JP2003313891A - Fall preventing apparatus for manhole - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new fall preventing apparatus for a manhole capable of effectively preventing the fall of tools with excellent mechanical strength, easily recycled and moreover prevented from being corroded in a short period. <P>SOLUTION: This fall preventing apparatus 10 for the manhole almost horizontally supported in an erectable manner to a receiving frame 2 below a manhole cover 1, is provided with a grid member 11 supported to the receiving frame 2; arm parts 12, 13 formed on both lateral sides of one side of the grid member and inserted through lateral openings formed inside the receiving frame 2, when erecting the grid member 11; locking members 15, 16 for locking the state of the grid member 11 being almost horizontally supported to the receiving frame 2; and a release member 19 for releasing the locked state by the locking members 15, 16. The grid member 11 is formed of cast iron and covers almost the whole inside opening of the receiving frame 2. <P>COPYRIGHT: (C)2004,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manhole cover supported by a receiving frame to prevent a worker from accidentally dropping into a manhole and to raise the manhole. The present invention relates to a fall prevention device for manholes, which is also used for a hook portion and a foot portion during work. 2. Description of the Related Art There has been proposed and implemented a manhole fall prevention device which is supported by a receiving frame of a manhole cover and prevents a worker from accidentally falling into a manhole. For example, the fall prevention device 100 for manholes disclosed in Japanese Patent Application Laid-Open No. 2002-38504 prevents a worker from accidentally falling into a manhole and raises a handhold or a footrest during work by standing up. 6 and 7, a ladder member 102 horizontally supported by a cylindrical receiving frame 101 supporting a manhole cover, and a ladder member 102 formed at a base end of the ladder member 102. And a hook portion 10 rotatably engaged with engagement shafts 103 and 104 formed on the receiving frame 101.
5, 106, formed at the tip of the ladder member 102,
Engagement projections 107, 10 formed on the inner peripheral surface of receiving frame 101
8 and the engaging members 109 and 110 that engage with the second member 8. As shown in FIG. 6, the ladder member 102 has left and right vertical bar members 111 and 112, and one end is fixed to the left vertical bar member 111 and the other end is the vertical bar member 112.
. And 117 are fixed to and are parallel to each other. Note that, outside the left and right vertical bar members 111 and 112, U-shaped bulging members 118 and 119 are formed, respectively. [0003] According to the conventional manhole fall prevention device 100, the ladder member 102 is provided with the ladder member 102 shown in FIGS.
As shown in the figure, in the state of being supported substantially horizontally, the worker working on the ground is prevented from falling into the manhole by mistake, and the ladder member 102 is erected to raise the inside of the manhole. When entering, it is possible to use it by hanging hands or feet. However, according to the above-described conventional manhole fall prevention device 100, since the ladder member 102 is formed in a ladder shape from stainless steel, it is large from above. When a load is applied, it is easily deformed and does not have sufficient mechanical strength, and from the viewpoint of preventing tools and tools used by an operator from falling, the inside of the receiving frame 101 is reduced. Is not enough to cover the opening. Further, the manhole cover and the receiving frame 101 on which the conventional manhole drop device 100 is supported are made of cast iron, but the main component of the conventional manhole drop device 100 is the main component of the ladder member 102. Since it is stainless steel as described above, it cannot be recycled like the receiving frame 101, and since the potentials are different from each other,
It also causes the corrosion of the receiving frame 101 and the manhole cover. Accordingly, the present invention has been proposed to solve the problems of the above-described conventional manhole fall prevention device, and has excellent mechanical strength and can effectively prevent a tool or tool from falling. It is another object of the present invention to provide a new manhole fall prevention device that can be easily recycled and can prevent corrosion in a short time. SUMMARY OF THE INVENTION The present invention has been proposed to solve the above-mentioned problems, and is substantially horizontally supported by a receiving frame below a manhole cover and can be raised. Manhole fall prevention device,
A lattice member supported by the receiving frame, and arms formed on left and right sides of one side of the lattice member, and inserted into left and right openings formed inside the receiving frame when the lattice member is raised. And a lock member for locking a state in which the lattice member is supported substantially horizontally by the receiving frame, and a release member for releasing a lock state by the lock member, wherein the lattice member is formed of cast iron. In addition, it covers substantially the entire opening inside the receiving frame. According to the present invention, since the grid member covers substantially the entire opening inside the receiving frame, it is possible not only to prevent an operator from accidentally falling into the manhole, but also to use a tool. It is also possible to prevent a tool or a tool from dropping into the manhole. The lattice member is made of cast iron. Since this material is the same material as the manhole cover and the receiving frame, it can be easily recycled, and has the same potential as that of the manhole cover and the receiving frame. Therefore, the progress of corrosion can also be suppressed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a fall prevention device for a manhole according to an embodiment of the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, a fall prevention device 10 for a manhole according to this embodiment (hereinafter referred to as the present device) is provided below a manhole cover 1 in a receiving frame 2 for supporting the manhole cover 1. It is supported horizontally,
The grid member 11 includes a first arm portion 12 formed on the left side of one side of the grid member 11, and a second arm portion 13 formed on the right side of one side of the grid member 11. . As shown in FIG. 1, the receiving frame 2 is formed into a substantially cylindrical shape and supports a manhole cover 1 on the inner periphery on the upper end side, and a flange portion formed outside the lower end of the cylindrical portion 2a. 2b, and the cylindrical portion 2a
On the inner peripheral surface, one support portion 2c is formed, which supports the base end side of the device 10 and through which a hinge 3 for rotatably connecting the receiving frame 2 and the manhole cover 1 is inserted. I have. On the left side of the one support portion 2c, there is formed a first cylindrical portion 2d having a hole (not shown) through which the first arm portion 12 is inserted, and on the right side, A second cylindrical portion 2e having a hole through which the second arm portion 13 is inserted is formed. On the side opposite to the formation position of one of the support portions 2c on which the first and second cylindrical portions 2d and 2e are formed, two not-shown two supporting the front end side of the device 10 described later on the upper surface are provided. The other support is formed. Hereinafter, the configuration of the device 10 will be described in detail. The apparatus 10 comprises the lattice member 11 as a main component.
