Abstract:
Neck truing devices may include a first member that is adapted to be fixedly embedded within the neck of a stringed instrument. A second member may be coupled to the first member and connected across both ends of the first member. An adjusting mechanism may be operable to selectively apply a first force to the first member via the second member in order to correct warpage of the neck in a first direction and a second force to the first member via the second member in order to correct warpage of the neck in a second direction.

Description:
This application claims priority to Japanese patent application number 2001-211005 filed Jul. 11, 2001, the contents of which are hereby incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present invention relates to truing devices for correcting warpage of necks of stringed instruments and, more particularly, to guitars equipped with such truing devices. 
     2. Description of the Related Art 
     When stings are tightened on the neck of a guitar, the guitar neck may warp or bend toward the front side of the guitar due to the tension of strings. In order to correct or eliminate such warpage of the neck, neck truing devices have been proposed. FIGS.  8 (A) to  8 (D) show a known neck truing device  50  that may be disposed within a longitudinal recess S formed in a neck body M of a neck N of a guitar so as to extend along the longitudinal direction of the neck N, as shown in FIG.  8 (E). 
     Referring to FIGS.  8 (A) to  8 (D), the known neck truing device  50  includes a first bar-shaped member  52  having a substantially U-shaped cross section. A second bar-shaped member  54  is disposed within the first bar-shaped member  52  and serves as a core. A stopper  54   s  is formed at the forward end (left end as viewed in FIG.  8 (A)) of the second bar-shaped member  54  and is disposed externally of the forward end of the first bar-shaped member  52 . A nut  56  is fitted into the rear end portion of the first bar-shaped member  52 , so that the nut  56  can rotate relative to the first-bar-shaped member about the longitudinal axis. A female thread  56   w  is defined within the nut  56 . A male thread  54   m  is defined on the base end portion of the second bar-shaped member  54  and threadably engages the female thread  56   w . A plate  58  is disposed between a bottom surface  52   b  (upper surface as viewed in FIG.  8 (A)) of the U-shaped groove defined within the first bar-shaped member  52  and an upper surface of the second bar-shaped member  54 . As shown in FIG.  8 (C), the second bar-shaped member  54  is partially curved or bent before the device  50  is disposed within the neck N. 
     According to this known arrangement, when an operator tightens the nut  56 , a tensile force is produced and is applied to the second bar-shaped member  54  due to the threaded engagement of the male thread  54   m  and female thread  56   w . As a result, the second bar-shaped member  54  causes the first bar-shaped member  52  to curve upwards from the position shown in FIG.  8 (C) by cooperating with the plate  58  (See FIG.  8 (D)). As shown in FIG.  8 (E), the device  50  is embedded along the longitudinal recess S of the neck N such that the bottom surface  52   b  of the U-shaped groove of the first bar-shaped member  52  is positioned on the front side (upper side of as viewed in FIG.  8 (E)) of the neck N. A finger board F is attached to the neck N, so that the device  50  is fixedly enclosed within the neck N. Therefore, by adjusting the degree of curvature of the first bar-shaped member  52  by means of the nut  56 , it is possible to correct warpage of (i.e., true or straighten) the neck N, which warpage may be caused due to the tension applied across the neck N by the strings. 
     The curvature of the first bar-shaped member  52  of the known neck truing device  50  can be varied in one direction by tightening the nut  56  in order to cope with the warpage of the neck N caused by the tension of the strings. However, the device  50  cannot cope with warpage in other directions. For example, depending on the condition of the material of the neck N (typically, the neck N is made of wood), the neck N may possibly warp toward the rear side of the guitar against the tension of the strings applied to the neck N. In such cases, the known truing device  50  cannot correct warpage of the neck N. 
     SUMMARY OF THE INVENTION 
     Therefore, it is one object of the present teachings to provide improved devices for correcting warpage of necks of stringed instruments. For example, in one aspect of the present teachings, neck truing devices may include a first member that is adapted to be fixedly disposed within the neck of the string instrument. A second member may be coupled to the first member and may be connected between or across the respective ends of the first member. An adjusting mechanism may serve to apply a first force and a second force to the first member via the second member in order to respectively correct the warpage of the necks in opposing directions. According to the present specification, the term “truing” is intended to mean adjusting or restoring the neck to a desired mechanical accuracy or form. If the neck of the stringed instrument is normally straight, then the neck truing device may be utilized to straighten the neck, if the neck has warped. However, the necks of some stringed instruments are normally curved. Thus, in such cases, the neck truing device may be utilized to return the neck to the desired curved configuration. 
