Syringe

Abstract

A syringe capable of remote and/or automatic control. The syringe comprises a housing defining a main chamber, a piston at one end of the chamber and biasing means for urging the piston toward the other end of the chamber, and an opening into the chamber for liquid to pass. The piston is prevented from moving by a fusible element seated on the piston and on a fuse stop for preventing the movement. A heater is provided near the fuse stop which, when energized, melts that end of the fusible element to reduce its length and thereby permit movement of the piston under the urging of the biasing means. In this way injection or aspiration is accomplished. The heater may be energized and deenergized at will and when deenergized the fusible element ceases to be melted and the movement of the piston stops. This results in a syringe which can be turned on and off, which can inject or aspirate different and selected amounts of liquid depending upon the amount of time the heater has been on, and which can be operated for either injection or aspiration a plurality of times during the stroke from end of the chamber to the other. In a preferred embodiment, the heater and fuse stop are one and the same element.