Masking tool

Abstract

To provide a masking tool that can improve workability in insertion work or pulling-out work to an opening part of a pipe member.SOLUTION: A masking tool 100 comprises a masking body 101 and an attachment / detachment tool 110. The masking body 101 has masking parts 102a and 102b which attachably and detachably fit to opening parts 11a and 11b of a pipe member 10 to cover inner peripheral surfaces thereof, and a turning force receiving part 106 whose cross section is formed in a non-circular shape so as to open in a direction in which the part fits to the pipe member 10. A cross section of the turning force receiving part 106 is formed in a rectangular shape. The attachment / detachment tool 110 has a first turning force applying part 111 and a second turning force applying part 112 which attachably and detachably fit to the turning force receiving part 106. An outline of the second turning force applying part 112 is formed to be larger than an outline of the first turning force applying part 111.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a masking tool for masking the inner peripheral surface of an opening of a pipe member. [Background technology]

[0002] Conventionally, the outer surface of a tubular member such as a pipe is painted or plated while the inner circumferential surface of the opening of the tubular member is masked. For example, Patent Document 1 below discloses a paint masking device that seals the inside of a pipe by fitting elastic disks attached to the tip of a rod-shaped grip handle via bolts and nuts to both ends of the pipe. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-169764

[0004] However, the paint masking described in Patent Document 1 has the problem that the elastic disc is made of rubber, which means that it has low sliding ability against the inner surface of the pipe, and the elastic deformation of the elastic disc makes it difficult to insert or remove it from the opening of the pipe.

[0005] The present invention has been made to address the above-mentioned problems, and its object is to provide a masking device that can improve the workability of inserting and removing a masking device from an opening of a pipe member. Summary of the Invention

[0006] In order to achieve the above object, the present invention is characterized in that it is a masking tool for masking the inner surface of a pipe member having an inner surface with a circular cross-sectional shape, and includes a masking body having a masking part that is formed in a circular cross-sectional shape and that detachably fits onto the inner surface through an opening in the pipe member to cover the inner surface, and the masking body has a rotational force receiving part that extends in a direction intersecting the circumferential direction of the masking body to receive external forces acting along the circumferential direction of the masking body.

[0007] According to this, the masking device has a rotational force receiving portion extending in a direction intersecting the circumferential direction of the masking body that masks the inner circumferential surface of the tubular member to receive external forces acting along the circumferential direction of the masking body. Therefore, the masking body can be rotated relative to the tubular member to insert or remove it, improving the operability of inserting or removing the masking body from the tubular member. This means that the positioning accuracy of the masking body within the tubular member can be improved and distortion of the masking body within the tubular member can be reduced. Furthermore, in the masking device according to the present invention, the masking body can be easily inserted or removed from the tubular member, and the masking body can be made of a softer elastic material, further improving the operability of inserting or removing the masking body.

[0008] In the paint masking of the above-mentioned prior art, the gripping handle is connected to the elastic disc by a bolt and a nut, so that the bolt or nut may loosen when the gripping handle is rotated, and the elastic disc may slide against the bolt or nut, making it difficult to insert or remove the elastic disc by rotating it.

[0009] Another feature of the present invention is that the masking tool further comprises an attachment / detachment tool for fitting or removing the masking body to the inner surface of the pipe member, and the attachment / detachment tool has a rotational force applying portion that is applied to the rotational force receiving portion to apply an external force in the circumferential direction to the rotational force receiving portion.

[0010] According to this, the masking tool is provided with an attachment / detachment tool having a rotational force applying part that is applied to the rotational force receiving part to apply a force in the circumferential direction to the rotational force receiving part, thereby improving the operability of each operation of inserting or removing the masking body. In this case, the attachment / detachment tool has a gripping part that can be held by hand, thereby improving the operability of each operation of inserting or removing the masking body by manual operation.

[0011] Another feature of the present invention is that, in the masking tool, the rotational force receiving portion has a non-circular cross-sectional shape and is formed in a concave or convex shape extending in the fitting direction with respect to the tubular member, and the rotational force imparting portion is formed in a convex or concave shape that fits freely and detachably into the rotational force receiving portion.

[0012] According to this, the masking tool has a non-circular concave or convex rotational force receiving portion, and the rotational force applying portion of the attachment / detachment tool is configured to fit into this rotational force receiving portion, so that the masking body can be rotated relative to the pipe member to insert or remove it, thereby improving the workability of each operation of inserting or removing it from the opening of the pipe member.

[0013] Here, a non-circular shape refers to a shape other than a perfect circle (a set of points located at the same distance from a certain position as the center point) (a set of points including points located at different distances from a certain position as the center point), for example, a polygonal shape such as an ellipse, triangle, square, pentagon, or hexagon, or an irregular shape (a shape whose outer edge changes irregularly).

[0014] Another feature of the present invention is that in the masking tool, the engagement length between the rotational force receiving portion and the rotational force applying portion is formed longer than the engagement length of the masking portion with the pipe member.

[0015] According to this, the masking tool is formed so that the engagement length between the rotational force receiving portion and the rotational force imparting portion is longer than the length over which the masking portion engages with the tubular member. Therefore, by making the sliding resistance (frictional resistance) between the rotational force receiving portion and the rotational force imparting portion greater than the sliding resistance (frictional resistance) between the masking portion and the tubular member, it is possible to prevent the detachable tool from coming off the masking body when the masking body is inserted or removed.

[0016] Another feature of the present invention is that, in the masking tool, the masking portion of the masking body is formed in an annular convex shape that protrudes radially outward on both end sides of the outer periphery of the masking body.

