JP7205938B2 - Lid receiving frame set for underground structures - Google Patents

Description

TECHNICAL FIELD The present invention relates to an underground structure lid receiving frame set including a receiving frame defining an opening connected to an underground structure and a lid body closing the opening.

In places where underground structures such as sewerage, water supply, electric power, gas, telecommunications, etc., are connected to the ground, receive frames that define openings leading to underground structures and lids that close the openings are installed. An underground structure lid receiving frame set may be installed. In this specification, the state in which the lid main body of the lid is supported by the receiving frame and the opening is closed (the state in which the lid main body is fitted in the receiving frame) is referred to as a closed state. is sometimes called an open lid. Moreover, the lid receiving frame set for underground structures may be abbreviated as a lid receiving frame set.

The lid receiving frame set includes a hinge structure that connects the lid body to the receiving frame so that it can be opened and closed, and a locking structure that prevents illegal dumping and illegal entry, as well as preventing the lid from opening due to the pressure inside the underground structure. are known. In addition, in this specification, the pressure in an underground structure may be called an internal pressure. This locking structure generally consists of a lock member provided on the lid body and a pawl receiving portion provided on the receiving frame (see, for example, Patent Documents 1 to 3, etc.). The lock member has a lock body, a shaft portion for swingably supporting the lock body with respect to the lid body, and a claw portion provided integrally with the lock body. Opening of the lid is blocked when the engaged engagement state is reached. Also, the lid can be opened by inserting a T-shaped or hook-shaped opening/closing tool through the keyhole formed in the lid body and rocking the lock member in a state where the claw portion does not engage the claw receiving portion. . Note that the lid receiving frame set described in Patent Document 1 has a lock member provided with a valve body that closes a keyhole. The lid receiving frame set described in Patent Document 2 has a regulating member that is swingably provided on the lid body separately from the lock member, and the regulating member is provided with a valve body. In this lid receiving frame set, when the valve body is pressed by the opening/closing tool and the regulating member is oscillated, the lock member is oscillated by being pushed by the oscillating regulating member. Further, the lid receiving frame set described in Patent Document 3 includes a regulating member having a valve body and a lock member, and the regulating member and the lock member swing independently by an opening/closing tool inserted through a keyhole. be.

In addition, in these lid receiving frame sets, when the internal pressure increases due to flooding of internal water due to torrential rain or the like, the lid main body rises to a predetermined height relative to the receiving frame, and the claw portion engages with the claw receiving portion. state, and the internal pressure is released from the gap between the lid body and the receiving frame. If the internal pressure still increases, the shaft of the lock member breaks and the lock member separates from the lid body before the sewage pipe or the like is damaged, thereby opening the lid and releasing the internal pressure. By doing so, it is possible to prevent damage to sewage pipes, etc., and also prevent the cover from scattering due to the destruction of the hinge structure, and break the bolts, etc. that fix the receiving frame to the underground structure, and the lid receiving frame set together with the receiving frame will be broken. It also prevents them from scattering. However, recent torrential downpours, also known as guerrilla downpours, have created tremendous internal pressure, causing problems such as scattering of the lock member separated from the lid body and falling onto underground structures. For this reason, a lid receiving frame set has been proposed for the purpose of preventing the entire lock member from being scattered (see, for example, Patent Document 4, etc.).

In the lid receiving frame set described in Patent Document 4, the lock member has a claw portion formed separately from the lock body and a fixing pin for fixing the claw portion to the lock body. The fixing pin has a notch formed on the outer periphery, and when the internal pressure increases and the lid body floats against the receiving frame, the fixing pin breaks at the notch position and the engagement state is released when the internal pressure further increases. be done. This opens the lid to release the internal pressure. According to this lid receiving frame set, it is possible to prevent the claw portion, the fixing pin, and the bolt that attaches the fixing pin to the lock body from scattering or falling, thereby preventing the entire lock member from scattering or falling.

