JP2000273888A - Fixing device for manhole cover - Google Patents

Abstract

(57) [Summary] [PROBLEMS] Manhole covers and frames are also specified in JIS standards. The lid is made lighter so that it can be opened and closed. Along with the weight reduction, fixing devices have been devised and implemented in order to prevent rattling of the lid. However, in a manhole, for example, it is expected that the pressure will rise sharply due to a sudden rise in water, and it is difficult to take safety measures only with a fixing device. A lever has a support arm and an arm centered on a boss portion, and an engagement portion is formed on a tip end of the arm.
The bolt 4 is inserted from the side a through a hole formed in the boss portion of the lever via a spherical washer 5, and the square nut 6 of the nut seat is screwed with the bolt 4, and the bolt 4 further protruding from the opening is formed.
, A washer 9 and a spring 7 are attached thereto, and the end of the washer is tightened and fixed with a hexagonal nut 8 so as to press the elongated hole 51 of the pressure receiving plate 50. The lever 2 is always suspended by the spring 7, and
The spring 7 between the and the pressure receiving plate 50 is configured as a buffer member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manhole cover, and more particularly, to a fixing device for securely holding a light-weight cast manhole cover to a frame in a stable state.

[0002]

2. Description of the Related Art JIS (Japanese Industrial Standards) A5506
"Sewer manhole cover" (hereinafter simply referred to as standard)
Has been standardized for its lid (see Figs. 2 and 4 with the same standard) and frame (see Figs. 3 and 5 with the same standard) and is generally well known. According to the standard, the lid and the frame are classified into three types of gray cast iron ( FC200). And for the lid, spheroidal graphite cast iron (for example, FCD500) is used,
The surface is provided with a pattern or a gas vent hole, and a crest is provided at the center to provide a space for decoration or display. Furthermore, on the back side of the lid, although related to the height of the frame, the outer peripheral edge of a fixed height is connected by cross-shaped (overall, cross-girder) ribs to reduce the thickness of the upper plate. By doing so, weight reduction is achieved.

[0003] If this weight reduction is promoted too much, there is a danger that the lid may be lifted by a vehicle running on the lid and cause danger.
Therefore, Japanese Unexamined Patent Publication No. 59-102020 and Japanese Utility Model Application Laid-Open No.
As disclosed in Japanese Patent Publication No. 0-178053 and the like,
By providing a member that is engaged or connected to both the lid and the frame,
It is used as a locking device or a locking device as typified by Japanese Utility Model Publication No. 4-2206, in which a lid is fixed and held to a frame.

According to the above-mentioned publication, the lid is improved and the frame is also improved. That is, even if the lid is replaced, there is a problem that the object cannot be achieved unless the existing frame is replaced. Therefore, the present applicant has disclosed in Japanese Patent Application No. 10-377985 a "lid for manhole" (hereinafter referred to as "lid for manhole"). , The earlier application) to solve the problems.

FIGS. 8 to 10 show Embodiment 1 in the prior application.
The fixing state of the second embodiment will be described with reference to FIGS.

First, in the first embodiment, ribs 14 connected to the outer peripheral edge 11 on the back side of the lid 1 are radially provided by dividing the ribs into six equal parts, and the ribs 12 and 13 are formed at a certain pitch from the center side.
Are formed concentrically and connected to the outer peripheral edge 11. At the intersections of the ribs 13 on the constant pitch and the ribs 14 on the straight line, bolt holes 19 and bolt seats 18 are formed at three places. A pin hole is drilled in the rib 14 at a position separated by a predetermined pitch, and a lever 20 having a saw blade-shaped engaging portion 29 formed at the tip end side is fixed to the hole by the pin 3 so as to be swingable in the radial direction. The bolt 4 is inserted into the bolt hole 19, and the square nut 6 of the nut seat 24 provided on the lever 20 and the bolt 4 are screwed together. After tightening with the hexagonal nut 8, the locking pin P is driven in and fixed, and the spring 7 is constantly urged to support the lever 20.
After fitting a into the frame 10, the bolt 4 is rotated so that the engaging portion 29 comes into contact with and bites into the inner wall surface of the frame 10 so as to be firmly engaged.

