Patent ID: 7390993
Filing Date: 2008-06-24
Classification: B29C,H05B

Abstract:
1. An electrical sleeve heater for an element having a generally cylindrical outer surface, the heater comprising: a generally helical coil centered on an axis and having a pair of opposite coil ends; a pair of generally coaxial, axially aligned, and similar tubes each fixed to a respective one of the coil ends and extending axially along the coil, whereby relative rotation of the tubes radially increases or decreases an inside diameter of the coil, the tubes having axially adjacent inner ends; and respective identical arrays of axially projecting and interengageable teeth on the tube inner ends for releasably fixing together the tube inner ends, whereby axial interengagement of the teeth of the tube inner ends after relative rotation to change the inside diameter of the coil locks the tubes angularly relative to each other and locks in position the changed inside diameter of the coil.