Becton, Dickinson and Company
DOUBLE-ACTING, TELESCOPING SCREW-DRIVEN PUMP MECHANISM DISPOSED EXTERNALLY TO RESERVOIR IN FLUID DELIVERY DEVICE

Abstract:

A fluid delivery device has a syringe barrel-type reservoir with plunger, and plunger driver assembly comprising double-acting, telescoping lead screws that is located behind and outside of the barrel. Simultaneously and counter-rotating sleeve screw and center screw telescope out of a nested configuration of the plunger driver assembly and into the reservoir at a rate of double their individual and equal pitch and lead parameters when the sleeve screw is rotated. A threaded nut and gear anchor disposed on an end of the barrel receive the sleeve screw and the threaded nut causes the sleeve screw to translate and rotate in response to motor operation. A distal end of the center screw can be keyed to a plunger pusher for anti-rotation constraint when the motor is imparting rotation on the threaded nut and sleeve screw.