JP2535246Y2 - Ladder structure of lid for underground structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial application field> The present invention relates to a lid for an underground structure provided with a ladder at an opening of a mounting base, which can be in an upright state when used and can be in a laid down state when not in use. Ladder structure.

<Background Art> In a cover for an underground structure such as a manhole, there is provided a structure in which an undulating auxiliary ladder used when an operator enters and exits the underground structure is disclosed, for example, in Japanese Utility Model Publication No. 60-33162. There is a manhole with an auxiliary ladder described in.

In the manhole described in the above-mentioned publication, a pivoting piece for pivotally supporting the left and right side rods of the ladder is protrudingly provided on the inner peripheral surface of the receiving frame, and the base of the side rod is pivotally supported by a pin so that it can be raised and lowered on the pivoting piece. When the ladder is defeated, it protrudes from the inner periphery of the receiving frame of the receiving piece that supports the tip of the ladder,
A configuration is provided in which a fixing mechanism for directly fixing the side rod of the ladder in an up-and-down state and the pivotally attached piece on the receiving frame side is provided.

<Problem to be Solved by the Invention> However, the fixing mechanism for the manhole with the auxiliary ladder described above has a structure in which the lower part of the side rod of the ladder is inserted into a hole formed in the pivot piece to make the ladder undulate. Since a long hole through which a pin is inserted is formed at the base of the side rod, the ladder is apt to rattle in the left-right direction in the up-and-down state, and lacks stability when the worker moves up and down.

Also, in order to secure stability in the front-rear direction when the ladder is raised, it is necessary to match the dimensions of the side rod and the hole,
Further, in order to prevent the ladder from falling down in the closing direction, the insertion length of the lower portion of the side rod is also considerably required, and accordingly, the long hole also needs to be made a certain length.

As described above, by making the long hole longer, the above-mentioned play in the left-right direction is also remarkably generated, and the physical strength of the long hole portion of the side rod is reduced, so that the long hole may be deformed or damaged. .

Furthermore, since the side rod of the ladder is inserted into the hole, if the worker accidentally applies an upward force to the ladder during ascent or descent, the base end of the side rod is disengaged from the hole and the ladder falls down. Lack of reliability in safety measures against malfunctions.

An object of the present invention is to provide a lid for an underground structure which is extremely safe because the ladder in a standing state does not rattle and does not rise or fall even if an upward force is applied to the ladder by mistake when the worker goes up and down. To provide a ladder structure.

<Means for Solving the Problems> The present invention has been proposed to achieve the above object, and has a mounting base having an opening protruding in the center direction, and a receiving member disposed inside the opening of the mounting base. Left and right mounting portions, and a ladder having a parent girder and a plurality of steps and being pivotally attached to the mounting portion and capable of rotating between a falling state and an upright state, Between the parts, the supporting rod for rotation is above, the supporting rod for locking is erected below, and the base end of the ladder is pivotally connected so as to be coaxial with the supporting rod for rotation,
On the inside of the ladder, a fixing bracket having a long hole through which the rotation support rod and the step rail are inserted and a cutout portion that can be engaged with and disengaged from the locking support rod can be moved in the length direction of the main girder. , The notch of the fixing bracket is removed from the support rod for locking, and the leading end side is supported by the receiving member, so that the ladder can be brought to the down state, and the ladder is raised to lower the fixing bracket. The notch engages with the locking support rod, and the fixing bracket integrally connects the engagement support rod, the rotation support rod, and the step rail to hold the ladder in an upright state. I do.

According to the present invention, the mounting base having the opening is a receiving frame of a lid for an underground structure that supports the lid main body, or is a master lid having an opening that can be opened and closed by a child lid. I do.

<Operation> In the lid for an underground structure according to the present invention, when used, the ladder is erected as the base end or the center of the ladder, and a fixing bracket movably provided inside the ladder is engaged with the locking support rod. When not in use, the fixing bracket is detached from the support rod for engagement, and is laid down around the base end of the ladder when not in use. By supporting the distal end side, it is arranged horizontally inside the mounting base.

<Embodiment> Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The ladder structure 1 of the lid of the underground structure according to the embodiment includes a mounting base 2
And at least a ladder 3 located at the opening 2 ′ of the mounting base 2.

