JPH04279313A - Hollow molded article and molding method thereof - Google Patents

Abstract

PURPOSE:To provide a hollow article having rigidity capable of sufficiently resisting the cross-sectional deformation when loads are applied, and a molding method thereof. CONSTITUTION:On oppositely faced two end parts of a cavity, resin injection ports 11, 11 and gas injection ports 12, 12 are provided respectively, and resin and gas flowing into the cavity from these resin injection ports 11, 11 and gas injection ports 12, 12 are allowed to join in the central part of the cavity, and further on the hollow inner wall surface 3 of longitudinally directional central part of a hollow article 1 formed in the cavity, an interruption wall 4 or an annular rib 5 is formed that extends inward.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow molded product such as a handle formed by gas injection molding and a method for molding the same.

0002

2. Description of the Related Art Conventionally, hollow molded products such as handles formed by gas injection molding have been shown in FIGS. 5 and 6, for example.

[0003] In order to mold this conventional hollow molded product a,
Resin inlet b and gas inlet c at one end of the cavity
was provided, and resin and gas were injected into the cavity from the resin injection port b and gas injection port c to perform molding.

[0004] In FIG. 5, the symbol d is a gate, and the symbol e is a gate.
is a sprue.

[0005]

[Problems to be Solved by the Invention] However, since the hollow molded product a molded by this conventional molding method has a hollow portion f inside over the entire length in the longitudinal direction, the rigidity of the central portion in the longitudinal direction is low. However, there was a problem that it easily deformed when a load was applied.

[0006] In addition, especially when the hollow molded product a is molded from a soft material, there is a problem that when a load is applied, the cross section becomes flat and easily breaks.

An object of the present invention is to solve the above-mentioned conventional problems. That is, it is an object of the present invention to provide a hollow molded product having a rigidity capable of sufficiently resisting cross-sectional deformation when a load is applied, and a method for molding the same.

[0008]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention is a hollow molded product in which gas injection holes are formed at both ends in the longitudinal direction and extend inward on the hollow inner wall surface at the center in the longitudinal direction. It is assumed that a blocking wall or an annular rib is formed.

[0009] Also, as a molding method, a resin injection port and a gas injection port are provided at two opposing ends of the cavity, and the resin and gas flowing into the cavity from these resin injection ports and gas injection port are are joined at the center of the cavity to form a blocking wall or annular rib extending inward on the hollow inner wall surface of the longitudinally central portion of the hollow molded product molded within the cavity.

0010

[Function] The hollow molded product molded by the above molding method has a blocking wall or annular rib extending inward on the hollow inner wall surface at the longitudinal center, so it will not deform in cross section when a load is applied. It has enough rigidity to resist.

[0011]

[Embodiments] Hereinafter, embodiments of a hollow molded product and a method for molding the same according to the present invention will be described with reference to the drawings.

FIG. 1 is a schematic front view showing an embodiment of a hollow molded product molded by the molding method of the present invention;
2 is a cross-sectional view of the hollow molded product in FIG. 1, FIG. 3 is a schematic front view showing another embodiment of the blow molded product molded by the molding method of the present invention, and FIG. 4 is the blow molded product in FIG. 3. FIG.

The hollow molded product 1 of the present invention has gas injection holes 2, 2 formed at both ends in the longitudinal direction, and a blocking wall 4 or an annular rib 5 extending inwardly formed in the hollow inner wall surface 3 at the center in the longitudinal direction. It is something that

The molding method includes providing resin injection ports 11, 11 and gas injection ports 12, 12 at two opposing ends of a cavity (not shown), respectively. 11 and gas injection ports 12, 12 into the cavity are merged in the center of the cavity, and the resin and gas flowing into the cavity are mixed in the center of the cavity, and the resin and gas are inwardly flowed into the hollow inner wall surface 3 at the longitudinal center of the hollow molded product 1 to be molded in the cavity. It forms an extending blocking wall 4 or an annular rib 5.

In FIGS. 1 and 3, numerals 13 and 13 are gates, numeral 14 is a runner with these gates 13 and 13 provided at both ends, and numeral 15 is a longitudinal center of this runner 14. It is a spool provided in the section.

The hollow molded product 1 on which the blocking wall 4 is formed is shown in FIGS. 1 and 2, and the hollow molded product 1 on which the annular rib 5 is formed is shown in FIGS. 3 and 4.

Resin flows into the runner 14 from the spool 15, and the gates 13, 1 at both ends of the runner 14
3, resin is injected into the cavity via resin injection ports 11, 11.

At the same time, gas is injected from the gas injection ports 12, 12. Then, the resin and gas flow from both longitudinal ends of the cavity toward the center, and the resin and gas are combined at the longitudinal center of the cavity.

As a result, a blocking wall 4 or an annular rib 5 extending inward is formed on the hollow inner wall surface 3 of the longitudinally central portion of the hollow molded product 1 molded within the cavity.

As described above, a blocking wall 4 extending inwardly is formed on the hollow inner wall surface 3 of the longitudinally central portion of the hollow molded product 1.
Alternatively, since the annular rib 5 is formed, the hollow molded product 1 has a rigidity that can sufficiently resist cross-sectional deformation when a load is applied.

[0021]

As explained above, according to the present invention, a blocking wall or annular rib extending inward is formed on the hollow inner wall surface at the longitudinal center, so that cross-sectional deformation is prevented when a load is applied. It is possible to provide a hollow molded product having sufficient rigidity to withstand resistance and a method for molding the same.

[Brief explanation of the drawing]

FIG. 1 is a schematic front view showing an embodiment of a hollow molded product molded by the molding method of the present invention.

FIG. 2 is a sectional view of the hollow molded product in FIG. 1.

FIG. 3 is a schematic front view showing another embodiment of a hollow molded product molded by the molding method of the present invention.

4 is a sectional view of the hollow molded product in FIG. 3. FIG.

FIG. 5 is a schematic front view of a hollow molded product during molding by a conventional molding method.

FIG. 6 is a sectional view of the conventional molded product in FIG. 5;

[Explanation of symbols]

1 Hollow molded product 2 Gas injection hole 3 Hollow internal wall surface 4 Blocking wall 5 Annular rib 11 Resin injection port 12 Gas inlet

Claims (2)

[Claims] 1. A hollow molded product, characterized in that gas injection holes are formed at both ends in the longitudinal direction, and a blocking wall or annular rib extending inward is formed on the hollow inner wall surface of the central portion in the longitudinal direction. [Claim 2] A resin injection port and a gas injection port are provided at two opposing ends of the cavity, and the resin and gas flowing into the cavity from the resin injection port and the gas injection port are directed to the center of the cavity. A method for molding a hollow molded product, which comprises merging them together to form a blocking wall or annular rib extending inward on a hollow inner wall surface of a longitudinally central portion of the hollow molded product molded within a cavity.