Japanese Patent Application Laid-Open No. 2003-239308 Japanese Utility Model Laid-Open No. 63-45857 JP-A-2-183019 JP 2016-205123 A

However, in the lid receiving frame set described in Patent Document 4, even if the entire lock member can be prevented from being scattered or dropped, a large number of broken and separated fixing pins, claws, bolts, etc. may be scattered. You will fall. As mentioned above, the internal pressure caused by recent torrential rains is tremendous, and it is desired to reduce the number of things that scatter or fall, even if they are small.

In view of the above circumstances, it is an object of the present invention to provide an underground structure cover receiving frame set that is designed to reduce the number of items that scatter or fall when the lock member is destroyed.

A lid receiving frame set for an underground structure of the present invention for solving the above-mentioned objects is a lid receiving frame set for an underground structure comprising a receiving frame defining an opening leading to an underground structure and a lid body closing the opening,
The lid body has a lid body supported on the inner peripheral surface of the receiving frame and a lock member provided on the lid body,
The receiving frame has a claw receiving portion integrally provided at a position below the inner peripheral surface,
The lock member has a lock body, a shaft portion for swingably supporting the lock body with respect to the lid body, and a claw portion provided integrally with the lock body. While engaging with the pawl receiving portion to prevent opening of the opening, when the pawl portion is swung in a state in which the pawl portion does not engage with the pawl receiving portion, the opening is allowed to open,
The claw portion protrudes obliquely upward from the key body, and the thickness of the claw portion increases toward the root from a contact portion that contacts the claw receiving portion in an engaged state in which the claw portion is engaged with the claw receiving portion. is formed as
When the internal pressure of the underground structure increases in the engagement state, the claw portion is broken, the engagement state is released, and the opening is opened,
It is characterized in that the shaft portion and the lock main body have such strength that they do not break even when the internal pressure of the underground structure increases to the pressure at which the claw portion breaks.

That is, the claw portion is weaker than the claw receiving portion. Here, the claw portion may be provided with a notch for adjusting strength (reducing strength). By adopting a mode in which the cut is provided, the portion where the claw portion is to be broken is easily set at the position where the cut is provided. Further, even if the pressure (internal pressure) in the underground structure rises to the pressure at which the claw portion breaks, the shaft portion and the lock body have the strength not to break. The underground structure lid receiving frame set has a hinge structure that connects the lid body to the receiving frame so that it can be opened and closed. Then, the lid may be vertically inverted while being connected to the hinge structure to open the opening.

According to the lid receiving frame set for an underground structure of the present invention, when the internal pressure further increases in the engaged state, the claw portion provided integrally with the lock body breaks to open the opening. be released. Therefore, regarding the breakage of the lock member, the items that scatter or fall are limited to the broken pawl portion, and the number of items that scatter or fall can be reduced. Furthermore, since the claw portion is provided integrally with the lock body, it can be easily manufactured by, for example, casting, and the number of parts is small. The shaft portion may be provided integrally with the lock main body, or may be configured by a pin or the like separate from the lock main body.

Effect of the Invention According to the present invention, it is possible to provide an underground structure cover receiving frame set that is designed to reduce the number of things that scatter or fall in relation to the breakage of a lock member.

1 is a cross-sectional view of a lid receiving frame set for an underground structure according to an embodiment of the present invention; FIG. Figure 2 shows a lock member shown in Figure 1; It is a figure which shows the control member shown in FIG. 1. It is a figure which shows the one end side part in which the nail|claw receiving part was provided in the receiving frame shown in FIG. (a) is a cross-sectional view showing a state in which the lid shown in FIG. 1 is lifted due to an increase in internal pressure above a predetermined level; It is a figure which expands and shows the engagement state with a receiving part. It is a figure which shows a mode that the nail|claw part and a nail|claw receiving part are engaged in a modification.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view of a lid receiving frame set (underground structure lid receiving frame set) that is an embodiment of the present invention. Although FIG. 1 shows the ground G, the ground G may be omitted in other drawings for simplification of the drawing.

