JP3180166U - Manhole fall prevention device - Google Patents

Abstract

[PROBLEMS] To provide an economic effect when it is possible to obtain a high effect of preventing the fall of articles and people into a manhole, but it is necessary to replace it together with a member supporting it for reasons such as damage. A fall prevention device capable of minimizing loss is provided.
A pair of brackets 2 and 2 fixed inside an adjustment ring 1 at the uppermost part of a manhole, and a base plate of both side plates 3 and 3 are connected to a connecting plate 2b of the brackets 2 and 2 for the length of the pin. And a guard member 5 that can be raised and lowered via a hole 3ph and a hinge pin 4. Further, both side plates 3, 3 constituting the guard member 5, a plurality of horizontal bars 7, 7,... Arranged in a state orthogonal thereto, auxiliary guard members 8, 8 arranged on both outer sides of the side plates 3, 3, and an adjustment ring 1 is provided with a front end support portion 6 fixed at a position facing the brackets 2 and 2 on the inner side of 1, and includes bending engagement portions 6 k and 6 k for elastically fitting the front crosspiece 7 of the guard member 5. And the tip support portion 6.
[Selection] Figure 1

Description

  This device is mounted on the manhole adjustment ring so that it can be raised and lowered.When the iron cover is removed and the upper part of the manhole is opened for the inspection and repair of the underground facilities, this is used except when the operator enters and exits. Prevents manholes from falling down to prevent people or objects from falling from the opening, and when the worker enters or exits the manhole, it can stand up and be used as the top of the ladder It relates to the device.

  Patent document 1 is an example of a proposal of this kind of technique, and relates to a ladder and fall prevention device for manholes. This is a grid-like inner lid provided with a horizontal rail parallel to the support shaft, which can stand up and turn around the horizontal support shaft arranged on the frame of the iron cover, and the shaft of the support shaft. A holding bracket having a lateral groove that engages with the standing inner lid by relative movement in the direction, and a biasing means that biases the inner lid and the holding bracket in a lateral direction; And a locking member that prevents movement of the lateral groove and the inner lid in the separating direction. In addition, the holding bracket includes a second lateral groove that engages with the fallen inner lid, and a lattice plate or a net having an interval smaller than the interval between the inner lids on the upper surface of the fallen inner lid. Sometimes it is a thing.

  Therefore, according to the manhole ladder and fall-preventing device of Patent Document 1, when this is stood up and the inner lid is engaged and fixed by the holding bracket, the lateral rail of the inner lid is used as the uppermost portion of the ladder of the manhole. It can be used effectively when entering and exiting the manhole, and if the inner lid and the holding bracket are disengaged and the inner lid is laid down, it is possible to prevent people and objects from falling into the manhole. Can do. In particular, when a lattice plate or a net having a narrower interval than the interval between the horizontal rails is arranged on the upper surface of the inner lid, it is possible to prevent a smaller article from falling.

  However, the ladder-cum-falling prevention device for a manhole disclosed in Patent Document 1 is attached to a frame for installing an iron lid that closes an opening of a manhole, and when a part or all of the damage occurs. In addition, if this is to be replaced, an expensive frame may need to be replaced.

  Patent Document 2 relates to a manhole cover receiving frame provided with an inner lid. In the case where the receiving frame holding the manhole cover includes an inner lid for preventing falling, the inner lid is formed in a lattice shape, Branch protrusions extending downward and obliquely upward are formed on both sides of both ends, and any of the branch protrusions is inserted into through holes formed at both ends of a step attached to the inner periphery of the receiving frame. In addition, a stopper insertion hole is formed in one end portion of the branching projection, and the stopper is inserted into the insertion hole so that the lattice-shaped inner lid can be locked in an open state.

  Therefore, according to the manhole cover receiving frame provided with the inner cover of Patent Document 2, even if the manhole cover is removed from the receiving frame, the inner cover is disposed below the manhole cover. There is no risk of falling inside. If the worker enters the manhole, remove the inner lid and replace the branching protrusion inserted into the through-hole of the step, and the inner lid will rise obliquely above the manhole, It can be used as a slide and a step to enter the manhole safely. After that, if the inner lid is arranged as it is, it is possible to prevent an object or a person from falling into the manhole in which the person is placed. Needless to say, when the worker leaves the manhole, the inner lid may be removed.

