JPH0727126Y2 - Wood press molding equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention mainly relates to a molding device for wood having a curved surface.

[Background of the invention]

Conventionally, in order to mold wood, the method has been to first steam treat wood to make it wet, then place it on the lower mold and press-mold it with the upper mold.However, if the wood bends, it is curved. The inside is compressed and the outside is expanded. As a result, stress concentrates near the outside of the center of the curved portion, and fracture (cracking) easily occurs from this portion. The Tornet method has been proposed to improve this. As shown in FIG. 4, the Tornet method uses a stainless steel plate or a steel plate as a bottom plate (1) A and has fixing tools (1) B for fixing the wood at both ends. ) The one with C fixed is the fifth
An upper mold (convex mold) (2) A having a molding surface (2 ') A that can be curved convexly downward as shown in the figure, and a concave shape corresponding to the molding surface of the upper mold. It was press-molded by interposing it between a press-molding apparatus having a lower mold (concave mold) (2) B having a molding surface (2 ') B that can be curved. According to the Tornet method, the elongation of wood is restricted by the fixture (1) B, and as a result, the wood (1)
In addition to the vertical pressing force of the upper mold on C, a fixture (1)
The pressing force (compressive force) in the horizontal direction due to B becomes large, and as shown in FIG. 6, cracks or breakage easily occur near the center of the curved portion.

As described above, the molding defects such as cracks and breakages that occur in wood are not limited to the surface of wood, and because they involve internal structural destruction, cracks or breaks appear on the wood surface no matter how it is polished. Deep wrinkles were formed on the inside of the flaws due to the wrinkles, which was very aesthetically unpleasant, and the strength of the wood was also significantly reduced at the molding flaws, forcing its use to be limited.

[Conventional technology]

As a means for improving the Tornet method, as shown in FIG. 7, a cushion spring (2) C which is convexly curved upward is placed on a lower mold (2) B, and the cushion spring ( 2) A method has been proposed in which wood (1) C is placed on and supported by Tornet (1) on C (JP-A-55-63208).

According to the above-mentioned method, at the time of molding, the upward vertical pressing force based on the elasticity of the cushion spring (2) C opposes the downward vertical pressing force of the upper mold (2) A. Since the wood (1) C to be adhered adheres to the molding surface (2 ') A of the upper mold (2) A, the molding accuracy is improved, and the stress that concentrates in the center of the curved portion of the wood (1) C is also a cushion spring. (2) Absorbed by C,
Since they are dispersed, molding defects such as cracks and breakage of the wood (1) C are prevented.

[Problems to be solved by the device]

However, in the above-mentioned conventional method, since the cushion spring is curved so as to be convex upward, it becomes unstable when the wood is placed on the tongue and supported on the cushion spring, and the wood is press-formed. Difficult to set. Cushion springs are usually manufactured by hot or cold rolling steel for springs to produce strips.
The strip is cut into a predetermined size and then heat-treated to be manufactured. However, the strain generated during the heat-treatment increases as the width increases. When a large amount of strain is generated in the cushion spring in this way, the cushion spring does not come into close contact with the tornet and a gap is created between the cushion spring and the tornet, so that the elasticity of the cushion spring cannot be effectively exerted on the wood. Therefore, the above-mentioned conventional method cannot completely prevent cracking, breakage of wood, or return of shape after molding. Therefore, it has been impossible to form a too wide wood by the conventional method.

[Means for Solving the Problems]

The present invention, as means for solving the above-mentioned conventional problems,
An upper mold having a molding surface that is convexly curved downward, a lower mold having a molding surface that is concavely curved upwardly corresponding to the molding surface shape of the upper mold, and a molding surface of the lower mold. The present invention provides a press forming apparatus for wood, which comprises a plurality of flat plate-shaped cushion springs arranged in parallel with each other.

[Operation] In the present invention, since a plurality of cushion springs are arranged in parallel on the molding surface of the lower mold, it is possible to mold wide wood even if the cushion springs are not wide. If the width of each cushion spring is not wide, the elasticity of the cushion spring in the width direction will be uniform.
Further, since the cushion spring has a flat plate shape and is not curved upwardly upward, the wood is stably supported on the cushion spring. Then, when the wood is pressed and bent by the upper mold during molding, the cushion spring also bends along with the bending of the wood, but the cushion spring antagonizes the bending by the returning force based on its elasticity and moves the wood upward. The wood is urged to adhere to the molding surface of the upper mold, and at the same time, the pressing force on the wood of the upper mold is absorbed and dispersed.

[Effect of device]

Therefore, according to the present invention, the wood can be easily set in the molding machine and molded with high accuracy, and molding defects such as cracks and breakage can be effectively prevented.

