ONE-PIECE VENTABLE PISTON FOR A DISPENSING APPARATUS, A DISPENSING APPARATUS WITH SAME, AND METHOD OF MAKING SAME

摘要

A piston has a one-piece body having a first portion and a second portion. The second portion is integrally formed with the first portion, is flexibly movable between a first position and a second position relative to the first portion, and is biased toward the first position. The first portion has an orifice, and the second portion has a seal member. When the second portion is disposed in the first position, the seal member is disposed in a sealed arrangement with the orifice, and when the second portion is disposed in the second position, the seal member is disposed in an unsealed arrangement with the orifice.