JP3707786B2 - Locking device for manhole cover - Google Patents

Description

[0001]
[Technical field to which the invention belongs]
The present invention relates to a locking device used for a manhole cover such as a communication groove, a power transmission cable, and a common groove for housing a water and sewage pipe.
[0002]
[Prior art]
As a conventional lid locking device that locks the manhole lid in a closed position with respect to the fixed receiving frame in an unopenable manner, an outer cylinder that penetrates the lid in the vertical direction, and a locking shaft that is rotatably accommodated in the outer cylinder, The locking shaft is fixed to the lower end portion of the locking shaft and is engaged with the receiving portion on the fixed receiving frame side. The operation key is inserted into a key receiving recess formed at the upper end portion of the locking shaft. In some cases, a key code portion is formed at the tip (see, for example, Patent Document 1).
[0003]
In this manhole cover locking device, in order to prevent the key receiving portion of the locking shaft from clogging due to intrusion of muddy water and making it difficult or impossible to insert the key, the shape of the key receiving portion is, for example, substantially triangular. It is formed in a simplified shape.
Because it is designed in consideration of such a special use environment, there is a point that security is inferior as a lock function, and it is not impossible to rotate the lock shaft by forcibly inserting a tool other than the original key. It was.
Further, in the above-described method in which the clasp plate is connected to the lower part of the rotating locking shaft, it is difficult to firmly fix the lid without looseness to the fixed receiving frame.
[0004]
The tightening bolt is accommodated in the vertical hole on the peripheral edge of the lid, and the lid is closed by screwing the screw shaft portion of the tightening bolt protruding from the through hole at the bottom of the vertical hole into the screw hole on the fixed receiving frame side. Has also been proposed in which the upper space of the tightening bolt is closed with a simple lock (see, for example, Patent Document 2).
[0005]
However, in this locking device for lids, the simple lock is configured such that the locking shaft is rotatably fitted in the shaft hole of the lock body, and a clasp plate connected to the lower end portion of the locking shaft is formed on the head of the tightening bolt. Since it is engaged with the lock groove, and a plate-like key is inserted into the split groove formed on the lock shaft and the lock shaft is rotated, there is a disadvantage in security as a lock function. In addition, muddy water or the like may enter the split groove of the locking shaft and cause clogging, and it may be impossible or very difficult to insert the plate-like key.
[0006]
[Patent Document 1]
Japanese Patent No. 3291269 [Patent Document 2]
Japanese Utility Model Publication No. 59-20435 [0007]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to provide a manhole cover locking device which can withstand a poor use environment exposed to rainwater and muddy water and has a necessary and sufficient security function.
[0008]
[Means for Solving the Problems]
A feature of the present invention made to achieve the above-described object is that a cylindrical case 2 fitted into the vertical hole 2 at the peripheral edge of the lid 1 and fixed to the lid 1 and a lower space of the cylindrical case 3 And the screw shaft portion 7 protruding from the through-hole 5 in the bottom wall portion 4 of the cylindrical case 3 is screwed into the screw hole 11 on the fixed receiving frame 10 side, and the lid 1 is moved to the fixed receiving frame 10 in the closed position. The fastening bolt 6 to be fixed and the upper space of the cylindrical case 3 are detachably fitted and cannot be removed from the cylindrical case 3 at a position where the rotational passive portion 9 of the head 8 of the fastening bolt 6 is hidden. A lock unit 12 to be locked and two operating shafts 14 and 15 intersecting each other are provided, and a rotation driving unit 16 fitted to the rotation passive portion 9 of the tightening bolt 6 is connected to one of the operation shafts 14. Locking drive formed at the tip and fitted to the locking shaft 18 of the lock unit 12 The key handle 13 is formed with the portion 17 at the tip of the other operation shaft 15. After the lock unit 12 is removed from the cylindrical case 3 by using the lock driving portion 17, the key handle 13 is driven to rotate. In the manhole cover locking device in which the fastening bolt 6 is rotated by the portion 16 to release the fixation of the cover 1 to the fixed receiving frame 10 .
