JP5146740B2 - Step mounting structure - Google Patents

Description

  The present invention relates to a step mounting structure for manholes constructed when water and sewage systems, power supply lines, telephone lines and the like are laid underground.

  Usually, on the inner wall surface of a concrete manhole, a plurality of steps for an operator to move up and down are attached at predetermined intervals in the vertical direction, and a ladder-like one is formed as a whole. This step generally has a substantially U-shape, and is composed of a central portion on which an operator hangs his limbs, followed by both side portions. On both side portions, mounting portions are formed which are inserted into mounting holes formed in the manhole wall. A threaded portion is formed at the tip of the mounting portion, and when the mounting portion is inserted into the mounting hole, a nut via a packing and a washer is screwed into the threaded portion from the manhole outer wall side, and the step is moved to the manhole. Installation fixed.

  Patent Document 1 below discloses an invention in which a cover ring is provided at a position in contact with a wall portion in the vicinity of an attachment portion of a step attached to a manhole wall portion. According to the cover ring according to the present invention, the chip end chipping that occurs when the mounting hole for attaching the step to the wall portion of the manhole is formed is filled with the viscoelastic filler provided on the inner surface of the cover ring. be able to.

JP 2000-45310 A

However, although the cover ring described in Patent Document 1 functions as a member that closes the chip end of the step attachment hole, the cover ring itself is made of an elastic material such as synthetic resin. It did not have a function to supplement the mounting strength of the step. Further, since the cover ring is pressed against the inner wall surface of the manhole by tightening the nut from the opposite side of the wall portion, it is not easy to tighten the nut again after the manhole is constructed.
Furthermore, the method of injecting adhesive into the mounting hole and inserting the step mounting portion into the mounting hole and fixing it by solidifying the adhesive is not the method by tightening the nut from the opposite side of the wall. The pressure contact strength to the wall surface was not strong.

  Accordingly, the present invention has been made in view of such circumstances, and an object of the present invention is to provide a step attachment structure capable of closing the opening on the inner wall surface side of the step attachment hole by the cover ring. . It is another object of the present invention to provide a step mounting structure that can supplement the step mounting strength by the cover ring itself.

In order to solve the above-mentioned problem, the invention of the step mounting structure according to claim 1 is the step mounting structure in which the mounting hole is provided in the wall portion of the concrete manhole, and the step is attached to the mounting hole. An annular step provided in the mounting hole, a sleeve having a plurality of openings provided in a peripheral wall and a flange seated on the annular step being inserted into the attachment hole and closed at the bottom side , and attachment of the step and adhesives filled through each opening of the sleeve between the parts and the mounting hole, and the locked portion provided on the peripheral surface of the portion adjacent to the mounting portion of the step, around the step And a cover ring that engages with the locked portion and that covers the mounting hole of the wall portion, and the locked portion includes a concave groove portion, Stop part from protrusion The cover ring is made of a rigid member, and when the projection is engaged with the concave groove portion of the step by being pushed toward the mounting portion of the step, the front surface of the cover ring contacts the flange of the sleeve. In contact therewith, the cover ring closes the mounting hole on the inner wall surface of the manhole, and a part thereof is fitted into the mounting hole .

An annular step portion is provided on the inner wall surface of the step mounting hole provided in the wall portion of the manhole, and a sleeve is inserted into the mounting hole, and the flange of the sleeve is seated on the annular step portion of the mounting hole. A plurality of openings are formed in the peripheral wall of the sleeve, and an adhesive is filled between the step attachment portion and the attachment hole through each opening of the sleeve.
Further, the step is formed, for example, in a substantially U shape, and is composed of a central portion where an operator hangs his / her limbs and both side portions which are bent at substantially right angles on both left and right sides of the central portion. On both sides, mounting portions are provided that are inserted into step mounting holes formed in the wall portion. The attachment portion is provided from each of the tip portions on both sides to a predetermined position determined according to the thickness of the wall portion. In addition, a locked portion is formed at a position on both sides and adjacent to the mounting portion (a position far from the tip). The cover ring is attached to each of both sides of the step and has, for example, a generally donut shape. The through-hole provided in the center part of the cover ring is formed with a locking part that is locked to the locked part. When attaching the step to the attachment hole, the cover ring is fitted to both sides of the step in advance, and the cover ring is moved in the direction of the tip (attachment direction) after installation (pushing in or screwing in). . Accordingly, the locked portion and the locking portion are locked, and the step mounting hole is closed or covered by the cover ring.
Further, by pushing the cover ring in the direction of the attachment portion, the projection on the cover ring side is locked to the concave groove on the step side. Further, the front end of the cover ring in the insertion direction comes into contact with the sleeve in the mounting hole. At this time, the cover ring does not come into contact with the inner wall surface of the manhole and a part thereof is fitted into the mounting hole on the inner wall surface side of the manhole. As a result, the mounting strength of the step can be increased by the cover ring made of a rigid member, and in particular, the backlash of the opening portion of the mounting hole on the inner wall surface side of the manhole can be suppressed.

