Device for underground construction

Abstract

To easily attach / detach a fall prevention ladder to / from a receiving frame in a device for an underground structure having the receiving frame and the fall prevention ladder.SOLUTION: This fall prevention ladder is provided with a receiving frame 1 forming an opening part 19 connecting a ground G and an underground structure U, a fall prevention ladder 2 opening and closing the opening part 19 and detachably attached to the receiving frame 1, and an attaching / detaching path 3 through which the fall prevention ladder 2 is attached to and detached from the receiving frame 1. The attachment / detachment path 3 includes a pair of first paths 31 for moving the pair of detachable parts 20 one by one in the first direction D1 when the pair of detachable parts 20 are attached to or detached from the pair of support parts 10, and a pair of second paths 32 connected to the pair of first paths 31 one by one and for moving the pair of detachable parts 20 one by one in the second direction D2, the pair of second paths 32 includes an arrangement part 20a capable of arranging the first attaching / detaching part 11a on the underground structure U side of the first restriction part 33a.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an apparatus for underground construction. [Background technology]

[0002] Patent Document 1 describes that the ladder is easy to attach and detach, can be supported and fixed in a stable state when the ladder is erected, and has a locking function that prevents the ladder's engagement part from easily coming loose due to internal pressure, etc. The document also describes that the fall prevention ladder comprises a ladder body consisting of a pair of support rods and a plurality of rungs installed between the pair of support rods, a ladder fixing part that straddles and fixes hand grips formed on the inner periphery of the receiving frame and pivots the base end of the ladder body, and an engagement part that is engaged with a ladder engaging seat formed on the inner periphery of the receiving frame and is provided at the other end of the ladder fixing part. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-100407 A (Abstract) Summary of the Invention [Problem to be solved by the invention]

[0004] In an underground structure device equipped with a receiving frame and a fall prevention ladder as disclosed in Patent Document 1, it is required that the fall prevention ladder be easily attached and detached to and from the receiving frame. [Means for solving the problem]

[0005] One aspect of the present invention is an underground structure device comprising: a first unit that forms an opening connecting the ground and the underground structure; a second unit that opens and closes the opening and is attached to and detached from the first unit; and an attachment / detachment path along which the second unit is attached to and detached from the first unit. The first unit includes a pair of support parts that support the second unit. The second unit includes a pair of detachable parts that are attached to and detached from the pair of support parts, respectively. The attachment / detachment path includes a pair of paths that move each of the pair of detachable parts one by one when the pair of detachable parts are attached to and detached from the pair of support parts. The pair of support parts includes a first restriction part that restricts at least one of the pair of detachable parts from moving above ground when the pair of detachable parts are attached to the pair of support parts. The pair of paths includes a pair of first paths that move each of the pair of detachable parts one by one in a first direction along the direction passing through the opening when the pair of detachable parts are attached to or detached from the pair of support parts, and a pair of second paths that are connected to each of the pair of first paths one by one and move each of the pair of detachable parts one by one in a second direction intersecting the first direction. The pair of second paths includes a positioning part that can position at least one of the detachable parts on the underground structure side of the first regulating part.

[0006] This underground structure device includes a pair of paths along which each of the pair of detachable parts moves one by one when the second unit is attached to or detached from the first unit. The pair of paths includes a pair of first paths along which each of the pair of detachable parts moves one by one in a first direction along the direction passing through the opening, and a pair of second paths connected to each of the pair of first paths, each of which moves each of the pair of detachable parts one by one in a second direction intersecting the first direction. Therefore, by moving the pair of detachable parts along the pair of second paths from a state in which the pair of detachable parts are attached to the pair of support parts, the pair of detachable parts can be easily positioned on the pair of first paths. Therefore, the second unit can be easily removed from the first unit while moving it above ground along the pair of first paths. The pair of second paths also includes a positioning portion that allows at least one of the detachable parts to be positioned on the underground structure side of the first restriction part. Therefore, when attaching the pair of detachable parts to the pair of support parts, by moving the pair of detachable parts from a state in which the pair of detachable parts are arranged on the pair of first paths along the pair of second paths, at least one of the detachable parts can be easily positioned on the underground structure side of the first restricting part. Therefore, even if pressure or the like occurs that causes the second unit to float above ground, it is easy to maintain the attached state of the second unit while preventing it from detaching from the first unit. In this way, by moving the pair of detachable parts along the pair of second paths, the second unit can be easily attached and detached to the first unit.

