JP2015078511A - Reversal device of manhole cover - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reversal device of a manhole cover, for gently reversing by dead weight, and also reversible without requiring strong force when reversing.SOLUTION: In a reversal device 1 of a manhole cover for reversing a manhole cover 10 held by holding means 20, the cover 10 comprises a disk-like cover part 11 and a rib part 12 formed under the cover part 11, and the holding means 20 comprises a pair of support shafts 12 for holding the cover part 11 from the side surface side and forming a rotational center 26A when reversing the cover 10, in a position opposed to the diametrical direction of the cover 10, and a support shaft 26 is arranged so that the rotational center 26A is parallel to a gravity center surface 13A of passing through the center of gravity 13 of the cover 10 and is also positioned in a thickness directional area of the cover 10.

Description

  The present invention relates to an apparatus for inverting a manhole cover.

  The manhole cover is normally closed, but when working inside the manhole, it is necessary to open and close the cover. Since the manhole cover is a heavy object formed of forged steel or the like, the cover is opened and closed using a dedicated device or a crane. Moreover, since a lid | cover deteriorates by use for many years, it is necessary to check the back surface. In that case, lift the lid and turn it over to check if there is any cracks on the back.

  For example, Patent Document 1 and Patent Document 2 have been proposed as devices for lifting and reversing a manhole cover. The lid opening / closing reversing device disclosed in Patent Document 1 removes the inner lid while lifting the lid, and reverses the lid using the hole of the manhole. Moreover, the opening / closing apparatus described in Patent Document 2 is reversed by lifting a lid by a lift member.

JP 11-050485 A JP 2008-095411 A

  In both Patent Document 1 and Patent Document 2, as shown in FIG. 7, a shaft 110 is fixed to a manhole cover 100 in a covered state by a fixing means 120, and the shaft 110 is lifted together with the cover 100. It is shown that the lid 100 is reversed with 110 as the rotation center 110A. However, since the shaft 110 is fixed above the lid 100 in the covered state, the rotation center 110 </ b> A of the lid 100 is positioned above the thickness direction region of the lid 100. For this reason, when the lid 100 is inverted, a considerable flat force is required because the horizontal plane (centroid surface 130A) passing through the center of gravity 130 of the lid 100, which is a heavy object, is separated from the rotation center 110A. In addition, after performing work such as inspection and cleaning in the state where the lid 100 is inverted, when the lid 100 is returned to the original state, there is a possibility that it may be vigorously inverted due to the weight (self-weight) of the lid 100.

  In view of the above circumstances, the technical problem to be solved by the present invention is that the manhole cover is reversed by its own weight and can be reversed without requiring a strong force when further reversing. To provide an apparatus.

  In order to solve the above problems, a manhole cover reversing device according to the present invention is a manhole cover reversing device for reversing a manhole cover held by a holding means, and the cover is a disc-shaped cover. And a rib portion formed below the lid portion, and the holding means holds the lid portion from the side surface and has a rotation center at the time of reversing the lid at a position opposed to the diameter direction of the lid. It has a pair of supporting shafts to be formed, and the supporting shafts are arranged so that the center of rotation is parallel to the center of gravity passing through the center of gravity of the lid and located in the thickness direction region of the lid.

  In this way, the holding means holds the lid portion of the lid from the side surface side and has a pair of support shafts that oppose each other in the diameter direction of the lid. Therefore, a straight line connecting these support shafts is rotated when the cover is reversed. Become the center. Here, the center of gravity surface of the lid refers to a horizontal plane passing through the center of gravity of the lid in the mounted state. Moreover, the attitude | position of a lid | cover is stabilized because the gravity center surface of a lid | cover is located below a rotation center. For this reason, when the center of gravity surface of the lid is positioned above the center of rotation, the lid is inverted by its own weight. The center of rotation is parallel to the center of gravity plane passing through the center of gravity of the lid, and is disposed in the thickness direction region of the lid, so that the center of gravity surface and the center of rotation are disposed close to each other. For this reason, when the center of gravity surface of the lid is positioned above the center of rotation, the lid can be gently reversed by its own weight by lifting the lid. In addition, when the center of gravity and the center of rotation coincide with each other and when the center of gravity is located below the center of rotation, the lid can be inverted manually without requiring a strong force.

