KR100419181B1 - Electric guitar or piano with a body made of polyurethane foam - Google Patents

Abstract

The present invention provides a musical instrument having a fuselage manufactured by molding a synthetic resin material, the instrument may be an electric guitar or piano, the entire body portion of the instrument is made of polyurethane foam material of specific gravity 0.3 ~ 0.9 Molded, the polyurethane foam may include 5 to 8% by weight of porous particles selected from the group consisting of wood powder, silica and mixtures thereof having an average particle diameter of 1 to 50 μm. In addition, according to the present invention there is provided an exterior case for an amplifier or an electric guitar exterior case molded from the polyurethane foam material.

Description

Electric guitar or piano with a body made of polyurethane foam

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to musical instruments and / or acoustic devices manufactured from polyurethane foam materials. Specifically, the present invention relates to an entire body including, for example, a body part and a neck part of musical instruments such as an electric guitar and a piano. Manufactured using conventional wood by integrally molding a case of an acoustic device such as an instrument case or an amplifier by integrally forming a polyurethane foam material having excellent molding processability and not causing distortion or cracking after molding. The present invention has a main body which can shorten the time required for the manufacturing process and reduce the manufacturing cost, and the sound performance emitted therefrom also relates to the conventional good musical instruments and / or accessory sound equipment.

Various conventional musical instruments, such as electric guitars, pianos, and the like, have been manufactured using expensive wood selected carefully. In order to use such wood according to a conventional method, for example, in the fuselage of an electric guitar, especially an electric guitar, the wood is dried and standardized in a drying kiln, and then glued to a rough outline of the guitar, and then to an electric guitar. It has to go through a complex process of machining to have the necessary curves and pockets to install the necessary electronics.

However, in order to give optimum acoustic performance to wood guitars, the processing conditions must be changed according to the wood, and it takes a lot of time and labor to process the external appearance such as cutting and grinding wood. Nevertheless, the high timber disposal rate due to defects in the wood itself was a real challenge.

In order to solve this problem, for example, a plastic resin such as ABS or the like has been molded to manufacture a body part except the neck part of the main body of the electric guitar, and a method of joining the neck part processed with solid wood has been tried.

However, according to the above method, the molding of the body part of the main body part with the resin and the neck part manufacturing with the wood material did not significantly shorten or reduce the overall multi-step working process, and also have been conventionally attempted resin such as ABS. It has been pointed out that the problem is that it is too heavy to manufacture a guitar due to its high specific gravity, distortion and cracking occurs during molding, and as a result, the acoustic performance of the manufactured electric guitar is inferior to that of a conventional wood guitar. .

Therefore, the object of the present invention is to solve the above problems, the moldability is excellent and does not cause distortion or cracking of the fuselage after molding, as well as having a good acoustic performance and can be produced at a reduced cost within a short period of time the synthetic resin body portion It is to provide an electric guitar provided.

Another object of the present invention is to provide an acoustic aid such as a musical instrument case, an amplifier made of the synthetic resin material.

The present inventors have solved the above problems, excellent moldability, no distortion or cracking of the fuselage after molding, good acoustic performance and low cost of production, for example, musical instruments such as electric guitars, pianos and / or the like. Or, for example, as a result of performing various experiments to provide acoustic aids such as musical instrument cases, amplifiers, etc., it was found that the desired purpose can be achieved by using polyurethane foam as a molding resin material. .

1 is a plan view showing an electric guitar manufactured according to a preferred embodiment of the present invention.

Figures 2a to 2x shows the resonance (ring) test results of the electromagnetic foam polyurethane foam according to the present invention.

The present invention relates to a musical instrument having a fuselage part manufactured by molding a synthetic resin material, and according to one aspect of the present invention, the instrument is an electric guitar, the fuselage part (1) of the electric guitar, the fuselage Polyurethane having a specific gravity of 0.3 to 0.9 as a whole of the main body portion 4 including the neck portion 2 connected to the portion 1 and the head portion 3 provided at the end region of the neck portion 2 to fix the string. There is provided an electric guitar having a body portion molded from a polyurethane foam material, characterized in that it is molded from a foam material.

