JP3107373B2 - Falling prevention ladders and underframes for underground structures with falling prevention ladders - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fall prevention ladder which is mounted on a support frame of an underground structure lid so as to be able to be raised and lowered, and a support frame of an underground structure cover provided with the fall prevention ladder. As used herein, the term “cover for underground structures” refers to large iron covers, manhole covers,
Sewage basin cover, openable and closable iron cover for power and communication underground facilities, underground cables, etc., iron cover for power transmission, iron cover for power distribution, buried conduit under water surface for water supply and gas piping and its accessories Fire hydrant cover, water control valve cover, partition valve cover, air valve cover, gas pipe cover, water meter cover, etc., which collectively function as an opening / closing door connecting equipment and the ground.

[0002]

2. Description of the Related Art Conventionally, as a ladder of a lid for an underground structure,
For example, a manhole with an auxiliary ladder described in Japanese Utility Model Publication No. 60-33162 is known.
The base of the ladder is pivotally supported on the pivoting piece provided on the inner peripheral surface of the receiving frame so that it can be raised and lowered, and the tip of the ladder is supported by the receiving piece formed on the inner circumference of the receiving frame. It can be used as a ladder by being used as a lid, and standing up and fixed.

[0003]

When the manhole is raised due to a temporary increase in the amount of rainfall, the lock provided on the lid body may come off the receiving frame and be opened. On the other hand, the above-mentioned auxiliary ladder is simply laid down and its tip is simply placed on the receiving piece on the inner peripheral surface of the receiving frame and supported, so if the lid body is opened, the auxiliary ladder is raised and lowered on the pivoting piece of the receiving frame. With the base of the ladder pivoted as much as possible as a fulcrum, the lid becomes upright at the same time as the lid is opened, and a pedestrian may fall into the manhole.

[0004] The present invention has been made in view of the above points, and even if the lid body is opened by the lifting pressure, the fall prevention ladder can maintain the falling state and the fall prevention ladder. An object of the present invention is to provide a receiving frame of a lid for an underground structure provided with a cover.

[0005]

SUMMARY OF THE INVENTION According to the present invention , a support is provided on an inner peripheral surface.
Roll that can be undulated to a receiving frame with multiple sections
A fall prevention ladder that can be attached to the support at the base end
Forming a functional mounting part, the tip side
Form a locking device supported by the support portion facing the support portion,
Below the locking member, there is an engaging member which is engaged with the lower surface of the supporting portion.
A stop member is provided, and the lock member is held at a lock position that engages with the lower surface of the support portion in the fall state , and can be displaced to the unlock position when standing up.

[0006] In the above configuration, the locking member formed on the tip side of the fall prevention ladder in the falling state is placed on the support portion, and the locking member is engaged with the lower surface of the support portion to lift the manhole into the manhole. Even in the event that pressure is generated and the lid body is opened, the fall prevention ladder can be kept in a lying state,
Falling into the manhole can be prevented.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a locking member
The support member is rotatably supported on a shaft provided below the locking member supported by the support portion, and the urging force of the elastic member in the fall state is provided.
Is held in the locked position by the
The ladder can be displaced to the unlocked position against the ladder, or can slide horizontally on the fall prevention ladder in the falling state.
Lock position and stand against the urging force when standing up.
It can be displaced to the lock release position .

With this configuration, when the fall prevention ladder is used as a ladder and then falls down, the locking member is automatically urged to the lock position, thereby preventing forgetting to lock. . Locking member, wherein in the inclined state
By the fastening member at the lock position to engage with the lower surface of the support part
It is held, and when standing up, release the fastening of the fastening member
The locking member is displaced to the unlock position .

With this configuration, the fall prevention ladder can be reliably held at the falling position, and it is possible to prevent a person other than the user from raising and lowering the fall prevention ladder. Further, the receiving frame of the lid for the underground structure is configured such that a fall prevention ladder having any one of the above-described locking members is mounted on a support formed on the inner peripheral surface of the receiving frame.

[0010] With such a structure, a lift is generated inside the manhole, and even if the lid body is opened, the fall prevention ladder does not stand up, so that a passer-by or the like falls into the manhole. Can be reliably prevented. In addition, the operator can easily descend into the underground structure by operating the locking member to release the engagement of the receiving frame with the lower surface of the support portion and to raise the fall prevention ladder.

