Method for painting support member

Abstract

To provide a method for painting a support member, which can improve the painting quality of the support member.SOLUTION: The method for painting a support member 100 having a cylindrical portion 101 and a cap portion 102 fixed to the end of the cylindrical portion 101 includes a pretreatment step of performing pretreatment before painting including a water washing treatment, an air blowing step of blowing air onto the cap portion 102 after the pretreatment step, and a painting step of painting the support member 100 after the air blowing step. In the air blowing step, air is blown onto the cap portion 102 while the support member 100 is transported in a transport direction along a horizontal plane in an orientation such that the support member extends vertically and the cap portion 102 faces upward.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a method for painting a support member.

Background Art

[0002] Conventionally, as a protective fence such as a guardrail provided on a road, one provided with a retroreflective coating film has been proposed (see, for example, Patent Document 1). In the protective fence described in Patent Document 1, by providing a retroreflective coating film, both the landscape and visibility are achieved.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In order to provide a predetermined function on the surface of the protective fence as described in Patent Document 1, an appropriate painting process is required. Such a protective fence generally includes a support member fixed to the road surface. This support member has a metal cylindrical portion extending along the vertical direction and a metal cap provided so as to close the opening of the cylindrical portion from above, and the cylindrical portion and the cap are fixed by welding or the like.

[0005] When painting such a support member, pretreatment is required to make the surface state suitable for painting, such as removing dirt generated by welding or the like. When such pretreatment includes water washing treatment, although it is necessary to remove moisture before painting, depending on the shape of the support member and the direction of conveyance, there may be a portion where moisture easily remains, and there is a risk that the quality of the painting cannot be ensured.

[0006] The present invention has been made in view of the above problems, and an object thereof is to provide a method for painting a support member that can improve the painting quality of the support member.

Means for Solving the Problems

[0007] In order to achieve the above object, a painting method for a support member according to the present invention is a painting method for a support member having a cylindrical portion and a cap portion fixed to an end of the cylindrical portion, including a pretreatment step of performing pretreatment of painting including a water washing treatment, a blowing step of blowing air against the cap portion after the pretreatment step, and a painting step of painting the support member after the blowing step. In the blowing step, while transporting the support member in a transport direction along a horizontal plane in a posture where the support member extends along a vertical direction and the cap portion faces upward, air is blown against the cap portion.

[0008] In the painting method for a support member according to an aspect of the present invention, in the blowing step, air is blown against the cap portion from both sides in a direction orthogonal to the transport direction in a horizontal plane.

[0009] In the painting method for a support member according to an aspect of the present invention, in the blowing step, the blowing direction is a direction inclined toward the downstream side of the transport direction with respect to the orthogonal direction.

[0010] In the painting method for a support member according to an aspect of the present invention, in the blowing step, the blowing position on one side in the orthogonal direction is upstream of the transport direction from the blowing position on the other side.

[0011] In the painting method for a support member according to an aspect of the present invention, between the pretreatment step and the blowing step, a preliminary blowing step of blowing air against a holding portion that holds the support member upstream of the transport direction from the blowing position against the cap portion is further included.

Advantages of the Invention

[0012] According to the painting method for a support member of the present invention, the painting quality can be improved.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0014] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a side view showing a support member 100 to be painted by a painting method of a support member according to an embodiment of the present invention, FIG. 2 is a side view showing an outline of a painting apparatus 1 used in a painting method of a support member according to an embodiment of the present invention, and FIG. 3 is a plan view showing a main part of the painting apparatus 1.

[0015] As shown in FIGS. 1 to 3, a painting method of a support member according to an embodiment of the present invention is a painting method of a support member 100 having a cylindrical portion 101 and a cap portion 102 fixed to an end of the cylindrical portion 101, including a pretreatment step of performing a pretreatment of painting including a water washing treatment, a blowing step of blowing air to the cap portion 102 after the pretreatment step, and a painting step of painting the support member 100 after the blowing step. In the blowing step, while conveying the support member 100 in a conveying direction along a horizontal plane in a posture extending along the vertical direction and with the cap portion 102 facing upward, air is blown to the cap portion 102. Hereinafter, the painting method of the support member will be specifically described.

