Syringe actuation device

• US 5,800,405 A
• Filed: 01/30/1997
• Issued: 09/01/1998
• Est. Priority Date: 12/01/1995
• Status: Expired due to Term

• Current Assignee: Camedi-sis, LLC
• Original Assignee: I-Flow Corporation (Kimberly-Clark Corporation)
• Inventors: McPhee, Charles J.
• Primary Examiner(s): YASKO JR, JOHN D
• Application Number:
  US08/794,211
• Time in Patent Office: 579 Days
• Field of Search: 604/218, 604/246, 604/156, 604/132-137, 604/187, 604/131
• US Class Current: 604/218
• CPC Class Codes: A61M 5/1454 spring-actuated, e.g. by a clockwork
• CPC Class Codes: A61M 5/1456 with a replaceable reservoir comprising a piston rod to be moved into the reservoir, e.g. the piston rod is part of the removable reservoir

Abstract

A syringe actuation device includes a housing containing a spring-biased piston that applies an actuation force to a syringe plunger inserted into the housing. A pivoting mechanism causes the piston to pivot with respect to the longitudinal axis of the housing as the piston moves along that axis to actuate the plunger, whereby the axially-directed component of the force applied by the piston to the plunger remains substantially constant throughout the stroke of the piston. In one embodiment, the device comprises an internally-threaded outer sleeve having a longitudinal opening for receiving a pre-filled syringe with an extended plunger and a distal opening through which the syringe barrel extends, and an externally-threaded cylinder, containing the piston, that threads into the proximal end of the sleeve so as to bring the piston to bear against the plunger. The pivoting mechanism comprises a tapered internal diameter of the cylinder, and a sloped spring seat on the piston. In another embodiment, the device comprises a housing that contains a piston biased by a pair of springs, and a sleeve that receives a syringe barrel, with the plunger of the syringe extending from the proximal end of the sleeve. The proximal end of the sleeve is inserted into the housing through an opening in the distal end wall of the housing, so that the plunger seats against the piston. The pivoting mechanism comprises a narrowing internal housing width and springs of unequal spring constant and/or length.

Claims

1. A device for applying an axially-directed actuation force to a syringe plunger, of the type including a force-applying mechanism engageable with the plunger to apply the actuation force thereto, characterized by the force applying mechanism having a first position at which the magnitude of the total force applied to the plunger is at a maximum value but the axially-directed actuation force is less than the total force applied to the plunger, and a second position at which the magnitude of the total force applied to the plunger is less than its maximum value and the axially-directed force is approximately equal to the total force applied to the plunger, wherein the force-applying mechanism comprises:

a housing having a proximal end and a distal end with an opening dimensioned to receive the plunger;

a piston disposed for longitudinal movement within the housing between a proximal position and a distal position, the piston being seatable against the plunger when the plunger is received in the housing through the opening in the distal end;

first and second springs disposed between the piston and the proximal end of the housing so as to bias the piston toward its distal position; and

pivoting means, operative on the piston, for canting the piston with respect to the longitudinal axis of the housing when the piston is in its proximal position, and for causing the piston to pivot as it moves toward its distal position until the piston is oriented substantially coaxially with the longitudinal axis when the piston is at its distal position.

2. The device of claim 1, wherein the pivoting means comprises an internal width of the housing that narrows from the proximal end to the distal end.

3. The device of claim 2, wherein the pivoting means further comprises the first spring having a larger spring constant than the second spring.

4. The device of claim 2, wherein the pivoting means further comprises the first spring having a longer length than the second spring.

5. The device of claim 2, wherein the piston comprises:

an open distal end dimensioned to receive the plunger; and

a pair of flanges extending outwardly from opposite sides of the open distal end of the piston, each of the flanges providing a distal seat for one of the springs.

6. The device of claim 3, wherein the piston comprises:

an open distal end dimensioned to receive the plunger; and

a pair of flanges extending outwardly from opposite sides of the open distal end of the piston, each of the flanges providing a distal seat for one of the springs.

7. The device of claim 4, wherein the piston comprises:

an open distal end dimensioned to receive the plunger; and

a pair of flanges extending outwardly from opposite sides of the open distal end of the piston, each of the flanges providing a distal seat for one of the springs.

8. The device of claim 5, further comprising:

a retention element extending into the housing from the distal end opening and dimensioned to be slidably received in the open distal end of the piston; and

a hollow sleeve internally dimensioned to receive a syringe and having an open proximal end configured to engage the retention element through the distal end opening;

whereby, when a syringe is installed in the sleeve with the plunger extending from the distal end of the sleeve, the engagement of the sleeve with the retention element brings the plunger to bear against the proximal piston end so as to urge the piston toward its proximal position.