The lock unit 12 is accommodated in a cylindrical main body 19 that is inserted into the cylindrical case 3 and a non-circular receiving hole in which the locking shaft 18 is fitted and accommodated in the cylindrical main body 19 so as not to rotate but to move in the vertical direction. A locking plate 20 having a central portion 21 formed therein, a spring member 22 that urges the locking plate 20 in the upward direction, and a shaft into which the lower portion of the locking shaft 18 is inserted in the lower space of the cylindrical main body 19. A support body 23 having a hole 24 formed in the center thereof and a side hole 25 of the support body 23 intersecting with the shaft hole 24 are connected to the locking shaft 18 via an interlocking cam mechanism, and the locking shaft 18 is rotated. Correspondingly, a lock body 27 that engages and disengages with the lock groove 26 on the lower inner side surface of the cylindrical main body 19 and a protrusion projecting on the upper inner side surface of the cylindrical main body 19 to restrict the insertion and removal of the key handle 13 from the cylindrical main body 19 It is composed of an insertion / removal restricting body 28,
At the upper part of the locking shaft 18, when engaged with the receiving hole 21 of the locking plate 20, a rotation stopping portion 29 having a non-circular cross section that makes the locking shaft 18 non-rotatable, and a rotation that allows the locking shaft 18 to rotate. The allowance portion 30 is formed up and down, and the lock driving portion 17 of the key handle 13 is formed in a concave shape matching the rotation restraining portion 19 of the lock shaft 18, and the key handle 13 adjacent to the lock drive portion 17 is formed. On the outer peripheral surface of the operation shaft 15, an annular protrusion 32 that contacts the restriction protrusion 31 of the insertion / removal restrictor 28 is formed, and the annular protrusion 32 is formed with a relief groove 33 through which the restriction protrusion 31 can pass. When the operating shaft 15 of the key handle 13 is rotated to a position where the lock body 27 is disengaged from the lock groove 26 of the cylindrical main body 19, the restricting protrusion 31 engages with the lower surface of the annular protrusion 32, and the key handle 13 is removed. it is to become disabled
[0009]
[0010]
[Effects of the Invention]
In the manhole cover locking device of the present invention , an operator who has been given the key handle 13 by the authorized manhole administrator for work such as repair and replacement of the communication cable or inspection, as shown in FIG. The operation shaft 15 on one side is inserted into the lock unit 12, and the lock driving portion 17 of the operation shaft 15 is fitted to the lock shaft 18. After the lock shaft 18 is rotated in the unlocking direction by the key handle 13 to unlock the lock unit 12 with respect to the lid 1, the lock unit 12 is removed from the cylindrical case 3 as shown in FIG. 13.
[0011]
Next, as shown in FIG. 14, another operation shaft 14 of the key handle 13 is inserted into the cylindrical case 3, and the rotation drive unit 16 is fitted to the rotation passive unit 9 of the tightening bolt 6. As shown in FIG. 15, the fastening bolt 6 is rotated in the loosening direction by the key handle 13, and the entire length of the screw shaft portion 7 of the fastening bolt 6 is made to escape from the screw hole 11 of the fixed receiving frame 10. As a result, the fastening of the lid 1 to the fixed receiving frame 10 is released. Thereafter, the lid 1 is opened, and the worker enters the common groove or the like from the manhole and starts a predetermined work.
[0012]
The worker who has finished the required work goes out of the manhole onto the road and closes the lid 1. Then, the operation shaft 14 of the key handle 13 is inserted into the cylindrical case 3, the rotation drive portion 16 of the operation shaft 14 is fitted to the rotation passive portion 9 of the tightening bolt 6, and the tightening bolt 6 is tightened. The lid 1 is fastened and fixed to the fixed receiving frame 10 by rotating and screwing the screw shaft portion 7 of the fastening bolt 6 deeply into the screw hole 11 of the fixed receiving frame 10.
[0013]
Next, the lock unit 12 is inserted into the cylindrical case 3, and the space above the fastening bolt 6 is closed by the lock unit 12. Thereafter, another operation shaft 15 of the key handle 13 is inserted into the lock unit 12, and the lock driving unit 17 of the operation shaft 15 is fitted to the lock shaft 18. The lock shaft 18 is rotated in the locking direction by the key handle 13 to lock the lock unit 12 so that it cannot be removed from the lid 1. Finally, as shown in FIG. 2, the key handle 13 is removed from the lock unit 12, and the worker leaves the site.
[0014]
More specifically, when the lid 1 is closed and locked , the rotation stop portion 29 of the locking shaft 18 is engaged with the receiving hole 21 of the locking plate 20, and the locking shaft 18 is interposed via the locking plate 20. The cylindrical main body 19 is restrained so as not to rotate. Therefore, the lock body 27 that is interlocked with the locking shaft 18 is also held at the locking position where the tip is engaged with the lock groove 26 of the cylindrical main body 19.
