JP2010261189A - Safe work fence body for manhole, having device for fixation to manhole cover frame, and device for fixing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a safe work fence body for being mounted in an opening of a manhole, the installation work of which can be rapidly performed with ease, which can be surely engaged with a manhole cover frame, which cannot be easily disengaged therefrom, and the removal work of which can be rapidly performed with ease. <P>SOLUTION: In a fixing device for being mounted at the lower end of the safe work fence body for the manhole, a latch member, which has a flange-like member for being engaged with a receiving shelf for the manhole lid frame, is arranged in a frame body in an elastically returnable manner. The latch member performs a pull-in operation by receiving a pressing force from the receiving shelf in insertion into the manhole cover frame, and performs the operation of overhanging to the undersurface of the receiving fence when reaching an installation position. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a safety work fence body for a human hole that is installed for safety in a human hole cover frame that is opened when a work is performed in a human hole, that is, a manhole. The present invention relates to a fixing device that engages with a human hole lid frame.

An apparatus for ensuring the safety of workers in and out of a human hole is known from Japanese Utility Model Laid-Open No. 7-23085 (hereinafter referred to as prior art).
The manhole work safety device of the prior art (the reference sign indicates that in the publication) is inclined toward the center with respect to the lower ring 1 having the same outer diameter as the outer diameter of the manhole cover and the lower ring 1. A notch upper ring 3 having a smaller diameter than that connected by a plurality of slant rods 2 and a grip bar 5 provided on the lower ring 1 in the notch portion 4 of the upper ring 3. The nail | claw 7 for detachment prevention is suspended.
In the use of the prior art work safety device, the manhole cover is removed, the lower ring 1 of this device is fitted into the manhole frame, and the operator can insert the upper ring 3 and the grip rod 5 from the notch 4 of the upper ring 3. Grab the inside of the manhole, step into the manhole and step into the manhole.
However, in the prior art, the locking claw 7 is simply attached to the lower ring 1, and the locking function is uncertain, and does not perform a special function. . In other words, the anti-separation claw 7 is shallow as shown in the figure, has a weak engagement with the manhole frame, and is easy to come off.

Japanese Utility Model Publication No. 7-23085

The present invention has been made in view of the above circumstances, and in the operation of a human hole, in the safety work fence for a human hole installed on the human hole cover frame, the installation is made quickly and easily and the human hole It is an object of the present invention to provide a safety work fence for manholes that can be reliably engaged with the lid frame and cannot be easily detached, and that can be quickly and easily removed.
For this reason, the present invention achieves this object by adding a latch mechanism for locking the shelf of the manhole cover frame to a fixing device attached to the lower end of the safety work fence body for manholes. .

The present invention specifically adopts the following configuration.
(First invention)
The first invention relates to a safety work fence for a manhole having a fixing device, and as described in claim 1,
A fixing device is attached to one or a plurality of locations at the lower end of the safety work fence for manholes installed in the opened manhole cover frame,
The fixing device is
A frame body that retains rigidity and has a smaller diameter than the inner diameter of the shelf of the installed manhole cover frame is fixed to the lower end of the manhole safety work fence body,
It is attached via the frame body, receives an elastic action, has a diameter larger than the inner diameter of the receiving hole of the manhole cover frame in which the bowl-shaped member is installed in a steady state, and can be engaged with the receiving rack A latch member that takes a state;
When the latch member is inserted into the manhole cover frame to be installed, the latch member receives a pressing force from the inner peripheral surface of the receiving shelf of the manhole cover frame and receives a pull-in operation against its elastic action. When the installation position is reached, the hook-shaped member is detached from the inner peripheral surface of the receiving shelf and performs an overhanging operation on the lower surface of the receiving shelf.
It is characterized by that.
In the above configuration, the “frame body”, that is, the machine frame, is a rigid base material for mounting other functional members of the fixing device. In the present embodiment, the casing of a square box is adopted, but the embodiment is limited to this mode. It is not something.
The “steady state” refers to a state taken when the latch member receives no other urging force other than the urging means related to the latch member.
The “predetermined installation position” takes the upper surface of the main body of the manhole cover frame, the upper surface (receiving surface) of the receiving shelf, and other appropriate positions.
In the present invention,
1. This fixing device is normally arranged in two places symmetrically at the lower end of the safety work fence for manholes,
2. An inclined surface is formed on the lower surface of the bowl-shaped member,
3. A roller is disposed on the lower surface of the bowl-shaped member,
Is a technical matter that is adopted as appropriate.

(Function)
In the installation of the safety work fence body for the person's hole, the fixing device is simultaneously installed so that the lower end surface of the safety work fence body is placed on the upper surface of the opened human hole cover frame or the upper surface of the receiving shelf. Insert it into the inner surface of the frame.
At this time, the latch member of the fixing device receives a pressure from the inner peripheral surface of the receiving shelf of the manhole cover frame from a steady state and receives a pulling operation against its elastic action, thereby facilitating the inner periphery of the receiving shelf. To pass through. This pull-in operation is performed by the inclined surface of the lower surface of the bowl-shaped member or a roller disposed together with the roller, but does not prevent other measures from being taken. When the lower end surface of the safety work fence body reaches a predetermined installation position, the safety work fence body is detached from the inner peripheral surface of the receiving shelf, and the hook-like member extends to the lower surface of the receiving shelf. That is, the latch member returns to a steady state, and is in an engaged state, that is, a locked state with a receiving shelf of the manhole cover frame.
Thereby, the safety work fence body for the person's hole is stably installed without coming out upward.
To remove the safety work fence body for the person hole, the latch member of the fixing device is pulled from the steady state against the elastic action, and the safety work fence body for the person hole is pulled upward. At this time, the latch member of the fixing device is disengaged from the receiving shelf of the human hole cover frame, and the personal hole safety work fence is easily removed from the human hole cover frame.

(Second invention)
In the first invention, each latch member has one hook-like member having a different height, and a latch member (latch A) having a hook-like member having a low height has a high hook-like member (latch). It is the second aspect of the present invention that B) is constrained only for backward movement.
In the above configuration, the latch A is restrained by the push rod in the following embodiments, but is not limited to this.
(Function)
According to the second aspect of the invention, the operation of the latch member differs depending on the thickness of the shelf for the human hole lid frame.
That is, when the thickness of the socket for the manhole cover frame is thin, all of the plurality of latch members pass through the inner peripheral surface of the rack for the manhole cover frame and have a latch member having a high bowl-shaped member. Engage with the shelf. When the thickness of the shelf of the manhole cover frame is thick, the latch member having a low-profile hook-shaped member passes through the inner peripheral surface of the socket of the manhole cover frame and has a high hook-shaped member. Keeps being pushed by the inner peripheral surface of the shelf. As a result, a latch member having a low hook-like member is engaged with the receiving shelf.

(Third invention)
In the first or second aspect of the invention, the hook-like member (the tip) of the latch member is positioned more than the inner peripheral surface of the shelf of the human hole lid frame against the elastic action in a steady state. Adopting a configuration having a lock release mechanism that continuously releases the retractable state to be retracted constitutes the third invention.
The lock release mechanism is not limited to the structure shown in the following embodiment as long as it has a function of continuously releasing the engageable state.
(Function)
According to the third aspect of the present invention, the removal operation of the safety work fence body for the person's hole is easily performed.
That is, in removing the safety work fence body for the person hole, when the lock release mechanism is operated, the hook-shaped member of the latch member takes a state of continuously retracting from the inner peripheral surface of the shelf of the person hole cover frame, The latch member is disengaged from the receptacle of the manhole cover frame. Then, when the safety work fence body for the person hole is pulled upward, the safety work fence body for the person hole is easily removed from the human hole cover frame.

