that the base  190  extends away from the main part of the actuator assembly  10 . The shaft bore  194  is dimensioned to retain the keyed end  186  of the rails  46 ,  48 , yet in a semi-constrained manner (vs. rigidly). Providing this semi-constrained engagement between the lower end of the rails  46 ,  48  will facilitate the translation of the floating tail piece assembly  50  and the truss lock  52  and prevent or minimize the likelihood of any jamming or misalignment. 
       FIGS.  45 - 54    illustrate the foldable stringed instrument  200  in the folding and unfolding process according to aspects of the present invention.  FIGS.  47 - 51    show the folding process, whereby the actuator  10  is disengaged to allow the neck  202  to be positioned within the back recess  206  of the body  204 .  FIGS.  52 - 54    show the unfolding process, whereby the actuator  10  is reengaged after the neck has been fully extended such that the strings can be return to the fully tensioned, playable state. 
     Any of the features or attributes of the above the above described embodiments and variations can be used in combination with any of the other features and attributes of the above described embodiments and variations as desired. From the foregoing disclosure and detailed description of certain preferred embodiments, it is also apparent that various modifications, additions and other alternative embodiments are possible without departing from the true scope and spirit. The embodiments discussed were chosen and described to provide the best illustration of the principles of the present invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the present invention as determined by the appended claims when interpreted in accordance with the benefit to which they are fairly, legally, and equitably entitled.