JP2002004315A - Fall preventing device for manhole combined with ladder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a safe and sure attaching structure for grid-like inner lid which can prevent the falling of persons and utensils into a manhole when the lid plate, of the manhole comes off and also functions as a ladder used when persons get in and out of the manhole for a fall preventing device installed to the manhole. SOLUTION: The fall preventing device is provided with the grid-like inner lid which can be erected and tilted along a horizontal supporting shaft and is equipped with horizontal sash bars arranged in parallel with the supporting shaft, a holding bracket equipped with a lateral groove which is relatively moved in the axial direction of the supporting shaft and is engaged with the inner lid when the lid is in a standing state, an urging means which laterally urges the inner lid and holding bracket in the direction in which the lid and bracket are engaged with each other, and a locking member which inhibits the movement of the groove and inner lid in the direction in which the engaged groove and lid are disengaged from each other. It is possible to provide a second lateral groove which is engaged with the inner lid when the lid is tilted on the holding bracket. It is also possible to provide a fine grid plate or net on the upper surface of the inner line when the lid is in a tilted state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fall prevention device provided on a manhole frame, which prevents objects from falling into the manhole when a cover plate closing the manhole comes off, and a manhole. The present invention relates to the above device having a lattice-shaped inner lid which also has a function as a ladder when entering and exiting the inside.

[0002]

2. Description of the Related Art A manhole is provided as a passage for maintenance and inspection to an underground sewer, a wiring facility, and the like. The manhole is usually opened on the ground surface such as a road, and the opening is closed with a hole (hole). A cover plate made of cast iron is provided. Underground facilities are inspected and repaired by opening this heavy cast-iron cover plate, and workers enter the manhole. Usually, the cover plate is left open during work. Therefore, if a large tool or the like is accidentally dropped into the manhole during this operation, there is a risk of damaging underground facilities and workers. In addition, if the underground space connected to the manhole is installed on a slope, the water that has flowed into the underground space at a high place during floods etc. The internal pressure may act to cause the lid plate to fly off. When the manhole cover is opened due to such a phenomenon, there is a danger that people fall into the manhole,
The danger is particularly great during floods when the manholes are submerged.

[0003] In order to prevent such danger,
Install a wire mesh in the manhole to prevent falling objects,
It has been proposed to prevent the falling of objects and falling of a person into a manhole by setting the ladder of an upside down type in a state of being laid down. A ladder or handrail is provided in the manhole for entry and exit of the person, but the above-mentioned up-and-down ladder forms an upper end portion of a ladder that protrudes to the surface of the ground when raised. By making the width wider than required for the ladder, it becomes a rough lattice-shaped inner lid that closes the opening of the manhole when it lays down.

[0004] In this type of ladder which also serves as a lattice-shaped inner lid of the manhole, when a large internal pressure is applied to the manhole in the lying state, the inner lid rises at the same time as the lid plate jumps, In order to prevent the function as a protective lid from being unable to be exhibited, a structure with a lock mechanism that locks the inner lid in the down state, or when standing up and using it as a ladder, to prevent its falling down, A structure has been proposed in which a standing ladder is dropped into a guide bracket to prevent the ladder from falling down (for example, see Japanese Patent Application Laid-Open No. 11-107303).

[0005]

However, in the structure proposed in the prior art, a separate lock mechanism is required for holding the upright state and the holding state in the down state, and the number of parts increases and the cost increases. There is a problem, and in a structure where the ladder is dropped into the guide and held upright, the entire ladder must be lifted when unlocking, so when installing a sturdy ladder in a large manhole, the ladder must be The ladder becomes heavy and requires arm strength at the time of unlocking. In addition, there is a problem that if the ladder is to be loosened, the dropping stroke must be increased.

According to the present invention, in a manhole provided with an upside down type inner lid which can be used as a ladder when standing up, the manhole can be easily laid down and upright, and the upright state can be maintained safely and securely. An object of the present invention is to provide a mounting structure for an inner cover of a manhole, which does not require a large arm strength for release and can maintain a standing state and a falling state with a simple structure.