According to a second aspect of the present invention, there is provided the step mounting structure according to the first aspect, wherein a concave portion is formed on the outer peripheral surface of the step mounting portion .

The concave portion of the attachment portion of the step functions as a stopper for removing a bag-like sponge containing an adhesive resin, for example.

According to the step mounting structure of the present invention, the cover on the inner wall surface of the manhole can be covered with the cover ring by pushing the cover ring attached around the step toward the tip of the step inserted and fixed in the mounting hole. it can. Further, the step is fixed by engaging the engaging portion of the cover ring with the locked portion of the step, and a part of the cover ring can be fitted into the attachment hole to increase the attachment strength of the step. Further, the gap between the inner wall surface of the manhole can be filled and intimately filled with the filler interposed in the covering surface.

Embodiments of a step mounting structure according to the present invention will be described below with reference to the accompanying drawings. However, the form shown in FIGS. 1 and 2 corresponds to the invention described in the scope of claims of the present applicant.
The form shown in FIGS. 1 and 2 is a structure using a cover ring in which step 2 is attached and fixed to the wall 1 of the manhole using an adhesive, and then a part of the cover ring is fitted in the attachment hole. is there.
FIG. 1 is a partial cross-sectional view showing a state in which a step is attached to a peripheral wall (wall portion) of a manhole. As shown in FIG. 2A, a mounting hole 3 for mounting the step 2 is formed in the wall portion 1 of the manhole made of concrete. The mounting hole 3 is formed from the inner wall surface 1a side of the manhole, has a circular shape, and includes two hole portions 3c and 3d having different diameters, and an annular step 4 is formed at the boundary. The mounting hole 3 does not necessarily pass through the wall 1 to the outer wall surface 1b side, and its form may be determined according to the thickness of the wall 1.

  FIG. 2B shows a bottomed cylindrical sleeve 30 inserted into the mounting hole 3. One end (front end side) of the sleeve 30 is closed by the bottom, and a plurality of openings 32 are provided in the peripheral wall. At the other end (base side) of the sleeve 30, a flange 31 is provided that sits on the annular step 4 of the mounting hole 3 when the sleeve 30 is inserted into the mounting hole 3. Accordingly, the diameter of the hole portion 3d is such that the flange 31 can be inserted, and is formed to have a diameter substantially the same as the diameter of the flange 31.

  FIG. 2 (c) shows the side 2 b of step 2. The side portion 2b is provided with an attachment portion 9 to be inserted and attached to the attachment hole 3 formed in the manhole wall portion 1, and a locked portion (concave portion, concave groove portion) 37 at a position adjacent to the attachment portion 9. ing. A plurality of concave portions 33 extending in the circumferential direction are formed in the attachment portion 9. In this form, a plurality of concave grooves 38 are formed in the locked portion 37 in parallel with the outer periphery. However, the number of the grooves 38 should be at least as large as the number of protrusions (described later in FIG. 2D).

