ROTATION RESISTANT FRICTION ADAPTER FOR PLUNGER DRIVER OF DRUG DELIVERY DEVICE

• US 20170080158A1
• Filed: 09/22/2015
• Published: 03/23/2017
• Est. Priority Date: 09/22/2015
• Status: Active Grant

• Current Assignee: West Pharma. Services IL, Ltd. (West Pharmaceutical Services Incorporated)
• Original Assignee: Medimop Medical Projects Ltd. (West Pharmaceutical Services Incorporated)
• Inventors: Cabiri, Oz, HEZKIAHU, Ran
• Granted Patent: US 9,987,432 B2
• Time in Patent Office: Days
• CPC Class Codes: A61M 2005/3123 having air entrapping or venting means, e.g. purging channels in pistons
• CPC Class Codes: A61M 5/142 Pressure infusion, e.g. using pumps
• CPC Class Codes: A61M 5/14248 of the skin patch type
• CPC Class Codes: A61M 5/1452 pressurised by means of pistons
• CPC Class Codes: A61M 5/31501 Means for blocking or restricting the movement of the rod or piston A61M5/5013 takes precedence
• CPC Class Codes: A61M 5/31511 Piston or piston-rod constructions, e.g. connection of piston with piston-rod A61M5/5066 takes precedence
• CPC Class Codes: A61M 5/31515 Connection of piston with piston rod
• CPC Class Codes: A61M 5/31565 Administration mechanisms, i.e. constructional features, modes of administering a dose dosing mechanisms for setting a dose A61M5/31533
• CPC Class Codes: A61M 5/31583 based on rotational translation, i.e. movement of piston rod is caused by relative rotation between the user activated actuator and the piston rod
• CPC Class Codes: A61M 5/31586 performed by rotationally moving or pivoted actuator, e.g. an injection lever or handle

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.

Claims

1. An assembly for driving a plunger and 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

a radial element extending from said distal shaft to contact an interior side wall of the reservoir, said element configured and oriented to wedge between said interior wall and said distal shaft when said distal shaft is rotated in said first rotational direction.

2. The assembly of claim 1, wherein said element includes a virtual sprag having a long axis and wherein said long axis intersects said interior side wall.

3. The assembly of claim 2, wherein said long axis intersects said interior side wall at an angle between 91 and 120 degrees from said first rotational direction.

4. The assembly of claim 1, wherein said element includes a virtual beam having a preferred bending direction opposite said first rotational direction.

5. The assembly of claim 1, further comprising:

a plunger interface configured to engage the plunger;

said plunger interface irrotationally interconnecting said distal shaft and the plunger when said plunger interface is engaged to the plunger.

6. The assembly of claim 1, further comprising:

a vent for releasing gas from a space between the element and the plunger.

7. The assembly of claim 1, wherein said radial element is located proximal to said distal end of said distal shaft.

8. The assembly of claim 1, wherein said wedging is longitudinal such that moving said distal shaft distally with respect to said reservoir reduces a normal force between said radial element and said interior wall.

9. The assembly of claim 1, wherein a resistance due to friction between said radial element and said interior wall to movement of said distal shaft in said first rotational direction is higher resistance due to friction between said radial element and said interior wall to movement of said distal shaft in a direction opposite said first rotational direction.

10. The assembly of claim 1, further comprising:

a second friction element extending from a drug delivery device to contact an exterior side wall of the reservoir when said reservoir is inserted into said drug delivery device, said second friction element is configured and oriented to wedge between said exterior wall and said reservoir when said reservoir is rotated in a second rotational direction.

11. The assembly of claim 10, wherein said second rotational direction is opposite said first rotational direction.

12. A method of advancing a plunger in a drug reservoir comprising:

providing a telescoping assembly that extends by rotating a driver in a first direction with respect to a pushing shaft mated to the driver, said pushing shaft including a friction element in contact with a wall of the reservoir;

rotating said driver in said first direction;

wedging said friction element between said pushing shaft and said wall as result of said rotating;

inhibiting rotation of said first direction as a result of said wedging; and

unwedging said friction element to facilitating advancing of said pushing shaft.

13. The method of claim 12, wherein said wedging is substantially the only process impeding rotation of said pushing shaft with respect to the reservoir.

14. The method of claim 12, wherein wedging include increasing normal force.

15. The method of claim 12, further comprising:

reducing a normal force between said friction element and said wall of the reservoir when said pushing shaft moves in a distal direction.

16. The method of claim 12, wherein the drug reservoir includes a plunger, the method further comprising:

reducing a normal force between said friction element and said wall of the reservoir when said pushing shaft pushes distally against said plunger.

17. A drug delivery device comprising:

a housing including a channel;

a drug reservoir fitting into said channel; and

a friction element extending from a housing to said channel to contact an exterior side wall of the reservoir when said reservoir is inserted into said channel, said element configured and oriented to wedge between said exterior wall and said reservoir when said reservoir is rotated in a first rotational direction.

18. The assembly of claim 17, further comprising:

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

a second friction element inhibiting rotation of said shaft with respect to said reservoir.

19. The assembly of claim 17, wherein said channel is cylindrical and includes an opening at one end and wherein said reservoir slides longitudinally through said opening into said channel and wherein said friction element has increased friction resistance to movement in said first rotational direction than to movement in said longitudinal direction.

20. A method of distributing a drug comprising:

supplying a reservoir containing the drug and a distribution device including a channel and a friction element;

inserting said reservoir into longitudinally into said channel; and

wedging said reservoir against said friction element by rotating said reservoir with respect to said device.