[0007]

According to the present invention, there is provided a fall prevention device for a ladder for a manhole, comprising a horizontal bar 12 which is capable of standing up and down around a horizontal support shaft 7 and which is parallel to the support shaft. , A holding bracket 8 having a lateral groove 9 which moves relative to the support shaft in the axial direction and engages with the standing inner lid, and a direction in which the inner lid 11 and the holding bracket 8 are engaged. And a lock member 18 for preventing the lateral groove 9 and the inner lid 11 engaged with each other from moving in the detaching direction.

[0008] The holding bracket 8 is attached to the inner lid 1 in a lying state.
1 can be provided with a second transverse groove 10 which engages with
In the structure in which the lateral groove 9 and the second lateral groove 10 are integrally provided in the holding bracket 8, the standing state of the inner lid and the standing state of the inner lid can be held by the urging force of one urging member. The support shaft 7 for pivotally supporting the inner lid 11 with the holding bracket 8 is provided.
According to the structure in which the direction of the lateral grooves 9 and 10 is provided in the both end portions in the same direction, the holding and release of the inner lid on both the left and right sides can be performed in one operation.

Incidentally, the lateral grooves 9, 10 of the holding bracket are provided.
Is a flange 21 on the back side of the horizontal groove 9 for holding the upright state and a flange 2 below the second horizontal groove 10 for holding the lying state.
2 is made larger than the axial movement stroke of the inner lid 11 at the time of disengagement, so that the inner lid 11 has an action as a stopper for preventing the inner lid 11 from rotating outside its standing position and below its falling position. be able to.

As the lock mechanism 18 for fixing the axial movement of the support shaft of the inner lid 11 in the upright state, a gravity pendulum type, a spring rotation type, a spring advance / retreat type, a ratchet claw type, or the like shown in the illustrated embodiment is used. Various structures can be employed.

Further, by providing a fine lattice plate or net on the upper surface of the inner lid 11 in the lying state, it is possible to prevent small objects from falling into the manhole without impairing the function as a ladder when standing up. It can have an effect.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to an embodiment shown in FIGS. The manhole frame shown in the embodiment of the figure includes an outer frame 1 and an inner frame 2 that can be moved up and down in the outer frame and that can fix the ascending and descending position, and moves up and down the inner frame 2 according to the height of the road surface. This structure (including tilting) allows the height of the manhole to be adjusted according to the height of the ground surface, but illustration and description of the structure for raising and lowering and fixing the inner frame 2 are omitted.

The upper surface of the inner periphery of the inner frame 2 is a tapered hole, and the cover plate 3 made of cast iron is fitted into the tapered hole by wedge action. On the lower surface of the outer frame 1, a square section member 33 is formed in a bar shape near the inner periphery of the inner frame 2 in plan view. The figure shows a state in which the cover plate 3 is opened, and the opened cover plate 3 is loosely connected to the inner frame 2 by a connection lever 4 suspended on the lower surface at one circumferential position. The upper end of the connecting lever 4 and the cover plate 3 are pivotally connected by a horizontal pin 5 so as to be relatively swingable. Two support brackets 6 are integrally attached to the square section member 33 with bolts 34 at both sides of a portion holding the connecting lever 4 so as to be freely movable. Thus, both end portions of the support shaft 7 are supported so as not to move in the axial direction. One of the two support brackets (the upper one in FIG. 1) supports the end of the support shaft 7, and the opposite end 7a of the support shaft 7 penetrates the support bracket on the opposite side. It is slightly protruding.

A holding bracket 8 having a substantially L-shape in side view is formed integrally with the support bracket 6, and a portion extending upward and a portion extending horizontally of the holding bracket are formed as follows.
The extending end 7 of the support shaft in the extending direction of the portion
A fitting groove (lateral groove) facing the a side is formed. The groove width of the first fitting groove 9 formed in the portion extending upward of the holding bracket is the groove width in which the support bar 13 of the inner lid 11 described later fits exactly, and is formed in the horizontally extending portion. The groove width of the second fitting groove 10 is slightly wider than this.

