Patent ID: 6939503

Claim:
A method for the manufacture of pipes of thermoplastics with transverse profile features, comprising mold segment halves ( 4 , 5 ) which are circulated and, subsequent to an extrusion head ( 7 ), disposed in two lines opposite to each other, with the mold segment halves ( 4 , 5 ) of a line not being interconnected, and which complement one another by twos along a straight molding path ( 2 ), forming a closed hollow mold; wherein each of the mold segment halves ( 4 , 5 ) of a line is guided out of the molding path ( 2 ) at the downstream end ( 70 ) thereof and substantially at right angles to a direction of production ( 6 ) by means of a conveying device ( 29 ) and is re-circulated to the upstream end ( 67 ) of the molding path ( 2 ), where it is again inserted in the molding path ( 2 ) and attached to the respective mold segment half ( 4 , 5 ) that leads in the direction of production ( 6 ); wherein downstream of the downstream end ( 70 ) of the molding path ( 2 ) and on both sides thereof, an additional first mold segment half ( 4 a , 5 a ) is kept in a first parking position ( 77 ) for insertion in the molding path ( 2 ); wherein at least one additional mold segment half ( 4 b , 5 b , 4 c , 5 c ) is kept in at least one additional parking position ( 78 , 79 ) between the first parking positions ( 77 ) for the first mold segment halves ( 4 a , 5 a ) and the downstream end ( 70 ) of the molding path ( 2 ), these additional mold segment halves ( 4 b , 5 b , 4 c , 5 c ) also being insertable in the molding path ( 2 ) wherein at least one further additional mold segment half ( 4 b , 5 b , 4 c , 5 c ) is moved out of a path of displacement ( 85 ) of the first mold segment halves ( 4 a , 5 a ), when the first mold segment halves ( 4 a , 5 a ) are moved from their first parking position ( 77 ) toward the molding path ( 2 ); and wherein at the least further additional mold segment half ( 4 b , 5 b , 4 c , 5 c ) is moved out of the path of displacement ( 85 ) of the first mold segment halves ( 4 a , 5 a ), when the first mold segment halves ( 4 a , 5 a ) are moved from the molding path ( 2 ) into the first parking position ( 77 ).