| 摘要 |
PROBLEM TO BE SOLVED: To provide an inexpensive form for manufacturing a culvert block capable of molding a predetermined flowing water cross section, by utilizing a core made of a resin in place of a form using an expensive core made of steel much lowered in production efficiency. SOLUTION: A rear side plank holds the core made of a resin having an arbitrary shape from the inner and outer surfaces thereof so as to obtain a predetermined cross-sectional dimension, and is provided with a length and inner diameter error absorbing means 50. The rear side plank is pivotally mounted on the rear part of a plinth, while a front side plank sliding to move forwardly and rearwardly is vertically provided on the front part of the plinth. Further, the form is provided not only with a length and inner diameter error absorbing means 60 in the same way as the rear side plank, but also with an advance and retreat mechanisms to be restricted by a restriction part 57. Air holes are provided to both of the side planks so as to communicate with the outside and the atmospheric pressure and temperature in the core made of the resin are made same to those of the outside during steam ageing to prevent thermal deformation. A predetermined equal flowing water cross section is molded by the buoyancy preventing means 70 of a hollow cylindrical body and the core made of the resin contracted in diameter by a temperature drop after demolding is easily pulled off to be made reusable. By this constitution, the inexpensive form enhanced in production efficiency can be provided. COPYRIGHT: (C)2004,JPO
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