JPH06114917A - Structure for fastening blow-molded hollow body - Google Patents

Abstract

PURPOSE:To improve the fastening strength of a threaded member by eliminating a decrease in the strength of the member due to a reduction in thickness of a threaded fastening part of a blow-molded hollow body. CONSTITUTION:A blow-molded plastic hollow body 1 has a structure in which a bracket 7, etc., is fixed by a screw member 8. A recess part 4 recessed toward a hollow part 3 is formed on a wall 2 of the body 1. Grooves 5 integrally connected to the part 4 to be radially extended in a slender state are formed. The member 8 is fastened to the part 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blow-molded hollow body that constitutes an electric device, a housing panel for furniture, an air conditioning duct, an automobile part such as a console box, a carrying case, and the like. The present invention relates to a structure fixed by a screw member.

[0002]

2. Description of the Related Art As a structure in which other members are fixed to a blow-molded plastic hollow body by using a screw member, a tapping screw concave portion which is recessed toward the hollow portion is formed on a wall surface of the plastic hollow body. What fixes a screw member to a tapping screw recess is described in Japanese Utility Model Laid-Open No. 122223/1990.

[0003]

In the above-mentioned conventional structure for fixing a hollow body made of plastic, a recess for fixing a tapping screw is formed in the step of blow molding the hollow body, and this recess is a projecting cavity. Since the parison is formed to be recessed, the resin at the base end of the recess protruding from the wall in the direction of the hollow part has a high degree of resin extension, and that part becomes thin, and the fixing strength of the screw member decreases. There is.

An object of the present invention is to eliminate the above-mentioned conventional drawbacks, eliminate the decrease in the fixing strength due to the thin portion of the screw fixing portion, and further improve the fixing strength. Is.

[0005]

[Means for Solving the Problems] The present invention is configured as follows to achieve the above object. The first configuration is
In a structure in which another member is fixed to a blow-molded plastic hollow body by using a screw member, a recessed portion that is recessed in the hollow portion direction is formed on the wall surface of the plastic hollow body, and the recessed portion is connected to this recess This is a blow-molded hollow body fixing structure in which a recessed groove that extends outwardly is formed and a screw member is fixed to the recess.

The second structure is a structure in which another member is fixed to a blow-molded plastic hollow body by using a screw member, and a slit groove recessed toward the hollow portion is formed on the wall surface of the plastic hollow body. This is a blow-molded hollow body fixing structure in which a screw member is formed and fixed to the slit groove.

The third structure is a structure in which another member is fixed to a blow-molded hollow plastic body by using a screw member, and the hollow wall of the plastic body is dented toward the hollow portion to face the opposite wall surface. The blow-molded hollow body has a fixing structure in which a welded recess is formed by welding, a recess is formed in a portion of the facing wall corresponding to the weld recess, and a screw member is fixed in the recess.

[0008]

According to the present invention, is it possible to form a recessed portion that is recessed in the direction of the hollow portion on the wall surface of the plastic hollow body, and is formed a recessed groove that is continuous with the recessed portion and extends outwardly? Or, since the slit groove is formed on the wall surface of the hollow body, unlike the case where the concave portion for fixing the screw member is formed in a protruding shape at the time of blow molding, the degree of elongation of the resin at the base end is not particularly high, and the concave portion is not formed. Or the base end of the slit groove does not become thin.
Therefore, the fixing strength of the screw member is increased. In addition, in the case of the slit groove, since the fixing portion of the screw member extends over substantially the entire length thereof, the flexibility of the fixing portion becomes high. In a case where a hollow body is provided with a welding concave portion which is recessed in the direction of the hollow portion and is welded to the opposing wall surface, the welding portion becomes thick and the fixing strength for fixing the screw member to the welding portion becomes high. .

[0009]

Embodiments of the present invention will be described with reference to the drawings.

