Dust cap for eye joint

Abstract

The present invention eliminates the necessity of manufacturing a dust cap for an eye joint for each type of a variety of eye joint metal fittings and reduces manufacturing volume and storage space to cut the costs of dust caps for eye joints.　This dust cap for an eye joint comprises: a pair of lid parts 12, 14 covering end surface parts on both sides of an eye joint body; and a connection piece 16 connecting the pair of lid parts 12, 14. One lid part 12 includes a lid plate part 1202 covering the end surface part, and a cylindrical part 1204 protruding from the lid plate part 1202. The other lid part 14 includes a lid plate part 1402 covering the end surface part, and a shaft part 1404 protruding from the lid plate part 1402, and has a holding part 18 that releasably holds a state in which the shaft part 1404 is inserted in the cylindrical part 1204. The cylindrical part 1204 and the shaft part 1404 are detachably mounted to the lid plate parts 12, 14, respectively.

Description

Dust cap for eye joint

[0001] The present invention relates to a dust cap for an eye joint.

[0002] Eye joint fittings are used together with eye bolts (union bolts) to connect hoses and other equipment. Eye joint fittings often include a metal eye joint body with an eye bolt insertion hole formed therethrough, and a tube that protrudes from the eye joint body and is connected to the hose.

[0003] The eye bolt has a flow path extending inside its shaft, a first opening formed at the part of the shaft that is positioned inside the eye bolt insertion hole when the eye bolt is inserted into the eye bolt insertion hole and that communicates with the flow path, and a second opening formed at the tip surface of the shaft or on the outer surface of the shaft that protrudes from the eye bolt insertion hole and that communicates with the flow path.

[0004] The eyebolt insertion hole has an inner diameter at both ends to allow the shank of the eyebolt to pass through, and openings are provided on both end faces of the eye joint body. The middle portion of the eyebolt insertion hole has a large diameter portion with an inner diameter larger than the opening to facilitate communication with the first opening of the eyebolt.

[0005] The eye joint fitting is attached to the equipment side by placing one of the end faces on both sides of the eye joint body on the surface of the equipment side via an annular sealing member, and with an annular sealing member placed on the other end face, inserting the eye bolt into the eye bolt insertion hole of the eye joint body, the underside of the eye bolt head elastically contacting the other end face via the sealing member, and screwing the male thread of the eye bolt shaft into the female thread on the equipment side.

[0006] Therefore, the end faces on both sides of the eye joint body where the eyebolt insertion hole opening is provided serve as sealing surfaces, and scratches on these surfaces can cause fluid leakage during use. To prevent scratches on the sealing surfaces on both sides of the eye joint body, eye joint dust caps are used. Conventional eye joint dust caps include a pair of lids covering both end faces of the eye joint body. One of the pair of lids has a cover plate covering the end face and a tubular portion protruding from the cover plate and having an inner circumferential surface and an outer circumferential surface with an outer diameter smaller than the inner diameter of the opening. The other of the pair of lids has a cover plate covering the end face and a shaft portion protruding from the cover plate and having an outer circumferential surface that is removably inserted into the inner circumferential surface of the tubular portion. The pair of lids is maintained in contact with the end faces on both sides of the eye joint body by friction between the inner circumferential surface of the tubular portion and the outer circumferential surface of the shaft portion.

[0007] Japanese Patent Application Laid-Open No. 2020-133731

[0008]

[0003] Meanwhile, there are various types of eye joint fittings, such as the size of the end face of the eye joint body and the thickness of the eye joint body in the axial direction. While conventional eye joint dust caps can accommodate some axial thickness of the eye joint body by changing the connection length between the tubular portion and the shank, they cannot accommodate large differences in the size of the end face of the eye joint body or the thickness of the eye joint body in the axial direction, and a new eye joint dust cap must be manufactured each time, which is inconvenient in terms of reducing costs.

[0004] The present invention has been made in consideration of the above circumstances, and its object is to provide an eye joint dust cap that can accommodate various eye joint fittings by combining and using parts that match the size of the end face of the eye joint body and parts that match the inner diameter and thickness of the eye joint body in the axial direction, thereby eliminating the need to manufacture a new eye joint dust cap for each different eye joint fitting, and is advantageous in reducing production volume and storage space, thereby reducing costs.

[0009] In order to achieve the above-mentioned object, one embodiment of the present invention is a dust cap for an eye joint comprising a pair of lid portions covering both end surface portions of an eye joint body in which an opening for an eyebolt insertion hole is provided, and a connecting piece connecting the pair of lid portions, wherein one of the pair of lid portions has a lid plate portion covering the end surface portion and a tubular portion protruding from the lid plate portion and having an inner circumferential surface and an outer circumferential surface with an outer diameter smaller than the inner diameter of the opening, and the other of the pair of lid portions has a lid plate portion covering the end surface portion and a shank portion protruding from the lid plate portion and having an outer circumferential surface that is inserted into the inner circumferential surface of the tubular portion, and is provided with a retaining portion that releasably holds the shank inserted into the tubular portion, and wherein at least one of the tubular portion and the shank portion is detachably provided on the lid plate portion. Furthermore, one embodiment of the present invention is characterized in that, in the one lid portion and the other lid portion, the tubular portion and the shaft portion are detachably provided on the cover plate portion, the cover plate portion of the one lid portion is provided with a tubular portion insertion hole that allows the tubular portion to be inserted therethrough, the tubular portion is provided integrally with the tubular portion at an end portion in the axial direction of the tubular portion and has a tubular portion locking portion that can be engaged with a portion of the cover plate around the tubular portion insertion hole, the cover plate portion of the other lid portion is provided with a shaft portion insertion hole that allows the shaft portion to be inserted therethrough, the shaft portion is provided integrally with the shank at an end portion in the axial direction of the shaft portion and has a shaft portion locking portion that can be engaged with a portion of the cover plate around the shaft portion insertion hole, and the cover plate portion of the one lid portion, the cover plate portion of the other lid portion, and the connecting piece are provided integrally. In addition, one embodiment of the present invention is characterized in that a first fitting portion is provided on the inner peripheral portion of the tubular portion insertion hole of the cover plate portion and on the end of the outer peripheral surface of the tubular portion facing the tubular portion locking portion when the tubular portion is attached to the cover plate portion, thereby preventing the tubular portion from rotating relative to the cover plate portion, and a second fitting portion is provided on the inner peripheral portion of the shaft portion insertion hole of the cover plate portion and on the end of the outer peripheral surface of the shaft portion facing the shank locking portion when the shaft portion is attached to the cover plate portion, thereby preventing the shaft portion from rotating relative to the cover plate portion.In one embodiment of the present invention, the one of the lids has a cylindrical portion detachably attached to the cover plate, a cylindrical portion insertion hole formed in the cover plate of the one of the lids to allow insertion of the cylindrical portion, the cylindrical portion having a cylindrical portion locking portion formed integrally with the cylindrical portion at an end in an axial direction of the cylindrical portion and lockable to a portion of the cover plate around the cylindrical portion insertion hole, and the shaft, the cover plate of the one of the lids, the cover plate of the other lid, and the connecting piece are integrally formed. In another embodiment of the present invention, the one of the lids has a cylindrical portion insertion hole formed in the cover plate to allow insertion of the cylindrical portion, the cylindrical portion having a cylindrical portion locking portion formed integrally with the cylindrical portion at an end in an axial direction of the cylindrical portion and lockable to a portion of the cover plate around the cylindrical portion insertion hole, and the shaft, the cover plate of the one of the lids, and the cover plate of the other lid are integrally formed with the connecting piece. In one embodiment of the present invention, the shaft is detachably mounted on the cover plate of the other lid, the cover plate of the other lid is provided with a shaft insertion hole that allows the shaft to be inserted therethrough, the shaft is integral with the shank at an axial end of the shaft and has a shaft locking portion that can lock to a portion of the cover plate around the shaft insertion hole, and the cylindrical portion, the cover plate of the one lid, the cover plate of the other lid, and the connecting piece are integrally formed. In another embodiment of the present invention, the shaft is detachably mounted on the cover plate of the other lid, the shaft insertion hole is provided at an inner periphery of the shaft insertion hole and at an end of the outer periphery of the shaft on the shaft locking portion side, and the connecting piece is integrally formed with the shank. In one embodiment of the present invention, the retaining portion is an inner peripheral surface of the cylindrical portion and an outer peripheral surface of the shaft portion that detachably retain the inserted state of the shaft portion in the cylindrical portion by friction.In another embodiment of the present invention, the retaining portion is an uneven portion that is provided on the inner peripheral surface of the cylindrical portion and the outer peripheral surface of the shaft portion and that detachably retains the inserted state of the shaft portion in the cylindrical portion.