  The holding means includes a pair of arc members and a link member that connects the pair of arc members, and each arc member includes an arc-shaped support plate that supports the lid from the thickness direction of the lid, and a support A central position of the plate and a plurality of holding portions that are arranged at equal intervals from the central position and hold the side surface of the lid portion, and the support portion that is disposed at the central position is provided with a support shaft. The holding portion arranged at a position spaced apart from the central position is provided with a connecting hole to which the link member is connected, and the link member has a pair of arcs so that the support shaft faces the diameter direction of the lid. You may make it connect a member. Thus, the lid can be held only by connecting the pair of arc members with the link member. Thereby, since it is not necessary to connect an arc member and a cover part, a holding means can be easily attached to a cover. Further, by connecting the link member to the arc member, the support shaft can be arranged so as to face the lid in the diameter direction. As a result, the center of rotation of the lid can be formed in the diameter direction, and the lid can be stably reversed.

  The link member is preferably a pair of plate-like members that are rotatably connected with an intersection as a rotation axis. Thereby, the intersection of a plate-shaped member can be arrange | positioned on a rotation center by connecting each edge part of a plate-shaped member to the connection hole of a holding | maintenance part. Therefore, positioning of the holding means can be performed easily and reliably.

  Moreover, it is more preferable that the support portion is provided on the back surface side of the center of gravity surface of the lid in the thickness direction of the lid portion. Thereby, since the center of gravity surface is located above the center of rotation, the lid can be inverted by its own weight by lifting the lid held by the holding means.

  Furthermore, you may provide the raising / lowering machine which has a connection part connectable with a spindle and can raise / lower a lid | cover. Accordingly, the lid can be lifted by the elevator in a state where the connecting portion is connected to the support shaft. Therefore, it is possible to easily lift and reverse the lid.

  At this time, it is preferable that a plurality of the elevators are arranged at positions higher than the radial dimension of the lid and facing each other in the diameter direction of the lid. Thereby, since the elevator is provided at a position higher than the radial dimension of the lid, the elevator can be reliably reversed by lifting the lid. At this time, if the lifting mechanism is provided at a position slightly higher than the radial dimension of the lid, the upper limit of lifting can be adjusted by the opposing elevators, so that the inclination of the lid is suppressed when the lid is reversed. , It can be almost horizontal.

  As described above, according to the present invention, it is possible to provide a manhole cover reversing device that can be gently reversed by its own weight and can be reversed without requiring a strong force when further reversing. It becomes.

It is a perspective view which shows the inversion apparatus of the manhole cover concerning one Embodiment of this invention. (A) is a top view of the circular arc member in the inversion apparatus shown in FIG. 1, (b) is a (a) side view. (C) is XX sectional drawing of (b). (A) is a top view which shows the holding state of the lid | cover by a holding means, (b) is the YY sectional view taken on the line of (a). It is a conceptual diagram which shows the state at the time of a lifting start in the inversion operation | movement of the lid | cover by the inversion apparatus shown in FIG. In the reversing operation of the lid, the state during lifting is shown. The state when the lid is inverted is shown. (A) is a top view which shows the holding state of the lid | cover by the holding means in the conventional inversion apparatus, (b) is a side view.

  Hereinafter, an embodiment of a manhole cover reversing device according to the present invention will be described with reference to the drawings.

  The reversing device 1 of the manhole cover 10 according to the present invention is a device that lifts and reverses the manhole cover 10. As shown in FIG. 1, the reversing device 1 of the manhole cover 10 includes a holding unit 20 that holds the lid 10, an elevator 30 that can be connected to the holding unit 20 to raise and lower the lid 10, and a support that supports the elevator 30. And a body 40.

  The lid | cover 10 is a lid | cover material applied to the opening part of a manhole, for example, consists of metal materials, such as forged steel. Hereinafter, the surface of the lid 10 that is exposed to the ground surface in the covered state is referred to as a front surface, and the opposite surface is referred to as a back surface. As shown in FIG. 3, the lid 10 includes a thick disc-shaped lid portion 11 and rib portions 12 formed in a lattice shape below the lid portion 11 (on the back surface side). In the present embodiment, the lid 10 has a diameter of about 870 mm and a thickness of about 80 mm. Moreover, since the cover part 11 has protruded to the outer diameter side rather than the rib part 12, when the rib part 12 is mounted so that it may touch the ground, the edge part of the cover part 11 will be in the state away from the ground. Hereinafter, a horizontal plane passing through the center of gravity 13 of the placed lid 10 is referred to as a center of gravity surface 13A (see FIG. 3B).