[First Embodiment] FIG. 1 to FIG. 3, FIG. 5 and FIG. 6 show a first embodiment of the present invention. Figure 1
In FIG. 2 and FIG. 2, 1 is a hollow plastic body, and the hollow body 1 is formed by blow molding a thermoplastic resin. The hollow body 1 is composed of polyethylene, polypropylene, ABS resin, polyamide, styrene-modified polyphenylene oxide, hard thermoplastic such as polycarbonate, or the like. The wall surface 2 of the hollow body 1 is formed with an annular recess 4 slightly smaller than the thread diameter of the screw member recessed in the direction of the hollow 3, and the recess 4 has a recess extending outwardly. Grooves 5 are formed continuously in a radial direction in three directions. The width of the portion of the groove 5 that is continuous with the recess 4 is smaller than the diameter of the annular recess 4. Reference numeral 6 denotes the other wall surface of the hollow body 1, which is integrally welded to the concave portion 4 during blow molding. Reference numeral 7 is a bracket, and this bracket 7 is an example of another member fixed to the plastic hollow body 1. The bracket 7 includes the screw member 8 and the hollow body 1.
It is fixed as shown in FIG. 2 by screwing it into the concave portion 4. The screw member 8 is a self-tapping screw.

FIG. 3 shows a blow molding mode of the hollow body 1 shown in FIGS. 1 and 2. FIG. 4 shows a conventional blow molding mode corresponding to FIG. 9, 1
Reference numeral 0 is a split mold, 9A is a slide mold, and 11 is a parison, and one split mold 9 has a bulged cavity 12 that forms the concave portion 4 and the concave groove 5. The cavity 12 is composed of a protrusion 13 that forms the concave portion 4 and an inclined portion 14 that widens from the tip portion to the base end portion, and the inclined portion 14 is for forming the concave groove 5. As shown in FIG. 3, when the parison 11 is arranged between the split molds 9 and 10 and the split molds 9 and 10 are closed, the parison 11 is deformed as shown by an imaginary line in FIG. In this step, the resin around the concave portion 4 formed by the protruding portion 13 is deformed while being supported by the inclined portion 14, so that if the extension degree of the resin at the base end portion forming the concave portion 4 is finally high. No
The part does not become thin and the parison 11 does not break. In addition, as shown by the virtual line, Paris 1
After molding 1, the slide die 9A is retracted to take out the molded product, and the molding is completed. In the conventional structure shown in FIG. 4, since the cavity 12 forming the recess 4 is only the protrusion 13, the resin at the base end a of the recess 4 has a particularly high degree of extension, as indicated by the phantom line. The part becomes thin and the strength is reduced, and the parison 11 is liable to be broken, resulting in a high defective molding rate.

5 and 6 show modified examples of the first embodiment. FIG. 5 shows an example in which the concave grooves 5 are radially formed in four directions of the concave portion 4, and the tip portion 5A of the concave groove 5 does not reach the tip portion 4A of the concave portion 4. 6 shows an example in which the concave groove 5 is formed in two directions of the concave portion 4, and the concave groove 5 in the two directions is a substantially slit groove. When the short screw member 8 is fixed to the concave portion 4, the concave portion 4 does not necessarily have to be welded to the other wall surface 6 as shown in FIG. The length may be such that the screw member 8 penetrates the portion. The screw member 8 is a self-tapping screw, a wood screw, or a mounting member having a screw structure at its tip.

[Second Embodiment] FIGS. 7 to 10 show a second embodiment of the present invention. In this second embodiment,
Except for forming the slit groove 15 on the wall surface 2 of the hollow body 1, it has the same configuration as that of the first embodiment, and the same components are given the same reference numerals and the description thereof is omitted. The slit groove 15 has a wall surface 2
Is formed by being recessed in the direction of the hollow portion 3 and the other wall surface 6
Is welded to. The slit groove 15 has a width suitable for fixing the screw member 8, that is, a width slightly smaller than the maximum peak diameter of the screw member 8. Slit groove 15
Need not necessarily be welded to the other wall surface 6.

The second embodiment is blow molded as shown in FIG. That is, when the parison 11 is arranged between the split molds 9 and 10 and the split molds 9 and 10 are closed,
The parison 11 is molded as shown by a virtual line in the figure.
In this step, since the slit groove 15 is formed by the long plate-shaped protrusion 16, the resin in the slit groove portion 15 does not have a partially increased degree of extension, and the slit groove 15 is It does not become thin and the parison 11 does not break. The basic molding method is the same as in the first embodiment.

In the second embodiment, as shown in FIG. 10, the screw member 8 is fixed to the slit groove 15. As shown in this figure, the screw member 8 has a slit groove 1
It is possible to fix a large number at any place over substantially the entire length of 5. Further, even in the screw member 8A having a large mountain diameter, since the resin wall exists in the direction of the slit groove 15, the fixing strength is maintained by the wall thickness t of this wall.

