Drive device for a piston in a container containing a liquid product

• US 20070093751A1
• Filed: 09/14/2006
• Published: 04/26/2007
• Est. Priority Date: 09/30/2005
• Status: Active Grant

• Current Assignee: Roche Diabetes Care Inc. (Roche Holding AG)
• Original Assignee: Roche Diagnostics Operations Incorporated (Roche Holding AG)
• Inventors: Harttig, Herbert
• Granted Patent: US 7,922,694 B2
• Time in Patent Office: Days
• US Class Current: 604/131
• CPC Class Codes: A61M 2005/3151 by friction
• CPC Class Codes: A61M 2205/0266 Shape memory materials
• CPC Class Codes: A61M 5/14526 the piston being actuated by fluid pressure
• CPC Class Codes: A61M 5/14566 with a replaceable reservoir for receiving a piston rod of the pump
• CPC Class Codes: A61M 5/31511 Piston or piston-rod constructions, e.g. connection of piston with piston-rod A61M5/5066 takes precedence

Abstract

A drive device for a piston in a container containing a liquid comprises a first segment positioned between a second segment and an outlet of the container. The first and second segments each have a first shape in which the respective segment is clamped between lateral walls of the container and a second shape in which the respective segment is released from the lateral walls. A first actuator is configured to vary the first segment between its first and second shapes, and the first segment is in its first shape when the first actuator is inactive. A second actuator is configured to vary the second segment between its first and second shapes, and the second segment is in its second shape when the second actuator is inactive. A connecting segment connects the first segment to the second segment and has an actively variable connecting length.

Claims

1-10. -10. (canceled)

11. A drive device for a piston in a container containing a liquid product, the container having limiting lateral walls that extend in a longitudinal direction toward an outlet for the liquid product, the drive device comprising:

a first segment having an actively variable shape, the first segment having a first shape in which the first segment is clamped between the lateral walls of the container and having a second shape in which the first segment is released from the lateral walls,

a first paraffin actuator configured to actively vary the first segment between its first and second shapes,

a second segment having an actively variable shape, the second segment having a first shape in which the second segment is clamped between the lateral walls of the container and having a second shape in which the second segment is released from the lateral walls, the first segment being positioned between the second segment and the outlet,

a second paraffin actuator configured to actively vary the second segment between its first and second shapes, and

a connecting segment connecting the first segment to the second segment, the connecting segment having an actively variable connecting length.

12. The drive device of claim 11 wherein the connecting segment has a first connecting length and a second connecting length that is longer than the first connecting length.

13. The drive device of claim 12 wherein the connecting segment is a third actuator having a length, the third actuator configured to actively vary its length between the first and second connecting lengths.

14. The drive device of claim 12 further comprising a third actuator configured to actively vary the connecting length of the connecting segment between the first and second connecting lengths.

15. The drive device of claim 11 wherein the first segment is rigidly connected to the piston.

16. The drive device of claim 11 wherein the first segment is integral with the piston.

17. The drive device of claim 11 wherein the first segment assumes its second shape when the first paraffin actuator is inactive,

and wherein the second segment assumes its first shape when the second paraffin actuator is inactive.

18. The drive device of claim 11 wherein the container has a circular cross section,

wherein the first segment comprises a first clamping ring that is clamped in its first shape to an inner wall of the container and is released from the inner wall in its second shape,

and wherein the second segment comprises a second clamping ring that is clamped in its first shape to the inner wall of the container and is released from the inner wall in its second shape.

19. The drive device of claim 18 wherein the first clamping ring defines a first ring diameter that can be varied by activating the first paraffin actuator,

and wherein the second clamping ring defines a second ring diameter that can be varied by activating the second paraffin actuator.

20. The drive device of claim 19 wherein the first clamping ring comprises a first open ring with two tongues projecting into the first open ring,

and wherein the first paraffin actuator is positioned between the two tongues of the first open ring and has a thickness that is actively variable.

21. The drive device of claim 20 wherein the first paraffin actuator is actively variable between first and second thicknesses, the first paraffin actuator acting on the two tongues of the first open ring with its first thickness to control the first ring diameter of the first clamping ring to clamp the first clamping ring to the inner wall of the container,

and wherein the first paraffin actuator has a second thickness that is less than its first thickness, the first paraffin actuator acting on the two tongues with its second thickness to control the first ring diameter of the first clamping ring to release the first clamping ring from the inner wall of the container.

22. The drive device of claim 21 wherein the first paraffin actuator assumes its first thickness when inactive and assumes its second thickness when activated.

23. The drive device of claim 19 wherein the second segment comprises:

a baseplate,

a second open ring with two tongues projecting into the second open ring, one of the two tongues of the second open ring being attached to the baseplate, and

a thrust bearing attached to the baseplate adjacent to the other of the two tongues of the second open ring,

wherein the second paraffin actuator is positioned between the thrust bearing and the other of the two tongues of the second open ring, the second paraffin actuator having a thickness that is actively variable.

24. The drive device of claim 23 wherein the second paraffin actuator is actively variable between first and second thicknesses, the second paraffin actuator acting on the thrust bearing and the other of the two tongues of the second open ring with its first thickness to control the second ring diameter of the second clamping ring to clamp the second clamping ring to the inner wall of the container,

and wherein the second paraffin actuator has a second thickness that is greater than its first thickness, the second paraffin actuator acting on the thrust bearing and the other of the two tongues of the second open ring with its second thickness to control the second ring diameter of the second clamping ring to release the second clamping ring from the inner wall of the container.