(Embodiment 1) FIG. 1 is a plan view showing a fall prevention ladder according to the present invention (hereinafter simply referred to as "ladder") and a receiving frame of a lid for an underground structure provided with the ladder, and FIG. FIG. 3 is an exploded perspective view around the support portion, FIG. 3 is a plan view of a locking tool and a locking mechanism provided at the tip of the ladder of FIG. 1, and FIG. 4 is an exploded view showing the locking tool and the locking mechanism of FIG. It is a perspective view.

In FIG. 1, a cover 1 for an underground structure is provided with a receiving frame 2.
And a lid main body (not shown) mounted on the receiving frame 2, has a circular shape in plan view, and is installed so that the lid main body is flush with the ground surface. And the lid body,
When the lid is opened, the lid is lifted above the receiving frame 2 and is opened by horizontal turning or vertical inversion via a hinge mechanism. On the inner peripheral surface 2a of the receiving frame 2, a plurality of support portions 3 for mounting or supporting the ladder 4 are formed in the circumferential direction so as to protrude in a bow shape at six positions, for example, at equal intervals, and a protrusion is formed on the upper surface edge. 3a are formed. The ladder 4 is mounted on the receiving frame 2 by a mounting portion 10 provided on the base end side. As shown in FIG. 2, the mounting portion 10 includes a projection 3a on the upper surface edge of the mounting support portion 3.
An upper block 11 having an opening 11a into which the mounting portion 3 is fitted, and a lower block 12 disposed below the mounting support portion 3, and the mounting support portion 3 is sandwiched between the upper block 11 and the lower block 12. A bolt 13 is passed through the upper block 11 from the lower surface of the lower block 12 and screwed to the nut 14. By providing the projections 11b on the lower edge of the upper block 11, when the bolts 13 are tightened, the mounting block 3 is securely held between the upper block 11 and the lower block 12 with the projections 11b as fulcrums. ing. A mounting piece 11c is formed on the upper block 11, and the support shaft 15 is fixed to the mounting piece 11c, and the ladder 4 is pivotally mounted.

As shown in FIG. 1, the ladder 4 includes the mounting portion 10 described above, left and right side bars 5, 5, a plurality of horizontal bars 6 connecting these side bars 5, 5, and side bars 5, 5. , Which are fixed to the tip of the support member and supported on the support portions 3 for support.
And projecting portions 8, 8 projecting to the side of the left and right side rods 5, 5.
And the like. As shown in FIG. 2, a long hole 5a is formed in the base end of the side rod 5 along the longitudinal direction.
Is fixed to the mounting piece 11c by a nut 16 so that the end of the support shaft 15 is inserted through the elongated hole 5a.
The long hole 5a has a slightly smaller diameter on the distal end side than the diameter of the support shaft 15 and a slightly larger diameter on the base end side so that the support shaft 15 bites in the upright state of the ladder 4. In addition, support shaft 1
Reference numeral 5 also functions as a lateral rod on the base end side of the ladder 4.

As shown in FIG. 2, the upper block 11 is provided with a fixing portion 11d and an inclined surface 11e above the fixing portion 11d. The fixing portion 11d prevents the base end of the side rod 5 from abutting when the ladder 4 is raised and lowered, thereby preventing the ladder 4 from falling down. Further, an adjusting portion 17 in which an adjusting screw 17a is screwed is provided on the base end side of the side rod 5, and the amount of protrusion is adjusted so that the adjusting screw 17a comes into contact with the inclined surface 11e when the ladder 4 is raised. Thereby, the backlash of the ladder 4 in the front-back direction is prevented.

The locking member 18 is provided on one side 5 of the ladder 4.
And is rotatably supported by inserting a support shaft 15 into a hole 18a formed in the base end, and the tip is formed in a substantially U-shape. The portion 18b is configured to be engaged with and supported by the side rod 5 from above when the ladder 4 is folded down. On the upper end surface of the lock member 18 facing the adjustment portion 17, a slide portion 18c is formed substantially at the center, and a concave engagement portion 18d is formed between the slide portion 18c and the base end side.