The inner lid 11 is formed by a plurality of horizontal bars 12 and a plurality of vertical bars 13 and 14 including a support bar 13 which function as a handrail of a ladder when standing up. The base end of 13 is pivotally supported on the support shaft 7 so as to be freely movable in the axial direction. The two support bars 13 are respectively adjacent to the two holding brackets 8 on the side where the fitting grooves 9 and 10 are provided.

A spring receiving block 16 with a sleeve 15 is fixed at a position opposite to one of the support brackets of the support shaft 7 and a predetermined distance across the support bar 13 of the inner lid.
A compression coil spring 17 for urging the support bar 13 on the corresponding side toward the holding bracket 8 between the sleeve 15 and the support shaft 7.
Is installed. A pendulum-shaped lock member 18 is pivotally supported on the outer periphery of the sleeve 15 so as to be freely swingable and immovable in the axial direction. When the support bar 13 is fitted into the first fitting groove 9, the locking member 18 has a stopper pin 1 that is located with a slight clearance left on the surface of the support bar 13 on the side opposite to the fitting groove.
9 and a weight 20 for swinging the stopper pin upward are integrally formed. The upward movement position of the stopper pin 19 is defined at a position where the pendulum motion in which the weight 20 hangs down below the support shaft 7 is stopped by contact with the vertical side of the angular section member 33.

The fitting grooves 9 and 10 of the holding block have a groove depth enough to just fit the support bar 13, but the outer flange of each fitting groove, that is, the first fitting groove 9 The rear flange 21 and the lower flange 22 of the second fitting groove 10 protrude higher than the inner flanges 23 and 24. The spring receiving block 16 with the sleeve is fixed at a position where a gap is left between the tip of the sleeve 15 and the upper edge of the inner flange 23 so that the support bar 13 can pass with a play gap.

Positioning pins 25 project from both sides of the front end of the lattice-shaped inner lid 11 in a rectangular shape, and a receiving groove 26 for accommodating the positioning pins is formed in the outer frame 1 corresponding to the positioning pins 25. I have. As for the positioning pin 25, the inner lid 11 is
The support bar 13 is rotated around in the horizontal direction, and the support bar 13 is inserted into the second fitting groove 10 and then into the receiving groove 26. Figure 1
In the falling state of the inner lid 11 shown in (2) and (3), the inner lid closes the entrance of the manhole, and prevents articles larger than the grid of the lattice from falling into the manhole. Therefore, if the roughness of the grid is made smaller than the size of the foot of the person, it is possible to prevent the person from stepping into the manhole by mistake. Also, as shown in FIG. 7, if a fine grid or net is provided on the upper surface of the inner lid 11 in the lying state, it is possible to prevent smaller objects from falling into the manhole. The distal end side of the inner lid 11 is slightly lifted from the laid state, and the positioning pin 25 and the receiving groove 26 are lifted.
When the inner lid 11 is slid along the support shaft 7 against the urging force of the compression coil spring 17 after the disengagement of the Over the support shaft 7. In this state, the inner lid 11
Is rotated upward, the compression coil spring 17 is maintained in a compressed state by the contact between the support bar 13 and the inner flanges 23 and 24 of the fitting grooves 9 and 10 during the rotation period. 11
Can be rotated to the upright position where it fits into the first fitting groove 9. Immediately before the inner lid 11 reaches the upright position, the back surface of the support bar 13 abuts against the stopper pin 19 of the lock member, and reaches the upright position with the stopper pin 19 pushed rearward. The clockwise rotation of the lock member 18 in FIG.
3 and is blocked. When the inner lid 11 reaches the upright position, the support bar 13 is fitted into the first fitting groove 9 of the holding block by the urging force of the compression coil spring 17, and the upright state of the inner lid 11 is maintained. Since the contact between the support bar 13 and the stopper pin 19 of the lock member is released, the lock member 18 swings back and the stopper pin 19 is
Swings to the back side of. In this state, the axial movement of the inner lid, which attempts to disengage the support bar 13 from the first fitting groove 9, is prevented by the stopper pin 19, and even if a lateral external force is applied to the inner lid 11, 11 does not fall. In this upright state, the horizontal rail 12 of the inner lid becomes a handrail at the upper end of the ladder connected to the ladder or handrail provided inside the manhole. When the inner lid in the upright state is folded down, the stopper pin 19 of the locking device is pushed by hand to the rear side, and the inner lid 11 is slid on the support shaft in the state as it is, so as to be fitted to the support bar 13 and the first fitting. After the fitting with the groove 9 is released, the support bar 13 is pivoted downward around the support shaft 7 and the support bar 13 is fitted into the second fitting groove 10 at the lowered position.
Is inserted into. This lying state is basically maintained by the contact between the positioning pin 25 and the receiving groove 26. However, even if the positioning pin 25 is broken, there is an
Since the flange 22 below the second fitting groove 10 prevents the support bar 13 from rotating downward, there is no possibility that the inner lid 11 rotates downward and opens.