  On the other hand, the manhole cover receiving frame provided with the inner cover of Patent Document 2 literally has a configuration in which the inner cover is arranged on the manhole cover receiving frame. In the event of damage, attempting to replace them may require expensive replacement of the receiving frame.

Japanese Patent No. 4516672 Japanese Patent No. 2670994

  The present invention covers itself with an iron lid in order to minimize its economic loss when all or part of itself is damaged and replacement is required with the supporting members. Unlike the receiving frame, when the above-mentioned replacement is required, it is installed in a part where it can be economically realized, but it is equal to or more than the case where it is attached to the receiving frame. It is an object of the present invention to provide a manhole fall prevention device that can obtain a high effect of preventing falls of articles and people.

1 of the present invention is a pair of brackets fixed inside the adjustment ring constituting the uppermost part of the manhole,
A guard member that is disposed in the bracket so that it can be raised and lowered via hinge pins each having a base portion of both side plates penetrating through a long hole for a pin formed along the length direction of the side plate. A guard member provided with a plurality of horizontal rails connecting each other and an auxiliary guard member arranged on the outside of each of the side plates;
A tip support portion for supporting a tip of the guard member fixed to a position facing the pair of brackets inside the adjustment ring;
It is a manhole fall prevention device composed of

2 of the present invention is the manhole fall prevention device of 1 of the present invention.
A main long hole that is extended and opened at the base of the side plate of the guard member near the lower side of the side plate in the lying state, and a sub-hole that is opened by bending and extending the rear end upward. It is composed of.

3 of the present invention is the manhole fall prevention device of 2 of the present invention.
The auxiliary guard member is configured as a U-shaped member having two hook-shaped locking portions at intervals exceeding the thickness of the side plate at the base portions of both leg portions, and the front portion of the side plate is longer than the long hole for the pin. A main hole extending along the widthwise center of the side plate, and a U-shaped width of the U-shaped member constituting the auxiliary guard member centering on the lengthwise center of the side plate. A slot for an auxiliary guard member comprising a sub-hole extending downward at one position is formed, and the bases of both legs of the U-shaped member constituting the auxiliary guard member are slid to the slot for the auxiliary guard member. Insert freely, and position one of the two hook-shaped locking portions on the outer side of the side plate and the other on the inner side, respectively, to the slot for the auxiliary guard member at the base of the both leg portions. It is designed to ensure a slide insertion state.

4 of the present invention is a fall prevention device for manholes of 1, 2, or 3 of the present invention.
The tip support portion is a U-shaped member made of an elastic member in which the base portions of both leg portions are fixed to the adjustment ring, and the leading edge of the guard member is provided in the vicinity of the front portion of both leg portions. It is configured as a U-shaped member having a partially arc-shaped bent engagement portion so as to be fitted.

5 of the present invention is a manhole fall prevention device of 1, 2, 3 or 4 of the present invention.
Resin films are applied to both side plates, all cross rails and both auxiliary guard members constituting the guard member.

  According to the manhole fall prevention device 1 of the present invention, when an operator tries to enter the manhole, the iron cover at the top of the manhole is removed, and the manhole is attached to an adjustment ring directly below the receiving frame that supports the manhole. The guard member may be rotated upright with the hinge pin as the center of rotation. When the guard member is erected in this way, the hinge pin is inserted through a long hole for a pin that opens along the length direction of the base plate of the side plate. It will descend by its own weight until it is locked to the upper end of the pin hole. And since the base side of the both side plates comes into contact with the mounting means side of the bracket or the inner periphery of the adjustment ring, the guard member cannot be rotated reversely around the hinge pin. It can be used as a ladder on the top and can be safely used for descending entry into the manhole.

  After the operator enters the manhole, if the guard member is first lifted, the base will not abut against the inner periphery of the adjustment ring, and reverse rotation / falling operation is possible. The body is laid down and the tip side portion is supported by the tip support part. In this way, it is possible to prevent various articles and people from falling from above the guard member. As a result, safety around the manhole and the safety of workers in the manhole can be ensured.