  The holding means 20 is a member that is attached to the lid 10 and holds the lid portion 11 from the side surface side, and includes a pair of arc members 21 and a link member 22. By connecting a pair of arc members 21 mounted on the lid 10 by link members 22, the lid 10 is held so as to be lifted and inverted.

  As shown in FIG. 2, the arc member 21 has a pair of holding plates 23 arranged in the vertical direction, and a plurality of holding portions 24 arranged on these holding plates 23 at equal intervals. A plurality of support protrusions 25 are attached to the upper holding plate 23 in the drawing.

  The holding plate 23 is an arc-shaped plate material having the same curvature as the lid portion 11 of the lid 10. In the present embodiment, the length of the holding plate 23 is about 1/6 of the entire circumference of the lid 11. Further, as shown in FIGS. 2A and 2B, the holding plate 23 disposed on the surface side of the lid 10 is formed with an attachment hole 23 </ b> A for attaching the support protrusion 25.

  As shown in FIG. 2C, which is a cross-sectional view taken along line XX of FIG. 2B, the holding portion 24 has an opening that opens in a substantially U-shape, and is opposed to the vertical direction shown in the drawing. A holding plate 23 is attached to the flat surface. At this time, the distance between the pair of holding plates 23 facing each other is slightly larger than the thickness dimension of the lid portion 11, and is a size capable of holding the lid portion 11 by the holding plate 23. The holding portion 24 is attached along the outer periphery of the holding plate 23, and is arranged so that the opening faces the inner diameter side of the arc.

  Here, as shown in FIG. 2A, the holding portion 24 is disposed at the center position of the holding plate 23 and in the vicinity of both end portions that are equidistant from the center position on both sides. Hereinafter, the holding portion 24 at the center of the holding plate 23 is referred to as a holding portion 24A, and each holding portion 24 near both ends is referred to as a holding portion 24B. Thereby, the arc member 21 can hold the edge portion (see FIG. 3) of the lid portion 11 of the lid 10 from the front and back directions by the holding plate 23, and the outer surface of the side surface of the lid portion 11 by the holding portion 24. It can be held from the side.

  A support shaft 26 that protrudes toward the outer diameter side of the holding plate 23 is provided in the holding portion 24A. Since the support shaft 26 is provided in the holding portion 24 </ b> A, the support shaft 26 is disposed in the thickness direction region of the lid 10. Further, the support shaft 26 becomes a fulcrum when the arc member 21 is mounted on the lid portion 11, and a straight line connecting the support shafts 26 is a rotation center 26 </ b> A when the cover 10 is reversed (FIG. 3B). ))). In the present embodiment, the support shaft 26 is provided near the lower end of the holding portion 24A. Specifically, the support shaft 26 is disposed so that the distance between the rotation center 26A and the center of gravity surface 13A is about 20 mm. In this way, the support shaft 26 is installed in the thickness direction region of the lid portion 11. Here, in the support shaft 26, the distance between the rotation center 26A and the center of gravity surface 13A with respect to the thickness dimension of the lid 10 (distance between the rotation center 26A and the center of gravity surface 13A / thickness dimension of the lid 10) is 0 to 1/2. It is preferable that it is 1/8 to 1/4. The distance between the rotation center 26A and the center of gravity surface 13A with respect to the thickness dimension of the lid 10 is 0 when the rotation center 26A coincides with the center of gravity surface 13A.

  A ring member 27 is attached to the tip of the support shaft 26. The ring member 27 can rotate 180 degrees around an attachment shaft (not shown) attached perpendicular to the axial direction of the support shaft 26 and is 360 degrees with respect to the support shaft 26 around the support shaft 26. It can be rotated.

  Further, the holding portion 24B is disposed near both end portions of the holding plate 23 so that the distance from the holding portion 24A is equal. As shown in FIG. 2A, screw holes 24C as connecting holes for fixing the link member 22 are formed on the surface side of the lid 10 of the holding portion 24B. The screw hole 24C is formed through the holding portion 24B and the holding plate 23.

