Patent Publication Number: US-2015075351-A1

Title: Stringed Instrument Improvement

Description:
This application claims priority to U.S. provisional application 61/838,338 filed Jun. 23, 2013 by the same applicant. 
     This application is a continuation in part of U.S. non-provisional application Ser. No. 13/494,007 filed Jun. 11, 2012 by the present applicant, issued Aug. 5, 2014, as U.S. Pat. No. 8,796,524, which was a continuation in part of U.S. non-provisional application Ser. No. 13/424,357 filed Mar. 19, 2012 by the present applicant, and which claimed priority to U.S. provisional application 61/454,495 filed Mar. 18, 2011 by the same applicant. 
     The disclosure of this application incorporates by reference the entirety of said U.S. application Ser. No. 12/842,028 filed Jul. 22, 2010, U.S. provisional application 61/529,910 filed Aug. 31, 2011, U.S. non-provisional application Ser. No. 13/494,007 filed Jun. 11, 2012, U.S. non-provisional application Ser. No. 14/085,790 filed Nov. 20, 2013, U.S. non-provisional application Ser. No. 14/325,305 filed Jul. 7, 2014, and U.S. Pat. No. 8,796,524 issued Aug. 5, 2014. 
     The disclosure of this application is also supplemented by incorporation by reference to every claim previously submitted during prosecution of the said U.S. applications Ser. Nos. 12/842,028 and 13/494,007. 
     Said incorporation by reference shall supplement the present disclosure without in any way limiting the scope or meaning of the disclosure or claims of the present application or subsequent applications. 
    
    
     FIELD OF INVENTION 
     The present invention relates to devices which enhance the expressive qualities of a stringed musical instrument by empowering the artist to “bend” notes and chords in a harmonic manner. 
     SUMMARY 
     The application discloses various embodiments having guides adjustably fixed relative to a pivoting tailpiece, causing the strings to be stretched or relaxed when the tailpiece is rotated, enabling maintenance of relative pitch among strings. 
     The application discloses dual axis control, enabling a musician to sweep easily from “bend” to “dive” (sharp to flat) while using the muscles on only one side of the hand and wrist. Dual axis control further allows biasing a tailpiece against a separate stop on a separate axis after either a bend or a dive, with enhanced stability at neutral pitch, and requiring no locking mechanism. 
     The application discloses various embodiments of a cam-enabled return spring to maintain neutral tuning when the device is released without adversely affecting motion of the device. 
     Embodiments also include a beneficial combination of pitch-relative and non-pitch-relative vibrato means, where a non-pitch-relative vibrato displacement may be used to compensate for non-linearities in string tension while transposing over large spans. 
     Also disclosed are various embodiments enabling improved electronic control, improved limitation on string stress, improved float about a neutral position, improved flex compensation, improved string anchoring, improved fulcrum support, and improved bending means for individual strings. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIGS. 1 through 11  are perspective views of various embodiments of a neck mount bracket. 
         FIG. 12  is an end view of an embodiment of a guitar body and neck connected by a bracket. 
         FIG. 13  is an bottom view of an embodiment of a guitar body and neck connected by a bracket. 
         FIG. 14  is an end view of an embodiment of a guitar body and neck connected by a bracket. 
         FIG. 15  is an bottom view of an embodiment of a guitar body and neck connected by a bracket. 
         FIG. 16  is a cross sectional end view of an embodiment of a guitar body and neck connected by a bracket including keying means. 
         FIG. 17  is an bottom view of an embodiment of a guitar body and neck connected by a bracket including keying means. 
         FIG. 18  is a side view of an embodiment of a fretboard extender. 
         FIG. 19  is a side view an embodiment of a body, neck, and fretboard extender connected to an embodiment of a bracket. 
         FIG. 20  is a side view an embodiment of a body and neck connected to an embodiment of a bracket. 
         FIG. 21  is a side view an embodiment of a body and neck connected to an embodiment of a bracket. 
         FIG. 22  is a side view of an embodiment of a fretboard extender. 
         FIGS. 23 and 24  are side views of vibrato means having tension limiting means for one or more strings. 
         FIGS. 25A and 25B  are end and bottom views of an instrument with a substantially flat (preferably a high modulus composite) plate keyed on two edges into an instrument body, secured for example by adhesive means 
         FIG. 26A  shows an end view of an embodiment of a vibrato control arm having a rotational axis substantially parallel to the stings, where the body is cutaway to show an embodiment of vibrato connection and biasing means. 
         FIG. 26B  show a top view of an embodiment of a vibrato control arm having a rotational axis substantially parallel to the stings, and of drum on an axis substantially parallel to the strings for manipulating an electronic rotation sensor. 
         FIG. 26C  shows an end view of an embodiment of a vibrato control having a rotational axis substantially parallel to the stings, where the control comprises at least a partially arcuate surface. 
         FIG. 26D  shows an end view of an embodiment of a vibrato control having a rotational axis substantially parallel to the stings, where the control arm comprises a substantially planar surface 
         FIG. 26E  is a top view of an embodiment substantially similar to that of  FIG. 26B . 
     