[0007] Preferably, the pair of support parts includes a second restricting part that restricts movement of at least one of the pair of detachable parts to one side in the second direction when the pair of detachable parts is attached to the pair of support parts. Even if an external force that moves the second unit to one side in the second direction occurs, the attachment state of the second unit can be easily maintained while preventing displacement of the second unit.

[0008] Preferably, the first support portion of the pair of support portions includes a first surface and a first protruding portion protruding from the first surface toward the ground, and the first protruding portion includes a third restricting portion that restricts the first detachable portion of the pair of detachable portions from moving toward the other side in the second direction when the first detachable portion is attached to the first support portion. Even if an external force or the like occurs that moves the second unit toward the other side in the second direction, it is easy to maintain the attached state of the second unit while preventing the second unit from shifting position.

[0009] Preferably, the first surface includes a first installation surface on which the first detachable part is installed, and the first protrusion includes an inclined portion that is inclined so that the first detachable part is guided toward the first installation surface when the first detachable part is installed on the first installation surface. By moving the first detachable part along the inclined portion, the first detachable part can be easily installed on the first installation surface.

[0010] The second unit preferably includes a mesh-like linear portion that forms a gap penetrating in the first direction when the second unit has the opening closed, and a gripping portion arranged to overlap the linear portion in the first direction. The gripping portion, which is grasped by workers or the like when accessing the underground structure, is arranged to overlap the mesh-like linear portion in the first direction, preventing the gripping portion from covering the gap formed by the mesh-like linear portion from the first direction. Therefore, even if pressure or the like that causes the second unit to float above ground occurs, the gripping portion is likely to prevent the release of pressure or the like through the gap from being obstructed. Therefore, the second unit is likely to be prevented from floating above ground.

[0011] It is preferable to further include an elastic member that applies elastic force between the second support part of the pair of support parts and the second detachable part of the pair of detachable parts so that the second unit maintains its position when the opening is open. Because the position of the second unit can be maintained when the opening is open, workers can easily and efficiently perform inspections and other tasks. [Brief explanation of the drawings]

[0012] [Figure 1] Figure 1 is a schematic diagram of a manhole system. [Figure 2] FIG. 2 is a plan view of an underground structure device according to one embodiment of the present invention. [Figure 3] FIG. 3 is a cross-sectional view of the underground structure device shown in FIG. 2 (cross-section III-III in FIG. 2). [Figure 4] 4 is a perspective view showing the second unit (fall prevention ladder) provided in the underground structure device shown in FIG. 2 in an upright state. [Figure 5] 5 is a perspective view showing an elastic member provided in the underground structure device shown in FIG. 2. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0013] An underground structure device according to one embodiment of the present invention will be described in detail below. However, the present invention is not limited to this embodiment. Furthermore, the components in the following embodiment include those that are easily replaceable by those skilled in the art, or those that are substantially identical. Furthermore, the configurations described below can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the configuration can be made without departing from the spirit of the present invention.

[0014] Fig. 1 is a schematic diagram of a manhole system. As shown in Fig. 1, the manhole system S includes an underground structure U connected to an underground facility to be inspected (not shown) so that workers can access it, and an underground structure device 100 connecting the ground G and the underground structure U.

[0015] The underground structure equipment 100 comprises a first unit (receiving frame) 1 that forms an opening 19, and a second unit (fall prevention ladder) 2 that opens and closes this opening 19. The fall prevention ladder 2 is configured to be attachable and detachable to the receiving frame 1. The underground structure equipment 100 also comprises an attachment and detachment path 3 along which the fall prevention ladder 2 is attached and detached to and from the receiving frame 1. The opening 19 can be kept closed by attaching an underground structure cover (manhole cover) 4 to the receiving frame 1.

[0016] Fig. 2 is a plan view of an underground structure equipment 100 according to one embodiment of the present invention. Fig. 3 is a cross-sectional view (cross section III-III in Fig. 2) of the underground structure equipment 100 shown in Fig. 2. The underground structure equipment 100 of this embodiment will be described in detail below.