  The support protrusion 25 is a cylindrical member attached to the holding plate 23. Specifically, it is attached to attachment holes 23A formed in the holding plate 23 on the surface side of the lid 10 at two locations between the holding portion 24A and each holding portion 24B. Further, the support protrusion 25 has a height dimension higher than that of the holding portions 24A and 24B, and when the inverted lid 10 is placed on the ground, the support means 25 is held by the tip of the support protrusion 25 coming into contact with the ground. 20 is supported.

  As shown in FIG. 3A, the link member 22 is composed of a pair of plate-like members having substantially the same dimensions as the diameter of the lid 10. Each member is connected so as to be rotatable about the intersection 22A as a rotation axis. In addition, screw holes (not shown) are formed at the end portions of the respective members. The link member 22 has a screw hole formed at an end thereof, and is screwed together with a screw hole 24C formed in the holding portion 24B by a bolt 28 (see FIG. 1). As a result, the opposing arc members 21 are connected to face each other in the diameter direction of the lid 10.

  FIG. 3 shows a state in which the holding means 20 is attached to the lid 10. 3A is a plan view, and FIG. 3B is a schematic diagram of a cross-sectional view taken along line YY of FIG. In FIG. 3B, the holding portion 24B and the link member 22 are omitted. As shown to Fig.3 (a), a pair of circular arc member 21 is each mounted | worn to the edge part of the cover part 11 of the cover 10 facing a diameter direction. Each arc member 21 is connected by a link member 22. As a result, the holding means 20 can restrain the lid 10 by the arc member 21 and prevent the lid 10 from dropping due to dropping from the holding means 20 when the lid 10 is lifted or reversed. The intersection 22A of the link member 22 is included in the axis passing through the center of gravity 13A of the lid 10.

  Further, as shown in FIG. 3B, the pair of support shafts 26 provided in the holding portion 24 </ b> A of the holding means 20 facing each other are shifted in the thickness direction of the lid 10 with respect to the center of gravity surface 13 </ b> A of the lid 10. Placed in. Accordingly, a rotation center 26A that is a straight line connecting the respective support shafts 26 and serves as an axis when the lid 10 is reversed is parallel to the center of gravity surface 13A. In the present embodiment, the opposite support shaft 26 is disposed on the back surface side (downward) from the center of gravity surface 13 </ b> A of the lid 10. For this reason, the rotation center 26 </ b> A, which is a straight line connecting the respective support shafts 26, is formed on the back side of the center of gravity surface 13 </ b> A of the lid 10.

  Next, a mechanism for raising and lowering the lid 10 will be described. In the present embodiment, as shown in FIG. 1, the mechanism for raising and lowering the lid 10 includes a pair of elevators 30 that are arranged to face each other and a support body 40 that supports each elevator 30.

  The elevator 30 uses a manual winch in this embodiment. The elevator 30 includes a drum 32 around which a wire 31 is wound and a handle 33 that rotationally drives the drum 32. A hook 34 as a connecting portion is attached to the tip of the wire 31. In the elevator 30, the drum 32 is rotated by a rotation of the handle 33 via a drive transmission mechanism (not shown), and the wire 31 wound around the drum 32 is sent out or taken up. As a result, the holding means 20 and the lid 10 connected to the hook 34 at the tip of the wire 31 are moved up and down.

  The support body 40 is a member that supports the elevator 30. The support body 40 is made of a metal material capable of supporting heavy objects, and includes a support column 41 that supports the elevator 30 and a base portion 42 that supports the support column 41. The base 42 is a square-shaped frame that can be disposed around the lid 10 and has a dimension that one side is larger than the diameter dimension of the lid 10. The support column 41 is a member extending upward from the apex position where the base portion 42 is opposed, and the elevator 30 is attached to the upper end of each support column 41. In the present embodiment, the elevator 30 is disposed to face a position slightly higher than the radial dimension of the lid 10. As a result, the lid 10 can be reversed while being lifted up to the vicinity of the upper limit by the elevator 30, so that the lifting heights on both sides in the diameter direction of the lid 10 can be adjusted by the elevator 30, and the lid 10 can be leveled without tilting. It is possible to reverse in a close state.

  Next, the reversing operation of the lid 10 by the reversing device 1 of the manhole lid 10 according to the present invention will be described with reference to FIGS. 4 and 6, the holding portion 24B and the link member 22 are omitted. The lid 10 is usually placed on and covered with a manhole. However, the lid 10 is lifted from the manhole using a known method such as a crane, and moved to another place and placed. Thus, an inverting operation using the inverting device 1 of the present invention is performed.