(Fourth invention)
This 4th invention relates to the fixing device of the safety work fence body for manholes, As described in claim 4,
A fixing device attached to the lower end of the safety work fence for manholes installed in the opened manhole cover frame,
A frame body that retains rigidity and has a smaller diameter than the inner diameter of the shelf of the installed manhole cover frame is fixed to the lower end of the manhole safety work fence body,
It is attached via the frame body, receives an elastic action, has a diameter larger than the inner diameter of the receiving hole of the manhole cover frame in which the bowl-shaped member is installed in a steady state, and can be engaged with the receiving rack A latch member that takes a state;
When the latch member is inserted into the manhole cover frame to be installed, the latch member receives a pressing force from the inner peripheral surface of the receiving shelf of the manhole cover frame and receives a pull-in operation against its elastic action. When the installation position is reached, the hook-shaped member is detached from the inner peripheral surface of the receiving shelf and performs an overhanging operation on the lower surface of the receiving shelf.
It is characterized by that.
(Function)
The operation of the safety work fence for manholes equipped with the fixing device is in accordance with the first invention.

(Fifth invention)
The fifth aspect of the invention also relates to a fixing device for a safety work fence for a manhole, as described in claim 5,
A fixing device attached to the lower end of the safety work fence for manholes installed in the opened manhole cover frame,
1) The upper part is fixed to the safety work fence body for manholes, has at least a flat front plate, and includes a frame body in which a rectangular window is opened on the front plate,
2) A plate body that fits into the window portion of the frame body is arranged so as to be able to elastically recover against a backward fall through an elastic hinge fixed to the lower edge of the window portion, and the plate body 1 or a plurality of latch portions in which a housing projecting forward is fixed to the front surface of
3) In the latch portion at the end, a lock release lever is erected on the upper surface, and a lock pin engagement hole is opened on the side end surface,
4) Arranged side by side with the latch part,
a) only a movement in the axial direction is allowed, and a lock pin fitted into the lock pin engagement hole with a biasing force in response to a predetermined tilting movement to the rear of the latch part;
b) a holding frame attached to the frame body and holding the lock pin;
c) A lock pin pull back mechanism that pulls back the lock pin in conjunction with the lock pin;
Comprising an unlocking mechanism comprising
It is characterized by that.
The fifth invention is specifically shown in the following first, second and third embodiments.
In the above description, “rear” represents the direction in which the latch portion falls, and “front” represents the opposite direction. The notation is in accordance with the movement of the fixing device, and is different from the usage in the following embodiments.
Further, in the above description, the “frame body”, that is, the machine frame is equipment for attaching other functional members of the present fixing device, and in this embodiment, the casing of the square box is adopted, but it is not limited to this aspect. Absent.
The state taken when the latch part receives no other urging force other than the urging means related to the latch part is referred to as a “steady state”.
Furthermore, the bottom surface of the safety work fence body for the person's hole has a predetermined installation position, and the upper surface of the main body of the person hole cover frame, the upper surface of the receiving shelf (receiving surface), and other appropriate positions can be taken. There is a “predetermined installation position” corresponding to them.
In the present invention,
1. An inclined surface is formed on the lower surface of the housing;
2. A roller is placed on the lower surface of the housing,
Is a technical matter that is adopted as appropriate.

(Function)
When the safety work fence body for the person's hole is installed on the person's hole cover frame and removed, the fixing device operates as follows.
In the installation of the safety work fence body for the person's hole, the fixing device is simultaneously installed so that the lower end surface of the safety work fence body is placed on the upper surface of the opened human hole cover frame or the upper surface of the receiving shelf. Insert it into the inner surface of the frame.
At this time, the latch portion of the fixing device receives a pressure from the inner peripheral surface of the receiving shelf of the manhole cover frame from a steady state and receives a pulling operation against its elastic action, thereby facilitating the inner periphery of the receiving shelf. To pass through. This pull-in operation is performed by the inclined surface of the lower surface of the housing or the roller disposed together with the roller, but does not prevent other measures from being taken. When the lower end surface of the safety work fence body reaches a predetermined installation position, the safety work fence body is detached from the inner peripheral surface of the receiving shelf, and the casing is extended to the lower surface of the receiving shelf. That is, the latch portion returns to a steady state, and is in an engaged state, that is, a locked state with a receiving shelf of the manhole cover frame.
Thereby, the safety work fence body for the person's hole is stably installed without coming out upward.
To remove the safety work fence body for the person's hole, operate the lock release mechanism of the fixing device, and when the lock release lever is tilted backward, the lock pin is inserted into the lock pin engagement hole with urging force, and the latch part is tilted Hold on. As a result, the latch portion is continuously retracted from the steady state against its elastic action, and the housing of the latch portion is disengaged from the shelf of the manhole cover frame. Then, when the person hole safety work fence body is pulled upward, the person hole safety work fence body is easily removed from the person hole cover frame.

(Sixth invention)
In the fifth aspect of the present invention, the lock pin retracting mechanism comprises:
1) A slider that is held by a holding frame and moves orthogonally to the axial movement of the lock pin.
2) A swing arm that swings about a center pin fixed to the frame body and that moves the slider forward and backward,
3) A pushing wheel that is rotatably supported at the lower end of the swing arm and whose front end protrudes forward from the housing of the latch portion;
4) a return spring portion for returning the swing arm to the original position;
The sixth aspect of the present invention is constituted by adopting the configuration comprising
In the above, “front” corresponds to the fifth invention.
In the above configuration, when the curvature of the manhole cover frame is taken into consideration for the pushing wheel, even if the front end of the pushing wheel and the front end of the latch portion housing are flush with each other, the pushing wheel operates. There is no change, and therefore substantially protrudes.

(Function)
The pull-back mechanism of the lock pin acts as follows when installing and removing the safety work fence for the human hole from the human hole cover frame.
When installing the safety work fence for the main hole, when the pull-back mechanism for the lock pin is in the activated state, the pushing wheel first receives the pressure from the inner peripheral surface of the receiving hole of the main hole cover frame and moves the swing arm. Pushing backward, the swing arm, slider, and lock pin are moved to remove the lock pin from the lock pin engagement hole. As a result, the latch portion returns to the steady state, and the latch portion thereafter receives a contact action with the receiving shelf of the manhole cover frame described above. When the lock pin pull-back mechanism is not in the operating state, the latch portion is in a steady state, and therefore it is not necessary to release the lock.
To remove the safety work fence body for the person's hole, operate the lock release mechanism of the fixing device, and when the lock release lever is tilted backward, the lock pin is inserted into the lock pin engagement hole with urging force, and the latch part is tilted Hold on. As a result, the latch part is continuously retracted from the steady state against its elastic action, and the latch part is disengaged from the shelf of the manhole cover frame. Then, when the person hole safety work fence body is pulled upward, the person hole safety work fence body is easily removed from the person hole cover frame. In this process, the pushing wheel receives a pressure from the inner peripheral surface of the socket of the manhole cover frame and pushes the swinging arm backward to move the swinging arm, the slider and the lock pin. Remove the pin from the lock pin engagement hole. As a result, the latch unit returns to the steady state.

According to the safety work fence body for manholes of the present invention, the safety work fence body for manholes is quickly and firmly and securely installed on the manhole cover frame by a simple operation. It is possible to ensure the safety of entering and exiting workers through the safety work fence body.
Moreover, also in the removal of the said safety work fence body for manholes, it removes rapidly by simple operation, and working efficiency improves.
In particular, since the fixing device for the safety work fence body for the person's hole has a release mechanism composed of the pushing wheel and the swinging arm, the safety work fence body for the person's hole can be used even if the fixing device remains in the unlocked state. At the time of insertion, the latch part automatically enters a steady state, and it is not necessary to place the latch part in a steady state.

