range of rotation so that they automatically align themselves to be parallel to the heated shoes when they are contacted thereby this rotatable insert feature obviates the need for precise laborious alignment efforts alternatively a pair of rotatable blades are pivotally attached to the shoes and act against a fixed anvil surface thereby automatically aligning themselves to be parallel to the anvil surface application_number US 34816003 A description referring now to the figures there is shown an anvil assembly 10 useable with a packaging machine for pressing a covering sheet onto a package the anvil assembly 10 is attachable to the packaging machine and provides a pair of flat surfaces against which heated shoes may press a cover sheet and a packaging tape together the anvil assembly 10 generally has inserts 12 a base 14 and a pin 16 the pin 16 is supported by the base 14 and the inserts 12 have a limited range of rotation around the pin 16 the inserts 12 have top surfaces 20 which are straight flat and have widths 22 widths 22 define the maximum width of the seals that may be made between the covering sheet and the flanges of the packaging tape it is envisioned that the inserts 12 of the anvil assembly 10 are.