When the ladder 4 is folded down, the slide portion 18c is located below the adjusting portion 17 of the side rod 5, and the lower end surface 18e on the distal end side of the lock member 18 contacts the upper surface of the horizontal rod 6 and the distal end. 18b engages with the side rod 5 (FIG. 8).
(A)). When the ladder 4 is raised and lowered in a state where the ladder 4 is slightly inclined to the outside of the receiving frame 2, the engaging portion 18d
7 is located at the engaging portion 18d. When the lock member 18 rotates outside the receiving frame 2 due to the weight of the weight portion 18b at the tip, the engaging portion 18d is engaged with the adjusting portion 17 to prevent the ladder 4 from rising and falling. (FIG. 8C).

Returning to FIG. 1, the locking members 7, 7 fixed to the tips of the left and right side rods 5, 5 of the ladder 4 have a hook 7b at the tip of the upper plate 7a. These hooks 7b are locked by the projections 3a in a state where the ladder 4 is folded down and the front part of the upper plate 7a of the locking tool 7 is placed and supported on the support 3 for support. Ladder 4 with tip side laterally offset
Is prevented from falling off when moved toward the proximal end.

A locking mechanism 25 is provided below the locking member 7 on one side as shown in FIGS.
The locking member 7 has a substantially U-shape in end view, and the above-described hook 7b is formed at the tip of the upper plate 7a. The side plate 7c is
It is fixed to the distal end of the side rod 5 by the bolt 21 and the nut 22, and is fixed to the horizontal rod 6 by the nut 23 together with the side rod 5 and the distal end 8 a of the overhang 8 of the ladder 4. A screw hole 7e is provided substantially at the center of the upper plate 7a.
A hole 7f is provided at a position facing the screw hole 7e of d.

As shown in FIG. 4, the locking mechanism 25 includes a lock plate 26 as a locking member, a torsion coil spring 27 as an elastic member, and a bolt 28 as a shaft. The lock plate 26 has a substantially rectangular shape in plan view, and has a lock portion 26a on one side and an operation portion 26b on the other side.
And a support piece 26 which is bent inward at a substantially right angle inward with respect to the lock portion 26a at the upper and lower ends at a substantially central position to form a substantially U-shape.
c and 26d are formed. The lock portion 26a has an upper end surface 26e that forms a horizontal plane and a lower end surface that is an inclined surface 26f that is inclined obliquely downward from the distal end toward the lower support piece 26d. The upper end surface 26e of the lock portion 26a is
The predetermined height h is set lower than the upper surface of the upper support piece 26c. The height h is set slightly larger than the thickness of the supporting portion 3 for supporting the receiving frame 2. Further, a small hole 26g is provided substantially at the center of the lock portion 26a.

The operating portion 26b has a distal end portion 26h which is
6c and 26d, they are bent at a substantially right angle on the same side, and a cutout 26i is provided at the upper end corner. This notch 26
“i” is for the operator to put a finger when rotating the lock plate 26. Upper and lower support pieces 26c, 26
The holes d can be fitted between the upper plate 7a and the bottom plate 7d of the locking member 7 and communicate with the screw holes 7e and the holes 7f.
k is drilled. The torsion coil spring 27 is configured such that a bolt 28 can be loosely fitted thereto, one end 27a is bent outward in the axial direction, and the other end 27b is bent laterally at substantially a right angle.

The lock plate 26 is provided on the upper plate 7 of the locking member 7.
a and the torsion coil spring 27
Is housed between the support pieces 26c and 26d and one end 27
a is locked by a locking portion 7g formed on the bottom plate 7d of the locking tool 7, and the other end 27b is inserted and locked into a small hole 26g of the lock plate 26. The bolt 28 has a hole 7f from below the bottom plate 7d of the locking member 7, a hole 26k of a support piece 26d of the lock plate 26, a torsion coil spring 27, and a lock plate 26.
Threaded through the hole 26j of the support piece 26c.
8a is screwed into the screw hole 7e of the upper plate 7a of the locking member 7.
Thus, the lock plate 26 and the torsion coil spring 27 are assembled to the locking member 7.

The lock plate 26 is rotatable in a horizontal plane with the bolt 28 as a rotation axis in a state where the lock plate 26 is assembled to the locking member 7, and counterclockwise by the spring force of the torsion coil spring 27 as shown in FIG. The ladder 4 is urged so that the end surface 26h 'of the distal end portion 26h of the operating portion 26b abuts on the side surface of the distal end portion 8a of the overhang portion 8 of the ladder 4 and is locked. In this state, in the lock plate 26, the lock portion 26a is located below the front part of the upper plate 7a of the locking member 7, and the upper end surface 26e is substantially spaced from the lower surface of the upper plate 7a as shown in FIG. Facing each other. This position of the lock plate 26 is a lock position where the lock plate 26 is engaged with the lower surface of the support portion 3 for support.
6b, torsion coil spring 27
By rotating clockwise against the spring force of the above, the lock position is operated to the unlock position.

