Raboisson

Claim 1

IN A DRAFTING APPARATUS, IN COMBINATION, AT LEAST FOUR CONSECUTIVE SPACED PAIRS OF DRIVEN DRAFTING ROLLS DISPOSED SPACED FROM EACH OTHER AT FIXED PREDETERMINED INTERVALS DEFINING A DRAFTING FIELD HAVING A VARIABLE LENGTH SUITABLY ADJUSTABLE FOR THE LENGTH OF THE FIBERS BEING DRAFTED, EACH PAIR OF ROLLS COMPRISING AN ELONGATED LOWER ROLL AND AN UPPER ROLL, A DRIVEN UPPER ENDLESS APRON AND A DRIVEN LOWER ENDLESS APRON COOPERATIVE WITH A CORRESPONDING PAIR OF SAID ROLLS, THE UPPER ROLLS OF THREE OF NEXT SUCCESSIVE PAIRS OF SAID PAIRS OF ROLLS BEING INTERCHANGEABLE FOR VARYING THE LENGTH OF SAID DRAFTING FIELD, ONE OF THE UPPER ROLLS OF SAID PAIRS FOR VARYING THE LENGTH OF SAID DRAFTING FIELD COMPRISING A TENSION APPLYING ROLL HAVING TWO AXIALLY SPACED SMOOTH PERIPHERAL PORTIONS COOPERATIVE WITH THE CORRESPONDING LOWER ROLL, THE OTHERS OF SAID UPPER ROLLS FOR VARYING THE LENGTH OF SAID DRAFTING FIELD HAVING TWO AXIALLY SPACED PORTIONS WITH A NECK OF REDUCED DIAMETER BETWEEN THEM, EACH OF SAID TWO PORTIONS COMPRISING TWO AXIALLY SPACED COLARS DEFINING AXIALLY ON THE CORRESPONDING PORTION A SECTION OF PREDETERMINED REDUCED DIAMETER, THE SECTION OF SAID TWO PORTIONS HAVING A COMMON DIAMETER AND SAID ONE OF THE INTERCHARGEABLE UPPER ROLLS FOR VARYING THE LENGTH OF THE FIELD BEING DISPOSED ALTERNATIVELY IN POSITION TO COOPERATE WITH SAID UPPER APRON AND IN ONE OF THE PAIRS OF ROLLS UPSTREAM THEREOF IN DEPENDENCE UPON THE DIRECTION OF TRAVEL OF THE FIBERS THROUGH SAID APPARATUS.