Rotation resistant friction adapter for plunger driver of drug delivery device
First Claim
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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Accused Products
Abstract
A method and system are disclosed for driving a plunger in a drug reservoir. In some embodiments, a variable friction element interconnects between a pushing shaft and a wall of the reservoir. For example, rotation of a driving element in a first direction relative to the pushing shaft may advance the pushing shaft in the reservoir. The friction element may have increased friction resistance to rotation of the pushing shaft in the first direction in comparison to frictional resistance to advancing the pushing shaft. For example, the increased friction may result from wedging a radial element between the pushing shaft and the wall of the reservoir.
617 Citations
15 Claims
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
- the assembly comprising;
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11. A method of advancing a plunger in a drug reservoir comprising:
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Providing a telescoping assembly that extends by rotating a driver in a first rotational direction with respect to a pushing shaft mated to the driver, said pushing shaft including an anisotropic friction element in contact with a wall of the reservoir, said friction element comprising a disk and a plurality of independent radial elements extending radially from the disk, 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; rotating said driver in said first rotational direction; wedging said friction element between said pushing shaft and said wall as result of said rotating; inhibiting rotation of said pushing shaft as a result of said wedging; and unwedging said friction element to facilitate advancing of said pushing shaft. - View Dependent Claims (12, 13, 14, 15)
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Specification