JP2001329555A - Lock device for manhole cover - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent ingress of rainwater into a manhole through an manipulation port of a manhole cover and prevent a leakage of odor in the manhole. SOLUTION: An elevating body 32 provided with a shielding cover part 33 shielding the operation port of the manhole cover 2 and an inclined fringe 36 is provided at a lower part position of the manipulation port so as to rise and fall. A lock piece 39 provided with an engaging end 41 opposing to a locking face 40 of a lid receive frame 1 and an inclined receive fringe 42 inclined in the same direction as the inclined fringe 36 of the elevating body 32 is provided so as to advance and retreat. The lock piece 39 is usually urged onto a cover receive frame 1 side is held at a lock position where the engaging end 41 opposes to the locking face 40, and is retracted to a refuge position through pressing action of the inclined fringe 36 due to pressing-down operation of the elevating body 32. When the lock piece 39 is at the lock position, the elevating body 32 is raised through pressing action of the inclined fringe 36 by the inclined receive fringe 42 of the lock piece 39 and is held at a shield position to shield the operation port from below by the shielding cover part 33 of the elevating body 32.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lock device for preventing unnecessary opening of a manhole cover.

[0002]

2. Description of the Related Art A manhole cover for covering an opening of a manhole is attached to a cover receiving frame provided in the opening, but when the manhole cover is unnecessarily opened due to mischief or the like, the opened manhole is opened. In such a case, tires of a person or a car may fall and cause a serious accident. For this reason, various lock devices for preventing unnecessary opening of the manhole cover have been proposed.

FIG. 11 and FIG. 12 show that the applicant of the present application
1 shows a conventional locking device proposed in Japanese Patent Publication No. 4045. This is the manhole cover b attached to the cover receiving frame a.
A rotating piece g having a lever portion e protruding toward the operation port c and a locking rod portion f hanging downward is formed on the periphery of the operation port c. Is rotatably locked to the lower side of the side via a rotation shaft d, and the lever portion e is urged upward by a spring h attached to the rotation piece g, so that the lever portion e is moved downward to the operation port c. From the front, and
A lock piece n having an engagement end k facing downward from a locking surface j formed on the inner surface of the lid receiving frame a and having a linking hole m into which the locking rod f is inserted is formed in a front-rear direction. It is movably supported on the lower surface of the manhole cover b.

In the lock device described above, the lock piece n linked to the locking rod f is pushed by the spring h so that its engaging end k is fixed to the locking surface of the lid receiving frame a. j is held at the lock position facing from below, so that the engaging end k can be kept at the locking surface j even if the manhole cover b is lifted as it is.
To make it impossible to open, and the manhole cover b
Is released, a tool such as a bur is inserted into the operation port c from above, and the lever e is pressed down, whereby the rotating piece g rotates against the bias of the spring h, and The lock piece n linked to the locking rod f of the moving piece g is retracted to the retracted position, so that the locked state can be released.

[0005]

By the way, in recent years, with respect to manhole covers, due to the problem of treatment capacity in sewage treatment facilities, the amount of rainwater flowing into the sewer pipes from the manhole covers during rainfall can be reduced as much as possible. Things are desired. Thus, in the manhole cover b provided with the lock device having the above-described conventional configuration, in order to rotate the rotating piece g, the lever portion e of the rotating piece g and the inner peripheral edge of the lid receiving frame a are used. , A gap s (see FIG. 11) is required, and the operation port c cannot be shielded by the lever portion e. For this reason,
Rainwater easily flows in from the gap s, and this configuration cannot meet the demand for reducing the amount of rainwater flowing from the manhole cover b as much as possible. Further, there is a problem that the odor in the manhole leaks from the gap s, and furthermore, the recess p is formed by the operation port c and the lever portion e located below the operation port c.
There is also a problem that the mud easily accumulates in the concave portion p, and when solidified, removal of the mud takes time and effort.

An object of the present invention is to provide a locking device for a manhole cover which can solve the problems of the conventional configuration.