[0010] According to one embodiment of the present invention, at least one of the tubular portion and the shank is detachably attached to the cover plate, so that an eye joint dust cap is used that combines a part that matches the size of the end face of the eye joint body and a part that matches the axial inner diameter and thickness of the eye joint body. This eliminates the need to manufacture eye joint dust caps for various eye joint fittings, which is advantageous in reducing production volume and storage space, thereby reducing the cost of eye joint dust caps. Furthermore, if the tubular portion and shank are detachably attached to the cover plate of one cover and the other cover, and the cover plate and connecting piece of the one cover and the other cover are integrally formed, then selecting and combining the tubular portion, shank, and cover plate that are suitable for the eye joint body will be advantageous in reducing production volume and storage space, thereby reducing costs. Furthermore, if a cylindrical portion locking portion that can be locked to the cover plate is provided integrally with the cylindrical portion at the axial end of the cylindrical portion, and a shaft portion locking portion that can be locked to the cover plate is provided integrally with the shaft at the axial end of the shaft, this is advantageous in preventing the cylindrical portion and shaft portion from coming off when attached to the eye joint main body. Also, if a first fitting portion is provided that fits into the cover plate when the cylindrical portion is attached to the cover plate to prevent the cylindrical portion from rotating relative to the cover plate, and a second fitting portion is provided that fits into the cover plate when the shaft portion is attached to the cover plate to prevent the shaft portion from rotating relative to the cover plate, rotation of the cylindrical portion and shaft portion can be prevented, which is advantageous in preventing the shaft portion from coming off the cylindrical portion when attached to the eye joint main body. Furthermore, if one of the lids has a tubular portion detachably attached to the lid plate, and the stem, lid plate of one lid, lid plate of the other lid, and connecting piece are integrally formed, it is possible to select and use a tubular portion suitable for the eye joint body and the integral stem and lid plate, which are advantageous in reducing production volume and storage space, thereby reducing costs.Furthermore, if a tubular portion locking portion that can be locked to the lid plate is formed integrally with the tubular portion at the axial end of the tubular portion, this is advantageous in preventing the tubular portion from coming off when attached to the eye joint body.Furthermore, if the configuration includes a fitting portion that fits into the tubular portion when attached to the cover plate to prevent rotation of the tubular portion relative to the cover plate, rotation of the tubular portion can be prevented, which is advantageous in preventing the shaft portion from coming off the tubular portion when attached to the eye joint main body. Furthermore, if the other cover has a detachable shaft portion attached to the cover plate, and the tubular portion, the cover plate of one cover, and the cover plate of the other cover, and the connecting piece are integrally formed, selecting and using a shaft portion suitable for the eye joint main body and the integrally formed tubular portion and cover plate can be advantageous in reducing production volume and storage space, thereby reducing costs. Furthermore, if the configuration includes a shaft locking portion that can be engaged with the cover plate at the axial end of the shaft, which is integral with the shaft, this is advantageous in preventing the shaft portion from coming off when attached to the eye joint main body. Furthermore, if the configuration includes a fitting portion that fits into the shank when it is attached to the cover plate to prevent it from rotating relative to the cover plate, rotation of the shank can be suppressed, which is advantageous in preventing the shank from coming off the tubular portion when it is attached to the eye joint main body. Furthermore, if the retaining portion is configured as the outer peripheral surface of the tubular portion and the inner peripheral surface of the shank, which detachably hold the shank inserted into the tubular portion by friction, this is advantageous in maintaining the shank inserted into the tubular portion in a detachable manner with a simple configuration. Furthermore, if the retaining portion is configured as an uneven portion provided on the inner peripheral surface of the tubular portion and the outer peripheral surface of the shank, this is advantageous in preventing the shank from coming off the tubular portion due to vibration or load.

[0011]

[0023] FIG. 1 is a perspective view of a dust cap for an eye joint according to a first embodiment;

[0024] FIG. 2 is a sectional front view of the dust cap for an eye joint according to the first embodiment;

[0025] FIG. 3 is an exploded view of the dust cap for an eye joint according to the first embodiment, where (A) is a perspective view of a pair of integrally formed cover plates and connecting pieces, (B) is a perspective view of a cylindrical portion, and (C) is a perspective view of a shaft portion;

[0026] FIG. 4 is an exploded view of the dust cap for an eye joint according to the first embodiment, where (A) is a plan view of a pair of integrally formed cover plates and connecting pieces, (B) is a plan view of a cylindrical portion, and (C) is a plan view of a shaft portion;

[0027] FIG. 4 is a sectional view showing the state in which the shaft portion has begun to be inserted into the cylindrical portion, and (B) and (C) are sectional views showing the state in which the shaft portion has been inserted into the cylindrical portion and the cover plate portion has abutted against the end surface;

[0028] FIG. 5 is an explanatory diagram of a modified example of the first embodiment;

[0029] FIG. 6 is a perspective view of a dust cap for an eye joint according to a second embodiment;

[0029] FIG. 7 is a sectional front view of a dust cap for an eye joint according to the second embodiment;

[0023] Figure 1 is an exploded view of a dust cap for an eye joint according to a second embodiment, where (A) is a perspective view of a pair of integrally formed cover plates and connecting pieces, (B) is a perspective view of a cylindrical portion, and (C) is a perspective view of a shaft portion.

[0024] Figure 2 is an exploded view of a dust cap for an eye joint according to a second embodiment, where (A) is a plan view of a pair of integrally formed cover plates and connecting pieces, (B) is a plan view of the cylindrical portion, and (C) is a plan view of the shaft portion.

[0025] Figure 3 is an exploded view of a dust cap for an eye joint according to a third embodiment, where (A) is a perspective view of a shaft portion, a pair of cover plates, and connecting pieces, and (B) is a perspective view of the cylindrical portion.

