Low friction syringe

• US 4,266,557 A
• Filed: 06/29/1979
• Issued: 05/12/1981
• Est. Priority Date: 01/16/1978
• Status: Expired due to Term

• Current Assignee: The Kendall Company (Colgate-Palmolive Company)
• Original Assignee: The Kendall Company (Colgate-Palmolive Company)
• Inventors: Merry, Jack D.
• Primary Examiner(s): Yasko, John D.
• Application Number:
  US06/053,492
• Time in Patent Office: 683 Days
• Field of Search: 128/218 P, 128/218 PA, 128/218 R, 128/234, 128/760, 128/763, 128/276
• US Class Current: 600/576
• CPC Class Codes: A61B 5/15003 for venous or arterial blood
• CPC Class Codes: A61B 5/150236 Pistons, i.e. cylindrical bodies that sit inside the syringe barrel, typically with an air tight seal, and slide in the barrel to create a vacuum or to expel blood
• CPC Class Codes: A61B 5/150244 Rods for actuating or driving the piston, i.e. the cylindrical body that sits inside the syringe barrel, typically with an air tight seal, and slides in the barrel to create a vacuum or to expel blood
• CPC Class Codes: A61B 5/150732 Needle holders, for instance for holding the needle by the hub, used for example with double-ended needle and pre-evacuated tube,
• CPC Class Codes: A61B 5/153 Devices specially adapted for taking samples of venous or arterial blood, e.g. with syringes
• CPC Class Codes: A61M 2005/31521 Pistons with a forward extending skirt at their front end
• CPC Class Codes: A61M 5/31513 Piston constructions to improve sealing or sliding

Abstract

A low friction syringe comprising, a barrel defining a chamber, a plunger having a distal end received in the barrel chamber, and a plug of elastic material having a body portion secured to the distal end of the plunger. The plug has first and second annular flanges respectively extending forwardly and rearwardly from the body portion. The first and second flanges have an enlarged outer annular lip lightly contacting an inner surface of the barrel, and an annular hinge portion adjacent the body portion to permit flexation of the flanges responsive to differential pressures between a cavity intermediate the flanges and either the chamber or the atmosphere. The flanges also permit free movement of the plug in the chamber under relatively low friction between the plug and the syringe barrel.

Claims

1. A low friction syringe, comprising:

a barrel having an inner surface defining a chamber;

a plunger having a distal end received in the barrel chamber; and

a plug of elastic material received in said chamber and having a body portion secured to said distal end of the plunger, said plug having a first annular flange extending forwardly from said body portion, said first flange having an enlarged outer annular lip lightly contacting the inner surface of said barrel, and an annular hinge portion adjacent said body portion of reduced thickness relative the thickness of said lip, said plug having a second annular flange extending rerwardly from the body portion, said second flange having an enlarged outer annular lip lightly contacting the inner surface of said barrel, and an annular hinge portion adjacent said body portion of reduced thickness relative the thickness of the second flange lip, said first and second flanges defining an annular cavity intermediate the body portion and the barrel, said first flange flexing against the inner surface of the barrel responsive to a slightly greater pressure in the chamber relative the cavity during forward movement of the plunger in the barrel, and said first flange flexing about its hinge away from the inner surface of the barrel responsive to a slightly less pressure in the chamber relative the cavity and said second flange flexing against the inner surface of the barrel responsive to a slightly less pressure in the communicating chamber and cavity relative the pressure rearward the plug during rearward movement of the plunger in the barrel, said plug having a width between inner ends of said hinge portions of the first and second flanges substantially greater than the thickness of the first and second flanges, such that said plug flexes substantially only in said flange portions and the second flange contacts the barrel during said forward and rearward movements of the plunger in the barrel.

2. The syringe of claim 1 wherein said barrel and plunger are constructed from a plastic material.

3. The syringe of claim 1 wherein said barrel includes an enlarged section adjacent a rearward end of the barrel having an internal diameter slightly larger than the outer diameter of the first and second flanges.