25. The drive device of claim 24 wherein the second paraffin actuator assumes its first thickness when active and assumes its second thickness when inactive.

26. A drive device for a piston in a container containing a liquid product, the container having limiting lateral walls that extend in a longitudinal direction toward an outlet for the liquid product, the drive device comprising:

a first segment having an actively variable shape, the first segment having a first shape in which the first segment is clamped between the lateral walls of the container and having a second shape in which the first segment is released from the lateral walls,

a first actuator configured to actively vary the first segment between its first and second shapes, the first segment being in its first shape when the first actuator is inactive,

a second segment having an actively variable shape, the second segment having a first shape in which the second segment is clamped between the lateral walls of the container and having a second shape in which the second segment is released from the lateral walls, the first segment being positioned between the second segment and the outlet,

a second actuator configured to actively vary the second segment between its first and second shapes, the second actuator being in its second shape when the second actuator is inactive, and

a connecting segment connecting the first segment to the second segment, the connecting segment having an actively variable connecting length.

27. The drive device of claim 26 wherein the first segment is rigidly connected to the piston.

28. The drive device of claim 26 wherein the first segment is integral with the piston.

29. The drive device of claim 26 wherein the first segment assumes its second shape when the first actuator is activated,

and wherein the second segment assumes its first shape when the second actuator is activated.

30. The drive device of claim 26 wherein the connecting segment has a first connecting length and a second connecting length that is longer than the first connecting length.

31. The drive device of claim 30 wherein the connecting segment is a third actuator having a length, the third actuator configured to actively vary its length between the first and second connecting lengths.

32. The drive device of claim 30 further comprising a third actuator configured to actively vary the connecting length of the connecting segment between the first and second connecting lengths.

33. The drive device of claim 26 wherein the container has a circular cross section,

and wherein the first segment comprises a first clamping ring,

and wherein the second segment comprises a second clamping ring.

34. The drive device of claim 33 wherein the first clamping ring defines a first ring diameter that can be varied by activating the first actuator,

and wherein the second clamping ring defines a second ring diameter that can be varied by activating the second actuator.

35. The drive device of claim 34 wherein the first clamping ring comprises a first open ring with two tongues projecting into the first open ring,

and wherein the first actuator comprises a first paraffin actuator positioned between the two tongues, the first paraffin actuator having a thickness that is actively variable.

36. The drive device of claim 35 wherein the first paraffin actuator is actively variable between first and second thicknesses, the first paraffin actuator acting on the two tongues of the first clamping ring with its first thickness to control the first ring diameter of the first clamping ring to clamp the first clamping ring to the inner wall of the container,

and wherein the first paraffin actuator has a second thickness that is less than its first thickness, the first paraffin actuator acting on the two tongues with its second thickness to control the first ring diameter of the first clamping ring to release the first clamping ring from the inner wall of the container.

37. The drive device of claim 36 wherein the first paraffin actuator assumes its first thickness when inactive and assumes its second thickness when activated.

38. The drive device of claim 33 wherein the second segment further comprises:

a baseplate,

a second open ring with two tongues projecting into the second open ring, one of the two tongues of the second open ring being attached to the baseplate, and

a thrust bearing attached to the baseplate adjacent to the other of the two tongues of the second open ring,

wherein the second actuator comprises a second paraffin actuator positioned between the thrust bearing and the other of the two tongues of the second open ring, the second paraffin actuator having a thickness that is actively variable.

39. The drive device of claim 38 wherein the second paraffin actuator is actively variable between first and second thicknesses, the second paraffin actuator acting on the thrust bearing and the other of the two tongues of the second open ring with its first thickness to control the second ring diameter of the second clamping ring to clamp the second clamping ring to the inner wall of the container,

and wherein the second paraffin actuator has a second thickness that is greater than its first thickness, the second paraffin actuator acting on the thrust bearing and the other of the two tongues of the second open ring with its second thickness to control the second ring diameter of the second clamping ring to release the second clamping ring from the inner wall of the container.

40. The drive device of claim 39 wherein the second paraffin actuator assumes its first thickness when active and assumes its second thickness when inactive.

41. A method for dosing a liquid product by displacing a piston in a container containing the liquid product via a drive device, wherein the container has limiting lateral walls extending in a longitudinal direction towards a liquid product outlet, and the drive device comprises a first segment positioned between the outlet and a second segment and a connecting segment connecting the first and second segments together, the method comprising:

a) normally clamping the first segment between the lateral walls,

b) normally releasing second segment from the lateral walls to allow movement of the second segment relative to the lateral walls,

c) clamping the second segment between the lateral walls by actively expanding the shape of the second segment,

d) releasing the first segment from the lateral walls by actively contracting the shape of the first segment,

e) increasing the length of the connecting segment to displace the first segment relative to the second segment in the direction of the outlet,

f) clamping the first segment between the lateral walls by relaxing the shape of the first segment to its normal state of being clamped between the lateral walls,

g) releasing the second segment from the lateral walls by relaxing the shape of the second segment to its normal state of being released from the lateral walls, and

h) reducing the length of the connecting segment to displace the second segment relative to the first segment in the direction of the outlet.

42. The method of claim 41 further comprising repeatedly executing sequentially steps c)-h) a number of times to dose a predefined quantity of the liquid product from the container.