Syringe with useless mechanism

摘要

A syringe assembly comprising: a cylinder (520) that includes a cylindrical side wall (524) having an inner surface (526) with a first width of the cross section defining a chamber (528) for fluid retention, an open proximal end (529) 5 and a distal end (521) that includes a distal wall (522) having an opening therethrough in fluid communication with said chamber (528), said side wall (524) includes a rib (510) of said adjacent proximal end (529) defining a second width of the cross section that is smaller than the first width of the cross section; an elongated plunger rod (540) that includes a proximal end (549), a distal end (541), and a main body (544) extending between the proximal end and the distal end (549, 541), the stem of piston (540) is distally and proximally movable within said chamber (528), the proximal end (549) includes a thumb press (543), the distal end (541) includes a coupling portion of the cap (546), The piston rod (540) also includes a flexible protrusion (550) between the thumb press (543) and the main body (544), the protuberance (550) has a cross-sectional width greater than the section width Transversal of the cylinder (520) in the rib (510) and the piston rod (540) further includes a support member (530) that includes an outer edge (539) disposed proximally adjacent to the flexible protuberance (550) and so minus a frangible portion (570) disposed proximally adjacent to the m support member (530) and comprising at least four point connections (572, 573, 574, 575) with a first point connection (573), a second point connection (575), a third point connection ( 572), and a fourth point connection (574) disposed adjacent the edge (539) of the support member (530); The protuberance (550) includes four blades (551, 552, 553, 554) that extend radially outwardly from the piston rod (540) and are arranged equidistant from each other and in which the first point connection (573) and the second point connection (575) is aligned with a first and a second sheet (551, 553), the third point connection (572) and the fourth point connection (574) are aligned with a third and a fourth sheet ( 552, 554), wherein the third point connection (572) and the fourth point connection (574) are disposed adjacent to opposite ends of the outer edge (539) of the support member (530); a plug (560) having a proximal end (589) and a distal end (561), the plug (560) is fixed to the coupling portion of the plug (546) of the piston rod (540) such that when the distal end (561) of the cap (560) is in contact with the distal wall (522) of the cylinder (520), the flexible protuberance (550) is allowed to advance distally beyond the rib (510) in the cylinder ( 520) and block the piston rod (540) in the cylinder (520) to prevent reuse of the syringe assembly, in which the application of a force directed proximally to the plunger (540), after the protuberance (550) has advanced distally beyond the rib (510), causing the frangible portion (570) of the piston rod (540) to break, characterized in that the protuberance (550) bends outwardly from the piston rod (540) towards the proximal end (549) of the piston rod such that each of the sheets so that it has an arcuate shape, so that the flexible protuberance (550) is inhibited from flexing inwardly after the piston rod (540) has been blocked.