JP2010037935A - Manhole cover - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manhole cover having a required strength, lower in weight and cost than conventional manholes, and usable for arterial roads. <P>SOLUTION: Parallel cross-shaped reinforcement ribs 7 are formed on the lower surface of the plate part 6 of a cast manhole cover body 5. A surrounding part 8 is formed at the center of the reinforcement ribs 7. Auxiliary ribs 9, 9 the lower edges of which have a height h lower by approximately half the height H of the surrounding part 8 extend radially from the center of a plate part 6 in an X-shape on the inside of the surrounding part 8. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a manhole cover provided with reinforcing ribs.

  As a manhole cover, a plate-shaped one made of a metal material such as ductile cast iron is generally used. However, a reinforcing rib is provided on the back surface in order to reduce the weight of the manhole cover that maintains the required mechanical strength.

  And the manhole cover used for roads with heavy traffic, such as national roads, prefectural roads, and main roads, has the same strength and durability as manhole covers used for other general roads with relatively low traffic. Naturally, it is required to have a high mechanical strength, and two types of inspection standards are used for its mechanical strength, which are used for general roads and where there is a lot of traffic.

  For example, in the case of a manhole cover with a diameter of 634 mm, when a load of 120 kN is applied to the load plate (200 mm × 500 mm) of a destructive inspection machine with a manhole cover used on a general road with little traffic, the deflection is 2.2 mm or less. The standard is that the residual deflection is 0.1 mm or less and does not break with a load of 400 kN (hereinafter referred to as standard 1). In addition, with a manhole cover of the same diameter used for arterial roads, when a load of 210 kN is applied with a loading plate (200 mm × 500 mm), the deflection is 2.2 mm or less, the residual deflection is 0.1 mm or less, and 700 kN The standard (hereinafter referred to as “Criteria 2”) is that it is not broken by a load.

  1 and 2 are a bottom view of a conventional manhole cover having a diameter of 634 mm and a cross-sectional view taken along line A-A of the figure. 1 is a metal manhole cover body, 2 is a plate portion of the manhole cover body 1, and 3 is the plate portion. Reinforcing ribs provided in the form of a cross-beam on the back surface of 2, 4 is an enclosure portion formed at the center of the reinforcing rib 3, T is the thickness of the plate portion 2, S is the width of the reinforcing rib, and H is the Shows the height.

  Table 1 shows the results when load inspection is performed on the manhole covers M1 and M2 satisfying the above criteria 1 and 2, respectively, according to the criteria 2. The thickness and width of T and S are smaller than M2, and the enclosure portion The M2 manhole cover with a low height of 4 cannot satisfy the standard 2. That is, it cannot be used as a manhole cover for roads with heavy traffic.

  As can be seen from Table 1, the manhole cover M2 that satisfies the standard 2 used for the above-mentioned main roads, etc. is made thicker than the manhole cover M1 that is used for other purposes in order to satisfy the standard, Since the height H is increased, it is inevitably heavier than the manhole cover M1, and the amount of material used for the manhole cover is increased, resulting in higher costs.

Design Registration No. 992775

  Therefore, an object of the present invention is to provide a manhole cover that can be used on a main road or the like that satisfies the required strength and is lighter in weight and less expensive than a conventional manhole cover.

  SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. The invention according to claim 1 is characterized in that a reinforcing rib is provided on the back surface of the plate portion and a polygonal or annular enclosure is formed at the center of the back surface. The manhole cover is characterized in that auxiliary ribs having a lower edge lower than the height of the surrounding portion are provided radially in the surrounding portion.

  According to the second aspect of the present invention, reinforcing ribs are provided on the back surface of the plate portion, and a polygonal or annular surrounding portion is formed at the center of the back surface, and auxiliary ribs having an arch shape at the lower edge are radially formed in the surrounding portion. It is a manhole cover provided.

  According to the third aspect of the present invention, a reinforcing rib is provided on the back surface of the plate portion, a polygonal or annular surrounding portion is formed at the center of the back surface, and a curved auxiliary rib is provided in a bowl shape in the surrounding portion. It is a characteristic manhole cover.

  According to a fourth aspect of the present invention, in the manhole cover according to the first or third aspect, the lower edge of the auxiliary rib has an arch shape.

  According to a fifth aspect of the present invention, in the manhole cover according to any one of the first to fourth aspects, the crossover portion of the auxiliary rib provided in the polygonal or annular enclosure provided in the center of the back surface of the plate portion. The manhole cover is characterized in that a strength-enhancing meat portion is provided integrally with the auxiliary rib and the plate portion.

  According to a sixth aspect of the present invention, in the manhole cover according to any one of the first to fifth aspects, the back surface of the plate portion outside the enclosure portion has a lower height than other reinforcing ribs or auxiliary ribs. It is a manhole cover provided with a rib.

  According to a seventh aspect of the present invention, in the manhole cover according to any one of the first to sixth aspects, the strength is enhanced at the intersection of the polygonal or annular surrounding portion provided at the center of the back surface of the plate portion and the reinforcing rib. The manhole cover is characterized in that a fleshing portion is provided integrally with the reinforcing rib, the enclosure portion and the plate portion.

