| 主权项 |
1. An apparatus for delivering an injectate to a patient, said apparatus comprising:
a chamber for holding the injectate, the chamber having an orifice through which the injectate is delivered disposed at a chamber distal end; a piston mechanism disposed at least partially in the chamber, the piston mechanism including
an outer piston slideably disposed in the chamber, said outer piston having a channel extending through the outer piston from a proximal end of the outer piston to a distal end of the outer piston, andan inner piston having an inner piston proximal end including a stop and an inner piston distal end including a plunger element, the plunger element being slideably disposed in the channel of the outer piston; and a driver element coupled to the inner piston and configured to cause movement of the piston mechanism in the chamber for delivery of the injectate; wherein the piston mechanism is configurable into a plurality of configurations including
a first configuration in which the stop of the inner piston is not in contact with the outer piston such that the inner piston is movable in the channel without causing movement of the outer piston, anda second configuration in which the stop of the inner piston is in contact with the outer piston such that the inner piston and the outer piston move together in the chamber. |