[0017] As described above, the underground structure device 100 comprises a receiving frame 1 that forms an opening 19 connecting the ground G and the underground structure U, a fall prevention ladder 2 that opens and closes the opening 19 and is attached and detached to the receiving frame 1, and an attachment and detachment path 3 along which the fall prevention ladder 2 is attached and detached to and from the receiving frame 1 (see Figures 2 and 3).

[0018] The receiving frame 1 includes a pair of support parts 10 (first support part 10a, second support part 10b) that support the fall prevention ladder 2. The fall prevention ladder 2 includes a pair of detachable parts 20 (first detachable part 20a, second detachable part 20b) that are attached to and detached from each of the pair of support parts 10. The attachment and detachment path 3 includes a pair of paths 30 (one path 30a, the other path 30b) that move each of the pair of detachable parts 20 one by one when the pair of detachable parts 20 are attached to and detached from the pair of support parts 10.

[0019] The first support part 10a includes a first restricting part 11a that restricts the first detachable part 20a from moving toward the ground G when the first detachable part 20a is attached to the first support part 10a. The second support part 10b includes a first restricting part 11b that restricts the second detachable part 20b from moving toward the ground G when the second detachable part 20b is attached to the second support part 10b.

[0020] Furthermore, the first support part 10a includes a second restricting part 12a that restricts the first detachable part 20a from moving toward one side D21 in the second direction D2 when the first detachable part 20a is attached to the first support part 10a. The second support part 10b includes a second restricting part 12b that restricts the second detachable part 20b from moving toward one side D21 in the second direction D2 when the second detachable part 20b is attached to the second support part 10b.

[0021] The first support part 10a also includes a first surface 13a and a first protrusion 17 that protrudes from the first surface 13a toward the ground G. The first protrusion 17 includes a third restriction part 16 that restricts the first detachable part 20a from moving toward the other side D22 in the second direction D2 when the first detachable part 20a is attached to the first support part 10a.

[0022] The first surface 13a also includes a first installation surface 14a on which the first detachable part 20a is installed. The first protrusion 17 includes an inclined part 15a that is inclined so that the first detachable part 20a is guided toward the first installation surface 14a when the first detachable part 20a is installed on the first installation surface 14a.

[0023] One path 30a includes a first path 31a that moves the first detachable part 20a in a first direction D1 that is along the direction passing through the opening 19 when the first detachable part 20a is attached to or detached from the first support part 10a, and a second path 32a that is continuous with the first path 31a and moves the first detachable part 20a in a second direction D2 that intersects with the first direction D1. The other path 30b includes a first path 31b that moves the second detachable part 20b in the first direction D1 when the second detachable part 20b is attached to or detached from the second support part 10b, and a second path 32b that is continuous with the first path 31b and moves the second detachable part 20b in the second direction D2. In this way, when the first detachable unit 20a and the second detachable unit 20b are moved one by one along the one path 30a and the other path 30b, the first detachable unit 20a and the second detachable unit 20b move in conjunction with each other in the first direction D1 and the second direction D2. The second path 32a includes a positioning unit 33a that can position the first detachable unit 20a on the underground structure U side of the first restriction unit 11a. The second path 32b includes a positioning unit 33b that can position the second detachable unit 20b on the underground structure U side of the first restriction unit 11b.

[0024] Next, we will explain the structure of the receiving frame 1. As shown in Fig. 2, the receiving frame 1 has a cylindrical shape when viewed from the first direction D1.

[0025] Furthermore, the receiving frame 1 includes a pair of support portions 10 (first support portion 10a, second support portion 10b) and another pair of support portions 10 (first support portion 10c, second support portion 10d). Thus, in this embodiment, the fall prevention ladder 2 is supported at four locations: the first support portion 10a, the second support portion 10b, the first support portion 10c, and the second support portion 10d.

[0026] 3, first support portion 10a supports first detachable portion 20a, and first support portion 10a is formed with arrangement portion 33a, which is a section in which first detachable portion 20a is arranged. Arrangement portion 33a is formed by cutting out the inner wall surface of receiving frame 1, and first detachable portion 20a fits into and is supported therein. The same applies to first support portion 10c.