  First, as shown in FIG. 4, the holding means 20 is attached to the manhole cover 10 placed on the ground. Specifically, the arc member 21 is attached to the edge portion of the lid portion 11 of the lid 10 in the diametrical direction, and the link member opened in an X shape in the screw hole 24C formed in the holding portion 24B of the arc member 21. Screw holes (not shown) formed at each end of 22 are aligned and screwed with bolts 28 (see FIG. 3A). In this embodiment, the lid 10 of the manhole has a rib portion 12 formed on the back side, and the edge of the lid 11 is placed with the edge away from the ground. On the other hand, the arc member 21 can be easily mounted.

  Next, the base portion 42 of the support body 40 is disposed so as to surround the lid 10. And hook 34 attached to the tip of wire 31 of each elevator 30 is connected to ring member 27 of each arc member 21 with which lid 10 was attached, respectively. Then, by rotating the handle 33 of each elevator 30 in a predetermined direction, the lid 10 is raised while winding the wire 31 around the drum 32. Here, since the support shaft 26 is attached to the back side of the holding portion 24A from the center of gravity 13A (see FIG. 3B) of the lid 10, the center of gravity 13A is positioned above the rotation center 26A. . Therefore, as the lid 10 is lifted, reversal by its own weight starts.

  When the lid 10 is lifted, as shown in FIG. 5, the lid 10 is lifted with one end of the edge portion of the lid portion 11 of the lid 10 in contact with the ground. Therefore, the lid 10 gradually rises as the lid 10 rises. When the lid 10 is lifted by substantially the same distance as the radial dimension, the lid 10 is supported by the side surface of the lid portion 11 and is in an upright state. Further, when the lid 10 is raised, the lid portion 11 is separated from the ground, so that the lid 10 is inverted by its own weight.

  As shown in FIG. 6, when the lid 10 is inverted, the center of gravity surface 13 </ b> A (see FIG. 3B) of the lid 10 is positioned below the support shaft 26 that serves as a fulcrum when the lid 10 is lifted. Therefore, it becomes a stable state. With the lid 10 inverted, the handle 33 of the elevator 30 is rotated in the reverse direction to lower the lid 10. In this way, the lid 10 can be inverted and placed on the ground so that the back surface is up, and the back surface of the lid 10 can be inspected and cleaned. At this time, the lid 10 is stably supported by the four support protrusions 25 attached to the arc member 21 of the holding means 20.

  Furthermore, after the inspection of the back surface of the lid 10 is completed, an operation for inverting the lid 10 so as to be in the original front and back state will be described. Similarly to the above, the handle 33 of each elevator 30 is rotated to raise the lid 10. At this time, the lid 10 is lifted in the same posture.

  The lid 10 is manually reversed while each elevator 30 is raised to the upper limit position. At this time, the rotation center 26A of the lid 10 by the support shaft 26 is located in the thickness direction region of the lid 10 and in the vicinity of the center of gravity surface 13A. Therefore, the rotation center 26A is formed outside the thickness direction region of the lid 10. Compared to the case, it can be reversed without requiring a strong force.

  When the lid 10 is inverted to a position where the lid 10 is supported by the side surface of the lid portion 11 and stands upright, the handle of the elevator 30 is rotated in the reverse direction to gradually lower the lid 10. At this time, the standing angle can be gradually reduced in a state where the edge of the lid portion 11 of the lid 10 is in contact with the ground. In this manner, the lid 10 can be surely returned to the original front and back state by being gradually lowered.

  When the lid 10 is returned to the original posture and placed on the ground, the hook 34 is removed from the ring member 27 of the support shaft 26. Further, the bolt 28 is removed, the link member 22 is removed from each holding portion 24 </ b> B, and the arc member 21 is removed from the edge of the lid portion 11 of the lid 10. Then, by a known method such as a crane, the lid 10 is lifted and returned to the original manhole, and the lid is applied.