〔Example〕

The present invention will be described with reference to an embodiment shown in FIGS. 1 to 3. In FIG. 1, (2) is an upper mold (convex mold) having a molding surface (2 ') A that can be curved convexly downward. ) (2) A,
The press molding apparatus is a pressing mold having a lower mold (concave mold) (2) B having a molding surface (2 ') B that can be curved upward in a concave shape corresponding to the shape of the molding surface of the upper mold. Lower mold (concave)
(2) Three cushion plates (21) C, (22) C, (23) C made of stainless steel or steel are arranged in parallel on B. The cushion springs (21) C, (22) C,
(23) The length of C should be the same as or slightly shorter than the length of Tornet (1). In this example, the length of Tornet (1)
1000mm, width 500mm, cushion spring (21) C, (2
2) Each of C and (23) C has a length of 500 mm and a width of 300 to 400 mm. If the width of the cushion spring is 500 mm or less, variation in elasticity in the width direction can be eliminated. Further, as shown in FIG. 2, locking plates (2) D are attached to the four corners of the lower mold (2) B to hold the cushion springs (21) C, (22) C and (23) C.

In order to mold the wood (1) C by the above press molding apparatus, the wood (1) C is steamed to be in a wet state, and the wood (1) C is placed on the tornet (1) to cushion the spring. It is supported on (21) C, (22) C, (23) C.
At this time, the upper mold (convex) (2) A and the lower mold (concave) (2) B
And cushion springs (21) C, (22) C, (23) C
Keep it heated. Next, the wood (1) C is bent while being slowly pressed by the upper mold (convex mold) (2) A.

When the wood (1) C is bent in the above configuration, the wood (1)
In C, wood (1) Upper mold (convex mold) from the upper surface of C
(2) A pressing force is exerted in the vertical direction by A, but in addition to that, the horizontal extension of the wood (1) C is restricted by the fixing tool (1) B of the tornet (1), so that the wood (1) C ) A pressing force is exerted in the horizontal direction from both side surfaces of C, and such a pressing force in the horizontal direction synergizes with the pressing force in the vertical direction by the upper die, so that the wood (1) C is Wood (1) C is the main cause of cracking and cutting from the center, but the above synergistic stress which is the main cause of such molding defects of wood (1) C.
Cushion spring (21) C that bends with
The return force based on the elasticity of (22) C and (23) C antagonizes. In the above-mentioned conventional example in which molding defects occur, the upper surface of the wood (1) C is the molding surface (2 ') of the upper mold (2) A as shown in FIG.
In the case of the present embodiment, the lower surface of the wood (1) C moves upward due to the returning force of the cushion springs (21) C, (22) C, (23) C. As a result of being pushed, the upper surface of the wood (1) C is in close contact with the curved shape of the molding surface (2 ') A of the upper mold (2) A and is continuously curved and molded.

Further, at this time, the heated upper mold and the cushion springs (21) C, (22) C, (23) C naturally come into contact with the wood portion which starts to be bent by the pressing of the upper mold (convex mold) (2) A. However, as a result, the wood part is heated and begins to dry.
Thus, as shown in FIGS. 3 (a), (b), and (c), the parts deformed by press molding are successively dried and solidified to increase the structural strength. This is more effectively prevented, and the stability of the molded shape is great after molding.

In the press molding apparatus of the present invention, a wood molded product having no molding defects such as cracks and breakages can be obtained as described above. Further, the deep wrinkles formed inside the molding defect are evenly dispersed on the surface of the wood to make them inconspicuous, and a very preferable product in terms of appearance can be obtained. In addition, molding defects such as cracks and breaks become structural defects, but products with large structural strength can be obtained because such structural defects do not occur, and products with complicated curved shapes that were extremely difficult in the past. Can be molded without molding defects, and a multi-stage molding method in which an upper mold and a lower mold are combined in multiple stages to produce a plurality of wood molded products at once can be easily applied. Thus, the present invention enables the molding of products with a wide range of applications.

[Brief description of drawings]

1 to 3 show an embodiment of the present invention,
FIG. 1 is a front view, FIG. 2 is a lower mold perspective view, and FIG.
(B) and (c) are state diagrams showing the forming process, FIG. 4 is a perspective view of Tohnet, FIG. 5 is a front view of a conventional press forming apparatus, and FIG. 6 is a front view of a state where a forming defect occurs. FIG. 7 is a front view of a press forming apparatus of an improved conventional example. In the figure, (2) A ... upper mold, (2 ') A ... molding surface,
(2) B ... Lower mold, (2 ') B ... Molding surface, (1) C ...
… Wood, (21) C, (22) C, (23) C …… Cushion spring

Claims (1)

[Scope of utility model registration request] 1. An upper mold having a molding surface that is convexly curved downwards, a lower mold having a molding surface that is concavely curved upwards corresponding to the molding surface shape of the upper mold, and the lower mold. A wood press-molding apparatus comprising a plurality of flat cushion springs arranged in parallel on the molding surface of a mold.