Is made of ductile cast iron in the same manner as the manhole cover 1 and the receiving frame 2 and has openings (reference numerals are omitted) formed inside the receiving frame 2 as shown in FIG. It is shaped to close almost all of it. As shown in FIG. 2, the grid member 11 has a first vertical grid portion 11a formed in the center and a left vertical grid portion 11a formed on the left side of the first vertical grid portion 11a in parallel with the first vertical grid portion 11a. The second vertical lattice 11b and the first vertical lattice 11
On the right side of a, there is provided a third vertical lattice portion 11c formed parallel to the first vertical lattice portion 11a, and an outer frame portion 11d formed to have substantially the same curvature as the inner periphery of the receiving frame 2. . Inside the outer frame portion 11d, horizontal lattice portions 11e... 11i having a length in a direction perpendicular to the length direction of the first to third vertical lattice portions 11a, 11b, 11c are formed. Have been. An arc-shaped concave portion 11j is formed in the outer frame portion 11d on the left side on the tip side of the first vertical lattice portion 11a. Above the concave portion 11j, an inner periphery of the receiving frame 2 is formed. An arc-shaped mounting portion 11k mounted and supported on the other support portion (not shown) formed on the surface is formed, and an arc-shaped mounting portion is provided on the right side of the tip of the first vertical lattice portion 11a. A concave portion 11l is formed, and an arc-shaped mounting portion 11m mounted and supported on another supporting portion (not shown) formed on the inner peripheral surface of the receiving frame 2 is formed above the concave portion 11l. . The apparatus 10 has first and second lock members 15 and 16. The first and second lock members 15 and 16 are disposed on the left and right sides on the distal end side of the lattice member 11, respectively, and each have a cylindrical case portion (the reference numerals are omitted). Concave portions 11j and 111 formed in the lattice member 11 by an elastic member (not shown) housed in the case portion.
And lock member main bodies 17 and 18 protruding inward. The lower surface of the lock member main body 17 (also the lock member main body 18) has an arc-shaped sliding contact surface 17a which is in sliding contact with the end surface of the other supporting portion (not shown) formed on the inner peripheral surface of the receiving frame 2. Are formed. Further, as shown in FIG. 2, a distal end of a lock release operation cord 19 is fixed to base ends of lock member main bodies 17 and 18 constituting the lock members 15 and 16. Therefore, as described below,
When the lattice member 11 is turned from the upright state to be horizontal, the first and second lock members 15 and
Sliding contact surface 17 of lock member main bodies 17 and 18 constituting
a and 18a contact the other supporting portion formed on the inner peripheral surface of the receiving frame 2 and further press the grid member 11 downward,
The sliding contact surfaces 17a and 18a are slid into the case against the elastic force of an elastic member (not shown) while slidingly contacting the support portion, and further press the grid member 11 downward, completely on the other support portion. , The lock member body 17,
The projection 18 is again projected toward the inner peripheral surface of the receiving frame 2 by the elastic force of the elastic member, and the device 10 is locked to the receiving frame 2 by such an operation. And the lock release operation string 1
When the lock members 9 and 9 are pulled against the elastic force of an elastic member (not shown) so as to be immersed in each case, the locked state is released. Can be erected. As described above, the first arm 12 is formed on the left side of one side of the lattice member 11,
On the right side of one side of the grid member 11, a second arm 1
3 are formed. The first arm section 12 is configured as shown in FIG.
As shown in FIG. 3, the upright plate portion 12a is formed upright from the upper surface of the lattice member 11, and a horizontal plate portion 12b is provided extending horizontally from the upper end of the upright plate portion 12a. A bolt insertion hole 12c is formed in 12b. Further, the second arm 13 is provided with the lattice member 11.
And a horizontal plate portion 1 extending horizontally from the upper end of the upright plate portion 13a.
