Computer generated stopper.

摘要

A stopper or closure is provided as a closure for containers in which the stopper profile is computer generated to take into consideration radial stress at the stopper/container interface, and to eliminate tensile stress therealong which tensile stress is an indication that a portion of the stopper wall is not engaging the opposed container surface. The stopper of the invention is particularly appropriate for use in evacuated blood sample collection tubes for eliminating "gray bands" or regions where the stopper and the tube do not contact, and "red spots" formed in small cavities generated on the internal surface of the stopper at the withdrawal position of the blood collection needle having been inserted in the stopper.