JP7380046B2 - Paint applicator and paint application method - Google Patents

Description

The present invention relates to a paint applicator and a paint application method used when applying paint to an internally threaded portion formed on a member such as a pipe joint.

BACKGROUND ART As a paint applicator for applying paint to a female threaded portion of a pipe joint, one described in Patent Document 1 is known. As shown in FIG. 10, this paint applicator 11 has a thin cylindrical main body 12 that is inserted in the axial direction into the inner diameter side of a pipe joint that is fixed so that the axis is horizontal. 12 is inserted along the female threaded portion of the joint so that the tip thereof lightly contacts the innermost female threaded portion. The paint applicator 11 applies paint to the female thread by rotating around the axis of the pipe joint while discharging the paint from a discharge port 13 formed in a direction perpendicular to the axis into the gap between the female thread and the main body 12. . According to this paint applicator, the main body 12 can apply paint over the entire circumference of the threaded portion without coming into contact with the female threaded portion except for the innermost portion of the threaded portion. However, in the paint applicator 11 described in Patent Document 1, since the paint is applied to a pipe joint whose axis is fixed in the horizontal direction, the thickness of the applied paint is in the circumferential direction of the female thread. There is a risk of variation. Therefore, the applicant fixes the pipe joint so that its axis is vertical, and uses a cylindrical paint applicator that has approximately the same diameter as the internal diameter of the female thread and has a smooth outer circumferential surface. We tried applying paint by inserting it into the threaded part and rotating it. As a result, the variation in paint thickness in the circumferential direction of the female threaded portion was certainly improved.

Japanese Patent Application Publication No. 8-168711

However, if you try to apply paint to a female threaded part whose axis is vertical, using a cylindrical paint applicator with a smooth outer surface, you will not be able to apply enough paint to the entire female threaded part. In some cases, the thickness of the paint was uneven on the female thread, and the tip of the thread was exposed.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a paint application method that can reliably apply paint to the entire female threaded portion regardless of the direction of the axis of the female threaded portion. It is to provide the ingredients. Another object of the present invention is to provide a paint application method that can reliably apply paint to an internally threaded portion formed in a hole whose axis is vertical.

The paint applicator of the present invention is a paint applicator that includes a cylindrical main body that is inserted into a hole in which a female thread is formed, and that applies paint supplied onto the outer peripheral surface of the main body to the female thread. The main body has a paint retaining portion on the outer circumferential surface of the main body at a position facing the female threaded portion when inserted into the hole, in which the paint is retained.

In the paint applicator of the present invention, the paint holding portion can be provided by forming at least one paint holding groove on the outer periphery of the main body along the direction of the axis of the main body.

Further, in the paint applicator of the present invention, the paint holding portion may be provided by forming at least one or more recesses on the outer peripheral surface of the main body of the paint applicator of the present invention.

Further, in the paint applicator of the present invention, the main body may be a cylindrical body having a predetermined thickness and having a hollow inner diameter side.

The paint application method of the present invention is a method for applying paint to an internal thread formed in a hole whose axis is vertical, and the paint applicator is placed inside the hole so that the axis of the paint applicator is vertical. an insertion process in which the paint applicator is inserted, a coating process in which the paint applicator is rotated around its axis and the paint on the outer circumferential surface of the paint applicator is applied to the female thread, and after the coating process, the paint applicator is removed from the hole. The paint applicator used in this coating method is the aforementioned paint applicator of the present invention.

In the paint application method of the present invention, the position of the paint applicator in the coating process is such that the axis of the paint applicator is offset in the radial direction with respect to the axis of the hole; It is preferable to rotate around the axis of the hole and around the axis of the hole.

The paint application method of the present invention includes a centering step of moving the paint applicator and/or the hole so that the axis of the paint applicator and the axis of the object to be coated are on the same line before the sampling step. is preferred.

According to the paint applicator of the present invention, paint can be reliably applied to the entire female threaded portion regardless of the direction of the axis of the female threaded portion. Further, according to the paint applicator of the present invention, the paint can be reliably applied to the internal threaded portion formed in the hole whose axis is vertical.

