JPH0357465Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to a multicolor molded product produced by a multicolor molding method of synthetic resin.

[Prior art and its problems]

Keyboard keys for typewriters, calculators, etc. are typical examples of conventional multicolored molded products. This key is manufactured by first molding letters and numbers using primary molding, and then secondary molding a different colored resin around the primary molded product (letters, numbers, etc.). The leading edge of the letters and numbers that appear on the surface of the primary molded product comes into contact with the inner surface of the secondary mold during secondary molding, and during secondary molding,
Its shape is kept intact. However, in a portion other than the tip surface, the primary molding resin and the secondary molding resin are partially or completely mixed. This is because the keys only need to have clearly formed characters and numbers on the surface due to their intended use, and there is no need to pay attention to the mixing of the resin inside.

However, the shape, design, and
Depending on the application, there may be problems if not only the surface but also the internal resin does not mix between the primary molded product and the secondary molded product, and the shape of the product also collapses.
For example, if a primary molded product is integrated with a secondary molded product made of transparent or colored transparent resin, and a multicolored molded product is designed so that the transparent secondary molded product can be seen through, the primary molded product becomes the secondary molded product. The transparent resin must not lose its shape or mix together, and the primary molded product and the secondary molded product must be firmly joined. It is also important that the color of the primary molded product does not flow into and mix with the transparent secondary molded product. In addition, for example, when an inner frame having a square shape in plan view is used as a primary molded product, and an outer frame covering the outer periphery and one end surface of the inner frame is integrally resin-molded as a secondary molded product, the outer frame Thermal stress occurs due to temperature changes in the body, and at the same time distortion occurs in the inner frame, which may cause peeling between the joint surfaces of the outer frame and the inner frame. In order to prevent this, it is conceivable to put ribs in the four corners of the frame, but in such a case, sufficient bonding force can be obtained at the joint surface between the outer periphery of the inner frame and the outer frame. The bonding surface between the rib and the outer frame is likely to peel off due to body warping or the like, and this peeling may have a negative visual impact and may impair the aesthetic appearance.

Furthermore, when a rib is provided, the deformation of the inner frame is prevented, but at the joint between the inner periphery of the corner of the inner frame and the outer frame, the direction differs across the angle of the inner frame. Since thermal stress is generated, depending on the direction and magnitude of the thermal stress, non-uniform deformation may occur on the outer frame side, and local peeling may occur.

[Means for solving problems]

In order to solve the above-mentioned problems, this invention includes an inner frame made of resin and having a square shape in plan view, and a transparent inner frame that is fixed to the inner frame so as to cover the outer periphery and one end surface of the inner frame. In a multi-colored molded product having an outer frame body molded from a resin, ribs are provided at four corners of the inner frame body, and one end face of these ribs is located on a diagonal line of the inner frame body. A protrusion having a hemispherical tip is formed in the portion so as to be embedded in the outer frame.

〔Example〕

Figures 1 to 4 show an example of a multicolored molded product of this invention, which is a cover case for a meter or the like. This cover case 1 is shaped like a rectangular, shallow-bottomed valve box, and has a transparent window portion (outer frame body) 2 that covers the scale plate of the meter when it is attached to a meter, etc.
and a rectangular frame (inner frame) 3 that supports the transparent window 2. The transparent window 2 is made of a transparent resin such as acrylic resin, styrene resin, or polycarbonate resin. is made of white opaque resin such as ABS resin, styrene resin, and polycarbonate resin. In this example, the frame portion 3 is a primary molded product formed by primary molding, and the transparent window portion 2 is a secondary molded product formed by secondary molding. Further, here, the frame portion 3 constitutes a primary molded product, and the transparent window portion 2 constitutes a secondary molded product.

The frame portion 3 has a rectangular cross-sectional shape, and reinforcing rib portions 4 are formed in a striped shape at its four corners as shown in FIG. Protrusions 5 each having a substantially hemispherical tip are formed on a diagonal line of the frame 3 among the surfaces of the ribs 4 that are in contact with the transparent window 2 .

