JP3008446U - Footrest for manhole and its mounting structure - Google Patents

Abstract

(57) [Summary] [Purpose] The embedded part of the footrest in the manhole is projected to the outside of the manhole, and it is fixed with a simple part with good sealing performance. [Structure] In a structure in which a U-shaped foot hanger has embedded portions 2b provided at both ends projected from the inside of a manhole wall and fixed with nuts 5, the base end portion of embedded portion 2b follows the manhole wall. The collar 3 is formed, and the diameter of the base end side of the embedding portion 2b is increased from the tip end side, and an annular surface 4 is formed by a step portion at this connecting portion.
Formed of an elastic member that is inserted into the embedded portion 2b.
A bush 16 having an outer shape of a truncated cone and having a fitting hole is provided, and a plurality of holes 18 are provided in an annular shape on the lower surface of the bush 16 having a truncated cone shape. Since the bush 16 is inserted into the mounting hole (through hole) together with the embedding portion and tightened with the nut 5, the manhole wall in contact with the bush 16 and the embedding portion 2b are brought into close contact with each other by a radial force. This prevents leakage of contaminated air, drainage, etc. inside the manhole.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a footrest for a manhole in which a footrest installed in a manhole is fixed from outside the manhole, and a mounting structure thereof.

[0002]

[Prior art]

 Conventionally, there are two types of footrests used for manholes, which are I-shaped and U-shaped, and are generally provided integrally on the inner wall of a manhole made of concrete. When replacing the footrest, a hole is made in the inner wall of the manhole and it is embedded again. In order to avoid this complicated drilling work, a through hole was made in the manhole wall, the embedded part of the footrest was inserted into the through hole, and the embedded part inserted from outside the manhole was fixed. The thing of the structure is manufactured.

[0003]

[Problems to be solved by the device]

 By the way, usually, when fixing the embedded portion inserted into the through hole externally, a structure in which a screw portion is formed at the tip of the embedded portion and tightened with a nut is used. However, considering the hermeticity, even if a plate-shaped packing is used, the supporting force in the direction of entry of the embedding part will be applied to the packing, and the packing will be easily deformed in the axial direction, which will affect the hermeticity. It will be.

An object of the present invention is to provide a footrest for a manhole and a mounting structure for the manhole so that the footrest for the manhole is fixed to the outside of the manhole with a simple component to improve the airtightness.

[0005]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention has a structure of a footrest for a manhole, in which a footrest whose both ends are bent and an embedding portion are provided at the tip of the footrest, and the embedding portion is projected outward from the inside of the manhole wall. In the U-shaped footrest for manholes that is fixed with a nut, form a collar that imitates the manhole wall at the base end of the embedded part and expand the diameter of the base side of the embedded part from the tip side. An annular surface is formed by a stepped portion at the connecting portion of the lever, and at the tip of the embedding portion, an outer shape made of an elastic member is formed into a truncated cone shape, and a bush having a fitting hole at the center thereof is embedded in the bush. The bush was fitted into the insertion portion from the small diameter surface side.

In the above foot hanging device, a plurality of holes in a direction along the axis line are provided around the fitting hole on a large-diameter frustoconical surface of the bush.

In addition, in the mounting structure of the foot hanging device described above, the through hole formed in the manhole wall for inserting the embedded portion of the U-shaped foot hanging device has the axial center of the through hole formed in the outer wall of the manhole. To the mounting surface that is orthogonal to the inner surface, and the opening of the mounting surface is made larger than the opening opened in the inner wall to form an inclined surface in the axial direction on the inner periphery, and the embedded portion is inserted from the inside of the manhole into the through hole. The collar formed on the base of the embedded portion along the manhole wall, and when the embedded portion is inserted, an annular surface formed by forming a step in the intermediate portion of the embedded portion and the mounting surface. Insert a bush made of an elastic member in the shape of a truncated cone with a height larger than the distance between the bush and the small diameter surface toward the annular surface, and tighten the nut so that the bush is pressed into the through hole. It is characterized by that.

[0008]

[Action]

 The present invention is configured as described above, and the footrest for manhole is fixed in a stable state because the length of the embedded portion is determined by the collar and the collar contacts the wall of the manhole. . Further, since the bush has an appropriate elasticity due to the plurality of holes and the circumferential surface of the bush is inclined, the bush can be easily inserted into the through hole for mounting the footrest. On the other hand, the annular surface of the embedded part controls the invasion of the bush.

Further, by installing the above-mentioned foot hanger on the manhole wall, the peripheral surface of the bush presses the through hole formed in the manhole wall with a force in a substantially radial direction, and the inner hole of the bush becomes the embedded part. The outer peripheral surface is pressed with a force in a substantially radial direction.

[0010]

【Example】

 Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. As shown in FIG. 1, a U-shaped footrest 2 installed on the manhole wall 1 has a footrest 2a whose both ends are bent and an embedded portion 2b which is connected to the tip of the footrest 2a. A collar 3 is formed at the base end of the embedding part 2b following the manhole wall 1, and the base end side of the embedding part 2b is expanded from the tip end side to form an annular surface 4 (stepped) in the middle part. 2) is formed, and a threaded portion 6 into which a nut 5 is screwed is formed at the tip of the embedded portion 2b. Further, an inclined portion 7 having a diameter larger than that of the screw portion 6 is provided between the annular surface 4 and the screw portion 6.