In the second embodiment, a hole 40 formed in the cover 1b by mounting a mounting plate 30 integrally formed with the bolt hole 19b, the bolt seat 18b and the mounting projection 31 is aligned with the bolt hole and the bolt seat 18b. On the other hand, the lever 20 is fixed to the mounting plate 30 by the pin 3 on the mounting protrusion 31, the bolt 4 is inserted through the bolt hole 19 b, and the nut seat 24 provided on the lever 20 is fixed. The bolt is screwed into the square nut 6, and a spring 7 is mounted on the bolt and tightened with a hexagonal nut 8 at its tip to drive a detent pin P, thereby compressing the spring and constantly biasing the spring. The lever is configured to be supported upward, and after the cover 1b is fitted into the frame 10, the bolt is tightened from the outside and the lever 20
The engaging portion 29 is engaged with the inner wall surface of the frame.

[0008]

As described above, the first embodiment proposes that the lid 1a is newly used to use the existing frame 10, and the second embodiment proposes that the lid 1b and the frame 10 are used as they are. ing. A lever 20 having an engagement portion 29 having a saw blade at the tip bites into the frame 10. In other words, the tip of the lever 20 makes an arc movement around the pin 3, but the square nut 6 supporting the lever 20 causes the tip of the lever 20 to be at a right angle to the bolt as the bolt 4 becomes upright. Move in the direction to frame 1
It is designed to cut into the wall of the hole H0. However, the frame 10 is cast and lacks roundness as compared with the machined one, and the lever 20 having a constant length is bolted after the lid 1a (1b) is closed. 4 is tightened, and 1) it is difficult to confirm whether the engagement portion 29 is engaged with the inner wall surface of the frame 10. 2) In the manhole, for example, there is a danger that the internal pressure increases due to a sudden increase of water and the lid is pushed up. It has become clear that such issues must be solved.

[0009]

Therefore, a small arc-shaped depression is provided on the wall surface of the frame at a position facing the lever attached to the lid, and the lever is provided at the tip of the arm obliquely inclined from the boss.
An engaging portion substantially parallel to the boss portion is formed, and the frame is sandwiched and fixed between the engaging portion and the lid. That is,
The lever fixed by the pin rotates the bolt screwed to the square nut in the tightening direction to move the lever upward, and with the movement, the engaging portion enters the recess, and further the bolt The first feature is that the frame is firmly clamped and fixed between the lid and the lever by tightening.

A second feature is that a pressure receiving plate is provided which further increases the engagement between the lever and the frame as the pressure in the manhole increases. This pressure receiving plate has an umbrella shape, and tries to transmit the pressure to the boss of the lever by receiving the internal pressure.However, since the spring is always acting, the pressure is not transmitted to the lever suddenly. It has become.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As described above, the present invention is an improvement on the prior application, and FIGS. 8 to 12 refer to the drawings of the earlier application. Therefore, the reference numerals and names of the parts are the same as those used in the prior application except for the lever 20 and the engaging portion 29 at the tip thereof in the first and second embodiments described in the previous application. This will be described in detail below.

The lever 2 will be described with reference to a side view of FIG. 3, a plan view taken along the line AA (FIG. 4) and a side view taken along the line BB (FIG. 5). The support arm 21 is bifurcated parallel to and inclined to the upper right (FIG. 3), and a pin hole 26 is provided at the end thereof. The arm 23 is inclined to the boss (FIG. 4). In the figure, an engaging portion S is formed at the front end of the boss 22 in a flat shape and substantially parallel to the upper surface of the boss 22 (or the lower surface serving as the square nut seat 24). A hole 25 penetrating in the vertical direction is formed in the boss 22 in a direction perpendicular to the nut seat 24, and an opening 28 is formed by the formation of a locking portion 27 for controlling the movement of the nut 6. Arm 23 and hole 2
The center line of No. 5 is aligned and guided.

The engaging portion S is formed to have a length that can be inserted into a recess V provided in the wall surface of the hole H1 of the frame 10, and the tip T has a tapered relief slope. That is, boss 2
The lever 2 fixed to the support arm 21 by the pin 3 is turned by the bolt 4 inserted into the hole 25 of the second arm 25, and the arm 23 and the engaging portion S are pivoted about the pin, but the movement is caused by the boss 22 being moved. The rotation of the bolt 4 screwed to the supporting square nut 6 changes the position of the square nut 6. Therefore, when the bolt 4 is tightened, the tip of the arm 23 moves along with the locus of the arc and the square nut 6
The two parts are guided and move with the forward movement. Further, since the lever 2 has one end restrained by the pin 3, the engagement part S rapidly enters the recess V as the bolt 4 is tightened, As the boss 4 becomes upright, the boss 22 is guided by the square nut 6 and the boss 22 travels in a direction perpendicular to the bolt 4, in other words, in the radial direction to the hole H 1, so that the tip T Has a clearance gradient (FIGS. 2, 3, and 6).