[0017] According to this, the masking device has a masking portion on the masking body formed in a ring-shaped convex shape that protrudes radially outward on both end sides of the outer periphery of the masking body, so that the sliding resistance can be lowered compared to when the masking portion is formed over the entire surface between both end sides of the outer periphery of the masking body, making it easier to insert or remove the masking body.

[0018] Another feature of the present invention is that in the masking tool, the rotational force applying portion has a first rotational force applying portion formed on the tip side in the fitting direction to the rotational force receiving portion, and a second rotational force applying portion formed rearward in the fitting direction from the first rotational force applying portion and fitting with a greater frictional force to the rotational force receiving portion than the first rotational force applying portion.

[0019] According to this, the masking tool can adjust the sliding resistance between the rotational force receiving portion and the rotational force applying portion in two stages by two fitting modes: when the first rotational force applying portion is fitted to the rotational force receiving portion, and when the second rotational force applying portion is fitted as well.Therefore, by being able to select the sliding resistance between the rotational force receiving portion and the rotational force applying portion depending on the magnitude of the sliding resistance between the masking portion and the pipe member, the workability of each operation of inserting or removing the masking body can be improved.

[0020] Another feature of the present invention is that in the masking tool, the attaching / detaching tool has a masking part pushing part that pushes the masking part of the masking body in the fitting direction of the masking part.

[0021] According to this, the masking tool and the attachment / detachment tool have a masking part pushing part that pushes the masking part of the masking main body in the fitting direction of the masking part, so that the masking main body can be smoothly inserted into the pipe member and fitted. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a cross-sectional view showing an outline of the configuration of a masking body that constitutes a masking device according to one embodiment of the present invention. [Figure 2] FIG. 2 is a front view showing the outline of the external configuration of the masking body shown in FIG. [Figure 3] FIG. 3 is a side view showing the outline of the external configuration of the attaching / detaching tool that constitutes the masking tool according to the embodiment of the present invention. [Figure 4] 4 is a front view showing the outline of the external configuration of the attachment / detachment tool shown in FIG. 3. FIG. [Figure 5] 2 is a cross-sectional view showing an outline of the configuration of a pipe member into which the masking body shown in FIG. 1 is fitted for masking. [Figure 6] 4 is a partially enlarged view of the configuration of the dashed circle 6 shown in FIG. 3. [Figure 7] 1 and 2 are partially sectional side views showing a state in which the masking bodies shown in FIGS. 1 and 2 are attached to the tip ends of the attachment / detachment tools shown in FIGS. 3 and 4, respectively. [Figure 8] 8 is a partial cross-sectional side view showing a state in which the masking body shown in FIG. 7 is press-fitted into one of the inner circumferential surfaces of the pipe member shown in FIG. 5. FIG. [Figure 9] 9(A) and 9(B) are diagrams for explaining how to rotate the attachment / detachment tool in the state shown in FIG. 8, where 9(A) is an explanatory diagram seen from the grip side of the attachment / detachment tool, and 9(B) is a cross-sectional view at the position of the masking part. [Figure 10]6 is a cross-sectional view showing a state in which the masking bodies shown in FIGS. 1 and 2 are arranged on one inner peripheral surface of the pipe member shown in FIG. 5. FIG. [Figure 11] 6 is a cross-sectional view showing a state in which the masking bodies shown in FIGS. 1 and 2 are arranged on one and the other inner circumferential surfaces of the pipe member shown in FIG. 5. FIG. [Figure 12] FIG. 10 is a front view showing the outline of the configuration of a masking body that constitutes a masking device according to a modified example of the present invention. [Figure 13] 13 is a partially cutaway side view showing a state in which the masking body shown in FIG. 12 is temporarily attached to the attachment / detachment tool that constitutes the masking tool according to another modified example of the present invention shown in FIG. 12.

[0033] FIG. [Figure 14] 1A and 1B show an outline of the configuration of a masking body constituting a masking device according to another modified example of the present invention, where 1A is a front view of the masking body and 1B is a cross-sectional view of the masking body. [Figure 15] (A) and (B) show an outline of the configuration of the detachable device that constitutes the masking device according to another modified example of the present invention shown in Figure 14, where (A) is a side view of the detachable device and (B) is a front view of the detachable device. DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, one embodiment of a masking tool according to the present invention will be described with reference to the drawings. Fig. 1 is a cross-sectional view showing the outline of the configuration of a masking body 101 constituting a masking tool 100 according to an embodiment of the present invention. Fig. 2 is a front view showing the outline of the external configuration of the masking tool 100 shown in Fig. 1. Fig. 3 is a side view showing the outline of the external configuration of an attachment / detachment tool 110 constituting the masking tool 100 according to an embodiment of the present invention. Fig. 4 is a front view showing the outline of the external configuration of the attachment / detachment tool 110 shown in Fig. 3.

[0024] Before describing the masking tool 100, we will first describe the pipe member 10, which is the object to be masked by the masking tool 100. The pipe member 10 is a cylindrical member made of resin or metal that extends in a straight or curved shape, and at least a portion of its outer surface is painted or plated. In this embodiment, as shown in FIG. 5, the pipe member 10 is a metal pipe member that forms a fuel filler opening of an automobile and is formed in a straight cylindrical shape. The outer surface and a portion of the inner circumferential surface of the pipe member 10 are subjected to cationic electrodeposition coating. In this case, the inner circumferential surfaces 12a, 12b of the pipe member 10 extending inward from the openings 11a, 11b at both ends are masked by the masking body 101 according to the present invention, thereby preventing electrodeposition coating.

