Manufacturing method for inspection hatch receiving frame

Abstract

To provide a manufacturing method for an inspection hatch receiving frame for a clean room, which makes it easier to install a packing and reduces the defective rate compared to conventional methods.SOLUTION: First, A belt-shaped metal plate 6 is bent to form a lower support portion 8 that supports the outer periphery of the lid from below, and a side support portion 9 that supports the outer periphery of the lid from the sides. Next, a packing 4 is disposed on the lower support portion 8 of the belt-shaped metal plate 6 along the longitudinal direction of the belt-shaped metal plate 6. After that, the belt-shaped metal plate 6 and a packing 4 are cut into rod-shaped frame members 2 of a predetermined size, and finally, the ends of the four rod-shaped frame members 2 are welded together to manufacture a rectangular inspection hatch receiving frame.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to an inspection port receiving frame disposed at an underfloor inspection port of a clean room and supporting a lid.

Background Art

[0002] A conventional inspection port receiving frame is composed of four rod-shaped frame members assembled in a rectangular frame shape. In addition, for an inspection port receiving frame disposed at an underfloor inspection port such as in a clean room, since sealing performance of the lid and prevention of rattling are emphasized, packing is disposed at a portion supporting the outer peripheral portion of the lid (see Patent Document 1). Such an inspection port receiving frame is manufactured by welding four metal plate pieces constituting the rod-shaped frame members in a rectangular frame shape and then adhering the packing to the metal plate pieces after welding.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above-described conventional manufacturing method, since the packing is manually attached to the metal plate pieces, the labor for disposing the packing is large, and the occurrence rate of adhesion failure is not small.

[0005] The present invention has been made in view of such a situation, and an object thereof is to provide a manufacturing method in which the disposition of the packing is easy and the defective rate can be reduced as compared with the conventional manufacturing method of an inspection port receiving frame for a clean room.

Means for Solving the Problems

[0006] The present invention relates to a method for manufacturing an inspection port receiving frame for a clean room, which is formed by assembling four rod-shaped frame members into a rectangular frame shape and disposed at an underfloor inspection port of the clean room to support the lid of the underfloor inspection port. The method includes: a first step of bending a strip-shaped metal plate to form a lower support portion that supports the outer peripheral portion of the lid from below and a side support portion that supports the outer peripheral portion of the lid from the side; a second step of disposing a packing over the longitudinal direction of the strip-shaped metal plate at least on the lower support portion of the strip-shaped metal plate after the first step; a third step of cutting the strip-shaped metal plate and the packing into the size of the rod-shaped frame member after the second step; and a fourth step of welding the ends of the four rod-shaped frame members to each other and assembling them into a rectangular frame shape.

[0007] In such a manufacturing method, since the packing is joined to the strip-shaped metal plate before cutting and assembling it into a rectangular frame shape, the packing can be mechanically disposed inline using an existing bonding machine or the like. Therefore, according to the present invention, the operation of disposing the packing can be made more efficient than the conventional method. Also, the quality is more stable and the defective rate is reduced compared to the conventional method of manually bonding the packing. Note that the joining of the strip-shaped metal plate and the packing is not limited to the use of an adhesive, and bonding with an adhesive or welding may also be acceptable.

[0008] In the present invention, it is proposed that in the fourth step, the ends of the rod-shaped frame members are laser co-welded. In the present invention, since the rod-shaped frame members are welded to each other with the packing joined, if the joined portion of the packing is heated, the packing may peel, deform, or deteriorate. On the other hand, in laser co-welding, since the amount of energy applied to the welded portion is less than that of other welding methods, the amount of heat transmitted to the joined portion of the packing can be minimized.

[0009] In the present invention, in the second step, it is proposed that a molten packing material is poured onto the lower support portion of the strip-shaped metal plate and cured to dispose the packing. According to such a method, the packing can be disposed more efficiently than disposing a formed string-shaped packing on the strip-shaped metal plate, and the strip-shaped metal plate and the packing can be firmly joined. Further, it is desirable that the bending process applied to the strip-shaped metal plate in the first step is roll forming. If it is roll forming, the strip-shaped metal plate can be efficiently formed into a required shape.

[0010] In the present invention, the strip-shaped metal plate has a length equal to or greater than the outer peripheral length of the inspection port receiving frame for the clean room, and in the third step, it is proposed to obtain at least the four rod-shaped frame members from one strip-shaped metal plate and the packing. According to such a method, in the second step, it becomes possible to join the packing to all the rod-shaped frame members constituting the inspection port receiving frame at once, so that the packing disposal work can be further streamlined.

[0011] In the present invention, in the fourth step, it is proposed that the side support portions of the four rod-shaped frame members are welded to each other, and the lower support portions of the four rod-shaped frame members are not welded to each other. According to such a method, when the rod-shaped frame members are welded, it becomes more difficult for heat to be transferred to the packing joined to the lower support member.

