JPH09209644A - Plastic hinge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the need for assembling work and contrive to reduce cost by providing projectingly a column-shaped pivot areas engaged mutually with the adjacent end face of a wing board and a plurality of shaft insertion areas and forming projectingly a spindle in the column-shaped pivot area in such a fashion that it may move slidably integrally in the shaft insertion area. SOLUTION: A plurality of column-shaped pivots areas 1a and cylinder-shaped shaft insertion areas 1b and 2b engaged with each other are formed on the adjacent end faces of a pair of wing boards 1 and 2 while spindles 1a, which penetrate the central axis of the other cylinder-shaped shaft insertion areas 1b and 2b, are projectingly and integrally formed in the column-shaped pivot 1 in the central part. As a result, the spindle is provided projectingly on the end face of the column and the cylindrical part which fits in the spindle is molded by sliding a part (core) of the mold about the structure of a plastic molding die even at right angles with the mold opening direction. This construction makes it possible to finish the molding of a pair of hinges with one shot and thereby eliminate the need for assembling work.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a plastic hinge used for furniture, stationery, personal belongings and the like.

[0002]

2. Description of the Related Art Conventionally, in hinges (or hinges) made of plastic, cylindrical shaft insertion portions are projected on the end faces of a pair of blades so as to alternately mesh with each other, and the cylindrical inner diameter is made of metal. It is customary to insert a pin. Also,
In a plastic pencil case, polypropylene is used for 0.25 over the entire length of the connecting portion between the container and the lid.
It is customary to integrally form a thin plate of about mm and use this as a hinge.

[0003]

Although there are various plastic products having hinges that repeatedly rotate and bend during long-term use, the above-mentioned thin plate-shaped hinges are usually used. Since such a hinge part is made in a flat shape by a plastic molding die, even if the part is bent, the force that always tries to restore it to a flat surface acts on it, which makes it suitable for certain products. When applied, it had the drawback of being inconvenient to use. Moreover, polypropylene, which is a material suitable for plastic hinges, does not always have physical and chemical properties that are satisfactory for every product. Rather, many products require the use of other high-strength and high-rigidity plastics, but such high-strength and high-rigidity materials cannot be used as thin plate hinges.

Further, like a conventional metal hinge, a pair of vanes each having a cylindrical shaft insertion portion are molded with plastic, and a hinge with a metal pin inserted therein has a plastic molding or a metal pin. Since it had to go through the steps of cutting and assembling, it was relatively expensive.

[0005]

SUMMARY OF THE INVENTION The present invention is intended to integrally form a rotary hinge having a structure similar to that of a conventional metal hinge with a plastic, and therefore a structure of a plastic molding die is used. By sliding a part of the mold (core) also in the direction perpendicular to the mold opening direction, a spindle is projected on the end face of the cylindrical part, and the cylindrical part fitted to the spindle can be molded at the same time. It is the one. As a result, the pair of hinges was completed by one-shot molding, and no assembly work was required.

[0006]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described with reference to the drawings. As shown in FIG. 1, a hinge according to the present invention has a pair of blades 1 and 2 having a plurality of cylindrical shaft supporting portions 1a and cylindrical shaft inserting portions 1b and 2b, which are engaged with each other, on the adjacent end surfaces thereof, and a central portion thereof. The other cylindrical shaft inserting portion 1b is attached to the cylindrical shaft supporting portion 1a of
The support shafts 1s and 1s penetrating the central axis of 2b are integrally formed to project. 1d is a hole for a mounting screw.

An embodiment of a die for molding such a hinge which is integrally molded with plastic will be described. The movable side mold plate 10 of the injection molding die includes blade plate cavity portions 11 and 12 for molding a pair of blade plates 1 and 2, a cylindrical shaft support portion 1a, and cylindrical shaft insertion portions 1b and 2b. Cylindrical part cavity 11a and cylindrical part cavity 1 for molding a semicircular part
1b, 11b, 12b, and 12b are provided in the end face of the blade cavity portions 11 and 12 on the adjacent side. Therefore, the cavity partition wall 13 for partitioning between the adjacent cylindrical cavities 11a, 12b, 11b is erected. On the other hand, the fixed side mold plate 20 has the cylindrical shaft support 1
a, cylindrical cavities 21a, 22b, 21b for molding the semi-circular portion on the opposite side of the shaft insertion portions 1b, 2b are provided in a concave position at a position facing the cylindrical cavity provided in the movable side template 10. To do. Also in this fixed-side mold plate 20, a cavity partition wall 23 for partitioning each of the cylindrical cavities 21a, 22b, 21b is erected so as to abut the partition wall 13 of the movable-side mold plate 10. . The cavity partition walls 13 and 23 thus formed are preferably made as thin as possible in terms of strength by hardening the steel material for molds by heat treatment or the like.