[0016] The support member 100 constitutes, for example, a guardrail. As shown in FIG. 1, it has a cylindrical tubular portion 101 and a cap portion 102 fixed to one end of the tubular portion 101. The tubular portion 101 is fixed to the road surface so as to extend along the vertical direction, and the cap portion 102 is provided at the upper end. Incidentally, openings or the like for attaching horizontal members such as beams and wires constituting the guardrail may be appropriately formed on the side surface of the tubular portion 101. Also, the tubular portion only needs to be tubular and is not limited to a cylindrical shape, and may be other shapes such as a polygonal tubular shape.

[0017] The cap portion 102 integrally has a cap body 103 formed in a circular shape in plan view to close the opening of the tubular portion 101 and a tubular connection portion 104 continuous with the outer peripheral edge of the cap body 103. The cap body 103 is formed in a curved plate shape convex toward the side away from the tubular portion 101 (i.e., the upper side when installed on the road surface). At this time, a portion extending along a horizontal plane or a portion convex downward may be formed in a part of the cap body 103, and water droplets tend to remain on these portions in the same posture as when installed on the road surface.

[0018] The tubular connection portion 104 is formed in a cylindrical shape and is disposed outside the tubular portion 101. The cap portion 102 is mainly fixed by welding the tubular connection portion 104 to the end of the tubular portion 101. Incidentally, the fixing method of the cap portion 102 to the tubular portion 101 is not limited to welding, and fixing methods such as caulking and bolts may be adopted.

[0019] Next, the details of the coating device 1 used in the coating method of the support member 100 according to the embodiment of the present invention will be described. As shown in FIG. 2, the coating device 1 includes a conveying portion 2, a pretreatment portion 3, a blowing portion 4, and a coating portion 5, and performs powder coating.

[0020] The conveying unit 2 conveys the columnar members 100 in the conveying direction along the horizontal plane. At this time, the columnar members 100 are in a posture where the whole extends along the vertical direction and the cap portion 102 faces upward. For the sake of convenience in FIG. 2, it is assumed that the conveying directions in each of the pretreatment unit 3, the air blowing unit 4, and the painting unit 5 are the same direction. However, these directions may be appropriately set according to the layout in the factory and may intersect each other in the horizontal plane. Hereinafter, the vertical direction is defined as the Z direction, the conveying direction of the conveying unit 2 in the air blowing unit 4 is defined as the X direction, and the direction orthogonal to both the X direction and the Z direction is defined as the Y direction. In addition, the upstream side and the downstream side of the conveying direction in each of the pretreatment unit 3, the air blowing unit 4, and the painting unit 5 may be simply referred to as the "upstream side" and the "downstream side". In FIG. 2, the upstream side of the air blowing unit 4 is the left side and the downstream side is the right side.

[0021] The conveying unit 2 conveys a plurality of columnar members 100 so as to be arranged in the conveying direction, so that each of the plurality of columnar members 100 sequentially passes through the pretreatment unit 3, the air blowing unit 4, and the painting unit 5. The conveying unit 2 has a holding unit 21 that holds each columnar member 100. The holding unit 21 is formed in a hook shape that is locked to the opening formed in the cylindrical portion 101 of the columnar member 100 and holds the columnar member 100 so as to suspend it. The holding unit 21 integrally includes, in order from above, a vertical portion 211 that extends so as to pass through the central axis of the cylindrical portion 101, an inclined portion 212 that extends obliquely with respect to the Z direction from the lower end portion of the vertical portion 211, and a hook portion 213 that is continuous with the lower end portion of the inclined portion 212 and extends toward the cylindrical portion 101.

[0022] The pretreatment unit 3 performs pretreatment on the columnar member 100 according to the fixing method of the cylindrical portion 101 and the cap portion 102 and the type of painting performed in the painting unit 5. Specifically, in the pretreatment unit 3, a cleaning process for removing dirt generated when welding the cylindrical portion 101 and the cap portion 102 and oil films generated in processes other than welding, a plating process for improving the adhesive strength of the paint, and a water washing process as the final process of these are performed. Thus, in the pretreatment unit 3, pretreatment of painting including the water washing process is performed, that is, the pretreatment process is performed.

