U.s. pat. no. 4,538,920, with stepped chamber

摘要

A dispensing cartridge for use with a hand-held applicator has a chamber with a first section and a second section. The second section has a smaller cross-sectional area than the first section such that the chamber has a stepped configuration. A piston is slidably received in the chamber and has a head portion that is received in the second section and a tail portion that is received in the first section. As a force is applied to the tail portion, the head portion advances to expel material through an outlet opening. The cartridge is especially useful for dispensing compositions having a relatively high viscosity such as dental pastes and the like.