9. The device of claim 8, further comprising a locking mechanism, operable between the sleeve and the retention element, that substantially prevents relative movement between the sleeve and the retention element in response to the force applied by the piston to the plunger.

10. The device of claim 9, wherein the locking mechanism comprises:

internal threads in the retention element; and

external threads on the sleeve.

11. The device of claim 6, further comprising:

a retention element extending into the housing from the distal end opening and dimensioned to be slidably received in the open distal end of the piston; and

a hollow sleeve internally dimensioned to receive a syringe and having an open proximal end configured to engage the retention element through the distal end opening;

whereby, when a syringe is installed in the sleeve with the plunger extending from the distal end of the sleeve, the engagement of the sleeve with the retention element brings the plunger to bear against the proximal piston end so as to urge the piston toward its proximal position.

12. The device of claim 11, further comprising a locking mechanism, operable between the sleeve and the retention element, that substantially prevents relative movement between the sleeve and the retention element in response to the force applied by the piston to the plunger.

13. The device of claim 12, wherein the locking mechanism comprises:

internal threads in the retention element; and

external threads on the sleeve.

14. The device of claim 7, further comprising:

a retention element extending into the housing from the distal end opening and dimensioned to be slidably received in the open distal end of the piston; and

a hollow sleeve internally dimensioned to receive a syringe and having an open proximal end configured to engage the retention element through the distal end opening;

whereby, when a syringe is installed in the sleeve with the plunger extending from the distal end of the sleeve, the engagement of the sleeve with the retention element brings the plunger to bear against the proximal piston end so as to urge the piston toward its proximal position.

15. The device of claim 14, further comprising a locking mechanism, operable between the sleeve and the retention element, that substantially prevents relative movement between the sleeve and the retention element in response to the force applied by the piston to the plunger.

16. The device of claim 15, wherein the locking mechanism comprises:

internal threads in the retention element; and

external threads on the sleeve.

17. A device for actuating a syringe, wherein the syringe includes a barrel and a plunger movable axially within the barrel, the device comprising:

a housing having a closed proximal end and a distal end with an opening therein dimensioned to receive the plunger;

a retention element extending into the housing from the distal end opening;

a piston disposed for longitudinal movement within the housing between a proximal position and a distal position, the piston having a proximal end and an open distal end dimensioned to slidingly receive the retention element when the piston is in its distal position;

first and second springs disposed within the housing between the piston and the proximal end of the housing so as to bias the piston toward its distal position; and

an externally-threaded sleeve internally dimensioned to receive a syringe and externally dimensioned to be received within the opening in the distal end of the housing and selectively threaded into and out of the retention element, the sleeve having an open proximal end through which the plunger of the syringe extends when a syringe is installed in the sleeve;

whereby, when the sleeve is threaded into the retention element through the opening in the distal end of the housing with a syringe installed in the sleeve and the plunger of the syringe extending proximally through the open proximal end of the sleeve, the plunger of the syringe bears against the proximal end of the piston so as to urge the piston toward its proximal position.

18. The device of claim 17, further comprising:

pivoting means, operative on the piston, for canting the piston with respect to the longitudinal axis of the housing when the piston is in its proximal position, and for causing the piston to pivot as it moves toward its distal position until the piston is oriented substantially coaxially with the longitudinal axis when the piston is at its distal position.

19. The device of claim 18, wherein the pivoting means comprises an internal width of the housing that narrows from the proximal end to the distal end.

20. The device of claim 19, wherein the pivoting means further comprises the first spring having a larger spring constant than the second spring.

21. The device of claim 19, wherein the pivoting means further comprises the first spring having a longer length than the second spring.

22. The device of claim 17, wherein the piston comprises:

a pair of flanges extending outwardly from opposite sides of the open distal end of the piston, each of the flanges providing a distal seat for one of the springs.

23. The device of claim 18, wherein the piston comprises:

a pair of flanges extending outwardly from opposite sides of the open distal end of the piston, each of the flanges providing a distal seat for one of the springs.

24. The device of claim 19, wherein the piston comprises:

a pair of flanges extending outwardly from opposite sides of the open distal end of the piston, each of the flanges providing a distal seat for one of the springs.

25. The device of claim 20, wherein the piston comprises:

a pair of flanges extending outwardly from opposite sides of the open distal end of the piston, each of the flanges providing a distal seat for one of the springs.

26. The device of claim 21, wherein the piston comprises:

a pair of flanges extending outwardly from opposite sides of the open distal end of the piston, each of the flanges providing a distal seat for one of the springs.

