Abstract: A method and apparatus for manufacturing bent pipes of a composite material composed of resin and filling materials such as reinforcing materials and aggregates by employing a cylindrical molding tool which is deformable between straight-axis form and bent-axis form. Materials are supplied into the molding tool held in horizontally straight condition while the tool is rotated about a horizontal axis, and are molded into a pipe by centrifugal molding. Rotation of the tool is stopped when the pipe molded therein is in uncured state, then the tool is subjected to bending. The resulting bent pipe is removed after it is cured. Before the tool is bent, a bag made of a flexible sheet material is inserted into the pipe and inflated to straighten out the inner periphery of the pipe so as to protect the pipe from any possibility of deformation during bending operation.

Abstract: A method and apparatus for manufacturing bent pipes of a composite material composed of resin and filling materials such as reinforcing materials and aggregates by employing a cylindrical molding tool which is deformable between straight-axis form and bent-axis form. Materials are supplied into the molding tool held in horizontally straight condition while the tool is rotated about a horizontal axis, and are molded into a pipe by centrifugal molding. Rotation of the tool is stopped when the pipe molded therein is in uncured state, then the tool is subjected to bending. The resulting bent pipe is removed after it is cured. Before the tool is bent, a bag made of a flexible sheet material is inserted into the pipe and inflated to straighten out the inner periphery of the pipe so as to protect the pipe from any possibility of deformation during bending operation.

Abstract: A centrifugal molding apparatus for manufacturing composite material pipes comprising a rotary mold and operating arm means extensible into and retractable from the rotary mold; the operating arm means having, in sequence from the front end thereof, a press roll portion for uniformalizing the interior of a pipe being molded, a first resin-liquid supply portion, a second resin-liquid supply portion, a chopped-strand supply portion, a third resin-liquid supply portion, a sand smoothing portion for smoothing sand supplied on to resin liquids, a sand supply portion, and a roving supply portion.According to the invention, the operating arm means have various functions, and by causing them to extend into and retract from the rotary mold one or more times it is possible to mold various kinds of composite material pipes efficiently.