[0025] (Configuration of masking tool 100) This masking tool 100 is a tool for covering inner circumferential surfaces 12a and 12b, which are other parts of the inner circumferential part of pipe member 10, to prevent electrodeposition coating when cathodic electrodeposition coating is performed on the outer circumferential surface and part of the inner circumferential surface of pipe member 10. This masking tool 100 is mainly composed of a masking body 101 and an attaching / detaching tool 110.

[0026] Masking body 101 is a device for covering and masking inner circumferential surfaces 12a, 12b of tubular member 10, and is made of a cylindrical elastic material such as rubber. In this embodiment, masking body 101 is made of silicone rubber with a durometer hardness of 50A, and is made into a cylindrical shape with a diameter of 60 mm and an axial length of 35 mm. Masking body 101 is mainly made up of masking portions 102a, 102b, inner relief portions 104a, 104b, pressure receiving portions 105a, 105b, and a rotation force receiving portion 106.

[0027] The masking portions 102a, 102b are components for covering and masking the inner peripheral surfaces 12a, 12b of the tubular member 10, and are formed on the outer peripheral surface of the masking body 101. In this case, the masking portions 102a, 102b are formed on both axial ends of the outer peripheral surface of the masking body 101, respectively, in an annular convex shape that protrudes radially outward. As a result, an outer peripheral relief portion 103 is formed between the masking portions 102a, 102b, which does not come into contact with the inner peripheral surfaces 12a, 12b of the tubular member 10, and a gap is formed between the masking portions 102a, 102b and the inner peripheral surfaces 12a, 12b.

[0028] The distance between these masking portions 102a corresponds to the length for masking the inner circumferential surfaces 12a, 12b of the tubular member 10. In this embodiment, the lengths by which the masking portions 102a and 102a engage with the inner circumferential surfaces 12a, 12b of the tubular member 10 are set to 3 mm.

[0029] The inner relief portions 104a, 104b are portions for avoiding physical interference with the attachment / detachment tool 110 when connecting the attachment / detachment tool 110 to the rotational force receiving portion 106, and are formed as bottomed holes recessed inward in the axial direction on both axial end surfaces of the masking body 101. In this case, the size (inner diameter) of each of the inner relief portions 104a, 104b is formed to be larger than the outer shape of the second rotational force applying portion 112 of the attachment / detachment tool 110.

[0030] The axial length (depth) of each of the inner recesses 104a and 104b is set to a length necessary for forming a rotational force receiving portion 106 between the inner recesses 104a and 104b. Pressure receiving portions 105a and 105b are formed radially outward at the opening portions of these inner recesses 104a and 104b, respectively.

[0031] The pressing portions 105a and 105b are portions for pressing the masking portion 102a or the masking portion 102b with the attachment / detachment tool 110, and are formed in an annular shape on both end surfaces of the masking body 101. In this case, the pressing portions 105a and 105b are formed by cutting out the both end surfaces of the masking body 101 in a conical shape to form tapered inclined surfaces.

[0032] The rotational force receiving portion 106 is a portion into which the first rotational force applying portion 111 and the second rotational force applying portion 112 of the attachment / detachment tool 110 are detachably fitted, and is configured to have a surface extending in a direction intersecting the circumferential direction to receive an external force acting along the circumferential direction of the masking body 101. More specifically, the rotational force receiving portion 106 is formed to have a concave shape with a non-circular cross section.

[0033] Here, a non-circular shape refers to a shape other than a perfect circle (a set of points at the same distance from a certain position as the center point) (a set of points at different distances from a certain position as the center point), such as an ellipse, a triangle, a rectangle, a pentagon, or a hexagon, or a polygonal shape or an irregular shape (a shape whose outer edge changes irregularly). In this embodiment, the rotational force receiving portion 106 has a substantially square cross section with a side length of 20 mm. In this case, the four corners of the rotational force receiving portion 106 are each formed in an arc shape, but of course they may also be formed at right angles.

[0034] The rotational force receiving portion 106 is formed as a through-hole in the axial center (the center in the radial direction) of the masking body 101. The length of the rotational force receiving portion 106 is set to a length that can withstand the operation of fitting the first rotational force applying portion 111 and the second rotational force applying portion 112 of the attachment / detachment tool 110 together and inserting or removing the masking body 101 into or from the inner circumferential surfaces 12a, 12b of the pipe member 10. In this embodiment, the length of the rotational force receiving portion 106 is set to 12 mm.

[0035] It should be noted that the dimensions of each part of the masking body 101 are not limited to those of this embodiment, and the above dimensions are approximate values due to the low molding precision of each part because the masking body 101 is made of a rubber material. The masking body 101 is formed symmetrically (left-right symmetry in FIG. 1) between the masking part 102a side and the masking part 102b side by the masking parts 102a, 102b, the inner relief parts 104a, 104b, the pressure receiving parts 105a, 105b, and the rotation force receiving part 106.

[0036] The attachment / detachment tool 110 is an instrument for inserting or removing the masking body 101 into or from the openings 11a, 11b of the pipe member 10, and is made of a rod-shaped metal or resin material. In this embodiment, the attachment / detachment tool 110 is made of aluminum. The attachment / detachment tool 110 is made up of a first power application unit 111, a second power application unit 112, a push-in assist unit 113, a stopper 115, and a grip unit 116.

[0037] The first power application part 111 is a part that fits into the rotational force receiving part 106 of the masking body 101, and is configured to have a surface that is applied to the rotational force receiving part 106 in order to apply an external force in the circumferential direction to the rotational force receiving part 106. Specifically, the first power application part 111 is formed at the tip of the attachment / detachment tool 110 in the shape of a rod with a square cross section that corresponds to the rotational force receiving part 106.

