JP2000087378A - Lock device of manhole cover - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lock device for locking a manhole cover to a manhole frame, provided with a pressure release function without incursion of rainwater or the like, preventing useless lock releasing, and facilitating maintenance and inspection with simple structure. SOLUTION: A stepped through-hole 6 vertically penetrating a manhole cover 4, an operation pin 8 having a large diameter head part 7 provided with a tool insertion part having direction on the upper end inserted in the stepped through-hole, a rubber ring 10 pinched between the stage part 6a of the stepped through-hole and the large diameter head part 7 of the operation pin in an elastic compression state, a lock piece 11 having a projection part or a notch part on an upward face relatively unrotatably fixed on the lower end of the operation pin and a notch part or a projection part provided for fitting the projection part or the notch part of the lock piece on the part of the circumference of the stepped through-hole of the lower face of the manhole cover are provided. The rubber elastic ring 10 prevents retraction of the lock piece 11, resistance is given to the rotation of the operation pin, sealing is performed between the operation pin and the stepped through-hole, and incursion of rainwater or the like is prevented.

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 locking a manhole cover to a manhole frame so that a cover plate of the manhole does not jump up or off or is opened by an outsider.

[0002]

2. Description of the Related Art A manhole is a vertical hole connected to a horizontal hole for sewerage and cable wiring provided in the ground, and a manhole cover is provided at the ground surface at the upper end of the vertical hole. The vertical hole is formed by a manhole block made of concrete, and a manhole frame usually made of cast iron is fixed to an upper end of the manhole block, and a manhole cover is fixed in a state fitted in the manhole frame. The manhole cover must be securely fastened so that it does not rattle or infiltrate rainwater from around the cover. So usually,
The manhole cover is attached by fitting the conical surfaces formed on the inner periphery of the upper end of the manhole frame and the outer periphery of the manhole cover.

Since the manhole cover is mounted in such a structure, the manhole cover does not usually rattle or come off. However, there is a danger that the manhole cover will jump or come off when the manhole is filled with gas and internal pressure is applied, and if an outsider can easily open the manhole cover, the manhole cover may be mischievously When opened, there is a danger that a person or an object may fall into the manhole, or a cable or the like disposed in an underground lateral hole may be damaged. Therefore, a lock device is provided on the manhole cover to prevent the manhole cover from being opened.

A lock device for a manhole cover does not need to have a complicated structure like a lock device for a door of a car or a safe, and is often left unmaintained outdoors for a long period of time. A simple structure is desirable. Usually, this lock device is configured such that a manhole cover is formed by projecting a claw or tongue piece provided on the back side of the manhole cover to the outer periphery and engaging with a flange or a downward step provided inside the manhole frame. The structure prevents the manhole from coming off. The structure in which the lock piece (claw or tongue piece) is advanced and retracted by rotating an operation pin provided on the manhole cover is often adopted. The lock piece is fixed to the lower end of the operation pin, and the operation pin is turned. When moving, the lock piece swings in an arc and moves forward and backward, or when the lock pin is connected to the operation pin via a link and the operation pin rotates, the lock pieces move forward and backward synchronously. Has been proposed.

[0005]

As described above, the locking device for the manhole cover can be of various structures, but rainwater or the like does not enter into the manhole, and the pressure in the manhole increases. It has a function to release the pressure sometimes to the atmosphere, has a structure in which the lock piece does not retreat due to vibration, etc., furthermore, outsiders can not easily release the lock, and people trapped in the manhole Since it is required that the lock can be released from the lower surface, that the structure be simple, and that maintenance and inspection are not required, the various lock structures provided so far have not always been satisfactory.

[0006]

According to the present invention, a lock piece 1 attached to the lower surface of a manhole cover having a conical outer peripheral surface that fits into a conical surface formed inside the upper end of the manhole frame 1 is provided.
1 is a lock device which protrudes below an inner flange or a downward step portion 3 formed on an inner periphery of an upper end portion of the manhole frame to prevent the manhole cover from being opened, wherein an upper end portion vertically penetrating the manhole cover 4 has a large diameter. A stepped through-hole 6, an operation pin 8 having a large-diameter head 7 provided with a directional tool insertion portion 15 at an upper end inserted into the stepped through-hole, and a step 6a of the stepped through-hole; A rubber ring 10 is held between the large-diameter head 7 of the operation pin in an elastically compressed state, and a protrusion or notch is provided on an upwardly-facing surface fixed to the lower end of the operation pin so as not to rotate relatively. A lock for a manhole cover, comprising: a lock piece (11); and a notch or protrusion provided at a portion around the stepped through hole on the lower surface of the manhole cover so as to fit with the protrusion or notch of the lock piece. The above-mentioned problems can be solved by providing a device. Solution to that.