FIG. 1 is a perspective view showing a paint applicator according to a first embodiment of the present invention. FIG. 2 is a front view of the paint applicator of FIG. 1; FIG. 3 is a sectional view taken along line AA in FIG. 2; FIG. 3 is a cross-sectional view showing a state before the paint applicator is inserted into the object to be coated. FIG. 3 is a cross-sectional view showing a state in which a paint applicator is inserted into an object to be coated. FIG. 3 is a sectional view showing a paint applicator according to a second embodiment of the present invention. FIG. 3 is a cross-sectional view showing an example of the positional relationship between a hole and a paint applicator. FIG. 7 is a sectional view showing another example of the positional relationship between the hole and the paint applicator. FIG. 3 is a sectional view showing the operation of the paint applicator in the centering process. 1 is a sectional view showing a prior art paint applicator; FIG.

(First embodiment)
Hereinafter, the paint applicator of the present invention will be explained with reference to the drawings. FIG. 1 is a perspective view of a paint applicator according to a first embodiment of the present invention, FIG. 2 is a front view of a paint applicator according to a first embodiment of the present invention, and FIG. 3 shows a cross section taken along line AA in FIG. FIG. FIG. 4 is a cross-sectional view showing the state before the paint applicator is inserted into the object to be coated, and FIG. 5 is a cross-sectional view showing the state after the paint applicator is inserted into the object to be coated.

As shown in FIG. 1, the paint applicator 1 includes a cylindrical main body 2. As shown in FIG. As shown in FIGS. 4 and 5, the paint applicator 1 has a main body 2 inserted into a hole H in which a female thread F is formed in an object 10 to be coated, such as a pipe joint. The paint C supplied on the outer peripheral surface is applied to the female threaded portion F. The supplied paint C is a liquid paint such as a sealant, adhesive, or lubricant, and is selected depending on the application. The means for supplying the paint C onto the outer peripheral surface of the main body 2 is not particularly limited. For example, the paint C may be provided on the paint applicator itself with a paint supply flow path leading to the outer peripheral surface of the main body, and may be supplied onto the outer peripheral surface of the main body via the flow path, or the paint C may be supplied onto the outer peripheral surface of the main body with a brush or the like. It may be supplied on the outer peripheral surface of.

The main body 2 has a paint holding portion 21 on its outer peripheral surface in which the supplied paint C is held. As shown in FIG. 5, the paint holding portion 21 is provided at a position facing the female threaded portion F on the outer peripheral surface when the main body 2 is inserted into the hole H of the object to be coated 10. By providing the paint holding portion 21 in this portion, the paint C can be reliably applied to the female thread portion during the coating process described later.

In the paint applicator 1 of FIG. 1, as shown in FIGS. 1 to 3, the paint holding portion 21 has eight paint holding grooves 211 formed on the outer periphery of the main body 2 along the direction of the axis Z1 of the paint applicator 1. It is established by being The paint holding groove 211 has a width such that the paint C that has entered the paint holding groove 211 can remain in the paint holding groove 211 due to the action of surface tension when the axis Z1 of the paint applicator 1 is in the vertical direction. and designed to depth. In the paint applicator of the present invention, the number of paint holding grooves 211 is not limited to eight. In the paint applicator of the present invention, the number of paint holding grooves 211 may be at least one or more, and may be determined as appropriate depending on the required holding performance.

In addition to the paint holding groove 211, the paint holding portion 21 can also be provided by forming at least one or more depressions on the outer peripheral surface of the main body 2. The depressions can be shaped like dimples formed on the surface of a golf ball, for example.

(Second embodiment)
In the first embodiment, a paint applicator for applying paint C to a coating object 10 having a hole H having only a female threaded portion F formed on the inner surface has been described. However, for example, as in the pipe joint shown in FIG. 6, a female threaded portion F is formed on the inner surface of the hole H, and a core 3 is further provided at a position closer to the axis Z1 than the female threaded portion F. In the object 10 to be coated, the paint may be applied to the female threaded portion F in some cases. In such a case, the paint can be applied using a hollow paint applicator 1' shown in FIG. The paint applicator 1' is the same as the paint applicator 1 shown in FIG. 1 except that the main body is hollow. Therefore, the same parts are given the same reference numerals and the description thereof will be omitted.

