JP3942516B2 - Ladder for preventing fall of lid for underground structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fall-preventing ladder that is mounted in a receiving frame that fits and supports a lid main body of a lid for an underground structure to be used for falling-down and ascending and descending.
[0002]
In addition, the term “underground structure lid” as used in the specification of the present application means a large iron lid, a manhole lid, a sewage jar lid, an electric power / Openable and closable joint gutter lids, power transmission iron lids, power distribution iron lids, buried conduits under the road surface in waterworks and gas pipes, and their auxiliary equipment that protect underground facilities equipment and underground cables in communication A fire hydrant lid, a water control valve lid, a gate valve lid, an air valve lid, a gas piping lid, a water meter, etc., which function as an open / close door.
[0003]
[Prior art]
In the receiving frame of the lid for various underground structures installed on the ground surface such as roads, the fall prevention when the lid body is opened and the fall prevention for the worker to go up and down There are cases where a ladder is installed, but as such a fall prevention ladder, there is a fixing device that presses the upper edge of the receiving frame to the side lamps on both sides of the ladder that can be mounted on the receiving frame and can be raised and lowered. (For example, refer to Patent Document 1) Or can be carried and used in a plurality of receiving frames and the lid for an underground structure can be closed while being mounted on the receiving frames (for example, refer to Patent Document 2) ) Etc. are known.
[0004]
The pedestrians that make up these fall prevention ladders serve as a fall prevention to prevent people or vehicles passing in the vicinity from falling into the underground structure when lying down, and workers in the standing state It plays a role of hand grip when moving up and down.
[0005]
[Patent Document 1]
Utility Model Registration No. 2549064 (page 1-4)
[Patent Document 2]
JP 2001-32305 A (page 1-4)
[0006]
[Problems to be solved by the invention]
However, the conventional ladder for the fall prevention ladder is formed of a round bar shape or a plate-shaped member, and the plate-shaped member in the state in which the fall prevention ladder is laid down in the vertical direction. Therefore, it is difficult to stably receive a person who accidentally falls into the underground structure when lying down to prevent falling.
[0007]
Also, when the fall prevention ladder is raised and used for raising and lowering, there is no problem in strength, but it is difficult to grasp when the worker entering and exiting the underground structure grasps the step rail with his hand. It feels bad.
[0008]
The present invention has been made in view of the above points, and provides a ladder for an underground structure that can stably receive a person as a fall prevention unit and includes a step rail that can be easily grasped by hand as a lift unit. For the purpose.
[0009]
[Means for Solving the Problems]
The present invention relates to a fall prevention ladder that includes a plurality of step bars between a pair of supports arranged at intervals and is mounted in an upright manner in a receiving frame of a lid for an underground structure.
The踏桟is a portion that becomes the upper surface and the planar receiving in the inclined state,
On the side located above the side in an upright state of the receiving portion is provided a hand grip on the wall portion of the grip easy width,
The hand grip lower wall portion narrower than the hand grip upper wall portion is provided on the side of the receiving portion that is positioned on the lower side in a standing state .
[0010]
In such a configuration, it functions as a fall prevention in the lying down state, and in the unlikely event that a person tries to fall into the underground structure, it is a flat surface that forms the top surface of the ladder staircase It can be stably received by the receiving portion, and in the standing state, the hand grip upper wall portion is positioned above the receiving portion of the tram, so that it is easy to hold by hand for lifting and lowering.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
In fall prevention for ladders of the present invention, on the side which is located lower in the upright position of the receiving portion Ru Tei provided narrow hand grip lower wall portion than the hand grip on the wall. The standing angle when the fall prevention ladder is raised is considered to be an obtuse angle based on the lying down state in consideration of easiness of raising and lowering, that is, an angle at which the ladder is slightly inclined to the outside of the receiving frame. Is set to In this case, when the width of the hand grip upper wall portion and the width of the hand grip lower wall portion are approximately the same, the hand grip lower wall portion protrudes from the ascending / descending worker, making it difficult to grip. Therefore, if the width of the lower wall portion of the handgrip is made narrower than the width of the upper wall portion of the handgrip, the protrusion of the lower wall portion of the handgrip to the operator will be eliminated and it will be easier to grip, so that the worker can rest assured in the underground structure. It will be possible to go up and down.
[0012]
Moreover, the cross-sectional shape of the crosspiece can be a substantially U-shape with the lower part opened in the lying state. By adopting such a configuration, since the step rail has a hollow shape, it can be lighter than a bar having the same outer diameter as the step rail, and cost can be reduced.
[0013]
Furthermore, a non-slip protrusion can be provided on the surface of the upper hand grip wall. With this configuration, when the operator holds the step rail in an upright position, it is not only easy to grip because there is an upper wall part of the hand grip, but also the slip of the hand by the anti-slip protrusion on the upper hand grip part. Separation can be prevented.
[0014]
【Example】
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a plan view showing a state in which a fall prevention ladder according to an embodiment of the present invention is mounted on a receiving frame of a cover for an underground structure, and FIG. 2 is a state in which the fall prevention ladder shown in FIG. FIG. 3 is a cross-sectional view taken along line AA in FIG.
[0015]
As shown in FIG. 1, the fall prevention ladder 1 of the present embodiment is used by being mounted on a receiving frame 2 of a lid for an underground structure, and the fall prevention ladder 1 is interposed via two instrument connecting members 3. As shown in FIG. 2, the ladder main body 1 a is attached to a shelf 5 provided on the inner periphery of the receiving frame 2, and the ladder main body 1 a is rotated around a turning shaft 4 that connects the instrument connecting member 3 and the ladder main body 1 a. Or can be laid down as shown in FIG.
