Rotation resistant friction adapter for plunger driver of drug delivery device

  • US 9,987,432 B2
  • Filed: 09/22/2015
  • Issued: 06/05/2018
  • Est. Priority Date: 09/22/2015
  • Status: Active Grant
First Claim
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1. An assembly for driving a plunger in a drug reservoir, the plunger dividing between a drug in a distal portion of the reservoir and a proximal opening of the reservoir;

  • the assembly comprising;

    a telescoping shaft that extends by rotation of a driving element in a first rotational direction with respect to a distal shaft;

    a distal end of said distal shaft configured to engage the plunger; and

    an anisotropic friction element extending from said distal shaft, said friction element comprising a disk and a plurality of independent radial elements extending radially from the disk to contact an interior side wall of the reservoir, said radial elements extending from the disk toward the first rotational direction to wedge between said interior wall and said distal shaft when said distal shaft is rotated in said first rotational direction, said radial elements having respective leading edges and trailing edges, at least one of the leading edges extending radially from the disk at a first angle and a trailing edge associated with a same radial element as the at least one of the leading edges extending radially from the disk at a second angle, the first angle being steeper than the second angle.

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