Polyurethane foam constituting the body portion of the electric guitar according to the present invention may include porous particles selected from the group consisting of wood powder, silica and mixtures thereof, the content of the porous particles constitute the body portion of the electric guitar 5 to 8% by weight based on the total weight of the polyurethane foam is preferred, the average particle diameter of the porous particles is preferably 1 to 50㎛.

According to another aspect of the present invention, in a musical instrument having a main body manufactured by molding a synthetic resin material, the instrument is a piano, the outer body and the interior of the piano body and the whole support leg portion of 0.3 ~ specific gravity There is provided a piano made of a polyurethane foam material, wherein the entire body portion is molded from a polyurethane foam material of 0.9.

According to another aspect of the present invention, there is provided an exterior case for an amplifier molded from a polyurethane foam material having a specific gravity of 0.3 to 0.9.

In addition, according to another aspect of the present invention, there is provided an exterior case for an electric guitar molded from a polyurethane foam material having a specific gravity of 0.3 to 0.9.

In one aspect of the present invention, the fuselage provided in the electric guitar according to the present invention preferably further comprises porous particles to improve the resonance (ring) effect of the fuselage, the porous particles, such as wood powder, silica May be used, and talc, clay, gypsum, and ash may be used in order to reduce cost and strength of the product.

The content of the porous particles added in the body portion of the electric guitar according to the invention is preferably 5 to 8% by weight based on the total weight of the polyurethane foam constituting the body portion of the electric guitar, the average particle diameter of the porous particles When considering the ringing characteristic of the body part, it is preferable that it is 1-50 micrometers.

Hereinafter will be described in detail with reference to the accompanying drawings, in particular with respect to the electric guitar according to the present invention, it should be understood that the same application is also possible for the acoustic equipment auxiliary devices such as piano and amplifier, guitar case.

In Fig. 1, the electric guitar of the present invention is similar to a normal electric guitar in the fuselage part 1 of the electric guitar, the neck part 2 connected to the fuselage part of the electric guitar, and the end of the neck part 2; It is provided with a main body portion 4, which includes a head portion (3) installed to fix the strings of the electric guitar.

As described above, the conventional electric guitar manufactured the body 1 of the electric guitar made of solid wood, but there is a problem that the processing process is long, complicated and expensive. In addition, there has been an attempt to mold the body part 1 with a plastic resin such as ABS resin, but there is a problem that the weight of the body is too large and distortion and cracking of the body occur after molding.

However, the present invention solves this problem by molding the body part 1 using a polyurethane foam having a specific gravity of 0.3 to 0.9.

Polyurethane is a block copolymer composed of a soft segment rich in bendability and a hard segment having a crystal structure by strong intermolecular force, and generically refers to a polymer containing a urethane bond or a urea bond. It means a foamed polyurethane material.

Polyurethane foam material has a relatively small specific gravity, excellent physical properties such as strength, and excellent moldability. Therefore, if the whole body part 4 of the electric guitar is integrally manufactured using this, the warping phenomenon and cracking do not occur after molding. Not only that, there is an advantage that can produce a soft sound than an electric guitar having a body made of wood.

The specific gravity of the polyurethane foam material produced by the electric guitar body part of the present invention is preferably 0.3 to 0.9, more preferably 0.4 to 0.8. If the specific gravity is less than 0.3, it is difficult to manufacture a mold, and it is difficult to satisfy the strength required for fixing the screw used in assembling the body part 1 and the neck part 2 and assembling other parts. If it exceeds the weight of the guitar is too large and the sound is also degraded.

Porous particles may be added to and mixed with the polyurethane foam material constituting the main body portion 4 of the electric guitar according to the present invention. The added porous particles form a predetermined space inside the fuselage part to increase the ringing effect of the fuselage part, thereby providing an effect of improving the acoustic performance of the electric guitar. As such porous particles, for example, wood powder, silica, or the like can be used.

The content of the porous particles added to the material constituting the main body of the electric guitar according to the present invention is preferably 5 to 8% by weight based on the total weight of the polyurethane foam, and the average particle diameter of the porous particles indicates the ringing characteristics of the main body. It is preferable that it is 1-50 micrometers in consideration.

According to the present invention to exemplify a process for producing an electric guitar fuselage using a polyurethane foam material, in particular a rigid polyurethane foam material, the rigid polyurethane foam material is an integral type of the entire body part including the fuselage part and the neck part. It can also be used for molding.