[Third Embodiment] FIGS. 11 and 12 show
A third embodiment of the invention is shown. The third embodiment is the same as the first embodiment except that the slit-shaped concave groove 17 is formed on the one wall surface 2 of the hollow body 1 and the slit-shaped concave groove 17 is welded and integrated to the other wall surface 6. The configuration is the same as that of FIG. In the third embodiment, a hole 19 is formed corresponding to the welded portion 18 of the slit-shaped groove 17 on the other wall surface 6, and the screw member 8 is fixed to the hole 19. Groove 1 on the other wall 6
The welded portion 18 of No. 7 is thick.

In the third embodiment, the concave groove 17 does not have to be slit-shaped, and the concave portion of the one wall surface 2 is welded to the other wall surface 6, and corresponding to the welded portion 18. It suffices that the other wall surface 6 be provided with holes 19.

FIG. 13 illustrates a housing 20 of an electric control device using the hollow body 1 according to the second embodiment as a door. In the figure, each device unit 21 and bracket 22
Are respectively fixed to the slit groove 15 by a plurality of screw members 8. 23 is a code.

[0019]

According to the first, second and third inventions of the present invention, it is possible to further improve the fixing strength by eliminating the decrease in the fixing strength due to the thin portion of the screw fixing portion. You can Particularly, according to the second invention and the third invention of the present invention, the arbitrariness of the fixing portion can be greatly improved in addition to the improvement of the fixing strength. Therefore, when the conventional self-tapping screw is used, fixing to the same position again has a problem in strength, but according to the present invention, it is possible to shift the position in the vicinity and fix again.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a part of a blow-molded hollow body showing a first embodiment according to the present invention.

FIG. 2 is an enlarged sectional view taken along the line AA in FIG.

FIG. 3 is a schematic cross-sectional view showing a blow molding aspect of the one shown in FIGS. 1 and 2.

FIG. 4 is a schematic cross-sectional view showing a conventional blow molding mode corresponding to FIG.

FIG. 5 is a partial perspective view showing a modified example of the first embodiment according to the present invention.

FIG. 6 is a partial perspective view showing another modification of the first embodiment according to the present invention.

FIG. 7 is an exploded perspective view of a part of a blow-molded hollow body showing a second embodiment according to the present invention.

FIG. 8 is an enlarged sectional view taken along line BB in FIG.

9 is a schematic cross-sectional view showing a blow molding aspect of the one shown in FIGS. 7 and 8. FIG.

FIG. 10 is a partial front view of the second embodiment according to the present invention.

FIG. 11 is an exploded perspective view of a part of the blow molded hollow body showing the third embodiment according to the present invention.

12 is an enlarged sectional view taken along line C- in FIG.

FIG. 13 is an overall perspective view of an electric control device using a blow-molded hollow body according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hollow body 2 Wall surface 3 Hollow part 4 Recessed part 5 Recessed groove 6 Other wall surface 7 Bracket 8 Screw member 9,10 Split mold 11 Paris 12 Cavity 13 Projection part 14 Inclined part 15 Slit recessed groove 16 Long plate-shaped protruding part 17 Slit -Shaped concave groove 18 Welded portion 19 Hole

Claims (3)

[Claims] 1. In a structure in which another member is fixed to a blow-molded plastic hollow body by using a screw member, a recessed portion that is recessed toward the hollow portion is formed on the wall surface of the plastic hollow body, and the recessed portion is formed. A blow-molded hollow body fixing structure, characterized in that a concave groove extending outwardly is formed continuously with the concave groove, and a screw member is fixed to the concave portion. 2. In a structure in which another member is fixed to a blow molded plastic hollow body by using a screw member, a slit groove recessed toward the hollow portion is formed on the wall surface of the plastic hollow body, and the slit is formed. A blow-molded hollow body fixing structure, wherein a screw member is fixed to the groove. 3. In a structure in which another member is fixed to a blow-molded hollow plastic body by using a screw member, a welded recess is formed by recessing the plastic hollow body in the direction of the hollow portion and welding the opposite wall surface. And a screw member is fixed to the hole by forming a hole in a portion of the facing wall corresponding to the welding concave portion and fixing the screw member to the hole.