27. An infusion system, comprising:

a hollow sleeve having open proximal and distal ends;

a housing having a proximal end and a distal end with an opening through which the proximal end of the hollow sleeve is received in the housing;

a syringe having an outlet tip and a plunger, and installed in the sleeve with the outlet tip extending from the distal end of the sleeve and the plunger extending from the proximal end of the sleeve;

a piston that bears against the plunger and that is disposed for longitudinal movement within the housing between a proximal position and a distal position;

first and second springs disposed between the piston and the proximal end of the housing so as to bias the piston toward its distal position, thereby applying an axially-directed force component to the plunger; and

means for maintaining the axially-directed force component substantially constant as the piston moves from its proximal position to its distal position.

28. The system of claim 27, wherein the means for maintaining comprises:

pivoting means, operative on the piston, for canting the piston with respect to the longitudinal axis of the housing when the piston is in its proximal position, and for causing the piston to pivot as it moves toward its distal position until the piston is oriented substantially coaxially with the longitudinal axis when the piston is at its distal position.

29. The system of claim 28, wherein the pivoting means comprises an internal width of the housing that narrows from the proximal end to the distal end.

30. The system of claim 29, wherein the pivoting means further comprises the first spring having a larger spring constant than the second spring.

31. The system of claim 29, wherein the pivoting means further comprises the first spring having a longer length than the second spring.

32. The system of claim 27, wherein the piston comprises:

an open distal end dimensioned to receive the plunger; and

a pair of flanges extending outwardly from opposite sides of the open distal end of the piston, each of the flanges providing a distal seat for one of the springs.

33. The system of claim 28, wherein the piston comprises:

an open distal end dimensioned to receive the plunger; and

a pair of flanges extending outwardly from opposite sides of the open distal end of the piston, each of the flanges providing a distal seat for one of the springs.

34. The system of claim 29, wherein the piston comprises:

an open distal end dimensioned to receive the plunger; and

a pair of flanges extending outwardly from opposite sides of the open distal end of the piston, each of the flanges providing a distal seat for one of the springs.

35. The system of claim 30, wherein the piston comprises:

an open distal end dimensioned to receive the plunger; and

a pair of flanges extending outwardly from opposite sides of the open distal end of the piston, each of the flanges providing a distal seat for one of the springs.

36. The system of claim 31, wherein the piston comprises:

an open distal end dimensioned to receive the plunger; and

a pair of flanges extending outwardly from opposite sides of the open distal end of the piston, each of the flanges providing a distal seat for one of the springs.

37. The system of claim 32, further comprising:

a retention element extending into the housing from the distal end opening, externally dimensioned to be slidably received in the open distal end of the piston, and internally dimensioned to receive the sleeve.

38. The system of claim 37, further comprising a locking mechanism, operable between the sleeve and the retention element, that substantially prevents relative movement between the sleeve and the retention element in response to the axially-directed force component.

39. The system of claim 38, wherein the locking mechanism comprises:

internal threads in the retention element; and

external threads on the sleeve.

40. The system of claim 33, further comprising:

a retention element extending into the housing from the distal end opening, externally dimensioned to be slidably received in the open distal end of the piston, and internally dimensioned to receive the sleeve.

41. The system of claim 40, further comprising a locking mechanism, operable between the sleeve and the retention element, that substantially prevents relative movement between the sleeve and the retention element in response to the force applied by the piston to the plunger.

42. The system of claim 41, wherein the locking mechanism comprises:

internal threads in the retention element; and

external threads on the sleeve.

43. The system of claim 34, further comprising:

a retention element extending into the housing from the distal end opening externally dimensioned to be slidably received in the open distal end of the piston, and internally dimensioned to receive the sleeve.

44. The system of claim 43, further comprising a locking mechanism, operable between the sleeve and the retention element, that substantially prevents relative movement between the sleeve and the retention element in response to the force applied by the piston to the plunger.

45. The system of claim 44, wherein the locking mechanism comprises:

internal threads in the retention element; and

external threads on the sleeve.

46. The system of claim 35, further comprising:

a retention element externally dimensioned to be slidably received in the open distal end of the piston, and internally dimensioned to receive the sleeve.

47. The system of claim 46, further comprising a locking mechanism, operable between the sleeve and the retention element, that substantially prevents relative movement between the sleeve and the retention element in response to the force applied by the piston to the plunger.

48. The system of claim 47, wherein the locking mechanism comprises:

internal threads in the retention element; and

external threads on the sleeve.

49. The system of claim 36, further comprising:

a retention element externally dimensioned to be slidably received in the open distal end of the piston, and internally dimensioned to receive the sleeve.

50. The system of claim 49, further comprising a locking mechanism, operable between the sleeve and the retention element, that substantially prevents relative movement between the sleeve and the retention element in response to the force applied by the piston to the plunger.

51. The system of claim 50, wherein the locking mechanism comprises:

internal threads in the retention element; and

external threads on the sleeve.