As a more preferable structure of the lock device having the above structure, a tool insertion portion 15 provided at the upper end of the large-diameter head 7 of the operation pin has an arrow shape, and a lock fixed to the direction of the arrow and the lower end of the operation pin. A structure in which the extending direction of the piece 11 is matched, and a tool insertion portion 15 is formed as a recess, and an opening 19 is provided in the manhole cover 4 for communicating the upper end large diameter portion 6b of the stepped through hole and the lower surface of the cover. In addition, a structure is proposed in which the operation pin 8 is provided with a groove 20 for communicating the tool insertion recess 15 with the periphery of the large-diameter head 7.

[0008]

The worker who opens and closes the manhole cover mounted by mutual fitting of the conical surfaces usually uses a crowbar to open the tightly fitted manhole cover using the boosting force of the leverage action. Is going. In the structure of the present invention,
If a protrusion with a cross-sectional shape that matches the cross-sectional shape of the tool insertion recess formed on the upper surface of the large-diameter head of the operation pin is welded to the end of the burl, the protrusion can be used to increase the size of the manhole cover operation pin. Insert into the diameter head and push down from above to remove the rubber ring 10
Further, the operating pin 8 is slightly moved downward by elastically compressing, and the engagement between the protrusion or the notch of the lock piece and the notch or the protrusion around the stepped through hole is released. By rotating, the lock piece advances or retracts to lock and release the lock piece.

If the tool insertion portion (recess 15 or projection) has a special sectional shape, rubber ring 10 can be used.
Since it is an operation to rotate the operating pin while compressing it and applying its frictional force, it is very difficult to rotate the operating pin with a general tool, so it is difficult for an outsider to open the manhole cover without permission. Can be prevented.

The rubber elastic ring 10 maintains the fitting between the protrusion or notch of the lock piece and the notch or protrusion around the stepped through-hole due to the elasticity to be restored, and generates vibrations or the like. Prevents the lock piece 11 from retreating naturally, gives a certain resistance to the rotation of the operation pin as described above, and further seals the space between the operation pin and the stepped through hole so that rainwater or the like enters the manhole. It has three types of action to prevent inflow.

The lock piece 11 is fixed at the advanced position by fitting the protrusion or notch into the notch or protrusion around the stepped through hole 6.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the embodiments shown in FIGS. FIG.
The manhole frame includes an outer frame fixed to a manhole block, and an inner frame 1 fitted up and down and tiltably in the outer frame. Face 2
Is formed, and the downward stepped surface 3 is formed immediately below.

The manhole cover 4 is made of cast iron, and has a conical outer peripheral surface 5 fitted to the conical inner peripheral surface 2. Stepped through holes 2 penetrating in the vertical direction are provided at two positions (only one position is shown in the figure) at positions close to the outer periphery of the manhole cover 4. The stepped through hole 2 is a large diameter circular hole 6b at the upper end,
An upward step surface 6a is formed at a portion where the diameter changes. A portion of the lower surface of the manhole cover 4 around the stepped through hole 6 slightly protrudes downward.

An operation pin 8 having a large diameter head 7 at the upper end is inserted into the stepped through hole 6. At the tip of the operation pin 8, an oval short protrusion 13 having a width between two surfaces smaller than a diameter is provided.
And a screw hole 9 is provided at the tip axis. This operating pin is fitted with a ring 10 made of synthetic rubber such as urethane rubber under the neck of the large diameter head 7 and inserted into the stepped through hole 6, and a lock piece 11 is fixed to the tip with a screw 18. Is attached. The lock piece 11 has a shallow notch groove 12 in the center of its upper surface.
The groove is fitted with the short oval projection 13 at the tip of the operation pin 8 to prevent the lock piece from rotating relative to the operation pin.

On the other hand, in the portion around the stepped through hole 6 on the lower surface of the manhole cover 4, as shown in FIG. 3, radial cutout grooves 14 are provided on both sides so as to sandwich the stepped through hole. . When the lock piece 11 faces outward in the radial direction, bank-shaped projections 16 on both sides in the width direction of the upper surface of the lock piece.
However, the lock piece 11 is fitted in the notch groove 14 to keep the lock piece 11 in the outward state, that is, in the advanced state.

The rubber ring 10 interposed between the step surface 6a of the stepped through hole 6 and the large diameter head 7 of the operation pin is slightly crushed, and In addition to preventing rainwater from entering the hole, the operation pin 8 is urged upward so that the lock piece 11 and the notch groove 14 do not come off from each other. The retracted position of the lock piece 11 is a position rotated by about 90 degrees from the advanced position, and the stopper 17 for preventing the lock piece 11 from being excessively rotated from this position is provided by the protrusion 16 of the lock piece 11.
Projecting from the lower surface of the stepped through-hole so as to abut the same.