[0027] The first restricting portion 11a includes a first restricting surface 11a1 that restricts the first detachable portion 20a from moving toward one side D11 in the first direction D1 when the first detachable portion 20a comes into contact with the first restricting surface 11a1. The first restricting surface 11a1 is disposed on one side D11 in the first direction D1 with respect to the arrangement portion 33a. The second restricting portion 12a includes a second restricting surface 12a1 that restricts the first detachable portion 20a from moving toward one side D21 in the second direction D2 when the first detachable portion 20a comes into contact with the second restricting surface 12a1. The second restricting surface 12a1 is disposed on one side D21 in the second direction D2 with respect to the arrangement portion 33a. The same applies to the first support portion 10c.

[0028] The third restricting portion 16 also includes a third restricting surface 161 that restricts the first detachable portion 20a from moving toward the other side D22 in the second direction D2 when the first detachable portion 20a comes into contact with the third restricting surface 161. The third restricting surface 161 is disposed on the other side D22 in the second direction D2 with respect to the arrangement portion 33a. The first restricting portion 11a (first restricting surface 11a1), the second restricting portion 12a (second restricting surface 12a1), and the third restricting portion 16 (third restricting surface 161) can restrict the first detachable portion 20a from moving toward the ground G and toward both sides in the second direction D2.

[0029] The first protrusion 17 is formed so that its height gradually decreases from the other side D22 to the one side D21 in the second direction D2. In this way, the cross section of the first protrusion 17 is formed to be approximately trapezoidal. Therefore, when the first detachable part 20a is placed on the first installation surface 14a, the first detachable part 20a can be easily placed on the first installation surface 14a by moving the first detachable part 20a along the downwardly inclined slope 15a. The same applies to the first support part 10c.

[0030] As shown in FIG. 2, the second support portion 10b supports the second detachable portion 20b and includes a support base portion 61 formed to bridge the receiving frame 1 across the opening 19, and a substantially L-shaped hook portion 62 formed on the support base portion 61, to which the second detachable portion 20b is engaged (see FIG. 3). The hook portion 62 includes a first extension portion 621 extending from the support base portion 61 to one side D11 in the first direction D1, and a second extension portion 622 extending from the first extension portion 621 to the other side D22 in the second direction D2. In this embodiment, the first extension portion 621 functions as the second restricting portion 12b, and the second extension portion 622 functions as the first restricting portion 11b. Furthermore, on the other side D12 of the hook portion 62 in the first direction D1, an insertion portion 63 is formed into which the second detachable portion 20b can be inserted when the fall prevention ladder 2 is in an upright state. In this embodiment, the insertion portion 63 penetrates in the first direction D1. The same applies to the second support portion 10d.

[0031] As shown in FIG. 3, the first restricting portion 11b includes a first restricting surface 11b1 that restricts the second detachable portion 20b from moving toward the ground G when the second detachable portion 20b comes into contact with the first restricting surface 11b1. The first restricting surface 11b1 is disposed on one side D11 in the first direction D1 with respect to the arrangement portion 33b. The second restricting portion 12b includes a second restricting surface 12b1 that restricts the second detachable portion 20b from moving toward one side D21 in the second direction D2 when the second detachable portion 20b comes into contact with the first restricting surface 11b1. The second restricting surface 12b1 is disposed on one side D21 in the second direction D2 with respect to the arrangement portion 33b. The same applies to the second support portion 10d.

[0032] These first regulating portion 11b (first regulating surface 11b1) and second regulating portion 12b (second regulating surface 12b1) can regulate the second detachable portion 20b from moving toward the ground G and toward one side D21 of the second direction D2.

[0033] Next, we will explain the specific structure of the fall prevention ladder 2. As shown in Fig. 2, the fall prevention ladder 2 includes a mesh-like linear portion 22 that forms gaps 21 that penetrate in the first direction D1 when the fall prevention ladder 2 has the opening 19 closed, and a grip portion 23 that is arranged to overlap the linear portion 22 in the first direction D1 (see Fig. 4).