  The present invention requires strength by forming an encircling portion at the most heavily loaded central portion of the manhole cover, and providing auxiliary ribs radially in the encircling portion, or providing curved auxiliary ribs in a bowl shape. The strength of the central part is increased, and as a result, the thickness of the plate part of the manhole cover can be reduced, and the required standard can be satisfied even if the height of the surrounding part is reduced. Since the material can be reduced and the weight of the manhole cover can be reduced, the transportation and handling of the manhole cover, especially the opening / closing operation can be facilitated.

  Further, by forming the lower edge of the auxiliary rib in an arch shape, it is possible to further reduce the weight while maintaining the load strength, and further, by curving the auxiliary rib, the portion provided with the reinforcing rib This is expected to have the effect of reducing the noise generated when passing through the vehicle by making the vibration characteristics different.

  Furthermore, the strength at the center of the plate portion is increased by integrally providing the reinforcing rib and the plate portion at the crossing portion of the auxiliary rib provided in the enclosed portion, and the outer side of the enclosed portion. By providing a reinforcing rib with a lower height than other reinforcing ribs or auxiliary ribs on the back side of the plate part, the strength of the plate part outside the enclosure part can be increased, and the thickness of the plate part can be reduced as a result. Thus, the amount of metal material used for the lid can be reduced, and a lightweight, low-cost and high-strength manhole cover can be provided.

The bottom view which shows the conventional manhole cover. AA sectional view taken on the line AA of FIG. The bottom view of the 1st example of the present invention. BB sectional drawing of FIG. The bottom view of the 2nd example of the present invention. The CC sectional view taken on the line of FIG. The bottom view of the 3rd example of the present invention. The DD sectional view taken on the line of FIG. The bottom view of the 4th example of the present invention. EE sectional view taken on the line of FIG. The bottom view of the 5th example of the present invention. FF sectional view taken on the line of FIG. The bottom view of the 6th example of the present invention. GG sectional view taken on the line of FIG. The bottom view of the 7th example of the present invention. The HH sectional view taken on the line of FIG. The bottom view of the 8th example of the present invention. The II sectional view taken on the line of FIG. FIG. 18 is a partial cross-sectional view taken along line JJ in FIG. 17.

  3 and 4 show a bottom view and a cross-sectional view of the manhole cover made of a casting according to the first embodiment of the present invention, and a cross-sectional view thereof taken along the line BB, 5 is a manhole cover body, 6 is a plate portion of the manhole cover body 5, 7 is a cross-shaped reinforcing rib provided on the lower surface of the plate portion 6, 8 is a surrounding portion formed in the central portion of the reinforcing rib 7, and 9 and 9 are auxiliary ribs provided radially inside the surrounding portion 8. is there. In this embodiment, the two auxiliary ribs 9, 9 are provided in an X shape, but the number of auxiliary ribs may be two or more.

  Thus, in this embodiment, as shown in FIG. 4, the height h of the auxiliary rib is provided approximately half lower than the height H of the surrounding portion 8.

  Table 2 shows the specifications of Example 1 and the inspection results based on the standard 2.

  As shown in Table 2, the manhole cover of Example 1 had a deflection of 1.45 mm, a residual deflection of 0 mm, and obtained a result that it did not break under a load of 700 kN.

  From this result, the manhole cover of Example 1 according to the present invention shows that the residual deflection is lower than M2 and has high performance despite the fact that the weight is smaller than the manhole cover M2 satisfying the above-mentioned criterion 2. Satisfies criterion 2.

  As described above, the auxiliary ribs 9 and 9 having an underlined arch shape are radially provided in the surrounding portion 8 provided in the center of the back surface of the manhole cover 5, thereby obtaining lighter weight than the manhole cover M2 and the same strength as the manhole cover M2. be able to.

  5 and 6 show a bottom view of the second embodiment and a cross-sectional view taken along the line C-C. The difference between this embodiment and the first embodiment is that the auxiliary ribs 9 'and 9' are X-shaped. The auxiliary ribs 9 ′ and 9 ′ are different in that the central portions of the auxiliary ribs 9 ′ and 9 ′ are low, and both ends connected to the surrounding portion 8 are the same as the lower surface of the surrounding portion 8. In this case, a material that is the same as that of the first embodiment can be made lighter.

  FIGS. 7 and 8 show a bottom view of the third embodiment and a cross-sectional view taken along the line D-D. The difference between this embodiment and the second embodiment is that there are four arch-shaped lower edges. Auxiliary ribs 9 ″, 9 ″, 9 ″, 9 ″ are provided in an X shape, the center portion of each auxiliary rib 9 ″ is low, and the crossing portion is the same as the height of the surrounding portion 8, but the performance is different. In particular, the second embodiment is the same as the second embodiment.

