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Sequential stopper

  • US 5,713,857 A
  • Filed: 06/28/1996
  • Issued: 02/03/1998
  • Est. Priority Date: 06/28/1996
  • Status: Expired due to Term
First Claim
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1. A stopper useful for sequential delivery of contents held in the barrel of a syringe and for reducing a quantity of the contents remaining in the barrel subsequent to delivery, comprising:

  • a piston-like stopper body for slidable fluid-tight engagement with an inside surface of the barrel, said body having a generally cylindrical side wall with a distal end, a proximal end and a longitudinal axis therethrough;

    an elongate hollow chamber disposed within said body, said hollow chamber having a distal end, a proximal end and a width;

    at least one circumferential sealing element circumferentially disposed about the cylindrical side wall of the stopper body for sealing engagement with the inside surface of the syringe barrel;

    a pair of longitudinal sealing elements longitudinally disposed along the side wall of the body in parallel relation to the longitudinal axis for sealing engagement with the inside surface of the syringe barrel, said pair of longitudinal sealing elements separated along the sidewall by a distance at least equal to the width of the hollow chamber;

    a recessed surface provided on the cylindrical side wall of the stopper body, said recessed surface located adjacent the proximal end of the stopper body and between the pair of longitudinal sealing elements; and

    a distally directed, conically-shaped projection located on the distal end of the body, the conically-shaped projection having a channel communicating with a portion of the sidewall located between the pair of longitudinal sealing elements,wherein in response to fluid pressure exerted upon the proximal end of the body, said recessed surface will allow the portion of side wall located between the pair of longitudinal sealing elements to collapse towards said hollow chamber, said longitudinal sealing elements themselves remaining in fluid tight contact with the syringe barrel, to provide a fluid conduit between the proximal and distal ends of the body limited to that portion of the sidewall between the longitudinal sealing elements to direct substantially all of the fluid held proximally of the body to the distal end of the body, and wherein the channel of said conically shaped projection cooperates with said fluid conduit to expel from the syringe barrel substantially all of the fluid directed to the distal end of the body.

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