Next, a method of using the ladder 4 will be described. The procedure for attaching the ladder 4 to the receiving frame 2 via the attaching portion 10 is as described above.
Here, the description is omitted. When the ladder 4 is used for preventing falling as shown in FIG. 1, a support shaft 15 is provided at the base end (large diameter side) of the long hole 5a formed at the base of the side rod 5 shown in FIG.
Is placed in the lying state, and the locking tool 7 fixed to the distal ends of the left and right side rods 5 is placed on the supporting portion 3 for supporting the receiving frame 2 so as to cover substantially the entire opening of the receiving frame 2. To At this time, as shown in FIG. 8A, the lock member 18 has the slide portion 18c positioned below the adjustment portion 17 and the lower surface 1 on the distal end side.
8e is in contact with the upper surface of the horizontal rod 6 of the ladder 4, and the tip 18b is engaged with the side rod 5.

On the other hand, as shown in FIGS.
In the locking mechanism 25 provided on the locking tool 7 on one side, the lock plate 26 is rotationally urged to the locked position by the spring force of the torsion coil spring 27, and as shown in FIGS. The tip of the lock portion 26a enters the lower side of the support portion 3 for supporting the receiving frame 2. At this time, the upper end surface 26e of the lock portion 26a of the lock plate 26 faces the lower surface of the support portion 3 with a slight gap d. In this state, when the tip side of the ladder 4 is pushed up by, for example, the lifting pressure in the manhole, the lock plate 26
Is locked to the lower surface of the supporting portion 3 for supporting the receiving frame 2 to prevent the ladder 4 from rising.

Therefore, a temporary increase in the amount of rainfall causes a lifting pressure in the manhole, so that a lock (both not shown) provided on the lid body attached to the receiving frame 2 comes off from the receiving frame 2. Even when the lid is opened, the ladder 4 can be kept in the lying state, and it is possible to prevent a pedestrian or the like from falling into the manhole. When the ladder 4 is used for raising and lowering, first, the operator inserts a finger below the locking tool 7 and operates the operating portion 26 b of the lock plate 26.
The fingertip is hooked on the notch 26i (FIGS. 4 and 5), and is rotated clockwise to an unlock position shown by a two-dot chain line in FIG. Remove from below the supporting part 3 for supporting. Thereby, the lock by the lock plate 26 is released. The operator raises the locking member 7 and raises the ladder 4 while holding the lock plate 26 in the unlocked state. The lock plate 26 returns to the locked position by the spring force of the torsion coil spring 27 when the operator releases his fingertip from the notch 26i.

When the ladder 4 is raised, the lock member 1
8 stands up together with the ladder 4 because the tip 18b side is in contact with the upper surface of the horizontal rod 6, and as shown in FIG. The long hole 5 of the side rod 5 along the fixing portion 11d of the upper block 11.
a, and adjust the adjusting screw 17a to the inclined surface 1
The ladder 4 is prevented from rattling by making it bite into 1e. When the adjusting portion 17 is positioned from the sliding portion 18c to the engaging portion 18d at the same time when the ladder 4 is lowered, as shown in FIG. 8C, the lock member 18 rotates to the outside of the receiving frame 2 due to the weight of the tip 18b. Therefore, the lock member 18 rotates, the engaging portion 18d engages with the adjusting portion 17, and the ladder 4 is locked at the upright position.