     In one embodiment of the present teachings, the first member may be bent in a first direction when the first bending force is applied to the first member. On the other hand, the first member also may be bent in a second direction opposite to the first direction. In this case, when the neck has been warped toward a front side of the neck due to string tension, the first force may be applied to bend the neck toward the rear side by the adjusting mechanism so as to eliminate the warpage. On the other hand, when the neck has been warped toward the rear side, the second force may be applied to bend the neck toward the front side by the adjusting mechanism so as to eliminate the warpage in the rear side. As a result, warpage of the neck can be appropriately corrected or eliminated in response to the direction of warpage. 
     In another aspect of the present teachings, the adjusting mechanism may include a pull/push mechanism that may apply a pulling force and a pressing force to one end of the first member via the second member. In another aspect of the present teachings, one end of the first member may be fixedly connected to one end of the second member and the pull/push mechanism may be interposed between the other end of the first member and the other end of the second member. In another aspect of the present teachings, the pull/push mechanism may include a screw that is operable by an operator. 
     In another aspect of the present teachings, a control device may serve to control the bending direction of the first member in response to application of the respective first and second forces. 
     In another aspect of the present teachings, guitars are taught that may include the truing devices according to the aforementioned various aspects. 
     Additional objects, features and advantages of the present invention will be readily understood after reading the following detailed description together with the accompanying drawings and the claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG.  1 (A) is an exploded perspective view of a neck of a guitar and a first representative neck truing device; 
     FIG.  1 (B) is a cross-sectional view of the first representative neck truing device when it is disposed within the neck; 
     FIG. 2 is a side view showing the warped neck of the guitar and the first representative neck truing device in a curved configuration; 
     FIGS.  3 (A),  3 (B),  3 (C) and  3 (D) are schematic views illustrating the operation of the first representative neck truing device; 
     FIGS.  4 (A),  4 (B) and  4 (C) are a plan view, a longitudinal sectional view and a cross-sectional view of the first representative neck truing device; 
     FIG. 5 is an enlarged, cross-sectional plan view of the portion of FIG.  4 (A) indicated by numeral V; 
     FIG. 6 is a plan view of a forward portion of an alternative neck truing device; 
     FIG.  7 (A) is a side view of a second representative neck truing device; 
     FIGS.  7 (B) and  7 (C) are schematic views illustrating the operation of the second representative neck truing device; 
     FIGS.  8 (A) and  8 (B) are, respectively, a side view and a cross-sectional view of a known neck truing device; 
     FIGS.  8 (C)and  8 (D) are schematic views illustrating the operation of the known neck truing device; and 
     FIG.  8 (E) is a cross-sectional view of the known neck truing device embedded within a neck of a guitar. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In one embodiment of the present teachings, devices for correcting warpage of necks of stringed instruments may include a first bar-shaped member that extends along the longitudinal direction of the neck. A second bar-shaped member may extend along the first bar-shaped member. A first end portion of the second bar-shaped member may be fixed to a first end portion of the first bar-shaped member. A pull/push mechanism may be mounted on a second end portion of the first bar-shaped member and may apply a tensile force and a pressing force to a second end portion of the second bar-shaped member. A directing member may serve as a control device that directs the first bar-shaped member in one direction when a tensile force is applied to the second bar-shaped member by the pull/push mechanism and in an opposite direction when a pressing force is applied to the second bar-shaped member by the pull/push mechanism. 
     Therefore, when the tensile force is applied to the second bar-shaped member, the first bar-shaped member may bent or curved in one direction by the operation of the directing member. On the other hand, when a pressing force is applied to the second bar-shaped member, the first bar-shaped member may be curved in the other (opposite) direction by the operation of the directing member. As a result, not only the neck warpage due to the tension of the strings, but also warpage due to other factors, can be appropriately corrected or eliminated by the present truing devices. 
