Method and apparatus for forming strip material into tube

Claim 1

A METHOD OF FORMING A TUBE FROM AT LEAST TWO NARROW ELONGATED STRIPS OF RESILIENT SHEET MATERIAL HAVING INTEGRAL INTERLOCKABLE TABS AND RECESSES FORMED ALONG THE LONGITUDINAL EDGES OF THE STRIPS, COMPRISING CURLING AT LEAST TWO SEPARATE LENGTHS OF THE SAID STRIPS ABOUT THEIR LONGITUDINAL AXES INTO TROUGHED FORM AND JOINING THE CURLED STRIPS TOGETHER IN SIDE-BY-SIDE RELATIONSHIP ALONG EACH OF THEIR ADJACENT LONGITUDINAL EDGES OF THE INTRODUCTION OF THE TABS OF ONE EDGE OF ONE STRIP INTO THE CO-OPERATING RECESSES OF THE ADJACENT EDGE OF THE ADJACENT STRIP TO FORM A TUBULAR SHAPE HAVING A NUMBER OF INTERLOCKED LONGITUDINAL SEAMS, CORRESPONDING TO THE NUMBER OF STRIPS, IN EACH SEAM THE TABS OF ONE STRIP ARE PASSED THROUGH THE CO-OPERATING RECESSES TO THE ADJACENT STRIP IN THE INWARD DIRECTION WITH RESPECT TO THE SAID TUBE SO THAT THEY WILL BE AGINST THE INSIDE SURFACE OF THE SAID TUBE, THE TABS OF EACH STRIP IS INTRODUCED INTO SAID RECESSES ARE DIRECTED PAST THE CONVEX SURFACE AND INWARDLY TOWARDS THE INNER CONCAVE SURFACE OF AN ADJOINING CURLED STRIP, AND SAID STRIPS WITH THEIR TABS INTERFITTED IN SAID RECESSES ARE FURTHER GUIDED INTO A CONTINUOUS TUBULAR SHAPE WITH THE TABS OF EACH STRIP BEING MOVED AGAINST THE INNER SURFACE OF A RESPECTIVE ADJOINING STRIP TO COMPLETE SAID TUBE.

Claim 2

A METHOD OF FORMING A TUBE FROM AT LEAST TWO NARROW ELONGATED STRIPS OF RESILIENT SHEET MATERIAL HAVING INTEGRAL INTERLOCKABLE TABS AND RECESSES FORMED ALONG THE LONGITUDINAL EDGES OF THE STRIPS, COMPRISING CURLING AT LEAST TWO SEPARATE LENGTHS OF THE SAID STRIPS ABOUT THEIR LONGITUDINAL AXES INTO TROUGHED FORM AND JOINING THE CURLED STRIPS TOGETHER IN SIDE-BY-SIDE RELATIONSHIP ALONG EACH OF THEIR ADJACENT LONGITUDINAL EDGES OF THE INTRODUCTION OF THE TABS OF ONE EDGE OF ONE STRIP INTO THE CO-OPERATING RECESSES OF THE ADJACENT EDGE OF THE ADJACENT STRIP TO FORM A TUBULAR SHAPE HAVING A NUMBER OF INTERLOCKED LONGITUDINAL SEAMS, CORRESPONDING TO THE NUMBER OF STRIPS, IN EACH SEAM THE TABS OF ONE STRIP ARE PASSED THROUGH THE CO-OPERATING RECESSES TO THE ADJACENT STRIP IN THE INWARD DIRECTION WITH RESPECT TO THE SAID TUBE SO THAT THEY WILL BE AGINST THE INSIDE SURFACE OF THE SAID TUBE, THE TABS OF EACH STRIP IS INTRODUCED INTO SAID RECESSES ARE DIRECTED PAST THE CONVEX SURFACE AND INWARDLY TOWARDS THE INNER CONCAVE SURFACE OF AN ADJOINING CURLED STRIP, AND SAID STRIPS WITH THEIR TABS INTERFITTED IN SAID RECESSES ARE FURTHER GUIDED INTO A CONTINUOUS TUBULAR SHAPE WITH THE TABS OF EACH STRIP BEING MOVED AGAINST THE INNER SURFACE OF A RESPECTIVE ADJOINING STRIP TO COMPLETE SAID TUBE.