  After completion of the work, if the guard member is stood up again with its tip side removed from the tip support portion, the worker in the manhole can safely use the steps disposed on the inner wall of the manhole and the guard member. You can go outside from the manhole.

  Further, according to the manhole fall prevention device of the present invention, since this is attached to the uppermost adjustment ring of the manhole, as described above, excellent fallen as in the case of being attached to the iron lid receiving frame. It is possible to ensure the prevention effect and usefulness as a ladder when an operator enters and exits the manhole, and at the same time, when all or part of it is damaged, as in the existing example Unlike the case of exchanging with the receiving frame for the iron lid, since it is exchanged with the adjustment ring, it is possible to exchange much more economically.

  According to the manhole fall prevention device 2 of the present invention, the guard member is pulled up, the hinge pin is positioned at the rear end of the main long hole of the pin long hole, and then the guard member is rotated to the lying down state. When operated, the guard member descends due to its own weight, and the hinge pin is naturally positioned at the uppermost portion of the auxiliary hole. As a result, even if the guard member continues to rotate with its tip end lowered, the lower side of the rear end of the base abuts against the mounting means side of the bracket or the inner periphery of the adjustment ring, and the rotation is prevented. Will be blocked. As described above, the front end side of the guard member is supported by the front end support portion. However, even at the rear end, the rotation operation that further lowers the front end side as described above is prevented. Will be. The effect of preventing the fall is further ensured.

  According to the manhole fall-preventing device of the present invention, when the guard member is in a lying state, the auxiliary guard member is inserted into the auxiliary hole in a state where both legs are inserted and locked. In view, the manhole is positioned at the center of both sides, and a more effective fall prevention effect can be obtained in combination with the fall prevention effect by the side plates and the horizontal rail of the guard member. Further, when the guard member is erected, the auxiliary guard member can be used by moving the auxiliary guard member in the main hole of the auxiliary guard member long hole to be positioned at an appropriate position.

  According to the manhole fall prevention device 4 of the present invention, the guard member in the lying state is a partially arc-shaped bending engagement in which the state-of-the-art lateral cross is formed on both legs of the U-shaped member which is the tip support portion. This is easy even if the uppermost iron cover has been removed due to a large amount of high pressure water that has entered from either of them due to bad weather such as typhoon or heavy rain. Therefore, it is possible to continuously prevent a person or an object from falling into a manhole.

  According to the manhole fall prevention device 5 of the present invention, since the resin film is applied to each component part of the guard member, when a person or an article falls on the guard member, the person or the article is damaged. Can be difficult.

(a) is a plan view of the manhole fall prevention device of one embodiment attached to the manhole adjustment ring, (b) is a cross-sectional view of the central portion of (a), (c) is near the tip support portion of (b) Enlarged view of. (a) is a side explanatory view of the manhole fall prevention device of the embodiment in a state where the guard member is erected (only the adjustment ring is cross-sectional), (b) is an enlarged view of the vicinity of the tip support part of (a), (c ) Is an enlarged view of the vicinity of the guard member of (a). (a) is a perspective view of a guard member and a bracket of a fall prevention device for manholes according to an embodiment, and (b) is a perspective view of a state in which the vicinity of the base part of the side plate of the guard member is separated from the bracket. (a) is a perspective view of a guard member and a bracket in a standing state of the manhole fall prevention device of one embodiment, and (b) is a perspective view in a state in which the vicinity of the base portion of the side plate and the bracket are separated when the guard member stands. (a) is an explanatory diagram of a manhole fall prevention device installed in a manhole and the guard member is erected (only the manhole cross section, receiving frame and iron cover are omitted), (b) is a manhole with the guard member lying down FIG. 4 is an explanatory view of the fall prevention device (only the manhole is omitted in cross section, receiving frame and iron lid).

  DESCRIPTION OF EMBODIMENTS A mode for carrying out the present invention will be described in detail based on an embodiment with reference to the drawings.