Advantages of the Invention

[0012] As described above, according to the present invention, compared with the conventional manufacturing method, the disposal of the packing becomes easier, and the defective rate can also be reduced.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiment for Carrying Out the Invention

[0014] The inspection port receiving frame 1 for a clean room according to this embodiment (hereinafter, also simply referred to as "inspection port receiving frame") is a square frame as shown in FIGS. 1 and 2. Such an inspection port receiving frame 1 is disposed on the outer peripheral edge of an inspection port opening on the floor surface of a clean room and supports a square plate-shaped lid C that closes the inspection port.

[0015] As shown in FIG. 3, the inspection port receiving frame 1 is formed by joining four rod-shaped frame members 2 of the same configuration at their ends to form a square shape. As shown in FIG. 4, the rod-shaped frame member 2 includes a rod-shaped metal piece 3 and a packing 4.

[0016] The rod-shaped metal piece 3 constitutes the skeleton of the rod-shaped frame member 2 and is formed of a strip-shaped metal plate bent into a substantially L-shaped cross section. Specifically, the rod-shaped metal piece 3 uses the substantially L-shaped cross-sectional horizontal bar portion as a lower support portion 8 that supports the outer peripheral portion of the lid C from below, and the substantially L-shaped cross-sectional vertical bar portion as a side support portion 9 that supports the outer peripheral portion of the lid C from the side. As the material of the rod-shaped metal piece 3, stainless steel or aluminum is preferably used.

[0017] The packing 4 is a hollow string-shaped body made of a thermoplastic elastomer such as rubber or urethane, and is integrally joined to the upper surface of the lower support portion 8 over the entire length of the rod-shaped metal piece 3. When the lid C is attached to the inspection port receiving frame 1, the packing 4 is in close contact with the bottom surface of the outer peripheral portion of the lid C, thereby preventing the lid C from rattling and improving the sealing degree of the inspection port. As the packing 4, those disposed in conventional inspection port receiving frames can be widely used.

[0018] Hereinafter, the manufacturing method of the above-described inspection port receiving frame 1 will be described. The manufacturing method of the inspection port receiving frame 1 includes a first step of forming a strip-shaped metal plate 6 into a substantially L-shaped cross-section, a second step of disposing a packing 4 on the strip-shaped metal plate 6, a third step of cutting the strip-shaped metal plate 6 and the packing 4 to the size of the rod-shaped frame member 2, and a fourth step of assembling the rod-shaped frame members 2 into a square frame shape, which are executed in order. Hereinafter, each step will be described in detail.

[0019] In the first step, as shown in FIGS. 5(A)→5(B), the strip-shaped metal plate 6 serving as the material of the rod-shaped metal piece 3 is roll-formed into a substantially L-shaped cross-section to form the lower support portion 8 and the side support portion 9. The strip-shaped metal plate 6 is one having a length equal to or longer than the outer peripheral length of the inspection port receiving frame 1. With such a length, four rod-shaped metal pieces 3 constituting the inspection port receiving frame 1 can be obtained from one strip-shaped metal plate 6.

[0020] In the second step, as shown in FIGS. 5(B)→5(C), the packing 4 is disposed on the upper surface of the lower support portion 8 over the entire length of the strip-shaped metal plate 6. Specifically, an adhesive is applied to the upper surface of the lower support portion 8, and a molten packing material (thermoplastic resin) is poured thereon and cured, whereby the packing 4 is disposed integrally with the strip-shaped metal plate 6. Such a step can be performed using existing processing machines.

[0021] In the third step, as shown in FIGS. 5(C)→5(D), the strip-shaped metal plate 6 and the packing 4 are cut to the size of the rod-shaped frame member 2 to obtain four rod-shaped frame members 2 constituting the inspection port receiving frame 1. The ends of each rod-shaped frame member 2 are cut at an angle of 45° with respect to the longitudinal direction so that the respective ends can be joined at right angles to each other (see FIG. 1). The cutting method is not particularly limited, but it can be easily cut using a metal saw or a chip saw.

[0022] In the fourth step, as shown in Fig. 1, four rod-shaped frame members 2 are assembled into a square frame shape by welding the respective ends at right angles. Specifically, the side support portions 9 at the ends of the rod-shaped metal pieces 3 are welded together. Since the packing 4 is joined to the lower support portion 8, welding the side support portions 9 makes it more difficult for heat to transfer to the joint portion of the packing 4 than welding the lower support portion 8. Also, during welding, the side support portions are co-welded by laser welding from the outside. Co-welding using a laser can minimize the amount of heat transferred to the joint portion of the packing 4 because the amount of energy applied to the welded portion is less compared to other welding methods. Since the packing 4 and the adhesive for bonding the packing 4 are easily affected by heat, such a method can prevent the packing 4 and the adhesive from deforming and deteriorating due to the heat during welding and the packing 4 from peeling off from the end portion.

[0023] In the above manufacturing method, since the packing 4 is disposed on the strip-shaped metal plate 6 before assembling it into a square frame shape, the packing 4 can be mechanically disposed in-line using existing processing machines. Therefore, according to such a manufacturing method, the work of disposing the packing 4 can be made more efficient than the conventional method. Also, compared to the conventional method of manually bonding the packing 4, the bonding strength between the rod-shaped metal piece 3 and the packing 4 can be stabilized, thus reducing the defect rate.

