Method of making thin-walled plastic screw caps

Claim 1

A METHODOF MAKING A THIN WALLED PLASTIC SCREW CAP HAVING A UNIFORM WALL THICKNESS OF THE THREAD PAORTION OF THE CAP COMPRISING THE STEPS OF B. PROVIDING A THIN-WALLED UNTHREADED CUP HAVING A SUBSTANTIALLY CYLINDICAL WALL OF SUBSTANTIALLY UNIFORM THICKNESS AT ALL POINTS SLONG THE WALL, C. INSERTING INTO SAID CUP A THREADED MATERIAL SLIGHTLY LARGER IN EXTERNAL DIAMETER THAN THE INSIDE DIAMETER OF THE CUP WHILE SUBJECTING THE CUP TO A SUFFICIENTLY HIGH TEMPERATURE TO SOFTEN ITS WALLS SUFFICIENTLY SO THAT THE CUP SIDE WALL HUNG THE MANDREL AND CONFORMS CLOSELY TO THE THREADED SHAPE OF THE MANDREL BOTH AT THE INNER SURFACE AND AT THE OUTER SURFACE OF THE CUP SO AS TO RETAIN ITS WALLS THICKNESS SUBSTANTIALLY UNIFORM, D. ALLOWING THE CUP TO COOL SUFFICIENTLY TO RETAIN THE THREADED SHAPE IMPARTED TO IT BY THE MANDREL E. UNSCREWING THE THUS THREADED CUP FROM THE MANDREL, F. SAID CUP BEING IN A RETAINERR HAVING A SMOOTH-EALLED RECESS OF SUFFICIENTLY LARGE DIAMETER TO ACCOMMODIATE THE THREADED CUP AFTER INSERTION OF THE MANDREAL, WITHOU BINDNG, G. SAID CUP HAVING A BEADED RIM WHICH RESTS ON THE SURFACE OF SAID RETAINER WHEN THE CUP IS IN THE RECESS, SAID BEADED RIM BEING THICKER, AND THEREFORE STORAGE THAN THE WALL OF THE CUP, H. SAID UNSCREWING OPERATION BEING ACCOMPLISHED BY HOLDNG A ROTATING FRICTION WHEEL AGAINST THE SAID BEADED RIM OF THE CUP SO AS TO SPIN IT OFF THE MANDREL, WHILE HOLDING THE MANDREL AGAINST ROTATION.