PISTON FOR USE WITH SYRINGE Russian patent published in 2025 - IPC A61M5/145 A61M5/315 A61M5/36 

FIELD: medicine.

SUBSTANCE: invention relates to a piston intended for use with a syringe. Piston comprises piston body and at least one retaining element. Piston body defines a central longitudinal axis, and has a proximal end, a distal end, and a circumferential side wall connecting the proximal end and the distal end. At least one retaining element is connected to the piston body and extends in the proximal direction from it. At least one retaining member comprises a first end connected to a piston body; a second end proximal to the first end and configured to radially and resiliently deflect relative to the first end; and at least one retainer at the second end. At least one retaining element has an outer surface configured to engage the piston engagement sleeve of the piston engagement mechanism on the plunger of the fluid injection system when the piston is in a fixed state with the plunger. At least one retaining element has an inner surface configured to engage the piston engagement assembly of the piston engagement mechanism when the piston is in a fixed state with the plunger. At least one retainer is made with possibility of fixed engagement of the fixing element on one of the piston engagement sleeve and the piston engagement assembly when the piston is in a fixed state with the plunger to prevent axial movement of the piston relative to the plunger. At least one retainer has a first rounded or inclined proximal surface at the proximal end of at least one retainer for flexible engagement of the distal end of the retainer on one of the engagement sleeve of the piston and a piston engagement assembly during engagement of the piston with the plunger, and a second rounded or inclined distal surface at the distal end of the at least one retainer for flexible engagement of the proximal end of the retainer on one of the piston engagement sleeve and piston engagement assembly during piston disengagement from plunger. In the unlocked state of the piston engagement mechanism, the first rounded proximal surface and the second rounded distal surface of at least one retainer are configured to radially deflect the second end of at least one retaining element during axial movement of the plunger relative to the piston as a result of flexible interaction of at least one retainer with a fixing element on one of the engagement sleeve of the piston and the engagement assembly of the piston.

EFFECT: invention provides simpler and easier engagement of the syringe plunger with the plunger of the injector for the liquid introduction and disengagement of the syringe plunger with it, reduces or eliminates the need for the operator by means of rotation to align the syringe with the injector for liquid introduction before engagement of the syringe piston with the plunger of the injector for liquid introduction.

13 cl, 35 dwg