FIG. 1 shows a cross section of a lid receiving frame set 10 including a lid body 2 having a disk-shaped lid body 4 and a cylindrical receiving frame 3 for supporting the lid body 2 along a straight line passing through the center of the lid body 4. is shown. In the following description, the left-right direction is referred to as the radial direction, the left side is referred to as the one end side, and the right side is referred to as the other end side, with reference to the cross-sectional view of FIG. A sewer drain pipe, which is an underground facility, is buried at a predetermined depth from the ground surface, and a manhole is provided as an underground facility in the middle of the sewer drain pipe. Both sewage pipes and manholes are equivalent to underground structures. A manhole is a vertical hole that leads from a sewer drain pipe to the surface of the ground, using a framework made by stacking ready-made concrete moldings. The receiving frame 3 is provided on the frame, and an inner peripheral surface 31 defines an opening leading to a manhole which is an underground structure.

The lid body 2 has a lock member 5 , a regulation member 6 and a hinge member 7 in addition to the lid body 4 . The lid body 4 is supported by the inner peripheral surface 31 of the receiving frame 3 to open and close the opening. The lid body 2 shown in FIG. (closed state). The lid body 4 is made of cast iron, and is provided with ribs 41 for reinforcement on its lower surface. The lid body 4 may be made of iron other than cast iron, or may be made of metal other than iron, resin, or concrete. A keyhole 4a for inserting an opening/closing tool is provided in the peripheral portion of one end side of the lid body 4. As shown in FIG.

As shown in FIG. 1, the hinge member 7 is rotatably connected by a shaft 73 to the peripheral portion of the lower surface of the lid body 4 on the other end side. The hinge member 7 has a hook-shaped projection 71 formed in its middle portion and a retaining projection 72 formed in its lower end portion. A hinge seat 33 is provided below the inner peripheral surface 31 on the other end side of the receiving frame 3 . The hinge seat 33 is provided with a through hole 331 through which the hinge member 7 penetrates in the vertical direction, and an engaged portion 332 . A hinge structure is formed by the hinge member 7 and the hinge seat 33, and the lid body 4 can be turned 360 degrees or 180 degrees. When the internal pressure (the pressure inside the manhole) becomes higher than a predetermined value, the lid body 2 is lifted, and the lid main body 4 rises from the closed state, and the claw portions 53 are engaged with the claw receiving portions 32 as will be described later in detail. Then, the hook-shaped projection 71 of the hinge member 7 engages with the engaged portion 332 of the hinge seat 33 . The retaining projection 72 is a portion that abuts on the hinge seat 33 when the lid body 2 is lifted. When the lid body 2 is lifted until the retaining projection 72 abuts on the hinge seat 33, the lid body 4 can be vertically inverted. can.

The lock member 5 and the regulating member 6 are provided on the lower surface of the lid body 4 at the peripheral portion on the one end side. A claw receiving portion 32 is provided at a position below the inner peripheral surface 31 on one end side of the receiving frame 3 . The claw receiving portion 32 is a portion projecting obliquely downward in the cross section of FIG. 1, and will be described later in detail.

2 is a view showing the lock member shown in FIG. 1; FIG. 2(b) is an enlarged right side view of the lock member 5 of FIG. 1, and FIG. 2(a) is a front view of the lock member 5 of FIG. 1 as seen from one end side. 2(a) is the width direction of the lock member 5. As shown in FIG.

As shown in FIG. 2, the lock member 5 has a lock body 51, a pair of shaft portions 52, 52, a claw portion 53, and a pair of guide portions 54, 54, which are integrally formed. It is made of cast iron. As shown in FIG. 2( a ), the lock body 51 has a pair of supporting columns 511 , 511 erected on both sides in the width direction, and a base 512 connecting the pair of supporting columns 511 , 511 on the lower end side. It is substantially U-shaped or substantially U-shaped when viewed from the front. The base portion 512 has a portion that is wider in the width direction than the pair of support portions 511, 511, and this portion functions as a weight. Shaft portions 52 protruding outward in the width direction are provided at the upper end portions of the pair of strut portions 511, 511, respectively. Supported.