In the paint applicator 1', the main body 2' is a cylindrical body that is hollow on the inner diameter side and has a predetermined thickness. In the main body 2', the inner diameter of the cylindrical body is larger than the outer diameter of the core 3, and the outer diameter of the cylindrical body is smaller than the inner diameter of the female threaded portion F. The main body 2' is inserted into an annular space formed between the core 3 and the female thread F in the object to be coated 10. In the present invention, the "predetermined thickness" of the cylindrical body refers to a thickness that allows the cylindrical body to be inserted into the annular space between the core 3 and the female threaded portion F. can be appropriately designed depending on the outer diameter of the core 3 and the inner diameter of the female threaded portion F.

Next, the paint application method of the present invention will be explained. The paint application method of the present invention is a paint application method in which paint is applied to the female threaded portion F of the object 10 to be coated. The object to be coated 10 is, for example, a pipe joint, and has an internally threaded portion F formed in a hole H whose axis Z2 is in the vertical direction. The paint applicator used in the paint application method of the present invention is the aforementioned paint applicator of the present invention. Here, a method for applying paint to the object to be applied 10 shown in FIG. 4 will be described.

The paint application method of the present invention includes an insertion step, an application step, and a removal step. The details of each step will be explained below.

(insertion process)
The insertion step is a step of inserting the paint applicator 1 into the object 10 to be coated. The coating object 10 shown in FIG. 4 has a hole H in which a female thread F is formed at both ends in the axial direction, and is fixed by, for example, a chucking device (not shown) so that the direction of the axis Z2 is vertical. ing. As shown in FIG. 5, in the insertion step, the paint applicator 1 is inserted into the hole H of the object 10 to be coated. The paint applicator 1 is inserted so that the outer circumferential surface of the paint applicator 1 is along the female thread F and the axis Z1 is parallel to the axis Z2 of the hole H. In the case of the embodiment illustrated in FIGS. 4 and 5, the axis Z2 of the hole H and the axis Z1 of the paint applicator 1 coincide.

Further, in the insertion process, the paint applicator 1 is inserted to a position in the axial direction where the paint holding portion 21 faces the entire female threaded portion in the axial direction. Then, since the paint holding portion 21 is provided at a position facing the female threaded portion when inserted into the hole, the paint holding portion 21 faces the entire female threaded portion in the axial direction. As a result, the coating material C is reliably applied to the entire female threaded portion in the axial direction in the coating process described later.

(Coating process)
The coating process is a process of applying paint C to the female threaded portion F. More specifically, in the application step, the paint applicator 1 inserted into the hole H in the insertion step is rotated around the axis, and the paint is applied onto the outer peripheral surface of the paint applicator held in the paint holding part 21. This is the process of applying it to the threaded part F. The paint C applied in the coating process may be supplied to the paint holding part 21 in the coating process, or may be supplied to the paint holding part 21 in advance at the stage of the insertion process.

FIG. 7 is a cross-sectional view schematically showing a state in which the paint C is supplied to the paint applicator 1. As shown in FIG. When the paint C is supplied to the paint applicator by the paint supply means, it enters the paint holding groove 211. The paint applicator 1 has a paint holding groove 211 formed therein, and has a larger surface area than a case without a paint holding groove. Since the ability to hold the paint increases as the surface area increases, the paint applicator 1 can hold the paint C more firmly than when there is no paint holding groove. Therefore, according to the paint applicator 1, the paint C can be reliably applied to the female threaded portion F even when the axis Z1 is in the vertical direction. Furthermore, as shown in FIG. 7, the paint C that has entered the paint holding groove 211 is held in a state in which its surface bulges out more than the surface of the main body 2 due to the effect of surface tension. It is thought that this also contributes to ensuring that the paint C contacts the female threaded portion F.

(Sampling process)
The extraction step is a step in which the paint applicator 1 is extracted from the hole H after the paint C is applied to the female threaded portion F in the application step. Since the paint applicator 1 has a high ability to hold paint, it holds the paint C in the paint application groove 211 in a state similar to that shown in FIG. 7 immediately after finishing the coating process, and the surface of the paint C and the female thread F are are in contact. When the paint applicator 1 is pulled out from the hole H in this state, the paint C is applied to the female threaded portion F even when the paint applicator 1 is pulled out. In this way, according to the paint applicator 1, the coating is supplemented even during the drawing process, so that more reliable coating can be achieved.

After the extraction step, the object to be coated 10 is removed and dried to complete the coating.