Further, the bolt 4 is attached to the boss 2 from the lid 1a side.
2 is screwed into the square nut 6 of the nut seat 24, and the square nut and the bolt 4 protruding from the opening 28 are inserted through the hole 25.
A spring 7 is mounted on the distal end side of the spring through washers 9 and 9, and the spring is always urged by a nut 8 and a pin P. For example, when the bolt 4 is turned in the tightening direction by the spring bias, the square nut 6 moves so as to lift the lever 2, and the movement of the square nut causes the lever 2, one end of which is fixed by the pin 3, to move as described above. As shown in FIG. 6, the bolt 4 and the lever 2 are erected from the position shown by the two-dot chain line (thin line) as shown in FIG. At the same time, the engaging portion S and the recess V are joined so as to sandwich the frame 10.

In the frame 10, below the peripheral edge of the inner wall of the hole H1,
An arc-shaped depression V is provided so that the tip T can freely enter and exit. Depending on the number of levers 2 to be attached to the lid 1, the recesses V are equally divided, for example, three in three places and four in four places, but an existing frame is used. In some cases, after positioning by jig alignment, hanging work and grinder finishing are performed on site, and in the case of a new case, a dent V is installed in the frame 10 around the inner wall of the hole H1 from the time of casting ( Hereinafter, description of the depression V will be omitted in the embodiment.

Next, FIG. 7 shows a case where an existing lid 1b is used. However, a hole 40 is formed in the lid 1b at a fixed position by adjusting a jig, and the mounting plate 30 is positioned around the hole. Then, a hole (not shown, see FIG. 11) for the mounting bolt 35 of the mounting plate is provided, and the mounting plate 35 is mounted on the back surface of the lid 1b. A mounting projection 31 is integrally formed on the mounting plate 30 together with the bolt seat 18b and the bolt hole 19b.

After assembling the lever 2 to the lids 1a and 1b at predetermined positions with the bolts 4 and the square nuts 6, the opening 28
The washer 9, the spring 7, and the washer 9 are inserted into the bolt 4 protruding from the portion, and further, an umbrella-shaped pressure receiving plate 50 is formed.
Is fixed with a washer 9 and a hexagon nut 8, and the hexagon nut 8 is fixed with a pin P so as to always bias the spring 7. The pressure receiving plate 50 is formed by drawing a steel plate to form a reinforcing rib 52.
Is welding. Also, 51 is an oblique state shown by a two-dot chain line (thin line) when the bolt 4 is attached, as shown in FIG. 6, but in the center direction so that the bolt 4 can move according to the tightening. It is a long hole drilled toward it. The reason that the concave side of the pressure receiving plate 50 faces downward is to make it easier to receive the pressure in the manhole. Then, as shown by a two-dot chain line (thin line) in FIG.
When the pressure is received, the pressure of the pressure receiving plate 50 is buffered by the spring 7. Further, the pressure receiving plate 50 may be omitted when there is no possibility that the pressure in the manhole changes abruptly, but it is preferable to provide the pressure receiving plate 50 from the viewpoint of safety.

[0018]

FIG. 1, FIG. 2 and FIG. 6 show an improvement of the first embodiment of the prior application (hereinafter referred to as a third embodiment).
FIG. 7 illustrates an improved example (hereinafter, referred to as a fourth embodiment) of the second embodiment.

First, in the third embodiment, the ribs 1 which are concentrically arranged with respect to the outer peripheral edge 11 and the ribs 13 having a constant pitch and the ribs 13 having a constant pitch are radially arranged by dividing into six equal parts.
4 are continuously integrated. The lid 1a, in which the bolt seat 18 and the bolt hole 19 are formed at the intersection of the rib 13 with a constant pitch and the linear rib 14, is perpendicular to the rib 14 at a position separated from the bolt hole 19 by a predetermined distance. Holes are drilled in the direction. The hole is connected to this hole by a pin 3 via a pin hole 26 of the lever 2, the pin is prevented from falling off (not shown), and the lever 2 is swingably fixed by the pin.