When the ladder 4 is to be laid down, the operator pushes the lock member 18 to release the state of engagement with the adjusting portion 17 and pulls the ladder 4 upward to gradually fall down. As shown in FIG. 6, the lock plate 26 includes a lock portion 26a.
The lower end surface is formed as an inclined surface 26f which is inclined obliquely from the front end toward the lower support piece 26d, and is provided on the edge of the support portion 3 for supporting the receiving frame 2 in the locked position as shown in FIGS. When the inclined surface 26 f of the lock portion 26 a hits the upper edge of the support portion 3 for supporting the receiving frame 2 due to the ladder 4 falling down, the torsion coil spring 27
3 is gradually rotated clockwise to the unlocked position shown by the two-dot chain line in FIG. 3 and locked just before the upper plate 7a of the locking member 7 comes into contact with the upper surface of the supporting portion 3 for support. Part 26a
Moves over the supporting portion 3 for support and the torsion coil spring 27
3 returns to the locked position shown by the dotted line in FIG. As a result, the lock plate 26 is engaged with the lower surface of the supporting portion 3 for supporting the receiving frame 2 to prevent the ladder 4 from rising.

(Embodiment 2) FIGS. 9 to 11 show a second embodiment of a locking mechanism provided below the locking member 7. FIG. The same members as those of the first embodiment shown in FIGS. 1 to 7 are denoted by the same reference numerals, and description thereof will be omitted. As shown in FIG. 9 and FIG.
It is composed of a lock plate 31 as a locking member and a spring 32 as an elastic member. A substantially central portion of the lock plate 31 is rotatably supported on a side plate 7c of the locking member 7 by a bolt 33 as a shaft so as to be rotatable in a vertical plane, and a distal end thereof is a lock portion 31a. Lock part 31
On the upper surface of a, an operation portion 31b for hanging a finger is formed so as to horizontally project outward. In addition, the lower surface of the lock portion 31a is an inclined surface 31c that is obliquely inclined from the distal end toward the lower surface of the central portion.

The spring 32 has one end locked to a pin 34 fixed to the base end side of the lock plate 31, and the other end locked to a pin 35 fixed to the side plate 7c of the locking member 7. The lock plate 31 is pulled and held at a lock position parallel to the upper plate 7a of the locking member 7. A stopper bolt 36 is screwed to the upper plate 7a of the locking member 7 so as to face the upper surface on the base end side of the lock plate 31, and the lock plate 31 is brought into contact with the lock plate 31 so that the lock plate 31 is brought into contact therewith. Rotation from the lock position counterclockwise is prevented. The lock plate 31 is in the state shown in FIG. 10 in which the ladder 4 is folded down and the upper plate 7a of the locking member 7 is placed and supported on the supporting portion 3 for supporting the receiving frame 2.
Is in a locked state in which the ladder 4 is engaged with the lower surface of the support portion 3 for supporting, and the ladder 4 is prevented from floating even if the ladder 4 is pushed up by a lift or the like in the manhole.

When the ladder 4 is to be erected, the operator inserts his / her finger below the operating portion 31b of the lock plate 31, and raises the lock plate 31 upward against the spring force of the spring 32 as shown by the arrow in FIG. Then, the lock portion 31a is released from below the support portion 3 for supporting the receiving frame 2 to release the lock. Note that the lock portion 31a of the lock plate 31 faces the lower surface of the support portion 3 for support with an interval capable of rotating from the lock position to the unlock position. The operator raises the ladder 4 in this state and locks the ladder 4 at the raised position as described above. When the operator releases his / her fingertip from the operation unit 31b, the lock plate 31 returns to the lock position by the spring force of the spring 32.

When the ladder 4 is to be laid down, the ladder 4 is pulled up and gradually laid down in the same manner as in the first embodiment. As shown in FIG.
Since the lower end surface of the lock portion 31a is formed as an inclined surface 31c which is inclined obliquely downward from the distal end toward the base end side, the inclined surface 31c of the lock portion 31a When it hits the upper edge of the support part 3 for support,
11 rotates in the direction shown by the arrow in FIG. 11 against the spring force of the spring 32, and the lock portion 31a is turned on just before the upper plate 7a of the locking member 7 comes into contact with the upper surface of the support portion 3 for support. After getting over the support portion 3, it returns to the lock position shown in FIG. 10 by the spring force of the spring 32. As a result, the lock plate 31 is engaged with the lower surface of the support portion 3 for supporting the receiving frame 2 to prevent the ladder 4 from floating.

(Embodiment 3) FIGS. 12 to 14 show a third embodiment of the locking mechanism.
The same members as those of the first embodiment shown in FIGS. 1 to 7 are denoted by the same reference numerals, and description thereof will be omitted. As shown in FIG. 12, locking members 7, 7 are fixed to the ends of the left and right side bars 5, 5, respectively, of the ladder 4, and the side bars 5,
A locking mechanism 40 slidable along these side rods 5, 5 is provided inside 5.