The plane block diagram which shows the whole manhole cover frame with which the safety work fence body for manholes of this invention is mounted | worn. FIG. 5 is a partial cross-sectional front view showing the entirety of one embodiment of a safety work fence body for manholes installed on the manhole cover frame of the present invention (viewed in two directions in FIG. 3 and FIG. 4). The top view of this safety work fence body (3 direction arrow directional view of FIG. 2, FIG. 4). FIG. 4 is a side view of the safety work fence body (viewed in four directions in FIGS. 2 and 3). The front view which shows the whole of one Embodiment of the fixing device with which the safety work fence body for manholes of this invention is mounted | worn (5 direction arrow line view of FIG. 6). The top view of a fixing device (6 direction arrow line view of FIG. 5). The elements on larger scale of FIG. FIG. 8 is a cross-sectional view taken along line 8-8 in FIG. The whole block diagram of a lock release mechanism. FIG. 10 is a sectional view taken along line 10-10 in FIG. 9; FIG. 11 is an enlarged sectional view taken along line 11-11 in FIG. 10; 12-12 sectional view taken on the line of FIG. The partial part which shows other embodiment of the fixing device with which the safety work fence body for manholes of this invention is mounted | worn.

An embodiment of a safety work fence body for manholes having a fixing device for a lid frame of the present invention will be described based on the drawings.
(First embodiment)
Based on FIGS. 1-12, the safety work fence body S for manholes which has the fixing device to the cover frame of one Embodiment (1st Embodiment) is demonstrated.
That is, FIG. 1 shows a manhole cover frame M on which a manhole safety work fence body S having a fixing device for the main cover frame is installed, and FIGS. FIG. 5 to FIG. 12 show the portion and the detailed configuration.
A manhole safety work fence body (hereinafter simply referred to as “safe work fence body”) S having a fixing device for the lid frame is used by being attached to the opened manhole cover frame M. In the description of the safety work fence body S, the side where the worker enters and exits is the front part.

First, the human hole lid frame M on which the personal hole safety work fence S is installed will be described. The person's hole lid frame M is normally fitted with a predetermined iron lid F (not shown, only a symbol) and is in a lid state, but the iron lid F is outside the gist of the present invention. Is omitted.
Manhole cover frame M (See Figs. 1 and 2)
The personal hole cover frame M has a basic configuration in which an annular main body 100 and a bottom plate portion 102 that is horizontally stretched on the outer periphery of the lower end of the main body 100 are integrally formed of iron. On the outer surface of the main body 100, ribs 104 (made of iron) that are integral with the bottom plate portion 102 are provided with a gap therebetween. The upper surface 106 of the main body 100 is a smooth surface, and the inner peripheral surface of the main body 100 is formed with a tapered surface 108 that decreases in diameter as it goes downward, and a horizontal receiving surface 110 is formed following the tapered surface 108. A shelf 112 having an upper surface is projected, and a vertical lower wall surface 114 is formed below the shelf 112.
As shown in the figure, the thickness of the shelf 112 of the personal hole lid frame M is thin (small).
Reference numeral 120 denotes an iron lid shelf that is integrally projected at one location on the inner periphery of the human hole lid frame M (this location is the rear portion of the personal hole lid frame M). An insertion hole 122 is opened in the iron lid shelf 120.

The personal hole safety work fence body S is installed corresponding to the above-described human hole lid frame M.
Safety work fence S for human holes (See Figs. 2 to 4)
The person-hole safety work fence body S is composed of main parts of an upper fence body Sa and a fixing device Sb fixed below the fence body Sa.

Fence body Sa (see FIGS. 2-4)
The fence body Sa includes an annular bottom plate body 1 having a notch in a part thereof, an annular lower frame ridge 2 that is in phase with the bottom plate body 1 and fixed to the upper surface of the bottom plate body 1, A skeleton body is constituted by a column frame 3 erected from the lower frame frame 2, an upper frame frame 4, and an intermediate frame frame 5, and an upper frame part 6 that forms an entrance / exit space for an operator at the front part, and The front handle part 7 attached to the front part of the lower frame rod 2 is included. In addition, a pilot lamp mounting rod 8 standing on the rear end portion of the upper frame rod 4 of the upper frame portion 6 is added.

Hereinafter, the detailed structure of each part of the fence body Sa will be described.
Bottom plate 1 and lower frame 2
The bottom plate 1 is formed in a circular plate having a fixed thickness and a fixed width with a metal flat plate, and is placed on the receiving surface 110 of the shelf 112 of the manhole cover frame M. In the present embodiment, a notch 10 is formed at the rear end of the bottom plate 1, but the notch 10 can be omitted as appropriate.
On both sides of the inner diameter portion of the bottom plate body 1, there are provided mounting portions 12 for connection with the fixing device Sb. The mounting portion 12 has a shelf shape projecting in the inner diameter direction, and is formed with a screw hole 13 and a lever insertion recess 14.
The lower frame rod 2 is made of a light metal (for example, aluminum) hollow circular tube, has the same phase as the bottom plate 1 and is fixed to the upper surface of the bottom plate 1 by welding or the like.

Upper frame part 6
The upper frame portion 6 includes a column pole 3 standing upright at an angle from the lower frame pole 2, an upper frame pole 4 fixed to the upper end of the pole pole 3, and an intermediate frame arranged between the pole poles 3 It consists of 杆 5. The column rod 3, the upper frame rod 4 and the intermediate frame rod 5 are made of a light metal hollow circular tube like the lower frame rod 2, and form a fence structure as a whole, and the front portion forms an entrance / exit space for the operator.
(Post 3)
The pillar rod 3 is composed of a plurality of pieces, and is inclined to the inner diameter direction as it goes upward, and is erected on the lower frame rod 2 at a constant interval. The two pillar rods 3a at the front end portion are kept parallel. The diagonal column rod 3a at the front end also serves as a handle for the operator.
(Upper frame 4)
The upper frame rod 4 is fixedly installed at the upper end of the column rod 3 with its front portion largely opened for entry / exit of workers. That is, the upper frame rod 4 has a semicircular shape slightly exceeding a half circumference, and both end portions of the upper frame rod 4 are connected to the upper end of the column rod 3a at the front end.
Although the upper frame ridge 4 exceeds a semicircle in this embodiment, it does not preclude taking an aspect of a semicircle or less in some cases.
(Intermediate frame 杆 5)
The intermediate frame rod 5 is horizontally disposed between the column rods 3. The intermediate frame rod 5 functions as an operator's handle together with the upper frame rod 4.
(Upper frame part 6)
The lower frame rod 2, the column rod 3, the upper frame rod 4, and the intermediate frame rod 5 are not limited to the hollow circular pipes described above, but may be solid members or polygonal members, and the material is not limited to aluminum. Other metal materials (for example, stainless steel) are appropriately selected. In short, what is necessary is just to satisfy that the integral structure of the lower frame rod 2 and the column rod 3, the upper frame rod 4, and the intermediate frame rod 5 constitutes a strong structure.
In the present embodiment, the pillar rod 3 is inclined in the inner diameter direction and is reduced in diameter, but does not hinder the vertical installation.

(Skeleton)
A skeleton body of the safety work fence body S for the person's hole is constituted by the above-described bottom plate body 1, the lower frame rod 2, the column frame 3, the upper frame rod 4, and the intermediate frame rod 5. The skeleton body forms an integral structure and exhibits a large strength with rigidity.

