Guitar with neck truss rod supporting construction

A guitar comprising a neck truss rod supporting construction capable of firmly coupling its elements, such as a fret board, a neck, a guitar body and a front board of the guitar body, with one another. The neck truss rod supporting construction includes a truss rod supporting member, an extension member providing a wide bonding area and a coupling member having a cross-sectional shape of a trapezoid rotated 90.degree. and engaged in a block of the guitar body in a dovetail manner. The extension member has upper walls extending transversely and defining recesses among them. The front board of guitar body also has an opening engaged with the upper walls of extension member in a fit manner. At upper surfaces of the truss rod supporting member and the extension member, a plurality of longitudinal shallow slots are formed to provide positive bonding surfaces. The truss rod support construction does not move relatively to the guitar body and the neck, so that any relative movement between the truss rod and the neck does not occur even when a variation in the moisture content of the wood material of the neck occurs. Moreover, there is no any phenomenons such as cracking or bowing of the neck.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a guitar, and more particularly to a 
guitar with a neck truss rod supporting construction. 
2. Description of the Prior Art 
In guitars of the type including a body having a resonating sound chamber 
and a neck both of which are made from wood, the neck is subjected to 
warpage from the factors such as the tension of tightened strings, the 
external heat and the external force. Where the neck is bowed, a fret 
board can not align horizontally with the front board of the guitar body. 
This may cause a deterioration in acoustic quality. To compensate for the 
factors, in particular, the string tension, an adjustable truss rod has 
been conventionally inserted into the neck to straighten the bowed neck, 
thereby enabling the fret board to align horizontally with the front board 
of the guitar body. The truss rod is supported to the neck by means of a 
truss rod supporting member fitted to a block fixed to the guitar body. 
In cases of guitars of the type including an elongate neck, the 
constructional firmness thereof is insufficient because of a small bonding 
area between the fret board and the front board of the guitar body. 
Furthermore, the bonding between the fret board and the front board of the 
guitar body often becomes poor. Due to the provision of the truss rod, 
there is also a problem as to the constructional firmness. That is, since 
the truss rod is supported to the neck only by means of the supporting 
member fitted to the block fixed to the guitar body, a relative movement 
between the truss rod and the neck tends to occur due to a variation in 
the moisture content of the wood material of the neck. Moreover, 
phenomenons such as cracking or bowing of the neck may occur. 
SUMMARY OF THE INVENTION 
Therefore, an object of the invention is to provide a guitar with a neck 
truss rod supporting construction capable of firmly coupling its elements, 
such as a fret board, a neck, a guitar body and a front board of the 
guitar body, with one another, thereby achieving an improvement in 
constructional firmness. 
In accordance with the present invention, this object can be accomplished 
by providing a guitar comprising a guitar body having a front board and a 
side board, a neck having a slot receiving a truss rod and a neck truss 
rod supporting construction, and a fret board attached to the neck, 
characterized in that said neck truss rod supporting construction 
comprises: an elongate, truss rod supporting member adapted to support 
said truss rod and provided at its rear end with a heel extending 
downwardly and at its upper surface with a plurality of longitudinal 
shallow slots for forming a bonding surface; a coupling member formed at 
the rear end of the truss rod supporting member behind said heel and 
integrally connected to the heel, said coupling member extending 
downwardly from the truss rod supporting member and has a cross-sectional 
shape of a trapezoid rotated 90.degree.; an extension member integrally 
formed with the truss rod supporting member behind the coupling member and 
provided with a plurality of upper walls extending transversely and 
defining recesses among them, said extension member also having a 
plurality of longitudinal shallow slots for forming a bonding surface at 
an upper surface defined by all the upper walls; a plurality of throughout 
holes formed in at least one of the upper walls of the extension member 
and each adapted to receive a nail or screw; reinforcing members mounted 
beneath at least one of the upper walls at both sides of the extension 
member and adapted to reinforce the upper wall; a block fixedly mounted to 
the side board in the guitar body and provided with a first groove having 
the same cross-sectional shape as that of the coupling member and 
receiving the coupling member and a second groove receiving the extension 
member; and an opening formed at the front board of the guitar body and 
having the same shape as that of the upper surface of the extension member 
.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIG. 1, there is illustrated a neck truss rod supporting 
construction of a guitar in accordance with the present invention. 
As shown in FIG. 1, the neck truss rod supporting construction which is 
designated by the reference numeral 1 comprises an elongate, truss rod 
supporting member 2 adapted to support a truss rod (not shown) and 
provided with an upper wall 2a and a pair of opposite side walls 2b and 
2b' (FIG. 2A), and a heel 4 provided at the rear end (namely, the right 
end in FIG. 1) of the truss rod supporting member 2 and extending 
downwardly therefrom. The truss rod supporting member 2 also has a 
plurality of spaced ribs 3 arranged along the length of the truss rod 
supporting member 2 and extending downwardly from the bottom surface of 
the upper wall 2a, as shown in FIGS. 2B and 4. At the upper surface of the 
upper wall 2a, a bonding surface 5 is provided, which is formed by a 
plurality of longitudinal shallow slots 10 formed on the upper surface of 
the upper wall 2a, as shown in FIGS. 2A and 2B. Behind the heel 4, a 
coupling member 6 is formed at the rear end of the truss rod supporting 
member 2 and integrally connected to the heel 4. The coupling member 6 
extends downwardly from the truss rod supporting member 2 and has a 
cross-sectional shape of a trapezoid rotated 90.degree., as shown in FIG. 
2C. 
Behind the coupling member 6, an extension member 7 is integrally formed 
with the truss rod supporting member 2. The extension member 7 has a 
plurality of upper walls 7', 7" and 7"' (three in case of the illustrated 
embodiment) extending transversely to provide a wide bonding surface. 