[0023] The air blowing unit 4 removes the water droplets remaining on the cap body 103 of the cap portion 102 by blowing air particularly to the cap portion 102 among the support members 100. In the present embodiment, it is assumed that the air blowing unit 4 is connected to a gas supply source such as a cylinder in which compressed air or other gas is stored and blows these gases, but the air blowing unit may simply generate an air flow by a fan or the like and blow air. Thus, the air blowing process is carried out in the air blowing unit 4.

[0024] The painting unit 5 dries the support member 100, sprays paint on the support member 100, and then performs a baking process on the paint. Note that the type of painting carried out in the painting unit is not limited to powder painting, and appropriate processes according to the type of painting may be carried out. Thus, the painting process is carried out in the painting unit 5.

[0025] As described above, the support member 100 conveyed by the conveying unit 2 in the painting apparatus 1 passes through the pretreatment unit 3, the air blowing unit 4, and the painting unit 5 in this order and each process is performed, whereby the support member 100 is painted. That is, the painting method of the support member of the present embodiment includes a pretreatment process, an air blowing process, and a painting process.

[0026] Here, the air blowing unit 4 will be described in more detail. As shown in FIG. 3, the air blowing unit 4 includes a first air blowing unit 41 and a second air blowing unit 42 that blow air to the cap portion 102, and a preliminary air blowing unit 43 that blows air to the holding portion 21. These air blowing units 41 to 43 may be connected to a common cylinder or may be connected to independent cylinders.

[0027] The first air blowing unit 41 and the second air blowing unit 42 are arranged so as to sandwich the support member 100 in the Y direction, and are configured to blow air to the cap portion 102 from both sides in the direction (Y direction) orthogonal to the conveying direction (X direction) in the horizontal plane.

[0028] The first air blowing unit 41 has a connection part connected to a gas supply source, a first blowing port 411, and a second blowing port 412. That is, the gas supplied from the connection part passes through the bifurcated flow paths and is blown out from each of the first blowing port 411 and the second blowing port 412. The first blowing port 411 is arranged upstream of the second blowing port 412 and is arranged near the support member 100 in the Y direction.

[0029] The second air blowing unit 42 has a connection part connected to a gas supply source and one blowing port 421. The blowing port 421 of the second air blowing unit 42 is arranged downstream of both the first blowing port 411 and the second blowing port 412 of the first air blowing unit 41. That is, the air blowing position on one side in the Y direction (the air blowing position of the first air blowing unit 41) is upstream of the air blowing position on the other side in the X direction (the air blowing position of the second air blowing unit 42).

[0030] Also, the first blowing port 411, the second blowing port 412, and the blowing port 421 each have a predetermined inclination angle θ1 to θ3 inclined downstream with respect to the Y direction. Thereby, the air blowing directions of the first air blowing unit 41 and the second air blowing unit 42 become directions inclined downstream with respect to the Y direction. Note that the inclination angles θ1 to θ3 may be equal to each other or different from each other.

[0031] As shown in FIG. 2, the preliminary air blowing unit 43 is arranged upstream of both the first air blowing unit 41 and the second air blowing unit 42. Thereby, a preliminary air blowing process of blowing air to the holding part 21 is carried out between the pretreatment process and the air blowing process (that is, upstream of the air blowing position with respect to the cap part 102 in the X direction). At this time, the air blowing direction of the preliminary air blowing unit 43 may be inclined downstream with respect to the Y direction in the same manner as the first air blowing unit 41 and the second air blowing unit 42, or may be along the Y direction. Also, the air blowing position of the preliminary air blowing unit 43 in the Z direction is preferably above the cap part 102.

[0032] Thus, according to the painting method of the support member according to the embodiment of the present invention, by blowing air against the cap portion 102 between the pretreatment step and the painting step, it is possible to easily remove the water droplets remaining on the cap portion 102 and improve the painting quality. By removing the water droplets by blowing air in this way, it is easier to improve the painting quality compared to the case of evaporating the water droplets at the initial stage of the painting process.

[0033] Further, by blowing air against the cap portion 102 from both sides in the Y direction, which is the direction orthogonal to the conveyance direction in the horizontal plane, it is possible to suppress the remaining of water droplets on one side in the Y direction.

