Medical syringe

• US 6,432,089 B1
• Filed: 06/21/2000
• Issued: 08/13/2002
• Est. Priority Date: 06/21/2000
• Status: Expired due to Term

• Current Assignee: Bayer Healthcare LLC (Bayer AG), Schering Ag (Merck & Co., Inc.)
• Original Assignee: Medrad Incorporated (Bayer AG)
• Inventors: Hitchins, Mark, Kakimi, Mitsuru
• Primary Examiner(s): Casler, Brian L.
• Assistant Examiner(s): RODRIGUEZ, CRIS LOIREN
• Application Number:
  US09/598,628
• Time in Patent Office: 783 Days
• Field of Search: 604/222, 604/230, 604/218, 604/187, 604/193, 604/215, 604/219-221, 604/228, 604/229, 222/135, 222/386
• US Class Current: 604/218
• CPC Class Codes: A61M 2005/14553 comprising a pressure jacket
• CPC Class Codes: A61M 5/007 for contrast media
• 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 5/31515 Connection of piston with piston rod

Abstract

A medical syringe 2 includes a cylindrical syringe body 3 and a plunger 4 fitted in the syringe body 3 for injecting a liquid agent filled in the syringe body 3 from the syringe body 3 into the vascular system of the human body by advancing the plunger 4 relative to the syringe body 3. The plunger 4 comprising a plunger body 5 and an elastic cover 9 fitted over the plunger body 5 from the front. The plunger body 5 is provided with a backplate 62 at a rear end thereof, the backplate 62 having an annular groove 68 forwardly opened and formed in a front surface outer peripheral portion thereof. The portion of the elastic cover 9 to be rearwardly stretched by the advance of the plunger 4 is allowed to ingress into the annular groove 68 for escape.

Claims

1. A syringe comprising:

a cylindrical syringe body (3); and

a plunger (4) movably disposed within the syringe body (3) for injecting a liquid agent filled in the syringe body (3) from the syringe body (3) into the vascular system of a human body or animal, the plunger (4) comprising a plunger body (5) and an elastic cover (9) fitted over the plunger body from the front, the plunger body (5) comprising a backplate (62) at a rear end thereof, the backplate (62) defining an annular groove (68) forwardly opened and formed in a front surface thereof in the vicinity of an outer periphery thereof, the elastic cover (9) comprising a portion to be rearwardly stretched by friction with the syringe body (3) during advancement of the plunger (4) and operable to ingress into the annular groove (68).

2. A syringe according to claim 1 wherein the elastic cover (9) further comprises an annular ridge (95) formed on a rear end face thereof and concentric with the elastic cover.

3. A syringe according to claim 1 wherein the backplate (62) further comprises opposite side faces (68a), (68b) defining the annular groove (68) and inclined to give the groove a width decreasing toward a bottom thereof.

4. A syringe according to claim 1 wherein the elastic cover (9) is molded from a composition having incorporated therein paraffin wax, or polyethylene.

5. A syringe according to claim 1 wherein the syringe body (3) is prefilled with the liquid agent to be injected, sealed by the plunger (4) at a rear portion thereof and provided at a front portion thereof with a nozzle (30) temporarily sealed so as not to permit leakage of the liquid agent.