As shown in FIGS. 12 and 13, the locking mechanism 40 includes left and right lock plates 41 as locking members.
41 and a rod 4 as a connecting member for connecting them.
2 and a spring 43 as an elastic member. The lock plate 41 is a rod-shaped body that opens downward and has a substantially U-shape in end view.
Inclined surface 4 whose tip is inclined obliquely downward toward the base end side
1b and 41b. Long holes 41c, 41c are formed in the side plates 41a, 41a along the longitudinal direction near the front end, and holes 41d, 41d are formed in the rear end. On the other hand, the side rod 5 is provided with a hole 5b at a position corresponding to the long hole 41c of the lock plate 41 and a long hole 5d along the longitudinal direction at a position corresponding to the hole 41d. The long hole 5d has the same length as the long hole 41c of the lock plate 41.

As shown in FIG. 13, the lateral rod 6 on the tip side of the ladder 4 has an end 6a at both ends 41a of the lock plate 41,
The screw portion 6b is inserted through the long hole 41c of the side rod 41a, the screw portion 6c is inserted through the hole 5b of the side rod 5, and is fixed to the side rod 5 by the nut 44. The rod 42 is fixed to the holes 41d, 41d of the lock plate 41 by fitting the end 42a into the holes 41d, 41d of the lock plate 41, and the nut 45 so that the screw portion 42b at the tip can slide in the long hole 5d of the side rod 5. Fixed to Thus, the lock plate 41 is horizontally movable in the front-rear direction along the side rod 5 by the length of the long hole 41c as indicated by an arrow.

The spring 43 is housed in the lock plate 41, and one end 43a is locked to the end 6a of the horizontal rod 6, and the other end 43b is locked to the end 42a of the rod 42, so that the lock plate 41 is laddered. 4. Pull in the direction of the tip. As shown in FIG. 12, a support plate 46 is provided at the center of the ladder 4 along the longitudinal direction and bridged so as to be fixed to the upper surface of each horizontal rod 6. It extends to the top. The support plate 46 has a reinforcing member when the number of the horizontal rods 6 of the ladder 4 is reduced, and a function of narrowing the partition between the side rods 5 and 5 (to make the ladder 4 finer).

As shown in FIG. 14, in a state where the ladder 4 is folded down and the locking member 7 is placed and supported on the supporting portion 3 for supporting the receiving frame 2, the lock plate 41 is pulled by the spring 43 and the ladder 4 is pulled. 4, and the lock portion 41e enters below the support portion 3 and is in a locked state. When the ladder 4 is pushed up, the lock portion 41e of the lock plate 41 is locked to the lower surface of the support portion 3 of the receiving frame 2, and the ladder 4 is prevented from floating.

When the ladder 4 is to be erected, the operator grasps the rod 42 and as shown by the arrow in FIG.
The lock plate 41 is moved to the base end side of the side rod 5 against the spring force of 3, and the lock portion 41 e is removed from below the support portion 3 for supporting the receiving frame 2. Thereby, the lock is released.
The operator raises the ladder 4 in this state and locks the ladder 4 at the raised position as described above. When the operator releases his hand from the rod 42, the lock plate 41 returns to the locked position by the spring force of the spring 43.

When the ladder 4 is caused to fall down, the ladder 4 is pulled up by operating in the same manner as in the first embodiment, and is gradually fallen down. As shown in FIG.
Is that the lower end surface of the lock portion 41e is formed as an inclined surface 41b that is inclined obliquely downward from the distal end toward the base end side.
14 is pushed against the spring force of the spring 43 in the direction shown by the arrow in FIG. 14 so that the upper plate 7a of the locking member 7 is supported. Just before contacting the upper surface of the part 3, the lock part 41e gets over the support part 3 for support, and is returned to the lock position shown in FIG. As a result, the lock plate 41 is engaged with the lower surface of the support portion 3 for supporting the receiving frame 2 to prevent the ladder 4 from rising.

Fourth Embodiment FIGS. 15 to 17 show a fourth embodiment of the locking mechanism provided below the locking tool. The same members as those of the first embodiment shown in FIGS. 1 to 7 are denoted by the same reference numerals, and description thereof will be omitted. As shown in FIG. 15, a locking tool 7 is fixed to the tip of the side rod 5 of the ladder 4, and a locking mechanism 50 is provided below the locking tool 7. The locking mechanism 50 includes a lock plate 51 as a locking member, and a lock such as a padlock 52 as a fastening member for fastening the locking tool 7 and the lock plate 51.