  As shown in FIGS. 1 to 5, the manhole fall prevention device of this embodiment basically includes a pair of brackets 2, 2 fixed inside the adjustment ring 1 constituting the uppermost portion of the manhole M, The brackets 2 and 2 are opposed to the pair of brackets 2 and 2 inside the adjustment ring 1 and a guard member 5 in which the base portions of the side plates 3 and 3 on both sides are arranged to be raised and lowered via hinge pins 4 and 4. And a tip support portion 6 fixed at a position to be fixed.

  As shown in FIGS. 5 (a) and 5 (b), the adjusting ring 1 is a concrete member that constitutes the uppermost portion of the manhole M. As shown in FIG. It is an annular member. It is also a member that can be manufactured at a lower cost than a receiving frame for installing an iron lid disposed on the adjustment ring 1. As described above, the manhole fall prevention device of the present invention is configured inside the adjustment ring 1.

  The brackets 2 and 2 have a curvature that matches the curvature of the inner periphery of the adjustment ring 1 as shown in FIGS. 1 (a), 3 (a), 3 (b) and 4 (a), 4 (b). This is a metal member (consisting of stainless steel in this embodiment) integrally composed of a mounting plate 2a configured as a partially arc-shaped band plate in plan view and a connecting plate 2b protruding from the inner center thereof. . A pin hole 2bh for penetrating the hinge pin 4 is opened at the center in the vertical direction of the connecting plate 2b, and screw holes 2ah are opened at the center on both the left and right sides of the mounting plate 2a.

  These brackets 2 and 2 are installed inside the adjustment ring 1 at intervals corresponding to the intervals between the side plates 3 and 3 of the guard member 5, as shown in FIG. More specifically, the brackets 2 and 2 are arranged at intervals that are in a positional relationship in which the connecting plates 2b and 2b come into contact with the outer surface sides of the side plates 3 and 3 of the guard member 5, respectively. As shown in the figure, the brackets 2 and 2 are fixed to the inner periphery of the adjustment ring 1 such that the outer surface of each mounting plate 2a abuts the inner periphery of the adjustment ring 1 and the screw holes 2ah, Concrete screws b and b are inserted from 2 ah, and screwed into a prepared hole previously opened in a corresponding portion of the adjustment ring 1 and fixed.

  The side plates 3, 3 are members constituting a part of the guard member 5 together with the cross rails 7, 7... And the auxiliary guard members 8, 8, and are shown in FIGS. 1 (a), 3 (a) and 4. As shown to (a), it comprised with the strip | belt-shaped metal plate material of the same dimension mutually arrange | positioned in parallel (This embodiment also used the stainless steel, the crosspieces 7 ... and the auxiliary guard members 8 and 8 are also the same). Is. The side plates 3 and 3 are respectively provided with a pin long hole 3ph and an auxiliary guard member long hole 3gh.

  As shown in FIGS. 3 (a), 3 (b), 4 (a), and 4 (b), the pin long hole 3ph has a main long hole 3phm and a sub hole 3phs that are formed in the base portions of the side plates 3 and 3, respectively. It is composed of As shown in the figure, the main long hole 3phm extends and opens close to the lower side of the side plates 3 and 3 when the guard member 5 is in a lying state, and the sub hole 3phs has the main long hole 3phm. The center of the uppermost portion of the sub-hole 3phs is approximately the center of the side plate 3 in the width direction.

  As shown in FIGS. 3A and 3B and FIGS. 4A and 4B, the auxiliary guard member long hole 3gh is located on the front side of the pin long hole 3ph of the side plates 3 and 3. The main hole 3 ghm and the sub-hole 3 ghs are formed as openings. As shown in the figure, the main hole 3ghm is extended and opened along the center in the height direction (the center in the width direction) of the side plates 3 and 3 when the guard member 5 is lying down, and the sub-hole 3ghs is Centering on the central part in the length direction of the side plates 3 and 3, the center of an auxiliary guard member 8, which will be described in detail later, is made to coincide with this, and is extended downward at two positions that coincide with the U-shaped width. Is.