[0007]

According to the present invention, there is provided a manhole cover having an operation port on a peripheral edge thereof, the manhole cover being attached to a lid receiving frame, a shielding cover for shielding the operation port from below, and a lower rear surface having a lower end. An elevating body having an inclined edge inclined toward the upper rear end, and being held at a lower position of the operation port of the manhole cover so as to be able to ascend and descend, and opposing a locking surface formed on an inner surface of the lid receiving frame from below. An engaging end, and an inclined receiving edge that is inclined in the same direction as the inclined edge of the elevating body and supports the inclined edge. A locking piece which is held at a locking position facing the locking surface from below, and which is capable of moving back and forth in a front-rear direction to retreat to a retracted position through a pressing action of an inclined edge by a pushing-down operation of the elevating body. It is a locking device for a manhole cover.

In this configuration, when the lock piece is at the lock position where the lock piece is urged toward the lid receiving frame by the urging means, the lifting / lowering body having the inclined edge supported by the inclined receiving edge of the lock piece includes the tilt receiving member. The state is maintained at the shielding position raised by the pressing action of the inclined edge by the edge, and the operation port is shielded from below by the shielding lid of the elevating body. Thereby, inflow of rainwater from the operation port can be prevented, and leakage of odor in the manhole can be prevented. Here, the shielding state of the operation port by the shielding lid part is not a completely sealed state, and there is some gap required for raising and lowering the lifting body. Therefore, in the present invention, preventing the inflow of rainwater and the leakage of odor from the operation port means that the amount of inflow of rainwater and the amount of leakage of odor are extremely small.

In the above structure, the shielding lid has a planar shape substantially equal to the planar shape of the operation port, and a convex surface fitted into the operation port from below and substantially flush with the upper surface of the manhole cover. An upwardly projecting configuration may be proposed. in this way,
By providing the shielding lid with a convex surface that fits into the operation port, it is possible to prevent intrusion of mud into the operation port and solidification thereof.

Further, in the above configuration, a configuration may be proposed in which a notch is provided below the rear end of the lock piece so that the engagement end can be tilted upward in a biased state toward the lid receiving frame. As described above, by providing the cutout portion at the lower rear end of the lock piece, when attaching the opened manhole cover to the lid receiving frame, when the manhole lid is dropped into the lid receiving frame, the lock which comes into contact with the lid receiving frame is provided. The engagement end side of the piece can be inclined upward, and the manhole lid can be easily attached to the lid receiving frame by its own weight without the lock piece being hooked on the lid receiving frame.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the lid receiving frame 1 provided at the opening of the manhole is formed in an annular shape. The lid receiving frame 1 is formed in a circular shape with an outer diameter substantially equal to the inner diameter of the lid receiving frame 1. The manhole cover 2 is detachably attached. As shown in FIG. 2, the inner peripheral edge of the lid receiving frame 1 is a tapered edge 3 inclined downward and narrowed, and the outer peripheral edge of the manhole lid 2 is also a tapered edge inclined in the same direction. . Accordingly, when the manhole cover 2 is fitted into the cover receiving frame 1, the tapered edges of the manhole cover 2 are not in contact with each other to form a gap, and the manhole cover 2 is supported by the tapered edge 3 of the cover receiving frame 1. 2 can be prevented from falling. The manhole cover 2 is not provided with any small holes for ventilation that penetrate the front and back surfaces as seen in conventional products.

An operation port 4 is formed at a part of the peripheral edge of the manhole cover 2, and a lock device A described later is provided at a lower position of the operation port 4. Further, a connecting device B for connecting the manhole cover 2 to the cover receiving frame 1 is provided at a position 180 ° different from the operation port 4.

As shown in FIG. 2, the coupling device B has a substantially S-shaped lock lever 6 suspended from the lower surface of the peripheral edge of the manhole cover 2 via the support shaft 5 and a projection from the inner peripheral edge of the lid receiving frame 1. The lock lever 6 is inserted through a long hole 8 in the radial direction formed in the lock portion 7, and a retaining rod 9 protruding to both sides at a lower end thereof. The manhole cover 2 is not allowed to escape from the long hole 8, thereby connecting the manhole cover 2 to the cover receiving frame 1. Further, the lock lever 6 has a projection 10 facing the lower edge of the locking portion 7 from below in a hanging state due to its own weight, and lifts the vicinity of a position immediately above the lock lever 6 of the manhole cover 2. Even so, the projection 10 abuts on the lower edge of the locking portion 7 to prevent the manhole cover 2 from being opened by an operation other than the normal opening operation.

