Nippon Concrete Kogyo Kabushiki Kaisha

Mitsuo Ohoka

Senri Okada

Shinzo Hasegawa

Labor-consuming bolting operation as required with conventional forms of the gapped or split type has been ingeniously expelled by the provision of a form structure comprised essentially of a rigid tubular frame, a resilient gapped tubular casing arranged therein as a form in which concrete is to be placed, and camming means arranged on the inside of the rigid frame and on the outside of the resilient casing and cooperable to act upon the resilient tubular casing radially and circumferentially thereof with axial movement of such resilient casing relative to the rigid frame so as to close the gap in the resilient casing while holding the latter in coaxial relation to the rigid frame, any loss of moisture content of concrete during centrifugal forming operation can be effectively prevented by arranging an appropriate packing element on the resilient casing along the gap therein.

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Ohtone, Japan

Mitsuo Ohoka