Adjacent upper walls of the extension member 7 define recesses to provide 
a mechanical coupling between the extension member 7 and a guitar body. In 
similar to the upper wall 2a of the truss rod supporting member 2, a 
plurality of longitudinal shallow slots 10' are formed at the upper 
surface of the extension member 7, so as to provide a bonding surface 9. 
Each upper wall 7' (or 7", or 7"') has a plurality of throughout holes 8 
(or 8', or 8") which permit a coupling between a fret board and a front 
board of the guitar body using nails or screws. In order to reinforce the 
upper walls of the extension member 7, reinforcing members may be mounted 
beneath the upper walls at both sides of the extension member 7. In the 
illustrated embodiment, a pair of reinforcing members 11 and 11' are 
provided beneath the upper wall 7"'. 
A recess 5' is also provided between the bonding surface 5 of the truss rod 
supporting member 2 and the bonding surface 9 of the extension member 7. 
In the drawings, the reference numeral 12 designates the fret board, 13 the 
neck, 13' a slot formed in the neck 13 to receive the neck truss rod 
supporting construction 1, 15 a guitar body in which a resonating sound 
chamber is formed, 14 the front board of the guitar body, and 16 a side 
board of the guitar body 15. 
In the guitar body 15, a block 17 is fixedly mounted to the side board 16 
of the guitar body 15 and adapted to firmly support the neck truss rod 
supporting member 2. The block 17 has a first groove 18 having the same 
cross-sectional shape as that of the coupling member 6 and receiving the 
coupling member 6 and a second groove 19 receiving the extension member 7. 
On the other hand, the front board 14 of the guitar body 15 provided with 
an opening having the same shape as that of the upper surface of the 
extension member 7. 
This neck truss rod supporting construction 1 with the above-mentioned 
structure functions to support an adjustable truss rod which is adapted 
for straightening the neck 13, when the fret board 12 does not align 
horizontally with the front board 14 of the guitar body 15, due to a 
bowing of the neck caused by the tension of tightened strings, the 
external heat or the external force, thereby causing the acoustic quality 
to be deteriorated. 
Now, assembling of the neck truss rod supporting construction with the neck 
and the guitar body will be described in detail, in conjunction with FIG. 
3. 
Upon assembling the neck truss rod supporting construction 1 with the 
guitar body 15 to which the neck 13 has been previously bonded, the neck 
truss rod supporting construction 1 is first inserted in the neck 13. At 
this time, the truss rod supporting member 2 is received in the slot 13' 
of the neck 13 while the heel 4 is fitted to a vertical groove formed at 
the neck 13 behind the rear end of the slot 13'. Also, the coupling member 
6 is fitted to the first groove 18 of the block 17 while the extension 
member 7 is received in the second groove 19 of the block 17. On the other 
hand, the upper walls 7', 7" and 7"' of the extension member 7 is engaged 
in the opening 20 of the front board 14. 
In order to provide an adhesion between the neck truss rod supporting 
construction 1 and both of the neck 13 and the guitar body 15, surface 
portions of the neck truss rod supporting construction 1 to come into 
contact with both of the neck 13 and the guitar body 15 have been applied 
with an adhesive, prior to the assembling. 
Thereafter, an adhesive is applied to the upper surface of the neck 13, the 
bonding surface 5 of the truss rod supporting member 2 and the bonding 
surface 9 of the extension member 7. The fret board 12 is then attached to 
the bonding surface 5 of the truss rod supporting member 2 and the bonding 
surface 9 of the extension member 7. At this time, the adhesive is 
penetrated into the slots 10 and 10' and the throughout holes 8, 8' and 
8". 
Since the adhesive is penetrated into the slots 10 and 10' and the 
throughout holes 8, 8' and 8" as mentioned above and the extension member 
7 provides a wide bonding area, the fret board 12 can be more firmly fixed 
to all of the neck truss rod supporting member 2, the neck 13 and the 
guitar body 15. In particular, since the coupling member 6 is engaged in 
the first groove 18 of the block 17 in a dovetail manner and the upper 
walls 7', 7" and 7"' of the extension member 7 are also engaged in the 
opening 20 of the front board 14 in a fit manner, the truss rod support 
construction 1 and thus the fret board do not move relatively to the 
guitar body 15 and the neck 13, so that any relative movement between the 
truss rod and the neck does not occur even when a variation in the 
moisture content of the wood material of the neck occurs. If desired, 
nails or screws may be fitted in throughout holes 8, 8' and 8" formed at 
the extension member 7, to provide more improved constructional firmness. 
As apparent from the above description, the present invention provides a 
guitar with a neck truss rod supporting construction capable of firmly 
coupling its elements, such as a fret board, a neck, a guitar body and a 
front board of the guitar body, with one another, by the provisions of an 
extension member providing a wide bonding area, a coupling member engaged 
in a block of the guitar body in a dovetail manner and upper walls of the 
extension member engaged in an opening of the front board in a fit manner. 
The neck truss rod supporting construction achieves an improvement in 
constructional firmness. The truss rod support construction and thus the 
fret board do not move relatively to the guitar body and the neck, so that 
any relative movement between the truss rod and the neck does not occur 
even when a variation in the moisture content of the wood material of the 
neck occurs. Moreover, there is no any phenomenons such as cracking or 
bowing of the neck. As a result, an improvement in acoustic quality can be 
obtained. 
Although the preferred embodiments of the invention have been disclosed for 
illustrative purpose, those skilled in the art will appreciate that 
various modifications, additions and substitutions are possible, without 
departing from the scope and spirit of the invention as disclosed in the 
accompanying claims.