Next, the main part of the present invention will be described with reference to FIGS. Operation port 4 formed on the periphery of manhole cover 2
The holder member 11 of the lock device A is located at the lower position of
It is integrally formed on the lower surface of the manhole cover 2. As shown in FIGS. 3 and 4, the holder member 11 includes a pair of right and left side walls 12, 12 extending in the radial direction and provided on both sides of the operation port 4.
An L-shaped guide plate 13 is inserted between the side walls 12 at a middle position near the rear.
At the front of the side walls 12, 12, front walls 14, 14, which are integral with the peripheral wall 2a of the manhole cover 2, are connected, and an upper operation port 4 is provided between the front walls 14, 14. An opening 15 having the same width as that of the operation port 4 is opened vertically. Also, the inner wall surfaces 16, 16 of the front walls 14, 14
The front wall surface 17 of the guide plate 13 opposed thereto is an inclined surface parallel to the tapered edge 3 of the lid receiving frame 1 as shown in FIG. And the inner wall surface 1 of the front walls 14, 14
6, 16 and the front wall surface 17 of the guide plate portion 13 and the inner wall surfaces of the left and right side walls 12, 12 form a vertical guide gap 19 surrounded in the front, rear, left and right directions.

The lower part of the holder member 11 has a structure shown in FIG.
The cover plate 20 is fixed by bolts 21 and 21 as shown in FIG. The cover plate 20, as shown in FIG.
Engagement projections 22, 22 are formed on the right and left sides of the front end thereof, and a spring receiving wall 24 provided with a spring receiving projection 23 projecting forward is formed on the rear end thereof.
At the left and right side edges of the cover plate 20, insertion holes 26, 26 for bolts 21, 21 are formed at positions corresponding to the screw holes 25, 25 formed on the lower surface of the side walls 12, 12, of the holder member 11. I have. The locking projections 22 are engaged with the cutouts 27 formed on the front lower surfaces of the side walls 12 of the holder member 11, and the front edges 28 of the spring receiving wall 24 are engaged. The bolts 21, 21 inserted into the insertion holes 26, 26 are engaged with the screw holes 25, 25 of the holder member 11, respectively, while being engaged with the rear edges 29, 29 of the side walls 12, 12 of the holder member 11. By
The cover plate 20 is fixed to the holder member 11. Then, as shown in FIG. 4, when the cover plate 20 is fixed to the holder member 11, the cover plate 2
0, the inner wall surfaces of the left and right side walls 12, 12, and the lower wall surface 30 of the guide plate portion 13 form a guide gap 31 in the front-rear direction, which is vertically and horizontally surrounded.

As shown in FIG. 5, an elevating body 32 is fitted in the guide space 19 so as to be able to move up and down. The lifting body 32
As shown in FIG. 3, a shielding lid 33 for shielding the operation port 4 from below is provided at an upper portion thereof, and the shielding lid 33 is
A pair of side plates 34, 34 extending downward from both left and right ends of the
Each has. A convex surface 35 having a plane shape substantially equal to the planar shape of the operation port 4 is formed on the shielding lid portion 33 so as to project upward, and the convex surface 35 is fitted into the operation port 4 from below and the upper surface of the manhole cover 2 is formed. The height dimension is set so as to be substantially flush. An inclined edge 36 that is inclined from the lower end toward the upper rear end is formed on the lower rear surface of the elevating body 32. That is, the side plate portions 34, 34 are each formed with an inclined surface inclined from the lower end toward the upper rear end, so that the inclined surface is the inclined edge 36. The front end faces 37, 37 of the side plates 34, 34 and the side plates 3
4, 34 and the rear end face 38 of the shielding lid 33 are inclined surfaces parallel to the tapered edge 3 of the lid receiving frame 1, and the rising surfaces before and after the convex surface 35 formed on the shielding lid 33 are also formed. The lid receiving frame 1 has an inclined surface parallel to the tapered edge 3. Thus, the elevating body 32 fitted in the guide gap 19 can be moved up and down in parallel with the tapered edge 3 of the lid receiving frame 1.