     In another embodiment of the present teachings, the pull/push mechanism may include a first actuation mechanism and a second actuation mechanism that is operationally connected with the first actuation mechanism so as to transmit an output of the first actuation mechanism to the second bar-shaped member. This arrangement may enable to a relatively small operational force to be converted into a relatively large output. Optionally, an actuation ratio of the first actuation mechanism may be different from an actuation ratio of the second actuation mechanism. 
     In another embodiment of the present teachings, the first actuation mechanism may include at least one component that also constitutes a component of the second actuation mechanism. For example, the first actuation mechanism and the second actuation mechanism may share a screw. 
     Preferably, the first actuation mechanism may include a first female thread and a first male thread. The first female thread may be formed in the second end portion of the first bar-shaped member. The first male thread may be formed on a screw and may threadably engage the first female thread. The second actuation mechanism may include a second male thread and a second female thread. The second male thread may be formed on the second end portion of the second bar-shaped member. The second female thread may be formed inside the screw and may threadably engage the second male screw. 
     In another embodiment of the present teachings, the first bar-shaped member may extend along a straight line and the second bar-shaped member may be curved when no tensile force or pressing force is applied to the second bar-shaped member. In another embodiment of the present teachings, the first bar-shaped member may include a longitudinal groove sized to accommodate the second bar-shaped member. In another embodiment of the present teachings, the directing member may include a plate that is disposed between a bottom of the groove of the first bar-shaped member and the second bar-shaped member. Preferably, a width of the groove of the first bar-shaped member and an outer diameter of the second bar-shaped member may be set to be substantially equal to each other, and the directing member may comprise side walls of the groove of the first bar-shaped member. 
     In another embodiment of the present teachings, the second bar-shaped member may be substantially coaxially disposed within the first bar-shaped member. In the alternative, the second bar-shaped member may be disposed in juxtaposed relationship with the first bar-shaped member and may extend substantially in parallel to the first bar-shaped member. 
     In another embodiment of the present teachings, guitars are taught that may include the truing devices according to the aforementioned various embodiments. 
     Each of the additional features and teachings disclosed above and below may be utilized separately or in conjunction with other features and teachings to provide improved neck truing devices for stringed instruments and guitars having such devices, and methods for designing and using such devices and guitars. Representative examples of the present invention, which examples utilize many of these additional features and teachings both separately and in conjunction, will now be described in detail with reference to the attached drawings. This detailed description is merely intended to teach a person of skill in the art further details for practicing preferred aspects of the present teachings and is not intended to limit the scope of the invention. Only the claims define the scope of the claimed invention. Therefore, combinations of features and steps disclosed in the following detail description may not be necessary to practice the invention in the broadest sense, and are instead taught merely to particularly describe representative examples of the invention. Moreover, various features of the representative examples and the dependent claims may be combined in ways that are not specifically enumerated in order to provide additional useful embodiments of the present teachings. 
     A first representative neck truing device (neck warpage correcting device)  10  will now be described with reference to FIGS.  1 (A) and  1 (B), FIG. 2, FIGS.  3 (A) to  3 ((D), FIGS.  4 (A) to  4 (C) and FIG.  5 . FIG.  1 (A) shows a guitar  1  that includes a neck  2 . The representative neck truing device  10  may be incorporated within the neck  2 . The parts of the guitar  1  other than the neck  2  are not shown for purpose of illustrating the essential aspects of the present teachings. In FIGS.  1 (A) and  1 (B), FIG. 2, FIGS.  3 (A) to  3 ((D), FIGS.  4 (A) to  4 (C) and FIG. 5, an X-axis, a Y-axis and a Z-axis are indicated by corresponding arrows. The X-axis, the Y-axis and the Z-axis respectively represent the widthwise (lateral) direction, the lengthwise (longitudinal) direction and the direction of thickness (or depth) of the neck  2 . In these drawings, the arrow indicating the Z-axis direction is oriented toward the front side of the neck  2 . 
     Referring to FIGS.  1 (A) and  1 (B), the neck  2  of the guitar  1  may include a flat finger-board  2   f  that covers the front surface of a neck body  2   m . An elongated groove  2   s  may defined in the center (in the widthwise direction) of the front surface of the neck body  2   m . The groove  2   s  preferably extends along the Y-direction (lengthwise direction) from the base end (lower end as viewed in FIG.  1 (A)) to a position near the tip or terminal end (upper end as viewed in FIG.  1 (B)) of the neck body  2   m . Preferably, the elongated groove  2   s  may have a substantially U-shaped cross-section. The representative neck truing device  10  may be accommodated and secured within the elongated groove  2   s . The neck  2  may be, e.g., made of wood. 