[0038] The first power applying portion 111 is formed to have an outer shape that is slightly smaller than the inner shape of the rotational force receiving portion 106, that is, a size that provides a so-called clearance fit. In this embodiment, the first power applying portion 111 is formed to have a substantially square cross section with a side length of 19.9 mm.

[0039] In this case, the four corners of the first power application portion 111 are each formed into a chamfered slope, but it goes without saying that they may be formed into an arc shape or a right angle. Also, the length of the first power application portion 111 is formed to be shorter than the length of the rotational force receiving portion 106, but may be formed to be the same length as or longer than the rotational force receiving portion 106.

[0040] The second rotational force applying portion 112 is a portion that fits into the rotational force receiving portion 106 of the masking body 101, and is configured to have a surface that is applied to the rotational force receiving portion 106 in order to apply an external force in the circumferential direction to the rotational force receiving portion 106. Specifically, the second rotational force applying portion 112 is formed in a rod shape with a square cross section that corresponds to the rotational force receiving portion 106 at a position adjacent to the first rotational force applying portion 111 in the attachment / detachment tool 110.

[0041] 6, the second rotational force applying portion 112 is formed to have an outer shape that is slightly larger than the inner shape of the rotational force receiving portion 106, that is, a size that provides a so-called tight fit. In this embodiment, the second rotational force applying portion 112 is formed to have a substantially square cross section with a side length of 20.1 mm.

[0042] In this case, the four corners of the second rotational force applying portion 112 are each formed into a chamfered slope, but of course they may be formed into an arc shape or a right angle. Also, the length of the second rotational force applying portion 112 is formed to be shorter than the lengths of the first rotational force applying portion 111 and the rotational force receiving portion 106, but may be formed to be the same length as or longer than the lengths of the first rotational force applying portion 111 and the rotational force receiving portion 106.

[0043] The push-in assisting portion 113 is a portion for assisting the operation of pushing the masking body 101 into the tubular member 10, and is formed in the shape of a round bar extending in the axial direction at a position adjacent to the second power applying portion 112. Specifically, the push-in assisting portion 113 pushes the masking body 101 into the tubular member 10 and determines the installation position of the masking body 101 within the tubular member 10. For this reason, the push-in assisting portion 113 is formed with an outer diameter smaller than the inner diameter of the tubular member 10 so as to be insertable into the tubular member 10, and is formed with a length corresponding to the distance from the installation position of the masking body 101 within the tubular member 10 to the openings 11a and 11b. The push-in assisting portion 113 has a masking portion pushing portion 114 formed at one end (the right side in the figure) and a stopper 115 formed at the other end.

[0044] Masking portion pressing portion 114 is a portion for pressing masking portions 102a, 102b in the axial direction of masking body 101, in other words, in the direction of insertion into tubular member 10, by pressing pressure receiving portion 105a or pressure receiving portion 105b of masking body 101. Specifically, masking portion pressing portion 114 has an annular end face portion that presses pressure receiving portions 105a, 105b and is configured as a conical inclined surface that closely contacts pressure receiving portions 105a, 105b. In addition, the outer diameter of masking portion pressing portion 114 is formed to be smaller than the outer diameters of pressure receiving portions 105a, 105b.

[0045] The stopper 115 is a part that regulates the insertion of the first power application part 111 and the second power application part 112 into the tubular member 10 and also receives the hand that grips the gripping part 116 when pushing the attachment / detachment tool 110 into the masking body 101, and is formed in the shape of a flat, annular flange that has a diameter larger than the inner diameter of the tubular member 10 and extends radially outward beyond the outer surface of the pushing-in auxiliary part 113.

[0046] The gripping portion 116 is the portion that the operator grips with his / her hand when pushing the attaching / detaching tool 110 into the masking body 101, and is formed in the shape of a round bar extending in the axial direction at a position adjacent to the stopper 115. In this case, the outer surface of the gripping portion 116 is knurled to prevent slipping. Note that in Figure 3, part of the shape of the gripping portion 116 that extends in the axial direction is omitted to reduce its length.

[0047] (Operation of masking tool 100) Next, the operation of the masking tool 100 configured as described above will be described. First, the worker prepares the tubular member 10 and the masking tool 100. In this case, the worker prepares the number of masking bodies 101 corresponding to the number of locations that need to be masked for one tubular member 10. In this embodiment, the worker prepares two masking bodies 101 and one attaching / detaching tool 110 to mask the inner circumferential surfaces 12a, 12b at both ends of one tubular member 10, respectively.

[0048] Next, the worker attaches the masking body 101 to the attachment / detachment tool 110. Specifically, as shown in FIG. 7 , the worker inserts the first power application unit 111 and the second power application unit 112 of the attachment / detachment tool 110 into the rotational force receiving unit 106 of the masking body 101. In this case, the worker may insert only the first power application unit 111 of the attachment / detachment tool 110 into the rotational force receiving unit 106 of the masking body 101, or may insert both the first power application unit 111 and the second power application unit 112 of the attachment / detachment tool 110 into the rotational force receiving unit 106 of the masking body 101. In this way, the masking body 101 is temporarily attached to the tip of the attachment / detachment tool 110 by fitting only the first power application unit 111 or the second power application unit 112 of the attachment / detachment tool 110.

[0049] Since the masking body 101 is formed symmetrically on the masking portion 102a side and the masking portion 102b side, the operator may insert the first power application portion 111 of the attachment / detachment tool 110 from either the masking portion 102a side or the masking portion 102b side.