The transparent window portion 2 is integrally formed into such a frame portion 3 by secondary molding. FIG. 4 shows a cross section of the case 1 after this secondary molding, in which the peripheral edge 2a at the tip of the transparent window 2 extends from the top surface of the frame 3 in contact with the transparent window 2 to the side surface 3a. While being joined to the frame portion 3, the projections 5 of the rib portions 4 are biting into the transparent window portion 2, so that the two are joined together.

[Effect]

In such a case 1, the ribs 4 prevent the frame portion 3 from deforming, and the projections 5 formed on the upper surface of the ribs 4 engage with the transparent window portion 2, thereby preventing the transparent window portion from deforming. Since the projection 5 and the transparent window part 2 engage with each other by restraining the contraction of the frame part 2 against the upper surface of the frame part 3, the bonding strength between the transparent window part 2 and the frame part 3 increases. This suppresses peeling between the upper surface of the frame 3 and the transparent window 2, and prevents the appearance of the product from being impaired by such a portion.

Furthermore, since the protrusion 5 is located on the diagonal line of the upper surface of the frame part 3, as the protrusion 5 prevents the contraction of the transparent window part 2, the corners of the transparent window part 2 and the frame part 3
Thermal stress generated at the joint portion with the corner portion of the frame portion 3 is symmetrical with respect to the diagonal line of the frame portion 3. Therefore, there is no risk of peeling at the joint between the inner periphery of the corner of the transparent window section 2 and the outer periphery of the corner of the frame section 3, where an equal pressing force is applied across the corner of the frame section 3. .
Incidentally, if the protrusions 5 are not arranged diagonally on the frame 3, the distribution of the thermal stress will be uneven, and as a result, there is a risk that uneven distortion will occur at the corners of the transparent window 2, causing local peeling. be.

Since the tips of the protrusions 5 have a smooth hemispherical shape, the molten resin flowing near the protrusions 5 during secondary molding partially melts the protrusions 5 and flows at the same time, causing color bleeding. This does not occur, and the flow of the molten resin is only slightly inhibited, so that the smooth flow of the resin can be ensured.

[Effect of idea]

As explained above, the multicolored molded product of this invention includes an inner frame body formed of resin and having a square shape in plan view, and a molded article fixed to the inner frame body so as to cover the outer periphery and one end surface of the inner frame body. and an outer frame body molded from a transparent resin, ribs are provided at four corners of the inner frame body, and one end face of these ribs is located on a diagonal line of the inner frame body. Since a protrusion with a hemispherical tip is embedded in the outer frame at the portion located at It is possible to prevent the joint surface between the inner frame body and the outer frame body from peeling off, and also to prevent uneven deformation of the corners of the outer frame body due to the provision of protrusions, so that the inner frame body corners and the outer frame body corners can be separated. Localized peeling can also be prevented, eliminating the risk of damaging the beauty of the product. Furthermore, since the tips of the protrusions are smooth, the tips of the protrusions will not melt during secondary molding and cause color bleeding, and the flow of the molten resin will not be obstructed or disturbed.

[Brief explanation of the drawing]

The drawings show a cover case as an example of the multicolored molded product of this invention; FIG. 1 is a partially cutaway perspective view of the cover case, FIG. 2 is a plan view of the frame,
3 is a sectional view taken along the line -- in FIG. 2, and FIG. 4 is a sectional view of the cover case. 1...Cover case, 2...Transparent window part (outer frame body), 3...Frame part (inner frame body), 5...Protrusion.

Claims (1)

[Scope of utility model registration request] An inner frame body formed of resin and having a square shape in plan view, and an outer frame body fixed to the inner frame body and molded from a transparent resin so as to cover the outer periphery and one end surface of the inner frame body. In the multi-colored molded product, ribs are provided at the four corners of the inner frame, and one end surface of these ribs has a hemispherical tip on a portion located diagonally on the inner frame. A multicolored molded product, characterized in that a protrusion is formed to be embedded in the outer frame.