Patent Publication Number: US-6710234-B2

Title: Stringed musical instrument incorporating an adjustable string tree

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This is a continuation of U.S. patent application Ser. No. 09/709,165, filed Nov. 8, 2000, now U.S. Pat. No. 6,515,207, which is a continuation-in-part of U.S. patent application Ser. No. 29/122,909, filed May 5, 2000, now U.S. Pat. No. D441,006. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to musical instruments and more particularly to accessories for stringed instruments, the present invention being an adjustable string tree. 
     2. Description of the Related Art 
     As indicated by the underlying U.S. patent application Ser. No. 09/511,878 filed on Feb. 25, 2000 entitled Improved Stringed Musical Instruments And Method Therefor, string trees, or string retainers, may be used in order to selectively create nodes for vibrating strings as well as controlling the tension on such strings. In that underlying application, static, or non-adjustable, string trees were disclosed and described for use in the musical instruments also described therein. Further development has provided additional advancements in the art, such that string trees may be made adjustable, and not just formed in a static, or non-adjustable manner. 
     In the prior application, the height of the string tree must be selected in advance in order to properly tension the string, making more complex the proper adjustment of the string by use of the string tree. Not only the height must be considered, but also the positioning of the string tree. Generally, the location of the string tree is chosen first in order to establish a node for the string portions resonating upon the plucking or driving of the string. The appropriate height is then determined in order to conform the string to the proper geometry/path in order to achieve the proper tension. 
     Due to the lack of adjustability and height, string trees such as those set forth in the underlying application have inherent limitations that are better addressed by an adjustable string tree. Such an adjustable string tree would advantageously operate in conjunction with current musical instruments, such as an electric guitar, without impeding or obstructing musical performance. Such adjustable string trees would advantageously be predictable in nature so as to provide consistent results no matter what type of string was retained by the string tree. 
     SUMMARY OF THE INVENTION 
     The present invention provides an adjustable string tree that efficiently uses minimal components in order to provide string retention, tension adjustment, and node establishment. 
     A unified base plate and back plate member may be affixed to a structure on a stringed instrument, such as the headstock on an electric guitar. A vertically adjustable top or upper plate adjustably slides vertically while being held in place horizontally with respect to the base plate. An adjustment bolt, in conjunction with a compression spring, serves to hold the adjustable top plate in place. The top plate engages the string to be retained and allows the musician or musical technician to adjustably control the tension on a string by moving the top plate vertically, with upwards motion generally releasing tension on a string and downward motion generally increasing tension on a string. 
     In an alternative embodiment, horizontal adjustment of the adjustable string tree may be achieved by a rail or other similar system that provides selectable adjustment of the placement of the adjustable string tree of the present invention along the path of the string to be retained. 
     By providing the adjustable string tree of the present invention, string tension may be selectably adjusted and node placement selectably established. 
     OBJECTS OF THE INVENTION 
     It is an object of the present invention to provide an adjustable string tree for musical instruments. 
     It is another object of the present invention to provide adjustable tension for strings in a musical instrument. 
     It is yet another object of the present invention to provide selectable nodes for musical instruments. 
     It is yet another object of the present invention to provide selectably adjustable nodes for stringed musical instruments. 
     It is yet another object of the present invention to provide adjustable string tension for selectable nodes of a stringed musical instrument. 
     It is yet another object of the present invention to provide a retrofittable means by which selectable nodes may provide adjustable string tension. 
     These and other objects and advantages of the present invention will be apparent from a review of the following specification and accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a top right perspective view of a top plate used in the present invention. 
     FIG. 2 is a top right perspective view of the adjustable string tree of the present invention showing adjustment of the top plate in phantom in conjunction with a string so adjusted, also in phantom. 
     FIG. 3 shows a top right perspective view of an alternative embodiment of the adjustable string tree of the present invention in a position generally corresponding to that of the upper plate as shown in phantom in FIG. 2, the top plate having a groove or indentation to accommodate the string. 
     FIG. 4 shows a top plan view of a headstock of a guitar, such as an electric guitar, with the adjustable string tree of the present invention in place. 
     FIG. 5 shows a side elevational view of the adjustable string tree as generally indicated in FIG.  2 . 