Further, the fine concavo-convex shape 8 formed on the surface of the brim 3 and the footrest 2a and the stopper 9 projectingly formed on the concavo-convex shape 8 are intermediate between the footrest 2a and the embedded portion 2b of the footrest 2. It is integrally formed of synthetic resin that covers the part. Further, the inner side surface 2c of the footrest 2a is formed in a corrugated shape, and the reflection plate 10 is provided at the bent portion of the footrest 2a.

A recess 11 is formed on the outer wall of the manhole wall 1, and a through hole 12 communicating with the inside of the manhole is formed in the recess 11. A mounting surface 13 that directly intersects the axis of the through hole 12 is formed in the recess 11. The mounting surface 13 may be raised on the outer wall of the manhole without forming the concave portion 11, but it is necessary to lengthen the screw portion 6. The through hole 12 expands the opening of the recess 11 from the inner opening of the manhole, and the inner wall of the through hole 12 forms an inclined surface 14 with respect to the axis.

As shown in FIG. 2, a collar 3 is formed on the base of the embedded portion 2b, and an annular surface 4 is formed on the synthetic resin coated end which is an intermediate portion of the embedded portion 2b. The nut 5 for fixing the embedded portion 2b is one in which an elastic packing 15, a bush 16 having an outer shape of a truncated cone and a washer 17 made of steel are inserted into the embedded portion 2b and tightened. The outer diameter of the packing 15 is larger than the outer diameter of the collar 3 and is aligned with the surface of the collar 3.

The bush 16 is formed of an elastic member, and a plurality of holes 18 are annularly provided around the fitting hole 19 at the center on the large-diameter surface 16 a of the bush 16, and the fitting hole 19 is a bush. The side of the small diameter surface 16b of 16 is enlarged and fitted to the inclined portion 7. The height (length) of the truncated cone shape of the bush 16 is larger than the distance between the annular surface 4 and the mounting surface 13 when the embedded portion 2b is inserted. Further, the peripheral surface 16c of the bush 16 is formed as an inclined surface that matches the inclined surface 14 of the through hole 12.

As described above, when attaching the footrest 2 described above to the manhole wall 1, the embedded portion 2b having the packing 15 inserted therein is inserted into the through hole 12, and the bush 16 is inserted into the embedded portion 2b protruding from the attachment surface 13. Then, insert the washer 17 and tighten the nut 5. At this time, since the mounting surface 13 is orthogonal to the axis of the embedded portion 2b, the tightening force of the nut 5 is evenly applied to the surroundings. Further, since the small diameter surface 16b of the bush 16 is inserted toward the annular surface 4, the peripheral surface 16c of the bush 16 is aligned with the inclined surface 14 of the through hole 12 and the bush 16 is press-fitted by tightening with the nut 5.

When the tightening force of the nut 5 is strong, it is buffered by the hole of the bush 16, and the inner peripheral surface of the fitting hole of the bush 16 and the inclined portion 7 of the embedded portion 2b have a substantially radial force. Then, the peripheral surface 16c of the bush 16 and the inclined surface 14 of the through hole 12 are pressure-bonded by a substantially radial force. As a result, the through hole 12 is sealed, the rust preventive effect is enhanced, and leakage of contaminated air, drainage, etc. inside the manhole can be prevented.

[0017]

[Effect of device]

 Since the present invention is configured as described above, since the foot fitting attached to the manhole wall inserts the bush into the embedding part and tightens it with the nut, the foothold and the manhole wall in contact with the bush are embedded. The parts are brought into close contact with each other by a radial force. The through-hole can be reliably sealed with such a simple component to prevent leakage of contaminated air, drainage, etc. inside the manhole.

[Brief description of drawings]

FIG. 1 is a plan view of a footrest attached to a manhole wall according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a main part of an embedded portion of the footrest shown in FIG.

[Explanation of symbols]

 1 Manhole wall 2 Foot hook 2a Foot hook 2b Embedded part 3 Tsuba 4 Annular surface 5 Nut 12 Through hole 13 Mounting surface 16 Bush 18 hole

Claims (3)

[Scope of utility model registration request] 1. A U-shaped footrest for a manhole in which a footrest having both ends bent and an embedding part provided at the tip thereof are projected outward from the inside of the manhole wall and fixed with a nut. A brim is formed at the base end of the embedding part following the manhole wall, and the base end side of the embedding part is expanded from the tip end side to form an annular surface by a step at the connecting part. At the tip of the insertion portion, an outer shape made of an elastic member is formed into a truncated cone shape, and a bush having a fitting hole at the center thereof is inserted into the embedded portion from the small diameter surface side of the bush. The man foot hanger. 2. The footrest for a manhole according to claim 1, wherein a plurality of holes extending in a direction along the axis are provided on a large-diameter frustoconical surface of the bush around the fitting hole. 3. A through hole formed in a manhole wall for inserting an embedded portion of a U-shaped foot hanger is opened in a mounting surface orthogonal to an axis of the through hole formed in an outer wall of the manhole, The opening of the mounting surface is made larger than the opening opened in the inner wall to form an inclined surface in the axial direction on the inner periphery, and the embedded portion is inserted into the through hole from the inside of the manhole to form a base portion of the embedded portion. When the formed brim is placed along the manhole wall and the embedded portion is inserted, a height larger than the distance between the mounting surface and the annular surface formed by forming a step in the intermediate portion of the embedded portion Attachment of a manhole foot fitting characterized in that a bush made of a truncated cone-shaped elastic member is inserted with its small diameter surface facing the annular surface and is tightened with a nut so that the bush is pressed into the through hole. Construction.