As shown in FIG. 5, a lock piece 39 is fitted in the guide gap 31 so as to be able to advance and retreat in the front-rear direction. The lock piece 39 has, at the front end, an engagement end 41 that opposes a locking surface 40 formed on the inner surface of the lid receiving frame 1 from below, and is further inclined in the same direction as the inclined edge 36 of the elevating body 32. And an inclined receiving edge 42 for supporting the inclined edge 36. That is, as shown in FIG.
The lifting piece 3 is provided on the left and right side edges of the lock piece 39.
The inclined surfaces of the side plates 34, 34 formed as the two inclined edges 36 can be mounted. Lock piece 3
9, a spring receiving projection 43 facing the spring receiving projection 23 is provided to project rearward.
A coil spring 44 whose both ends are fitted to the outside of the lock pieces 39 and 43 is interposed between the rear end of the lock piece 39 and the spring receiving wall 24 in a compressed state. Then, the lock piece 39 is urged toward the lid receiving frame 1 by the urging means including the coil spring 44, and the locking piece 39 is engaged with the front engaging end 41 of the lid receiving frame 1 as shown in FIG. It is held at a lock position facing the stop surface 40 from below.

Further, as described above, the lock piece 39 is attached to the lid receiving frame 1.
Biasing the locking piece 39 toward the inclined receiving edge 4
The lifting body 32 on which the inclined edge 36 is mounted is raised by the pressing of the inclined edge 36 by the inclined receiving edge 42 so that the shielding lid 33 shields the operation port 4 from below. It is made to hold.

Next, the procedure for assembling the lock device A having the above configuration will be described. In order to assemble the lock device A from the disassembled state shown in FIG. 3, first, the manhole cover 2 is turned upside down, and the elevating body 32 which is turned upside down is dropped into the guide space 19 of the holder member 11 and mounted. Enter. Next, the lock piece 39 is placed on the cover plate 20, and both ends of the coil spring 44 are fitted to the spring receiving projections 23 and 43, and the coil spring 44 is attached to the rear end of the lock piece 39 and the spring support of the cover plate 20. It is interposed between the wall 24. Then, the cover plate 20 and the lock piece 39 are held in a state where the lock piece 39 is retracted so as to compress and contract the coil spring 44, and in this state, the cover plate 20 is turned upside down and applied to the holder member 11 from above. At this time, the locking projections 22, 22 of the cover plate 20
By engaging the front edges 28, 28 of the spring receiving wall 24 with the cutouts 27, 27 of the side walls 12, 12 of the holder member 11, and the rear edges 29, 29 of the side walls 12, 12, respectively. The cover plate 20 is positioned so as to be immovable in the front-rear direction, so that the insertion holes 26, 26 of the cover plate 20 and the screw holes 25, 25 of the holder member 11 can be easily matched. Further, by applying the lock piece 39 to the holder member 11 in a state where the lock piece 39 is retracted so as to compress and contract the coil spring 44 as described above, the narrow width front end portion of the lock piece 39 is lifted and lowered. The lock piece 39 can be easily inserted between the left and right side plate portions 34, 34 of the body 32. When the lock piece 39 is released in this state, the lock piece 39 is pushed forward by the bias of the coil spring 44, and the lock piece 39 is pushed out. A state is obtained in which the inclined receiving edge 42 of the piece 39 contacts the inclined edge 36 of the elevating body 32. Then, the cover plate 20 is fixed to the holder member 11 by inserting the bolts 21 and 21 into the insertion holes 26 and 26 and screwing them into the screw holes 25 and 25, respectively, and the assembly is completed. As a result, the locking device A can be assembled very easily.