Then, the bolt 4 is inserted together with the spherical washer 5 from the bolt seat 18 side, and further, the hole 25 of the boss 22 is inserted therethrough. The square nut 6 in the nut seat 24 (a hexagon nut may be used, but the square nut is The bolt is screwed together with the bolt, and the bolt is turned in the tightening direction to protrude from the opening 28 so that the washer 9, the spring 7, the washer 9 and the pressure The plate 50 and the washer 9 are assembled into the protruding bolt 4, the hexagonal nut 8 is screwed, and the detent pin P is firmly driven into the nut side.
By this assembly, the spring 7 is compressed and suspends the lever 2 to maintain the interval between the lever 2 and the pressure receiving plate 50. When the pressure rises in the manhole, the pressure receiving plate 50
, The pressure is buffered by the spring 7, and the lever 2 does not give a great impact to the lever 2. Rather, the lever 2 firmly secures the fixing relationship between the engaging portion S and the upper side of the recess V. I do. Then, the difference in the area between the hole H0 of the manhole or the hole H1 of the frame 10 and the pressure receiving plate 50 is determined by using the cover 1
a (1b) is transmitted with a slight delay. The state of the mounting is shown by a two-dot chain line (thin line) in FIG. 6, but the spring 7 is compressed from below the opening 28 to be in a biased state, so that the spring 7 is supported by the locking portion 27. Thus, the square nut 6 is restrained, and the lid 1a is fitted into the hole H1 of the frame 10 in a state where the spring is held between the square nut 6 and the pressure receiving plate 50.

When the lever 2 is fitted in the frame 10 with the lever 2 attached at three places, and the bolts 4 are tightened on average, the tightening tool (for example, a wrench) cannot be rotated. That is, as shown by the solid line in FIG. 6, the position changes from the two-dot chain line (thin line) to the position indicated by the solid line, and the tip T side enters the recess V as the bolt 4 becomes upright,
On the other hand, since the lever 2 has one end fixed by the pin 3 and supported by the spring 7, when the engaging portion S comes into contact with the upper side of the recess V, the square nut 6 separates from the locking portion 27, The rotation of the bolt 4 is lightened. Further, when the bolt 4 is rotated in the tightening direction, the square nut 6 comes into contact with the upper surface of the nut seat 24 (below the boss 22) to complete the tightening.

Next, since the fourth embodiment is an improvement over the above-described second embodiment, a lever 2 having an engaging portion S and a tip T (FIG. 3) is used instead of the lever 20 (second embodiment, FIG. 2).
5) and the mounting plate 30, the mounting projections 31, and the bolts 35 are the same as those shown in FIG. 11, so that the description will be made with reference to FIG. 11 in addition to FIG. .

The lid 1b is provided with a hole 40 at a fixed position by adjusting the jig.
, And a hole of the mounting bolt 35 is installed around the hole,
After the tapping, the bolt 35 is tightened to fix the mounting plate 30 while aligning the bolt seat 18b with the hole 40. The mounting plate 30 is integrally formed with a mounting projection 31 together with the bolt seat 18b and the bolt hole 19b. A bifurcated support arm 21 is attached to the projection via a pin 3 so as to be freely swingable in one direction, and a bolt 4 is inserted from a bolt seat 18b side into a hole 25 of a boss 22 via a spherical washer 5. And screwed into the square nut 6 to further protrude the bolt 4. The protruding bolt 4 has a washer 9, a spring 7, a washer 9 and a pressure receiving plate 50.
Each of the long holes 51 is inserted, and the hexagon nut 8 is tightened so that the long holes 51 are pressed by the washer 9, and a pin P is driven into the holes to integrate them. At this time, the engaging portion S and the tip T are at the position indicated by the two-dot chain line (fine line) as shown in FIG. 7, and the spring 7 is located between the lever 2 and the pressure receiving plate 50.
And the pressure receiving plate 50 are separated from each other, and both are assembled by the bolts 4 in a suspended state.

In this state, when the cover 1b is fitted into the frame 10 and the bolts 4 are tightened in the tightening direction, the spring 2 is in the biased state, as described in the third embodiment. Further, the lever 2 can be lightly rotated so that the lever 2 temporarily turns idle when the recess V comes into contact with the engaging portion S without requiring any urging force. Are brought into contact with each other and firmly tightened, so that the lever 2 and the lid 1b are fixed so as to sandwich the frame 10 therebetween.

In the third and fourth embodiments, when removing the fixed lids 1a and 1b, the cover 1a and 1b are rotated in the direction opposite to the tightening direction until the square nut 6 contacts the locking portion 27. During this time, the rotation is light, and when the square nut 6 descends and comes into contact with the locking portion 27, the spring 7 is compressed, and the engaging portion S, which has been in contact with the recess V, is completely disengaged. Due to the compression, the engaging portion S is separated from the recess V, and the bolt 4 and the lever 2 move to the position indicated by the two-dot chain line (fine line) in FIG. When the spring 7 starts to compress, the bolt 4
Since the tool (for example, a wrench) that rotates the wrench also feels the weight, it can be understood that the engagement portion S has completely released the coupling from the recess V. If the number of rotations of the tool is determined from the time when the weight is felt, the compression amount of the spring 7 is also determined by the pitch of the bolt 4, so that the position of the lever 2 when opening and closing the lid 1 can be kept constant.