[0034] Further, since the air blowing direction in the air blowing step is a direction inclined toward the downstream side with respect to the Y direction, the effective wind speed (the difference between the conveyance speed and the wind speed) does not become too large, and it is possible to suppress the remaining due to the scattering of water droplets.

[0035] Further, the air blowing position on one side in the Y direction is upstream of the air blowing position on the other side, and the air from both sides in the Y direction does not act on the cap portion simultaneously, so that the Y-direction components of the air from both directions do not cancel each other out. Thereby, for example, it is possible to suppress the remaining of water droplets at the central portion in the Y direction of the cap portion 102.

[0036] Further, by blowing air against the holding portion 21 between the pretreatment step and the air blowing step, it is possible to remove the moisture adhering to the holding portion 21. Thereby, after blowing air against the cap portion 102 to remove moisture, it is possible to suppress the dropping of water droplets from the holding portion 21 to the cap portion 102.

[0037] Furthermore, the present invention is not limited to the forms of the above-described embodiments, and includes other configurations and the like that can achieve the object of the present invention. Modifications and the like as described below are also included in the present invention. For example, in the above-described embodiment of the present invention, the blowing direction in the blowing step is inclined downward toward the downstream side with respect to the Y direction. However, the blowing direction may be appropriately set according to the wind speed during blowing, the conveying speed of the support member 100, etc., and may be along the Y direction or may be inclined toward the upstream side. That is, the blowing direction may be set so that the effective wind speed with respect to the cap portion 102 becomes an appropriate value.

[0038] Also, in the above-described embodiment of the present invention, the blowing position on one side in the Y direction is upstream of the blowing position on the other side. However, for example, when water droplets are less likely to remain on the cap portion due to differences in wind speed and blowing direction on both sides in the Y direction, the blowing positions on both sides in the Y direction may be arranged to face each other in the Y direction.

[0039] Also, in the above-described embodiment of the present invention, blowing is performed on the cap portion 102 from both sides in the Y direction. However, for example, when the upper surface of the cap portion is flat, and it is easy to remove water droplets even by blowing from one side, blowing may be performed from one side in the Y direction.

[0040] Also, in the above-described embodiment of the present invention, blowing is performed on the holding portion 21 between the pre-treatment step and the blowing step. However, for example, when the water repellency of the holding portion is high and moisture is less likely to remain, or when the water droplets falling from the holding portion have a shape or arrangement that makes it difficult to reach the cap portion, it may not be necessary to blow on the holding portion.

[0041] As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the coating method of the support member according to the above-described embodiments of the present invention, and includes all aspects included in the concept and scope of claims of the present invention. Also, each configuration may be appropriately and selectively combined so as to achieve at least some of the above-described problems and effects. For example, the shape, material, arrangement, size, etc. of each component in the above-described embodiment can be appropriately changed according to the specific usage mode of the present invention.

Description of Signs

[0042] 100... Support member, 101... Cylindrical part, 102... Cap part, 1... Coating device, 21... Holding part, 3... Pretreatment part, 4... Air blowing part, 5... Coating part

Claims

1. A method for painting a support member having a cylindrical portion and a cap portion fixed to an end of the cylindrical portion, comprising: a pretreatment step of performing pretreatment of painting including a water washing treatment; a blowing step of blowing air against the cap portion after the pretreatment step; a painting step of painting the support member after the blowing step, wherein in the blowing step, while the support member is being conveyed in a conveying direction along a horizontal plane in a posture in which the support member extends along a vertical direction and the cap portion faces upward, air is blown against the cap portion.

2. The method for painting a support member according to claim 1, wherein in the blowing step, air is blown against the cap portion from both sides in a direction orthogonal to the conveying direction in a horizontal plane.

3. The method for painting a support member according to claim 2, wherein the blowing direction in the blowing step is a direction inclined toward the downstream side in the conveying direction with respect to the orthogonal direction.

4. The method for painting a support member according to claim 2 or 3, wherein in the blowing step, the blowing position on one side in the orthogonal direction is upstream of the blowing position on the other side in the conveying direction.

5. The method for painting a support member according to any one of claims 1 to 3, further comprising a preliminary blowing step of blowing air against a holding portion that holds the support member upstream of the blowing position against the cap portion between the pretreatment step and the blowing step.

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