[0024] In particular, in the above manufacturing method, the length of the strip-shaped metal plate 6 is made longer than the outer peripheral length of the inspection port receiving frame 1, and four rod-shaped metal pieces 3 are produced from one strip-shaped metal plate 6. According to such a configuration, in the second step, the packing 4 can be disposed on all the rod-shaped metal pieces 3 constituting the inspection port receiving frame 1 at once, so that the work of disposing the packing 4 can be made even more efficient.

[0025] Also, in the above manufacturing method, the packing 4 is disposed by pouring a molten packing material (thermoplastic resin) onto the lower support portion 8 of the strip-shaped metal plate 6 and curing it. Therefore, there is an advantage that the packing 4 can be disposed more efficiently than bonding a formed string-shaped packing to the strip-shaped metal plate 6, and the strip-shaped metal plate 6 and the packing 4 can be firmly joined.

[0026] In addition, in this embodiment, after the packing 4 is adhered to the rod-shaped metal piece 3, the rod-shaped frame members 2 are welded to each other. However, as described above, in the fourth step, the side support portions 9 of the rod-shaped frame members 2 are welded together by co-welding using a laser, and the lower support portions 8 are not welded to each other. Therefore, there is an advantage that heat during welding hardly transfers to the packing 4 or the adhesive.

[0027] Although the embodiments of the present invention have been described above, the present invention is not limited to the forms of the above embodiments, and various modifications can be made without departing from the gist of the present invention. For example, the inspection port receiving frame 1 according to the present invention is not limited to a square shape, and may be a rectangular shape. Further, in the above-described manufacturing method, four rod-shaped frame members 2 are manufactured from one strip-shaped metal plate 6. However, one to three rod-shaped frame members 2 may be manufactured from one strip-shaped metal plate 6, or five or more rod-shaped frame members 2 may be manufactured. Further, although it is more suitable for mass production that the four rod-shaped frame members 2 have the same configuration, they do not necessarily have to have the same configuration.

[0028] In addition, in the first step according to the present invention, it is desirable to bend the strip-shaped metal plate 6 by roll forming as in the above embodiment. However, the strip-shaped metal plate 6 may be processed by bending other than roll forming (such as bending). Further, in the second step according to the above embodiment, the molten packing material is poured onto the upper surface of the lower support portion 8 to integrally join the packing 4 and the strip-shaped metal plate 6. However, a formed string-shaped packing may be joined to the upper surface of the lower support portion 8 inline. Further, the joining of the rod-shaped metal piece 3 and the packing 4 may be by joining using an adhesive or by welding. Further, in the fourth step according to the above embodiment, only the side support portions 9 of the rod-shaped metal piece 3 are co-welded by a laser. However, if there is no risk of the packing 4, the adhesive, etc. being deteriorated by heat, the lower support portions 8 may be welded to each other, or a welding method other than laser welding or co-welding may be adopted.

Explanation of Reference Numerals

[0029] 1 Inspection port receiving frame for clean room 2 Rod-shaped frame member 3 Rod-shaped metal piece 4 Packing 6 Strip-shaped metal plate 8 Lower support part 9 Lateral support part C Cover

Claims

1. A manufacturing method of an inspection port receiving frame for a clean room, which is formed by assembling four rod-shaped frame members in a rectangular frame shape and is disposed at an underfloor inspection port of the clean room to support a lid of the underfloor inspection port, comprising: a first step of bending a strip-shaped metal plate to form a lower support portion that supports the outer peripheral portion of the lid from below and a side support portion that supports the outer peripheral portion of the lid from the side; a second step of disposing a packing over at least the lower support portion of the strip-shaped metal plate in the longitudinal direction of the strip-shaped metal plate after the first step; a third step of cutting the strip-shaped metal plate and the packing to the size of the rod-shaped frame member after the second step; a fourth step of welding the ends of the four rod-shaped frame members to each other to assemble them in a rectangular frame shape A manufacturing method of an inspection port receiving frame for a clean room, characterized by comprising the above steps.

2. The manufacturing method of the inspection port receiving frame for a clean room according to claim 1, wherein in the fourth step, the ends of the rod-shaped frame members are laser co-welded to each other.

3. The manufacturing method of the inspection port receiving frame for a clean room according to claim 1, wherein in the second step, the packing is disposed by pouring a molten packing material onto the lower support portion of the strip-shaped metal plate and curing it.

4. The strip-shaped metal plate has a length equal to or longer than the outer peripheral length of the inspection port receiving frame for the clean room, The manufacturing method of the inspection port receiving frame for a clean room according to any one of claims 1 to 3, wherein in the third step, at least the four rod-shaped frame members are obtained from one strip-shaped metal plate and the packing.

5. The manufacturing method of the inspection port receiving frame for a clean room according to any one of claims 1 to 3, wherein in the fourth step, the side support portions of the four rod-shaped frame members are welded to each other, and the lower support portions of the four rod-shaped frame members are not welded to each other.

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