[0034] 2, the linear portion 22 includes first linear portions 22a arranged at a predetermined interval and extending in the second direction D2, and second linear portions 22b arranged at a predetermined interval from the first linear portions 22a so as to overlap in the first direction D1 with respect to the first linear portions 22a and extending perpendicular to the first linear portions 22a. Since the first linear portions 22a and the second linear portions 22b are arranged perpendicular to each other in this manner, a gap 21 penetrating in the first direction D1 can be formed. In this embodiment, the first linear portions 22a and the second linear portions 22b are each formed by bending a single linear material, and the bent portions 25 are joined to the main frame 24.

[0035] The gripping portion 23 is formed by bending a linear material and has a generally rectangular shape with rounded vertices. The gripping portion 23 is disposed so as to overlap the first linear portion 22a at a distance in the first direction D1 so that an operator or the like can easily grasp the gripping portion 23 (see FIG. 4).

[0036] The gripping portion 23 and the first linear portion 22a overlap in the first direction D1, preventing the gaps 21 formed by the mesh-like linear portion 22 from being covered by the gripping portion 23. As a result, even if pressure or the like occurs within the underground structure U, the pressure is released through the gaps 21, preventing the fall prevention ladder 2 from floating up to the ground G side.

[0037] Next, we will explain the state in which the opening 19 is opened by the fall prevention ladder 2 (hereinafter sometimes referred to as the "open state"). Here, Fig. 4 is a perspective view showing the upright state of the fall prevention ladder 2 provided in the underground structure equipment 100 shown in Fig. 2. Fig. 5 is a perspective view showing the elastic member 5 provided in the underground structure equipment 100 shown in Fig. 2. As shown in Fig. 4, the second support part 10b includes an insertion part 63 into which the second detachable part 20b can be inserted, and a groove part 64 formed in the support base part 61 so that the side part 26 of the main frame 24 can be attached. In addition, the underground structure equipment 100 includes the elastic member 5 attached to the second detachable part 20b. When the second detachable portion 20b of the fall prevention ladder 2 is inserted into the insertion portion 63 and the side portion 26 of the main frame 24 is attached to the groove portion 64, the elastic member 5 applies an elastic force between the second support portion 10b and the second detachable portion 20b, thereby maintaining the fall prevention ladder 2 in an upright position.

[0038] As shown in Figures 4 and 5, the elastic member 5 includes a first cover portion 51 that partially covers the second detachable portion 20b, a second cover portion 52 that partially covers the side portion 26 of the main frame 24, and a connecting portion 53 that connects the first cover portion 51 and the second cover portion 52, the connecting portion 53 being elastically deformable.

[0039] When the fall prevention ladder 2 is in an upright position, the side 26 of the main frame 24 is positioned in the groove portion 64 via the second cover portion 52, so that the side 26 of the main frame 24 is sandwiched from both sides in the second direction D2, thereby preventing the fall prevention ladder 2 from falling toward the opening 19.

[0040] 4, the insertion portion 63 includes a contact surface 65 that can come into contact with the connection portion 53 of the elastic member 5. As a result, when the opening 19 is in the open state, the elastic force generated by pressing the connection portion 53 of the elastic member 5 against the contact surface 65 of the insertion portion 63 functions as a pull-out resistance for the fall prevention ladder 2.

[0041] Next, the procedure for operating the fall prevention ladder 2 from the attached state to the detached state of the fall prevention ladder 2 will be described.

[0042] When the fall prevention ladder 2 closes the opening 19, the pair of detachable parts 20 are supported by the pair of support parts 10, as described above (see Figures 2 and 3). To remove the fall prevention ladder 2 from the receiving frame 1 from this state, first, each of the pair of detachable parts 20 is moved one by one along each of the pair of second paths 32. This causes each of the pair of detachable parts 20 to reach each of the pair of first paths 31.

[0043] Next, in this state, the fall prevention ladder 2 can be removed from the receiving frame 1 by moving each of the pair of attachment / detachment parts 20 one by one along each of the pair of first paths 31. In this way, by moving the pair of attachment / detachment parts 20 along the pair of paths 30 while interlocking them, the fall prevention ladder 2 can be easily removed from the receiving frame 1.