Front handle 7
The front handle portion 6 has an inverted U shape and is attached to a lower position along the inner edge portion of the upper surface of the front portion of the lower frame rod 2. The horizontal portion has a curvature along the inner peripheral edge of the lower frame rod 2 and takes a height that does not hinder the entry and exit of the operator.
Pilot light mounting 杆 8
The pilot lamp mounting rod 8 is erected at the rear end portion of the upper frame rod 4 of the upper frame portion 6,
A pilot lamp (rotating lamp) is attached to the mounting rod 8. The pilot lamp mounting rod 8 is not limited to this aspect, and does not prevent the pilot lamp mounting rod 8 from being attached to the other side surface of the upper frame portion 6.

Fixing device Sb (see FIGS. 5 to 12)
The fixing device Sb adopts a configuration in which a latch mechanism is arranged in a casing, and is fixed to the attachment portion 12 of the bottom plate body 1 of the fence body Sa via the casing.
In the following description of the fixing device Sb, “front” is determined from the viewpoint from the outside to the center of the fence body Sa, and “left and right” is from the viewpoint above the inside of the fence body Sa, or by the operator. It is decided from the viewpoint of pushing down the unlock lever.
In the present embodiment, the fixing device Sb is
1) Square box-shaped casing 20 (front plate 20a, top plate 20b, bottom plate 20c, both side plates 20d, back plate 20e),
2) A plurality of latch portions of a latch portion A21, a latch portion B22, and a latch portion C23 disposed on the front surface of the casing 20,
3) An unlocking mechanism 24 that is interlocked with the latch portion and whose main portion is incorporated into the casing 20 and is manually operated.
Is the main component.

Hereinafter, the configuration of each part of the fixing device Sb will be described in detail.
Casing 20 (See FIGS. 5 to 8)
The casing 20 has a hollow rectangular box inside, and includes a front plate 20a, an upper plate 20b, a lower plate 20c, left and right side plates 20d, and a rear plate 20e. The front plate 20a, the upper plate 20b, the lower plate 20c, and the left and right side plates 20d are formed in an integrally open box shape and opened toward the back surface, and the back plate 20e is closed so that the open box body can be fitted and removed from the back surface. To do. In this assembly relationship, the back plate 20e, the top plate 20b, the bottom plate 20c, and the left and right side plates 20d may be integrated so that the front plate 20a can be fitted and removed. In addition, the casing 20 emphasizes a machine frame (frame) function for holding each mechanism mounted on the casing 20 with rigidity rather than hermeticity. The plate material can be omitted as appropriate or a part thereof can be deleted.
The front plate 20a is provided with a rectangular frame-like window portion 26 in which the latch portion A, the latch portion B, and the latch portion C are arranged. Further, window portions 27 and 28 are provided on the front plate 20a.
The upper surface plate 20b is provided with an elongate guide hole 30 for guiding the forward / backward movement of the unlocking lever of the unlocking portion 24, which will be described later, and is extended on both sides thereof. A plurality of screw insertion holes 31 corresponding to the screw holes 13 of the mounting portion 12 formed in the Sa bottom plate 1 are opened.
Therefore, the fixing device Sb is attached to the fence body Sa by aligning the guide hole 30 with the lever insertion recess 14 of the attachment portion 12 and aligning the screw insertion hole 31 with the screw hole 13 of the attachment portion 12. Fix with fasteners (screws) attached to the holes 31 and 12.

Latches A to C21, 22, 23 (see FIGS. 5 to 8)
Each latch part of the latch part A21, the latch part B22, and the latch part C23 is independently attached to the window part 26 of the front plate 20a of the casing 20, and adopts a partly common configuration and is specific to each function. The configuration of
Therefore, the latch part A21, the latch part B22, and the latch part C23 operate independently of each other and also operate in conjunction with each other.
The latch portion A21 is referred to as “center latch (or center latch)”, the latch portion B22 is referred to as “left latch (or left latch)”, and the latch portion C23 “right latch (or right latch)”.

(Latch part A21) (see FIGS. 7 and 8)
The latch part A (that is, the central latch) 21 is
1) Plate body 35A having a vertically long rectangular rigidity,
2) A housing 36A projecting forward from the upper end of the plate body 35A at a certain distance.
3) Roller portion 37A mainly composed of a roller 37a disposed in the lower portion of the housing 36A, 4) Elasticity (spring) between the lower end of the plate body 35A and the lower edge portion of the window portion 26 of the front plate 20a of the casing 20 Urging) elastic hinge 38A connected with action,
5) A concave portion 39A provided for the latch portion adjacent to the right,
6) A push rod 40A protruding from another latch portion adjacent to the left,
7) A casing 41A fixed to the upper end of the back surface of the plate body 35A,
It consists of each member.
More specifically, the plate body 35A has a certain thickness, maintains rigidity, and forms a rectangular plate that is long in the vertical direction. The upper edge of the plate body 35 </ b> A is disposed with a slight gap from the upper edge of the window portion 26. In order to increase the rigidity, it is a design consideration that reinforcing ribs (not shown) are appropriately formed on the back surface (or the front surface) of the plate body 35A.
The casing (or also referred to as a bowl-shaped member) 36A has rigidity and projects forward from the upper end of the plate body 35A with a certain distance. The casing 36A is a mass in which the upper surface 36a is a horizontal surface and the lower surface 36c is reduced in thickness obliquely downward via the front end surface 36b, but is not limited to this shape as long as it has rigidity. The front end face 36b is free to be appropriately rounded. The housing 36A is formed with a recess and a shaft hole in which a roller portion 37A described later is disposed.
The upper surface 36a of the housing 36A comes into contact with the lower surface of the shelf 112 of the human hole lid frame M.
The roller portion 37A includes a roller 37a and a shaft 37b penetrating through the center of the roller 37a, and is integrally incorporated in the recess and shaft hole of the housing 36A described above on the lower surface of the housing 36A. That is, the shaft 37b is strongly fitted in the shaft hole of the housing 36A so as not to rotate and is pivotally supported by the shaft hole, and the roller 37a is rotatable with respect to the shaft 37b.
Thus, the roller 37a has its circumferential side surface protruding from the inclined lower surface 36c of the housing 36A, slightly protruding from the front end surface 36b of the housing 36A, or substantially flush.

The elastic hinge 38A includes a pin shaft 38a, two blades 38b that rotate around the pin shaft 38a, and a spring body 38c that is disposed across the two blades 38b. The lower end of the plate 35A And the edge of the window portion 26 of the front plate 20a of the casing 20 are connected with an elastic (spring biasing) action. That is, the elastic hinge 38A abuts the blade 38b on the front surface of the plate body 35A and the front surface of the front plate 20a of the casing 20, and is fixed with the screws 43. The elastic hinge 38A rotates about its pin shaft 38a, but immediately returns to its original state after the rotation by the action of a spring body 38c interposed between the upper and lower blades 38b. The elastic hinge 38A is in a linear state (180 °) and is in a stopped state, and allows a backward fall, but prevents a forward fall. Thus, when the plate body 35A receives a force to tilt backward, the plate body 35A rotates around the pin shaft 38a of the elastic hinge 38A, and immediately returns to its original position when the force is removed. The elastic hinge 38A is a known one.
The recess 39A is recessed on the side surface of the plate body 35A corresponding to the adjacent latch portion, and abuts against the push rod 40 (in this case, 40C) protruding from the side surface of the adjacent latch portion.
The push rod 40A is fixed to the side surface of the plate A35 corresponding to the other adjacent latch portion, and protrudes across the side surface of the other adjacent latch portion. The push rod 40A in the present embodiment adopts a mode in which the push rod 40A is firmly inserted into a fixing hole drilled in the thickness of the lower surface 36c portion of the housing 36A, but is not limited to this, for example, on the side surface of the housing 36A. It may be fixed by welding.
The casing 41A has a rectangular parallelepiped rigidity, and is fixed to the upper end of the back surface of the plate body 35A. The distance between the back surface of the casing 41A and the back plate 20e of the casing 20 regulates the tilt angle of the plate body 35A with respect to the backward tilt. The housing 41A can be omitted as appropriate, and cavities and recesses are appropriately formed for weight reduction. Further, the casing 41A may be omitted except for the latch portion C, or may be a soft one.