As shown in FIG. 2(b), the pawl portion 53 is a portion projecting obliquely upward from the radially outer (left side in the figure) surface of the base portion 512, extending from a root 53b on the side of the lock body 51 to a tip 53a. It is formed so that the thickness becomes thinner as it goes. Further, as shown in FIG. 2(a), the claw portion 53 is arranged at the central portion of the lock member 5 in the width direction. The pair of guide portions 54, 54 are triangular projections, and are provided on both sides of the claw portion 53 in the width direction, as shown in FIG. 2(a). An upper surface of each of the pair of guide portions 54, 54 is formed with an inclined surface 54a that is inclined downward toward the outside in the radial direction. When the internal pressure rises above a predetermined level, the lid body 2 is lifted and the lid body 4 rises from the closed state, and the hook-shaped projection 71 of the hinge member 7 engages the engaged portion 332 of the hinge seat 33 as described above. Then, while being guided by the inclined surface 54a of the guide portion 54, the claw portion 53 is engaged with the claw receiving portion 32 shown in FIG.

FIG. 3 is a diagram showing a restricting member shown in FIG. 1. FIG. In FIG. 1, part of the regulating member 6 is hidden by the lock member 5, but FIG. 3(b) is a right side view showing the regulating member 6 of FIG. ) is a front view of the restricting member 6 of FIG. 1 as seen from one end side.

As shown in FIGS. 1 and 3, the regulating member 6 has a valve body 61 that closes the keyhole 4a of the lid body 4, and is inserted through the insertion hole 62a shown in FIG. 1, the regulating member 6 is swingably supported by the lid body 4 by means of the shaft pin 62 shown in FIG. Further, the restricting member 6 has a weight portion 63 on each side in the width direction of the lower end side portion. The pair of weights 63, 63 and the torsion spring 64 shown in FIG. 1 urge the restricting member 6 in the direction in which the valve body 61 closes the keyhole 4a. As shown in FIG. 1, the pair of weights 63, 63 of the regulating member 6 abut on the right side (inner side in the radial direction) of the lock body 51, and the lock member 5 swings counterclockwise. is regulated.

FIG. 4 is a view showing one end side portion of the receiving frame shown in FIG. 1 where the claw receiving portion is provided. Specifically, FIG. 4A is a plan view of one end side portion of the receiving frame 3 as viewed from above. FIG. 4(b) is a view of one end portion of the receiving frame 3 viewed from the inside in the radial direction, and corresponds to a view of FIG. 4(a) viewed from below. FIG. 4(c) is a cross-sectional view taken along the line AA of FIG. 4(b), and FIG. 4(d) is a bottom view of one end portion of the receiving frame 3 viewed from below.

As shown in FIG. 4, the claw receiving portion 32 is formed in a bag shape (dome shape). Thereby, as will be described later in detail, the claw receiving portion 32 defines a space S (see FIG. 4C) into which the claw portion 53 is inserted when the lid body 2 is lifted.

Even if an attempt is made to open the lid in the state shown in FIG. 1, the pawl portion 53 engages the pawl receiving portion 32 and the opening of the lid is prevented. To open the lid, first, a T-shaped opening/closing tool (not shown) is used to press the valve body 61 to swing the restricting member 6 counterclockwise, and the tip of the opening/closing tool is inserted through the keyhole 4a. Next, the tip of the opening/closing tool inserted through the keyhole 4a swings the lock member 5 so that the claw portion 53 does not engage with the claw receiving portion 32, thereby opening the lid. That is, in the lid receiving frame set 10 of the present embodiment, similarly to the lid receiving frame set described in Patent Document 3, the restricting member 6 and the lock member 5 are independently rocked by an opening/closing tool inserted through the keyhole 4a. It moves.

FIG. 5(a) is a cross-sectional view showing a state in which the lid shown in FIG. 1 is lifted due to an increase in internal pressure above a predetermined level.

