JP3858165B2 - Synthetic resin square heat-resistant enclosure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a structure of a bottom portion of a rectangular casing made of a synthetic resin which is biaxially stretch blow molded and heat resistance is given by heat setting.
[0002]
[Prior art]
As shown in FIG. 4, the bottom part of the synthetic resin biaxially stretched blow-molded housing forms a depressed central portion 11 that is recessed in a substantially hemispherical shell shape at the center, and is formed around the depressed central portion 11. In general, a grounding portion 8 ′ having a surface grounding structure is formed in a ring shape between the tapered wall portion 13 and the rising cylindrical wall portion 14 constituting the connecting portion with the trunk portion. .
[0003]
The structure of the grounding portion 8 ′ is the same regardless of whether the casing is square or heat resistant by heat setting, and is formed into a ring shape with an equal width.
[0004]
[Problems to be solved by the invention]
However, in the above-described prior art, when the housing has a square structure, the grounding portion 8 'facing the flat wall portion 5 of the housing body and the grounding facing the corner wall portion 6 of the housing. There is a difference between the portion 8 ′ portion and the grounding portion 8 ′ portion facing the square wall portion 6 that the extension amount is larger than the grounding portion 8 ′ portion facing the flat wall portion 5. According to the difference in thickness, the moldability and the degree of thermal deformation are clearly different, and the deformation generated thereby becomes an illegal deformation and the “sitting” becomes worse.
[0005]
In addition, when heat setting is performed to give heat resistance, the grounding portion 8 ′ facing the flat wall portion 5 also has good moldability and good moldability of the entire bottom portion. Since the body is released in a relatively high temperature state, the heat of the grounding portion 8 ′ portion facing the flat wall portion 5 is thicker than the grounding portion 8 ′ portion facing the corner wall portion 6. There has been a problem that the amount of shrinkage becomes large, which causes a large irregular deformation at the bottom.
[0006]
Furthermore, in the heat-resistant square frame that has been reduced in weight, the formability is improved due to its thinness, and extremely high formability can be obtained in combination with the improvement in formability by heat setting. Further, since the thickness of the ground contact portion 8 'facing the corner wall portion 6 is greatly reduced, the amount of heat shrinkage after the release becomes larger than in the above case, and the defective product due to the poor "sitting" at the bottom. There was a problem that the incidence increased.
[0007]
Therefore, the present invention was devised to solve the above-described problems in the prior art, and the bottom of a synthetic resin square casing that was biaxially stretch blow molded and heat-resistant by heat setting was improper. An object of the present invention is to obtain a biaxially-stretched blow-molded heat-resistant rectangular housing made of synthetic resin that has a technical problem of preventing the occurrence of deformation and exhibits a stable and good “sitting” function.
[0008]
[Means for Solving the Problems]
The means of the present invention for solving the above technical problem is:
The bottom part of the bottom part of the bottom part of the cylindrical part made of a synthetic resin that is biaxially stretched and blow-molded with a heat-set heat-set, and has a cylindrical part. Being related to structure,
Forming a grounding portion between the tapered wall portion formed around the central depression center portion of the bottom portion and the rising cylindrical wall portion;
This grounding part is located opposite to the flat wall part of the trunk part, and is located opposite to the flat wall part grounding part having a narrow surface grounding structure and the square wall part of the trunk part, A corner wall facing grounding portion having a grounding structure;
It is in.
[0009]
Among the grounding parts at the bottom, the flat wall facing grounding part has a narrow surface grounding structure, so the part where the flat wall facing grounding part is located has a line grounding structure. Compared with the case, the amount of stretching becomes larger, and the thickness becomes thinner and relatively good moldability is exhibited.
[0010]
On the other hand, among the grounding portions at the bottom, the corner wall facing grounding portion has a linear grounding structure, so that it is in a locally stretched state and is formed extremely thin with good formability.
[0011]
Further, since the casing is subjected to a heat setting process at the time of biaxial stretch blow molding, the overall formability is improved, and thereby the bottom formability is sufficiently high. It will be a thing.
[0012]
In this way, the bottom portion is molded with a sufficiently high formability, but there is no change in that the amount of extension of the flat wall facing grounding portion is smaller than that of the corner wall facing grounding portion. Therefore, the amount of heat shrinkage deformation after release remains larger in the flat wall portion facing ground portion than in the square wall portion facing ground portion.
[0013]