     The first representative neck truing device  10  may include a first bar-shaped member  12  whose length, width, and depth are substantially the same as those of the elongated groove  2   s  formed in the neck body  2   m . That is, the shape of the first bar-shaped member  12  preferably substantially corresponds to the configuration of the elongated groove  12 . The first bar-shaped member  12  may have a substantially U-shaped cross-sectional configuration and a longitudinal groove  12   m  may be defined within the first bar-shaped member  12 . As shown in FIG.  1 (B), the first bar-shaped member  12  may be accommodated within the elongated groove  2   s  such that the opening of the groove  12   m  is oriented downward (i.e., toward the bottom of the elongated groove  2   s ). Preferably, the first bar-shaped member  12  may be made of an aluminum alloy. 
     A plurality of thin longitudinal grooves (not shown) optionally may be defined along the outer surface of the first bar-shaped member  12 . These grooves may serve to increase the strength of adhesion when the first bar-shaped member  12  is adhered to the inner wall of the elongated groove  2   s  of the neck body  2   m.    
     As shown in FIGS.  4 (A),  4 (B) and  4 (C), a core-like second bar-shaped member  14  may be disposed or accommodated within the groove  12   m  of the first bar-shaped member  12 . A flange-shaped stopper  14   s  may be formed or disposed at the forward end (left end as viewed in FIGS.  4 (A) and  4 (B)) of the second bar-shaped member  14 . The stopper  14   s  may be disposed external to the forward end (left end as viewed in FIGS.  4 (A) and  4 (B)) of the first bar-shaped member  12 . The second bar-shaped member  14  may include a fixing portion  13  that is disposed near the stopper  14   s . The first bar-shaped member  12  and the second bar-shaped member  14  may be adhered (e.g., caulked) at the fixing portion  13  from the outside of the first bar-shaped member  12 . In this case, the forward end portion of the second bar-shaped member  14  will be affixed to the forward end portion of the first bar-shaped member  12 . 
     The stopper  14   s  may primarily function to maintain the relative position of the forward end portion of the first bar-shaped member  12  with respect the forward end portion of the second bar-shaped member  14 , in particular, when a tensile force is applied to the forward end portion of the second bar-shaped member  14  toward the right direction as viewed in FIGS.  4 (A) and  4 (B). In addition, the fixing portion  13  and the caulked portion of the first bar-shaped member  12  may function to maintain the relative position of the forward end portion of the first bar-shaped member  12  with respect the forward end portion of the second bar-shaped member  14 , thereby preventing the first bar-shaped member  12  from moving relative to the second bar-shaped member  14 , even when a pressing force is applied to the forward end portion of the second bar-shaped member  14  in the left direction as viewed in FIGS.  4 (A) and  4 (B). 
     The second bar-shaped member  14  preferably may be formed as a cylindrical tube and may have an outer diameter that is substantially equal to the width of the elongated groove  12   m  of the first bar-shaped member  12 . Further, a plurality of pieces of resin tape  14   j  may be wound around the outer peripheral surface of the second bar-shaped member  14  at a plurality of positions along the longitudinal direction of the second bar-shaped member  14 . The resin tapes  14   j  may serve to prevent the generation of vibrations (or dampen vibrations) between the first bar-shaped member  12  and the second bar-shaped member  14 . The second bar-shaped member  14  may be preferably made of iron, steel or any other suitable material. Preferably, the rigidity of the second bar-shaped member  14  is greater than the rigidity of the first bar-shaped member  12 . 
     Referring to FIG. 5, a male thread  14   t  may be defined on the outer surface of the base end portion (right end portion as viewed in FIGS.  4 (A) and  4 (B)) of the second bar-shaped member  14 . The male screw  14   t  may threadably engage a female thread  25   w  defined on a screw  25 , which will be further described below. 
