JPS6150776B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for manufacturing a composite structure used as a component of a frame of a piano or the like.

(Prior art) Recently, keyboard instruments such as pianos with woodgrain patterns (fabric coating) on the exterior have become widespread. So far, we have adhered a thin wood grain decorative board to the surface of the core material such as plywood that is the component part, applied the desired colored or non-colored transparent paint on top of it, and then applied a glossy finish to reveal the wood grain pattern. I try to do that.

(Problems to be Solved by the Invention) By the way, the conventional method described above requires many steps such as undercoating, intermediate coating, intermediate polishing, top coating, and final polishing, and in the case of finishing work, as shown in Fig. 1. Large parts such as the roof plate a, front plate b, or side plate c of a piano can be finished using a machine such as a belt sander, but
In addition, small parts such as the end base f have shape problems and are difficult to machine, so they naturally rely on manual processing, which is laborious and takes a considerable number of days to complete, and requires the use of organic solvents. The working environment is not good due to the dissipation of dust, and improvements are desired.

Therefore, the purpose of this invention is to obtain a composite structure that can easily express wood grain patterns on small parts such as piano arms, clapboards, and gables without the need for the conventional troublesome painting work or finishing process. shall be.

(Means for Solving the Problems) Based on the above object, the present invention provides an adhesive that becomes transparent upon curing to attach a wood-grain decorative board to a required inner surface of a suitably shaped box-shaped skin body made of a transparent synthetic resin. The skin body is placed in a mold, the required amount of liquid polyurethane resin is injected into the inside of the skin body, a wooden core material is placed on top of it, and the mold is then placed in a lid mold. It is characterized in that it is sealed, the polyurethane resin is foamed, and the core material and skin body are integrally molded with the wood grain decorative board interposed therebetween.

(Example) The example will be explained with reference to the drawings.
In Fig. 3, reference numeral 1 is a skin body for making piano beaters, which is made of a transparent synthetic resin such as AS resin or acrylic resin and is shaped like a box with an open top surface (bottom surface when in use). On the inner peripheral surface of the skin body 1, other than the rear end surface (which is the front end in FIG. 3) that is hidden by the container body, that is, on the inner surface of the part that is exposed to the outside in the state of use,
Wood grain decorative boards 2 made of thin board pieces are successively glued together with an adhesive that becomes transparent upon curing, such as an epoxy adhesive, and then the above-mentioned skin body 1 is attached as shown in FIG. 4A.
is placed in the recess of the mold D, a required amount of liquid polyurethane resin 4a containing a foaming agent is injected into the skin body 1, and a wooden core material 3 smaller than the skin body 1 is placed on top of the resin 4a. Place it on the lid, and then cover it as shown in the same figure (b).
Da is applied, the mold D is sealed, and the polyurethane resin 4a is foamed, a foamed resin layer 4 is formed between the wood grain decorative board 2 and the core material 3, and the skin body 1 and the core material 3 are fixed together. do.

Figure 2 shows the composite structure thus obtained.
The wood grain of the decorative board 2 is exposed through the transparent skin body 1. Then, divide this into two along the line X-X in the same figure, and use the wider side as the treble-side clapboard and the narrower side as the bass-side clapboard, with the cut surfaces of each in contact with the side plate c. .

In addition, in the above example, a case was explained in which the box-shaped skin body 1 was made into a rectangular parallelepiped to produce a clapboard.
Not limited to this, other small parts can be made in the same way by taking an appropriate outer shape, and this invention is applicable not only to piano parts but also to the production of general furniture parts. .

(Effects of the Invention) As described above, according to the present invention, it is possible to omit the complicated and unhygienic painting and finishing processes that are divided into multiple stages as in the past, and even finish small parts. It is efficient because it can significantly shorten the number of days required for production, and it is also possible to mass produce products with uniform quality at low cost.The small parts produced have a transparent skin. The natural wood grain is exposed, giving a sense of quality, and the paint won't crack even after long-term use.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view of the piano. FIG. 2 is a partially cutaway perspective view of a composite structure manufactured according to the present invention. FIG. 3 is an explanatory diagram of a state in which a wood grain decorative board is attached to a skin body. FIGS. 4A and 4B are cross-sectional views showing the manufacturing state. In the figure, 1... skin body, 2... wood grain decorative board, 3...
...Core material, 4...Polyurethane foam resin layer, 4a...
...Liquid polyurethane resin.

Claims (1)

[Claims] 1. A wood grain decorative board is adhered to the required inner surface of a suitably shaped box-shaped skin made of transparent synthetic resin with an adhesive that becomes transparent upon curing, the skin is housed in a mold, and the interior of the skin is The required amount of liquid polyurethane resin is injected into the resin, and a wooden core material is placed on top of it.
A method for manufacturing a composite structure, characterized in that the mold is then sealed with a lid mold, the polyurethane resin is foamed, and the skin body and core material are integrally molded with the wood grain decorative board interposed therebetween.