In these embodiments, components such as various bolts, washers, nuts and springs are used in an atmosphere in which gas is generated and are in a corrosive environment, so that they are hardly affected by rust such as stainless steel. It goes without saying that the selection from the materials is made deeply. In the figure, GL is the ground surface, and H0 is a manhole made of concrete.

[0027]

According to the present invention, a lever whose one end is connected by a pin so as to sandwich a rib or a mounting projection by a bifurcated support arm is guided by the rib or the mounting projection, and is screwed with a bolt. Since the lever is suspended and supported by a spring mounted on the bolt and further guided by an opening formed by a locking portion provided on the lever, the bolt is guided by the square nut and moved, Move the lever exactly in the direction of the depression. Therefore, the safety can be enhanced because the frame can be firmly connected by the engagement portion and the lid in the depression.

Also, since the spring is always urged against the lever, the engaging portion enters into the recess, and the bolt is further tightened. It can be easily understood that the frame is fixed so as to sandwich the frame with the lever. Therefore, the fastening can be easily determined by the operator.

Further, since the pressure receiving plate is provided, even if the pressure rises abruptly in the manhole, the pressure generated by the pressure receiving plate is once received, and the pressure is immediately transmitted to the spring, and the pressure is immediately transmitted to the lid side. However, the pressure transmitted to the spring deflects the spring and makes the connection of the lever more firm, so that the pressure corresponding to the difference between the diameters of the manhole and the pressure receiving plate is slightly delayed and the lid is closed. Since the pressure is transmitted to the side, the elevated pressure is not directly applied to the lid. Therefore, the invention is significant from the viewpoint of safety.

[Brief description of the drawings]

FIG. 1 is a front view of the back side of a lid according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional side view of a covered manhole.

FIG. 3 is a side view of the lever according to the present invention.

FIG. 4 is a plan view taken along the line AA in FIG. 3;

FIG. 5 is a side view taken along the line BB in FIG. 3;

FIG. 6 is a sectional view of a main part of a third embodiment according to the present invention.

FIG. 7 is a sectional view of a main part of a fourth embodiment according to the present invention.

FIG. 8 is a front view of the back side of the lid of the first embodiment in the prior application.

FIG. 9 is a partial cross-sectional view of a manhole according to the first embodiment.

FIG. 10 is a sectional view of a main part of the first embodiment.

FIG. 11 is a front view of the back side of the second embodiment in the prior application.

FIG. 12 is a sectional view of a main part of the second embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 lid (1a lid) (1b lid) 2 lever 3 pin 4 bolt 6 square nut 7 spring 10 frame 21 support arm 22 boss 23 arm 24 nut seat 25 (boss 22) hole 26 pin hole 27 locking portion 28 opening 30 Attachment plate 31 Attachment protrusion 50 Pressure receiving plate S Engagement part T Tip V Depression

Claims (3)

[Claims] 1. A fixing device for a manhole cover, comprising: an iron frame provided at an upper portion of a hole; a cover being fitted into the frame, the hole being closed, and the cover being fixed or locked after the closing; The boss has a hole vertically penetrating therethrough and a nut seat and a locking portion provided therebelow to form an opening, and in parallel with the opening upward from the boss. A support arm inclined obliquely in a fork and an arm inclined obliquely downward in a direction opposite to the support arm are integrally provided,
The support arm has a lever configured to have a mounting pin hole, and the lever is pin-fixed to a rib provided on the lid side or a mounting projection protruding from a mounting plate with the pin hole. A bolt is inserted from the lid side into the boss portion, screwed with the square nut, suspended from the inside of the lid, and a spring is mounted on the bolt tip side projecting from the opening, and the lever is pushed up by the spring. A fixing device for a manhole cover, characterized in that the device is supported so as to urge in a direction. 2. A recess is provided below the iron frame, and an engaging portion substantially parallel to the nut seat is provided at an end of the arm of the lever. When the bolt is tightened, the recess is formed in the recess. The fixing device for a manhole cover according to claim 1, wherein the engaging portion enters, and the frame is held and fixed by the cover. 3. Below the bolt to which the lever is attached,
3. The fixing device for a manhole cover according to claim 1, wherein a pressure receiving plate made of an umbrella-shaped steel plate is fixed.