DE29503407U1 - Truss rod for stringed instruments - Google Patents

Description

String instruments

^ The invention relates to a truss rod for stringed instruments, in particular for guitars with steel strings, whereby the truss rod can be embedded in the instrument neck below the fingerboard and serves to compensate for the bending forces and moments exerted on the instrument neck by the tensioned strings, according to the preamble of claim 1.

Such truss rods are mainly used on electric guitars (electric guitars) because they are equipped with steel strings due to the magnetic pickups. Due to the relatively high tensile forces of the tensioned steel strings, bending forces and moments are exerted on the instrument neck. The resulting possible detuning of the instrument (due to a bend in the neck) is undesirable, even to a small extent, and must be corrected. The invention is based on the task of creating a truss rod of the type mentioned above with which a convenient and rapid correction of the pitch is possible, i.e. before or during a musical performance. In particular, the invention should make it possible - this concerns a sub-task - to use a wrench to grip an easily accessible adjustment element and to be able to effect the correction with a small angle of rotation, whereby the transmission of torsional forces via a long stretch rod should be avoided.

According to the invention, the stated object is achieved by the features specified in the characterizing part of claim 1, namely in that the truss rod is a double rod, the individual rods of which are firmly connected to one another at a first end and are in engagement with one another at their second end via a screw coupling with an adjustable screw element,

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that in order to achieve a compensating curvature of the truss rod, the length of one, first individual rod can be changed relative to the other individual rod by turning the screw element.

Advantageous further developments of the subject matter of the invention are specified in claims 2 to 8. The advantages that can be achieved with the invention are primarily that a corrective bending of the truss rod can be achieved by means of the screw coupling on one end of the truss rod that is accessible from the outside, without the screw movement having to be transmitted over the length of the rod to its other end, i.e. individual rod torsion and thus unstable correction due to springback is avoided. According to claim 2, a corrective bulge transverse to the longitudinal direction of the rod is possible in both directions. A preferred embodiment is specified in claim 3, the special feature of which is the double threaded nut. This is expediently provided on its front side that is accessible from the outside with an internal polygon for the attachment of a rotary wrench (claim 4-). A hexagon socket and an associated Allen key are preferably provided. The advantageous measures according to claim 5 ensure that when the double threaded nut is rotated clockwise or counterclockwise, the first individual rod can be shortened or lengthened by a change in length increased by adding the two thread pitches.

In the following, an embodiment of the invention is described with reference to the drawing and its mode of operation as well as further features and advantages of the invention are explained.

In the drawing shows:
35.

Fig. 1 shows a truss rod according to the invention in a shortened representation and in a partial section I - I of its screw coupling according to section plane I - I in Fig. 2;

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the front view X of the truss rod according to Fig. 1; Fig^^ the truss rod according to Fig. 1 and 2 in overall view and

reduced in a straight zero position (a) and in 5, two curved in opposite directions

Positions (b or c) and

- Fig^ 4; in schematic and simplified representation a

&Egr; guitar in cutout with embedded truss rod according to the invention.
10

In the case of the E-guitar according to Fig. 4-, only the body e 1, the neck e 2 and the head e 3 with the tuning pegs e 4- and the truss rod 1 inserted and embedded in the neck e 2 below the fingerboard e 5 are shown in dashed lines. The truss rod 1 serves to compensate for the bending forces and moments exerted by the tensioned strings (not shown) on the instrument neck e 2.

According to Fig. 1 to 3, the neck rod 1 is according to the invention a double rod, the individual rods 1a, 1b of which are firmly connected to one another at a first end ¹¹ (brazed seam 2) and engage with one another at their second end 1'' via a screw coupling 3 with an adjustable screw element 4 in such a way that, in order to achieve a compensating bulge (b or c according to Fig. 3), the length £i of one, first individual rod 1a can be changed relative to the other (second) individual rod 1b by rotating the screw element M- . The length of the first individual rod 1a in its zero position a (Fig. 3) is designated by <ti. The screw coupling 3 is now designed in particular in such a way that the first individual rod 1a can be shortened relative to the second individual rod 1b (see Fig. 3 _; bulge b in direction f^, so that £2<11) as well as extended (see Fig. 3> bulge c in direction f, so that i3>£i) In this way, in relation to the straight zero position a

35- of the neck rod 1 allows a bulge b or c transverse to the longitudinal direction of the rod 1.0 in both directions f^ or f.

According to Fig. 1 and 2, the second single rod 1b is provided at its second end 1'' with a fixed threaded sleeve 5 with internal

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thread L1. The fixed connection can be a brazed joint seam 6 according to (2), the seams 2, 6 can, however, be formed by weld seams depending on the magnitude of the forces to be transmitted. The screw element 4 in the form of a double threaded nut (DGM) with an external thread L2 is screwed into the threaded sleeve 5, the latter is abbreviated to DGM 4 below. The DGM 4 has an internal thread R1, which is opposite to its external thread L2 and into which the second end 1'' of the first individual rod 1a is screwed with an external thread or thread R2, so that when the DGM 4 is rotated in a first direction of rotation d^ (see Fig. 3 and 4) the first individual rod 1a can be reduced in length -£i to a length ^2 and when the DGM 4 is rotated in the opposite direction of rotation d the first individual rod can be increased in length, e.g. to the length -C 3.