[0050] Next, the worker fits the masking body 101 into one of the openings 11a, 11b of the tubular member 10 to mask the inner circumferential surfaces 12a, 12b. Specifically, as shown in Fig. 8, the worker holds and operates the gripping portion 116 of the attachment / detachment tool 110 to insert the masking body 101 into the opening 11a (or opening 11b) of the tubular member 10. In this case, the worker pushes the attachment / detachment tool 110 to push the masking body 101 in the axial direction of the tubular member 10, thereby press-fitting the masking body 101 into the openings 11a, 11b of the tubular member 10.

[0051] In this case, when the attachment / detachment device 110 is pushed toward the masking body 101 with only the first power application part 111 fitted into the rotational force receiving part 106, the second power application part 112 is formed with an outer shape slightly larger than that of the first power application part 111, so that it can press the end face around the opening of the rotational force receiving part 106 and press the masking body 101 into the pipe member 10.

[0052] 9(A) and 9(B), the worker rotates the attachment / detachment tool 110 around the axis of the gripping part 116 (see the dashed arrow), causing the first power application part 111 and / or the second power application part 112 to press against the rotational force receiving part 106. This allows the worker to press the masking body 101 into the openings 11a and 11b of the pipe member 10 by rotating the masking body 101 inside the pipe member 10 and pushing it into the openings 11a and 11b.

[0053] Furthermore, when the attaching / detaching tool 110 is pushed toward the masking body 101 with only the first power imparting part 111 fitted into the rotational force receiving part 106, if the frictional force between the inner circumferential surface 12a (or inner circumferential surface 12b) and the masking parts 102a, 102b is greater than the frictional force between the rotational force receiving part 106 and the first power imparting part 111 and / or the fitting resistance of the second power imparting part 112 to the rotational force receiving part 106, the second power imparting part 112 is press-fitted into and fitted into the rotational force receiving part 106. This allows the attaching / detaching tool 110 to press-fit the masking body 101 into the openings 11a, 11b of the pipe member 10 via the frictional force between the rotational force receiving part 106 and the second power imparting part 112, which is greater than the frictional force between the rotational force receiving part 106 and the first power imparting part 111.

[0054] Furthermore, in the attaching / detaching tool 110, when the frictional force between the inner circumferential surface 12a (or inner circumferential surface 12b) and the masking portions 102a, 102b is greater than the frictional force between the rotational force receiving portion 106 and the second rotational force applying portion 112, the second rotational force applying portion 112 is further pressed into the rotational force receiving portion 106, and the masking portion pressing portion 114 comes into contact with and presses the pressure receiving portions 105a, 105b. This allows the attaching / detaching tool 110 to press the masking body 101 into the opening 11a (or opening 11b) of the pipe member 10 also by the force with which the masking portion pressing portion 114 presses the pressure receiving portions 105a, 105b.

[0055] The masking body 101 is pushed into the opening 11a (or opening 11b) of the tubular member 10 until the area between the masking portions 102a and 102b covers the entire portion of the inner circumferential surface 12a (or inner circumferential surface 12b) in the tubular member 10 that requires masking. In this case, as shown in FIG. 10 , the length of the push-in assist portion 113 of the attachment / detachment tool 110 is formed to correspond to the distance from the installation position of the masking body 101 to the opening 11a or opening 11b in the tubular member 10. Therefore, the operator can position the masking body 101 at a predetermined position in the tubular member 10 by pushing the attachment / detachment tool 110 until the stopper 115 hits the opening 11a (or opening 11b) of the tubular member 10.

[0056] As a result, both ends of the portion of the inner peripheral surface 12a (or inner peripheral surface 12b) within the pipe member 10 that requires masking are blocked by the masking portions 102a, 102b, and the entire portion that requires masking is covered and masked by the masking portions 102a, 102b and the outer peripheral relief portion 103.

[0057] In addition, if the masking state of the inner surfaces 12a, 12b is insufficient because the masking body 101 is pressed into the pipe member 10 in a distorted shape, or if undue stress is being applied to the masking body 101 and there is a risk of damage, the worker can adjust the deformation state or posture of the masking body 101 within the pipe member 10 by rotating the attachment / detachment device 110.

[0058] Next, the worker removes the detachable tool 110 from the masking body 101. Specifically, the worker operates the detachable tool 110 to pull out the first power application unit 111 and the second power application unit 112 from the rotational force receiving unit 106. In this case, if the position of the masking body 101 changes along with the detachable tool 110 when the worker pulls the detachable tool 110 out of the rotational force receiving unit 106, the worker can remove the detachable tool 110 from the masking body 101 while suppressing displacement of the masking body 101 by tilting the detachable tool 110 with respect to the central axis of the masking body 101 to elastically deform the rotational force receiving unit 106, or by pulling out the detachable tool 110 while holding the outer edges of the pressure receiving units 105a and 105b with their hands.

[0059] Although the worker inserted the masking body 101 into the pipe member 10 by pushing the attachment / detachment tool 110 toward the pipe member 10, it is of course also possible to insert the masking body 101 into the pipe member 10 by pushing the pipe member 10 toward the attachment / detachment tool 110, and the displacement of the two is relative.

[0060] Next, as shown in Fig. 11, the worker fits the masking body 101 into the other opening 11b (or opening 11a) of the pipe member 10 in the same procedure as described above to mask the inner circumferential surface 12b (or inner circumferential surface 12a). In this way, the worker can fit the masking body 101 into the openings 11a, 11b at both ends of the pipe member 10, respectively, to mask the inner circumferential surfaces 12a, 12b at both ends.