  FIG. 2 (d) shows a cross-sectional view of the cover ring 8 attached to the side part 2 b of Step 2. The cover ring 8 has, for example, a donut shape, a through hole is formed at the center, and a locking portion (a convex portion or a protruding portion) that locks with the locked portion of Step 2 on the peripheral wall of the through hole. 36 is formed. The cover ring 8 is composed of a rigid member such as hard plastic. The diameter of the cover ring 8 is formed to be approximately the same as the diameter of the hole portion 3d, and is mounted around the side portion 2b. When the cover ring 8 is pushed in the direction of the attachment portion 9 in step 2, the projection portion 36 is engaged with the concave groove portion 37 (any concave groove), and a part (tip portion) of the cover ring 8 is the hole portion 3d. It has a structure that fits inside.

  In order to attach step 2 to the wall 1 of the manhole in the form of FIGS. 1 and 2 described above, first, the sleeve 30 is inserted into the attachment hole 3 from the inner wall 1a side of the manhole. The sleeve 30 is pushed in until the flange 31 is in contact with the annular step 4 of the mounting hole 3. Next, the attachment portion 9 of step 2 is inserted into the attachment hole 3 (the sleeve 30 inserted into the attachment hole 3). At this time, the cover ring 8 is preliminarily screwed into the male screw portion 10 of the attachment portion 9 and temporarily held. Keep it. Then, a bag-like sponge or the like containing an adhesive resin made of an epoxy resin or the like (not shown) may be attached to the attachment portion 9 and inserted into the attachment hole 3. The concave portion 33 of the attachment portion 9 functions as a retaining agent for the sponge. The adhesive 21 that protrudes from the opening of the peripheral wall of the sleeve to the outside of the sleeve reaches the inner wall surface of the mounting hole 3, and the mounting portion 9 in step 2 is securely bonded to the mounting hole 3.

  By pressing the cover ring 8 along the side 2b after the adhesive 21 is solidified, the cover ring 8 moves without coming into contact with the inner wall surface 1a of the manhole, and the protrusion 36 of the cover ring 8 is recessed in step 2. The cover ring 8 is engaged with the groove portion 37, and a part of the cover ring 8 is fitted into the attachment hole 3 (in the hole portion 3d). When further pushed, the front surface 34 of the cover ring 8 comes into contact with the flange surface 35 of the sleeve 30.

  As a result, the manhole inner wall surface side opening portion of the mounting hole 3 (opening portion of the hole portion 3 d) is completely closed by the cover ring 8. Since the opening portion is closed in a state where a part of the cover ring 8 is fitted in the mounting hole 3, the opening portion can be formed without any gap regardless of the size of the manhole, that is, without being affected by the shape of the inner wall surface 1a. Can be closed. Further, since the cover ring 8 is made of a rigid member, the cover ring 8 itself can suppress the looseness and backlash of the step 2 at the inner wall surface side opening and increase the attachment strength.

  FIG. 3 shows another form of the step mounting structure. This form is the same as the form shown in FIG. 1 in that an adhesive is used, but has a different structure in that the engagement between the cover ring 8 and the side part 2b is performed by screw means.

  FIG. 4 shows the structure of each part before being attached and fixed. FIG. 4A shows the mounting hole 3 in step 2 formed in the wall 1 of the manhole, which is the same as the mounting hole shown in FIG. FIG. 4B shows a bottomed cylindrical sleeve 30 inserted into the mounting hole 3 and is the same as the sleeve shown in FIG.

  FIG. 4C shows the side portion 2 b of Step 2. The side portion 2b is provided with an attachment portion 9 that is inserted and attached to an attachment hole 3 formed in the manhole wall portion 1, and a male screw portion 10 that is provided at a position adjacent to the attachment portion 9 and has a screw formed on the outer periphery. It has been. The attachment portion 9 is formed with a plurality of concave portions 33 extending in the circumferential direction.

  FIG. 4D shows a cross-sectional view of the cover ring 8 that is attached to the side portion 2 b of Step 2. The cover ring 8 has, for example, a donut shape, a through hole is formed at the center, and a female screw portion 12 that is screwed into the male screw portion 10 of Step 2 is formed on the peripheral wall of the through hole. The cover ring 8 is composed of a rigid member such as hard plastic. The diameter of the cover ring 8 is formed to be approximately the same as the diameter of the hole portion 3d. When the cover ring 8 is screwed by screwing the female screw portion 12 into the male screw portion 10 in step 2, the cover ring 8 is covered. A part (tip portion) of the ring 8 is structured to fit into the hole portion 3d.

