JP2597227Y2 - Manhole iron lid locking device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a manhole iron cover provided at an inspection port of an underground structure facility, particularly, by rotating a manhole iron cover attached to a receiving frame in a circumferential direction.
The present invention relates to a manhole iron cover locking device provided so that the manhole iron cover can be locked to a receiving frame.

[0002]

2. Description of the Related Art Conventionally, as this type of locking device, for example, there is one disclosed in Japanese Utility Model Laid-Open Publication No. 2-42754. As shown in FIG. 5, a plurality of locking steps c are formed at equal intervals on the inner peripheral surface b of the receiving frame a, while the locking steps c are formed on the back surface of the manhole iron cover d. A plurality of engaging projections e... That can be engaged with the lower surface are formed, and the manhole iron cover d is rotated in a circumferential direction in a state where the engaging projections e. It is configured to engage with the lower surface of the locking step edge c from the side, and to obtain a locked state at the time of closing the lid by an upward retaining action.

[0003]

However, in the above-mentioned conventional locking device, the locking projections e formed on the manhole iron cover d project from the back surface of the manhole iron cover d. Therefore, if the manhole iron cover d is accidentally dropped or hit against something during transportation or opening / closing work of the manhole iron cover d, the locking projections e... Since the locking projections e do not have enough strength to withstand such an impact, they have a disadvantage that they are easily broken.

An object of the present invention is to provide a manhole iron cover locking device which does not have the above-mentioned disadvantages.

[0005]

SUMMARY OF THE INVENTION According to the present invention, a plurality of locking step edges are formed on the inner peripheral wall of a receiving frame on which a manhole iron cover is to be attached, while the manhole iron cover is opposed to the locking step edge. A manhole iron cover formed on a support portion extending downward from several places on the back surface so as to be engaged with and beneath the locking step edge by a circumferential rotation operation of the manhole iron cover. In the locking device of (1), a protective wall portion which is located outside the locking protrusion formed on the manhole iron cover and protrudes downward from the locking protrusion is formed all around or partially on the manhole iron cover. It is characterized by the following.

[0006]

When the manhole iron cover is dropped or hit, the locking projection is protected by the protection wall from the impact, so that the locking projection can be prevented from being damaged.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. In the drawings, 1 indicates a manhole iron cover, and 2 indicates a receiving frame on which the manhole iron cover 1 is attached. The receiving frame 2
Is composed of inner and outer double annular portions 2a and 2b connected at the lower portion, and the inner circumferential wall 7 of the inner annular portion 2a has 180
° A pair of locking step edges 3, 3 are formed at different positions. As shown in FIG.
A downwardly inclined guide surface 3a and a horizontal locking surface 3b are formed on the lower surfaces of the locking step edges 3 in this order from the front.
And a vertical stopper surface 3c are provided continuously.

On the other hand, on the back surface of the manhole iron cover 1, a pair of support portions 4, 4 is provided to extend downward from slightly inside of the peripheral portion so as to face the locking step edges 3, 3. , 4 are formed with locking projections 5, 5 which can be engaged with the locking surfaces 3b, 3b of the locking step edges 3, 3, respectively.

On the peripheral edge of the manhole iron cover 1, protective walls 6, 6 extend downward at positions outside the locking projections 5, 5. The protective walls 6, 6 are formed such that their lower ends project below the locking projections 5, 5. Further, the protective wall portions 6 and 6 need only be provided at least at portions that cover the locking projections 5 and 5, but may be provided over the entire circumference of the manhole iron cover 1.

In this configuration, in order to lock the manhole iron cover 1 on the receiving frame 2, the manhole iron cover 1 is
By rotating the manhole cover 1 in a predetermined direction using a special handle (not shown) in a state where the cover is attached to the
The locking projections 5, 5 of the manhole iron cover 1 enter the lower surfaces of the locking surfaces 3b, 3b from the guide surfaces 3a, 3a of the locking step edges 3, 3 of the receiving frame 2, and further contact the stopper surfaces 3c, 3c. The rotation of the manhole cover 1 is stopped. As a result, the locking projections 5, 5 are prevented from falling upward by the locking surfaces 3b, 3b, and a state where the manhole iron cover 1 is locked is obtained.
On the other hand, to release this locked state, the manhole iron cover 1
May be rotated in a direction opposite to the above.

When the manhole iron cover 1 is accidentally dropped or hit against something during transportation or opening / closing work of the manhole iron cover 1, the protection walls 6, 6 are locked by the locking projections 5, 5. By being provided so as to protrude further downward, the locking projections 5, 5 can be protected against impact from below by the protective wall portions 6, 6. Further, since the protective wall portions 6, 6 are provided at positions outside the locking projections 5, 5, the locking projections 5, 5 can be protected against an impact from the outside.

In the above embodiment, the two locking step edges 3 and 3 and the locking projections 5 and 5 are arranged at positions different from each other by 180 ° on the circumference. The number of 3, 3 and the locking projections 5, 5 is not limited to this, and three or more may be provided at equal intervals.

In the above embodiment, the locking step edge 3 of the receiving frame 2 is formed in an inverted L-shape, and the locking projection 5 of the support portion 4 is formed in a protruding rod shape. It is also possible to form the locking step edge 3 in a protruding rod shape and form the locking projection 5 in an inverted L-shape.

[0014]

According to the present invention, as described above, a protective wall portion is provided at a position outside the locking protrusion provided on the manhole iron cover so as to protrude downward from the locking protrusion, so that the manhole iron cover is dropped. In the case of hitting or hitting, there is an excellent effect that the locking projection is protected from the impact and damage can be prevented.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a locking device for a manhole iron cover according to the present invention.

FIG. 2 is an enlarged side sectional view taken along line AA in FIG.

FIG. 3 is an enlarged cross-sectional view of a locking projection and a protective wall portion of a manhole iron cover.

FIG. 4 is an enlarged bottom view of the above.

FIG. 5 is a longitudinal sectional view of a conventional structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Manhole iron cover 2 Receiving frame 3 Locking step edge 4 Support part 5 Locking projection 6 Protective wall part 7 Inner peripheral wall

Claims (1)

(57) [Scope of request for utility model registration] 1. A plurality of locking step edges are formed on an inner peripheral wall of a receiving frame on which a manhole iron cover is attached, and extend downward from several places on the back surface of the manhole iron cover so as to face the locking step edges. A locking device for a manhole iron cover, wherein a locking projection is formed on the supporting portion so as to be engageable below the locking step edge by a rotating operation of the manhole iron cover in a circumferential direction. A manhole iron cover, wherein a protective wall portion which is located outside the locking protrusion formed on the lid and protrudes downward from the locking protrusion is formed all around or partially on the manhole iron cover. Locking device.