Here, a lock device having a conventional configuration (FIG. 11, FIG.
At the time of assembling, the coiled springs h, h are loosely fitted to the left and right rotating shafts d, d of the rotating piece g, and the rotating shafts d, d Must be fitted into the recessed portions t, t formed in the manhole cover b from the peripheral edge of the manhole cover b to the back. At this time, the springs h, h generate elastic force. In this state, one end of each of the springs h, h is caught on the lower surface of the manhole cover b, causing sliding resistance, which makes the fitting operation of the rotating piece g difficult. On the contrary,
As described above, the lock device A of the present invention can be assembled very easily.

In such a configuration, the lock device A is configured such that the lock piece 39 is urged toward the lid receiving frame 1 by the urging means including the coil spring 44 in a normal state.
As shown in FIG. 5, the engagement end 41 is connected to the locking surface 40 of the lid receiving frame 1.
And is pushed out from below to the opposing lock position. Thus, even if the manhole cover 2 is lifted, the engaging end 41 abuts on the locking surface 40, so that unnecessary opening due to mischief or the like is prevented. Here, since an appropriate clearance is provided between the engagement end 41 of the lock piece 39 and the locking surface 40 of the lid receiving frame 1, when an internal pressure such as gas is generated in the manhole, The gas can be vented by the upward movement of the manhole cover 2 so that the cover receiving frame 1 can be prevented from being damaged.

As described above, when the lock piece 39 is at the lock position where the lock piece 39 is urged toward the lid receiving frame 1 by the urging means including the coil spring 44, the inclined edge 36 is formed on the inclined receiving edge 42 of the lock piece 39. The supported elevating body 32 rises through the pressing action of the inclined edge 36 by the inclined receiving edge 42 and is held at the shielding position, so that the operation port 4 is closed by the shielding lid 33 of the elevating body 32. A state of shielding from below is obtained. Thereby, inflow of rainwater from the operation port 4 can be prevented, and leakage of odor in the manhole can be prevented. Further, since the convex surface 35 projecting upward from the shielding lid portion 33 is fitted into the operation port 4 in a state substantially flush with the upper surface of the manhole cover 2, the intrusion of mud into the operation port 4 and The caking can be prevented.

When the manhole cover 2 is to be opened, as shown in FIG.
Is inserted into the operation port 4 and the elevating body 3
2, the locking piece 39 is retracted to the retreat position against the bias of the coil spring 44 by the pressing action of the inclined edge 36 by the inclined edge 36 of the elevating body 32,
Of the locking surface 40 is released. Then, while maintaining this released state, the operating head 45 of the special tool 46 is rotated by approximately 90 °, and both ends thereof are brought into contact with the back side of the rim of the operating port 4 and pulled up, so that the manhole cover is raised. The peripheral portion where the second lock device A is located can be lifted. Thereafter, the manhole cover 2 is pulled outwardly on the side opposite to the connecting device B, and the lock lever 6 is pulled out to release the lock, and the manhole cover 2 is turned horizontally around the lock lever 6. The manhole cover 2 can be opened by a predetermined operation.

When the manhole cover 2 is to be reattached to the lid receiving frame 1, the peripheral portion on the connecting device B side is fitted first, and then the peripheral portion on the locking device A side is dropped into the lid receiving frame 1. With this lowering, the curved chamfered portion 47 formed on the lower surface of the distal end of the engagement end 41 of the lock piece 39 is pressed by the tapered edge 3 of the lid receiving frame 1, and the lock piece 39 is moved to the retracted position. When the engagement end 41 passes through the tapered edge 3, the lock piece 39 is pushed forward by the bias of the coil spring 44, and the engagement end 41 is automatically moved to the lock position where the engagement end 41 faces the engagement surface 40 from below. It returns. Further, in such a locked state, the lifting / lowering body 32 rises through the pressing action of the inclined edge 36 by the inclined receiving edge 42 of the lock piece 39 and is held at the shielding position.