  In this embodiment, the hinge pin 4 employs a stainless steel bolt member, and as shown in FIGS. 3 (a) and 4 (a), both side plates 3, 3 of the guard member 5 are used. The outer surface side of the base portion is brought into contact with the inner surface side of the connecting plates 2b and 2b of the brackets 2 and 2, and the hinge pins 4 and 4 are inserted from the pin holes 2bh and 2bh of the connecting plates 2b and 2b, respectively. The pin holes 3ph and 3ph formed in the side plates 3 and 3 that are in contact with each other are passed through, two nut members (made of stainless steel) are screwed to the opposite side of the hinge pins 4 and 4, and the inner nut member is Tighten and adjust to a slightly loose state, and use the outer nut member as a lock nut to fix the inner nut member in that position. Thus, the guard member 5 is attached to the brackets 2 and 2 so as to be raised and lowered. As shown in FIGS. 1A and 1B, the brackets 2 and 2 are fixed to the predetermined position on the inner periphery of the adjustment ring 1 at the intervals. .

  The guard member 5 has already been described, and as shown in FIGS. 1 (a), 3 (a) and 4 (a), two parallel side plates 3 and 3 are connected to both ends at these ends. , And four auxiliary rails 7, 7... That are orthogonal to each other and the auxiliary guard members that are locked to the outside of the side plates 3, 3 via the auxiliary guard member long holes 3 gh, 3 gh formed in the side plates 3, 3. It consists of guard members 8 and 8.

  As shown in FIGS. 1 (a), 3 (a) and 4 (a), the auxiliary guard members 8 and 8 are provided with hook-shaped locking portions 8k and 8k at the bases of both leg portions 8l and 8l. It is configured as a U-shaped member, and the base portions of both leg portions 81 and 81 are inserted into the auxiliary guard member long holes 3gh and 3gh of the side plates 3 and 3 so as to be slidable. As shown in FIG. 1 (a), the hook-shaped locking portions 8k and 8k have the base ends of the leg portions 8l and 8l of the auxiliary guard members 8 and 8, and the thickness of the side plates 3 and 3 from the base ends. A slightly larger dimension is arranged on the inner part, and the base end is fixed by welding or the like after the legs 8l and 8l are inserted into the elongated holes 3gh and 3gh for the auxiliary guard member. Is.

  As shown in FIGS. 1 (a) to 1 (c), 2 (a), 2 (b), and 5 (a), the tip support portion 6 has the pair of inner sides of the adjustment ring 1. An elastic metal member (configured with elastic stainless steel in this embodiment) fixed at a position facing the brackets 2 and 2. Specifically, the tip support portion 6 is a U-shaped member that fixes the base portions of both leg portions 6l and 6l to the inner periphery of the adjustment ring 1 as shown in FIG. As shown in FIGS. 1B and 1C and FIGS. 2A and 2B, the guard members 5 and 6l are provided in the vicinity of the front bar 6r. Bending engagement portions 6k, 6k configured to be bent in a partial arc shape so that the state-of-the-art horizontal rail 7 can be fitted are arranged.

  Of the above members, resin plates are applied to the side plates 3 and 3, all the cross rails 7, 7... And both auxiliary guard members 8 and 8 of the guard member 5.

  Therefore, the fall prevention device of the manhole of this embodiment is attached to the adjustment ring 1 constituting the uppermost portion of the manhole M as described above, and particularly as shown in FIGS. 5 (a) and 5 (b). The circumferential position of the adjusting ring 1 is adjusted so that the brackets 2 and 2 are vertically corresponding to the steps s, s... Fixed to the inner circumference below the manhole M. Adjust it.

  As described above, when the manhole fall prevention device of this embodiment is set in the manhole M, it can be usefully operated as follows and can exhibit excellent effects.

  When an operator wants to enter the manhole M, a guard member attached to the adjustment ring 1 immediately below a receiving frame (not shown) supporting the same is removed from the uppermost iron cover of the manhole M. 5 may be rotated upright about the hinge pin 4 as a rotation center.

  When the iron cover of the manhole M is removed, as shown in FIGS. 1A, 1B, and 5B, the guard member 5 is in a lying state and its state-of-the- Are engaged and fixed to the bent engaging portions 6k and 6k formed on the both leg portions 6l and 6l of the tip support portion 6, respectively.