In the embodiment shown in the drawings, the mounting base 2 is a parent lid for a parent and child lid, and has an opening 2 ′ that can be opened and closed by a child lid (not shown) smaller in diameter than the parent lid. The opening 2 'is for an operator to enter and exit.

However, the mounting base 2 may be a receiving frame that supports the lid main body in a lid for an underground structure such as a general manhole.

On the inner wall of the opening of the mounting base 2, a pair of left and right arms 7a, 7a whose tips are connected by a contact piece 7, and reinforcing arms 7b, 7b having the same interval as the arms 7a, 7a are vertically arranged in two stages. At the front end, mounting portions 4 and 4 are vertically arranged, and between the mounting portions 4 and 4, a supporting rod 5 for rotation and a supporting rod 6 for locking are vertically provided. Have been.

The contact piece 7 is formed to be slightly wider than the width of the attachment portions 4 so that the parent girders 8, which will be described later, come into contact when the ladder 3 is erected.

The ladder 3 has a configuration in which a plurality of steps 9 are provided between the left and right main girders 8, and an auxiliary frame is provided outside each of the main girders 8.
10 is provided to increase the width and make it easier to grip when ascending and descending. The base ends of the left and right parent girders 8 are coaxial with the pivoting support rod 5 laid on the mounting part 4 and are rotatably pivoted to the outside of the mounting part 4. , 8 are provided with a fixture 12.

The fixing bracket 12 is a U-shaped frame which is long in the length direction of the main girder 8 and has long holes 13 formed in opposing pieces, and can be disengaged from the locking support rod 6 at the tip. Open end notch 14
Are formed. In the elongated holes 13, 13 of the fixing bracket 12, the above-described pivot support rod 5 and two step bars 9, 9 near the pivot support rod 5 are inserted. Therefore, the fixing bracket
The reference numeral 12 can move in the length direction of the parent girder 8 within the range of the length of the long hole 13.

When the ladder 3 is erected until the parent girder 8 comes into contact with the contact piece 7, the fixing bracket 12 descends by its own weight, and the notch 14 formed at the tip engages with the locking support rod 6. Therefore,
When the notch 14 of the fixing bracket 12 is locked to the locking support rod 6, the fixing bracket 12 integrally forms the locking support rod 6, the rotation support rod 5, and the two step bars 9, 9. Ladder 3 to connect to
And the ladder 3 can be prevented from tilting.

On the other hand, when the fixture 12 is raised in the range of the length of the elongated hole 13 in the upright state, the notch 14 is disengaged from the locking support rod 6 and the ladder 3 can be tilted to the falling state. here,
It is necessary to remove the fixing fitting 12 engaged with the locking support rod 6 only by manual operation, but since the fixing fitting 12 is not gripped when the worker moves up and down, the fixing fitting 12 is removed due to a malfunction of the worker. Can be prevented.

When the ladder 3 is in the down state, the auxiliary frame of the ladder 3 is attached to the receiving member 15 protruding from the mounting base 2 toward the inside of the opening 2 ′.
The ladder 3 is positioned substantially horizontally in the opening 2 'of the mounting base 2 so that the ladder 3 is kept in a lying state because the tip of the ladder 10 is locked.

Therefore, according to the present embodiment, in order to use the ladder 3 in the lying state inside the opening 2 ′ of the mounting base 2, the child lid is removed from the mounting base 2 to open the opening 2 ′, and the ladder 3 is opened. 3 is tilted upward with the pivoting support rod 5 as a fulcrum, and is raised until the parent girder 8 contacts the contact 7. In this case, the fixing bracket 12
It is necessary to keep the tip in the raised state so that the tip does not catch on the locking support rod 6.

When the main girder 8 of the ladder 3 comes into contact with the contact piece 7 and stands up, the fixing bracket 12 is lowered by its own weight or artificially to engage the notch 14 with the locking support rod 6 from above. . By this operation, the fixing bracket 12 integrally connects the rotation support rod 5, the locking support rod 6, and the two step bars 9, 9, so that the ladder 3 can be prevented from tilting.