[0026] Figure 4 is an exploded view of a dust cap for an eye joint according to a fourth embodiment, where (A) is a perspective view of a shaft portion, a pair of cover plates, and connecting pieces, and (B) is a perspective view of the shaft portion. 10A and 10B are exploded views of the dust cap for the eye joint of the fifth embodiment, in which (A) is an oblique view of a pair of integrally formed cover plate portions and connecting pieces, (B) is an oblique view of the cylindrical portion, and (C) is an oblique view of the shaft portion.

[0012] (First Embodiment) An embodiment of the present invention will now be described with reference to the drawings. An eye-joint dust cap 10A according to this embodiment, as shown in Figures 1 to 4, is attached to an eye-joint fitting. First, the eye-joint fitting will be described with reference to Figure 5(A). The eye-joint fitting 50 includes a metal eye-joint body 52 and a tube 54 protruding from the eye-joint body 52.

[0013] The eye joint main body 52 is connected to, for example, a device, and the tube 54 is connected to a hose. An eyebolt insertion hole 56 is formed through the eye joint main body 52, and openings 5602 of the eyebolt insertion hole 56 are located on end surfaces 5202 on both sides of the eye joint main body 52. ​​Between the openings 5602 on both ends of the eyebolt insertion hole 56, i.e., the intermediate portion in the extending direction of the eyebolt insertion hole 56, is formed as a large-diameter portion 5604 whose inner diameter is larger than that of the openings 5602, and the large-diameter portion 5604 is in communication with a flow path 5402 of the tube 54.

[0014] The eye joint fitting 50 is arranged by connecting a hose to the tube 54, inserting an eyebolt through the eyebolt insertion hole 56, and attaching the eye joint body 52 to the mounting surface of the equipment. In this case, an annular seal member (not shown) is interposed around the shank of the eyebolt between one of the end faces 5202 on both sides and the mounting surface of the equipment, and another annular seal member (not shown) is interposed around the shank of the eyebolt between the other end face 5202 and the underside of the eyebolt head, so that the eye joint body 52 of the eye joint fitting 50 is liquid-tightly or airtightly joined to the mounting surface of the equipment. Because the end faces 5202 on both sides of the eye joint body 52 function as sealing surfaces, the end faces 5202 are protected from damage by the eye joint dust cap.

[0015] As shown in Figure 1, eye joint dust cap 10A of this embodiment is made of flexible resin or hard rubber, and includes a pair of lids 12, 14 that cover end surfaces 5202 on both sides of eye joint main body 52, and a connecting piece 16 that connects the pair of lids 12, 14. As shown in Figures 1 to 4, one lid 12 of the pair of lids 12, 14 has a lid plate 1202, a cylindrical portion 1204, and a cylindrical portion locking portion 1206. The other lid 14 of the pair of lids 12, 14 has a lid plate 1402, a shaft 1404, and a shaft portion locking portion 1406.

[0016] 3 and 4, eye joint dust cap 10A of this embodiment can be disassembled into cover plate member 1002A, which is configured by integrally forming cover plate portions 1202, 1402 and connecting piece 16 connecting them, cylindrical member 1004A, which is configured by cylindrical portion 1204 and cylindrical portion locking portion 1206, and shaft member 1006A, which is configured by shaft portion 1404 and shaft portion locking portion 1406. Therefore, in this embodiment, cylindrical portion 1204 is detachably provided on cover plate portion 1202 of one cover portion 12, and shaft portion 1404 is detachably provided on cover plate portion 1402 of the other cover portion 14.

[0017] The cover plate 1202 of one of the lids 12 is formed in the shape of a ring plate with a uniform thickness large enough to cover one of the end faces 5202 on both sides of the eye joint body 52. ​​As shown in Figures 3 and 4, a tubular portion insertion hole 1202A is provided in the center of the cover plate 1202, allowing the insertion of the tubular portion 1204. The inner diameter of the tubular portion insertion hole 1202A is formed slightly larger than the outer diameter of the tubular portion 1204, allowing the tubular portion 1204 to be inserted.

[0018] 1, the tube portion 1204 is inserted into the tube portion insertion hole 1202A during use and protrudes from the center of the cover plate portion 1202. The tube portion 1204 is formed in a cylindrical shape having an outer peripheral surface with a uniform outer diameter that is smaller than the inner diameter of the opening 5602 of the end face portion 5202 of the eye joint main body 52, and an inner peripheral surface with a uniform inner diameter. As shown in FIGS. 5(B) and (C), the height of the tube portion 1204 from the tube portion locking portion 1206 is formed to be slightly smaller than the combined dimension between the end faces 5202 on both sides of the eye joint main body 52 and the thickness of the two cover plates 1202, 1402. As shown in FIG. 2, the tip of the inner peripheral surface of the tube portion 1204 is formed with an inclined surface 1204A whose inner diameter gradually decreases as it approaches the tube portion locking portion 1206, thereby facilitating the smooth insertion of the shaft portion 1404, which will be described later.

[0019] The cylindrical portion locking portion 1206 is formed in a circular shape with a uniform thickness and an outer diameter larger than the inner diameter of the cylindrical portion insertion hole 1202A, and is provided integrally with the cylindrical portion 1204 at the end of the cylindrical portion 1204 in the axial direction. When the cylindrical portion 1204 is inserted into the cylindrical portion insertion hole 1202A of the cover plate portion 1202, the cylindrical portion locking portion 1206 can be locked to a portion of the cover plate portion 1202 around the cylindrical portion insertion hole 1202A. This locks the cylindrical member 1004A to the cover plate member 1002A.

[0020] The cover plate portion 1402 of the other cover portion 14 is formed in the shape of a ring plate with a uniform thickness large enough to cover the other of the end face portions 5202 on both sides of the eye joint main body 52, and is formed with the same thickness and outer diameter as the cover plate portion 1202 from which the cylindrical portion 1204 protrudes. As shown in Figures 3 and 4, a shaft insertion hole 1402A is provided in the center of the cover plate portion 1402, allowing the shaft portion 1404 to be inserted therethrough. The inner diameter of the shaft insertion hole 1402A is formed slightly larger than the outer diameter of the shaft portion 1404, allowing the shaft portion 1404 to be inserted therethrough.

[0021] In this embodiment, the shaft portion 1404 is cylindrical and formed with a uniform inner diameter and a uniform outer diameter. As shown in FIG. 1 , the cylindrical shaft portion 1404 is inserted into the shaft portion insertion hole 1402A during use and protrudes from the center of the cover plate portion 1402, and has an outer peripheral surface that is releasably inserted into the inner peripheral surface of the tube portion 1204. In other words, the cylindrical shaft portion 1404 is provided so as to be releasably fitted inside the tube portion 1204. Specifically, the outer diameter of the shaft portion 1404 is formed to be slightly larger than the inner diameter of the tube portion 1204.