FIG. 1 is a partial cross-sectional view showing a state in which the lock piece has advanced, in which the upper end of the lock piece that has advanced and the downward step surface 3 that engages with the lock piece provided on the manhole frame are shown. There are some gaps between them. When the gas is filled in the manhole or the like, the manhole cover is lifted up by the gap due to the internal pressure, a gap is opened in the conical fitting surface, and the pressure in the manhole is released.

An upper surface of the large-diameter head 7 of the operation pin is formed with an arrow-shaped recess 15 as shown in FIG. 2, and a projection having a sectional shape just inserted into the recess is used to open and close the manhole. Weld to the end of the crowbar to be used. The protrusion attached to the crowbar from the closed state in FIG.
To the rubber ring 10
Is compressed, the operation pin 8 moves down, and the ridge 16
And the notch 14 around the stepped through hole is disengaged. Then, if the pivot is made while pressing the crowbar, the lock piece 11
Pivots around the operation pin 8 and retreats from the downward step surface 3 of the manhole frame as shown by the two-dot chain line in FIG. 2, so that the burl is not shown in the same manner as when the normal manhole cover is opened. Hook on the hook of the manhole frame and open the manhole cover using leverage.

When closing the manhole cover, the manhole cover is fitted to the manhole frame, and then the protrusion of the burl is inserted into the arrow-shaped recess, and the operation pin is rotated. When the lock piece advances and enters under the downward step portion 3 of the manhole frame, the ridge 16 of the lock piece and the cutout groove 14 around the stepped hole are fitted, and the elasticity of the rubber ring 10 The advanced state is maintained. At this time, the arrow-shaped concave portion 15 has the arrow pointing outward in the radial direction, and it can be confirmed from the outside that the lock piece is in the advanced state.

FIG. 4 is a cross-sectional view of a lock device for sewerage which does not require airtightness. The tool insertion recess at the upper end of the operation pin 8 and the sediment deposited around the recess are filled with the upper end of the stepped through hole 6 of the lid 4. In this embodiment, rainwater flows into the manhole together with the rainwater from the opening 19 connected to the diameter portion 6b. This is an embodiment in which the time and effort for removing earth and sand when the lid is opened is omitted. When the tool insertion portion is a concave portion, a guide groove 20 for allowing earth and sand and water to flow out from the concave portion to the periphery of the large diameter head 7 is provided in the operation pin as shown in FIG.

[Brief description of the drawings]

FIG. 1 is a sectional front view of a lock device in a state where a lock piece of the present invention has advanced.

FIG. 2 is a plan view of FIG. 1;

FIG. 3 is a sectional side view of FIG. 1;

FIG. 4 is a cross-sectional front view of a lock device that allows water and earth and sand to flow into a manhole.

[Explanation of symbols]

 1 Manhole frame 3 Stepped section 4 Manhole cover 6 Stepped through hole 6a Stepped stepped hole 7 Large diameter head 8 Operation pin 10 Ring 11 Lock piece 15 Tool insertion part

Claims (3)

[Claims] 1. A lock piece (11) attached to the lower surface of a manhole cover provided with a conical outer peripheral surface which fits into a conical surface formed inside the upper end of the manhole frame (1) is provided on the inner periphery of the upper end of the manhole frame. In a lock device that advances below the formed inner flange or the downward step (3) to prevent the manhole cover from being opened, the upper end vertically penetrating the manhole cover (4) has a large diameter stepped through hole (6). ) And a large-diameter head provided with a directional tool insertion portion (15) at the upper end inserted into the stepped through hole.
An operation pin (8) having a (7), a rubber ring (elastically compressed between a step (6a) of a stepped through hole and a large-diameter head (7) of the operation pin ( 10), a lock piece (11) having a protrusion or notch on the upward surface fixed to the lower end of the operation pin so as to be relatively non-rotatable, and the lock around the stepped through hole on the lower surface of the manhole cover. A locking device for a manhole cover, comprising: a notch or projection provided to be fitted with a projection or notch of a piece. 2. A large-diameter head (7) of an operation pin is provided with an arrow-shaped tool insertion portion (15) at an upper end thereof, and a direction of the arrow and an extension of a lock piece (11) fixed to a lower end of the operation pin. The locking device for a manhole cover according to claim 1, wherein the direction is made coincident with the direction. The tool insertion portion (15) is a tool insertion recess, and the manhole cover (4) has an opening (19) for communicating the large-diameter portion (6b) at the upper end of the stepped through hole with the lower surface of the cover. The operating pin (8) is provided with a groove (20) for communicating between the tool insertion recess (15) and the periphery of the large diameter head (7). Or the locking device for a manhole cover according to 2 above.