The lock plate 51 has a lock portion 5 at the tip.
The rear end 51b is rotatably supported by the side plate 7c of the locking member 7 by a bolt 53 serving as a support shaft.
4 and the lock portion 51a is rotatable up and down. When the lock plate 51 is horizontally supported, the lock portion 51 a is located below the support portion 3 for supporting the receiving frame 2. An operation portion 51c for hanging a finger is provided on the lock portion 51a of the lock plate 51 so as to extend substantially horizontally outward, and a hole 51d is formed in a lower portion of the lock portion 51a. On the other hand, the lock plate 5 is
1 in parallel with the upper plate 7a of the locking member 7,
A hole 7i is formed at a position corresponding to d. And
In these holes 51d and 7i, a hook 52 of a padlock 52 is inserted.
a can be inserted.

As shown in FIG. 16, in a state where the ladder 4 is folded down and the locking member 7 is placed and supported on the supporting portion 3 for supporting the receiving frame 2, the lock plate 51 is rotated to the horizontal position, The hook 52a of the padlock 52 is inserted and locked in the hole 51d and the hole 7i of the locking member 7. When the lock plate 51 is held horizontally, the lock portion 5
1a penetrates beneath the supporting portion 3 for supporting, and can be engaged with the supporting portion 3. When ladder 4 is pushed up,
The lock portion 51a of the lock plate 51 is locked to the lower surface of the support portion 3 of the receiving frame 2 to prevent the ladder 4 from rising. Further, since the lock plate 51 and the locking member 7 are fastened by the padlock 52, it is possible to reliably prevent the ladder 4 from being raised and lowered by a person other than the worker.

When the operator lifts the ladder 4 by unlocking the padlock 52 with a key (not shown), and pulling out the hook 52a from the holes 7i and 51d of the locking member 7 and the lock plate 51, the operation shown in FIG. Lock plate 51 as shown
The lock 51a is pivoted downward by its own weight and disengaged from the support 3 for support. As a result, the ladder 4 can be raised and lowered.

When the ladder 4 is turned down, the worker
The operation portion 51c of the lock plate 51 is lifted with a fingertip and rotated upward to a substantially horizontal position as shown by the arrow in FIG. Next, the hook 52a of the padlock 52 is inserted into the hole 51d of the lock plate 51 and the hole 7i of the locking member 7 to lock. As a result, the lock plate 51 is engaged with the lower surface of the supporting portion 3 for supporting the receiving frame 2 to prevent the ladder 4 from floating.

Although the present invention has been described based on the four embodiments, the present invention is not limited to the embodiments.
For example, in the first and second embodiments, the locking mechanism is provided below the locking tool on one side. However, it may be provided on both sides. A fastening member such as a padlock may be added to the first to third embodiments in order to prevent the intrusion into an object.

Specifically, in the first embodiment, holes are formed in the lock plate 26 and the upper plate 7a of the locking member 7, and in the second embodiment, holes are formed in the lock plate 31 and the side rod 5. It is formed, and the hook of the padlock is inserted through these holes so that the lock plate 31 cannot be operated. In the third embodiment, a padlock hook is inserted into the long hole 41c of the lock plate 41 held at the lock position so that the lock plate 41 cannot be operated.

[0046]

According to the fall prevention ladder of the present invention, the fall prevention ladder is provided with a support formed on the inner peripheral surface of the receiving frame in a lying state.
A locking tool that is placed on the lifting unit, causing engage the lower surface of the support portion
By forming the locking member , the fall prevention ladder can be securely held in the lying state, and the lid body was opened due to the rise of pressure inside the manhole due to temporary increase in rainfall etc. Even in such a case, the fall prevention ladder is maintained in the lying state, so that it is possible to reliably prevent a pedestrian or the like from falling into the manhole.

Further, by automatically locking the locking member with the elastic member, it is possible to prevent the locking member from being forgotten to be hooked when the fall prevention ladder falls down. Further, by using the fastening member, the locking member can surely hold the fall prevention ladder in the lying state, and can surely prevent a person other than the worker from standing up.