When the internal pressure rises above a predetermined level due to torrential rain or the like, the lid body 2 is lifted as shown in FIG. 5(a). Specifically, the lid body 4 floats by a height h, the hook-shaped projection 71 of the hinge member 7 engages with the engaged portion 332 of the hinge seat 33, and the claw portion 53 moves into the space S (see FIG. 4 ( c)) and is in an engaged state in which it is engaged with the pawl receiving portion 32 . As a result, the internal pressure is released from the gap between the lid body 4 and the receiving frame 3 .

FIG. 5(b) is an enlarged view showing the state of engagement between the pawl portion and the pawl receiving portion in the circled portion B in FIG. 5(a). In addition, in FIG. 5(b), in order to simplify the drawing, only the lock member 5 and the receiving frame 3 are shown, and the end face of the receiving frame 3 is shown.

As shown in FIG. 5(b), the claw portion 53 in the engaged state is inserted into the space S (see FIG. 4(c)) and guided by the inclined surface 54a of the guide portion 54. engaged with. In the engaged state shown in FIG. 5(b), the pawl receiving portion 32 is also in contact with the guide portion 54. may be separated from In FIG. 5B, the lock member 5 does not swing in the engaged state, but the claw portion 53 engages the claw receiving portion 32 while the lock member 5 swings counterclockwise. There is also

In this embodiment, the claw portion 53 and the claw receiving portion 32 are in linear or planar contact along the horizontal direction (the width direction shown in FIGS. 2 and 3) orthogonal to the paper surface. The thickness L1 of the contact portion T on the side of the claw portion 53 with which the claw receiving portion 32 contacts is thinner than the thickness L2 of the contact portion T' on the side of the claw receiving portion 32 with which the claw portion 53 contacts. The thickness here refers to the thickness in the direction intersecting in the vertical plane with respect to the contact portions T and T' along the horizontal direction.

In the engaged state shown in FIG. 5, when the internal pressure further increases, the claw portion 53 breaks and the engaged state is released. Here, the location at which the claw portion 53 is broken varies depending on the state of internal pressure, dimensional errors in manufacturing, and the like. A cross section (fractured surface) of the fractured portion is indicated by enclosing it with a dashed-dotted circle.

The claw portion 53 of the present embodiment is such that the width L3 of the fractured surface is larger than the height H, as shown by encircling the circle of the dashed-dotted line, even when the claw portion 53 is fractured at any point. is formed in Here, in the relationship between the geometrical moment of inertia of the height and width when the claw portion 53 breaks, since the force acts on the height to the power of three, the force caused by the dimensional error in manufacturing is greater in the height than in the width. The value of is less accurate. Therefore, if the width L3 of the fracture surface of the claw portion 53 is larger than the height H, the accuracy of the force can be improved, thereby keeping the strength of the claw portion 53 within a predetermined range. become easier. Here, the upper and lower limit values of the strength of the claw portion 53 are determined, for example, from the viewpoint of the biting force of the lid body 4 into the receiving frame 3, the scattering of the lid body 4, and the prevention of the scattering of the lid receiving frame set 10 for each receiving frame 3. is set from In addition, a notch 531 indicated by a dashed line is formed on the side of the claw portion 53 that contacts the claw receiving portion 32 and on the opposite side to weaken or adjust the strength of the claw portion 53. good too. Further, by forming the notch 531, it is possible to set the location where the claw portion 53 is to be broken at a desired position. Parts of the lock member 5 other than the claw portion 53, such as the shaft portion 52 and the strut portion 511, are set to a strength that does not break even if the internal pressure increases to the pressure at which the claw portion 53 breaks.