     Referring to FIG.  4 (B), a plate  15  may be disposed or interleaved between the second bar-shaped member  14  and the bottom surface  12   b  of the groove  12   m  of the first bar-shaped member  12 . The plate  15  may be attached or affixed to the bottom surface  12   b  of the first bar-shaped member  12  and may serve as a reference point when the first bar-shaped member  12  bows or curves in the upward direction (as viewed in FIG.  4 (B)), which will be further explained below. The position of the plate  15  preferably may be appropriately adjusted along the longitudinal direction of the first bar-shaped member  12 . In this case, the plate  15  may constitute a directing member for controlling the bowing or bending direction of the first bar-shaped member  12 . 
     Referring to FIGS.  4 (A) and  4 (B), a block-shaped fixing member  20  may be fixedly attached to the base end portion (right end portion as viewed in FIGS.  4 (A) and  4 (B)) of the first bar-shaped member  12  by an adhesive or by any other suitable means. As shown in FIG. 5, a small-diameter through-hole  21  and a large-diameter through-hole  22  may be coaxially defined within the fixing member  20 . Further, the base end portion of the second bar-shaped member  14  may be inserted into the small-diameter through-hole  21 . A female thread  22   w  is preferably defined within the large-diameter through-hole  22  of the fixing member  20 . The screw  25  may include a male thread  25   t  that threadably engages the female thread  22   w  from a direction opposite to the second bar-shaped member  14 . Thus, the fixing member  20  may essentially serve as a nut for receiving the screw  25 . 
     The screw  25  may include a head portion  25   h  and a shaft portion  25   j . The male thread  25   t  may be defined on the outer peripheral surface of the shaft portion  25   j . The female thread  25   w  may be defined on the peripheral wall of a deep axial hole  25   e  that is defined within the shaft portion  25   j . The male thread  14   t  of the second bar-shaped member  14  may threadably engage the female thread  25   w  of the screw  25 . 
     Preferably, the male thread  25   t  and the female thread  22   w , as well as the male thread  14   t  and the female thread  25   w , may be formed as right-handed or clockwise threads. In addition, the pitch of the male thread  25   t  and the female thread  22   w  is preferably different from the pitch of the male thread  14   t  and the female thread  25   w . For example, the pitch of the male thread  25   t  and the female thread  22   w  may be set at 0.5 mm, and the pitch of the male thread  14   t  and the female thread  25   w  may be set at 0.8 mm. 
     According to this arrangement, when the male thread  25   t  of the screw  25  rotates in the tightening direction (clockwise direction) with respect to the female thread  22   w  of the fixing member  20 , the screw  25  may move deeper into the fixing member  20  (i.e., move to the left as viewed in FIG.  5 ). At the same time, the male thread  14   t  of the second bar-shaped member  14  and the female thread  25   w  of the screw  25  also may be tightened. In this case, the base end portion of the second bar-shaped member  14  may be pulled by the screw  25  so as to move rightward as viewed in FIG.  5 . However, as noted above, the pitch (e.g., 0.5 mm) of the male thread  22   w  is preferably smaller than the pitch (e.g., 0.8 mm) of the male thread  14   t  and the female thread  25   w . Therefore, the base end portion of the second bar-shaped member  14 . 
     On the other hand, when the male thread  25   t  of the screw  25  rotates in the loosening direction (counter-clockwise direction) with respect to the female thread  22   w  of the fixing member  20 , the screw  25  retreats or withdraws from the fixing member  20  (i.e., moves rightward as viewed in FIG.  5 ). At the same time, the male thread  14   t  of the second bar-shaped member  14  and the female thread  25   w  of the screw  25  may be loosened, so that the base end portion of the second bar-shaped member  14  may be axially pressed by the screw  25  so as to moved leftward as viewed in FIG.  5 . Therefore, the base end portion of the second bar-shaped member  14  may move leftward by a distance that corresponds to the difference between the pitch of the male thread  25   t  and the female thread  22   w  and the pitch of the male thread  14   t  and the female thread  25   t . As a result, an axial pressing force will be applied to the base end portion of the second bar-shaped member  14 . 
     The fixing member  20 , the screw  25 , the male thread  25   t  and the female thread  22   w  may constitute a first actuation mechanism according to the present teachings. Further, the screw  25 , the male thread  14   t  and the female thread  25   w  may constitute a second actuation mechanism according to the present teachings. In addition, a screw mechanism that includes the male thread  25   t , the female thread  22   w , the male thread  14   t , the female thread  25   w , the fixing member  20  and the screw  25  may constitute a pulling/pressurizing mechanism according to the present teachings. Moreover, the screw  25  may serve as a component of the first actuation mechanism and also may serve as a component of the second actuation mechanism. 
