Extruded tubes and cable sheaths

Claim 1

A METHOD OF CONTROLLING THE THICKNESS OF A SHEATH OR TUBE OF ALUMINUM OR OTHER METAL PRODUCED IN AN EXTRUSION PRESS IN WHICH THE THICKNESS IS DETERMINED BY THE DISTANCE BETWEEN ONE END OF THE MANDREL AND THE END FACE OF THE DIE APERTURE AND IN WHICH THE EXTRUDED PRODUCT IS COOLED IMMEDIATELY AFTER LEAVING THE DIE, COMPRISING THE STEPS OF REDUCING THE EXTRUSION PRESSURE GRADUALLY WHEN A STOOPAGE IS TO BE EFFECTED, PROGRESSIVELY ADJUSTING THE RELATIVE AXIAL SPACING OF THE MANDREL AND DIE FROM THE BEGINNING OF THE REDUCTION IN PRESSURE AND DURING ITS CONTINUANCE TO THE EXTENT NECESSARY TO COMPENSATE FOR THE REDUCTION IN THE ANNULAR GAP THAT WOULD OTHERWISE RESULT FROM THE VARIATION OF THE LOAD ON THE MANDREL AND DIE CAUSED BY THE CHANGING EXTRUSION PRESSURE, CONTINUING THE ADJUSTING OF THE MANDREL AND DIE TO COMPENSATE FOR THE REDUCTION IN THE ANNULAR GAP THAT WOULD OTHERWISE BE CAUSED BY THE COOLING AND CONSEQUENT CONTRACTION OF THE DIE, AND PROGRESSIVELY RE-ADJUSTING THE MANDREL AND DIE WHEN EXTRUSION IS RESUMED, TO THE EXTENT NECESSARY TO COMPENSATE FOR THE THERMAL AND ELASTIC EXPANSION OF THE DIE RESULTING FROM THE INCREASE IN TEMPERATURE AND PRESSURE.

Claim 2

A METHOD OF CONTROLLING THE THICKNESS OF A SHEATH OR TUBE OF ALUMINUM OR OTHER METAL PRODUCED IN AN EXTRUSION PRESS IN WHICH THE THICKNESS IS DETERMINED BY THE DISTANCE BETWEEN ONE END OF THE MANDREL AND THE END FACE OF THE DIE APERTURE AND IN WHICH THE EXTRUDED PRODUCT IS COOLED IMMEDIATELY AFTER LEAVING THE DIE, COMPRISING THE STEPS OF REDUCING THE EXTRUSION PRESSURE GRADUALLY WHEN A STOOPAGE IS TO BE EFFECTED, PROGRESSIVELY ADJUSTING THE RELATIVE AXIAL SPACING OF THE MANDREL AND DIE FROM THE BEGINNING OF THE REDUCTION IN PRESSURE AND DURING ITS CONTINUANCE TO THE EXTENT NECESSARY TO COMPENSATE FOR THE REDUCTION IN THE ANNULAR GAP THAT WOULD OTHERWISE RESULT FROM THE VARIATION OF THE LOAD ON THE MANDREL AND DIE CAUSED BY THE CHANGING EXTRUSION PRESSURE, CONTINUING THE ADJUSTING OF THE MANDREL AND DIE TO COMPENSATE FOR THE REDUCTION IN THE ANNULAR GAP THAT WOULD OTHERWISE BE CAUSED BY THE COOLING AND CONSEQUENT CONTRACTION OF THE DIE, AND PROGRESSIVELY RE-ADJUSTING THE MANDREL AND DIE WHEN EXTRUSION IS RESUMED, TO THE EXTENT NECESSARY TO COMPENSATE FOR THE THERMAL AND ELASTIC EXPANSION OF THE DIE RESULTING FROM THE INCREASE IN TEMPERATURE AND PRESSURE.