CZ2008396A3 - Reinforcement of acoustic guitar neck using carbon fiber pull rod - Google Patents

Abstract

Reinforcement of the acoustic guitar neck is accomplished by gluing the untreated carbon fiber bundle into a neck cut with a longitudinal groove or grooves using a resin. The number of grooves, their size and the shape of the cross section may vary, depending on the type of acoustic guitar neck. The grooves are filled with resin and the untreated carbon fiber bundles are stretched and placed in a liquid adhesive. For the desired engagement of the composite rod in the neck structure, the fiber bundles need to be kept permanently tensioned until the resin cures. After the resin has cured, the fiber bundles can be pulled off and the neck of the acoustic guitar can be fabricated (subsequent processing of the beaded blank) using standard technology.

Description

The neck reinforcement of the acoustic guitar is accomplished by gluing untreated carbon fiber bundles into the longitudinal slot (s) of the neck using resin. The number of grooves, their size and cross-sectional shape may vary depending on the type of neck of the acoustic guitar. The grooves are filled with resin and the untreated carbon fiber bundles are stretched and placed in the liquid adhesive. For the desired engagement of the composite rod in the neck construction, the fiber bundles need to be kept permanently tensioned until the resin cures. After the resin has cured, the fiber bundles can be unloaded and the production of the acoustic guitar's neck (post-processing of the rod-attached blank) can be finished by standard technology.

CZ 2008 - 396 A3

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Reinforcing the neck of an acoustic guitar with a carbon fiber rod

Technical field

The invention relates to the neck reinforcement of an acoustic guitar, wherein carbon fiber bundles are embedded in a groove or grooves on the pulling side of the neck in a suitable resin. The invention also relates to the number, arrangement and method of manufacturing these reinforcing elements.

BACKGROUND OF THE INVENTION

Strong tension arises in the neck of an acoustic guitar. These stresses cause bending of the neck and increasing the striking of the strings above the acceptable limit, especially under long-term load. The size of the deflection is influenced mainly by the type of strings used and neck stiffness.

The acoustic guitar neck is made of high quality wood with higher rigidity as standard. For example, inserting a longitudinal profile of stiffer material into the center of the neck, or gluing one or more layers of material (eg veneers) longitudinally into the center of the neck is used to further increase neck stiffness. In the construction of the neck of a folk guitar with metal strings is usually placed a steel rod, which is located in the pressure zone of the neck in the groove below the fingerboard.

The carbon fiber construction of the neck appears mainly in electric guitars. For example, shells made of carbon fiber fabric and resin are used on the surface of all or part of the neck. Further, for example, profiles are used which are usually prepared by composite manufacturers by pressing carbon fiber bundles in the resin. The fibers in the profiles are usually oriented in the direction of the neck length. The profiles are bonded to both the tension zones of the neck and the pressure zones under the fingerboard. A fingerboard made entirely of resin-pressed carbon fibers is also used to increase neck stiffness.

Furthermore, a combination of several types of reinforcement is used. Often, the steel rod is combined with a wood profile of high rigidity located longitudinally in the center of the neck. Sometimes the steel rod is combined with a carbon fiber shell and resin placed on the neck surface or part thereof, or with a glued profile of resin-molded carbon fibers.

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SUMMARY OF THE INVENTION

It is an object of the present invention to bond untreated carbon fiber bundles to the neck blank in a single manufacturing step using basic raw materials, which are only carbon fiber bundles and resins.

The invention consists in making a longitudinal groove or several grooves into the blank of the guitar neck in which the carbon fiber bundles are glued in one operation. The cross-section, position of the groove or grooves depends on the type of guitar and neck. The grooves in the blank are then filled with resin and the untreated carbon fiber bundles are stretched and placed in the liquid adhesive. For the desired engagement of the composite rod in the neck construction, the fiber bundles need to be kept permanently tensioned until the resin cures. After the resin has cured, the fiber bundles can be unloaded. The production of the neck of an acoustic guitar (post-processing of a blank with a rod) can be completed with existing technology.