(Latch part B22)
The latch portion B (that is, the left latch) 22 has substantially the same member configuration as the latch portion A, and includes plate member 35B, housing 36B, roller portion 37B, elastic hinge 38B, recess 39B, and housing 41B. But there is no push bar. Of these members, the positions of the housing 36B, the roller portion 37B, and the recess 39B are different from the latch portion A.
That is, the housing 36B is located above the housing 36A, and the difference in the height of the upper surface 36a corresponds to the difference in the thickness of the shelf 112 of the manhole cover frame M as will be described later. Therefore, the roller part 37B is also located above the roller part 37A. The position of the recess 39B corresponds to the position of the push rod 40A of the latch part A and takes the same horizontal position.
The latch portion B22 performs substantially the same operation and operation as the latch portion A21.

(Latch part C23)
The latch part C (that is, the right latch) 23 has members of a plate body 35C, an elastic hinge 38C, a push rod 40C, and a housing 41C, and does not have a roller portion, a housing, and a recess. That is, the surface of the latch portion C23 is substantially flat without any protrusions other than the push rod 40C.
More specifically, in this latch portion C23, the push rod 40C is disposed at a position corresponding to the concave portion 39A of the adjacent latch portion, but its attachment is directly fixed to the surface of the plate body 35C. Further, the casing 41C maintains rigidity, its right side surface holds a smooth surface, and a circular recess or recess is formed in the front portion of the right side surface.
Thus, the latch portion C is interlocked with other latch portions and is also interlocked with a latch release mechanism. For this reason, in the latch portion C, a latch release lever is fixedly provided on the upper surface of the casing 41C in addition to the side surface portion and the concave portion.

(Operation of latches A, B, C)
The latch portions A, B, and C are independent and interlocked with each other according to the operation.
That is, when the latch part C tilts backward from the steady position of the latch part, the push rod 40C of the latch part C tilts the latch part A backward via the recess 39A of the latch part A, and further the latch part A tilts the latch portion B backward via the push rod 40A.
Since the latch portions A, B, and C are independent of each other, the return to the front of the latch portion C leaves the latch portion A (and therefore the latch portion B) and returns to the original position. Similarly, when the latch portion A is returned to the front, the latch portion B remains and returns to the original position.

Unlocking mechanism 24 (see FIGS. 9 to 7 and 9 to 12)
The lock release mechanism 24 is interlocked with the latch portion, and most of the mechanism is incorporated in the casing 20 and is operated with a manual lever and a pushing wheel outside the casing 20.
In this embodiment, the lock release mechanism 24 is
1) A lock release lever 50 and a lock pin engaging hole 51 arranged in the latch portion C23,
2) a holding frame 54 for holding the lock pin 52 and the slider 53;
3) A swing arm 56 that swings about the center pin 55 as the center of rotation and moves the slider 52 forward and backward.
4) a pushing wheel 57 rotatably supported at the lower end of the swing arm 56;
5) A return spring portion 58 for returning the swing arm 56 to the original position;
including.

(Lock release lever 50 / lock pin engagement hole 51)
On the upper surface of the latch portion C23, a lock release lever 50 comprising a lever bar 50a and a grip portion 50b is fixed. The movement of the lock release lever bar 50a is guided in the guide groove 30 of the upper surface plate 20b of the casing 20.
As described above, the upper portion of the latch portion C23 has the flange portion 41C that maintains a constant thickness, the right side surface thereof is a smooth surface, and the lock pin engagement hole 51 is recessed near the front surface.
When the lock release lever 50 is pushed, the latch portion C23 falls backward with the elastic hinge 38C as the center.

(Lock pin 52, slider 53, holding frame 54)
The holding frame 54 has a substantially square box shape, has a function of holding the lock pin 52, the slider 53, and other functional members, and is fixed to the upper portion of the casing 20 (that is, corresponding to the upper position of the latch portion C23). Is done.
The length of the holding frame 54 is equal to the inner width of the casing 20, and the ceiling plate 54a and the bottom plate 54b are held at a constant height by the rear wall plate 54c, the side wall plate 54d, and the partition plate 54e. The frame 54 retains rigidity as a whole. As will be described later, the holding frame 54 has insertion holes 54f and 54g for the lock pin 52 in the side wall plate 54d and the partition plate 54e, and a long hole 54h for guiding the lock pin 52 in the ceiling plate 54a. Further, a long hole 54i for guiding the slider 53 is opened in the bottom plate 54b.
The lock pin 52 includes a round bar-like pin body 52a, a round bar-like vertical bar 52b at the end (rear end) of the pin body 52a, and a hook-like reaction force fixed to the front side of the pin body 52a. And a receiver 52c. A coil spring 52c is also included.
The round rod-shaped pin body 52a is inserted into the side wall plate 54d of the holding frame 54 and the pin holding holes 54f and 54g provided in the partition plate 54e, and a coil spring 52c is provided between the reaction force receiver 52c and the partition plate 54e. Installed. Thus, the lock pin 52 is movable in the axial direction of the pin main body 52a and receives a biasing force toward the front in the axial direction of the pin main body 52a. The front end surface is in contact with the wall surface of the latch portion C23.
The vertical bar 52b at the rear end of the pin body 52a has a predetermined relationship with the following slider 53 to give the 52 a predetermined operation.
The slider 53 has a single rectangular parallelepiped shape. The upper and lower surfaces of the slider 53 are slidably sandwiched between the ceiling plate 54a and the bottom plate 54b of the holding frame 54, and the slide 53 receives the pin main body 52a of the lock pin 52 therein. A hole 53a is opened.
One side (right side surface) of the rectangular parallelepiped is notched to form an inclined surface 53b.
The vertical bar 52 b of the lock pin 52 is longer than the height of the slider 53, and the upper part thereof is fitted into a guide long hole 54 i formed in the ceiling plate 54 a of the holding frame 54.
Regarding the relationship between the lock pin 52, the slider 53, and the holding frame 54, the lock pin 52 is pressed toward the latch portion C in response to the urging force of the coil spring 52c in a steady state. The contact with the side wall surface of the part C is prevented from moving. When the latch portion C moves and the lock pin engagement hole 51 comes to the position of the lock pin 52, the lock pin 52 is displaced and enters the lock pin engagement hole 51. Thereby, it will be in a locked state. At this time, the vertical bar 52 b of the lock pin 52 is displaced forward from the initial position to a position where it abuts against the side surface of the slider 53. There is no movement of the slider 53.
When the slider 53 is pulled in with a forcible force, the vertical bar 52b of the lock pin 52 receives a component force from the inclined surface 53b due to contact with the inclined surface 53b of the slider 53, and moves backward in the right direction. Accordingly, the lock pin 52 moves backward against the urging force of the coil spring 52c. Thereby, the lock pin 52 comes off from the lock pin engagement hole 51 and returns to the steady state.

(Swinging arm 56) (see FIGS. 9 and 10)
The swing arm 56 swings around the center pin 55 as a rotation fulcrum and functions to move the slider 52 forward and backward.
The swing arm 56 is a long flat plate and occupies a large portion of the internal space of the casing 20 below the holding frame 54. A pin body 56a protrudes from the upper end of the pin body. An insertion hole for the pin body is formed at the lower side and the lower end part, and a protrusion 56b is fixed to the intermediate part.
The center pin 55 is attached via a pillar member 60 fixed to the right side plate 20d of the casing 20. Since the center pin 55 is attached to the lower side of the swing arm 56, the upper end of the swing arm 56 is displaced more greatly than the movement of the lower end of the swing arm 56.
In the upper part of the swing arm 56, the pin body 56 a is fitted into a recess 61 a formed on the lower surface of the rectangular parallelepiped thrust body 61 fixed to the lower surface of the slider 53.
The thrust body 61 is fitted into a long guide hole 54i provided in the bottom plate 54b of the holding frame 54, and the longitudinal movement is guided through the long hole 54i. Further, the pin body 56 a is fitted into the recess 61 a of the thrust body 61 with a variation (gap) in the height direction accompanying the swing of the swing arm 56.

