JPH04270613A - Joining structure of synthetic resin hollow body - Google Patents

Abstract

PURPOSE:To manufacture a large-sized hollow body by improving strength of joining structure of the hollow body, by a method wherein a dent of a demolding direction and a dent of a direction meeting with the same at right angles are provided in the surfaces of half-split bodies each and molten resin is cast into a space which is formed of those dents by combining them together. CONSTITUTION:While dents 33, 43 of a demolding direction are formed, slide cores 11, 12, 22 moving along a flange surface are provided on a mold registration surface of molds 1, 2 and continued to the dents 33, 42 through the outside of confronting end faces 30, 40 at the time of injection molding of half-split bodies 3, 4, that is, the dents 34, 44 meeting at right angles with the demolding direction are formed. When molten resin is cast into a spatial path R1 through a sprue, flange parts 31, 32, 42 are connected vertically and physically with the molten resin extending to the dents 34, 44 from the dents 33, 43, moreover, it becomes that joining force applies to a joining surface of fringe parts of the half split bodies 3, 4 and joining strength can be made a rapid improvement, which is suitable for joining of the half-split bodies manufacturing a large-sized hollow body.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joint structure for a joint when a hollow body is manufactured by butt-joining injection-molded half bodies.

0002

[Prior Art] Blow molding is a common method for manufacturing hollow containers, but due to the structural strength or shape of the hollow body, primary injection molding is performed on the divided halves. A two-stage molding method has been proposed in which the butted parts are joined by secondary injection molding of resin (Patent Publication No. 2).
-20410). However, when the entire hollow body becomes large and the abutting portions require a certain level of bonding strength, there is a problem in that simply injection molding molten resin for bonding to the abutting portions is not sufficient.

0003

[Problems to be Solved by the Invention] By the way, when trying to manufacture a hollow body by abutting halves, in order to give a constant joint strength to the joint of the hollow body, it is necessary to It is necessary that both joint surfaces engage in the width direction) and the vertical direction (vertical height direction). Therefore, it is an object of the present invention to provide a joining structure that can physically connect upper, lower, left, and right sides of half-split bodies via molten resin at the joint surfaces.

0004

[Means for Solving the Problems] In the direction perpendicular to the die-cutting direction, the present invention provides a sliding structure to be attached to the die and an engaging portion formed in the direction orthogonal to the die-cutting direction. This method was developed based on the fact that the above-mentioned physical engagement can be achieved in conjunction with the engaging portion, and the injection-molded half bodies are brought into contact with each other by abutting their end surfaces against each other in a mold. In a structure in which a molten resin material for joining is injected into the joining part and joined, a recess in the die cutting direction and a recess in a direction perpendicular to this are provided on the end face of each half, and the mold is assembled by these recesses. The joint structure of a synthetic resin hollow body is formed such that the molten resin is injected into the space. In the present invention, since it is easy to form the recess in the die cutting direction over the entire length of the joining end surface of the half body, it is necessary to provide the recess continuously in the longitudinal direction, while the recess in the direction perpendicular to this is provided with a sliding structure. Since this is necessary, it is easy to provide it intermittently in terms of mold design. Here, the recess refers to a recess in which molten resin is accommodated and can exert bonding force, but it may also be formed as a hole or a through hole.

[0005]

[Function] According to the present invention, the abutting end faces are connected by molten resin injected into the recesses formed in the die-cutting direction of each half body, and the physical engagement in the horizontal direction can be achieved, while each half body The molten resin injected into the recesses perpendicular to the mold-cutting direction of the body connects them to achieve vertical physical engagement.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in detail below based on specific examples shown in the accompanying drawings. FIG. 1 is a cross-sectional view showing the molded state of the joining structure of the present invention, showing the state before mold clamping for secondary molding after primary molding of each half of the hollow body. FIG. 2 is an enlarged perspective view of the main parts thereof, FIG. 3 is a sectional view showing a state in which molten resin is injected into the joint structure of the present invention after mold clamping for secondary molding, and FIG. 4 is an enlarged perspective view of the main parts. It is.

In the drawings, 1 is an upper mold, 2 is a lower mold, and hollow halves 3 and 4 are molded in each mold. The half body 3 has flanges 31 and 32 protruding outward from a slightly elevated position on the peripheral edge of the abutting end face 30, and forms a recess 33 in the die cutting direction, while moving back and forth along the flange surface. At the time of injection molding of the half body 1 by attaching slide cores 11 and 12 to the mold matching surface of the upper mold 1, a recess 34 is formed which is continuous with the recess 33 from the outside of the abutting end surface 30, that is, perpendicular to the mold removal direction. form. On the other hand, the half body 4 also has flanges 41 and 42 protruding outward at slightly lowered positions on the peripheral edge of the abutting end surface 40 of the main body, and a recess 4 in the die cutting direction.
3, slide cores 21 and 22 that advance and retreat along the flange surface of the lower mold 2 are attached to the mold matching surface of the lower mold 2, and when the half body 2 is injection molded, the recess 43 is formed from the outside of the abutting end surface 40. A recess 44 is formed which is continuous with the die cut direction, that is, perpendicular to the die cutting direction.