Therefore, the fixture 12 engaged with the locking support rod 6
The ladder 3 tilts and does not fall unless the ladder 3 is artificially lifted and removed, so that it is possible to prevent the ladder 3 from falling down even if a worker who moves up and down the ladder 3 accidentally applies force to the ladder 3 upward. However, the ladder 3 does not rise because the lower portion is pivotally mounted.

As described above, when the ladder 3 is put into the use state, the ladder 3 is erected until the parent girder 8 contacts the contact piece 7, and then the notch 14 of the fixing bracket 12 is engaged with the locking support rod 6. Therefore, the engagement can be reliably performed.

When the use state of the ladder 3 has been completed, the fixing bracket 12 is detached from the locking support rod 6 to fall down, and the opening 2 'is closed with the child lid.

As mentioned above, although the lid for underground structures of the present invention was explained based on this example, the present invention is not limited to the above-mentioned example.

For example, in this embodiment, since the parent girder is pivotally attached to the outside of the attachment portion, both ends of the contact piece are projected from the attachment portion so that the parent girder contacts the contact piece. If it is pivoted inward, both ends of the contact piece do not need to project from the mounting portion.

In addition, when the ladder is in the upright state during use, the contact piece is not necessarily required if the operator reliably engages the notch of the fixing bracket with the locking support rod. In addition, the fixing bracket is movably supported by the two step rails and the rotation support rod, but may be supported by one, three, or more step rails and the rotation support rod. Good.

<Effects of the Invention> As described above, according to the present invention, inside the opening of the mounting base, the supporting rod for rotation is installed on the mounting part and the supporting rod for locking is installed below, and the base ends of the left and right parent girders are provided. A ladder pivotally attached to the mounting portion such that the portion is coaxial with the pivoting support rod, a plurality of steps are erected on the parent girder, and at least one or more pivoting support rods are provided inside the ladder. Since the fixing bracket is provided so as to be movably supported by the step rail and can be disengaged from the locking support rod,
The ladder can be brought into a standing state when in use and a standing state when not in use simply by moving the fixing bracket up and down. And
Since the fixing bracket supports the ladder in the standing state during use, even if an operator applies an upward force to the ladder that is gripped when going up and down by mistake, the fixing bracket does not come off from the locking support rod, so the ladder Can be prevented from tilting down. Also, since the base end of the parent girder is pivotally attached to the mounting portion, it is possible to prevent rattling.

[Brief description of the drawings]

1 is a schematic perspective view, FIG. 2 is a plan view partially showing a cross section, FIG. 3 is a solid line when the ladder is lying down, and a dashed line when it is upright. FIG. 4 is a partial longitudinal side view shown in FIG. 1 is a ladder structure of an underground structure lid, 2 is a mounting base, 3 is a ladder, 4 is a mounting portion, 5 is a supporting rod for rotation, 6 is a supporting rod for locking, 7 is a contact piece, 8 is a parent girder, 9 is a step, 12 is a fixing bracket.

Claims (3)

(57) [Scope of request for utility model registration] A mounting base having an opening protruding in the center direction of the receiving member, left and right mounting portions disposed inside the opening of the mounting base, a main girder and a plurality of step bars. A ladder that is pivotally mounted to the mounting portion so that the ladder can rotate between a lying state and an upright state, and between the left and right mounting portions, a turning support rod is located above, and a locking support rod is located below. The ladder is pivotally mounted so that the base end of the ladder is coaxial with the pivoting support rod. Inside the ladder, the long hole through which the pivotal support rod and the step rail are inserted is engaged with the latch. A fixing bracket having a notch that can be disengaged from the supporting rod is provided so as to be movable in the length direction of the main girder, the notch of the fixing bracket is removed from the supporting rod for locking, and the tip side is the receiving member. The ladder can be turned down by supporting the ladder. The notch is engaged with the support rod for locking, and the fixing bracket integrally connects the support rod for locking, the support rod for rotation, and the step rail to hold the ladder in an upright state. Lid ladder structure. 2. The ladder structure for an underground structure lid according to claim 1, wherein the mounting base having the opening is a receiving frame of the underground structure lid that supports the lid body. 3. A ladder structure for an underground structure lid according to claim 1, wherein the mounting base having the opening is a main lid having an opening that can be opened and closed by the child lid.