Plunger systems

• US 6,984,222 B1
• Filed: 11/09/1999
• Issued: 01/10/2006
• Est. Priority Date: 11/12/1996
• Status: Expired due to Fees

• Current Assignee: Bayer Healthcare LLC (Bayer AG)
• Original Assignee: Medrad Incorporated (Bayer AG)
• Inventors: Rhinehart, Edward J., Reilly, David M., Hitchins, Mark W., McCoppin, Anthony S., Masarik, Robert J., Dufalla, Thomas L.
• Primary Examiner(s): MENDEZ, MANUEL A
• Application Number:
  US09/436,612
• Time in Patent Office: 2,254 Days
• Field of Search: 604/218, 604/151, 604/152, 604/131, 604/232, 604/155, 604/156, 604/219
• US Class Current: 604/218
• CPC Class Codes: A61M 5/14546 Front-loading type injectors
• CPC Class Codes: A61M 5/14566 with a replaceable reservoir for receiving a piston rod of the pump
• CPC Class Codes: A61M 5/1458 Means for capture of the plunger flange

Abstract

The plunger systems for use in an injector-actuated syringe of the present invention include a dynamic wedge seal which improves the sealing engagement between the plunger cover and syringe barrel, and flexible capture members extending from the rear surface of the plunger which permit the engagement and disengagement of the plunger from the injector drive means at any plunger position within the syringe. Further, the plunger systems include a contrast saving tip which expells the injection liquid from the syringe tip.

Claims

1. A plunger for use in a syringe comprising a body portion having an inner wall, a discharge end and a transition region defined between the body portion and the discharge end, the plunger comprising:

a base comprising a side portion that is tapered so that the diameter of the side portion of the base decreases from a rearward axial position to a forward axial position thereof; and

a plunger surface disposed on at least a portion of the base, the plunger surface comprising a seal portion operably associated with the side portion of the base, the seal portion comprising an exterior surface in contact with the inner wall of the syringe and an inner wall that is tapered so that the diameter of the seal portion inner wall decreases from a rearward axial position to a forward axial position thereof,

wherein increases in pressure caused by movement of the plunger in the syringe compresses the seal portion between the inner wall of the syringe and the side portion of the base to create a dynamic seal between the seal portion and the inner wall of the syringe.

2. The plunger of claim 1 wherein an angle of taper of the side portion and an angle of taper of the seal portion are approximately equal.

3. The plunger of claim 2 wherein the angle of taper of the side portion and the angle of taper of the seal portion are in the range of approximately 3°

to approximately 15°

.

4. The plunger of claim 3 wherein the angle of taper of the side portion and the angle of taper of the seal portion are in the range of approximately 4°

to approximately 10°

.

5. The plunger of claim 1 wherein the plunger surface further comprises a forward portion having a shape generally complementary to that of the transition region of the syringe.

6. The plunger of claim 5 wherein the forward portion has a generally conical shape.

7. The plunger of claim 5 wherein the forward portion has a generally hemispherical shape.

8. A syringe comprising:

a body portion;

a discharge end;

a transition region defined between the body portion and the discharge end; and

a plunger movably disposed within at least the body portion, the plunger comprising a base comprising a side portion that is tapered so that the diameter of the side portion of the base decreases from a rearward axial position to a forward axial position thereof and a plunger surface disposed on at least a portion of the base, the plunger surface comprising a seal portion operably associated with the side portion of the base, the seal portion comprising an exterior surface in contact with the inner wall of the syringe and an inner wall that is tapered so that the diameter of the seal portion inner wall decreases from a rearward axial position to a forward axial position thereof;

wherein increases in pressure caused by movement of the plunger in the syringe compresses the seal portion between the inner wall of the syringe and the side portion of the base to create a dynamic seal between the seal portion and the inner wall of the syringe.

9. The syringe of claim 8 wherein an angle of taper of the side portion and an angle of taper of the seal portion are approximately equal.

10. The syringe of claim 9 wherein the angle of taper of the side portion and the angle of taper of the seal portion are in the range of approximately 3°

to approximately 15°

.

11. The syringe of claim 10 wherein the angle of taper of the side portion and the angle of taper of the seal portion are in the range of approximately 4°

to approximately 10°

.

12. The syringe of claim 8 wherein the plunger surface further comprises a forward portion having a shape generally complementary to that of the transition region of the syringe.

13. The syringe of claim 12 wherein the forward portion has a generally conical shape.

14. The syringe of claim 8 wherein the plunger surface further comprises a protruding member at a forward end thereof, the protruding member being adapted to enter the discharge end of the syringe when the plunger is advanced to expel liquid therefrom.