Patent ID: 11957878
Assignee: BATTELLE MEMORIAL INSTITUTE
Field: Medical technology (Instruments)
Classification: CPC A | IPC A

Claim 15:
16. A method of injecting a medicament from a syringe, comprising:
providing a driving force that inserts a needle into skin of a patient at a proximal end of the syringe, then subsequently moves a plunger down the syringe from a distal position toward a proximal position;
wherein a spring having both a torsion mode and a compression mode is attached at one first end to a first surface and at one second end to a second surface;
wherein the second surface moves with the plunger and an early stage movement of the plunger toward the proximal position twists the spring to store energy in the spring;
and subsequently as the driving force due to the compression mode continues to move the plunger toward the proximal position, and the second surface moves with the plunger, the torsion mode of the spring rotates through a prescribed path to modify the driving force moving the plunger toward the proximal position.