SYRINGE WITH MECHANISM TO PREVENT REUSE THEREOF Russian patent published in 2013 - IPC A61M5/50 

FIELD: medicine.

SUBSTANCE: invention refers to medical equipment, namely, refers to a syringe device, and specific versions refers to a mechanism to prevent the syringe reuse. The syringe comprises a cylinder having a cylindrical side wall, an elongated hollow piston rod, a trim at a distal end of the piston rod, and a blocking element. The cylinder has an inner surface forming a chamber for retaining a fluid, an open proximal end and a distal end with a distal wall which provides a passageway for fluid into the chamber. The rod has a proximal end, an open distal end, an inner surface and a distal edge projecting at a distal end. The trim comprises a sealing element with a peripheral surface forming a seal with the inner surface of the cylinder, and a projection extending from the sealing member in the proximal direction and forming a longitudinal recess having a distal portion and accommodating on this distal portion a number of surfaces forming an inclination diverging outwards in the distal direction and a number of supports on the proximal end. The blocking element has a proximal portion having a proximal edge and a distal portion provided with a tooth facing the outside. The blocking element is positioned in the longitudinal recess so that the tooth interacts with the inner surface of the piston rod, and the proximal edge interacts with the projection on the proximal end of the longitudinal groove. The number of the surfaces forming the inclination and the number of supports on the proximal end of the longitudinal recesses interacts so that the distal portion of the blocking member moves along the number of the surfaces forming the inclination with shifting the distal portion of the blocking member to the outside towards the inside of the rod while sliding in the distal direction of the rod and the blocking element. When slides together with the trim inside the chamber at first in the proximal direction and then towards its distal end, the rod makes the tooth projecting beyond the distal projecting edge on the piston rod in the direction of the inner surface of the cylinder to prevent the further movement of the rod relative to the chamber in the proximal direction. In the second version, the syringe comprises a means to block the piston rod in the cylinder when the piston rod is prevented from moving relatively to the cylinder after at least one cycle of the movement of the piston rod in the proximal direction first and then in the distal direction has been carried out, and a means to bias the blocking element in the distal direction relative to the piston rod and to impact on the distal portion of the blocking element inside the hollow piston rod for biasing the distal portion of the blocking element outwardly towards the inner surface of the piston rod, placed on the distal portion of the longitudinal recess. In the third version, the syringe comprises the trim having the projection extending from the sealing element in the proximal direction and forming the longitudinal recess in which its distal end comprises the first and second surfaces forming the inclination and in which the first and second supports are provided. The blocking element is positioned in the longitudinal recess so that the surfaces forming the inclination on the distal end of the longitudinal recess and the supports in the longitudinal recess interact so that the distal portion of the blocking element moves along at least the surface forming the inclination on the distal end, thereby making the distal portion of the blocking element movable outwardly towards the inner surface of the piston rod. The proximal edge of the blocking element keeps it in place. When sliding inside the chamber at first in the proximal direction and then in the distal direction, the piston rod and the trim makes a point extending beyond the distal projecting edge of the piston rod and is deflected towards the inner surface of the cylinder, thereby preventing the further movement of the piston rod relative to the chamber.

EFFECT: invention is the construct simple and inexpensive to manufacture that ensures a specified number of motions of the piston rod before the above automatic mechanism to deactivate the syringe responds.

21 cl, 18 dwg