     FIG. 6 shows a side elevational view of the adjustable string tree as generally shown in FIG. 2 with the upper plate in a position generally corresponding to that shown in phantom in FIG. 2, and structures underlying the adjustable string tree shown in partial cutaway view. 
     FIG. 7 is a front plan view of the adjustable string tree shown in FIG.  6 . 
     FIG. 8 is an enlarged view of an alternative embodiment of the adjustable string tree as shown in FIG. 2 with the upper plate having a concave indentation to accommodate the string and downward motion of the upper plate shown in phantom, the string engaged by the upper plate shown in phantom in the upper and lower positions. 
     FIG. 9 is a rear plan view of the adjustable string tree of FIG.  8 . 
     FIG. 10 is a front elevational view of the adjustable string tree of FIG.  8 . 
     FIG. 11 is a top plan view of the adjustable string tree shown in FIG.  8 . 
     FIG. 12 is a right side plan view of the adjustable string tree as shown in FIG. 8, with the left side being a mirror image thereof. 
     FIG. 13 is a bottom plan view of the adjustable string tree of FIG.  8 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT(S) 
     The detailed description set forth below in connection with the appended drawings is intended as a description of presently-preferred embodiments of the invention and is not intended to represent the only forms in which the present invention may be constructed and/or utilized. The description sets forth the functions and the sequence of steps for constructing and operating the invention in connection with the illustrated embodiments. However, it is to be understood that the same or equivalent functions and sequences may be accomplished by different embodiments that are also intended to be encompassed within the spirit and scope of the invention. 
     As shown in FIGS. 2 and 8, the adjustable string tree  100  of the present invention has a top plate  102  and a unified base plate/back plate structure  104 . 
     The top plate  102  slidably engages the integrated base plate/back plate structure  104  in order to adjustably provide vertical positioning and tension upon a string S. The integrated base plate/back plate structure  104  is attached to a headstock H as shown in FIG. 4 as for an electric, acoustic, or other guitar or other stringed instrument. 
     As shown in FIG. 1, the top plate  102  has a front plate  120  that engages a string S at its distal end  122 . Generally, such engagement of a string S is on the underside  124  of the front plate  120 . A hole or aperture  130  may be present in the top plate  102  in order to provide for threadable adjustment to the top plate  102 . Threadable adjustment of the top plate  102  may be achieved in two ways, with the adjustment bolt or screw  132  threading into the base plate  110  and taking the top plate  102  with it or, alternatively, the threaded adjustment bolt  132  threadably engaging the top plate  102  and controlling the disposition of the top plate  102  relative to the base plate  110 . For the latter case, the adjustment bolt  132  would not screw into the base plate  110 , but would turn upon the base plate  110 . The threaded engagement between the adjustment bolt  132  and the top plate  102  then causes the top plate  102  to move with respect to the base plate  110  as the top plate  102  slides with respect to the back plate  112 . 
     As shown in FIG. 1, a T-shaped section  140  projects rearwardly from the front plate  120  and defines two mortises  142 ,  144  oppositely opposed on either side of a tenon  146  forming the upright portion of the T in the T-shaped section  140 . The top portion  148  of the T-shaped section generally matches that of the front plate  120  of the top plate  102 . The top portion  148  of the T-shaped section  140  is separated at its lateral ends by the mortises  142 ,  144  from the front plate portion  120  of the top plate  102 . 
     As shown in FIG. 2, the integrated base plate/back plate structure  104  has a base plate  110  fixed at generally a right angle to the back plate  112 . As for the top plate  102 , the base plate  110  and back plate  112  are generally formed of strong metal such as steel or the like, including carbon steel, which may be powder coated or otherwise for a more pleasing appearance. Alternatively, softer metals may allow for additional cosmetic enhancements and, depending on the required stress tolerances and operating conditions, may provide adequate support for the adjustable string tree  100  of the present invention. 
     As shown in FIG. 2, the base plate  110  may have a hole  150  through which a screw may fit in order to attach the base plate to a headstock H (FIG. 4) or other portion of a musical instrument. Alternative means other than screws might be used in order to fix the base plate  110  to the musical instrument. 
     FIGS. 6 and 7 show one embodiment of the present invention showing a screw  152  descending into a portion of the instrument to engage the instrument and hold the base plate  110  firmly in place. A screw hole  150  may be generally centrally located along the base plate  110  in a forward section thereof. In one embodiment, the screw hole  150  may be generally below a preferred area of the front plate  120  used to engage the string S. Under such circumstances, the string S would then be generally over the screw  152  and screw hole  150 . 
