Apparatus for dispensing a predetermined volume of paste-like fluid

摘要

A piston driving device for dispensing a predetermined small amount of paste-like material from a nozzle in response to an electrical signal without any time-delay is enabled by the slow rotation of a ball-screw shaft, the rotation being reduced by a differential gear system. A female ball-nut fitted onto the ball-screw shaft causes a piston plunger to advance at very low speed such that dispensing of the predetermined volume of paste-like fluid is possible. Vertical motion of a nozzle is compensated by vertical motion of a piston driving device such that the relative position of a piston against a nozzle is unchanged.