First, the rigid polyurethane polyol resin to which the blowing agent is added and the polyisocyanate are mixed in an appropriate molar ratio, for example, a molar ratio of 1: 1. In this case, when the porous particles are added to the polyol resin, the echo effect of the electric guitar may be improved. Subsequently, the mixture is injected into a mold of the fuselage shape of the electric guitar, and then the injection port is sealed, and heat is applied, or when left at room temperature for a predetermined time, for example, for 10 to 20 minutes, curing proceeds to form foaming to complete molding. . When the mold is demolded, the body part of the electric guitar made of the polyurethane foam material is molded. At this time, the pocket for mounting an electronic device required for the electric guitar may be formed by a mold, but may be processed after molding according to the specification.

The manufactured fuselage portion is coupled to the neck portion through a connecting means like a conventional electric guitar. The neck portion may be integrally formed with the head, but may be separately formed and fixed to the neck portion using fixing means.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the scope of the present invention is not limited to the following Examples.

Example 1: Molding of electric guitar body

To the rigid polyurethane polyol resin (purchased by Shinil Chemical Co., Ltd.) to which the blowing agent was added, 13% by weight of porous particles (silica: FCG, average particle diameter: 30 µm) and optionally a predetermined amount of talc were added to the polyurethane polyol resin. It injected | thrown-in and the polyisocyanate (purchased from Shinil Chemical Co., Ltd.) was mixed in 1: 1 molar ratio here. After the mixture was stirred to mix well, 1.4 kg of the mixed solution was injected into a mold (volume 2.9 L) of the fuselage of an electric guitar, and then the injection port was sealed.

Then, after leaving at room temperature for 15 minutes, the mold was demolded to prepare a body part of an electric guitar fabricated from a polyurethane foam material having a specific gravity of 0.5.

The electric guitar produced was not only light and did not cause distortion or cracking, but also performed sound tests and the sound quality was found to be smooth and excellent. The test was specifically carried out as follows.

Example 2 Physical Properties Test of Molded Polyurethane Foam Specimen

1. Comparison of process duration and cost

Compared to the process and time periods required for the manufacture of the electric guitar wooden guitar according to the conventional method and the electromagnetic guitar according to the present invention.

Comparison between the conventional method and the manufacturing process of the electromagnetic guitar Work process Existing Process When using wood (prior art) Estimated Processing Period The present invention Estimated Processing Period #One Wood screening 0 1 day Molding (0) 1 day #2 Body shape processing 0 1 day # 3 Wood Timber Thought 0 1 day #4 Neck shape processing 0 1 day # 5 Neck Wood Idea 0 1 day # 6 Hado 0 1 day 0 1 day # 7 Sub-polishing 0 1 day 0 1 day #8 Midway 0 1 day × × # 9 Medium polishing 0 1 day × × # 10 normal course 0 1 day 0 1 day # 11 Top Polishing 0 1 day 0 1 day # 12 Polish 0 1 day 0 1 day # 13 Assembly 0 1 day 0 1 day # 14 inspection 0 1 day 0 1 day # 15 Packing 0 1 day 0 1 day Total process 15th 9th

In the above table, O is an essential process and × is an unnecessary process.

In the above working process, the time required for the entire # 1- # 15 process when using wood according to the conventional method is about 15 days, but the process time according to the present invention is 9 days, which is about 40% of the process period. It can be shortened. That is, the present invention has been shown to reduce the 60% of the cost of using the conventional wood and to exhibit an air shortening effect of 40% in time.

2. Sound and sound comparison test

Exam conditions:

1) The test was carried out under the same conditions, using the main body and the neck part molded from wood and polyurethane, respectively.

2) Pickup: 3-single pickup (manufacturer: Seongjin Industry).

3) Kita Prefecture: American-made Tadario Kita Strings

4) Tuning Condition: Tuning with Guitar Tuner, a common tuner.

Sample: 1 product made of wood 1 product made of polyurethane

Test Machine Machine Name: (Audio precision: system 1)

Results: Table 2 below.

As a result, the acoustic test of the guitar made of polyurethane foam and the guitar made of wood showed that there was no difference as the same result was observed in each band.