The DGM 4 is provided on its front side 4a accessible from the outside with a polygon socket, in particular a hexagon socket 4b for attaching a wrench 7 (Fig. 4), in particular an Allen key. A left-hand thread L1, L2 between the threaded sleeve 5 and DGM 4 and a right-hand thread R1, R2 between DGM 4 and the second end 1'' of the first individual rod 1a are particularly favorable for convenient and quick handling, as provided, so that when the DGM 4 is rotated clockwise (dl.) or counterclockwise (cL), the first individual rod 1a can be shortened or lengthened by a change in length (Cl - �Idigr;2) or ({3 - i1) increased by adding the two thread pitches. The first individual rod 1a is preferably a round rod and the second individual rod 1b is a flat rectangular rod, one broad side 8 of which faces the first individual rod 1a. The first individual rod 1a is, as shown in Fig. 1, slimmer in the area of its thread R2 because its thread diameter must be adapted to the internal thread diameter of the DGM 4; the remaining rod length, with which the compensation forces are applied, remains unweakened. An advantageous thread combination is as follows: an M 8 - left-hand thread between threaded sleeve 5 and DGM 4 and an M 5 - right-hand thread between DGM 4 and the first

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Single rod 1a (without wishing to limit the invention thereto).

Fig. 4 shows that the Allen key 7 can be attached to the hexagon socket 4-b of the DGM 4- due to an elongated recess 9 in the body e 1, which leaves one end 1' ¹ of the truss rod 1 free.

8 Claims
^- Fig.

Claims (1)

- 6 - -my reference 95/0220 G Protection claims 1. Truss rod for string instruments, especially guitars with steel strings, whereby the truss rod can be embedded in the instrument neck below the fingerboard and serves to compensate for the bending forces and moments exerted by the tensioned strings on the instrument neck,
characterized in that the neck rod is a double rod (1), the individual rods (id/ib) of which are firmly connected to one another at a first end ( ¹¹ ) and engage with one another at their second end (1") via a screw coupling (3) with an adjustable screw element (4-) in such a way that, in order to achieve a compensating curvature (bjC) of the neck rod ( i ), the length of one first individual rod (1&) can be changed relative to the other individual rod (1b) by rotating the screw element ( 4- ). 2. Tie rod according to claim 1, characterized in that the first individual rod (11) can be both shortened and lengthened relative to the second individual rod (1b), so that with respect to a straight zero position ( c\ ) of the tie rod (1), a bulge transverse to the longitudinal direction ('t. 0) of the rod in both directions (f^ ,f-&zgr;) is possible. 3. Neck rod according to claim 1 or 2, characterized in that the second individual rod (1b) is provided at its second end (1") with a fixed threaded sleeve (5) with an internal thread (L1), that the screw element (4) in the form of a double threaded nut (DG.M) with an external thread (L2) is screwed into the threaded sleeve (5) and that the double threaded nut (4- ) has an internal thread ( R1 ) which is opposite to its external thread (LI ) and into which the second end (1 " ) of the first single rod ) is screwed with an external thread ( R2 ), so that · - 7 - 95/0220 G when the double threaded nut (4-) is rotated in a first direction of rotation (db), the length of the first individual rod (1<ä) can be reduced and when the double threaded nut (A-) <2 is rotated in the opposite direction of rotation (de), the length of the first individual rod (la) can be increased. ^. Truss rod according to claim 3? characterized in that the double threaded nut (4-) is provided on its externally accessible front side (4cO) with a polygon socket, in particular a hexagon socket (4-b) for the attachment of a rotary wrench (&Ggr;7). 5. Truss rod according to claim 3 or M-, characterized by a left-hand thread (LI ₁ Ll) between the threaded sleeve (5) and the double threaded nut (A-) and a right-hand thread (^1.82) between the double threaded nut (A-) and the second end (1" ) of the first single rod (1a ), so that when the double threaded nut (4-) is rotated clockwise or counterclockwise (d^ ^q), the first single rod (1<3 ) can be shortened or lengthened by a change in length increased by adding the two thread pitches. 6. A truss rod according to one of claims 1 to 5, characterized in that the first individual rod (1<3i) is a round rod and the second individual rod (1b) is a flat rectangular rod, one broad side (B) of which faces the first individual rod (13l). 7· Neck rod according to one of claims 1 to 6, characterized in that the fixed connection of the two individual rods (ta, 1b) to one another at their first end (1 ^l ) and between the threaded sleeve (5) and the second individual rod (1b) is a welded or brazed connection (2^6). 8. Truss rod according to one of claims 1 to 7, characterized in that between the threaded sleeve (&dgr; ) and the double threaded nut (4-) there is an M 8 left-hand thread and between - 8 - 95/0220 G Double threaded nut (4-) and first single rod (la) are provided with an M 5 right-hand thread.