The lock member 18 of the above embodiment is of a pendulum type utilizing a weight 20. As shown in FIG. 4, the lock member 18 is biased by a tension spring 27 around a fulcrum pin provided separately from the support shaft. When the support bar is pushed by the support bar 13 of the inner lid that rotates upward, as shown in FIG. 5, or when the support bar is fitted into the first fitting groove 9, as shown in FIG. A lock mechanism having various structures such as a structure in which a stopper pin 30 protruding toward the back side of the support bar by the urging force of the spring 29 and a structure in which a stopper 31 for manually moving forward and backward as shown in FIG. 6 can be used. is there. Further, the angular section member 33 and the receiving groove 26 of the above embodiment can be provided in the inner frame 2.

[Brief description of the drawings]

FIG. 1 is a plan view of the apparatus of the present invention installed on a manhole frame.

FIG. 2 is a sectional side view of FIG.

FIG. 3 is an enlarged sectional view of a main part of FIG. 2;

FIG. 4 is a plan view showing another embodiment of the lock member.

FIG. 5 is a plan view showing still another embodiment of the lock member.

FIG. 6 is a side view showing still another embodiment of the lock member.

FIG. 7 is a sectional view showing another embodiment of a ladder.

[Explanation of symbols]

 7 Support shaft 8 Holding bracket 9 First fitting groove 10 Second fitting groove 11 Inner lid 12 Horizontal rail 17 Compression coil spring 18 Lock member

Claims (4)

[Claims] 1. A lattice-shaped inner lid (11) provided with a horizontal bar (12) that is capable of standing up and down and rotating around a horizontal support shaft (7) and parallel to the support shaft, Retaining bracket with lateral groove (9) that moves axially and engages the standing inner lid
(8), an urging means (17) for urging the inner lid (11) and the holding bracket (8) laterally in a direction for engaging the same, the engaged lateral groove (9) and the inner lid ( And a lock member (18) for preventing movement of the manhole in the disengagement direction. 2. The ladder and fall prevention device according to claim 1, wherein the holding bracket (8) is provided with a second lateral groove (10) which engages with the inner lid in the down state. 3. An inner lid (11) is supported by a support shaft (7) so as to be movable in the axial direction, and a biasing member (17) holds the inner lid (11).
(8), a support bracket (6) provided with lateral grooves (9, 10) oriented in the same direction on both axial sides of the support shaft (7), and the support shaft (7 3. The ladder and fall prevention device according to claim 1, wherein the support bracket is supported by the manhole frame at the position where the support bracket is disposed. 4. A cross rail (12) of the inner cover on the upper surface of the inner cover in a lying state.
4. The ladder and fall prevention device according to claim 1, 2 or 3, further comprising a grid plate or a mesh (32) having a smaller interval than the interval.