When the claw portion 53 is broken and the engaged state is released, the hinge member 7 swings around the shaft 73 due to the internal pressure, and the hook-shaped projection 71 is disengaged from the engaged portion 332 of the hinge seat 33 . Next, the lid body 2 is lifted until the retaining projection 72 abuts on the hinge seat 33, and the lid body 4 is vertically inverted. Depending on the state of the internal pressure, the hook-shaped projection 71 of the hinge member 7 may not come off from the engaged portion 332 of the hinge seat 33, and after the lid body 4 is opened to the vertical posture, it may be closed without being turned over. I may go back. In either case, the lid is opened (the opening is opened) to release the internal pressure. As a result, damage to the sewage pipes, scattering of the lid body 4 due to destruction of the hinge structure, scattering of the lid receiving frame set 10 for each receiving frame 3 due to damage to the bolts fixing the receiving frame 3 to the manhole, etc. can be prevented. prevented. In addition, regarding the breakage of the lock member 5, the portion to be broken is limited to the pawl portion 53, so that it is possible to reduce the number of items that scatter or fall. In particular, since the claw portion 53 of the present embodiment is formed so that the wall thickness increases from the contact portion T toward the root 53b, the claw portion 53 is closer to the contact portion T than the root 53b, or to the contact portion. The vicinity of the portion T, that is, the tip 53a side of the claw portion 53 rather than the base 53b is likely to break, and the scattered or dropped fragments can be reduced.

Further, in this embodiment, a guide portion 54 is provided to guide the claw receiving portion 32 so as to come into contact with the tip 53a side of the claw portion 53 . A contact portion T of the claw portion 53 with which the claw receiving portion 32 contacts becomes a support point position of the force applied to the claw portion 53 in the engaged state. Therefore, the closer the contact portion T is to the tip 53a side of the claw portion 53, the greater the force acting on the portion of the claw portion 53 closer to the root 53b than the contact portion T, and the more likely the claw portion 53 is to break. . If the contact portion T is too close to the tip 53a, the state of engagement with the claw receiving portion 32 may become unstable. Moreover, even if the lid is opened for the purpose of illegal dumping or illegal entry, it is necessary to prevent the claw portion 53 from breaking. It is desirable to adjust the position of the contact portion T from these points of view.

Furthermore, as described above, in this embodiment, the claw receiving portion 32 is formed in a bag shape, and in the engaged state, the space S defined by the claw receiving portion 32 (see FIG. 4(c)). The claw portion 53 is inserted into the state. Therefore, when the claw portion 53 is broken, the broken pieces can be prevented from scattering.

Next, a modification of the lid receiving frame set shown in FIGS. 1 to 5 will be described. In the modifications described below, differences from the embodiment shown in FIGS. 1 to 5 will be mainly described. , will be described with the reference numerals that have been used so far, and overlapping descriptions may be omitted.

FIG. 6 is a diagram showing how the claw portion and the claw receiving portion are engaged with each other in the modified example. This modification differs from the lid receiving frame set of the above embodiment in the form of the guide portion 54, and FIG. 6 shows only the lock member 5 and the receiving frame 3, as in FIG. 5B. there is

In FIG. 6A, the inclined surface 54a of the guide portion 54 of the above embodiment is indicated by a dashed line. In comparison, it is formed so as to be higher diagonally outward in the radial direction. Therefore, when the internal pressure increases and the lid body 2 rises from the closed state shown in FIG. swaying to Eventually, as shown in FIG. 6(b), it is guided by the guide portion 54', and the claw receiving portion 32 contacts and engages with the tip 53a side of the claw portion 53 more than in the embodiment shown in FIG. 5(b). be in a congruent state. As a result, the contact portion T is located on the tip 53a side of the claw portion 53, and the claw portion 53 is easily broken.

In this manner, the guide portion 54' guides the contact portion T of the claw portion 53, which the claw receiving portion 32 contacts in the engaged state, to the distal end side, and the position of the supporting point of the force applied to the claw portion 53 is determined. It guides to the tip 53 a side of the claw portion 53 . Further, the guide portion 54' adjusts the support point position of the force applied to the claw portion 53 in the engaged state, and also specifies the support point position.

According to the lid receiving frame set 10 described above, it is possible to reduce the number of items that scatter or fall when the lock member 5 is destroyed.

