JP4516672B2 - Manhole ladder and fall prevention device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fall prevention device provided in a manhole frame. When a cover plate closing the manhole is removed, the fall of the instrument into the manhole is prevented, and at the time of entering and exiting the manhole. The present invention relates to the above apparatus having a grid-like inner lid that also functions as a ladder.
[0002]
[Prior art]
Manholes are provided as maintenance inspection passages to underground sewers and wiring facilities, and are usually open on the ground surface of roads, etc., and cast iron lids that seal the holes (holes) in the openings A plate is provided. Inspecting and repairing underground facilities is done by opening the heavy cast iron cover plate and the operator entering the manhole, but the cover plate is usually left open during work. Therefore, if a large tool or the like is accidentally dropped into the manhole during this work, there is a risk of harming underground facilities and workers. In addition, if the underground space connected to the manhole is installed on a sloping ground, the water that flows into the underground space at a high place in the event of a flood or the like is caused by the difference in water level on the cover plate of the manhole provided in the low place. Internal pressure may act and cause the lid plate to jump off. When the manhole cover plate is opened due to such a phenomenon, there is a danger that a man will fall into the manhole, and the risk is particularly great during a flood where the manhole is submerged.
[0003]
Therefore, in order to prevent such a danger, a wire net that prevents the fall of the equipment is installed in the manhole, or the fall ladder is placed in a state where the fall of the equipment into the manhole or a person falls. It has been proposed to prevent. The manhole is provided with ladders or handrails for people to enter and exit, but the above-described tilting ladder forms the upper end portion of the ladder that protrudes to the ground surface when it stands up. By making the width wider than the necessary width as a ladder, it becomes a coarse lattice-shaped inner lid that closes the opening of the manhole when lying down.
[0004]
In the tilting ladder that also serves as the latticed inner lid of the manhole, when a large internal pressure is applied to the manhole in the lying state, the inner lid stands up at the same time as the lid plate jumps, and as a protective lid In order to avoid the function of being unable to function, a structure with a locking mechanism that locks the inner lid in a lying state, or a standing ladder to prevent its falling when standing up and used as a ladder Has already been proposed (see Japanese Patent Application Laid-Open No. 11-107303, for example).
[0005]
[Problems to be solved by the invention]
However, the conventionally proposed structure requires separate locking mechanisms for holding the standing state and holding the lying state, and there is a problem that the number of parts increases and the cost is high, and the ladder is guided. In a structure that falls into the position and keeps standing, the entire ladder must be lifted when releasing the lock.Therefore, when a sturdy ladder is installed in a large manhole, the ladder becomes heavy, and arm strength is required when unlocking. In addition, there is a problem that if the ladder rattling is reduced, the drop stroke must be increased.
[0006]
This invention is a manhole provided with a tiltable inner lid that can be used as a ladder when standing up, and its fall and standing operations are easy, the standing state can be safely and securely held, and the release can also be released It is an object of the present invention to provide a mounting structure for an inner lid of a manhole that does not require a large arm force and can be held in a standing state and a lying state with a simple structure.
[0007]
[Means for Solving the Problems]
The fall-prevention device for both manholes and ladders according to the present invention comprises a lattice-shaped inner lid 11 provided with a horizontal rail 12 which can stand and turn around a horizontal support shaft 7 and is parallel to the support shaft, and the support shaft. Holding bracket 8 provided with a lateral groove 9 that is relatively moved in the axial direction to engage with the standing inner lid, and a biasing means that biases laterally in a direction in which the inner lid 11 and the holding bracket 8 are engaged. 17 and a locking member 18 that prevents the engaged lateral groove 9 and the inner lid 11 from moving in the disengaging direction.
[0008]
The holding bracket 8 can be provided with a second lateral groove 10 that engages with the inner lid 11 in a lying state, and in the structure in which the lateral groove 9 and the second lateral groove 10 are provided integrally with the holding bracket 8, The urging force of one urging member can hold the inner lid upright and hold it in a lying state, and this holding bracket 8 is provided with lateral grooves at both ends of the support shaft 7 that pivotally supports the inner lid 11. According to the structure in which the directions 9 and 10 are provided in the same direction, the inner lid can be held and released on both the left and right sides in one operation.
[0009]
Incidentally, lateral grooves 9 and 10 of the holding bracket under the second lateral groove 10 to hold the collar 21 and the inclined state behind side of the transverse grooves 9 to hold the upright (back side of the inner lid of upright) Acting as a stopper for preventing the inner lid 11 from rotating from the standing position and downward from the lying position by making the side collar 22 larger than the axial movement stroke of the inner lid 11 at the time of disengagement Can be given.