  FIGS. 9 and 10 show a bottom view of the fourth embodiment and a cross-sectional view taken along the line E-E. In this embodiment, a circular encircling portion is provided at the center of the back surface of the plate portion 11 of the manhole cover body 10. 12, radially reinforcing ribs 13 are provided radially outside the surrounding portion 12, and linear auxiliary ribs 14, 14 are also provided in the surrounding portion 12, and the auxiliary ribs 14, 14 are As shown in FIG. 10, the lower edge has an arch shape, and the height h of the central portion is approximately half lower than the height H of the surrounding portion 11.

  In the case of the fourth embodiment shown in FIGS. 9 and 10, the load strength of the manhole cover can be increased as in the second and third embodiments, and the weight can be reduced.

  FIGS. 11 and 12 show a bottom view of the fifth embodiment and a cross-sectional view taken along the line F-F. Reference numeral 15 denotes a manhole cover body, 16 denotes a plate portion of the manhole cover body 14, and 17 denotes a lower surface of the plate portion 16. The provided cross-girder-shaped reinforcing ribs 18 are enclosing portions formed in the central portion of the reinforcing rib 17, and 19 and 19 are curved auxiliary ribs provided in a bowl shape inside the enclosing portion 18.

  In the fifth embodiment, as shown in FIG. 12, the height h of the auxiliary rib 19 is provided approximately half lower than the height H of the surrounding portion 18.

  In the fifth embodiment, the auxiliary ribs 19 and 19 are curved ribs as compared with the first to fourth embodiments in which the auxiliary ribs are linear, but the load strength is enhanced as in the first to fourth embodiments. Since it has the effect of being able to reduce the weight and the ribs are curved, the vibration characteristics are different from the parts with other linear reinforcing ribs. There is an effect to reduce.

  FIGS. 13 and 14 show a bottom view of the sixth embodiment and a cross-sectional view taken along the line G-G. In this embodiment, a circular encircling portion is provided at the center of the back surface of the plate portion 21 of the manhole cover body 20. 22 is formed, and radially linear reinforcing ribs 23 are provided outside the surrounding portion 22, and curved auxiliary ribs 24 and 24 are provided in the surrounding portion 22 in a bowl shape. Similar to Example 4.

  Although the lower edges of the auxiliary ribs 19 and 24 of the fifth and sixth embodiments are linear, the weight can be further reduced by forming an arch shape.

  FIGS. 15 and 16 show a bottom view of the seventh embodiment and a cross-sectional view taken along the line H-H of this embodiment. This embodiment includes auxiliary ribs 9 for the manhole cover of the first embodiment shown in FIGS. Further, reinforcing ribs 9 a, 9 a, 9 a, 9 a are provided at the crossing portion 9, and the reinforcing rib 7 a lower than the height of the reinforcing rib 7 or the auxiliary rib 9 on the back surface of the plate portion 6 outside the enclosure portion 8. , 7a, 7a, 7a (2 mm height in the embodiment).

  According to this configuration, the thickness of the plate portion 6 can be further reduced as compared with the case of the first embodiment, and therefore, weight reduction and cost reduction can be achieved.

  17, FIG. 18 and FIG. 19 show a bottom view of the eighth embodiment, a cross-sectional view taken along the line II, and a partial cross-sectional view taken along the line JJ. This embodiment is shown in FIGS. In this embodiment, a strength-enhancing flesh portion 7b is provided at the intersection of the auxiliary rib 7 and the surrounding portion 8 of the manhole cover of Example 1.

  Since the load applied to the manhole cover is concentrated at the intersection of the auxiliary rib 7 and the surrounding part 8, the strength of the manhole cover can be made higher than in the case of the first embodiment.

5 Manhole cover body 6 Plate part 7 Reinforcement rib 8 Enclosure part 9 Auxiliary rib

Claims (7)

A reinforcing rib is provided on the back surface of the plate portion, and a polygonal or annular surrounding portion is formed at the center of the back surface, and auxiliary ribs having a lower edge lower than the height of the surrounding portion are provided radially in the surrounding portion. A manhole cover. A manhole characterized in that a reinforcing rib is provided on the back surface of the plate portion, and a polygonal or annular surrounding portion is formed in the center of the back surface, and auxiliary ribs having an arched lower edge are provided radially in the surrounding portion. lid. A manhole cover characterized in that a reinforcing rib is provided on the back surface of the plate portion, a polygonal or annular surrounding portion is formed at the center of the back surface, and a curved auxiliary rib is provided in the shape of the inside of the surrounding portion. 4. The manhole cover according to claim 1, wherein a lower edge of the auxiliary rib is formed in an arch shape. The reinforcing ribbing portion is provided integrally with the auxiliary rib and the plate portion at the crossing portion of the auxiliary rib provided at the polygonal or annular enclosure provided at the center of the back surface of the plate portion. The manhole cover according to any one of claims 1 to 4. The manhole cover according to any one of claims 1 to 5, wherein a reinforcing rib having a lower height than other reinforcing ribs or auxiliary ribs is provided on the back surface of the plate portion outside the enclosing portion. A reinforcing portion is provided integrally with the reinforcing rib, the enclosure portion and the plate portion at the intersection of the polygonal or annular enclosure portion and the reinforcement rib provided at the center of the back surface of the plate portion. The manhole cover according to any one of claims 1 to 6.

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