The recesses 33 and 43 in the die cutting direction are formed by flange portions 31 (32) and 41 protruding from the peripheral edge of the half body.
(42) is preferably formed over the entire length in order to facilitate secondary molding of the molten resin and improve bonding strength. On the other hand, in order to improve the bonding strength, it is preferable that the depressions 34, 44 perpendicular to the depressions 33, 43 extending in the longitudinal direction be formed intermittently along the longitudinal direction at appropriate intervals (see Fig. 2). . When the half bodies 3 and 4 are in the abutting state, the recesses 33 and 43 on the flange surfaces are continuous in the longitudinal direction as shown in FIG. It takes the form of intermittently protruding laterally from the space formed by 33 and 43. Therefore, when the molten resin B is injected into the cavity R1 through the spool, the flange portions 31, 32 and 4
1 and 42 are physically connected vertically by molten resin extending from depressions 33 and 43 to depressions 34 and 44,
Then, the joining force of the molten resin acts on the joining end surfaces of the peripheral parts of the half bodies 3 and 4. In the above embodiment, the recesses 33 and 43 in the die cutting direction are flat, but holes penetrating the flange portions 31, 32, 41, and 42 may be formed to enhance the physical engagement force in the width direction. good.

As shown in FIG. 5, when the end surfaces of half bodies 5 and 6 of circular cross-section hollow bodies are thick, as shown in FIG. It is also possible to provide recesses 51 and 61 in the die-cutting direction, and at the same time form recesses 52 and 62 that are continuous in a direction perpendicular thereto. In this case, a portion of the joining end surfaces 50 and 60 forms the innermost portion that is brought into direct contact. Further, as shown in FIG. 7, a recess 53 having an inverted U-shaped cross section, consisting of a recess 53a in the die cutting direction and a pair of recesses 53b in perpendicular directions at both ends thereof, is divided into halves by a correspondingly shaped slide core. It may be formed to span 5 and 6. Furthermore, as shown in FIG. 8, the joint end surface 5 of the half body 5
0 is formed with an outer notch recess 54 in the die cutting direction, while an inner notch recess 64 is formed in the joining end surface 60 of the half body 6 in the die cutting direction, and when the two abut each other, an inverted L-shaped cross section is formed. A hollow space R2 may be formed, and recesses 65 and 55 that are perpendicular to the hollow space R2 and extend over the abutting end surfaces 50 and 60 may be formed by a slide core. Further, as shown in FIG. 9, the joint end surface 50 of the half body 5
A recess 56 is formed in the central part of the half body 6 in the direction of mold removal, while a recess 6 is formed in the central part of the joint end surface 60 of the half body 6 in the direction of mold removal.
6, a continuous cavity R3 is formed in a state where the two abut each other, and depressions 57 and 67 perpendicular to the cavity R3 are formed by slide cores for the half bodies 5 and 6, respectively. good. In short, it is important that the injection of the molten resin creates a structure that physically engages with the recesses, recesses, or holes in the die-cutting direction at least in the die-cutting direction.

0010

As is clear from the above description, according to the present invention, injection molded half bodies are abutted against each other in their end faces in a mold, and molten resin for joining is applied to the abutting portions. In a structure in which material is injected and joined, indentations are provided not only in the die-cutting direction but also in a direction perpendicular to the die-cutting direction on the joint end surface of each half-piece to physically engage the half-pieces in the die-cutting direction. Therefore, the bonding strength can be dramatically improved compared to the bonding force of molten resin alone, and is suitable for joining half bodies for manufacturing large hollow bodies.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the molded state of the joint structure of the present invention;

[Figure 2] An enlarged perspective view of the main parts of Figure 1,

[Fig. 3] A cross-sectional view showing a state in which molten resin is injected into the joint structure of the present invention,

[Figure 4] An enlarged perspective view of the main parts of Figure 3,

[Fig. 5] A cross-sectional view showing the entire case where the joint structure of the present invention is applied to the joint end face of a cylindrical hollow body without a flange.

[Figure 6] Enlarged cross-sectional view of the main parts of Figure 5,

7 is a sectional view corresponding to FIG. 6 showing another embodiment of the present invention applied to the hollow body of FIG. 5,

FIG. 8 is a sectional view corresponding to FIG. 6 of a second modification of the joining structure of the present invention;

FIG. 9 is a sectional view corresponding to FIG. 6 of a third modification of the joining structure of the present invention.

[Explanation of symbols]

1 is an upper mold, 2 is a lower mold, 3 and 4 are hollow halves, 1
1, 12, 21, 22 are slide cores, 30 and 40
is the main body, 31 and 32 are the flange parts, 33 is the through hole, 4
1 and 42 are flange parts, 43 is a through hole, and R1, R2, and R3 are hollow passages into which molten resin is injected.

Claims (2)

[Claims] Claim 1: In a structure in which injection-molded half bodies are joined by abutting their end faces against each other in a mold and a molten resin material for joining is injected into the abutting portions, each half body is A product made of synthetic resin, characterized in that the end face is provided with a depression in the die cutting direction and a depression in a direction perpendicular to this, and the molten resin is injected into the space formed by the combination of these depressions. Joint structure of hollow body. 2. The joint structure for synthetic resin hollow bodies according to claim 1, wherein the depressions in the direction of mold removal are continuous in the longitudinal direction, and the depressions in the direction perpendicular to this are intermittent.