3b, and a bolt insertion hole 13c is formed in the horizontal plate 13b. The horizontal frame portion 12b constituting the first arm portion 12 has the receiving frame 2
A first retaining member 20 inserted from below into a first cylindrical portion 2d formed on the inner periphery of the bolt 21 and the nut 2
2 so as to be rotatable. In addition, the second
A second retaining member 23 inserted from below into a second cylindrical portion 2e formed on the inner periphery of the receiving frame 2 includes a bolt 24 and a nut 25 on the horizontal plate portion 13b constituting the arm portion 13. It is pivotally fixed as possible. In the upper portions of the first and second retaining members 20, 23, insertion holes (the reference numerals are omitted) in which the horizontal plate portions 12b, 13b are inserted inward and the bolts 21, 25 are inserted inward. ) Are formed in the two opposed plate portions 20a, 20b, 2
3a and 23b are formed, and the first or the second
The retaining flange portions 20c and 23c having an outer diameter larger than the inner diameter of the cylindrical portions 2d and 2e are formed.
Therefore, as shown in FIGS. 1 and 2, when the present apparatus 10 supported substantially horizontally by the receiving frame 2 so as to close the inside of the receiving frame 2 is erected, as shown in FIG. The horizontal plate portion 12b (13b) constituting the first (and second) arm 12 (13) is inserted into the first (or second) cylindrical portion 2d (2e), and each of the upright plates is formed. Part 12
a (13a) is the first (or second) cylindrical portion 2d
The entire device 10 is supported by contacting the upper end of (2e) and does not rotate. Accordingly, the worker can enter the manhole by standing the apparatus 10 in this way, and at this time, put his / her hand or foot on the horizontal lattice parts 11e... 11i constituting the lattice member 11. be able to. When the receiving frame 2 is closed by the lattice member 11 constituting the present apparatus, the lattice member 11 is lifted upward, so that the first or the second cylindrical portion 2 is closed.
By pulling out the horizontal plate portions 12b and 13b inserted in d and 2e, and turning the bolts 21 and 24 in the direction of arrow A in FIG. 5 using the bolts 21 and 24 as pivot shafts, as shown in FIG. The grid member 11 is in a horizontal state, and is locked to the receiving frame 2 by the first and second lock members 15 and 16 by the above-described operation. As described above, according to the manhole fall prevention device 10 according to the above-described embodiment, the lattice member 11 is formed of the same ductile cast iron as the receiving frame 2 and the manhole cover 1, so that the conventional structure is used. Since the mechanical strength is superior to the fall prevention device for manholes and the potential is the same, the progress of corrosion can be effectively suppressed. In addition, as shown in FIG. 1, since the grid member 11 covers substantially the entire inside of the receiving frame 2, it is also possible to effectively prevent tools and tools from falling into the manhole. In the manhole drop prevention device 10 according to the above-described embodiment, the grid member 11 is formed into the shape shown in FIG. 2, but the grid member constituting the present invention is not necessarily formed into such a shape. It is not necessary to mold, and as long as it covers at least substantially the entire opening inside the receiving frame, for example, the number of vertical grid portions (not shown) parallel to the first vertical grid portions 11a is increased. Alternatively, the number of horizontal lattice portions may be further increased. As is apparent from the above description of the embodiment of the present invention, according to the present invention, the lattice member covers substantially the entire opening inside the receiving frame. Therefore, it is possible not only to prevent the worker from accidentally falling into the manhole, but also to prevent a tool or tool from falling into the manhole. Further, the lattice member is made of cast iron. Since this material is the same material as the manhole cover and the receiving frame, it can be easily recycled. Therefore, the progress of corrosion can be suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing an arrangement of a manhole fall prevention device according to an embodiment of the present invention. FIG. 2 is a plan view of a fall prevention device for manholes. FIG. 3 is a side view showing a state in which the inside of a receiving frame is closed by a fall prevention device for manholes. FIG. 4 is an exploded perspective view showing the configuration of one side of the fall prevention device for manholes. FIG. 5 is a side view showing a state where the lattice member is raised from the state shown in FIG. 3; FIG. 6 is a plan view showing a state in which a conventional manhole fall prevention device is provided in a receiving frame. FIG. 7 is a side view of the manhole fall prevention device shown in FIG. 6; DESCRIPTION OF SYMBOLS 1 Manhole cover 2 Receiving frame 10 Fall prevention device for manhole 11 Lattice member 12 First arm portion 13 Second arm portion 15 First lock member 16 Second lock member 19 Lock release operation cord

Claims (1)

Claims 1. A fall prevention device for a manhole, which is supported substantially horizontally on a receiving frame below a manhole cover and is capable of standing up, comprising: a grid member supported by the receiving frame; An arm portion formed on one of the left and right sides of the lattice member and inserted into left and right openings formed inside the receiving frame when the lattice member is raised; and A lock member that locks a state of being supported substantially horizontally, and a release member that releases a lock state of the lock member.The lattice member is formed of cast iron,
A fall prevention device for manholes, which covers substantially the entire opening inside the receiving frame.