[0044] On the other hand, the operating procedure for the fall prevention ladder 2 from the detached state to the attached state can be performed in the reverse order to that described above, by moving the pair of attachment / detachment parts 20 along the pair of paths 30 while interlocking them, thereby easily attaching the fall prevention ladder 2 to the receiving frame 1.

[0045] As described above, this underground structure device 100 includes a pair of paths 30 along which each of the pair of detachable parts 20 is moved one by one when the fall prevention ladder 2 is attached to or detached from the receiving frame 1. The pair of paths 30 includes a pair of first paths 31 along which each of the pair of detachable parts 20 is moved one by one in a first direction D1 along the direction passing through the opening 19, and a pair of second paths 32 connected to each of the pair of first paths 31, and which move each of the pair of detachable parts 20 one by one in a second direction D2 intersecting the first direction D1. Therefore, by moving the pair of detachable parts 20 along the pair of second paths 32 from a state in which the pair of detachable parts 20 are attached to the pair of support parts 10, the pair of detachable parts 20 can be easily positioned on the pair of first paths 31. Therefore, the fall prevention ladder 2 can be easily removed from the receiving frame 1 while being moved toward the ground G along the pair of first paths 31. In addition, the second path 32a includes a positioning portion 33a that allows the first detachable part 20a to be positioned on the underground structure U side of the first regulating part 11a, and the second path 32b includes a positioning portion 33b that allows the second detachable part 20b to be positioned on the underground structure U side of the first regulating part 11b. Therefore, when attaching the pair of detachable parts 20 to the pair of support parts 10, by moving the pair of detachable parts 20 along the pair of second paths 32 from a state in which the pair of detachable parts 20 are positioned on the pair of first paths 31, the first detachable part 20a can be easily positioned on the underground structure U side of the first regulating part 11a, and the second detachable part 20b can be easily positioned on the underground structure U side of the first regulating part 11b. Therefore, even if pressure or the like occurs that causes the fall prevention ladder 2 to float toward the ground G, it is easy to maintain the attached state of the fall prevention ladder 2 while preventing it from coming off the receiving frame 1. In this way, by moving the pair of attachment / detachment parts 20 along the pair of second paths 32, the fall prevention ladder 2 can be easily attached and detached to the receiving frame 1.

[0046] Furthermore, the first support part 10a includes a second restriction part 12a that restricts the first detachable part 20a from moving to one side D21 in the second direction D2 when the first detachable part 20a is attached to the first support part 10a, and the second support part 10b includes a second restriction part 12b that restricts the second detachable part 20b from moving to one side D21 in the second direction D2 when the second detachable part 20b is attached to the second support part 10b. Therefore, even if an external force or the like occurs that moves the fall prevention ladder 2 to one side D21 in the second direction D2, it is easy to maintain the attached state of the fall prevention ladder 2 while preventing the fall prevention ladder 2 from shifting position.

[0047] Furthermore, the first support part 10a includes a first surface 13a and a first protrusion 17 that protrudes from the first surface 13a toward the ground G, and the first protrusion 17 includes a third regulating part 16 that regulates the first detachable part 20a from moving toward the other side D22 of the second direction D2 when the first detachable part 20a is attached to the first support part 10a. Therefore, even if an external force or the like occurs that moves the fall prevention ladder 2 toward the other side D22 of the second direction D2, it is easy to maintain the attached state of the fall prevention ladder 2 while preventing the fall prevention ladder 2 from shifting position.

[0048] Furthermore, first surface 13a includes first installation surface 14a on which first detachable part 20a is installed, and first protrusion 17 includes inclined portion 15a that is inclined so that first detachable part 20a is guided toward first installation surface 14a when first detachable part 20a is installed on first installation surface 14a. Therefore, first detachable part 20a can be easily installed on first installation surface 14a by moving first detachable part 20a along inclined portion 15a.

