Patent ID: 7537582
Filing Date: 2009-05-26
Classification: A61M

Abstract:
1. An operable syringe assembly having passive disabling structure composing: a barrel including a cylindrical side wall having an inside surface defining a chamber for retaining fluid, an open proximal end and a distal end including a distal wall having a passageway therethrough in fluid communication with said chamber, an annular discontinuity extending 360° around said inside surface of said barrel; an elongate hollow plunger rod having a proximal end, an open distal end and an interior surface, at least one recess in said interior surface at said distal end of said plunger rod, said recess having a distal face, at least one detent on said interior surface at said distal end of said plunger rod; a stopper including a circular shaped sealing element having a peripheral surface forming a seal with said inside surface of said barrel, a boss member projecting proximally from said sealing element, at least one boss detent on said boss, at least one cantilevered arm extending proximally from said sealing element, said at least one cantilevered arm having an outwardly extending rib near its free end, said rib being sized to fit within said recess in said plunger rod; a locking element including a central body portion having an aperture therethrough, at least one cantilevered leg extending distally outwardly from said body portion, and at least one finger element extending proximally inwardly from said aperture, said at least one leg having a sharp free end directed outwardly for engaging said inside surface of said barrel; said locking element being positioned with said sharp free end contacting said interior surface of said plunger rod proximally of said at least one detent, said boss member being positioned in said aperture of said locking element wherein said at least one finger element is contacting said boss proximally of said at least one boss detent, and said outwardly extending rib being positioned in said recess of said plunger rod, so that applying a proximally directed force to said plunger rod while holding said barrel causes said plunger rod to move proximally with respect to said stopper until said free end of said cantilevered leg moves distally along said inner surface of said plunger rod to said at least one detent and said outwardly extending rib on said cantilevered arm engages said distal face of said recess to move said stopper in a proximal direction for a selected distance, and subsequently applying a distally directed force to said plunger rod to discharge fluid from said chamber through said passageway causes said plunger rod to move in a distal direction along with said locking element due to its engagement with said at least one detent until said finger element of said locking element rides over said at least one boss detent and said discontinuity in said barrel and into contact with said at least one boss detent and said plunger rod contacts said stopper to move said stopper distally to discharge fluid from said chamber, after which applying a proximally directed force to said plunger rod will cause said plunger rod to move proximally until said free end of said cantilevered leg moves distally along said inner surface of said barrel so that said sharp end engages said discontinuity on said inside of said barrel to help prevent proximal movement of said stopper to render said syringe assembly unusable.