JP4456022B2 - Manhole cover - Google Patents

Description

  The present invention relates to an iron lid for manholes, and more particularly to an iron lid for manholes that can reliably prevent the snow removal plate from being caught on the iron lid during snow removal work by a snowplow.

  As shown in FIG. 5, the manhole iron cover 11 is fitted into a receiving frame 13 embedded in a road 12. The road surface 12A, the upper surface 13A of the receiving frame 13 and the upper surface 11A of the iron lid 11 are constructed so as to be at the same level.

  However, when the road surface 12A descends due to ground subsidence or the like, the upper portion of the receiving frame 13 is exposed from the road surface 12A. This phenomenon occurs particularly in snowfall areas where snow melting pipes are buried under the road surface and groundwater is flowing through the pipes, and there are the following problems.

  When the upper portion of the receiving frame 13 is exposed from the road surface 12A, the snow removal plate is caught by the exposed receiving frame 13 during snow removal work by the snowplow, causing damage to the receiving frame 13 and the iron lid 11.

  Therefore, as shown in FIG. 5, in order to escape the snow removal plate, the upper corner portion of the receiving frame 13 is formed in an arc shape to prevent the snow removal plate from being caught on the exposed receiving frame 13.

  By the way, the manhole iron cover 11 is raised or obliquely inserted into the receiving frame 13 due to the generation of rust or sand or the like caused by handling, or the occurrence of rust or sand or the like caused by handling. Even without this, the iron lid 11 may be fitted into the receiving frame 13 at an angle.

  Thus, even if the iron lid 11 is raised relative to the receiving frame 13 or fitted obliquely, the same problem as in the case of the receiving frame 13 occurs.

  Therefore, an iron lid for manhole that solves this problem is disclosed in Japanese Patent No. 2686583 (Patent Document 1). As shown in FIG. 6, the conventional iron lid 14 is formed by cutting the upper corner portion under certain conditions (shown as an outer peripheral end cut portion in the figure) to form an inclined surface 14A. That is, the conventional iron lid 14 is a manhole iron lid that is fitted into the receiving frame 15 so that the upper surface thereof is at the same height as or lower than the upper surface of the receiving frame 15, and the upper corner portion of the iron lid 14 is An inclined surface 14A is formed at the upper corner portion by inclining downward from the outer peripheral end by 1.5 mm or more toward the inner side to the outer side and reaching from the outer peripheral end to the lower side by 1.5 mm or more along the outer peripheral surface. .

Japanese Patent No. 2686583

  According to the conventional iron lid 14, the inclined surface 14 </ b> A is formed at the upper corner portion of the iron lid 14, so even if the iron lid 14 is fitted into the receiving frame 15 so as to protrude from the receiving frame 15, FIG. As shown, the snow removal plate 16 can escape and the snow removal plate 16 can be prevented from being caught on the iron lid 14.

  However, even if the snow removal plate 16 escapes, as shown in FIG. 7, the iron lid 14 remains obliquely fitted into the receiving frame 15 and causes vibration and noise when the vehicle travels. It becomes. The phenomenon in which the iron lid 14 fits obliquely into the receiving frame 15 is further promoted by the vehicle traveling on the iron lid 14, and the iron lid 14 becomes further oblique.

  Therefore, even if the iron lid protrudes from the receiving frame, the object of the present invention is that the iron lid is pushed down by the snow removing plate and completely fits in the receiving frame, and as a result, the snow removing plate is reliably caught on the iron lid. An object of the present invention is to provide a manhole cover that can be prevented.

  The present invention has been made to achieve the above object, and is characterized by the following.

  The invention according to claim 1 is characterized in that it has a groove formed in at least one part of the upper corner part, and hemispherical protrusions provided in the groove at intervals along the longitudinal direction thereof. Is.

  The invention according to claim 2 is characterized in that, in the invention according to claim 1, the height of the protrusion is equal to the upper surface level of the iron lid.

  The invention according to claim 3 is characterized in that, in the invention according to claim 1 or 2, the height of the protrusion is 2 to 5 mm.

  The invention described in claim 4 is characterized in that, in the invention described in any one of claims 1 to 3, the protrusions are formed at intervals of 10 to 20 mm.