[0022] 5(B) and (C), the height of the shaft portion 1404 from the shaft portion locking portion 1406 is slightly smaller than the combined dimension between the end surface portions 5202 on both sides of the eye joint main body 52 and the thickness of the two cover plates 1202, 1402. In this embodiment, the height of the shaft portion 1404 is formed to be the same dimension as the height of the tubular portion 1204 from the tubular portion locking portion 1206, ensuring a large contact area between the inner peripheral surface of the tubular portion 1204 and the outer peripheral surface of the shaft portion 1404, which is advantageous for stably maintaining protection of the end surface portions 5202 on both sides by the cover plates 1202, 1402, as described below. As shown in FIG. 2, the tip of the outer peripheral surface of the cylindrical shaft portion 1404 is formed with an inclined surface 1404A whose outer diameter gradually decreases toward the tip, thereby facilitating smooth insertion into the tubular portion 1204. Although the shaft portion 1404 may be formed in a solid shape, forming it in a cylindrical shape as in this embodiment is advantageous in terms of reducing the weight.

[0023] The shaft locking portion 1406 is formed in a circular shape with a uniform thickness that is larger than the inner diameter of the shaft insertion hole 1402A, and is provided integrally with the shaft 1404 at the end of the shaft 1404 in the axial direction. When the shaft 1404 is inserted into the shaft insertion hole 1402A of the cover plate 1402, the shaft locking portion 1406 can be locked to a portion of the cover plate 1402 around the shaft insertion hole 1402A. This locks the shaft member 1006A to the cover plate member 1002A.

[0024] Eye joint dust cap 10A is provided with retaining portion 18 that detachably holds shaft portion 1404 inserted into cylindrical portion 1204. In this embodiment, the inserted state of shaft portion 1404 is maintained in cylindrical portion 1204 by friction between the inner peripheral surface of cylindrical portion 1204 and the outer peripheral surface of shaft portion 1404. Therefore, retaining portion 18 in this embodiment is the inner peripheral surface of cylindrical portion 1204 and the outer peripheral surface of shaft portion 1404.

[0025] The connecting piece 16 connects the cover plate 1202 and the cover plate 1402 of the pair of covers 12, 14, and is elongated and flexible. Although the connecting piece 16 may be omitted, providing the connecting piece 16 prevents the loss of the cover plate 1202, 1402 that would otherwise be separated, i.e., the loss of the eye-joint dust cap 10A, and is advantageous in improving handleability. The shape of the connecting piece 16 may be rod-like or the like, and is not limited to a thin plate shape as in the embodiment. In short, it is sufficient that the connecting piece 16 is flexible, and the cross-sectional shape is arbitrary.

[0026] Next, a method of using the eye joint dust cap 10A of this embodiment will be described. When using the eye joint dust cap 10A, first, the cylindrical portion 1204 is inserted into the cylindrical portion insertion hole 1202A of the cover plate 1202, and the cylindrical portion locking portion 1206 is locked to the cover plate 1202. At the same time, the shank 1404 is inserted into the shank insertion hole 1402A of the cover plate 1402, and the shank locking portion 1406 is locked to the cover plate 1402. Next, as shown in FIGS. 5A and 5B , the connecting piece 16 is bent to position the pair of covers 12, 14 opposite each other over the eyebolt insertion hole 56, and the cylindrical shank 1404 is inserted inside the cylindrical portion 1204, and the cover plates 1202, 1402 of the pair of covers 12, 14 are brought into contact with the end surfaces 5202 on both sides of the eye joint body 52. The state in which the cover plate portions 1202, 1402 of this pair of cover portions 12, 14 are abutted against the end face portions 5202 on both sides of the eye joint main body 52 is maintained by friction between the inner surface of the tubular portion 1204, which is the holding portion 18, and the outer surface of the shaft portion 1404.

[0027] Furthermore, when removing the pair of lids 12, 14 from the eye joint body 52, the lid plate 1402 is grasped and the shaft 1404 is pulled out from the tubular portion 1204. After removing them from the eye joint body 52, the tubular portion 1204 is pulled out from the tubular portion insertion hole 1202A of the lid plate 1202, and the shaft 1404 is pulled out from the shaft portion insertion hole 1402A of the lid plate 1402.

[0028] According to eye joint dust cap 10A of this embodiment, tubular portion 1204 and shaft portion 1404 are detachably attached to cover plate portions 1202, 1402. Therefore, eye joint dust cap 10A can be used to accommodate a variety of eye joint fittings 50 by combining parts (cover plate portions 1202, 1402) that match the size of end face portion 5202 of eye joint main body 52, and parts (tubular portion 1204, shaft portion 1404) that match the axial thickness of eye joint main body 52 and the inner diameter of eye bolt insertion hole 56. This eliminates the need to manufacture eye joint dust caps each time for a variety of eye joint fittings 50, which is advantageous for reducing the cost of eye joint dust caps by reducing production volume and storage space. Furthermore, since the retaining portion 18 is configured to be the outer peripheral surface of the tubular portion 1204 and the inner peripheral surface of the shaft portion 1404, which detachably hold the shaft portion 1404 inserted into the tubular portion 1204 by friction, it is advantageous for detachably holding the shaft portion 1404 inserted into the tubular portion 1204 with a simple configuration. Furthermore, since the tubular portion 1204 and the shaft portion 1404 are detachably provided to the cover plates 1202, 1402 of one lid portion 12 and the other lid portion 14, and the cover plate 1202 of one lid portion 12 and the cover plate 1402 of the other lid portion 14 are configured to be integral with the connecting piece 16, it is possible to select and combine the tubular portion 1204, the shaft portion 1404, and the cover plates 1202, 1402 that are suitable for the eye joint main body 52, which is advantageous for reducing production volume and storage space, thereby reducing costs.

[0029] A more detailed explanation follows. As shown in FIG. 5C , if the cover plates 1202 and 1402 are formed larger than the end surface 5202 of the eye joint main body 52, different sizes of the end surface 5202 of the eye joint main body 52 can be accommodated. Furthermore, if the axial thickness of the eye joint main body 52 is too large for the first embodiment, the following can be done. As shown in FIG. 6A , a cover plate member 1002A having the same shape as that of the first embodiment is prepared, in which the cover plates 1202 and 1402 and the connecting piece 16 connecting them are integrally formed. Then, a cylindrical member 1004A having a cylindrical portion 1204 with a large height from the cylindrical portion locking portion 1206 and a shaft member 1006A having a shaft portion 1404 with a large height from the shaft portion locking portion 1406 are selected.

[0030] Furthermore, if the axial thickness of the eye joint main body 52 is slightly too large for the first embodiment, the following solution is possible. For example, one of the tubular portion 1204 and the shank 1404 of the first embodiment shown in FIG. 2 can be integrally formed with the cover plate 1202. Then, for example, the other of the tubular portion 1204 and the shank 1404 can be replaced with a taller shank member 1006A shown in FIG. 6A and inserted into the shank insertion hole 1402A of the cover plate 1402. In other words, even if at least one of the tubular portion 1204 and the shank 1404 is detachably formed on the cover plates 1202 and 1402, it is not necessary to manufacture a separate eye joint dust cap for each eye joint fitting 50 of a different size, which is advantageous for reducing costs.