(Push-in wheel 57 / return spring 58)
The pushing wheel 57 is rotatably supported at the lower end of the swing arm 56, and a part of the pushing wheel 57 projects outside the casing 20 through the window portion 27 of the casing 20. That is, the central shaft body of the pushing wheel 57 is rotatably supported through the rotation shaft hole of the swing arm 56 to rotate the main body of the pushing wheel 57. The pushing wheel 57 receives a pushing force from the outside and transmits the force to the swing arm 56.
The return spring portion 58 is fixed to the lower surface of the bottom plate 54b of the holding frame 54, and includes a reaction force bar 58a that maintains rigidity to be hung downward, and the reaction force rod 58 and the protrusion 56b of the swing arm 56 described above. The main body is a tension spring 58b interposed therebetween. The return spring portion 58 does not substantially exert a force in the steady position, and exerts a pulling action when the swing arm 56 is separated, thereby returning the swing arm 56 to the original position.
When the pushing force acts on the pushing wheel 57 in the pushing direction, the swing arm 56 moves the upper part (pin body 56a) around the center pin 55 as the center of rotation in the direction opposite to the pushing direction (the drawing direction), and the thrust body 61. (Slider 53) is pulled in the retracting direction. As the upper portion of the swing arm 56 is displaced in the retracting direction, the tension spring 58b of the return spring portion 58 exerts a tension biasing action, and the swing arm 56 is returned to the original position by the pull back force.

(Operation of this embodiment)
The safety work fence body S for manholes having the above-described configuration is installed facing the opening of the opened manhole, and the worker enters and exits the manholes through the installed safety work fence body S. To do.
And in this installation work, the safety work fence body S for the person's hole can be installed quickly and reliably by the fixing device Sb, and the removal safety and speed can be achieved.

A. Installation of the safety work fence body S for the principal hole Hereinafter, the installation work of the safety work fence body S for the principal hole will be described in the order of the steps.
In this embodiment, the case where the shelf 112 of the manhole cover frame M is thin will be described.
(1)
When the safety work fence S for the person's hole is installed, the iron cover F (not shown) of the person's hole is opened. The swing arm of the iron cover F is loosely inserted into the insertion hole 122 of the iron cover shelf 120 of the human hole cover frame M, and after the iron cover F is lifted, the swing arm of the iron cover F is inserted. Is rotated 180 ° horizontally around the center of rotation.
In addition, as for the fixing device Sb of the safety work fence body S for the person's hole, the unlocking lever 50 is locked to maintain the operating state, that is, the state where all the latch portions A, B, C are retracted (unsteady state). It is in the state.

(2)
The operator holds an appropriate position (usually the upper frame ridge 4) of the fence body Sa of the safety work fence body S for the person's hole, and the person hole cover frame M in which the bottom plate body 1 of the safety work fence body S is opened. The person's hole safety work fence body S is inserted into the person hole cover frame M so as to be placed on the receiving surface 110 of the shelf portion 112 of the person. The rear part of the safety work fence body S, that is, the rear part of the bottom plate body 1 and the lower frame rod 2 has a notch 10, and the notch 10 is installed across the swing arm of the iron lid F.
With respect to the safety work fence S for the person's hole, the initial state of the fixing device Sb can be used in both states regardless of whether the unlocking lever 50 is activated or deactivated. It is assumed that it is in a state (that is, the lock release lever 50 is in a collapsed state).
Then, the two opposing fixing devices Sb are inserted into the inner diameter of the shelf 112 of the human hole lid frame M.

(3)
When the pushing wheel 57 of the fixing device Sb comes into contact with the inner peripheral surface of the shelf portion 112 of the manhole cover frame M and the pushing wheel 57 receives the pushing force, the unlocking mechanism 24 is activated and the lock pin 52 is latched. All the latch portions A, B, and C are in a steady state by being disengaged from the lock pin engaging hole 51 of the portion C23.
(3-1)
The operation of the lock release mechanism 24 by the pushing wheel 57 will be described.
When the pushing wheel 57 receives the pushing force, the lower part of the swing arm 56 moves forward (in the direction of the center of the human hole), and the swing arm 56 has an upper part (pin body 56a) with the center pin 55 as the center of rotation. Moves rearward and draws the thrust body 61 and the slider 53 rearward.
When the slider 53 is pulled rearward, the vertical bar 52b of the lock pin 52 moves to the right by receiving a component force from the inclined surface 53b due to contact with the inclined surface 53b of the slider 53, and locks. The pin 52 moves backward against the biasing force of the coil spring 52c. As a result, the lock pin 52 is disengaged from the lock pin engagement hole 51, and the lock pin 52 returns to the steady state (open state).
When the lock pin 52 is disengaged from the lock pin engaging hole 51 of the latch portion C, the latch portion C restrained by the lock pin 52 returns to the original position by the restoring force of the elastic hinge 38C, and each latch portion A The latch portions B are also independently returned to their original positions by the restoring force of their elastic hinges 38A, B. As a result, the latch portion takes a steady state.
(3-2)
When the pushing wheel 57 is lowered in this state, the pushing wheel 57 is detached from the inner peripheral surface of the shelf portion 112 of the manhole cover frame M and released from the pushing force when reaching the lower wall surface 114 of the manhole cover frame M, and the swing arm 56 is returned. The spring portion 58 returns to the original position by the pulling back force of the tension spring 58b. As a result, the swing arm 56, the pushing wheel 57, the thrust body 61, and the slider 53 are restored to the steady state.

(Four)
When the fixing device Sb is further lowered and the latch portion reaches the shelf portion 112 of the manhole cover frame M, first, the latch portion C23 has no particular protrusion and passes through the inner peripheral surface of the shelf portion 112 without resistance. Then, after the latch portion A21 contacts the inner edge of the shelf portion 112 of the manhole cover frame M in the order of the roller portion 37A and the housing 36A, the latch portion A21 contacts the inner peripheral surface of the shelf portion 112 of the manhole cover frame M. It is pressed against and receives a pressing force from the inner peripheral surface. At this time, the roller 37a of the roller portion 37A facilitates the insertion operation of the latch portion A21.
Thereby, the latch part A21 falls forward (back part), and the adjacent latch part B22 is also linked forward by the push rod 40A.

(Five)
In this state, when the fixing device Sb continues to descend and the latch part A descends, the latch part A comes off the inner peripheral surface of the shelf 112 of the manhole cover frame M and returns to the steady state. B continues to the shelf 112 of the manhole cover frame M, receives a pressing action from the inner peripheral surface of the shelf 112, and falls into a collapsed state.

(6)
When the fixing device Sb is further lowered and the bottom surface of the fence main body Sa of the safety work fence body S for the main hole approaches the receiving surface 110 of the shelf portion 112 of the human hole cover frame M, it is latched immediately before that. The part B comes off from the inner peripheral surface of the shelf 112 of the manhole cover frame M, and the housing 36B enters the lower surface portion of the shelf 112.
As a result, the main fixing device Sb is engaged with the shelf 112 of the manhole cover frame M with the housing 36B of the latch portion B, and is stably installed against the pulling force of the safety work fence body S for the manhole. Take a state.