  3 and 4 described above, in order to attach step 2 to the wall 1 of the manhole, first, the sleeve 30 is inserted into the attachment hole 3 from the inner wall 1a side of the manhole. The sleeve 30 is pushed in until the flange 31 is in contact with the annular step 4 of the mounting hole 3. Next, the attachment portion 9 of step 2 is inserted into the attachment hole 3 (the sleeve 30 inserted into the attachment hole 3). At this time, the cover ring 8 is preliminarily screwed into the male screw portion 10 of the attachment portion 9 and temporarily held. Keep it. Then, a bag-like sponge or the like containing an adhesive resin made of an epoxy resin or the like (not shown) may be attached to the attachment portion 9 and inserted into the attachment hole 3. The concave portion 33 of the attachment portion 9 functions as a retaining agent for the sponge. The adhesive 21 that protrudes from the opening of the peripheral wall of the sleeve to the outside of the sleeve reaches the inner wall surface of the mounting hole 3, and the mounting portion 9 in step 2 is securely bonded to the mounting hole 3.

  At this time, the male screw portion 10 is disposed so as to protrude from the inside of the manhole (inside the inner wall surface 1a), that is, from the mounting hole 3 into the manhole. By screwing the female threaded portion 12 of the cover ring 8 into the male threaded portion 10 after the adhesive 21 is solidified, a part of the cover ring 8 is fitted in the mounting hole 3 (in the hole portion 3d), and the front surface 34 of the cover ring 8 is It contacts the flange surface 35 of the sleeve 30. The pressure contact strength to the flange surface 35 can be easily adjusted by the screwing amount of the cover ring 8.

  As a result, the manhole inner wall surface side opening portion of the mounting hole 3 (opening portion of the hole portion 3 d) is completely closed by the cover ring 8. Since the opening portion is closed in a state where a part of the cover ring 8 is fitted in the mounting hole 3, the opening portion can be formed without any gap regardless of the size of the manhole, that is, without being affected by the shape of the inner wall surface 1a. Can be closed. Further, since the cover ring 8 is made of a rigid member, the cover ring 8 itself can suppress the looseness and backlash of the step 2 at the inner wall surface side opening and increase the attachment strength. Moreover, since it has the structure which screws together, it is easy to temporarily hold the cover ring 8 in the position away from the inner wall surface 1a until the adhesive agent 21 hardens | cures, and its working efficiency is also good. .

5 and 6 show another form of the step mounting structure. This form is similar to the form shown in FIG. 3 in that an adhesive is used, but has a different structure in that the cover ring 8 is placed in pressure contact with the inner wall surface 1a.
FIG. 5 is a partial cross-sectional view showing a state in which a step is attached to the peripheral wall (wall portion) of the manhole. A mounting hole 3 for mounting the step 2 is formed in the wall 1 of the manhole. The mounting hole 3 is formed from the inner wall surface 1a side of the manhole, has a circular shape, and has a depth that does not penetrate to the outer wall surface 1b side of the manhole.

  The mounting hole 3 is filled with the adhesive 21, and the mounting portion 9 of step 2 is inserted therein. At this time, in consideration of leakage of the adhesive 21 from the mounting hole 3, a bag-like sponge containing an adhesive resin made of epoxy resin or the like (not shown) is mounted on the mounting portion 9 and then mounted. It may be inserted into the hole 3. Note that the bonding method in step 2 is not limited to this form, and for example, the form described in FIGS. 1 and 3 may be used.

  FIG. 6A shows a part of Step 2. Step 2 has, for example, a generally U-shape as a whole (an example is shown in FIG. 8). Step 2 shown in FIG. 6A includes a central portion 2a that serves as a footrest portion or a gripping portion for the operator, and both side portions 6b that are bent from the central portion 2a (one side portion is shown in the figure). Are). The side portion 2b is provided with an attachment portion 9 that is inserted and attached to an attachment hole 3 formed in the manhole wall portion 1, and a male screw portion 10 that is provided at a position adjacent to the attachment portion 9 and has a screw formed on the outer periphery. It has been.