[0010]
As the lock mechanism 18 for fixing the axial movement of the support shaft of the inner lid 11 in the standing state, various structures such as the gravity pendulum type, the spring rotation type, the spring advance / retreat type, and the ratchet claw type shown in the illustrated embodiment are used. Can be adopted.
[0011]
In addition, by providing a fine grid plate or net on the upper surface of the inner lid 11 in a lying state, it has a function to prevent small objects from falling into the manhole without impairing the function as a ladder when standing up. Can be made.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the examples 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 within the outer frame and that can be fixed in a lifted position, and the inner frame 2 is raised and lowered according to the height of the road surface. Although the manhole height can be adjusted in accordance with the height of the ground surface (including tilting), illustration and description of the lifting and fixing structure of the inner frame 2 are omitted.
[0013]
The inner peripheral upper surface of the inner frame 2 is a tapered hole, and the lid plate 3 made of cast iron is fitted into the tapered hole by a wedge action. On the lower surface of the outer frame 1, a square cross-section member 33 is formed in a rod 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 open cover plate 3 is loosely connected to the inner frame 2 by a connecting lever 4 suspended on the lower surface of one circumference. The upper end of the connecting lever 4 and the cover plate 3 are pivotally attached to each other by a horizontal pin 5 so as to be relatively swingable. Two support brackets 6 are integrally attached to the square cross-section member 33 with bolts 34 on both sides of a portion where the connecting lever 4 is movably held at a predetermined interval. 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 protrudes slightly.
[0014]
A holding bracket 8 that is substantially L-shaped 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 extended in the extending direction of the portion. A fitting groove (lateral groove) facing the protruding end 7a side of the shaft is formed. The groove width of the first fitting groove 9 formed in the portion extending above the holding bracket is a groove width in which a support bar 13 of the inner lid 11 described later is just fitted, and is formed in a portion extending horizontally. The groove width of the second fitting groove 10 is slightly wider than this.
[0015]
The inner lid 11 is formed by a plurality of horizontal rails 12 that function as ladder railings when standing and a plurality of vertical rails 13 and 14 including support rails 13. The end is pivotally supported on the support shaft 7 so as to be rotatable and axially movable. Each of the two support bars 13 is adjacent to the side where the fitting grooves 9 and 10 of the two holding brackets 8 are provided.
[0016]
A spring receiving block 16 with a sleeve 15 is fixed at a position facing a predetermined distance across one support bracket of the support shaft 7 and a support bar 13 of the inner lid, and between the sleeve 15 and the support shaft 7. A compression coil spring 17 for urging the support bar 13 on the side toward the holding bracket 8 is mounted. A pendulum-shaped lock member 18 is supported on the outer periphery of the sleeve 15 so as to be freely swingable and not movable in the axial direction. The lock member 18 includes a stopper pin 19 that is positioned with a slight gap left on the surface of the support bar 13 on the side opposite to the fitting groove when the support bar 13 is fitted into the first fitting groove 9. A weight 20 for swinging the stopper pin upward is 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 is about to hang down below the support shaft 7 is stopped by contact with the vertical side of the square cross-section member 33.
[0017]
The fitting grooves 9 and 10 of the holding block have a groove depth that just fits the support bar 13, but the outer side of each fitting groove, that is, the rear side of the first fitting groove 9. The lower flange 22 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 leaving a gap through which the support bar 13 can pass with a gap between the tip of the sleeve 15 and the upper edge of the inner flange 23.