[0031] Furthermore, if the axial thickness of the eye joint main body 52 is small and the inner diameter of the eyebolt insertion hole 56 is small and therefore the first embodiment described above cannot be used, the following solution can be used. As shown in Figure 6(B), a cover plate member 1002A of the same shape as that of the first embodiment is prepared, in which the cover plate portions 1202, 1402 and the connecting piece 16 connecting them are integrally formed. Then, a tubular member 1004A having a tubular portion 1204 with a small height from the tubular portion locking portion 1206, a small outer diameter, and a small inner diameter, and a shaft member 1006A having a shank portion 1404 with a small height from the shank locking portion 1406 and a small outer diameter, can be selected. In this case, a flange 1207 is provided at the end of the tube portion 1204 on the tube portion engaging portion 1206 side, the flange 1207 being slightly larger than the inner diameter of the tube portion insertion hole 1202A of one of the cover plates 1202 and removably insertable into the tube portion insertion hole 1202A, with the same thickness as one of the cover plates 1202; and a flange 1407 is provided at the end of the shaft portion 1404 on the shaft portion engaging portion 1406 side, the flange 1407 being slightly larger than the shaft portion insertion hole 1402A of the other cover plate 1402 and removably insertable into the shaft portion insertion hole 1402A, with the same thickness as the other cover plate 1402. Then, at the end of flange 1207 opposite cylindrical portion 1204, cylindrical portion locking portion 1206 capable of locking with cover plate 1202 may be provided integrally with flange 1207, and at the end of flange 1407 opposite shaft portion 1404, shaft portion locking portion 1406 capable of locking with cover plate 1402 may be provided integrally with flange 1407. Therefore, for example, if a plurality of cover plate members 1002A of the same shape are prepared and a plurality of different types of cylindrical members 1004A and shaft members 1006A of different shapes are prepared, eye joint fittings 50 of different sizes can be accommodated by appropriately selecting cylindrical members 1004A and shaft members 1006A, eliminating the need to manufacture an eye joint dust cap for each different sized eye joint fitting 50, which is advantageous for reducing costs.

[0032] Second Embodiment In the first embodiment, the inserted state of shaft portion 1404 in cylindrical portion 1204 is maintained by friction between the inner peripheral surface of cylindrical portion 1204 and the outer peripheral surface of shaft portion 1404, whereas in the second embodiment, the inserted state of shaft portion 1404 in the cylindrical portion is maintained in a detachable manner by uneven portions provided on the inner peripheral surface of the cylindrical portion and the outer peripheral surface of the shaft portion. Note that in the following description of the embodiment, the same parts and members as in the first embodiment are denoted by the same reference numerals and their description will be omitted, and the description will focus on the parts that are different from the first embodiment.

[0033] An eye joint dust cap 10B of this embodiment will be described with reference to Figures 7 to 10. As shown in Figures 9 and 10, the eye joint dust cap 10B can be disassembled into a cover plate member 1002B, which is configured by integrally forming cover plates 1208, 1408 and a connecting piece 16 connecting them; a cylindrical member 1004B, which is configured by a cylindrical portion 1210 and a cylindrical portion locking portion 1206; and a shaft member 1006B, which is configured by a shaft portion 1410 and a shaft portion locking portion 1406. Therefore, in this embodiment, the cylindrical portion 1210 is detachably attached to the cover plate 1208 of one cover 12, and the shaft portion 1410 is detachably attached to the cover plate 1408 of the other cover 14.

[0034] In this embodiment, one of the lids 12 is provided with a first fitting portion 20 that fits into the inner periphery of the tubular portion insertion hole 1208A of the cover plate 1208 and the end of the outer periphery of the tubular portion 1210 on the tubular portion locking portion 1206 side when the tubular portion 1210 is attached to the cover plate 1208, preventing the tubular portion 1210 from rotating relative to the cover plate 1208. Specifically, the first fitting portion 20 is composed of a fitting recess 1208B provided in the cover plate 1208 and a fitting protrusion 1210B provided in the tubular portion 1210 that fits into the fitting recess 1208B. The fitting recess 1208B is formed in a rectangular shape on the inner periphery of the tubular portion insertion hole 1208A, on an extension of the connecting piece 16 and closer to the connecting piece 16. The fitting protrusion 1210B is a protrusion having a rectangular cross section, and is provided on the outer peripheral surface of the cylindrical portion 1210 and on the upper surface of the cylindrical portion locking portion 1206.

[0035] In the present embodiment, the other lid 14 is provided with a second fitting portion 22 that fits into the inner periphery of the shaft insertion hole 1408A of the cover plate 1408 and the end of the outer periphery of the shaft 1410 on the shaft locking portion 1406 side when the shaft 1410 is attached to the cover plate 1408, preventing the shaft 1410 from rotating relative to the cover plate 1408. Specifically, the second fitting portion 22 is composed of a fitting recess 1408B provided in the cover plate 1408 and a fitting protrusion 1410B provided in the shaft 1410 that fits into the fitting recess 1408B. The fitting recess 1408B is formed in a rectangular shape on the inner periphery of the shaft insertion hole 1408A, on an extension of the connecting piece 16 and closer to the connecting piece 16. The fitting protrusion 1410B is a protrusion having a rectangular cross section, and is provided on the outer peripheral surface of the shaft portion 1410 and on the upper surface of the shaft portion locking portion 1406.

[0036] Eye joint dust cap 10B is provided with holding portion 18 that detachably holds shaft portion 1410 inserted into tubular portion 1210. In this embodiment, uneven portions 26 that constitute holding portion 18 are provided on the inner circumferential surface of tubular portion 1210 and the outer circumferential surface of shank 1410.

[0037] The uneven portion 26 provided on the inner peripheral surface of the cylindrical portion 1210 is composed of a plurality of inner peripheral surface convex portions 1210C that protrude from the inner peripheral surface, extend in the circumferential direction of the inner peripheral surface, and are arranged at equal intervals in the axial direction of the cylindrical portion 1210. In this embodiment, as shown in FIGS. 7 to 10 , the inner peripheral surface convex portions 1210C, each having a sawtooth cross section, are configured to be shorter than the entire circumferential circumference of the inner peripheral surface of the cylindrical portion 1210, and are arranged in plurality from one end to the other end in the axial direction of the cylindrical portion 1210. In addition, the inner peripheral surface of the cylindrical portion 1210 is provided with inner peripheral surface retracted portions 1210D formed by cutting out the inner peripheral surface convex portions 1210C in the circumferential and axial directions.

[0038] In this embodiment, the inner peripheral surface convex portions 1210C and the inner peripheral surface retracted portions 1210D are provided in two locations and each extend a length that is ¼ of the entire circumference of the inner peripheral surface of the cylindrical portion 1210. In other words, the inner peripheral surface of the cylindrical portion 1210 is configured such that two inner peripheral surface convex portions 1210C and two inner peripheral surface retracted portions 1210D, each with a central angle of 90°, are alternately arranged.

[0039] The uneven portion 26 provided on the outer peripheral surface of the shaft portion 1410 is an outer peripheral surface side protrusion 1410C that protrudes from the outer peripheral surface, extends in the circumferential direction of the outer peripheral surface, and is configured as a plurality of outer peripheral surface side protrusions 1410C arranged at equal intervals in the axial direction of the shaft portion 1410, and can be engaged with and disengaged from the inner peripheral surface side protrusions 1210C. In this embodiment, as shown in FIGS. 7 to 10 , the outer peripheral surface side protrusions 1410C, each having a sawtooth cross section, are configured to be shorter than the entire circumferential circumference of the outer peripheral surface of the shaft portion 1410, and are configured as a plurality of protrusions arranged from one end to the other end in the axial direction of the shaft portion 1410. In addition, the outer peripheral surface of the shaft portion 1410 is provided with an outer peripheral surface side retraction portion 1410D, in which the outer peripheral surface side protrusion 1410C is cut away in the circumferential and axial directions.

