| 摘要 |
PROBLEM TO BE SOLVED: To lighten a ditch grating made of a synthetic resin, and to obtain sufficient drainage capacity by molding the ditch grating of a plurality of support sections having hollow sections on the insides and a plurality of tread sections unified with the support sections. SOLUTION: The ditch grating made of the synthetic resin having at least one hollow section 7 on the inside and consisting of a polyacetal resin, etc., is molded, and formed of a plurality of support sections 2 and tread sections 3 unified with the support sections 2. When the ditch grating made of the synthetic resin is manufactured by an injection blow molding method, the injecting section of a pressure fluid injected into the synthetic resin for forming the hollow section to the ditch grating made of the synthetic resin is installed into a mold cavity, and the pressure fluid is injected into the synthetic resin from the support sections of the ditch grating. One or a plurality of the tread sections 3 of the ditch grating are formed, an opening area is increased by mounting the tread sections 3 in the longitudinal direction of the opening section of a ditch, and drainage from a reference surface is not disturbed. Accordingly, no rust is generated, and recycling can be facilitated. |