[0061] Next, the worker performs cationic electrodeposition coating on the pipe member 10. This cationic electrodeposition coating is a well-known technique, and therefore a description thereof will be omitted. In this cationic electrodeposition coating, the inner circumferential surfaces 12a, 12b of the pipe member 10 at both ends are masked by the masking bodies 101, respectively, and therefore the electrodeposition coating is prevented. In this cationic electrodeposition coating, since the masking body 101 is formed in a cylindrical shape and has a through-hole-shaped rotational force receiving portion 106, the cationic electrodeposition coating is applied to the entire inner circumferential surface of the pipe member 10 other than the portions masked by the two masking bodies 101.

[0062] Next, the worker removes the masking body 101 from the pipe member 10 that has been subjected to cationic electrodeposition coating. First, the worker connects the attaching / detaching tool 110 to the masking body 101 that is fitted into the opening 11a (or opening 11b) of the pipe member 10.

[0063] Specifically, the worker inserts the first power application part 111 and the second power application part 112 into the rotational force receiving part 106 of the masking body 101 that is fitted into one of the openings 11a (or opening 11b) of the tubular member 10. In this case, the worker may insert only the first power application part 111 of the attachment / detachment tool 110 into the rotational force receiving part 106 of the masking body 101, or may insert not only the first power application part 111 of the attachment / detachment tool 110 but also the second power application part 112 into the rotational force receiving part 106 of the masking body 101. In this way, the attachment / detachment tool 110 is connected to the masking body 101 that is fitted into one of the openings 11a (or opening 11b) of the tubular member 10.

[0064] Next, the worker operates the attachment / detachment tool 110 to pull out the masking body 101 fitted into one of the openings 11a (or opening 11b) of the pipe member 10. In this case, the worker can pull the attachment / detachment tool 110 in the axial direction of the pipe member 10, rotate the attachment / detachment tool 110 around the axis of the gripping portion 116, or tilt the attachment / detachment tool 110 (see FIG. 8 ) to pull the masking body 101 while rotating or elastically deforming it within the opening 11a (or opening 11b), thereby pulling the masking body 101 out.

[0065] When the masking body 101 is pulled out from the opening 11a (or opening 11b), the worker pulls out the first power application part 111 and the second power application part 112 from the rotation force receiving part 106 of the pulled out masking body 101. Then, the worker can pull out the masking body 101 fitted into the other opening 11b (or opening 11a) of the tubular member 10 in the same procedure. The two masking bodies 101 removed from the tubular member 10 can be reused to mask another new tubular member 10.

[0066] The worker can also pull out the masking body 101 from inside the tubular member 10 by hooking a finger or an implement other than the attachment / detachment tool 110 onto the rotational force receiving portion 106 of the masking body 101 fitted inside the tubular member 10. In other words, the worker can pull out the masking body 101 from inside the tubular member 10 without using the attachment / detachment tool 110.

[0067] As can be understood from the above description of operation, according to the above embodiment, the masking tool 100 has a rotational force receiving portion 106 that extends in a direction intersecting the circumferential direction of the masking body 101 that masks the inner surfaces 12a, 12b of the pipe member 10 to receive external forces acting along the circumferential direction of the masking body 101. Therefore, the masking body 101 can be inserted or removed by rotating it relative to the pipe member 10, thereby improving the workability of each operation of inserting or removing the masking body 101 relative to the pipe member 10.

[0068] This means that the positioning accuracy of the masking body 101 within the tubular member 10 can be improved, and that the masking body 101 can be installed within the tubular member 10 while suppressing distortion. Furthermore, in the masking tool 100 according to the present invention, the masking body 101 can be easily inserted and removed from the tubular member 10, and since the masking body 101 can be made of a softer elastic body, the workability of inserting and removing the masking body 101 can be further improved.

[0069] Furthermore, the present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the scope of the present invention. In the description of each modification, the same parts as those in the above-described embodiment are designated by the same reference numerals, and redundant description will be omitted.

[0070] For example, in the above embodiment, the masking body 101 is configured to have two masking portions 102a, 102b at both ends of its outer periphery to mask the inner periphery of the pipe member 10. According to this, the masking tool 100 has masking portions 102a, 102b formed in annular convex shapes on the outer periphery of the masking body 101, and therefore, compared to a case in which masking portions are formed on the entire surface between both ends of the outer periphery of the masking body 101, sliding resistance can be reduced, and the operations of inserting and removing the masking body 101 can be made easier.

[0071] However, the masking portions 102a and 102b are formed according to the regions of the inner peripheral surface of the pipe member 10 that require masking. Therefore, it is sufficient that at least one masking portion 102a and one masking portion 102b are provided on the outer peripheral portion of the masking body 101. For example, the masking portions 102a and 102b may each be composed of only one of the masking portion 102a and the masking portion 102b, or may each be composed of three or more masking portions 102a and 102b. Furthermore, the masking portions 102a and 102b may each be composed of the masking portion 102a and the masking portion 102b connected together. In this case, the masking body 101 is configured without the outer peripheral relief portion 103.

[0072] Furthermore, in the above embodiment, the masking body 101 is made of an elastic body such as rubber or elastomer that is elastically deformable when inserted into, removed from, or placed inside the tubular member 10. In this case, the hardness of the elastic body that makes up the masking body 101 is set appropriately depending on the material of the tubular member 10 or the masking specifications, and is naturally not limited to the above embodiment.

[0073] Furthermore, the masking body 101 can be made of a rigid metal material in addition to an elastic material. In this case, the metal masking body 101 is fitted to the pipe member 10 in a so-called interference fit relationship, and therefore, strictly speaking, it undergoes elastic deformation, but is defined as a rigid body to distinguish it from materials that undergo significant elastic deformation, such as rubber or elastomer. In this case, the masking body 101 can have the masking portions 102a and 102b made of an elastic material, while the remaining portions can be made of a rigid material such as a metal material.