[0049] Furthermore, the fall prevention ladder 2 includes a mesh-like linear portion 22 that forms a gap 21 penetrating in the first direction D1 when the fall prevention ladder 2 closes the opening 19, and a gripping portion 23 that is arranged to overlap the linear portion 22 in the first direction D1. In this way, the gripping portion 23, which is gripped by a worker or the like when accessing the underground structure U, is arranged to overlap the mesh-like linear portion 22 in the first direction D1, so that the gap 21 formed by the mesh-like linear portion 22 can be prevented from being covered by the gripping portion 23 from the first direction D1. Therefore, even if pressure or the like that causes the fall prevention ladder 2 to float toward the ground G is generated, it is easy to prevent the gripping portion 23 from obstructing the release of pressure or the like through the gap 21. Therefore, it is easy to prevent the fall prevention ladder 2 from floating toward the ground G.

[0050] In addition, this underground structure device 100 further includes an elastic member 5 that applies an elastic force between the second support part 10b and the second detachable part 20b so as to maintain the posture of the fall prevention ladder 2 when the opening 19 of the fall prevention ladder 2 is open. In this way, the posture of the fall prevention ladder 2 can be maintained with the opening 19 open, making it easier for workers to efficiently carry out inspections and other tasks. [Explanation of symbols]

[0051] S manhole system, G ground, U underground structure, 100 underground structure device, 1 first unit (receiving frame), 2 second unit (fall prevention ladder), 3 attachment / detachment path, 4 underground structure cover (manhole cover), 5 elastic member, 10 pair of support parts, 10a first support part, 10b second support part, 11a, 11b first restricting part, 12a, 12b second restricting part, 13a first surface, 14a first installation surface, 15a inclined part, 16 third restricting part, 17 first protruding part, 19 opening, 20 pair of attachment / detachment parts, 20a first attachment / detachment part, 20b second attachment / detachment part, 21 gap, 22 linear part, 23 gripping part, 30 pair of paths, 31 pair of first paths, 32 A pair of second paths, 33a and 33b, arranged in

Claims

1. a first unit that forms an opening that connects the ground and the underground structure; a second unit that opens and closes the opening and is detachably attached to the first unit; An underground structure device comprising: an attachment / detachment path through which the second unit passes when being attached to and detached from the first unit; the first unit includes a pair of support portions that support the second unit; the second unit includes a pair of detachable portions that are attached to and detached from the pair of support portions, respectively; the attachment / detachment path includes a pair of paths along which the pair of detachable parts are moved one by one when the pair of detachable parts are attached to or detached from the pair of support parts, the pair of support parts includes a first restriction part that restricts movement of at least one of the pair of detachable parts toward the ground when the pair of detachable parts is attached to the pair of support parts, the pair of paths includes a pair of first paths that move each of the pair of detachable parts one by one in a first direction along a direction passing through the opening when the pair of detachable parts are attached to or detached from the pair of support parts; a pair of second paths each connected to the pair of first paths, the pair of second paths moving each of the pair of attachment / detachment units one by one in a second direction intersecting the first direction; An underground structure device, wherein the pair of second paths includes a positioning portion that enables at least one of the detachable portions to be positioned on the underground structure side of the first regulating portion.

2. An underground structure device as described in claim 1, wherein the pair of support parts include a second regulating part that regulates movement of at least one of the detachable parts in one direction when the pair of detachable parts are attached to the pair of support parts.

3. The first support portion of the pair of support portions has a first surface and a first protrusion protruding from the first surface toward the ground, The underground structure device described in claim 1, wherein the first protrusion includes a third regulating portion that regulates the movement of the first detachable portion of the pair of detachable portions toward the other side of the second direction when the first detachable portion is attached to the first support portion.

4. the first surface includes a first installation surface on which the first attachment / detachment unit is installed, The underground structure device of claim 3, wherein the first protrusion includes an inclined portion that is inclined so that the first detachable portion is guided toward the first installation surface when the first detachable portion is installed on the first installation surface.

5. the second unit includes a mesh-like linear portion that forms gaps that penetrate in the first direction when the second unit closes the opening; The underground structure device according to claim 1 , further comprising a gripping portion arranged to overlap the linear portion in the first direction.

6. An underground structure device as described in any one of claims 1 to 5, further comprising an elastic member that applies an elastic force between a second support portion of the pair of support portions and a second detachable portion of the pair of detachable portions so as to maintain the posture of the second unit when the second unit opens the opening.

Images