(7)
With the above, the installation work of the safety work fence body S for the principal hole is completed.
During the above process, when the unlocking lever 50 is not in operation and the latch portion is in the steady state in the process (1), the pushing wheel 57 receives the pushing force in the process (3), and the unlocking mechanism Even if 24 operates, there is no effect on the latch part C, and the latch part maintains a steady state. Thereafter, the steps after step (4) are taken.
And all the installation processes during this time are made quickly, and it is installed without requiring a special pushing force in combination with the dead weight of the safety work fence body S for the principal hole.

After entering / exiting the worker's hole, the worker enters / exits the hole from the front of the safety work fence S for the person's hole.
In the hole, the operator enters from the front part of the safety work fence body S, and appropriately holds the upper work frame 4, the intermediate frame work 5, and the front handle part 7 while holding the upper work work fence S. The inside of the human hole is lowered through the footrest in the hole.
In the exit hole, when the worker ascends the inside of the human hole via the footrest in the human hole and reaches the opening of the human hole, the front handle portion 7 of the safety work fence body S and the intermediate frame rod are appropriately disposed. 5. While holding the upper frame rod 4, a hole is made from the front portion of the safety work fence body S. At this time, the front handle portion 7 of the safety work fence body S is lowered and does not become an obstacle to the exit hole.

B. Removal of the safety work fence S for the person's hole
(1)
The lock release lever 50 of the fixing device Sb attached to the safety work fence body S for the person's hole is tilted forward (toward the center of the person's hole), and all the latch portions A, B, C are held in a tilted state. The housing 36B of the part B is drawn from the shelf 112 of the manhole cover frame M to be in a pullable state.
That is, when the lock release lever 50 is tilted forward and the latch portion C is tilted forward, the latch portions A, B, C are interlocked via the push rods 40C, 40A. As a result, the latch portion B is It becomes a state.
On the other hand, when the lock release lever 50 is tilted forward, the tip of the lock pin 52 slides on the side wall surface of the latch portion C, and when the lock pin 52 reaches the lock pin engagement hole 51, the lock pin 52 is attached in the axial direction. The lock pin engagement hole 51 enters with force. At this time, the lock pin 52 moves to the left, but the vertical bar 52b of the lock pin 52 comes into contact with the side surface of the slider 53 and stops. Or it stops when the reaction force receiving 52c of the lock pin 52 contacts the side wall plate 54d.
As a result, the latch portion C thereafter maintains the collapsed state.

(2)
The operator holds an appropriate position (usually the upper frame rod 4) of the fence body Sa of the safety work fence body S for the personal hole, and pulls the fixing device Sb from the shelf 112 of the human hole cover frame M so as to pull out the main hole. The safety work fence body S is pulled upward.
At this time, all the latch portions A, B, and C of the fixing device Sb are in the retracted state, and easily pass through the inner peripheral surface of the shelf portion 112 of the manhole cover frame M. Then, at least the housing 36A of the lowermost latch portion B comes out of the shelf portion 112.

(3)
In this state, when the pushing wheel 57 reaches the shelf 112 of the manhole cover frame M, the pushing wheel 57 comes into contact with the inner peripheral surface of the shelf 112 of the manhole cover frame M, and the pushing wheel 57 pushes the pushing force. Receive. As a result, the lock release mechanism 24 is activated, the lock pin 52 is disengaged from the lock pin engaging hole 51 of the latch portion C, and all the latch portions A, B, C of the latch portion are in a steady state.
(3-1)
When the pushing wheel 57 passes from the inner peripheral surface of the shelf portion 112 of the manhole cover frame M without receiving any particular pressing force, the lock release mechanism 24 does not operate, but the personhole safety work fence S There is no hindrance to pulling upward.

(Four)
The pushing wheel 57 rolls on the inner peripheral surface of the shelf 112 of the manhole cover frame M and comes out above the shelf 112.
Thus, the removal work of the safety work fence body S for the person hole is completed.
In addition, all the removal processes during this time are made quickly, and the weight of the safety work fence body S for the person's hole is light and can be easily removed without requiring any special lifting force.

(Effect of this embodiment)
According to the safety work fence body S for manholes of the present embodiment, the safety work fence body S for manholes S can be quickly and easily installed on the manhole cover frame M via the fixing device Sb. Installed securely.
That is, by the operation of the fixing device Sb, the housing of the latch portion is engaged with the shelf portion 112 of the manhole cover frame M, so that the fixing force is opposed and the fixing is reliably performed.
In addition, it is possible to secure the speed and safety of entry and exit of the worker through the manhole safety work fence body S after installation, and the installation of the manhole safety work fence body S allows traffic during construction. Human safety is ensured, and the pilot light is attached to the pilot light mounting rod 10 so that a passerby can pay attention, thereby further increasing safety.
Moreover, also in the removal of the said safety work fence body S for manholes, it removes rapidly by simple operation, and working efficiency improves.
In particular, the fixing device Sb of the safety work fence body S for manholes according to the present embodiment has the release mechanism 24 having the pushing wheel 57 and the swing arm 56, so that the fixing device Sb remains in the unlocked state. However, when the safety work fence body S for the person's hole is inserted, the latch part is automatically in a steady state, and it is not necessary to set the latch part in a steady state in advance, which saves time and ease of use.

(Another aspect)
C. In the above-described form of the safety work fence body S for the personal hole, the installation / removal work when the shelf 112 of the human hole cover frame M is thin is described. However, the installation / removal work when the shelf 112 is thick. Is as follows.
The steps (1) to (4) of A are the same in this embodiment C.

(Five)
In this state, when the fixing device Sb is lowered and the latch portion A is lowered, the latch portion A continues to be pressed against the inner peripheral surface of the shelf portion 112 of the manhole cover frame M, and the latch portion B continues to be the manhole. Although it reaches the shelf 112 of the lid frame M, the latch B continues to fall down due to the action of the push rod 40A of the latch A.

(6)
When the fixing device Sb is further lowered and the bottom surface of the fence main body Sa of the safety work fence body S for the main hole approaches the receiving surface 110 of the shelf portion 112 of the human hole cover frame M, it is latched immediately before that. The part A is disengaged from the inner peripheral surface of the shelf 112 of the manhole cover frame M, and the flange 36A enters the lower surface portion of the shelf 112.
As a result, the fixing device Sb is engaged with the shelf 112 of the manhole cover frame M with the flange 36A of the latch portion A, and resists the extraction force of the safety work fence body S for the manhole, and is stably installed. Take.

(7)
In the same manner as in (7) of A, the installation work of the safety work fence body S for the principal hole is completed.
Thus, according to the present embodiment, it is possible to cope with the case where the shelf 112 of the human hole lid frame M is thick, and it is possible to deal with various differences in the standard of the human hole lid frame M.

Second Embodiment (See FIG. 13)
In the first embodiment described above, the safety work fence S for manholes is installed on the upper surface of the shelf 112 of the manhole frame M, but in this embodiment (second embodiment) The mode in which the safety work fence body S for manholes is installed in the upper surface 106 of the manhole frame M is shown.
In the second embodiment, as shown in FIG. 13, the outer diameter of the bottom plate body 1 on the bottom surface of the fence body Sa of the safety work fence body S for human holes is at least larger than the inner diameter of the upper surface 106 of the human hole frame M. The inner diameter is approximately the same as the inner diameter of the shelf 112 of the human hole frame M. On both sides of the inner diameter portion of the bottom plate body 1, there are provided mounting portions 12 having a shelf shape projecting in the inner diameter direction for connection to the fixing device Sb, and screw holes 13 and lever insertion recesses 14 are opened in the mounting portion 12. This is the same as in the previous embodiment.
For the fixing device Sb, the position of the housing 36A of the latch portion B22 is determined by the distance H between the upper surface of the shelf 112 and the lower surface of the shelf 112 in the previous embodiment. The vertical distance from the upper surface 106 of the body M to the lower surface of the shelf 112 is determined.
The front surface of the casing 20 has a certain clearance from the inner diameter of the shelf 112 of the human hole frame M, has other configurations, for example, has three latch portions A, B, C, and has a lock release mechanism 24. , Etc. are not substantially different from the previous embodiment.
In the safety work fence body S for manholes of the second embodiment, the thickness corresponds to the thickness of the shelf 112 of the manhole frame M, as in the first embodiment.

