| 摘要 |
A machine and method for forming a spring coil in a length of hollow, cylindrical thermoplastic tubing comprises clamping the ends of a predetermined length of cylindrical thermoplastic tubing between first and second opposing spaced clamping members. In the machine, these clamping members include aligned first and second sections of a mandrel. These first and second clamping members then are rotated relative to one another by a predetermined amount selected to be slightly in excess of 360°, while the mandrels are simultaneously moved toward one another, to shorten the distance between the ends of the length of tubing, while the coil is formed. At the end of this relative rotation, the mandrel sections engage one another. The clamped tube, with the coil now formed around the mandrels, is rotated and simultaneously heated to the thermosetting temperature of the tubing. After a sufficient time to establish thermosetting of the coil, the heat is removed. Rotation continues while the tube is cooled. Following the cooling cycle, the apparatus operates to release the tubing with the formed coil in it from the machine.
|