    
    
     DISCUSSION 
     Parallel Control Axis 
       FIGS. 26A and 26B  illustrate an example where the pivot means is a shaft  113   a  rotating on axis  113 , preferably substantially below and parallel to the strings. An arm  16 , preferably curved to provide suitable neck and body clearance, radiates from said shaft, having a handle  16   c,  also preferably parallel the strings  4 . 
     The shaft engages the vibrato unit by suitable means, for example by a connecting rod  42  pivoting on crank arm  16   a  extending from the shaft  113   a,  and attached to a moveable member  8 , as illustrated in  FIG. 26A . 
     The device may utilize any biasing means, e.g. simple bias springs (not shown) connecting the rotating member  8  or a crank from shaft  113   a  to the instrument body  25 . 
     In the example shown in  FIG. 26A , the biasing means for the vibrato rotating member  8  is provided by return spring  56  pressing cam follower  55 . 9  toward cam  55 , also rigidly attached to shaft  113   a.  The angle of contact of the cam with the follower is preferably adapted generate forces opposes to the string tension Preferably a slight change in angular contact at the neutral position provides tuning stability when the return spring  56  is properly adjusted, as previously disclosed. 
     The cam follower  55 . 9  rotates on a shuttle  56   a  (or alternatively a rocker) providing stable contact between cam  55  and cam follower  55 . 9  by confining the cam follower to a linear or arcuate path, and resisting unwanted tangential motion of cam follower about the cam. 
     The actuation arm  16   c,  substantially parallel to the strings in  FIGS. 26A and 26B  may alternatively have the shape of a cylindrical control surface (not shown), preferably coaxial with shaft  113   a,  and of sufficient radius and surface friction to enable a rolling action with the palm side of the fingers while playing. 
     In examples of alternative embodiments, the combination of arm  16 , shaft  113   a,  and handle  16   c,  take the form of a full or partial drum surface as in  FIG. 26C , or a contoured or substantially planar surface (for example a pickguard) hinged along an axis substantially parallel to the strings, as in  FIG. 26D . 
     In alternative embodiments, the biasing means includes a cam and follower, at least one of which is moveable relative to a base, where rotation of the arm  16  is associated with relative motion of said cam and cam follower, such that rotating the arm  16  in one direction (preferably downward, away from the strings) alters the bias position of the main member  8  in a direction of increased bias spring force, for example similar to the device described with respect to  FIG. 9C . Shaft  113   a  may connect directly or indirectly to said one or more cam, and may be configured to bend or swivel or link to intermittent arm or shaft means. 
     Bend Limiter 
     In the embodiments of  FIGS. 23A and 23B  a separately biased guide crank  220  is provided for at least one sting. It preferably rotates on a common axis  1  with main rotating member  8 , and rests against a stop  222  relative to main member  8 . As main member  8  rotates in a bend direction, guide crank  220  rotates with it under the force of separate bias spring  122 , until preferably adjustable (by an adjusting screw, for example) stop  221  engages base  8 . In the example, crank  220  comprises string anchor means  10 , for example a slot positioned to enable string  4  to wrap over the surface of guide  6 . In a preferred embodiment, a quickly changeable adjuster, for example a sloped or stepped axial cam  221   a  in  FIG. 23A  between stop  221  and base  69  (pivotable about an axis  221   x ), enables a user to quickly select from among  2  or more bend limits during a performance. The range of adjuster  221   a  preferably is sufficient to enable adjusting the limit to totally prevent bend (sharpening) motion of crank  220  relative to base  69 . Adjuster  221   a  preferably comprises knob or lever means as shown to enable quick adjustment. 
     The separate crank  220  preferably includes string anchor means separate from the main member, for example a slot for receiving the ball end of a string, as shown, preferably far enough from the guide  6  to isolate the guide from the stiffness of ball end lashing. Main member may optionally be partially biased by separate balancing spring  40 . 
     The radius of guide  6  from axis  1  may be adjustable, for example by set screws on a flexible guide bracket  220 , as illustrated in  FIG. 23C , or it may be fixed, for example as illustrated in  FIG. 23A . A single fixed guide permits all other guides to be adjusted relative to the fixed guide to accomplish tuning of the device. Actuation effort may be adjusted by modifying the purchase of the actuator mechanism between the control arm and main member (not shown). 
     Neck Mounts 
     The application describes embodiments of a bracket and a method for connecting, a neck (in the prior to a guitar body in a manner leaving room for placement of the thumb of the fretting hand under the neck in the area of the connection. 
       FIGS. 1 through 5  show embodiments of a bracket having a base  1 , web  2 , and front and rear flanges  3   a  and  3   b.  In  FIG. 15  flanges  3   a  and  3   b  stabilizing the neck  14  by connecting it in a triangular pattern along a heel cut  17   a  and a longitudinal cut  18   a  in the forward most portion  18  of the body  15 . Fasteners  9   f  in the figure secure the bracket to the body, while fasteners  9   n  (typically wood screws or machine screws) connect the neck to the bracket. 
     The bracket is preferably fabricated, cast, or assembled from high modulus material for example steel, aluminum, titanium, or carbon composite. 
     The higher modulus at the bracket allows a thin base on the order of 6 mm. 
     Alternative embodiments in  FIGS. 6 through 11  utilize shoulders  4   a  and  4   b  or keys  5  (for example rectangular keys or discs) fitted to matching surfaces of the body. Keys may be stabilized to the bracket by, for example, pins  7 , recess  8 , precision screw shaft  6 , or welding or press fit. 
     In the various figures, flanges  3   a  and  3   b,  or shoulders  4   a  and  4   b,  or keys  5 , are preferably configured to mate with opposing surfaces on the guitar body in an orientation opposing motion in at least one direction normal to the face of the body  15 . 
     An optional neck heel stop la also optionally supports an optional cantilevered fretboard extender  11 , preferably connected by one or more screws. Height and angle of adjuster  11  may be adjusted by shims, machinable feet  12   a,  or setscrew feet  12   b.  Extender  11 , preferably aluminum, includes frets  11   a,  preferably cast or machined into the extender. 
     In an alternative embodiment shown in  FIGS. 23A and 23B , a single plate  1  of preferably a high modulus composite material (for example carbon-epoxy) is adhesively secured into keyways at the end and one side of the neck pocket of body  15 . The plate is preferably molded or predrilled with holes for attachment to a neck, the holes preferably used in locating the plate in an assembly jig for adhesive bonding to the body.