  6B is a sectional view of the cover ring 8 attached to the side portion 2b of Step 2, and FIG. 6C is a perspective view of the cover ring 8. As shown in FIG. The cover ring 8 has, for example, a donut shape, a through hole is formed at the center, and a female screw portion 12 that is screwed into the male screw portion 10 of Step 2 is formed on the peripheral wall of the through hole. The cover ring 8 is configured in a form made of a rigid member such as hard plastic, or in a form made of elastic plastic or the like.

  In order to attach step 2 to the wall 1 of the manhole in the form of FIGS. 5 and 6 described above, first, the cover ring 8 is first screwed into the male thread 10 of the attachment 9 and temporarily held. Then, the attachment hole 3 formed in the wall portion 1 of the manhole is filled with the adhesive 21, and the attachment portion 9 in step 2 is inserted into the attachment hole 3 in this state. At this time, the male screw portion 10 is disposed so as to protrude from the inside of the manhole (inside the inner wall surface 1a), that is, from the mounting hole 3 into the manhole. After the adhesive 21 is solidified, the cover screw 8 is pressed against the inner wall surface 1a by screwing the female screw part 12 of the cover ring 8 into the male screw part 10. The pressure contact strength to the inner wall surface 1a can be easily adjusted by the screwing amount of the cover ring 8.

  As a result, the cover ring 8 covers the manhole inner wall surface side opening portion of the mounting hole 3. The chip end chipping of the opening on the inner wall surface that occurs when the mounting hole 3 is formed is covered by the cover ring 8. Further, when the cover ring 8 made of a rigid member is used, the cover ring 8 itself can suppress the looseness and backlash of the step 2 at the inner wall surface side opening and increase the attachment strength. When the cover ring 8 made of an elastic material is used, the cover ring 8 is deformed by being pressed against the inner wall surface 1a, so that the inner wall surface 1a is not necessarily flat (for example, curved surface). The cover ring 8 is in close contact with the inner wall surface 1a. Moreover, since it has the structure which screws together, it is easy to temporarily hold the cover ring 8 in the position away from the inner wall surface 1a until the adhesive agent 21 hardens | cures, and its working efficiency is also good. .

  In addition, the form of the attachment hole 3 formed in the wall part 1 when using the adhesive 21 may be formed so as to penetrate to the outer wall surface 1b side (illustration is omitted). In that case, a bottomed cylindrical sleeve may be inserted into the mounting hole 3, and the mounting portion 9 of the step in which the sponge containing the adhesive 21 is mounted may be inserted therein. The front end side of the sleeve is closed by the bottom (bottomed cylinder), and a plurality of openings are provided in the peripheral wall of the sleeve. The bottom of the sleeve can reliably close the outer wall surface 1b side of the through hole (mounting hole 3) of the wall portion 1 and can prevent the ingress of groundwater into the mounting hole 3. Further, since the adhesive 21 that protrudes from the opening of the peripheral wall of the sleeve reaches the inner wall surface of the mounting hole 3, the mounting portion 9 in step 2 is securely bonded to the mounting hole 3.

  According to this structure, when step 2 is newly attached to an already installed manhole, or when replacing old step 2, only the work performed from the inner wall surface 1a side of the manhole is completed, so there is an advantage in workability. Have.

FIG. 7 shows another form of the step mounting structure. This form has a structure in which the nut is tightened and fixed from the outer wall surface 1b side of the manhole.
As shown in FIG. 7A, a mounting hole 3 for mounting the step 2 is formed in the wall 1 of the manhole so as to penetrate the wall 1. The mounting hole 3 has a circular shape and is composed of two hole portions 3a and 3b having different diameters, and an annular step 4 is formed at the boundary.

  The mounting portion 9 of Step 2 is inserted into the mounting hole 3 from the inner wall surface 1a side of the manhole, and the nut 5 is screwed through the packing 6 and the washer 7 from the outer wall surface 1b side of the manhole. On the other hand, the cover ring 8 screwed into the step 2 is mounted on the inner wall surface 1a side of the manhole as in the embodiment of FIGS.