[0015]
When the operating shaft 15 on one side of the key handle 13 is inserted into the lock unit 12, the escape groove 33 of the annular protrusion 32 of the operating shaft 15 is inserted / removed and aligned with the restricting protrusion 31 of the restricting body 28, and then the key handle 13 is pushed down. The distal end surface of the locking drive unit 17 of the operation shaft 15 contacts the locking plate 20. When the key handle 13 is further pushed down, the locking plate 20 moves downward against the bias of the spring member 22, and the locking drive unit 17 is fitted to the rotation blocking unit 29 of the locking shaft 18 as shown in FIG. On the other hand, the rotation allowing portion 30 of the locking shaft 18 is engaged with the receiving hole 21 of the locking plate 20. Therefore, the rotation restraint of the locking shaft 18 with respect to the cylindrical main body 19 established through the locking plate 20 is released.
[0016]
When the operation shaft 15 of the key handle 13 is rotated in the unlocking direction at this stage, the locking shaft 18 rotates integrally with the operation shaft 15 around the shaft hole 24 of the support body 23, and the lock body 27 of the interlock cam mechanism. By the action, it slides in the immersion direction and is detached from the lock groove 26 of the cylindrical main body 19. Thereby, the restraint of the lock unit 12 with respect to the lid 1 is released.
When the lock body 27 is detached from the lock groove 26 as described above, the restriction protrusion 31 of the insertion / removal restriction body 28 is engaged with the lower surface side of the annular protrusion 32 of the operation shaft 15, and as shown in FIG. 13. The lock unit 12 is pulled out of the cylindrical case 3 by pulling up the operating shaft 15.
[0017]
Next, as shown in FIG. 14, another operation shaft 14 of the key handle 13 is inserted into the cylindrical case 3, and the rotation drive portion 16 of the operation shaft 14 is fitted to the rotation passive portion 9 of the tightening bolt 6. Then, the key handle 13 is turned to rotate the tightening bolt 6 in the loosening direction, and the entire length of the screw shaft portion 7 of the tightening bolt 6 is escaped from the screw hole 11 of the fixed receiving frame 10 as shown in FIG. As a result, the fastening of the lid 1 to the fixed receiving frame 10 is released. Thereafter, the lid 1 is opened, and the worker enters the common groove or the like from the manhole and starts a predetermined work.
[0018]
After the operation is completed, the lid 1 is closed, and the operation shaft 14 of the key handle 13 is inserted into the cylindrical case 3. The rotation drive portion 16 of the operation shaft 14 is fitted to the rotation passive portion 9 of the tightening bolt 6, the tightening bolt 6 is rotated in the tightening direction, and the screw shaft portion 7 of the tightening bolt 6 is moved to the fixed receiving frame 10. The lid 1 is fastened and fixed to the fixed receiving frame 10 by being deeply screwed into the screw hole 11.
[0019]
Next, the lock unit 12 is inserted into the cylindrical case 3, and the space above the fastening bolt 6 is closed by the lock unit 12. Thereafter, the operation shaft 15 on one side of the key handle 13 is inserted into the lock unit 12, the escape groove 33 of the annular protrusion 32 of the operation shaft 15 is inserted and removed, and the position of the key handle 13 is adjusted with the restriction protrusion 31 of the restriction body 28. When pushed down, the distal end surface of the locking drive portion 17 of the operation shaft 15 contacts the locking plate 20. When the key handle 13 is further pushed down, the locking plate 20 moves downward against the bias of the spring member 22, and the locking drive unit 17 is fitted to the rotation blocking unit 29 of the locking shaft 18, while the locking plate 20 The rotation allowing portion 30 of the locking shaft 18 is engaged with the receiving hole 21. Therefore, the rotation restraint of the locking shaft 18 with respect to the cylindrical main body 19 is released.
[0020]
At this stage, when the operation shaft 15 of the key handle 13 is turned in the locking direction, the locking shaft 18 rotates around the shaft hole 24 of the support body 23, and the lock body 27 slides in the protruding direction by the action of the interlock cam mechanism. Engage with the lock groove 26 of the cylindrical main body 19. As a result, the lock unit 12 is locked to the lid 1 so that it cannot be removed.
