Mechanically actuated fluid infusion device

1. A fluid infusion device for delivery of a medication fluid to the body of a user, the fluid infusion device comprising:

a housing;

a fluid reservoir for the medication fluid, wherein the fluid reservoir is located in the housing, and wherein the medication fluid in the fluid reservoir is maintained under positive pressure;

a valve assembly located in the housing and coupled to the fluid reservoir;

a dosing mechanism located in the housing and coupled to the fluid reservoir via the valve assembly, the dosing mechanism comprising an adjustable fluid chamber that defines a user-selectable dosage volume, and the dosing mechanism comprising a mechanical actuator; and

a fluid conduit coupled to the dosing mechanism via the valve assembly, wherein at least a portion of the fluid conduit is external to the housing when the fluid infusion device is deployed for operation; wherein:

application of an actuation force to the mechanical actuator initiates a fluid delivery operation;

removal of the actuation force from the mechanical actuator initiates a refill operation;

during the fluid delivery operation, the valve assembly allows the medication fluid to flow from the adjustable fluid chamber into the fluid conduit for delivery to the body of the patient, while inhibiting flow of the medication fluid from the adjustable fluid chamber into the fluid reservoir; and

during the refill operation, the valve assembly allows the medication fluid to flow from the fluid reservoir into the adjustable fluid chamber, while inhibiting flow of the medication fluid from the fluid reservoir into the fluid conduit.

2. The fluid infusion device of claim 1 , wherein:

the valve assembly inhibits flow of the medication fluid from the fluid conduit to the fluid reservoir; and

the valve assembly inhibits flow of the medication fluid from the fluid conduit to the adjustable fluid chamber.

3. The fluid infusion device of claim 1 , wherein the fluid reservoir comprises a self-contracting reservoir bag.

4. The fluid infusion device of claim 1 , wherein the fluid reservoir comprises:

a resilient bladder; and

a structure operatively coupled to the resilient bladder to impart a compressive force to the resilient bladder.

5. The fluid infusion device of claim 1 , wherein the fluid reservoir comprises:

a barrel body having a fluid delivery end and a base opposite the fluid delivery end;

a plunger located in the barrel body; and

a biasing element located in the barrel body between the plunger and the base of the barrel body, wherein the biasing element biases the plunger toward the fluid delivery end.

6. The fluid infusion device of claim 1 , wherein the adjustable fluid chamber is adjustable in discrete steps that define a plurality of predetermined and calibrated dosage volumes.

7. The fluid infusion device of claim 1 , further comprising an adhesive patch having a first side affixed to the housing and a second side for attachment to the body of the patient.

8. The fluid infusion device of claim 1 , further comprising a fill port accessible from outside the housing, wherein:

the fill port is fluidly coupled to the fluid reservoir to facilitate filling of the fluid reservoir with the medication fluid during a filling operation; and

during the filling operation, the valve assembly inhibits flow of the medication fluid from the fluid reservoir to the fluid conduit.

9. A fluid infusion device for delivery of a medication fluid to the body of a user, the fluid infusion device comprising:

a housing;

a fluid reservoir to maintain the medication fluid under positive pressure, wherein the fluid reservoir is located in the housing;

a valve assembly located in the housing and coupled to the fluid reservoir;

a dosing mechanism located in the housing and coupled to the fluid reservoir via the valve assembly, the dosing mechanism comprising a mechanical actuator to adjust a fluid chamber of the dosing mechanism such that the fluid chamber defines a user-selectable dosage volume; and

a fluid delivery conduit coupled to the dosing mechanism via the valve assembly;

wherein:

in response to application of force to the mechanical actuator, the medication fluid in the fluid chamber is expelled through the fluid delivery conduit, while the valve assembly inhibits flow of the medication fluid from the fluid chamber to the fluid reservoir; and

in response to removal of the force, the mechanical actuator automatically retracts to refill the fluid chamber with the medication fluid from the fluid reservoir, while the valve assembly inhibits flow of the medication fluid from the fluid reservoir to the fluid delivery conduit and inhibits fluid flow from the fluid delivery conduit to the fluid chamber.

10. The fluid infusion device of claim 9 , wherein the user-selectable dosage volume is adjustable in discrete steps that define a plurality of predetermined and calibrated dosage volumes.

11. The fluid infusion device of claim 9 , wherein:

the user-selectable dosage volume is adjusted in response to rotation of the mechanical actuator about a major longitudinal axis; and

the mechanical actuator is actuated in response to application of the force in a direction aligned with the major longitudinal axis.

12. The fluid infusion device of claim 9 , wherein the fluid reservoir comprises a self-contracting reservoir bag.

13. The fluid infusion device of claim 9 , wherein the fluid reservoir comprises:

a resilient bladder; and

a structure operatively coupled to the resilient bladder to impart a compressive force to the resilient bladder.

14. The fluid infusion device of claim 9 , wherein the fluid reservoir comprises:

a barrel body having a fluid delivery end and a base opposite the fluid delivery end;

a plunger located in the barrel body; and

a biasing element located in the barrel body between the plunger and the base of the barrel body, wherein the biasing element biases the plunger toward the fluid delivery end.

15. The fluid infusion device of claim 9 , further comprising an adhesive patch having a first side affixed to the housing and a second side for attachment to the body of the patient.