Next, in order to project the supporting shaft 1s integrally connected to the cylindrical supporting shaft portion 1a formed by the cavities 11a and 21a through the other cylindrical shaft inserting portions 1b and 2b. The slide cores 31, 31 are fixed to the fixed mold 2
The movable side mold plate 10 is mounted by engaging with the finger pins 30 inserted from 0. This slide core 31, 3
Numeral 1 is a cavity closing process of the mold, cavities 11b, 21b, 1
It has cylindrical cores 31a, 31a penetrating 2b, 22b and reaching the ends of the cavities 11a, 21a. Then, the inner diameter holes 31c, 3 of the cylindrical cores 31a, 31a,
1c serves as a cavity for molding the support shafts 1s, 1s, and the thick portions 31b, 31b of the cylindrical cores 31a, 31a form gaps 1c, 2c between the support shaft 1s and the cylindrical shaft insertion portions 1b, 2b. Further, the cavity partition walls 13 and 23 are in contact with the outer peripheral edges of the cylindrical cores 31a and 31a to separate the respective cylindrical cavity portions, and the shaft support portion 1a and the shaft insertion portion 1 are provided.
b and 2b can be separately molded.

When plastic is injection-molded in the die having the above construction, the molten resin is filled in the cavity from the gate G, and the pair of blades 1 and 2, the columnar shaft supporting portion 1a, and the shaft inserting portion 2 are formed.
b, 1b and the spindle 1s are molded in one shot. Then, when the mold is opened, the slide cores 31 and 31 slide outward (left and right in the drawing) of the mold by the inclined finger pins 30 and 30, and the cylindrical cores 31a and 31a move into the cavities 12b, 22b and 11b, respectively. 21b, so that the molded product can be taken out in the direction perpendicular to the mold surface. In this way, the two blades are used for the spindle 1.
The hinge is molded in the engaged state by s. Further, when the mold is closed again, the slide cores 31, 31 slide by the finger pins 30, 30 toward the center of the mold, and the tips of the cylindrical cores 31a, 31a reach the end faces of the shaft support cavities 11a, 21a. The plastic is ready for injection.

[0010]

The integrally molded hinge obtained by molding as described above is different from the conventional one in that it is manufactured in a completed form without requiring assembly work such as shaft insertion of the rotating portion. Is reduced.

The hinge of the present invention is not limited to the hinge (hinge) shown in FIG. 1, but can be used for hinges of various articles such as the hinge of the connecting portion between the frame R of the glasses and the string F shown in FIG. It can be molded as one piece.

The conventional plastic hinge has been used by forming a plate-shaped bent portion with polypropylene as a material, but in the hinge of the present invention, polyamide, polyacetal or other engineering plastics having excellent strength and sliding performance is used. It will be possible to apply the plastic hinge to products requiring strength.

[Brief description of drawings]

FIG. 1 is a plan view of a hinge showing an embodiment of the present invention.

FIG. 2 is a bottom view of the hinge of FIG.

FIG. 3 is a reference view showing a main part of a molding die for integral molding.

FIG. 4 is a perspective view showing a main part of a slide core of a mold.

FIG. 5 is a perspective view of a main part of an embodiment used as a hinge of glasses.

[Explanation of symbols]

 1, 2 Blade 1a Shaft Support 1b, 2b Shaft Insertion 1s Spindle 10 Movable Side Mold 11, 12 Blade Cavity 11a, 21a Shaft Support Cavity 13, 23 Cavity Partition Wall 11b, 21b, 12b, 22b Shaft Insert Cavity 20 Fixed mold 30 Finger pin 31 Slide core

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[Procedure amendment]

[Submission date] February 3, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Figure 3

[Correction method] Change

[Correction contents]

FIG. 3 is a perspective view showing a main part of a molding die for integral molding.

Claims (1)

[Claims] 1. A cylindrical shaft support part and several shaft insertion parts that engage with each other project from the adjacent end faces of a pair of blades, and the cylindrical shaft support part penetrates through the central axis of the shaft insertion part. A method of manufacturing a plastic hinge, wherein the supporting shaft is integrally and slidably formed in the shaft inserting portion.