FIGS. 7 and 8 show a second embodiment. In this embodiment, the convex surface 35 (see FIG. 3) formed on the shielding lid 33 of the elevating body 32 in the first embodiment is removed. It was done. Other configurations are the same as the first embodiment,
The same portions are denoted by the same reference numerals, and redundant description will be omitted.
Even in this configuration, when the lock piece 39 is in the lock position where the lock piece 39 is urged toward the lid receiving frame 1 by the urging means including the coil spring 44, as shown in FIG. The operation port 4 can be shielded from below. Thereby, inflow of rainwater from the operation port 4 can be prevented, and leakage of odor in the manhole can be prevented.

FIGS. 9 and 10 show a third embodiment. In this embodiment, the locking piece 39 described in the first embodiment is engaged with the lower end of the locking piece 39 in a biased state toward the lid receiving frame 1 side. A notch 48 is provided to enable the upper end 41 to be inclined upward.
The notch 48 is formed by chamfering the lower end of the lock piece 39 in a straight or curved shape,
In the example shown in FIG. 9A, the starting point of the chamfering process on the lower surface side of the lock piece 39 is located on a vertical line passing through the ridge 49 between the front wall surface 17 and the lower wall surface 30 of the guide plate portion 13. . Thereby, as described later, the engagement end 41 side of the lock piece 39 can be inclined upward with the ridge 49 as a fulcrum. As shown in FIG. 10, if an appropriate gap u is provided between the upper surface of the lock piece 39 and the lower wall surface 30 of the guide plate 13, the starting point of the chamfering passes through the ridge 49. Lock piece 3 even after the perpendicular
9 can be inclined upward. Other configurations are the same as those of the first embodiment, and the same portions are denoted by the same reference numerals, and redundant description will be omitted.

In this structure, when the opened manhole cover 2 is to be reattached to the lid receiving frame 1, the peripheral portion on the connecting device B side (see FIG. 2) is fitted first, and then the peripheral portion on the locking device A side. When the part is dropped into the lid receiving frame 1, as described above,
Normally, the curved chamfered portion 47 formed on the lower surface of the distal end of the engagement end 41 of the lock piece 39 is pressed by the tapered edge 3 of the lid receiving frame 1, and the lock piece 39 retreats to the retracted position. Due to some operation resistance such as rusting at the sliding part or gravel biting, the lock piece 39 does not retreat smoothly,
The engagement end 41 of the lock piece 39 may be hooked on the tapered edge 3 of the lid receiving frame 1. In such a case, a notch 48 that allows the engagement end 41 to be tilted upward is provided below the rear end of the lock piece 39, so that the ridge 49 as shown in FIG. With the upper surface of the lock piece 39 abutting on the fulcrum, the engagement end 41 side of the lock piece 39 is inclined upward, and the taper edge 3 can be passed in this state. When the engagement end 41 passes through the tapered edge 3, the lock piece 39 is pushed forward by the urging of the coil spring 44, and the engagement end 41 is moved to the engagement surface 40 as shown in FIG.
Automatically returns to the lock position facing from below. Thus, the manhole cover 2 can be easily attached to the lid receiving frame 1 by its own weight without the locking piece 39 being hooked on the lid receiving frame 1.

[0028]

According to the present invention, as described above, the shielding lid 33 for shielding the operation port 4 of the manhole lid 2 from below and the inclined edge 36 inclined from the lower end toward the upper rear end on the lower rear surface. The elevating body 32 provided is provided at the lower part of the operation port 4 of the manhole cover 2 so as to be able to move up and down, while the engaging end 41 facing the locking surface 40 formed on the inner surface of the lid receiving frame 1 from below, and A locking piece 39 which is provided with an inclined edge 36 of the body 32 and an inclined receiving edge 42 which is inclined in the same direction to support the inclined edge 36, and which is provided so as to be able to advance and retreat in the front-rear direction, is normally covered by a biasing means by a biasing means. The engaging end 41 is urged toward the receiving frame 1 to hold the engaging end 41 at the locked position facing the engaging surface 40 from below, and is moved to the retracted position through the pressing operation of the inclined edge 36 by the pushing-down operation of the elevating body 32. Because it is a manhole cover lock device that is made to retreat When the lock piece 39 is in the locked position of the steady, elevating body 32, inclined 受縁 4 of the locking piece 39
The operation port 4 can be shielded from below by the shield lid 33 of the elevating body 32 ascending by the pressing action of the inclined edge 36 by the 2 and held at the shielding position. This allows
The inflow of rainwater from the operation port 4 can be prevented, and the leakage of odor in the manhole can be prevented.