[0040] In this embodiment, outer peripheral surface side convex portions 1410C and outer peripheral surface side retracted portions 1410D are provided in two locations and each extend a length that is one-fourth of the entire circumference of the outer peripheral surface of shaft portion 1410. In other words, outer peripheral surface side convex portions 1410C and outer peripheral surface side retracted portions 1410D, each having a central angle of 90°, are arranged alternately in pairs on the outer peripheral surface of shaft portion 1410.

[0041] The outer diameter of the tip of outer peripheral surface side convex portion 1410C protruding from the outer peripheral surface of shaft portion 1410 is slightly larger than the inner diameter of the tip of inner peripheral surface side convex portion 1210C protruding from the inner peripheral surface of tubular portion 1210. Therefore, when shank portion 1410 is inserted into tubular portion 1210, concave-convex portions 26 provided on the inner peripheral surface of tubular portion 1210 and the outer peripheral surface of shank portion 1410 are releasably coupled, that is, inner peripheral surface side convex portion 1210C and outer peripheral surface side convex portion 1410C are fitted together and coupled, maintaining the state in which shank portion 1410 is inserted into tubular portion 1210.

[0042] Furthermore, in this embodiment, when the shaft portion 1410 is inserted into the tubular portion 1210, the inner surface side convex portion 1210C and the outer surface side convex portion 1410C face each other in the radial direction of the tubular portion 1210, and the inner surface side retraction portion 1210D and the outer surface side retraction portion 1410D are in opposing positions, the inner surface side convex portion 1210C and the outer surface side convex portion 1410C are coupled, thereby maintaining the shaft portion 1410 inserted into the tubular portion 1210.

[0043] On the other hand, in the present embodiment, with the shaft portion 1410 inserted into the tubular portion 1210, the inner peripheral surface retracted portion 1210D and the outer peripheral surface convex portion 1410C face each other in the radial direction of the tubular portion 1210, and when the outer peripheral surface retracted portion 1410D and the inner peripheral surface convex portion 1210C are in a position where they face each other, the shaft portion 1410 is movable in the axial direction of the tubular portion 1210. In other words, the shaft portion 1410 can be easily inserted into the tubular portion 1210 and the tubular portion 1210 can be easily removed from the tubular portion 1210.

[0044] The inner surface side convex portion 1210C and the outer surface side convex portion 1410C are not limited to having a sawtooth-shaped cross section as in this embodiment, and may have a V-shaped or hemispherical cross section extending circumferentially, for example. However, if they are formed into a sawtooth shape that is inclined toward the cover plate portions 1208 and 1408 as in this embodiment, this is advantageous in terms of making it easy to insert the shaft portion 1410 into the tube portion 1210 and difficult to remove.

[0045] Furthermore, the uneven portion 26 is not limited to extending circumferentially as in this embodiment, and various conventionally known engagement and disengagement structures can be adopted, such as a structure in which hemispherically protruding convex portions and hemispherically recessed concave portions are scattered.

[0046] Next, a method of using eye joint dust cap 10B of this embodiment will be described. When using eye joint dust cap 10B, first, tube portion 1210 is inserted into tube portion insertion hole 1208A of cover plate 1208, and tube portion locking portion 1206 is locked to cover plate 1208. At the same time, shaft portion 1410 is inserted into shaft portion insertion hole 1408A of cover plate 1408, and shaft portion locking portion 1406 is locked to cover plate 1408. At this time, mating protrusion 1210B on tube portion 1210 is mated with mating recess 1208B on cover plate 1208, and mating protrusion 1410B on shaft portion 1410 is mated with mating recess 1408B on cover plate 1408. Next, as shown in Figures 5 (A) and (B), the connecting piece 16 is bent to position the pair of lid portions 12, 14 facing each other on the eyebolt insertion hole 56, and then both or either of the pair of lid portions 12, 14 is rotated so that the inner surface side recessed portion 1210D faces the outer surface side protrusion portion 1410C and the outer surface side recessed portion 1410D faces the inner surface side protrusion portion 1210C. Then, the cylindrical shaft portion 1410 is pushed and inserted into the inside of the tubular portion 1210, and the lid plate portions 1208, 1408 of the pair of lid portions 12, 14 abut against the end surface portions 5202 on both sides of the eye joint main body 52.

[0047] Then, when one of the pair of lids 12, 14 is rotated while the cover plates 1208, 1408 of the pair of lids 12, 14 are in contact with the end surfaces 5202 on both sides of the eye joint body 52, the inner circumferential surface convex portion 1210C and the outer circumferential surface convex portion 1410C are mated. After being rotated 90 degrees, the entire inner circumferential surface convex portion 1210C and the entire outer circumferential surface convex portion 1410C are mated, and the inner circumferential surface retracted portion 1210D and the outer circumferential surface retracted portion 1410D face each other. The entire inner circumferential surface convex portion 1210C and the entire outer circumferential surface convex portion 1410C are mated, thereby maintaining the cover plates 1208, 1408 of the pair of lids 12, 14 in contact with the end surfaces 5202 on both sides of the eye joint body 52. In this state, the connecting piece 16 is curved without being twisted, as shown in FIG. 5(B).

[0048] Furthermore, when removing the pair of lid portions 12, 14 from the eye joint main body 52, one of the pair of lid portions 12, 14 is rotated 90° so that the inner surface side retraction portion 1210D faces the outer surface side protrusion portion 1410C and the outer surface side retraction portion 1410D faces the inner surface side protrusion portion 1210C, and then the lid plate portion 1408 is grasped and the shaft portion 1410 is pulled out from the tubular portion 1210.

[0049] 11 , in order to facilitate the removal of the shank 1410 from the tube portion 1210, a configuration may be adopted in which a tube portion-side grip 28 is provided on the surface of the tube portion locking portion 1206 opposite the surface from which the tube portion 1210 protrudes, and a shank portion-side grip 30 is provided on the surface of the shank locking portion 1406 opposite the surface from which the shank 1410 protrudes, as shown in FIG. 11 . In this embodiment, the tube portion locking portion 1206 and the shank locking portion 1406 are formed in a circular shape as described above, and the tube portion-side grip 28 and the shank portion-side grip 30 are provided extending on the diameters of the tube portion locking portion 1206 and the shank locking portion 1406, respectively, and have concave side surfaces 2802 and 3002 formed to allow the operator's fingers to hook thereon.

[0050] Furthermore, one of the barrel-side gripping portion 28 and the shank-side gripping portion 30 is provided to extend in the same direction as the connecting piece 16, and the other gripping portion is provided to be perpendicular to the connecting piece 16. In this embodiment, one gripping portion is the shank-side gripping portion 30, and the other gripping portion is the barrel-side gripping portion 28. Providing the barrel-side gripping portion 28 and the shank-side gripping portion 30 in this manner facilitates the rotational operation of the pair of lids 12, 14, which is advantageous for facilitating the removal of the shank 1410 from the barrel 1210. Furthermore, in this embodiment, because the barrel-side gripping portion 28 is provided perpendicular to the shank-side gripping portion 30 and the connecting piece 16, rotating the barrel-side gripping portion 28 until it is in the same direction as the extension direction of the shank-side gripping portion 30 corresponds to a 90° rotation, which is advantageous for grasping the rotation angle of the barrel-side gripping portion 28.