Annex # 1) Acoustic / frequency analysis data of wooden products (Guitar: A)

# 2) Sound / frequency analysis data of polyurethane products (Guitar: B)

Acoustic comparison test of strings made of solid wood and polyurethane foam material First string Second string Third string Fourth string Fifth string 6th string Timber-1 329.957 246.372 195.104 146.114 109.876 77.3108 Timber-2 329.791 246.261 195.255 146.239 109.813 76.9638 P / U-1 330.055 246.795 196.377 147.261 110.211 77.0498 P / U-2 330.302 246.767 196.295 147.334 109.990 77.0849

3. Flexural strength (bending) comparison test

Exam conditions:

1) Cut the test material made of wood and polyurethane and measure its strength.

2) Comparison of strength with the same standard (size) as the test product

sample:

-Specimen of wood (width * length * height) 5cm × 20cm × 2cm

-Specimens of polyurethane:

a. Polyurethane molded product (specific gravity 0.4)

Size (Width * Length * Height) = 5cm × 20cm × 2cm

Polyurethane Molded Article (specific gravity 0.6)

b. Size (Width * Length * Height) = 5cm × 20cm × 2cm

c. Polyurethane molded product (specific gravity 0.8)

Size (Width * Length * Height) = 5cm × 20cm × 2cm

Test Machine Tester: UNIVERSAL TEST MACHINE

Manufacturer: Oriental Company

Load (KGF) Maximum strength (breaking) ㎏ / ㎠ Bass Wood 117.00 11.73 Molded article (specific gravity 0.4) 143.50 15.65 Molded article (weight 0.6) 266.40 28.94 Molded article (specific gravity 0.8) 390.20 42.82

As a result, the fracture strength was higher than that of the wood in the fracture test than the conventional wood (Bass Wood). That is, the test piece of the present invention is more robust. This means that it is suitable for use in making the product.

4. Warping test (heat resistance / cold resistance) test

Condition:

1) The test was conducted at -30 ° C for 1 hour at + 80 ° C for 1 hour.

2) Wood and polyurethane of the same size were used.

sample:

1) Specimen of wooden specimen (width * length * height) = 15cm × 30cm × 4cm

2) Test article made of polyurethane:

-Polyurethane foam molded products (specific gravity 0.4)

Size (Width * Length * Height) = 15cm × 30cm × 4cm

-Polyurethane foam molded product (specific gravity 0.6)

Size (Width * Length * Height) 15cm × 30cm × 4cm

-Polyurethane foam molded article (specific gravity 0.8)

Size (Width * Length * Height) 15cm × 30cm × 4cm

Test result:

The fifth examination The seventh examination Remarks Bass Wood Start transforming slightly Warping Molded article (specific gravity 0.4) No deformation No deformation After molding for 24 hours at room temperature Molded article (weight 0.6) No deformation No deformation Molded article (specific gravity 0.8) No deformation No deformation

The results showed that there was no distortion than the existing wood (Bass Wood standard). This means that it is suitable to use the product for making guitars.

Musical instruments, in particular electric guitars and pianos of the present invention has a body portion made of polyurethane foam material, excellent moldability, no distortion or cracking of the fuselage after molding, showing good acoustic performance, and low manufacturing cost And can be manufactured by a simplified and shortened workflow. In particular, when the porous particles are added to the polyurethane foam material constituting the main body portion, the resonance (ringing) effect is improved, and the musical instruments having the same may provide excellent acoustic performance.

Claims (7)

The whole body part which consists of a fuselage | body part, the neck part connected to the said fuselage part, and the head part which is provided in the end area of the said neck part, and fixes a string is made of polyurethane foam which has specific gravity 0.3-0.9, wood powder, silica, and mixtures thereof. An electric guitar, wherein the electric guitar is selected from the group consisting of and is formed by including porous particles having an average particle diameter of 1-50 μm. delete The electric guitar according to claim 1, wherein the content of the porous particles is 5 to 8% by weight based on the total weight of the polyurethane foam constituting the main body of the electric guitar. delete The outer body of the piano body, the whole body and the supporting leg parts are selected from the group consisting of polyurethane foam having a specific gravity of 0.3-0.9, wood powder, silica and mixtures thereof, and porous particles having an average particle diameter of 1-50 μm. Piano characterized in that it is molded, including. delete delete