Manhole cover and method for manufacturing same
View Patent ↗A manhole cover maintains a strength and weight the same as those of conventional manhole covers made of cast iron, eliminates the risk of theft, and achieves improved corrosion resistance and sealing properties. The manhole cover comprises: a base unit made of composite materials having compositions containing 12 to 18 wt % of glass fiber, 17 to 23 wt % of a polyester resin, with the remainder being calcium carbonate (CaCO3), wherein the base unit is mounted on the manhole such that an upper portion of the base unit is exposed aboveground; and a metal reinforcement unit which is uniformly distributed within the base unit to reinforce the base unit and increase weight and strength of the base unit.
1. A manhole cover, comprising:
a base made of a composite material having 12-18 weight % of a glass fiber, 17-23 weight % of a polyester resin and a remaining weight % of CaCO3, the base being mounted in a manhole and having an exposed top; and
a metallic reinforcing member which is uniformly filled in the interior so as to reinforce the base and increase the weight and strength,
wherein said base contains 0.7˜1.3 weight % of a UV blocking agent to block ultraviolet rays and enhance sterilization,
wherein the reinforcing member includes first to fourth elongate wires, all converging into a first point at an outer circumference of the base, the first wire extending from the first point to a second point at a first inner central circle around a central point of the base, the second wire extending from the first point to a third point at the first inner central circle, the third point being opposite to the second point, the third wire extending from the first point to a fourth point at a second inner central circle around the central point of the base, the fourth wire extending from the first point to a fifth point at the second inner central circle, the fourth point being opposite to the fifth point, the first circle having a diameter larger than a diameter of the second circle, and
wherein the base has a thickness to taper in a radial direction from a central region thereof toward a circumference region thereof.