The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims. For example, in the above-described embodiment, the regulating member 6 and the lock member 5 swing independently of each other. A configuration may be adopted in which the valve body is provided in the lock member and the restricting member is not provided. Further, as in the case of the lid receiving frame set described in Patent Document 2, it is also possible to adopt a mode in which the lock member is pushed by the regulating member that is swung by the opening/closing tool to swing.
In addition, the cover receiving frame set for underground structures described so far is
An underground structure lid receiving frame set comprising a receiving frame defining an opening leading to an underground structure and a lid body closing the opening,
The lid body has a lid body supported on the inner peripheral surface of the receiving frame and a lock member provided on the lid body,
The receiving frame has a claw receiving portion integrally provided at a position below the inner peripheral surface,
The lock member has a lock body, a shaft portion for swingably supporting the lock body with respect to the lid body, and a claw portion provided integrally with the lock body. While engaging with the pawl receiving portion to prevent opening of the opening, when the pawl portion is swung in a state in which the pawl portion does not engage with the pawl receiving portion, the opening of the opening is allowed,
When the internal pressure of the underground structure increases in the engagement state where the claw portion is engaged with the claw receiving portion, the claw portion is broken, the engagement state is released, and the opening is opened. It may be characterized as being

The second underground structure lid receiving frame set described so far is an underground structure lid receiving frame set that includes a receiving frame that defines an opening leading to an underground structure and a lid that closes the opening,
The lid body has a lid body supported on the inner peripheral surface of the receiving frame and a lock member provided on the lid body,
The receiving frame has a claw receiving portion integrally provided at a position below the inner peripheral surface,
The lock member has a lock body, a shaft portion for swingably supporting the lock body with respect to the lid body, and a claw portion provided integrally with the lock body. While engaging with the pawl receiving portion to prevent opening of the opening, when the pawl portion is swung in a state in which the pawl portion does not engage with the pawl receiving portion, the opening is allowed to open,
When the internal pressure of the underground structure increases in the engagement state where the claw portion is engaged with the claw receiving portion, the claw portion is broken, the engagement state is released, and the opening is opened. and
The lock member has a guide portion that guides the pawl receiving portion so as to come into contact with the distal end side of the pawl portion in the engaged state.

That is, the claw portion is weaker than the claw receiving portion. Here, the claw portion may be provided with a notch for adjusting strength (reducing strength). By adopting a mode in which the cut is provided, the portion where the claw portion is to be broken is easily set at the position where the cut is provided. Further, even if the pressure (internal pressure) in the underground structure rises to the pressure at which the claw portion breaks, the shaft portion and the lock body have the strength not to break. The underground structure lid receiving frame set has a hinge structure that connects the lid body to the receiving frame so that it can be opened and closed. Then, the lid may be vertically inverted while being connected to the hinge structure to open the opening. Here, the guide portion adjusts the support point position of the force applied to the claw portion in the engaged state, and also specifies the support point position.

According to the second underground structure cover receiving frame set, when the internal pressure further increases in the engaged state, the claw portion integrally provided with the lock body is broken to open the opening. be released. Therefore, regarding the breakage of the lock member, the items that scatter or fall are limited to the broken pawl portion, and the number of items that scatter or fall can be reduced. Furthermore, since the claw portion is provided integrally with the lock body, it can be easily manufactured by, for example, casting, and the number of parts is small. The shaft portion may be provided integrally with the lock main body, or may be configured by a pin or the like separate from the lock main body. Further, in the engaged state, the contact portion where the claw receiving portion contacts the claw portion, that is, the support point position of the force applied to the claw portion can be guided to the distal end side of the claw portion. As a result, the force applied to the portion of the claw on the side of the lock body increases, and the claw is likely to break.

Further, in the above lid receiving frame set for an underground structure, the thickness of the contact portion with which the claw receiving portion is in contact with the claw portion in the engaged state is such that the claw portion of the claw receiving portion comes into contact with the claw portion. It may be thinner than the thickness of the contact portion where it is.