     Preferably, the fixing member  20  may be made of brass and the screw  25  may be made of iron. In the alternative, the fixing member  20  may be formed of a die-cast zinc alloy in order to reduce manufacturing costs. 
     A representative method for operating the first representative neck truing device  10  will now be described. As shown in FIGS.  1 (A) and  1 (B), the neck truing device  10  may be positioned within the elongated groove  2   s  formed in the neck body  2   m  of the neck  2  of the guitar  1  such that the forward end (upper end as viewed in FIG.  1 (A)) of the first bar-shaped member  12  substantially contacts the forward end of the elongated groove  2   s . In addition, adhesive (not shown) may be applied to the outer surface of the first bar-shaped member  12 . Then, the first bar-shaped member  12  may be forced (press-fitted) into the elongated groove  2   s  such that the opening of the groove  12   m  opposes the innermost side (bottom side) of the elongated groove  2   s . After the neck truing device  10  has thus been accommodated within the elongated groove  2   s  of the neck body  2   m , the finger-board  2   f  may be adhered (e.g., glued) or fixed to the front surface of the neck body  2   m . As a result, the neck truing device  10  will be embedded and enclosed within the neck  2  to thereby integrate the first bar-shaped member  12  with the neck  2 . 
     As shown in FIGS.  3 (A) and  3 (C), which show the neck truing device  10  embedded within the neck  2 , the first bar-shaped member  12  may extend along a straight line. In this state, no substantial tensile force or pressing force will be applied to the second bar-shaped member  14 . Further, the second bar-shaped member  14  will contact the plate  15  and curve or bow slightly downwards. 
     When the neck  2  has been curved or warped toward the front side of the guitar  1  due to the tension of the strings  4 , which warpage is indicated by chain lines T 1  in FIG.  2  and FIG.  3 (A), the operator may rotate screw  25  in the clockwise (tightening) direction. In this case, a tensile force will be applied to the second bar-shaped member  14 . As the base end portion of the second bar-shaped member  14  is pulled by the screw  25 , the second bar-shaped member  14  will force the first bar-shaped member  12  to curve upward under the directional control of the plate  15 , as shown in FIG.  3 (B)-As a result, the first bar-shaped member  12  will curve upwards. That is, the first bar-shaped member  12  may be curved or bowed within the neck  2  in a direction that is opposite to the warpage of the neck  2  (indicated by chain lines T 1 ). As a result, the warpage of the neck  2  can be corrected or eliminated and the neck  2  can be straightened. The degree of curvature of the first bar-shaped member  12  can be controlled by adjusting the amount of rotation (i.e., tightening and loosening) of the screw  25 . 
     On the other hand, when the neck  2  has been warped toward the rear side of the guitar  1 , which is indicated by chain lines T 2  in FIG.  3 (C), even the operator may rotate the screw  25  in a counter-clockwise (loosening) direction to thereby push or press the base end portion of the second bar-shaped member  14  in the axial direction. As the base end portion of the second bar-shaped member  14  is pushed in the axial direction, the second bar-shaped member  14  may deform to increase the curvature along and between the side walls of the groove  12   m  of the first bar-shaped member  12 , as shown in FIG.  3 (D). The forward end portion of the second bar-shaped member  14  may then press the forward end portion of the first bar-shaped member  12  in the axial direction. Because the second bar-shaped member  14  is curved at this time, the forward end portion of the second bar-shaped member  14  will apply a pressing force F to the forward end portion of the first bar-shaped member  12   w  in a direction obliquely upwards. The pressing force F may have a component Fu directed in the Z-direction, which component Fu will push up the forward end portion of the first bar-shaped member  12 . As a result, the first bar-shaped member  12  may be curved further downwards. 
     Thus, according to this representative method, the first bar-shaped member  12  may be curved within the neck  2  in the direction opposite to the warpage of the neck  2  (indicated by chain lines T 2  in FIG.  3 (C)). Consequently, warpage of the neck  2  can be corrected or eliminated and the neck  2  can be trued or straightened. In the example shown in FIGS.  3 (C) and  3 (D), the side walls of the groove  12   m  of the first bar-shaped member  12  may serve to determine the curving direction of the first bar-shaped member  12 . 