     The base plate  110  has a second bolt hole  154  (FIG. 13) generally in alignment with the top plate aperture  130 . In being so aligned with the top plate aperture  130 , the bolt hole  154  of the base plate  110  allows for the use of an adjustment bolt  132  to pass through both the top plate  102  and the base plate  110 . As shown in FIGS. 6 and 7, in one embodiment, the bolt hole  154  may allow the passage of the adjustment bolt  132  through the base plate  110 . In other embodiments, the bolt hole  154  may serve as a means by which the turning end of the adjustment bolt  132  may be allowed to articulate rotationally in a fixed position. This would then allow an adjustment bolt  132  in threaded engagement with the top plate  102  to vertically adjust the top plate  102  and the tension exerted against a string S. Under such conditions, the adjustment bolt  132  would not descend with the top plate  102 . 
     The back plate  112  generally has a lower upright supporting section  160  from which two vertical posts or tenons  162 ,  164  extend upwardly and away from the lower upright supporting section  160 . Defined between the two tenons  162 ,  164  is a mortise or gap  166  into which the tenon  146  of the T-shaped section  140  slidably fits. 
     The configuration between the mortise and tenons present in the top plate  102  and the back plate  112  provide reliable means by which the top plate  102  may slidably and adjustably engage the back plate  112 . This slidable engagement is achieved by the use of complementing mortise and tenon sets, one set disposed vertically and one set disposed horizontally. This fixes the top plate  102  in position with respect to the back plate  112  as well as the base plate  110 . 
     The horizontal mortise and tenon set may generally be considered that to be of the tenon  146  of the T-shaped section  140  in conjunction with the mortises  142 ,  144  present in the top plate  102 . The back plate  112  provides a vertical mortise and tenon set with the vertical tenons  162 ,  164  on either side of the vertical mortise  166 . These mortise and tenon sets, coupled with the top portion of the T-shaped section  140  as well as the front plate  120  of the top plate  102 , serve to prevent horizontal movement of the top plate  102  with respect to the back plate  112  and the integrated plate structure  104 . 
     The top plate tenon  146  slidably travels through the back plate mortise  166  in order to provide vertical adjustment to the top plate  102 . The vertical tenons  162 ,  164  travel through the horizontal mortises  142 ,  144  of the top plate  102 . Motion of the top plate  102  is restrained by the adjustable bolt in conjunction with the compression spring  170 . 
     The compression spring  170  provides an upward bias to the top plate  102 . The upward travel of the top plate  102 , as urged by the compression spring  170 , is obstructed by the head or other part of the adjustment bolt  132 . By the use of the opposing tensions between the upwardly biasing compression spring  170  and the downwardly restraining adjustment bolt  132 , the top plate  102  is generally held in place with respect to the top plate  102 . This stable structure is enhanced by the upward urging of a string S under tension by the top plate  102 . 
     As shown in FIGS. 5,  3 ,  8  and  12 , an alternative embodiment of the present invention provides an indentation  180  into which the string S may fit and be positively retained by the top plate  102 . The indentation  180  serves to better retain the string S in association with the top plate  102 . This allows the string S to undergo more activity, such as vibration, while still being retained by the top plate  102 . It also prevents the string as from disengaging the top plate  102  and becoming free from the retention of the adjustable string tree  100 . In an alternative embodiment, a protrusion, or ridge (not shown), may also be used to engage the string S. 
     In an alternative embodiment not shown in the drawings, a rail or other structure may provide a framework by which the adjustable string tree  100  of the present invention may engage the headstock H or other portion of a musical instrument adjacent musical strings. This would provide for the lateral or horizontal movement of the adjustable string tree in a selectable manner such that the placement of the node created by the adjustable string tree may be also adjusted. Such a framework would be in a path generally the same as that taken by a string to be engaged by the adjustable string tree. A selectable and adjustable locking mechanism may serve to hold the adjustable string tree in place upon the selection of a node position. The adjustable string tree could then be used to vertically adjust the top plate  102  and the corresponding tension on the adjacent string S. 
     While the present invention has been described with regards to particular embodiments, it is recognized that additional variations of the present invention may be devised without departing from the inventive concept.