In this state where the lock unit 12 is locked, the escape groove 33 of the annular protrusion 32 of the operation shaft 15 is at a position facing the restriction protrusion 31 of the insertion / removal restrictor 28, so that the operation shaft 15 is moved forward. To pull the key handle 13 out of the lock unit 12. Then, carrying the key handle 13, the worker leaves the site.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
In the illustrated embodiment, the rotary passive portion 9 formed on the upper surface of the head 8 of the tightening bolt 6 is constituted by a substantially triangular concave portion with rounded corners, and the operation shaft 14 to be fitted to the concave portion. The rotation drive unit 16 is formed by convex portions having the same shape. A large number of key codes can be set by appropriately changing the cross-sectional shapes of the rotation passive unit 9 and the rotation drive unit 16.
A large-diameter portion 8a is formed in the head 8 of the tightening bolt 6. An annular groove 34 is formed on the inner surface of the intermediate portion of the cylindrical body 19 of the lock unit 12, and an appropriate O- The ring 35 is inserted and held.
[0022]
As shown in FIG. 15, when the screw shaft portion 7 of the tightening bolt 6 escapes from the screw hole 11 of the fixed receiving frame 10 and the head portion 8 floats in the cylindrical main body 19, the outer peripheral surface of the large diameter portion 8a. As a result of the pressure contact with the O-ring 35, the fastening bolt 6 is held in the floating position, and the fastening bolt 6 does not fall off while the lid 1 is opened.
The key handle 13 is formed in a T-shape including the grip portion 36, and a magnet 37 is provided at the tip of the grip portion 36.
[0023]
The upper part of the vertical hole 2 of the lid 1 is formed as a large-diameter hole, and a cap 38 made of rubber or plastic is fitted into the large-diameter hole 2a. A large-diameter stepped portion 39 is formed at the upper end portion of the cylindrical case 3, and the upper end portion of the cylindrical main body 19 of the lock unit 12 protrudes from the large-diameter stepped portion 39, and a plug 40 made of magnetic metal is provided. It is fitted. These caps 38 and plugs 40 provide waterproof and dust-proofing measures for the lock unit 12 and prevent clogging due to intrusion of muddy water. After removing the cap 38, the plug 40 is pulled out of the cylindrical case 3 and the cylindrical main body 19 by being attracted by the magnet 37 of the key handle 13.
[0024]
The inner surface of the locking drive unit 17 at the tip of the operation shaft 15 is formed in a non-circular shape in which two adjacent sides of a regular hexagon are arcuate, and the head of the locking shaft 18 into which the locking shaft 17 is fitted, that is, the rotation restraint portion. 29 is also formed in the same shape. The receiving hole 21 of the locking plate 20 has the same shape. The rotation allowing portion 30 formed below the rotation stopping portion 29 is formed in a circular cross section that is inscribed in the receiving hole 21. A large number of key codes can be set by variously changing the cross-sectional shape of the locking drive unit 17 and the like.
[0025]
The fixing plate 40 fitted in the middle part of the cylindrical case 32 is fixed to the cylindrical case 3 by welding. By screwing a fixing screw 42 into the bottom wall portion 4 of the vertical hole 2 through the receiving groove 41 of the fixing plate 40, the cylindrical case 3 is restrained against rotation with respect to the lid 1. A fastening nut 44 is screwed into the lower end screw portion 43 of the cylindrical case 3, and the cylindrical case 3 is fixed to the lid 1 by sandwiching the lid 1 between the fixing plate 40 and the fastening nut 44. .
[0026]
A locking groove 45 is formed in the axial direction on the inner side surface of the cylindrical main body 19 of the lock unit 12, and a blocking projection 46 is formed on the outer side surface of the locking plate 20. When the stop projection 46 is engaged with the stop groove 45, the lock plate 20 is movable in the vertical direction with respect to the cylindrical main body 19 and is restricted so as not to rotate.
A retaining pin 48 is inserted into the annular groove 47 on the outer surface of the support body 23 through the side wall portion of the cylindrical main body 19, and the support body 23 is attached to the cylindrical main body 19 so as to be rotatable and unremovable. ing.
[0027]
A drive cam projection 49 is projected from the lower surface of the locking shaft 18 at an eccentric position, and a passive cam groove 50 into which the drive cam projection 49 is inserted is formed in the plate-like lock body 27 in the transverse direction. When the locking shaft 18 is rotated, the drive cam projection 49 pushes the inner surface of the passive cam groove 50, so that the lock body 27 slides in a direction perpendicular to the axis of the locking shaft 28, and the locking groove of the cylindrical case 3 is moved. 26 is disengaged.