  FIG. 7B shows a part of Step 2. This form has a structure in which the nut 5 is screwed from the outer wall surface 1b side (see FIG. 7A). Compared with the form of FIGS. The difference is that the portion 11 is formed. The structure of the other steps and the cover ring 8 are the same as those shown in FIGS.

  7A and 7B, in order to attach Step 2 to the wall 1 of the manhole, first, the cover ring 8 is first screwed into the male thread 10 of the attachment 9 and temporarily held. . In this state, the attachment portion 9 of step 2 is inserted into the attachment hole 3 formed in the wall portion 1 of the manhole, the nut 5 is screwed into the screw portion 11 via the packing 6 and the washer 7, and the packing 6 and the washer 7 are attached. It is seated on the annular step 4. At this time, the nut 5 is screwed to such a depth that the tip of the attachment portion 9 does not protrude from the attachment hole 3 (hole portion 3a) to the outer wall surface 1b of the manhole. At this time, the male screw portion 10 is disposed so as to protrude from the inside of the manhole (inside the inner wall surface 1a), that is, from the mounting hole 3 into the manhole. Thereafter, the cover ring 8 is screwed (the female screw portion 12 is screwed into the male screw portion 10), and the cover ring surface 8a is pressed against the inner wall surface 1a of the manhole. The pressure contact strength to the inner wall surface 1a can be easily adjusted by the screwing amount of the cover ring 8.

  As a result, the cover ring 8 covers the manhole inner wall surface side opening portion of the mounting hole 3. The chip end chipping of the opening on the inner wall surface that occurs when the mounting hole 3 is formed is covered by the cover ring 8. 5 and 6, the cover ring 8 is made of a rigid member or an elastic member. When the cover ring 8 made of a rigid member is used, the cover ring 8 The step 2 is securely fixed to the wall 1 of the manhole by the cover ring 8 and the nut 5 supported from the outside. In particular, the cover ring 8 can suppress the looseness and backlash of the step 2 at the inner wall surface side opening and can increase the attachment strength. Further, when the cover ring 8 made of an elastic material is used, the cover ring 8 is deformed according to the shape of the inner wall surface 1a due to the pressure contact with the inner wall surface 1a and is in close contact with the inner wall surface 1a.

  FIGS. 8A and 8B show step 2 attached to the manhole wall 1 having a different shape. (A) is step 2 attached to the wall portion 1 of the circular manhole, that is, step 2 attached to the curved inner wall surface 1a ′, and (b) is a square manhole, ie, a planar shape. It is step 2 attached to the inner wall surface 1a. The surface of the cover ring 8 is formed corresponding to the shape of the inner wall surfaces 1a, 1a 'so as to be in close contact with the inner wall surfaces 1a, 1a' to which the step 2 is attached. When the inner wall surfaces 1a and 1a ′ are curved, the surface of the cover ring 8 is formed in a curved shape so as to be in close contact with the curved surface, and when the inner wall surfaces 1a and 1a ′ are planar. The surface of the cover ring 8 is formed in a flat shape so as to be in close contact with the flat surface. In addition, although the form shown to Fig.8 (a), (b) is a thing of the structure which carries out nut fastening from the outer wall surface 1b, 1b 'side of a manhole, it is not limited to this, For example, the adhesive agent 21 is used. It may have a structure of mounting and fixing.

FIGS. 9A, 9B, and 9C show cover rings having different shapes.
(A) is a form in which the cover ring surfaces (upper and lower surfaces in the figure) 8a and 8b are formed in a flat shape, for example, on a flat wall surface such as a manhole having a square opening section. Used for attached steps. The cover ring 2 used in FIGS. 5, 7, and 8 (b) has the same form. (B) is a form in which the surface 8a′8b ′ of the cover ring has an inclination angle θ, and is used for a step attached to an inclined inner wall surface (not shown). . The inclination angle θ is set to the same angle as the inclination angle of the inner wall surface so as to be in close contact with the inner wall surface. (C) is a form in which the surfaces 8a ″ and 8b ″ of the cover ring are formed in a curved shape, and used for a step of attaching to a curved inner wall surface such as a manhole having a circular opening section, for example. Is done. The cover ring 2 used in FIG. 8A has the same form. However, in any form of the cover ring, the female thread portion 12 is formed along the axial direction of the side portion 2b of the step to be mounted. 9B and 9C, the peripheral portion excluding the female screw portion 12 is formed of an elastic material.