  According to the present invention, a groove is formed over the entire circumference of the upper corner of the iron lid, and the iron lid protrudes from the receiving frame by providing the groove with a hemispherical protrusion spaced along the longitudinal direction. However, since the snow removing plate hits the hemisphere and a force is applied to the iron lid to push it down into the receiving frame, it is possible to reliably prevent the snow removing plate from being caught on the iron lid. And since the said protrusion is formed in hemispherical shape, the said effect | action arises from which direction a snow removal board contacts a protrusion.

  Next, an embodiment of the iron cover for manholes of the present invention will be described with reference to the drawings. This example is a circular iron lid, but may be a square iron lid.

  1 is a partial plan view showing an iron cover for manholes according to the present invention, FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1, and FIG. 3 is a cross-sectional view showing a state in which a snow removal plate hits a hemispherical protrusion FIG. 4 is a cross-sectional view showing a state where the iron lid is pushed down by the snow removal plate.

  As shown in FIG. 1 to FIG. 4, the manhole iron cover 1 of the present invention has a groove 1 </ b> A formed in at least one part of the upper corner part and a groove 1 </ b> A spaced along the longitudinal direction thereof. It is comprised from what has the provided hemispherical protrusion 1B. The reason why the groove 1A is formed in at least one part is that the groove 1A is not formed in the upper corner portion where the problem of strength reduction occurs when the groove 1A is formed. The height of the hemispherical protrusion 1B is equal to the upper surface level of the iron lid 1, and a height of 2 to 5 mm is preferable in order to bring about the effects of the present invention. The distance between adjacent hemispherical protrusions 1B is preferably formed at an interval of 10 to 20 mm in order to bring about the effects of the present invention. The hemispherical protrusion 1B may be a protrusion having a curved surface, even if it is not strictly hemispherical.

  As shown in FIG. 3, the groove 1A is formed in at least one part of the upper corner portion of the iron lid 1 and the hemispherical protrusion 1B is provided in the groove 1A at intervals along the longitudinal direction. Even if the iron lid 1 protrudes from the receiving frame 2, if the snow removal plate 16 hits the hemispherical protrusion 1B, the snow removal plate 16 advances while sliding on the hemispherical protrusion 1B as shown in FIG. As a result, a force (the direction of the force is indicated by an arrow in the figure) for pushing down the iron lid 1 into the receiving frame acts. Since the protrusion 1B is formed in a spherical shape, the pressing force is generated regardless of the direction in which the snow removal plate 16 hits the protrusion 1B. As a result, the iron lid 1 is properly fitted in the receiving frame 2, and the snow removal plate 16 is reliably prevented from being caught on the iron lid 1.

  As described above, according to the present invention, a groove is formed over the entire upper corner of the iron lid, and a hemispherical protrusion is provided in the groove at intervals along the longitudinal direction thereof. Even if the lid protrudes from the receiving frame, the snow removal plate hits the hemispherical protrusion, and a force is applied to the iron lid to push it down into the receiving frame. As a result, the snow removal plate can be reliably prevented from being caught on the iron lid.

It is a fragmentary top view which shows the iron cover for manholes of this invention. It is the sectional view on the AA line of FIG. It is sectional drawing which shows the state which the snow-removal board contacted the hemispherical protrusion. It is sectional drawing which shows the state by which the iron cover was pushed down by the snow removal board. It is sectional drawing which shows the iron cover engage | inserted in the receiving frame. It is sectional drawing which shows the state of escape of the snow removal board by the conventional iron cover. It is sectional drawing which shows the state in which a pushing down force does not act on an iron lid by the escape of a snow removal board in a conventional iron lid.

Explanation of symbols

1: Iron lid 1A: Groove 1B: Hemispherical protrusion 2: Receiving frame 11: Iron lid 11A: Upper surface 12: Road 12A: Road surface 13: Receiving frame 13A: Upper surface 14: Conventional iron lid 14A: Inclined surface 14B: Side surface 15: Receiving frame 16 : Snow removal board

Claims (4)

  An iron lid for a manhole, comprising: a groove formed in at least one part of an upper corner portion; and a hemispherical protrusion provided in the groove at an interval along a longitudinal direction thereof.   The manhole iron cover according to claim 1, wherein a height of the protrusion is equal to an upper surface level of the iron cover.   The manhole iron cover according to claim 1 or 2, wherein a height of the protrusion is 2 to 5 mm.   4. The manhole iron cover according to claim 1, wherein the protrusions are formed at intervals of 10 to 20 mm. 5.

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