  For example, when the guard member 5 grasps the cutting edge horizontal beam 7 and pulls it up strongly, the horizontal beam 7 is elastically fitted to the partial arc-shaped portions constituting the bending engagement portions 6k and 6k. Therefore, it is possible to open the partial arc-shaped portion and remove it. Thereafter, the standing operation can be performed by simply pulling up the distal end side of the guard member 5 in a rotating state.

  When the guard member 5 is erected in this way, the hinge pin 4 is passed through the long pin hole 3ph opened at the base of the side plates 3 and 3, and when the guard member 5 is in the lying state, FIG. As shown in b) and FIG. 3 (a), the guard member 5 is inserted into the sub-hole 3phs of the long hole 3ph for the pin, so that the guard member 5 is shown in FIGS. As shown in FIGS. 5A and 5A, the hinge pin 4 is lowered by its own weight until it is locked to the upper end of the main long hole 3phm of the pin long hole 3ph.

  As a result, when the guard member 5 tries to reversely rotate the guard member 5 around the hinge pins 4, 4, the rear side of the base portions of the side plates 3, 3 is attached to the mounting plate 2 a of the bracket 2 or the Since it comes into contact with the adjusting ring 1, it becomes impossible, and the guard member 5 can be used safely as a lowermost approach to the manhole M by using it as the uppermost ladder.

  After the worker enters the manhole M, if the guard member 5 in a standing state is pulled up, the base portion, particularly the lower side thereof, is attached to the mounting plates 2a and 2a of the brackets 2 and 2 even if the guard member 5 is rotated in the reverse direction. Or it does not contact | abut to the inner periphery of the adjustment ring 1, and it becomes possible. Therefore, after the guard member 5 is pulled up in this manner, as shown in FIG. 3 (a), the guard member 5 is brought into a reverse rotation state, as shown in FIGS. 1 (a) to 1 (c) and FIG. 5 (b). Further, the horizontal rail 7 at the tip is fitted to and supported by the bending engagement portions 6k and 6k of both the leg portions 6l and 6l of the tip support portion 6.

  According to the manhole fall prevention device of this embodiment, as described above, the guard member 5 in the standing state is pulled up, and the hinge pins 4 and 4 are moved to the rear ends of the main long holes 3phm and 3phm (the standing state of the guard member 5). When the guard member 5 is rotated in the lying state after being positioned at the lower end, the guard member 5 is lowered by its own weight, and the hinge pins 4 and 4 are naturally positioned at the uppermost part of the auxiliary holes 3phs and 3phs. It becomes. As a result, when the guard member 5 further continues to rotate with its tip end lowered, the lower side of the rear end of the base portion contacts the mounting plates 2a, 2a of the brackets 2, 2, or the inner periphery of the adjustment ring 1. In contact with it, further rotation is prevented. As described above, the guard member 5 is fitted and held by the bending engagement portions 6k and 6k of the front end support portion 6 at the front end side crosspiece 7 but at the rear end as described above. Thus, the rotation of the tip end descending further is prevented.

  Thus, the guard member 5 can further prevent various articles and people from falling from above. As a result, the safety around the manhole M and the safety of the workers in the manhole M can be ensured.

  After the work is finished, if the guard member 5 is turned upright again after removing the state-of-the-art horizontal beam 7 from the bending engagement parts 6k, 6k of both the leg parts 6l, 6l of the tip support part 6, An operator in the manhole M can safely go out of the manhole M by using the steps s, s... Arranged on the inner wall of the manhole M and the cross rails 7, 7.

  Further, according to the manhole fall prevention device of this embodiment, since it is attached to the adjustment ring 1 at the top of the manhole M as described above, as in the conventional device of this type, It is possible to ensure the same excellent fall prevention effect as when attached to the receiving frame for the lid and usefulness as a ladder when an operator enters and exits the manhole M, and at the same time, all or part thereof When damage occurs, it is replaced with the adjustment ring 1 as compared with the case where it is replaced with the receiving frame for the iron lid as in the existing example, so that much more economical replacement is possible. It is.