The shielding cover 33 has a convex surface 35 which has a plane shape substantially equal to the plane shape of the operation port 4 and which is fitted into the operation port 4 from below and is substantially flush with the upper surface of the manhole cover 2. If it projects upward, in addition to the above-mentioned operation, it is possible to solve the conventional problem that the mud does not accumulate in the operation port 4 and it takes time to remove the solidified mud. An excellent effect that can be obtained is obtained.

Furthermore, if a notch 48 is provided below the rear end of the lock piece 39 so as to allow the engagement end 41 to be tilted upward while being biased toward the lid receiving frame 1, the opened manhole cover 2 can be opened.
When the manhole cover 2 is dropped into the cover receiving frame 1 when the cover 3 is attached to the cover receiving frame 1,
9 can be inclined upward, and the lock piece 39 can be easily attached to the lid receiving frame 1 by its own weight without being caught by the lid receiving frame 1. is there.

[Brief description of the drawings]

FIG. 1 is a plan view of a lid receiving frame and a manhole lid of the first embodiment attached to the lid receiving frame.

FIG. 2 is a side sectional view showing a construction state of a manhole cover provided with the lock device according to the first embodiment.

FIG. 3 is an exploded perspective view of the lock device.

FIG. 4 is a side sectional view showing an assembled state of a holder member and a cover plate.

FIG. 5 is an enlarged side sectional view of the lock device according to the first embodiment.

FIG. 6 is an enlarged side sectional view showing an operation state of the lock device.

FIG. 7 is an enlarged side sectional view of a lock device according to a second embodiment.

FIG. 8 is a perspective view of an elevating body constituting the lock device of the above.

FIG. 9A is an enlarged sectional side view of the lock device according to the third embodiment, and FIG. 9B is an enlarged sectional side view showing an operation state thereof.

FIG. 10 is an enlarged side sectional view showing another configuration of the lock device according to the third embodiment.

FIG. 11 is an enlarged side sectional view of a lock device having a conventional configuration.

FIG. 12 is a bottom view of the manhole cover showing the lock device of the above.

[Explanation of symbols]

 A lock device 1 lid receiving frame 2 manhole cover 4 operation port 32 elevating body 33 shielding lid 35 convex surface 36 inclined edge 39 lock piece 40 locking surface 41 engaging end 42 inclined receiving edge 44 coil spring (biasing means) 48 notch

Claims (3)

[Claims] 1. A manhole cover attached to a lid receiving frame provided with an operation port on a peripheral edge, a shielding lid for shielding the operation port from below, and a lower rear surface inclined from a lower end to an upper rear end. An elevating body having an inclined edge and being held up and down at a position below the operation port of the manhole cover; an engaging end opposed from below to a locking surface formed on an inner surface of the lid receiving frame; And an inclined receiving edge which inclines in the same direction as the inclined edge of the supporting edge and supports the inclined edge. In a normal state, the engaging end is urged toward the lid receiving frame by the urging means so that the engaging end faces the locking surface from below. A lock member for holding a manhole cover, the lock device comprising: a lock piece that is held at a lock position and that moves back and forth in a front-rear direction to retreat to a retracted position through a pressing operation of an inclined edge by a pressing operation of a lifting / lowering body. . 2. A shielding lid having a plane shape substantially equal to a plane shape of an operation port, and a convex surface which is fitted into the operation port from below and which is substantially flush with an upper surface of the manhole cover is projected upward. The locking device for a manhole cover according to claim 1, wherein 3. A notch portion provided at a lower portion of a rear end of a lock piece so as to be able to tilt upward on an engagement end side in a state of being urged toward a lid receiving frame side. 2. The locking device for a manhole cover according to 2.