In addition, since the receiving frame is provided with a fall prevention ladder having a locking mechanism, a lifting pressure is generated inside the manhole due to a temporary increase in rainfall or the like, and the lid body is opened by any chance. Even in this case, the fall prevention ladder does not stand,
In addition to being able to reliably prevent a pedestrian from falling into the manhole, operating the locking mechanism to release the engagement with the lower surface of the support portion of the receiving frame to raise the fall prevention ladder. Thereby, the worker can easily descend into the underground structure.

[Brief description of the drawings]

FIG. 1 is a plan view of a receiving frame of a lid for an underground structure provided with a fall prevention ladder according to the present invention.

FIG. 2 is an exploded perspective view of a support portion of a receiving frame of the fall prevention ladder of FIG. 1 and a base end portion of the fall prevention ladder.

FIG. 3 is a plan view of a locking tool and a locking mechanism provided at a tip of a fall prevention ladder of FIG. 1;

FIG. 4 is an exploded perspective view of the locking tool and the locking mechanism of FIG. 3;

5 is a plan view of the locking mechanism in a state where an upper plate of the locking tool of FIG. 3 is removed.

FIG. 6 is a side view of a state where the locking mechanism of FIG. 4 is assembled.

FIG. 7 is a sectional view taken along the line VII-VII of FIG. 3;

FIG. 8 is an explanatory view showing the falling and standing state of the fall prevention ladder shown in FIG. 1;

FIG. 9 is a partially cutaway plan view of a second embodiment of the locking mechanism provided on the fall prevention ladder.

FIG. 10 is a side view of the locking mechanism of FIG. 9;

FIG. 11 is an explanatory view showing an unlocking operation of the locking mechanism of FIG. 9;

FIG. 12 is a plan view of a receiving frame of a lid for an underground structure provided with a fall prevention ladder having a locking mechanism according to a third embodiment.

FIG. 13 is an exploded perspective view of the locking mechanism of FIG.

FIG. 14 is a sectional view taken along the line XIV-XIV in FIG. 12;

FIG. 15 is an exploded perspective view showing a fourth embodiment of the locking mechanism.

FIG. 16 is a view showing a locked state of the locking mechanism of FIG. 15;

17 is a diagram showing an unlocked bear of the locking mechanism of FIG. 16;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Underground structure lid 2 Receiving frame 3 Support part 4 Fall prevention ladder 5 Side rod 6 Side rod 7 Locking tool 8 Projection part 10 Mounting part 25, 30, 40, 50 Locking mechanism 26, 31, 41, 51 Lock plate (locking member) 27 Torsion coil spring (elastic member) 28, 33, 53 Bolt (shaft) 43 Spring (elastic member) 52 Padlock (fastening member)

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) E02D 29/12-29/14 E03F 5/02

Claims (5)

(57) [Claims] 1. A receiving frame having a plurality of supporting portions formed on an inner peripheral surface thereof.
A fall prevention ladder that is mounted so that it can
At the end side, a mounting portion that can be attached to the support portion is formed,
On the side, on the support part facing the support part in the lying state
Forming a locking device to be supported, below the locking device,
A locking member is provided for engaging the lower surface of the support portion.
The fall prevention ladder , wherein the material is held at a lock position for engaging with the lower surface of the support portion in a lying state , and can be displaced to an unlock position when standing up. 2. A locking member, pivotably journalled about an axis disposed below the fastener supported by the supporting portion, lodging shape
In the locked position by the biasing force of the elastic member.
When standing up, place it in the unlocked position against the biasing force.
The fall prevention ladder according to claim 1, wherein the ladder is displaceable . 3. The locking member is slidable horizontally with respect to the fall prevention ladder in the falling state, and is elastic in the falling state.
It is held in the locked position by the urging force of the member and stands up
The fall prevention ladder according to claim 1, wherein the ladder can be displaced to the unlock position against the urging force . 4. The support member according to claim 1 , wherein said support member is in a lying state.
Locked by the fastening member in the locked position that engages the lower surface of the part
When standing up, release the fastening of the fastening member and lock it
The fall prevention ladder according to claim 1, wherein the member is displaced to an unlock position . 5. A basement provided with a fall prevention ladder, wherein the fall prevention ladder according to any one of claims 1 to 4 is mounted on a support formed on an inner peripheral surface of a receiving frame. Receiving frame for structure lid.