  As described above, in the manhole cover reversing device 1 according to the present invention, the support shaft 26 as a fulcrum for lifting the cover 10 is provided at a position shifted from the center of gravity surface 13A of the cover 10. At this time, since the support shaft 26 is provided in the holding portion 24 </ b> A that holds the edge of the lid 10, the rotation center 26 </ b> A formed by the support shaft 26 can be disposed in the thickness direction region of the cover portion 11 of the lid 10. it can. Therefore, the center-of-gravity surface 13A of the lid 10 and the rotation center 26A can be arranged close to each other, and the lid 10 can be inverted without requiring a strong force. In particular, since the support shaft 26 is provided on the back side of the center of gravity surface 13A of the lid 10, it can be reversed when the lid 10 is lifted.

  In the above-described embodiment, the support shaft 26 of the holding portion 24A is disposed on the back side of the center of gravity surface 13A of the lid 10. However, the present invention is not limited to this, and the support shaft 26 is disposed on the center of gravity surface 13A of the lid 10. You may arrange | position on the surface side rather than. If it does in this way, when it reverses in the direction which turns the back surface of the lid | cover 10 upwards, it can be reversed manually, and when returning to the original state, it can be reversed by its own weight. Further, the support shaft 26 of the holding portion 24 </ b> A may be arranged so as to coincide with the center of gravity surface 13 </ b> A of the lid 10. In this case, the force required for reversal can be reduced regardless of which side the lid 10 is reversed.

  In the above-described embodiment, an example in which a manual winch is used as the elevator 30 for lifting the lid 10 is shown, but the present invention is not limited to this. For example, an automatic drive winch may be used. A crane used for lifting the lid 10 from the manhole may be used. If a crane is used, the elevator 30 and the support body 40 are unnecessary. Moreover, a crane can be used for both the lifting operation of the lid 10 from the manhole and the reversing operation, and the operation can be effectively advanced. In this case, when the lid 10 is reversed by the crane, in order to connect to the ring member 27 attached to the support shaft 26 of the holding portion 24A of the lid 10, a connecting portion connected to the crane and the ring member 27 are connected. You may use the intermediate member which has a connection part connected with.

  Furthermore, although the link member 22 is configured by connecting a pair of plate-like members so as to be rotatable, the link member 22 is not limited to this and may have a fixed shape. For example, it is good also as X shape which has an edge part which can be connected with the holding | maintenance part 24B.

  Further, the support body 40 that supports the elevator 30 may be configured such that the support column 41 and the base portion 42 can be disassembled and assembled. For example, the elevator 30 and the support column 41 may be separated so that the base 42 can be folded at the apex. As a result, the reversing device 1 can be made compact when not in use, and the device can be easily transported.

  The embodiment of the present invention has been described above, but the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Reversing device 10 Lid 11 Lid part 12 Rib part 13 Center of gravity 13A Center of gravity surface 20 Holding means 26 Support shaft 26A Center of rotation

Claims (6)

A manhole cover reversing device for reversing a manhole cover held by a holding means,
The lid has a disc-shaped lid portion and a rib portion formed below the lid portion,
The holding means has a pair of support shafts that hold the lid portion from the side surface and that form a rotation center at the time of reversal of the lid at a position opposed to the diameter direction of the lid,
An inversion device for a manhole cover, wherein the support shaft is disposed so that the center of rotation is parallel to a center of gravity passing through the center of gravity of the cover and is located within a thickness direction region of the cover. The holding means includes a pair of arc members and a link member that connects the pair of arc members;
Each of the arc members is disposed at an arc-shaped support plate that supports the lid portion in the thickness direction of the lid portion, a central position of the support plate, and a position that is equidistant from the central position. A plurality of holding portions for holding the side surfaces;
The holding portion arranged at the central position is provided with the support shaft, and the holding portion arranged at a position spaced apart from the central position is provided with a connecting hole to which the link member is connected. ,
2. The manhole cover reversing device according to claim 1, wherein the link member connects the pair of arc members so that the support shaft faces the diameter direction of the cover. 3.   3. The manhole cover reversing device according to claim 2, wherein the link member is a pair of plate-like members that are rotatably connected with an intersection as a rotation axis.   4. The manhole cover reversing device according to claim 1, wherein the support shaft is provided on the back surface side of the center of gravity of the lid in the thickness direction of the lid. 5.   The manhole cover reversing device according to any one of claims 1 to 4, further comprising an elevator having a connecting part connectable to the support shaft and capable of moving the cover up and down.   6. The manhole cover reversing device according to claim 5, wherein a plurality of the elevators are arranged at positions higher than a radial dimension of the cover and opposed to each other in a diameter direction of the cover.

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