[0051] In this embodiment, the tube portion locking portion 1206 and the shaft portion locking portion 1406 are configured to have a tube portion side grip portion 28 and a shaft portion side grip portion 30, but various types of operating members with conventionally known structures can be used, such as providing an operating piece that extends linearly from the outer periphery of the tube portion locking portion 1206 and the shaft portion locking portion 1406.

[0052] Eye joint dust cap 10B of this embodiment provides the same effects as those of Embodiment 1. Furthermore, retaining portion 18 is configured as uneven portions 26 (inner peripheral surface-side convex portion 1210C and outer peripheral surface-side convex portion 1410C) provided on the inner peripheral surface of tubular portion 1210 and the outer peripheral surface of shaft portion 1410, which is advantageous in preventing shaft portion 1410 from coming off from tubular portion 1210 due to vibration or load. Furthermore, a first fitting portion 20 is provided that engages with the tubular portion 1210 when it is attached to the cover plate portion 1208, preventing the tubular portion 1210 from rotating relative to the cover plate portion 1208, and a second fitting portion 22 is provided that engages with the shank portion 1410 when it is attached to the cover plate portion 1408, preventing the shank portion 1410 from rotating relative to the cover plate portion 1408. This configuration prevents the rotation of the tubular portion 1210 and the shank portion 1410, which is advantageous in preventing the shank portion 1410 from coming loose from the tubular portion 1210 when it is attached to the eye joint main body 52.

[0053] In the second embodiment described above, the inner peripheral surface convex portions 1210C are arranged continuously from one end to the other end of the tubular portion 1210, and the outer peripheral surface convex portions 1410C are arranged continuously from one end to the other end of the shaft portion 1410. However, the inner peripheral surface convex portions and the outer peripheral surface convex portions may be arranged discontinuously as long as they fit together. However, if they are arranged continuously, the insertion of the shaft portion 1404 into the tubular portion 1204 can be adjusted to match the thickness of the eye joint main body 52. ​​Furthermore, the inner peripheral surface convex portions 1210C of the tubular portion 1210 may be provided only at the tip of the tubular portion 1210, or the outer peripheral surface convex portions 1410C of the shaft portion 1410 may be provided only at the tip of the shaft portion 1410. This simplifies the configuration and is advantageous for easily manufacturing the eye joint dust cap 10B.

[0054] In the second embodiment, the cylindrical portion 1210 and the shaft portion 1410 are divided into four sections, with the convex portions (inner peripheral surface convex portion 1210C, outer peripheral surface convex portion 1410C) and the recessed portions (inner peripheral surface recessed portion 1210D, outer peripheral surface recessed portion 1410D) arranged alternately. However, the number of divisions is arbitrary. Therefore, for example, the convex portions and the recessed portions can be arranged alternately by dividing them into two (180°), six (60°), eight (45°), ten (36°), or twelve (30°) divisions, or any other desired ratio. Note that the greater the number of divisions, the easier it is to insert the shaft portion 1410 into the cylindrical portion 1210 but the easier it is to remove it. Conversely, the fewer the number of divisions, the harder it is to insert the shaft portion 1410 into the cylindrical portion 1210 but the harder it is to remove it.

[0055] In the second embodiment, the shaft 1410 is detachably attached to the cover plate 1408 of the other cover 14. However, in this embodiment, the shaft and cover plate are integrally formed. An eye-joint dust cap 10C of this embodiment will be described with reference to FIG. 12 .

[0056] 12, the eye joint dust cap 10C can be disassembled into a cover plate shaft member 1008C that is configured by integrally forming a shaft portion 1410, cover plates 1208, 1412, and a connecting piece 16 that connects them, and a cylindrical member 1004B that is configured by a cylindrical portion 1210 and a cylindrical portion locking portion 1206. Therefore, in this embodiment, in one cover 12, the cylindrical portion 1210 is detachably provided on the cover plate 1208, and in the other cover 14, the shaft portion 1410 and cover plate 1412 are integrally formed.

[0057] The cover plate 1412 is formed in a circular shape with a uniform thickness and a size sufficient to cover the other of the end surface portions 5202 on both sides of the eye joint main body 52. ​​The shape of the shaft 1410 is the same as in the second embodiment, but the shaft 1410 in this embodiment protrudes from the center of the cover plate 1412 and is formed integrally with the cover plate 1412. In this embodiment, since the shaft 1410 is provided on the cover plate 1412, the shaft locking portion 1406 is not provided.

[0058] The eye joint dust cap 10C of this embodiment has the same effects as the second embodiment. In addition, in the other lid portion 14, the shaft portion 1410 is formed integrally with the lid plate portion 1412, so the eye joint dust cap 10C is made up of only two parts, which is advantageous in preventing loss.

[0059] In the third embodiment, the cylindrical portion 1210 is detachably attached to the cover plate 1208 of one of the lids 12. However, in this embodiment, the cylindrical portion and the cover plate are integrally formed. An eye-joint dust cap 10D of this embodiment will be described with reference to FIG. 13 .

[0060] 13, the eye joint dust cap 10D can be disassembled into a cover plate cylindrical member 1010D which is configured by integrally providing a cylindrical portion 1210, cover plates 1212 and 1408, and a connecting piece 16 which connects them, and a shaft member 1006B which is configured by a shaft portion 1410 and a shaft locking portion 1406. Therefore, in this embodiment, the shaft portion 1410 is detachably provided on the cover plate 1408 in the other cover 14, and the cylindrical portion 1210 and cover plate 1212 are integrally formed in one cover 12.

[0061] The cover plate portion 1212 is formed in a circular shape with a uniform thickness and a size that covers one of the end surface portions 5202 on both sides of the eye joint main body 52. ​​The shape of the tubular portion 1210 is the same as in the second embodiment, but the tubular portion 1210 in this embodiment protrudes from the center of the lid plate portion 1212 and is formed integrally with the lid plate portion 1212. In this embodiment, since the tubular portion 1210 is provided on the lid plate portion 1212, the tubular portion locking portion 1206 is not provided.

[0062] Eye joint dust cap 10D of this embodiment provides the same effects as those of embodiment 3. In addition, in one of lid portions 12, cylindrical portion 1210 is formed integrally with lid plate portion 1212, so eye joint dust cap 10D is made up of only two parts, which is advantageous in preventing loss.

[0063] Fifth Embodiment In the second embodiment, the cylindrical portion 1210 and the shaft portion 1410 are formed in a cylindrical shape, but they may also be configured to have slits. An eye-joint dust cap 10E of this embodiment will be described with reference to FIG.

[0064] In this embodiment, as in the second embodiment, the shaft portion 1410 is configured such that outer peripheral surface side convex portions 1410C and outer peripheral surface side retracted portions 1410D, each of which is one-quarter of the circumference of the shaft portion 1410, are arranged alternately, and each of the two outer peripheral surface side retracted portions 1410D is provided with a shaft portion side slit 32. The shaft portion side slit 32 is provided at the circumferential center of the outer peripheral surface side retracted portion 1410D, extending in the protruding direction of the shaft portion 1410 and opening at the tip in the protruding direction. This allows deformation of the shaft portion 1410 radially inward when the shaft portion 1410 is inserted into or extracted from the cylindrical portion 1210, thereby facilitating coupling and release between the inner peripheral surface side convex portion 1210C (concave-convex portion 26) of the cylindrical portion 1210 and the outer peripheral surface side convex portion 1410C (concave-convex portion 26) of the shaft portion 1410.