[0016]
The fall prevention ladder 1 includes a plurality of step bars 7 orthogonal to the support bars 6 between a pair of support bars 6 arranged at intervals, and becomes the upper surface of the step bars 7 in a lying state shown in FIG. In the event that a person should fall into the underground structure below the receiving frame 2 in the portion, a flat receiving portion 7a is provided so that it can be stably received, and in the standing state shown in FIG. The upper wall portion 7b of the handgrip is extended above the receiving portion 7a so that the operator can easily hold it when moving up and down in the underground structure, and the lower side of the receiving portion 7a in the standing state. A hand grip lower wall portion 7c narrower than the hand grip upper wall portion 7a is extended.
[0017]
As shown in FIG. 2 and FIG. 3, the standing angle when the fall prevention ladder 1 is erected is considered to be an obtuse angle based on the lying state, taking into account the ease of raising and lowering the operator, that is, The fall prevention ladder 1 is set to be slightly inclined to the outside of the receiving frame 2. In the case of the fall prevention ladder 1 of the present embodiment, the hand grip lower wall portion 7 c protrudes from the operator. The width 7cL of the hand grip lower wall portion 7c is made narrower than the width 7bL of the hand grip upper wall portion 7b so that the grip is easy to grip and does not hinder the lifting operation.
[0018]
In this case, the width 7bL of the upper hand grip wall portion 7b and the width 7cL of the lower hand grip wall portion 7c are not particularly limited, but in the fall prevention ladder 1 of this embodiment, the average hand of the operator When the width 7bL of the hand grip upper wall 7b is set to about 30 mm in consideration of the size of the hand grip, it becomes extremely easy to grip and the grip feeling is also good. Further, when the width 7cL of the hand grip lower wall portion 7c is set to about 18 mm, it becomes very easy to grip and the grip feeling is good, but the lower wall portion 7c has an auxiliary role, and the width 7cL is a work width. This role can be fulfilled with a minimum width enough to hook a person's thumb.
[0019]
Further, in the fall prevention ladder 1, the cross-sectional shape of the step rail 7 is substantially U-shaped with the lower part opened in the lying down state, so that the step rail 7 has a hollow shape. It was possible to reduce the weight as compared with a bar having an outer diameter, and to realize cost reduction.
[0020]
Further, two rows of anti-slip protrusions 8 are provided along the longitudinal direction of the step rail 7 on the surface of the receiving portion 7a of the step rail 7 and the surface of the hand grip upper wall portion 7a. Each of the anti-slip protrusions 8 is not continuous in the longitudinal direction of the crosspiece 7 but is arranged at an interval. The reason for this is that when the operator moves up and down in the underground structure, the worker may not always face the treadle 7 from the front, but may grip it from the side. This is to prevent slipping along the longitudinal direction of the step rail 7 when the person grasps the step rail 7 from other than the front.
[0021]
【The invention's effect】
The present invention has the following effects.
[0022]
(1) In a fall prevention ladder that includes a plurality of step bars between a pair of spaced supports and is mounted in an upright manner in a receiving frame of a cover for an underground structure, the step bars The upper part in the state is a flat receiving part, and the upper wall part with a width that is easy to grasp is provided on at least the upper side of the receiving part in the standing state to prevent falling in the lying state In the unlikely event that a person tries to fall, it can be stably received by the flat receiving portion that forms the top surface of the ladder's stepping rail. Since an upper wall portion of the hand grip is positioned on the upper side of the unit, it is easy to grip by hand for lifting and lowering, and the operator can move up and down into the underground structure with peace of mind.
[0023]
(2) In the fall prevention ladder according to the present invention, by providing the lower hand grip wall portion narrower than the upper hand grip wall portion on the lower side in the lying state of the receiving portion, Since the protrusion of the lower hand grip wall portion is eliminated and it becomes easier to grip, the worker can ascend and descend into the underground structure with peace of mind.
[0024]
(3) Since the cross-sectional shape of the step rail is substantially U-shaped with the lower part opened in the lying down state, the step rail becomes a hollow shape, so that it has a larger outer diameter than the bar. The weight can be reduced, and the cost can be reduced.
[0025]
(4) By providing a non-slip projection on the surface of the upper hand grip wall, slipping of the hand can be prevented.
[Brief description of the drawings]
FIG. 1 is a plan view showing a state in which a fall prevention ladder according to an embodiment of the present invention is mounted on a receiving frame.
FIG. 2 is a perspective view showing a state in which the fall prevention ladder shown in FIG. 1 is raised for raising and lowering.
3 is a cross-sectional view taken along line AA in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Fall prevention ladder 1a Ladder main body 2 Receptacle frame 3 Apparatus connection member 4 Rotating shaft 5 Shelf part 6 Supporting rod 7 Step rail 7a Receptacle part 7b Hand grip upper wall part 7bL Hand grip upper wall part width 7c Hand grip lower wall part 7cL Width 8 of the bottom wall of the hand grip Non-slip protrusion

Claims (3)

In the fall prevention ladder that includes a plurality of step bars between a pair of spaced supports and is mounted in an upright manner in the receiving frame of the lid for the underground structure,
The step rail is a flat receiving portion that is the upper surface in the lying state,
On the side located above the side in an upright state of the receiving portion is provided a hand grip on the wall portion of the grip easy width,
A ladder for preventing an undercarriage of a lid for an underground structure, wherein a lower hand grip wall portion narrower than the upper hand grip wall portion is provided on a lower side of the receiving portion in a standing state . The ladder for preventing a fall of the lid for an underground structure according to claim 1 , wherein a cross-sectional shape of the step rail is a substantially U-shape in which a lower portion is opened in a lying state. The ladder for preventing a fall of the lid for an underground structure according to claim 1 or 2 , wherein a non-slip protrusion is provided on a surface of the upper hand grip wall.

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