Further, as shown in FIG. 8, the position of the paint applicator 1 during the coating process can be such that the axis Z1 of the paint applicator 1 is offset in the radial direction with respect to the axis Z2 of the hole H. If the paint applicator 1 is simply offset with respect to the hole H, the distance between the female threaded portion F and the outer peripheral surface of the paint applicator 1 will be uneven, so the paint C will be applied uniformly to the entire circumference of the female threaded portion F. cannot be applied. Therefore, in this case, in the coating process, the paint applicator 1 is rotated around the axis Z1 of the paint applicator 1 in the direction of arrow R1, and around the axis Z2 of the hole H in the direction of arrow R2. By doing so, the paint C can be applied uniformly over the entire circumference of the female threaded portion F. According to this method, the amount of coating applied to the female threaded portion F can be easily adjusted by adjusting the offset amount. Furthermore, since it is not necessary to match the outer diameter of the paint applicator 1 to the inner diameter of the hole H, one paint applicator 1 can be used for a plurality of holes H having different inner diameters.

Furthermore, after finishing the coating process and before pulling out the paint applicator 1 from the hole H, as shown in FIG. It is preferable to provide a centering step in which the paint applicator 1 is moved in the direction of the arrow r so that the paint applicator 1 is moved in the direction of the arrow r. If the paint applicator 1 is pulled out in the state shown in FIG. 8, there is a risk that the paint C may be partially dragged and the thickness of the applied paint becomes uneven, but this can be prevented by providing a centering process. Can be done. If the difference in size between the outer diameter of the paint applicator 1 and the inner diameter of the hole H is large, the centering process brings the outer circumferential surface of the paint applicator 1 and the female threaded portion F out of contact with each other. Therefore, the paint C applied to the female threaded portion F is not affected by the drawing process. Furthermore, if the difference in dimension between the outer diameter of the paint applicator 1 and the inner diameter of the hole H is small, the paint C is evenly interposed over the entire circumference between the paint applicator 1 and the female thread F by the centering process. be done. Therefore, even in the drawing process, the state of the paint C is uniform over the entire circumference, and there is no difference in the state of the applied paint. As described above, according to this method, in any of the above cases, unevenness in the thickness of the paint C during the drawing process can be prevented, and uniform paint C can be applied over the entire circumference of the female threaded portion F. Can be applied. In the above description, the form in which the paint applicator 1 is moved in the centering process has been described, but the object to be coated 10 may be moved, or both the applicator 1 and the object to be applied 10 may be moved. .

Although the embodiments of the invention have been described above using examples, they can be modified without departing from the gist of the invention. Further, the present invention includes other forms without departing from the gist of the invention. For example, in the present invention, the paint retaining portion may have any shape as long as it is a recess that recedes from the outer peripheral surface of the main body toward the axis and retains the paint. Moreover, the "cylindrical shape" in the present invention is not limited to a completely cylindrical body having the same cross section throughout the axial direction. In the present invention, the term "cylindrical body" includes a body shaped like a partially cut-off conical column.

1, 1': Paint applicator
2, 2': Main body 21: Paint holding part
211: Paint holding groove 10, 10': Application target 3: Core H: Hole F: Female thread C: Paint Z1: Axis of paint applicator Z2: Axis of hole

Claims (2)

A method of applying paint to an object to be applied having an internal thread formed in a hole whose axis is vertical, the method comprising:
an insertion step of inserting the paint applicator into the hole so that the axis of the paint applicator is in the vertical direction;
a coating step of rotating the paint applicator around an axis and applying the paint on the outer peripheral surface of the paint applicator to the female threaded portion;
after the coating step, the paint applicator is pulled out from the hole;
The paint applicator is
The main body has a cylindrical shape that is inserted into a hole in which a female thread is formed, and when the main body is inserted into the hole, the paint is applied to a position facing the female thread on the outer peripheral surface of the main body. A paint applicator that has a paint holding part that stays and applies the paint supplied on the outer peripheral surface of the main body to the female thread part,
The position of the paint applicator in the coating process is
the axis of the paint applicator is radially offset from the axis of the hole;
In the coating step,
A paint application method in which the paint applicator is rotated around the axis of the paint applicator and around the axis of the hole. Before the sampling step,
The paint application method according to claim 1, further comprising a centering step of moving the paint applicator and/or the object to be coated so that the axis of the paint applicator and the axis of the hole are on the same line.

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