摘要 |
A heat shrinkable plastic sleeve having an inner surface deformed in circumferentially spaced portions by unequal amounts from its normal heat stable or unstable configuration so as to provide different stresses in the circumferential direction whereby uniformity of heating of the sleeve throughout its thickness can be observed during heat shrinking by observing the shrinkage of the sleeve at its ends. Also, a method of making such sleeve in which a sleeve of heat shrinkable material is placed on a mandrel having expandable fingers, the sleeve is heated and the fingers are radially expanded and the sleeve is cooled to provide the desired sleeve. |