FIG. 10 shows an embodiment in which a filler is provided on the surface of the cover ring 8.
The filler 25 is provided on the surface that contacts the inner wall surface of the manhole when the cover ring 8 is attached to the step. Further, a material made of a viscoelastic material that deforms when an external force is applied, that is, when the cover ring 8 is screwed into pressure contact with the inner wall surface, such as butyl rubber or putty, is used. The filler 25 crushed by screwing the cover ring 8 fills a recess such as a chipped end portion generated in the opening on the inner wall surface side of the mounting hole. As a result, the cover ring 8 and the inner wall surface are in close contact with each other without a gap.

It is a partial sectional view showing one form of a step attachment structure concerning the present invention. (A) is sectional drawing which shows one form of the step attachment hole formed in the manhole. (B) is a figure which shows one form of the sleeve inserted in an attachment hole. (C) is a figure which shows one form of a step side part. (D) is sectional drawing which shows one form of a cover ring. It is a partial cross section figure which shows another one form of the step attachment structure which concerns on this invention. (A) is sectional drawing which shows one form of the step attachment hole formed in the manhole. (B) is a figure which shows one form of the sleeve inserted in an attachment hole. (C) is a figure which shows one form of a step side part. (D) is sectional drawing which shows one form of a cover ring. It is a partial sectional view showing one form of a step attachment structure concerning the present invention. (A) is a top view showing the side part from the center part of the step of the step attachment structure concerning this invention. (B) is sectional drawing showing the cover ring with which the side part of a step is mounted | worn. (C) is a perspective view of a cover ring. (A) is a partial cross section figure which shows another one form of the step attachment structure which concerns on this invention. (B) is the top view showing the side part from the center part of the step shown to (a), and sectional drawing showing the cover ring with which the side part of a step is mounted | worn. (A) is a figure showing one form of a step attached to a manhole. (B) is a figure which shows one form of the step attached to the manhole which has another shape. (A) is sectional drawing which shows one form of a cover ring. (B) is sectional drawing which shows the cover ring of another form. (C) is sectional drawing which shows the cover ring of another form. It is sectional drawing which shows one form of the cover ring which provided the filler.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wall part 1a Inner wall surface 1b Outer wall surface 2 Step 2a Center part 2b Side part 3 Attachment hole 3a, 3b, 3c, 3d Hole part 4 Annular step part 5 Nut 8 Cover ring 9 Attachment part 10 Male thread part 12 Female thread part 21 Adhesive 25 Filler 30 Sleeve 36 Locking part (convex part, protruding part)
37 Locked part (concave part, concave groove part)

Claims (2)

In the step mounting structure in which a mounting hole is provided in the wall portion of the concrete manhole and a step is attached to the mounting hole.
An annular step provided on the inner wall surface of the mounting hole;
A sleeve having a flange inserted into the mounting hole and having a front end side closed by a bottom and provided on a peripheral wall and a flange seated on the annular step;
An adhesive filled through each opening of the sleeve between the mounting portion of the step and the mounting hole;
A locked portion provided on a peripheral surface of a portion adjacent to the mounting portion of the step ;
A cover ring that is mounted and arranged around the step, has a locking portion that engages with the locked portion, and closes the mounting hole of the wall portion ;
The locked portion is composed of a concave groove portion, and the locking portion is composed of a protrusion,
The cover ring is formed of a rigid member, and when the projection is engaged with the concave groove portion of the step by being pushed toward the attachment portion of the step, the front surface of the cover ring contacts the flange of the sleeve, and the cover A step mounting structure in which a ring closes a mounting hole on the inner wall surface of the manhole and a part of the ring is fitted into the mounting hole . The step mounting structure according to claim 1, wherein a concave portion is formed on an outer peripheral surface of the step mounting portion .

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