The spring member 22 that urges the locking plate 20 in the upward direction is constituted by a compression coil spring, and is inserted between the upper surface of the support body 23 and the lower surface of the locking plate 20.
The arrangement interval and the number of the restraining projections 46 of the locking plate 20 and the width dimension of the restraining projection 46 are changed, the number of the annular projections 32 of the operation shaft 15 and the thickness dimension of the annular projection 32 in the axial direction are changed. By doing so, it is possible to change the setting of a large number of key codes.
In this manhole cover locking device, the cylindrical case 3 is inserted and fixed in the vertical hole 2 of the cover 1, and the screw shaft portion 7 of the fastening bolt 6 accommodated in the cylindrical case 3 is used as the bottom wall portion 4 of the cylindrical case 3. The lid 1 is fastened to the fixed receiving frame 10 by screwing the screw shaft portion 7 into the screw hole 11 on the fixed receiving frame 10 side, so that it vibrates by contact with the passing vehicle. Does not generate rattling noise.
Further, the lock unit 12 is inserted into the upper space of the cylindrical case 3 to conceal the rotational passive portion 9 of the head 8 of the tightening bolt 6, and the lock unit 12 is locked to the cylindrical case 3 so that it cannot be removed. Since the lock cannot be effectively released without the key handle 13 having the predetermined lock driving portion 17 fitted to the lock shaft 18 of the lock unit 12, it has a necessary and sufficient security function. .
[0028]
[0029]
【The invention's effect】
In the lid locking device of the present invention, the locking plate 20 is accommodated in the cylindrical main body 19 of the lock unit 12 so as not to rotate and to be movable in the vertical direction, and the locking plate 20 is biased in the upward direction by the spring member 22. Then, the lower part of the locking shaft 18 is inserted into the shaft hole 24 of the support body 23 accommodated in the lower space of the cylindrical main body 19, and the lock body 27 is inserted into the side hole 25 of the support body 23 intersecting with the shaft hole 24, A lock body 27 is connected to the locking shaft 18 via the interlock cam mechanism, and the insertion / removal body 28 protruding from the upper inner surface of the tubular body 19 restricts the insertion / removal of the key handle 13 with respect to the tubular body 19. Thus, when engaged with the non-circular receiving hole 21 of the locking plate 20, a rotation stopping portion 29 that makes the locking shaft 18 non-rotatable is formed on the upper portion of the locking shaft 18 and engaged with the receiving hole 21. Rotation permitting the locking shaft 18 to rotate A portion 30 is formed on the lower side of the rotation restraining portion 29, an annular protrusion 32 is formed on the outer peripheral surface of the operation shaft 15 of the key handle 13 and abuts against the restriction protrusion 31 of the insertion / removal restrictor 28, and the restriction protrusion 31 is formed on the annular protrusion 32. Is formed so that it can be used with high reliability without causing clogging due to sand and mud particles even in a poor use environment exposed to rainwater and muddy water, and has a necessary and sufficient security function. It will be a thing.
Further, in a state where the lock body 27 is detached from the lock groove 26, the lock protrusion unit 12 is engaged with the lower surface side of the annular protrusion 32 of the operation shaft 15 because the restriction protrusion 31 of the insertion / removal restriction body 28 is engaged with the operation shaft 15. By pulling up, the cylindrical case 3 is immediately pulled out, and the workability is excellent.
[Brief description of the drawings]
FIG. 1 is a plan view of a manhole cover locking device in use according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along line AA in FIG.
3 is a front view of a key handle used in the lid locking device of FIG. 1. FIG.
4 is an enlarged front view of a locking drive unit in the key handle of FIG. 3. FIG.
FIG. 5 is a bottom view of a lock driving unit in the key handle of FIG. 3;
6 is a bottom view of a rotation driving unit in the key handle of FIG. 3. FIG.
7 is a plan view of a locking shaft used in the lid locking device of FIG. 1. FIG.
8 is a front view of the locking shaft of FIG. 7. FIG.
9 is a plan view of a locking plate used in the lid locking device of FIG. 1. FIG.
10 is a front view of the locking plate of FIG. 9. FIG.
11 is a longitudinal sectional view showing a state in which a lock driving unit of a key handle is inserted into a lock unit in the lid locking device of FIG. 1. FIG.
12 is a longitudinal sectional view when the key handle is pushed down from the state of FIG.