That is, the moment of inertia of area of the contact portion is smaller at the claw portion than at the claw receiving portion. Here, the thickness refers to the thickness in the direction intersecting in the vertical plane with respect to the contact portion that is in line contact or plane contact along the horizontal direction. The receiving frame, the lock body and the claw portion may be made of the same material, for example, cast iron. The pawl portion may have a wall thickness that increases from the contact portion toward the lock body, that is, a geometrical moment of inertia that increases. By doing so, the claw portion is more likely to break on the contact portion side than the root (the portion on the lock body side), or near the contact portion, i.e., on the tip side of the root, and the broken pieces that scatter or fall will be more likely to break. can be made smaller.

Further, in the above underground structure lid receiving frame set, the claw portion may have a fractured surface with a width larger than a height at a fractured portion after the engagement state.

Width refers to the horizontal dimension.

In the relationship between the geometrical moment of inertia of the height and width in breaking the claw portion, since the force acts on the height to the power of three, the height is greater than the width in terms of the value of the force generated due to the dimensional error in manufacturing. Poor accuracy. Therefore, if the width of the fracture surface of the claw portion is larger than the height, the accuracy of the force can be improved. As a result, the strength of the claw portion is kept within the upper and lower limit values set from the viewpoint of the biting force of the lid body into the receiving frame and the prevention of scattering of the lid receiving frame set for each of the lid body and the receiving frame. easier to collect.
(Appendix 1) Another underground structure lid receiving frame set is an underground structure lid receiving frame set comprising a receiving frame that defines an opening connected to an underground structure and a lid that closes the opening,
The lid body has a lid body supported on the inner peripheral surface of the receiving frame and a lock member provided on the lid body,
The receiving frame has a claw receiving portion integrally provided at a position below the inner peripheral surface,
The lock member has a lock body, a shaft portion for swingably supporting the lock body with respect to the lid body, and a claw portion provided integrally with the lock body. While engaging with the pawl receiving portion to prevent opening of the opening, when the pawl portion is swung in a state in which the pawl portion does not engage with the pawl receiving portion, the opening is allowed to open,
When the internal pressure of the underground structure increases in the engagement state where the claw portion is engaged with the claw receiving portion, the claw portion is broken, the engagement state is released, and the opening is opened. and
It is characterized in that the shaft portion and the lock main body have such strength that they do not break even when the internal pressure of the underground structure increases to the pressure at which the claw portion breaks.

10 lid receiving frame set 2 lid body 3 receiving frame 31 inner peripheral surface 32 claw receiving portion 33 hinge seat 4 lid body 5 lock member 51 lock body 52 shaft portion 53 claw portion 531 notch
54, 54' guide portion 6 regulating member 7 hinge member L1 thickness L2 thickness L3 width T, T' contact portion

Claims (1)

An underground structure lid receiving frame set comprising a receiving frame defining an opening leading to an underground structure and a lid body closing the opening,
The lid body has a lid body supported on the inner peripheral surface of the receiving frame and a lock member provided on the lid body,
The receiving frame has a claw receiving portion integrally provided at a position below the inner peripheral surface,
The lock member has a lock body, a shaft portion for swingably supporting the lock body with respect to the lid body, and a claw portion provided integrally with the lock body. While engaging with the pawl receiving portion to prevent opening of the opening, when the pawl portion is swung in a state in which the pawl portion does not engage with the pawl receiving portion, the opening is allowed to open,
The claw portion protrudes obliquely upward from the key body, and the thickness of the claw portion increases toward the root from a contact portion that contacts the claw receiving portion in an engaged state in which the claw portion is engaged with the claw receiving portion. is formed as
When the internal pressure of the underground structure increases in the engagement state, the claw portion is broken, the engagement state is released, and the opening is opened,
A lid receiving frame set for an underground structure, wherein the shaft and the lock main body have strength not to break even when the internal pressure of the underground structure rises to the pressure at which the claw breaks.

Images