Infusion pumps and methods with shape memory wire driven syringe mechanism
Inventors
Ho, Eduardo • Farshchi, Reza • Trevaskis, William T.
Assignees
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Publication Number
US-12758702-B2
Publication Date
2026-10-13
Expiration Date
Abstract
Disclosed herein are apparatuses and methods for an ambulatory infusion pump actuated with a shape memory alloy (SMA) wire. An SMA wire operated mechanism can include an actuator lever to increase the SMA wire's strain into a usable displacement to move a pawl that ratchets to a ratchet wheel to rotate a lead screw to advance a plunger a precise amount within a reservoir to deliver a precise amount of fluid.
Core Innovation
The claims describe an ambulatory infusion pump containing a reservoir and a syringe assembly with a plunger that dispenses a predetermined amount of medicament. A shape memory wire shortens upon actuation to move a pawl, directly or via an actuator lever, thereby rotating a ratchet wheel and the syringe assembly. Lever geometry amplifies the wire contraction into pawl displacement, and a reset spring restores the mechanism.
The syringe assembly includes a drive tube with internal threads interfaced with a lead screw attached to the plunger, such that rotation of the ratchet wheel advances the lead screw and plunger. Single-tooth increments correspond to predetermined delivery amounts, and alternative dual offset pawls provide half-tooth increments for increased dose resolution. The pump is wearable and is operable via an associated handheld controller.
Claims Coverage
The claims include three independent claims (claims 1, 11, and 19) reciting three inventive features directed to an ambulatory infusion pump driven by a shape memory wire.
Shape memory wire actuation of an aperture-fitted pawl and ratchet wheel
Claim 1 recites a syringe assembly and plunger with a ratchet wheel and a pawl having an elongate aperture configured to fit around a portion of the ratchet wheel teeth. Actuation shortens a shape memory wire to move a mechanically linked actuator lever and pawl, rotating the ratchet wheel and syringe assembly to dispense a predetermined amount of medicament.
Threaded drive tube and lead screw for plunger advancement
Claim 11 recites an elongate-lever pawl interfacing with the outer circumferential surface of the ratchet wheel, wherein the syringe assembly comprises an internally threaded drive tube interfaced with a lead screw attached to the plunger so that rotation of the ratchet wheel advances the plunger.
Elongate pawl configured to push the ratchet wheel upon actuation
Claim 19 recites an elongate-lever pawl interfacing with the outer circumferential surface of the ratchet wheel, configured such that shortening of the shape memory wire moves the pawl to push and rotate the ratchet wheel and syringe assembly to dispense medicament.
The three independent claims cover shape-memory-wire actuation of a ratchet-driven infusion pump, providing distinct pawl interfaces and a threaded drive tube and lead screw arrangement that advances the plunger.
Stated Advantages
One-tooth increments correspond to precise delivery amounts.
Two offset pawls provide half-tooth increments and doubled dose resolution.
Documented Applications
An ambulatory infusion pump that dispenses a predetermined amount of medicament from a reservoir.
Wearable insulin delivery.
Delivery of other medicaments.
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