The groove cross-section and the number of fibers in the groove can be adjusted according to the rigidity requirements of the entire neck. However, the groove will always be so deep that the groove depth of the finished neck is approximately 2 mm. This depth plays an important role in the drawbar functionality. Deeper placement of the carbon fiber bundle outside the neck tension zone results in loss of rod efficiency.

The shape of the groove profile can be rectangular, rounded, wedge-shaped or other. A groove with a rounded profile is suitable. This profile shape allows very good bonding of fiber, resin and wood bundles, while at the same time gradual transitions minimize the effect of the groove as a stress flow concentrator under neck load.

An advantage of the invention is the technologically simple bonding of untreated fiber bundles directly into the neck structure of the guitar. It is therefore not necessary to pre-manufacture the profiles by pressing the carbon fibers in the resin and pasting the profiles into the neck blank in a subsequent manufacturing operation. Another advantage of simplifying production by avoiding the use of extruded profiles is the ease and low cost of changing the rod cross section by simply increasing the number of bonded bundles. Slot positions and numbers can also be easily modified. The use of multiple grooves also reduces unwanted sideways bending when the neck is bent.

A disadvantage in comparison with the use of extruded profiles of the same overall cross-section is the lower resulting neck stiffness. However, the stiffness difference is not great, the stiffness of the neck reinforced according to the invention is sufficient and can be easily increased. The disadvantage is also compensated by a reduction in production costs.

From the aesthetic point of view, the handle can be visually accessed by finishing with a transparent lacquer or, alternatively, covered with a strip or veneer strip in accordance with the aesthetic design of the entire tool. It is not expected that the described rod will complicate the possibility of surface finish of the neck and there is no need to worry about any adverse effects when playing the instrument.

Overview of the drawings

The invention is illustrated in more detail by the following schematic drawings. Giant. 1 is an axonometric view showing a cut of a neck of an acoustic guitar with a milled longitudinal groove of a rectangular cross-section. This groove is filled with resin in which the carbon fiber bundle is laid. Giant. 2 is an axonometric view of an alternative with a single rod in the post-neck condition of an acoustic guitar. Giant. 3 is an axonometric representation of a variant of three grooves with glued carbon fiber bundles on the finished neck of an acoustic guitar.

DETAILED DESCRIPTION OF THE INVENTION

In FIG. 1 shows a blank for making a neck of an acoustic guitar, which is made of one, two or even more pieces glued together 3. The carbon fiber bundles 1 are glued into a milled longitudinal groove with a profile 2 by means of resin.

In FIG. 2 shows the entire neck realized with three carbon fiber grooves 1. The blank for making the neck of an acoustic guitar is machined into a round shape. A head 4 and a foot 5 are glued to the continuous element 3. In this case, the carbon fiber grooves 1 are of three pieces with a groove profile 2 of rectangular shape.

In FIG. 3 shows the neck of an acoustic guitar with a glued fingerboard 6. A head 4 and a foot 5 are glued to the continuous panel 3. The continuous longitudinal carbon fiber groove 1 has a profile 2 of semicircular shape.

In FIG. 4A, 4B and 4C, some profile shapes of the groove 2 in the continuous neck panel are shown

3. FIG. 4A shows a round profile of the groove. Giant. 4B shows a rectangular groove profile covered by aesthetic wood strip 8. Giant. 4C shows a wedge profile of a groove in a neck made of two continuous pieces 3. The neck is in all cases completed with a finish 7.

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Patent claims

Claims (4)

A neck reinforcement for an acoustic guitar with a rod made of carbon fiber bundles, characterized in that a longitudinal groove is formed in the neck blank in the tensile zone of the neck, which is then filled with resin and an untreated carbon fiber bundle (1) it remains tensioned by the added force until the resin cures. An acoustic guitar throat groove made according to claim 1, characterized in that the shape and size of the profile (2) of the longitudinal grooves and their number are arbitrary. Acoustic guitar throat rod according to claim 1, characterized in that the rod is visually accessible by finishing the throat with transparent lacquer (7), or vice versa, covered with a strip (8) or a veneer strip in accordance with the aesthetic solution of the entire instrument. A neck tie produced according to claim 1 also used in other stringed musical instruments, characterized in that the placement of the composite tie in the tensile zone of the neck of the instrument will be maintained.