However, since the corner wall facing grounding portion is in a locally stretched state and is extremely thinly molded, if the mold is released with a relatively high temperature in a heat-set state, the mold surface of the mold Since it contracts and deforms in a “shrink” shape at the moment of separation, the entire grounding portion of the bottom portion is equally contracted and deformed between the flat wall portion facing ground portion and the corner wall portion facing ground portion.
[0014]
This tendency increases with the degree of thinning of the bottom, so that the lighter the casing, the more pronounced the action.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
A square casing 1 according to the present invention is a heat-resistant casing made of synthetic resin and biaxially stretched and blow-molded, and has a mouth tube section 2 continuously provided through a shoulder section 3 having a tapered rectangular cylinder shape at the upper end. The body 4 having the bottom 7 connected to the lower end has a square wall structure with a square shape, with the flat wall 5 and the ridge line part being the square wall 6.
[0016]
Each flat wall portion 5 of the body portion 4 having the rectangular tube shape is recessed with a panel wall portion for absorbing reduced pressure as in the prior art, and a buckling strength is provided at the center portion of the body portion 4. A central circumferential groove is provided to increase the height.
[0017]
The bottom portion 7 is depressed toward the inside of the housing at the center, and the depressed central portion 11 is provided with thick rib-shaped reinforcing ribs 12 along the radial direction at equal intervals along the circumferential direction. A tapered wall portion 13 that gently slopes downward is provided continuously from the peripheral edge of the depressed central portion 11, and the rising cylindrical wall portion that is provided continuously to the peripheral edge of the tapered wall portion 13 and the lower end edge of the body portion 4. A grounding portion 8 is formed between the lower end edge of 14.
[0018]
The grounding portion 8 is opposed to the flat wall portion 5 of the trunk portion 4 (located immediately below the flat wall portion 5) and the square wall portion facing the corner wall portion 6 of the trunk portion 4. The flat wall portion grounding portion 9 has a surface grounding structure (see a solid line in FIG. 3) having a narrow grounding surface. Is a line grounding structure (see the portion indicated by the two-dot chain line in FIG. 3).
[0019]
The flat wall portion opposing grounding portion 9 decreases the width of both end portions as it approaches the square wall portion opposing grounding portion 10 (see FIG. 2), and the grounding portion 8 as a whole has a rectangular tube shape of the trunk portion 4. It has almost the same square shape.
[0020]
【The invention's effect】
Since the present invention has the above-described configuration, the following effects can be obtained.
A flat wall facing grounding portion facing the flat wall portion of the trunk portion and a square wall portion facing the corner wall portion of the trunk portion in the grounding portion of the bottom part of the heat-resisting rectangular housing made of synthetic resin that is biaxially stretch blow molded There is almost no difference in the amount of thermal contraction deformation between the opposing grounding portion, and this effectively prevents the occurrence of inconvenience that the grounding portion at the bottom is illegally deformed and the “sitting” function is deteriorated. be able to.
[0021]
Moreover, even if the heat set process and further significant weight reduction are applied, even if the difference in the degree of thermal shrinkage deformation between the flat wall opposing grounding part and the corner wall opposing grounding part of the grounding part becomes large, the wall thickness is reduced. Due to the increase in “shrink” -like shrinkage deformation at the time of releasing due to promotion, the shrinkage deformation at each part of the grounding part is equal, and thereby the shrinkage deformation of the grounding part is performed without deteriorating the appearance of the grounding part. become.
[Brief description of the drawings]
FIG. 1 is an overall front view showing an embodiment of the present invention.
FIG. 2 is an enlarged bottom view of the embodiment shown in FIG.
3 is an enlarged explanatory view of a main part of the embodiment shown in FIG. 2; FIG.
FIG. 4 is an enlarged bottom view showing a conventional example.
[Explanation of symbols]
1; Square housing 2; Mouth tube part 3; Shoulder part 4; Body part 5; Flat wall part 6; Square wall part 7; Bottom part 8; Grounding part 8 '; Corner wall opposing grounding part 11; depression center part 12; reinforcing rib 13; taper wall part 14; rising cylinder wall part

Claims (1)

A square casing (1) made of a synthetic resin which is biaxially stretched blow-molded and has heat resistance imparted by heat setting, wherein the barrel (4) has a rectangular tube shape, and the barrel (4) The bottom part (7) connected to the lower end with the rising cylindrical wall (14), and the tapered wall part (13) formed around the central depression central part (11) and the rising cylindrical wall part (14). A grounding portion (8) formed between the flat wall facing grounding portion (9) having a narrow surface grounding structure facing the flat wall portion (5) of the trunk portion (4), and the barrel A synthetic resin prismatic heat-resistant casing comprising a corner wall facing ground portion (10) having a line ground structure facing the corner wall portion (6) of the portion (4).

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