To provide a cylindrical concrete form which is formed of a synthetic resin, reusable, and facilitates removal thereof after hardening of concrete.
The cylindrical concrete form 1 is formed of the synthetic resin, and either its outer peripheral surface or its inner peripheral surface has a spiral projection 1a formed thereon. In an apparatus for producing the cylindrical concrete form, an extruding die section includes a die mounting cylinder, an outer extruding die mounted on the die mounting cylinder, an inner extruding die housed in the outer extruding die, for controlling the flow rate of molten resin, and a cylindrical lip fixed to the outer extruding die. Then, by changing the arrangement of the inner extruding die, the flow rate of the molten resin can be adjusted.
MOGI OSAMU
MURAKAMI KIYOSHI
SIGMA KIKI CO LTD
ECO WAVE KK