INTRAOCULAR LENS INJECTOR WITH FRICTIONAL ELEMENTS TO VARY THE PLUNGER FRICTION AS THE FRICTIONAL FORCE OF THE LENS INJECTION VARIES TO MAINTAIN A NET CONSTANT FORCE INJECTION
593500 Disclosed is a device for injecting an intraocular lens into an eye with features to compensate for variable lens insertion forces by varying the frictional resistance of the device. The device comprises a tubular housing having a longitudinal axis and a passageway along the longitudinal axis, and a plunger shaft disposed within and moveable along the passageway of the tubular housing over an operating range. The tubular housing and the plunger shaft have frictional engaging features configured to produce a varying plunging friction along the operating range to offset one or more changes in plunging resistance arising from injection of the lens into the eye. The frictional engaging features comprise a slot extending longitudinally along the tubular housing and having a varying width and a tab that extends transversely from the plunger shaft and frictionally engaging with side walls of the slot as the plunger shaft is translated along the operating range. The frictional engaging features are configured to produce the varying plunging friction according to a pre-determined unloaded plunging friction profile having one or more changes in plunging friction that complement corresponding changes in plunging resistance characteristic to injection of or folding of the lens into the eye, or both.