(Third embodiment)
In the previous first and second embodiments, the latch unit has three latch units A, B, and C. However, in this embodiment (third embodiment), the configuration of the latch unit is different. Here, it is based on the change of the fixing device Sb of the first embodiment.
That is, in this embodiment, the latch part B is omitted and the width of the latch part C is narrowed.
Correspondingly, the mounting height of the housing 36A of the latch portion A is appropriately changed with respect to the thickness of the shelf 112 of the specific human hole frame M.
Further, the latch portion C is made as narrow as possible while ensuring a necessary width.
As a result, the width of the fixing device Sb for the safety work fence body S for the person's hole becomes small, and the work for inserting the safety work fence body S for the person's hole into the person hole frame M becomes easy. Usability of the body S is improved.

The present invention is not limited to the above embodiment, and various design changes can be made within the scope of the basic technical idea of the present invention. That is, the following technical matters are included in the technical scope of the present invention.
1. The lock release mechanism 24 of the present embodiment includes a pushing wheel 57, a swing arm 56, and a slider 53. However, the lock release mechanism 24 does not have such a mechanism, and at least the forward urging of the lock pin 52 and the lock pin 52. What is necessary is just to provide the mechanism which makes pull-back (retreat) after moving forward.
For this reason, the lock pin 52 is held by the holding frame 54 and is provided with the urging means 52d so as to be capable of moving forward and backward, as in the previous embodiment. A rigid operating rod (not shown) penetrating through 20e is fixed, and the operating rod is guided and held in a horizontal guide slot (not shown) formed in the back plate 20e of the casing 20, It is possible to adopt a structure in which the lock pin 52 that has advanced by grasping the projecting end of the operating rod to the outside of the casing 20 is pulled back. The projecting end of the operating rod to the outside of the casing 20 may be further extended upward. Alternatively, a wire (not shown) is connected to the rear end of the lock pin 52, and the wire is guided to the outside of the upper portion of the casing 20 via a pulley (not shown) arranged in the casing 20, and the tip of the wire is connected to the rear end of the lock pin 52. It is another means to adopt a structure for pulling back the lock pin 52 that has been gripped and advanced.

S ... Safety work fence for manhole, Sa ... fence body, Sb ... fixing device, M ... manhole cover frame,
106 ... upper surface, 110 ... receiving surface, 112 ... shelf part,
DESCRIPTION OF SYMBOLS 1 ... Bottom plate body, 2 ... Lower frame collar, 3 ... Pillar collar, 4 ... Upper frame collar, 5 ... Upper frame part,
20 ... casing, 20a ... front plate,
21 ... Latch part A, 22 ... Latch part B, 23 ... Latch part C,
24 ... Unlocking device, 26 ... Window,
35A, B, C ... plate body, 36A, B ... bowl-shaped member, 38A, B, C ... elastic hinge,
DESCRIPTION OF SYMBOLS 50 ... Lock release lever, 51 ... Lock pin engaging hole, 52 ... Lock pin, 53 ... Slider, 54 ... Holding frame, 55 ... Center pin, 56 ... Swing arm, 57 ... Pushing wheel, 58 ... Return spring Part

Claims (7)

A fixing device is attached to one or a plurality of places at the lower end of the safety work fence for manhole installed on the opened manhole cover frame,
The fixing device is
A frame body that retains rigidity and has a smaller diameter than the inner diameter of the shelf of the installed manhole cover frame is fixed to the lower end of the manhole safety work fence body,
It is attached via the frame body, receives an elastic action, has a diameter larger than the inner diameter of the receiving hole of the manhole cover frame in which the bowl-shaped member is installed in a steady state, and can be engaged with the receiving rack A latch member that takes a state;
When the latch member is inserted into the manhole cover frame to be installed, the latch member receives a pressing force from the inner peripheral surface of the receiving shelf of the manhole cover frame and receives a pull-in operation against its elastic action. When the installation position is reached, the hook-shaped member is detached from the inner peripheral surface of the receiving shelf and performs an overhanging operation on the lower surface of the receiving shelf.
A safety work fence for manholes having a fixing device.   A plurality of latch members are arranged side by side, each latch member has one hook-like member having a different height, and a latch member having a low-height hook-like member has a high hook-like member. A safety work fence body for a manhole having the fixing device according to claim 1, wherein only the backward movement is restricted.   A lock release mechanism for continuously releasing the engageable state in which the hook-like member of the latch member is retracted from the inner peripheral surface of the receiving shelf of the manhole cover frame against the elastic action in a steady state; A safety work fence body for manholes having the fixing device according to claim 1. A fixing device attached to the lower end of the safety work fence for manholes installed in the opened manhole cover frame,
A frame body that retains rigidity and has a smaller diameter than the inner diameter of the shelf of the installed manhole cover frame is fixed to the lower end of the manhole safety work fence body,
It is attached via the frame body, receives an elastic action, has a diameter larger than the inner diameter of the receiving hole of the manhole cover frame in which the bowl-shaped member is installed in a steady state, and can be engaged with the receiving rack A latch member that takes a state;
When the latch member is inserted into the manhole cover frame to be installed, the latch member receives a pressing force from the inner peripheral surface of the receiving shelf of the manhole cover frame and receives a pull-in operation against its elastic action. When the installation position is reached, the hook-shaped member is detached from the inner peripheral surface of the receiving shelf and performs an overhanging operation on the lower surface of the receiving shelf.
A device for fixing a safety work fence body for a human hole characterized by that. A fixing device attached to the lower end of the safety work fence for manholes installed in the opened manhole cover frame,
1) The upper part is fixed to the safety work fence body for manholes, has at least a flat front plate, and includes a frame body in which a rectangular window is opened on the front plate,
2) A plate body that fits into the window portion of the frame body is arranged so as to be able to elastically recover against a backward fall through an elastic hinge fixed to the lower edge of the window portion, and the plate body 1 or a plurality of latch portions in which a housing projecting forward is fixed to the front surface of
3) In the latch portion at the end, a lock release lever is erected on the upper surface, and a lock pin engagement hole is opened on the side end surface,
4) Arranged side by side with the latch part,
a) only a movement in the axial direction is allowed, and a lock pin fitted into the lock pin engagement hole with a biasing force in response to a predetermined tilting movement to the rear of the latch part;
b) a holding frame attached to the frame body and holding the lock pin;
c) A lock pin pull back mechanism that pulls back the lock pin in conjunction with the lock pin;
Comprising an unlocking mechanism comprising
A device for fixing a safety work fence body for a human hole characterized by that.   6. The fixing device for a safety work fence body for manhole according to claim 5, wherein a push rod that restrains only backward movement relative to other adjacent latch portions is arranged between the two or more latch portions. The lock pin pull back mechanism
1) A slider that is held by a holding frame and moves orthogonally to the axial movement of the lock pin.
2) A swing arm that swings about a center pin fixed to the frame body and that moves the slider forward and backward,
3) A pushing wheel that is rotatably supported at the lower end of the swing arm and whose front end protrudes forward from the housing of the latch portion;
4) a return spring portion for returning the swing arm to the original position;
The fixing device of the safety work fence body for manholes of Claim 5 provided with these.

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