     As described above, the first representative neck truing device  10  includes a pulling/pressurizing mechanism (e.g., the male thread  25   t , the female thread  22   w , the male thread  14   t  and the female thread  25   w ) that is disposed at the base end of the first bar-shaped member  12 . Therefore, it is possible to apply a tensile force and a pressing force to the forward end portion of the second bar-shaped member  14 . When the tensile force is applied to the second bar-shaped member  14 , the first bar-shaped member  12  may curve or bow upwards under the directional control of the plate  15 , as shown in FIG.  3 (B). In this case, the plate  15  serves as a directing member or a control device for controlling the curving or bowing direction of the first bar-shaped member  12  when the tensile force is applied to the second bar-shaped member  14 . 
     When the pressing force is applied to the second bar-shaped member  14 , the first bar-shaped member  12  may curve or bow downwards along the side walls of the groove  12   m  of the first bar-shaped member  12 , as shown in FIG.  3 (D). In this case, the plate  15  serves as a directing member or a control device for controlling the curving direction of the first bar-shaped member  12  when the pressing force is applied to the second bar-shaped member  14 . 
     Thus, not only the warpage of the neck  2  toward the front side due to the tension of the strings  4 , but also the warpage of the neck  2  toward the rear side, can be appropriately corrected or eliminated. 
     Because means for pulling the second bar-shaped member  12  and means for pressurizing the second bar-shaped member  14  may be integrated into a single unit, i.e. The pulling/pressurizing mechanism, the neck truing device  10  may be relatively compact in size. Further, if the pitch of the male thread  25   t  and the female thread  22   w  is smaller than the pitch of the male thread  14   t  and the female thread  25   w , the difference between these pitches may produce a force that pulls and presses the other end portion of the second bar-shaped member  14 . In this case, the force required by the operator to rotate the screw  25  may be reduced. 
     Further, by disposing or accommodating the second bar-shaped member  14  within the groove  12   m  of the first bar-shaped member  12 , the neck truing device  10  can be made more compact in size. 
     As described above in the first representative embodiment, the forward portion of the first bar-shaped member  12  and the forward portion of the second bar-shaped member  14  are fixed to each other by caulking the first bar-shaped member  12  at the fixing portion  13  of the second bar-shaped member  14 . However, the forward portions of the first and second bar-shaped members  12  and  14  also may be fixed to each other, e.g., by a T-shaped fixing member  26 , as shown in FIG. 6, which is a modification of the embodiment shown in FIGS. 1-5. 
     In the alternative embodiment shown in FIG. 6, the fixing member  26  may be made of a plate that has a predetermined thickness. In addition, the fixing member  26  may include a lengthwise portion  26   b  that extends substantially perpendicular to a crosswise portion  26   a . First recesses  27  may be defined in the upper end surfaces of the first bar-shaped member  12  on the opening side of the U-shape of the first-bar-shaped member  12 . The first recesses  27  may serve to closely receive the respective ends of the crosswise portion  26   a  Also, a second recess  28  may be defined in the upper surface of the second bar-shaped member  14  and may serve to closely receive the central portion of the crosswise portion  26   a  and the lengthwise portion  26   b  of the fixing member  26 . 
     In this alternative embodiment, the first bar-shaped member  12  may be caulked against the second bar-shaped member  14  from both lateral sides at a position opposing to the lengthwise portion  26   b  of the fixing member  26 , as indicated by arrows shown in FIG.  6 . Therefore, the first bar-shaped member  12 , the second bar-shaped member  14  and the fixing member  26  may be fixed in position relative to each other. In addition, the fixing member  26  may be welded to the second bar-shaped member  14  at the forward and rearward ends of the second recess  28 , e.g., by argon arc welding, as indicated by weld line W 1  and W 2  shown in FIG.  6 . As a result, the forward portions of the first and second bar-shaped members  12  and  14  may be reliably fixed in position relative to each other during the curving or bowing operation of the neck truing device  10 . 
