Apparatus for making spirally corrugated rubber tubing

Claim 1

APPARATUS FOR USE IN MAKING SPIRALLY CORRUGATED RUBBER TUBING FROM A RAW RUBBER TUBE BLANK OF SUBSTANTIALLY UNIFORM CROSS SECTION, SAID APPARATUS COMPRISING IN COMBINATIN AND ELONGATED HOLLOW CYLINDRICAL MANDREL ADAPTED TO RECEIVE THE TUBE BLANK OVER IT IN TELESCOPIC SUPPORTING RELATION, A RESILIENT HELICAL FORMER RECIEVABLE TELESCOPICALLY OVER THE MANDREL AND A TUBE BLANK SUPPORTED ON THE LATTER, THE FORMER COMPRISING A SPRING COIL ELEMENT THE CONVOLUTIONS OF WHICH, IN THE UNSTRESSED CONDITION, LIE AGAINST ONE ANOTHER AND YIELDINGLY RESIS: AXIAL SEPARATION, THE COIL CONVOLUTIONS HAVING INTERNAL PERIPHERAL EDGE PORTIONS WHICH COLLECTIVELY DEFINE A CYLINDER LARGER THAN THE EXTERNAL SURFACE OF THE SUPPORTED TUBE BLANK FOR WHICH THE APPARATUS IS DESIGNED WHEREBY TO PROVIDE AN ANNULAR CLEARANCE BETWEEN THE RECEIVED FORMER AND SUCH SUPPORTED TUBE, THE RADIAL CROSS SECTIONAL DIMENSION OF THE ELEMENT COMPRISING THE SPRING COIL BEING GREATER THAN ITS AXIAL CROSS SECTIONAL DIMENSION WHEREBY THE FORMER EXHIBITS STRONG RESISTANCE TO RADIAL DEFORMATION FORCES AND YIELDS TO AXIAL STRETCHING FORCES, MEANS INCLUDING MEANS PROVIDING PASSAGES IN THE MANDREL THROUGH WHICH FLUID UNDER DISTENDING PRESSURE IS FORCED INTO THE INTERIOR OF SUCH SUPPORTED AND EMBRACED TUBE TO EXPAND THE TUBE INTO ENGAGEMENT WITH SAID INTERNAL EDGE PORTIONS OF THE FORMER, THE FORMER BEING ADAPTED, UPON THE APPLICATIN TO ITS ENDS OF OPPOSITE AXIAL TENSIONING FORCES, TO EXTEND AND DISTRIBUTE ITS CONVOLUTIONS ALONG THE TUBE BLANK OVER WHICH IT IS TELESCOPED AND BEING FURTHER ADAPTED, UPON THE APPLICATION OF DIFFERENTIAL DISTENDING FLUID PRESSURE TO BE SUPPORTED AND EMBRACED TUBE BLANK TO ENGAGE THE LATTER AD CONTROL DISTENSION OF THE TUBE BLANK WHILE BOTH THE TUBE BLANK AND THE EXTENDED FORMER ARE SUPPORTED BY THE MANDREL, AND SAID FORMER WHEN ITS CONVOLUTIONS ARE SO DISTRIBUTED BEING FURTHER ADAPTED, UPON THE RELEASE OF SAID OPPOSITE TENSIONING FORCES, TO APPLY THROUGH ITS INHERENT RESILIENCY CONTRACTING AXIAL FORCES TO AN EXPANDED AND ENGAGED TUBE, WHEREBY OTHER FORCES APPLIED TO SUCH A TUBE IN COLLAPSING IT AXIALLY ARE AUGMENTED THROUGHOUT THE COLLAPSING OPERATION BY SAID CONTRACTING FORCES APPLIED BY THE RESILIENT FORMER.