Plunger for drug delivery device
First Claim
1. A plunger system, comprising:
- a collapsible plunger;
a push rod coupled to the plunger;
a drive spring positioned around the push rod; and
a needle conduit positioned through the push rod,the collapsible plunger comprising a front surface, a back surface, and a cavity extending into the plunger and surrounded by the back surface, wherein the cavity forms an internal portion of the collapsible plunger, wherein a radial torsion spring is positioned in the cavity of the collapsible plunger.
2 Assignments
0 Petitions
Accused Products
Abstract
Plunger systems for expelling a liquid drug from a drug container within a wearable drug delivery device are provided. A rotation system coupled to a plunger rotates the plunger about a central axis of the plunger to overcome a static friction between the plunger and the drug container. After rotating the plunger, a drive system moves the plunger forward into the drug container to expel the liquid drug for delivery to the patient. A collapsible plunger includes a cavity. A radial torsion spring positioned in the cavity can provide an outward radial force on the collapsible plunger. The cavity enables the collapsible plunger to compress radially when entering and passing through a region of a drug container having a relatively narrower width. The radial torsion spring can radially expand the collapsible plunger when entering and passing through a region of the drug container having a relatively wider width.
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Citations
22 Claims
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1. A plunger system, comprising:
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a collapsible plunger; a push rod coupled to the plunger; a drive spring positioned around the push rod; and a needle conduit positioned through the push rod, the collapsible plunger comprising a front surface, a back surface, and a cavity extending into the plunger and surrounded by the back surface, wherein the cavity forms an internal portion of the collapsible plunger, wherein a radial torsion spring is positioned in the cavity of the collapsible plunger. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A plunger system, comprising:
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a collapsible plunger; a push rod coupled to the plunger; a drive spring positioned around the push rod; a needle conduit positioned through the push rod; and a rotation system configured to rotate the plunger about a central axis of the plunger, wherein the rotation system is configured to rotate the plunger by a predetermined amount to overcome a static friction between the plunger and a drug container in which the plunger is disposed. - View Dependent Claims (19, 20, 21, 22)
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Specification