[0074] In the above embodiment, the cross section of the rotational force receiving portion 106 of the masking body 101 is formed to be square. However, the rotational force receiving portion 106 can be formed to be other non-circular shapes that allow the masking body 101 to rotate reliably. For example, the cross section of the rotational force receiving portion 106 can be formed to be a quadrangle other than a square (e.g., a rectangle or a diamond), a polygonal shape such as an oval, a triangle, a square, a pentagon, or a hexagon, or an irregular shape (a shape with an irregularly changing outer edge). In this case, it goes without saying that the cross sections of the first rotational force applying portion 111 and the second rotational force applying portion 112 of the attachment / detachment tool 110 are formed to be shapes that correspond to the cross section of the rotational force receiving portion 106.

[0075] In the above embodiment, the rotational force receiving portion 106 is configured as a through hole. However, the rotational force receiving portion 106 can also be configured as a hole with a bottom. In this way, the masking body 101 can perform masking by preventing paint from entering the inner side of the pipe member 10 where the masking body 101 is fitted.

[0076] In the above embodiment, the rotational force receiving portion 106 is formed in a square shape centered on the central axis of the cylindrically formed masking body 101. However, the rotational force receiving portion 106 can be formed around a position other than the central axis of the cylindrically formed masking body 101. In other words, the rotational force receiving portion 106 can be formed in an area more inward than the masking portions 102a and 102b.

[0077] In the above embodiment, the attaching / detaching tool 110 is configured to include two rotation force applying units, the first rotation force applying unit 111 and the second rotation force applying unit 112, and to fit into the rotation force receiving unit 106 of the masking body 101. That is, the first rotation force applying unit 111 and the second rotation force applying unit 112 correspond to the rotation force applying unit according to the present invention. However, it is sufficient for the rotation force applying unit to be able to removably fit into the rotation force receiving unit 106 and reliably rotate the masking body 101. Therefore, the rotation force applying unit may be configured with only one of the first rotation force applying unit 111 and the second rotation force applying unit 112, or may be configured with three or more rotation force applying units.

[0078] Furthermore, in the above embodiment, the first power application portion 111 is configured to fit with the rotational force receiving portion 106 in a so-called clearance fit relationship. However, the first power application portion 111 may also be configured to fit with the rotational force receiving portion 106 in a so-called interference fit relationship. In this case, if the first power application portion 111 has the second power application portion 112, it is preferable that the first power application portion 111 be formed to fit with the rotational force receiving portion 106 in a looser interference fit relationship than the second power application portion 112.

[0079] In the above embodiment, the length of the rotational force receiving portion 106 is 12 mm, and the lengths of the masking portions 102a, 102b are 6 mm. That is, in the masking tool 100, the engagement length between the rotational force receiving portion 106 and the first and second rotational force applying portions 111, 112 is longer than the engagement length between the inner circumferential surfaces 12a, 12b of the tubular member 10 and the masking portions 102a, 102b. This makes the sliding resistance (frictional resistance) between the rotational force receiving portion 106 and the first and second rotational force applying portions 111, 112 greater than the sliding resistance (frictional resistance) between the masking portions 102a, 102b and the tubular member 10, thereby preventing the attaching / detaching device 110 from coming off the masking body 101 when the masking body 101 is inserted or removed. However, the engagement length between the rotational force receiving portion 106 and the first and second rotational force applying portions 111 and 112 can also be formed to be the same as or shorter than the engagement length between the inner circumferential surfaces 12a, 12b of the tubular member 10 and the masking portions 102a, 102b.

[0080] In the above embodiment, the attaching / detaching tool 110 is configured to include a push-in auxiliary part 113, a masking part pushing part 114, and a stopper 115 that push the masking parts 102a, 102b of the masking body 101 in the fitting direction of the masking parts 102a, 102b and determine the installation position of the masking body 101. This enables the attaching / detaching tool 110 to smoothly insert the masking body 101 into the pipe member 10 and fit it with good positioning accuracy. However, the attaching / detaching tool 110 can also be configured without the push-in auxiliary part 113, the masking part pushing part 114, and the stopper 115.

[0081] Furthermore, in the above embodiment, the masking tool 100 has the rotational force receiving portion 106 formed in a concave shape, and the first rotational force applying portion 111 and the second rotational force applying portion 112 formed in a convex shape that fits into the rotational force receiving portion 106. However, the masking tool 100 may also have the rotational force receiving portion 106 formed in a convex shape, and the first rotational force applying portion 111 and the second rotational force applying portion 112 formed in a concave shape that fits into the rotational force receiving portion 106.

[0082] In the above embodiment, the cross-sectional shapes of the rotational force receiving portion 106, the first rotational force applying portion 111, and the second rotational force applying portion 112 of the masking tool 100 are each formed to be non-circular. However, it is sufficient that the rotational force receiving portion 106, the first rotational force applying portion 111, and the second rotational force applying portion 112 are configured so as to be able to rotate the masking body 101 in the circumferential direction.

[0083] 12 and 13, the masking tool 100 can be configured to include a rotational force receiving portion 106, a first rotational force applying portion 111, and a second rotational force applying portion 112, each of which has a circular cross section. Specifically, the masking body 101 can have the rotational force receiving portion 120 formed by two through-holes that penetrate in the axial direction around the center of the masking body 101. In this case, a positioning hole 121 made of a through-hole for positioning the attaching / detaching tool 110 can be formed in the center of the masking body 101.

[0084] Furthermore, the attachment / detachment tool 110 can be formed with a rotation force imparting part 122 made of two round bars protruding in the axial direction from the periphery of the center on the tip surface of the masking part pressing part 114. In this case, a round bar-shaped positioning shaft 123 that detachably fits into the positioning hole 121 can be formed in the center of the masking part pressing part 114 of the attachment / detachment tool 110.