13 is a longitudinal sectional view when the key handle is turned from the state of FIG. 12 and the lock unit is removed from the cylindrical case. FIG.
14 is a longitudinal sectional view of the key handle rotation drive unit inserted from the state shown in FIG.
15 is a longitudinal sectional view when the key handle is turned from the state shown in FIG. 14 to raise the fastening bolt.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cover 2 Vertical hole 3 Cylindrical case 4 Bottom wall part 5 Through-hole 6 Fastening bolt 7 Screw shaft part 8 Head 9 Rotation passive part 10 Fixed receiving frame 11 Screw hole 12 Locking unit 13 Key handle 14 Operation shaft 15 Operation shaft 16 Rotation drive unit 17 Locking drive unit 18 Locking shaft 19 Cylindrical body 20 Locking plate 21 Receiving hole 22 Spring member 23 Support body 24 Shaft hole 25 Side hole 26 Locking groove 27 Locking body 28 Insertion / removal restricting body 29 Rotation restraining part 30 Rotation allowance Part 31 Restriction protrusion 32 Annular protrusion 33 Relief groove

Claims (1)

A cylindrical case 2 fitted into the vertical hole 2 at the peripheral edge of the lid 1 and fixed to the lid 1, and accommodated in a lower space of the cylindrical case 3, from a through hole 5 in the bottom wall portion 4 of the cylindrical case 3 The protruding screw shaft portion 7 is screwed into the screw hole 11 on the fixed receiving frame 10 side, and can be inserted into and removed from the tightening bolt 6 for fixing the lid 1 to the fixed receiving frame 10 in the closed position and the upper space of the cylindrical case 3. And a lock unit 12 that is locked to the cylindrical case 3 so that it cannot be removed at a position where the rotational passive portion 9 of the head 8 of the clamping bolt 6 is concealed, and two operating shafts 14 that intersect each other. , 15 is formed at the tip end portion of one operation shaft 14 and fitted to the locking shaft 18 of the lock unit 12. A key handle 13 in which a locking drive unit 17 is formed at the tip of the other operation shaft 15. After the lock unit 12 is removed from the cylindrical case 3 by using the locking drive unit 17, the fastening bolt 6 is rotated by the rotation drive unit 16 of the key handle 13 to release the fixation of the lid 1 to the fixed receiving frame 10. In the manhole cover locking device designed to
The lock unit 12 is accommodated in a cylindrical main body 19 that is inserted into the cylindrical case 3 and a non-circular receiving hole in which the locking shaft 18 is fitted and accommodated in the cylindrical main body 19 so as not to rotate but to move in the vertical direction. A locking plate 20 having a central portion 21 formed therein, a spring member 22 that urges the locking plate 20 in the upward direction, and a shaft into which the lower portion of the locking shaft 18 is inserted in the lower space of the cylindrical main body 19. A support body 23 having a hole 24 formed in the center thereof and a side hole 25 of the support body 23 intersecting with the shaft hole 24 are connected to the locking shaft 18 via an interlocking cam mechanism, and the locking shaft 18 is rotated. Correspondingly, a lock body 27 that engages and disengages with the lock groove 26 on the lower inner side surface of the cylindrical main body 19 and a protrusion projecting on the upper inner side surface of the cylindrical main body 19 to restrict the insertion and removal of the key handle 13 from the cylindrical main body 19 It consists of an insertion / removal restriction body 28,
At the upper part of the locking shaft 18, when engaged with the receiving hole 21 of the locking plate 20, a non-circular cross-section rotation restraining portion 29 that makes the locking shaft 18 non-rotatable, and the locking shaft 18 is rotatable. The rotation permitting portion 30 is formed vertically, and the lock driving portion 17 of the key handle 13 is formed in a concave shape that matches the rotation stopping portion 19 of the lock shaft 18, and the key handle 13 adjacent to the lock drive portion 17 is formed. An annular protrusion 32 is formed on the outer peripheral surface of the operation shaft 15 so as to abut against the restriction protrusion 31 of the insertion / removal restricting body 28, and a relief groove 33 through which the restriction protrusion 31 can pass is formed in the annular protrusion 32. When the operation shaft 15 of the key handle 13 is rotated to a position where the lock body 27 is disengaged from the lock groove 26 of the cylindrical main body 19, the restricting protrusion 31 engages with the lower surface of the annular protrusion 32, and the key handle 13 is moved. that to disable sampling Manhole lid locking device for the butterflies.

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