  According to the manhole fall prevention device of this embodiment, when the guard member 5 is in a lying state, the auxiliary guard members 8 and 8 are connected to the leg portions 8l and 8l into the sub-holes 3ghs and 3ghs. By being in the insertion locking state, it can be positioned at the center of both sides of the manhole M in a plan view, and in combination with the guard member 5, a more effective fall prevention effect can be obtained. When the guard member 5 is erected, the auxiliary guard members 8, 8 are moved in the main holes 3ghm, 3ghm of the auxiliary guard member elongated holes 3gh, 3gh with respect to the legs 8l, 8l. The members 8, 8 can be moved to an appropriate position for use.

  Further, according to the manhole fall prevention device of this embodiment, the guard member 5 in the lying state is a partial circle in which the most advanced lateral crosspiece 7 is formed on the two leg portions 6l and 6l of the U-shaped member of the tip support portion 6. The arc-shaped bent engaging portions 6k and 6k are in a fitted state. Therefore, even in bad weather such as typhoon or heavy rain, even if a large amount of high pressure water that intrudes from one of them is ejected from the manhole M and the top iron cover comes off, it can easily fall off. There is no such thing as standing up. Therefore, it is possible to prevent a person or an object from falling into the manhole M continuously and reliably.

  In addition, according to the manhole fall prevention device of this embodiment, since the side plates 3, 3, the cross rails 7, 7,... And the auxiliary guard members 8, 8 constituting the guard member 5 are coated with resin, When a person or an article falls, the person or article can be hardly damaged.

DESCRIPTION OF SYMBOLS 1 Adjustment ring 2 Bracket 2a Mounting plate 2ah Screw hole 2b Connecting plate 2bh Pin hole 3 Side plate 3gh Slot for auxiliary guard member 3ghm Main hole 3ghs Sub hole 3ph Pin slot 3phm Main slot 3phs Sub hole 4 Hinge pin 5 Guard member 6 Tip support part 6k Bending engagement part 6l Leg part 6r Horizontal bar part 7 Horizontal bar 8 Auxiliary guard member 8k Hook-shaped locking part 8l Leg part b Concrete screw M Manhole s Step

Claims (5)

A pair of brackets fixed inside the adjustment ring constituting the uppermost part of the manhole,
A guard member that is disposed in the bracket so that it can be raised and lowered via hinge pins each having a base portion of both side plates penetrating through a long hole for a pin formed along the length direction of the side plate. A guard member provided with a plurality of horizontal rails connecting each other and an auxiliary guard member arranged on the outside of each of the side plates;
A tip support portion for supporting a tip of the guard member fixed to a position facing the pair of brackets inside the adjustment ring;
A manhole fall prevention device composed of   A main long hole that is extended and opened at the base of the side plate of the guard member near the lower side of the side plate in the lying state, and a sub-hole that is opened by bending and extending the rear end upward. The manhole fall-preventing device according to claim 1, comprising:   The auxiliary guard member is configured as a U-shaped member having two hook-shaped locking portions at intervals exceeding the thickness of the side plate at the base portions of both leg portions, and the front portion of the side plate is longer than the long hole for the pin. A main hole extending along the widthwise center of the side plate, and a U-shaped width of the U-shaped member constituting the auxiliary guard member centering on the lengthwise center of the side plate. A slot for an auxiliary guard member comprising a sub-hole extending downward at one position is formed, and the bases of both legs of the U-shaped member constituting the auxiliary guard member are slid to the slot for the auxiliary guard member. Insert freely, and position one of the two hook-shaped locking portions on the outer side of the side plate and the other on the inner side, respectively, to the slot for the auxiliary guard member at the base of the both leg portions. The manhole fall prevention device according to claim 2, wherein the insertion state is slidable. .   The tip support portion is a U-shaped member made of an elastic member in which the base portions of both leg portions are fixed to the adjustment ring, and the leading edge of the guard member is provided in the vicinity of the front portion of both leg portions. The manhole fall prevention device according to claim 1, 2 or 3, wherein the U-shaped member comprises a partially arc-shaped bent engagement portion so as to be fitted.   5. The manhole fall prevention device according to claim 1, wherein a resin film is applied to both side plates, all side rails and both auxiliary guard members constituting the guard member.

Images