[0085] When using the masking tool 100 configured in this manner, the worker fits the positioning shaft 123 of the attaching / detaching tool 110 into the positioning hole 121 of the masking body 101, and fits the two rotation force applying parts 122 into the two rotation force receiving parts 106, thereby holding the masking body 101 on the attaching / detaching tool 110. Then, when inserting the masking body 101 into the tubular member 10, the worker can insert the masking body 101 while rotating it inside the tubular member 10 by rotating the attaching / detaching tool 110.

[0086] 14 and 15, the masking tool 100 can have first and second power application sections 111 and 112 configured by alternately arranging convex portions and concave portions on a circumference. Specifically, the masking body 101 is configured by forming block-shaped rotational force receiving sections 130, which protrude in an axial direction and are arranged intermittently and at equal intervals in the circumferential direction (eight in FIG. 14), on the outer edge portions of each of both end faces of the masking body 101. In this case, the rotational force receiving sections 130 and the concave portions formed between adjacent rotational force receiving sections 130 (sections into which the rotational force application sections 131 fit) also serve as pressure receiving sections 105a and 105b.

[0087] The attaching / detaching device 110 is configured such that rotational force imparting portions 131 are formed intermittently (eight in FIG. 15 ) at equal intervals in the circumferential direction on the outer edge portion of the tip surface of the masking portion pressing portion 114. The rotational force imparting portions 131 are recessed in the axial direction and are closed-end holes into which the rotational force receiving portions 130 are detachably fitted. In this case, the rotational force imparting portions 131 and the portions formed in a convex shape between adjacent rotational force imparting portions 131 (portions into which the rotational force receiving portions 130 fit) also serve as the masking portion pressing portion 114.

[0088] When using the masking tool 100 configured in this manner, the worker fits the positioning shaft 123 of the attaching / detaching tool 110 into the positioning hole 121 of the masking body 101, while fitting the concave rotation force applying portion 131 into the convex rotation force receiving portion 130, thereby holding the masking body 101 in the attaching / detaching tool 110. Then, when inserting the masking body 101 into the tubular member 10, the worker rotates the attaching / detaching tool 110, thereby allowing the masking body 101 to be inserted while rotating inside the tubular member 10.

[0089] Furthermore, in the above embodiment, the masking tool 100 is configured to include the attaching / detaching tool 110. However, the masking tool 100 can be configured without the attaching / detaching tool 110. In this case, the operator can insert the masking body 101 while rotating it within the pipe member 10, for example, by grasping the rotation force receiving portion 130 (see FIG. 14) with his / her hand and rotating it in the circumferential direction.

[0090] In the above embodiment, the masking tool 100 was used to mask the pipe member 10 that was to be subjected to cathodic electrodeposition coating. However, it goes without saying that the masking tool 100 can also be used to mask the pipe member 10 that is to be subjected to coating other than cathodic electrodeposition coating or plating. [Explanation of symbols]

[0091] 10...pipe member, 11a, 11b...opening, 12a, 12b...inner peripheral surface, 100...Masking tools, 101...masking body, 102a, 102b...masking portion, 103...outer peripheral relief portion, 104a, 104b...inner relief portion, 105a, 105b...pressure receiving portion, 106...rotation force receiving portion, 110...attachment / detachment tool, 111...first power application unit, 112...second power application unit, 113...pushing assist unit, 114...masking unit pushing unit, 115...stopper, 116...gripping unit, 120...rotation force receiving portion, 121...positioning hole, 122...rotation force applying portion, 123...positioning shaft, 130...rotational force receiving portion, 131...rotational force applying portion.

Claims

1. A masking tool for masking an inner peripheral surface of a pipe member having an inner peripheral surface with a circular cross section, a masking body having a masking part that has a circular cross section and is detachably fitted onto the inner circumferential surface through an opening of the pipe member to cover the inner circumferential surface, The masking body is A masking tool characterized by having a rotational force receiving portion extending in a direction intersecting the circumferential direction of the masking body to receive an external force acting along the circumferential direction of the masking body.

2. The masking device according to claim 1, further comprising: a detachment tool for fitting or removing the masking body to or from the inner circumferential surface of the pipe member; The attachment / detachment tool is A masking tool comprising a rotational force applying portion that is applied to the rotational force receiving portion in order to apply an external force in the circumferential direction to the rotational force receiving portion.

3. The masking device according to claim 2, The rotation force receiving portion is The cross section is formed in a non-circular shape and is formed in a concave or convex shape extending in the fitting direction with respect to the pipe member, The rotation force applying unit is A masking tool characterized in that it is formed in a convex or concave shape that can be detachably fitted into the rotational force receiving portion.

4. The masking device according to claim 3, A masking tool characterized in that the length of engagement between the rotational force receiving portion and the rotational force applying portion is formed longer than the length of engagement of the masking portion with the tubular member.

5. The masking device according to claim 3, The masking portion of the masking body is A masking tool characterized in that the masking body is formed with an annular convex shape that protrudes radially outward on both end sides of the outer periphery thereof.

6. The masking device according to claim 3, The rotation force applying unit is a first rotation force applying portion formed on a tip end side in a fitting direction to the rotation force receiving portion; a second rotational force applying portion formed rearward of the first rotational force applying portion in the fitting direction and adapted to fit with a greater frictional force against the rotational force receiving portion than the first rotational force applying portion.

7. The masking device according to claim 3, The attachment / detachment tool is A masking tool characterized by having a masking portion pushing portion that pushes the masking portion of the masking body in a fitting direction of the masking portion.

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