[0018]
Positioning pins 25 project in a square shape on both sides of the front end of the lattice-shaped inner lid 11, and receiving grooves 26 for receiving the positioning pins are formed in the outer frame 1 corresponding to the positioning pins 25. The positioning pin 25 is inserted into the receiving groove 26 after the inner lid 11 rotates in the horizontal direction around the support shaft 7 and the support bar 13 is inserted into the second fitting groove 10. 1 and 2, 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 lattice is made smaller than the size of the person's foot, it is possible to prevent the person from stepping into the manhole. Further, as shown in FIG. 7, if a fine grid or net is provided on the upper surface of the inner lid 11 in a lying state, it is possible to prevent a smaller item from falling into the manhole. The tip end side of the inner lid 11 is slightly lifted from this lying down state, the fitting between the positioning pin 25 and the receiving groove 26 is removed, and then the inner lid 11 is attached to the support shaft 7 against the urging force of the compression coil spring 17. When it is slid along, the support bar 13 gets over the flange 24 inside the second fitting groove 10 and can turn around the support shaft 7. When the inner lid 11 is rotated upward in this state, the compression coil spring 17 is compressed 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. And the inner lid 11 can be rotated to the standing position where the inner lid 11 is fitted in the first fitting groove 9. Immediately before the inner lid 11 reaches the standing position, the rear surface of the support bar 13 comes into contact with the stopper pin 19 of the lock member and reaches the standing position in a state where the stopper pin 19 is pushed backward. The unnecessary rotation of the lock member 18 in the clockwise direction in FIG. 2 is prevented by the protrusion 36 integral with the lock member coming into contact with the upper surface of the square cross-section member 33. When the inner lid 11 reaches the standing 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 standing 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 moved to the back side of the support bar 13 ( the back side of the support bar 13 viewed from the holding bracket 8 side). (See Fig. 3) . In this state, the stopper lid 19 prevents the inner lid from moving in the axial direction so as to disengage the support bar 13 from the first fitting groove 9, and even if a lateral external force is applied to the inner lid 11, the inner lid 11 never falls. In this standing 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 standing state is laid down, the stopper pin 19 of the locking device is pushed by hand to the back side of the inner lid, and the inner lid 11 is slid on the support shaft as it is, so that the 1 is disengaged from the fitting groove 9 and rotated downward around the support shaft 7, and after the support bar 13 is fitted into the second fitting groove 10 at the lying position, the positioning pin 25 is It is inserted into the receiving groove 26. This lying down state is basically maintained by the contact between the positioning pin 25 and the receiving groove 26, but even if there is an accident such as breakage of the positioning pin 25, the lower position of the second fitting groove 10 is maintained. Since the rod 22 prevents the support bar 13 from rotating downward, there is no possibility that the inner lid 11 rotates downward and opens.
[0019]
The lock member 18 of the above embodiment is of a pendulum type using a weight 20, but as shown in FIG. 4, it is rotated by a biasing force of a tension spring 27 around a fulcrum pin provided separately from the support shaft. When the structure is provided with the hook 28 or when the support bar is inserted into the first fitting groove 9 by being pushed by the support bar 13 of the inner lid that rotates upward as shown in FIG. Various structures such as a structure in which a stopper pin 30 that protrudes toward the back side of the support bar ( back side as viewed from the holding bracket side) by a biasing force of the support bar, or a structure in which a stopper 31 that is manually advanced and retracted as shown in FIG. The locking mechanism can be used. Further, the angular cross-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 an apparatus according to the present invention installed on a manhole frame. FIG. 2 is a sectional side view of FIG. 1. FIG. 3 is an enlarged sectional view of a main part of FIG. 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 cross-sectional view showing another embodiment of the ladder. Explanation of symbols]
7 Support shaft 8 Holding bracket 9 First fitting groove
10 Second mating groove
11 Inner lid
12 side pier
17 Compression coil spring
18 Locking member

Claims (4)

A lattice-shaped inner lid (11) having a horizontal rail (12) that can stand up and turn around a horizontal support shaft (7) and is parallel to the support shaft, and a relative movement in the axial direction of the support shaft The holding bracket (8) having a lateral groove (9) that engages with the standing inner lid, and the biasing that biases laterally in the direction in which the inner lid (11) and the holding bracket (8) are engaged. Manhole ladder and fall prevention device comprising a biasing means (17), and a locking member (18) for preventing movement of the engaged lateral groove (9) and the inner lid (11) in the disengagement direction. . The ladder and fall-preventing device according to claim 1, wherein the holding bracket (8) includes a second lateral groove (10) that engages with the inner lid in a lying state. The inner lid (11) is supported by the support shaft (7) so as to be movable in the axial direction, and the biasing member (17) biases the inner lid (11) toward the holding bracket (8). Support bracket (6) with lateral grooves (9, 10) facing in the same direction is provided on both sides in the axial direction, and the support shaft (7) is supported by the manhole frame at the position of the support bracket. The ladder-cum-falling prevention device according to claim 1 or 2, characterized in that: 4. The ladder and fall-preventing device according to claim 1, further comprising a lattice plate or a net (32) having an interval narrower than an interval between the inner lid horizontal rails (12) on the upper surface of the inner lid in a lying state.

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