Device for shaping a bell end to a tube

Abstract

Abstract 1. IN A DEVICE FOR SHAPING A BELL END ON A TUBE OF THERMOPLASTIC MATERIAL, WHEREIN THE BELL END HAS AN INNER SURFACE WITH A LARGER DIAMETER THAN ITS OPENING SO THAT THE INSIDE OF THE TUBE TAPERS RADIALLY INWARDLY FROM THE LARGER DIAMETER INNER SURFACE TOWARD THE OPENING THEREOF, AND WHEREIN THE SHAPING DEVICE HAS A CYCLINDRICAL MANDREL WITH AN OUTER PROFILE SHAPED SUBSTANTIALLY THE SAME AS THE SHAPE TO BE FORMED ON THE TUBE, THE MANDREL HAVING AN OUTER SURFACE THAT VARIES IN DIAMETER IN A STEPWISE MANNER FROM THE END THEREOF TO BE INSERTED IN THE TUBE, WITH THE TRANSITIONS BETWEEN ADJACENT STEPS OF THE MANDREL SURFACE GRADUALLY MERGING WITH ANGLES LESS THAN 45* WITH RESPECT TO THE AXIS THEREOF, AND WHEREIN SAID END OF THE MANDREL IS TAPERED SO THAT THE END DIAMETER IS LESS THAN THE INNER DIAMETER OF THE TUBE, THE IMPROVEMENT WHEREIN SAID MANDREL IS COMPRISED OF A CENTRAL MEMBER OF A MATERIAL THAT IS HARD IN COMPARISON TO SAID THERMOPLASTIC MATERIAL, SAID CENTRAL MEMBER HAVING A LARGEST DIAMETER PORTION SPACED FROM SAID END AND HAVING A DIAMETER THAT IS NOT SUBSTANTIALLY LESS THAN THE OUTER DIAMETER TO BE SHAPED, AND AN INTERMEDIATE PORTION BETWEEN SAID END AND SAID LARGEST DIAMETER PORTION AND HAVING A LESSER DIAMETER, AND SHAPING RING SLIDABLE ON SAID INTERMEDIATE PORTION, SAID SHAPING RING HAVING AT LEAST ONE OUTER SURFACE WITH A DIAMETER LARGER THAN THAT OF SAID LARGEST DIAMETER PORTION OF SAID CENTRAL MEMBER, SAID SHAPING RING BEING OF A MATERIAL HAVING A HARDNESS BETWEEN THAT OF SAID THERMOPLASTIC MATERIAL AT AMBIENT TEMPERATURE AND THAT OF SAID THERMOPLASTIC MATERIAL AT THE DEFORMING TEMPERATURE THEREOF, SAID SHAPING RING FURTHER HAVING AN INNER DIAMETER WHICH IS LESS THAN THE LARGEST DIAMETER OF SAID LARGEST DIAMETER PORTION, SAID SHAPING RING BEING AXIALLY REMOVABLE WITHOUT DEFORMATION OVER SAID END OF SAID CENTRAL MEMBER, WHEREBY SAID SHAPING RING IS REMOVED FROM SAID TUBE ONLY WHEN THE CENTRAL MEMBER IS AXIALLY DISPLACED FROM SAID RING. D R A W I N G

Inventors

• 👤 P Acda

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