     A second representative neck truing device  30  will now be described with reference to FIGS.  7 (A) to  7 (C). As described above, according to the first representative neck truing device  10 , the first bar-shaped member  12  has a substantially U-shaped cross-sectional configuration so as to accommodate the second bar-shaped member  14 . In the alternative, the second representative neck truing device  30  may include a first bar-shaped member  32  and a second bar-shaped member  34  that each has a substantially cylindrical configuration. Due to this configuration, the first bar-shaped member  32  may be easily manufactured. In addition, the forward end portions of the first and second bar-shaped members  32  and  34  can be connected more easily. Thus, in the second representative neck truing device  30 , the second bar-shaped member  34  may be disposed in a juxtaposed relationship with respect to the first bar-shaped member  32 . The forward end portions of the first and second bar-shaped members  32  and  34  may be connected, e.g., by welding, as indicated by weld line W shown in FIG.  7 (A). 
     The second representative neck truing device  30  also may include a screw and a fixing member. The construction of the screw and fixing member may be generally the same as the screw  25  and the fixing member  20  of the first representative neck truing device  30 . Thus, in FIGS.  7 (A) to  7 (C), like members are given the same reference numerals as the first representative embodiment and an explanation of these like members is not necessary. 
     Preferably, the first and second bar-shaped members  32  and  34  of the second representative neck truing device  30  may be made of iron or a similar rigid material. In this case, the outer diameter of the second bar-shaped member  34  may be slightly larger than the outer diameter of the first bar-shaped member  32 . As a result, the first bar-shaped member  32  may easily deform (i.e., curve or bow) with respect to the second bar-shaped member  34 . 
     A short cylinder  32   f  may be attached to the outer periphery of the first bar-shaped member  32  at a predetermined position. A short cylinder  34   e  may be attached to the outer periphery of the second bar-shaped member  34  at a position opposing or adjacent to the short cylinder  32   f . The short cylinder  32   f  of the first bar-shaped member  32  preferably contacts the short cylinder  34   e  of the second bar-shaped member  34  when the second neck truing device  30  is assembled. 
     Optionally, a plurality of pieces of resin tape (not shown) may be wound around the respective peripheries of the first and second bar-shaped members  32  and  34 . The resin tapes wound around the first bar-shaped members  32  may contact the corresponding resin tapes wound around the second bar-shaped members  34 . In this case, vibrations may be reliably prevented from occurring (or dampened) between the first and second bar-shaped members  32  and  34 . 
     When the operator rotates the screw  25  in the counter-clockwise direction, a tensile force may be applied to the second bar-shaped member  34 . Therefore, the forward end portion of the first bar-shaped member  32  may receive an upward tensile force as shown in FIG.  7 (B). Consequently, the first bar-shaped member  32  will curve or bow downwards taking the position of the short cylinders  32   f  and  34   e  as a reference point. 
     Conversely, when the operator rotates the screw  25  in a clockwise direction, a pressing force may be applied to the base end portion of the second bar-shaped member  34 . In this case, the forward end portion of the first bar-shaped member  32  will receive a downward pressing force as shown in FIG.  7 (C). As a result, the first bar-shaped member  32  will curve or bow upwards taking the position of the short cylinders  32   f  and  34   e  as a reference point. Therefore, the short cylinders  32   f  and  34   e  also may constitute a directing mechanism (or control device) for determining the curving or bowing direction of the first bar-shaped member  32  of the second representative neck truing device  30 . 
     Thus, in the second representative device  30  as well, warpage of the neck  2  in one direction due to the tension of the strings  4  and the warpage of the neck  2  in the opposite direction may be corrected or eliminated by deforming (curving) of the first bar-shaped member  12  in the appropriate direction. This correction may be performed by simply rotating the screw  25 . 
     The first and second representative embodiments may also be modified in additional ways. For example, the first and second actuation mechanisms of the pulling/pressurizing mechanism in the first representative neck truing devices  10  or the second representative neck truing device  30  are constituted by screw mechanisms. However, in the alternative, the first and second actuation mechanisms may be constituted by another mechanism, such as a lever mechanism. Further, although the first and second representative neck truing devices  10  and  30  were described as being suitable for mounting the neck  2  of the guitar  1 , naturally, the present neck truing devices may also be suitable utilized with a variety of other stringed instruments, such as violins and cellos.