[0065] 14, slits are provided in the shaft portion 1410, but slits may also be provided in the tube portion 1210 (not shown). That is, as in the second embodiment, the tube portion 1210 is configured such that inner circumferential surface side convex portions 1210C and inner circumferential surface side retracted portions 1210D, each of which is obtained by dividing the entire circumference into four, are alternately arranged, and a tube portion side slit may be provided in each of the two inner circumferential surface side retracted portions 1210D. Like the shaft portion side slit 32, the tube portion side slit is located in the circumferential center of the inner surface side retreat portion 1210D, extending in the protruding direction of the tube portion 1210 and opening at the tip in the protruding direction, which allows the tube portion 1210 to deform radially outward when the shaft portion 1410 is inserted into or removed from the tube portion 1210, thereby making it easy to couple and unclip the inner surface side convex portion 1210C (uneven portion 26) of the tube portion 1210 and the outer surface side convex portion 1410C (uneven portion 26) of the shaft portion 1410.

[0066] The dust cap 10E for eye joint of this embodiment achieves the same effects as the second embodiment, and also makes it easier to couple and release the inner surface convex portion 1210C of the tubular portion 1210 and the outer surface convex portion 1410C of the shaft portion 1410, which is advantageous in facilitating insertion and removal of the shaft portion 1410 from the tubular portion 1210.

[0067] 10A, 10B, 10C, 10D, 10E Dust cap for eye joint 1002A, 1002B Cover plate member 1004A, 1004B Cylindrical member 1006A, 1006B Shaft member 1008C Cover plate shaft member 1010D Cover plate cylindrical member 12, 14 Cover portion 1202, 1208, 1212, 1402, 1408, 1412 Cover plate portion 1202A, 1208A Insertion hole for cylindrical portion 1204, 1210 Cylindrical portion 1206 Locking portion for cylindrical portion 1207 Flange portion 1208B Fitting recess 1210B Fitting protrusion 1210C Inner peripheral surface side protrusion 1210D Inner peripheral surface side retraction portion 1402A, 1408A Shaft insertion hole 1404, 1410 Shaft 1406 Shaft locking portion 1407 Flange portion 1408B Fitting recess 1410B Fitting protrusion 1410C Outer peripheral surface side protrusion 1410D Outer peripheral surface side retraction portion 16 Connection piece 18 Holding portion 26 Concave and recessed portion 28 Cylinder portion side gripping portion 30 Shaft portion side gripping portion 32 Shaft portion side slit 50 Eye joint fitting 52 Eye joint main body 5202 End surface portion 54 Tube body 56 Eyebolt insertion hole 5602 Opening 5604 Large diameter portion

Claims

1. A dust cap for an eye joint comprising: a pair of lids covering both end faces of an eye joint body having an opening for an eyebolt insertion hole; and a connecting piece connecting the pair of lids, one of the pair of lids having a cover plate covering the end face and a tubular portion protruding from the cover plate and having an inner circumferential surface and an outer peripheral surface with an outer diameter smaller than the inner diameter of the opening, the other of the pair of lids having a cover plate covering the end face and a shaft portion protruding from the cover plate and having an outer circumferential surface inserted into the inner circumferential surface of the tubular portion, and provided with a retaining portion for releasably holding the shaft portion inserted into the tubular portion, and at least one of the tubular portion and the shaft portion being releasably provided on the cover plate.

2. A dust cap for an eye joint as described in claim 1, characterized in that in said one lid part and the other lid part, the tubular part and the shaft part are detachably attached to the cover plate part, the cover plate part of said one lid part has a shaft part insertion hole to allow the tubular part to be inserted therethrough, the tubular part is formed integrally with the tubular part at an end in the axial direction of the tubular part and has a shaft part locking part that can be engaged with a portion of the cover plate part around the shaft part insertion hole, the cover plate part of the other lid part has a shaft part insertion hole to allow the shaft part to be inserted therethrough, the shaft part is formed integrally with the shaft part at an end in the axial direction of the shaft part and has a shaft part locking part that can be engaged with a portion of the cover plate part around the shaft part insertion hole, and the cover plate part of said one lid part, the cover plate part of said other lid part and the connecting piece are formed integrally.

3. A dust cap for an eye joint as described in claim 2, characterized in that a first fitting portion is provided on an inner periphery of the tube portion insertion hole of the cover plate and on an end of the outer periphery of the tube portion facing the tube portion locking portion when the tube portion is attached to the cover plate, preventing the tube portion from rotating relative to the cover plate, and a second fitting portion is provided on an inner periphery of the shaft portion insertion hole of the cover plate and on an end of the outer periphery of the shaft portion facing the shaft locking portion when the shaft portion is attached to the cover plate, preventing the shaft portion from rotating relative to the cover plate.

4. A dust cap for an eye joint as described in claim 1, characterized in that, in one of the lid parts, the tubular part is detachably attached to the cover plate part, the cover plate part of the one of the lid parts is provided with a tubular part insertion hole allowing the tubular part to be inserted, the tubular part has a tubular part engaging part which is formed integrally with the tubular part at an end in the axial direction of the tubular part and can engage with a location of the cover plate part around the tubular part insertion hole, and the shaft part, the cover plate part of the one of the lid parts, the cover plate part of the other lid part and the connecting piece are formed integrally.

5. A dust cap for an eye joint as described in claim 4, characterized in that an engaging portion is provided on the inner periphery of the tubular portion insertion hole of the cover plate and on the end of the outer periphery of the tubular portion on the side of the tubular portion locking portion, which engages with the tubular portion when the tubular portion is attached to the cover plate, preventing the tubular portion from rotating relative to the cover plate.

6. A dust cap for an eye joint as described in claim 1, characterized in that in the other lid part, the shaft is detachably attached to the cover plate, the cover plate part of the other lid part has a shaft insertion hole allowing the shaft to be inserted, the shaft is integrally formed at the axial end of the shaft and has a shaft locking part that can be locked to a location of the cover plate around the shaft insertion hole, and the tube part, the cover plate part of one of the lid parts, the cover plate part of the other lid part and the connecting piece are integrally formed.

7. A dust cap for an eye joint as described in claim 6, characterized in that a fitting portion is provided on the inner periphery of the shaft insertion hole of the cover plate and on the end of the outer periphery of the shaft on the shaft locking portion side, the fitting portion fitting into the shaft when the shaft is attached to the cover plate to prevent the shaft from rotating relative to the cover plate.

8. A dust cap for an eye joint as described in claim 1, characterized in that the retaining portion is an inner peripheral surface of the cylindrical portion and an outer peripheral surface of the shaft portion which detachably retain the shaft portion inserted into the cylindrical portion by friction.

9. A dust cap for an eye joint as described in claim 1, characterized in that the retaining portion is a concave-convex portion provided on the inner peripheral surface of the cylindrical portion and the outer peripheral surface of the shaft portion, which retains the shaft portion in a detachable state inserted into the cylindrical portion.

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