SYRINGE WITH DEACTIVATING MECHANISM Russian patent published in 2012 - IPC A61M5/50 A61M5/315 

FIELD: medicine.

SUBSTANCE: invention refers to medical equipment, namely syringe devices and particularly syringes with an automatic disabling mechanism. A syringe with a passive deactivating system comprises a cylinder, an elongated piston rod, a cuff, a means for free axial motion restrict of the cuff towards the piston rod at a limited direction and for application of proximal and distal forces to the cuff by means of the piston rod, a blocking element and controls for free axial motion of the cuff towards the piston rod. A cylinder comprises a side wall with an internal surface forming a chamber for fluid medium confinement, an open proximal end and a distal end containing a distal wall with a passage for communication with the chamber. The elongated piton rod has a proximal end and an open distal end with an internal surface forming a cavity, at least one support on the internal surface on the distal end of the piston rod, and a second cavity at the proximal end of said cavity and having distal and proximal ends, a contact surface and at least one surface discontinuity in the second cavity. The cuff comprises a sealing element with a peripheral surface forming a tight seal with the internal surface of the cylinder, a rod extending in a proximal direction from the sealing element, with a proximal end and a distal end, at least two supports on this rod, a second rod extending along the axis from the proximal end of the rod, having the proximal end, the distal end, an external surface and at least one external surface discontinuity and arranged at least partially in the second cavity. The means for free axial motion restrict of the cuff comprises at least one motion limiting surface discontinuity on the second rod arranged for coupling with at least one motion limiting discontinuity in the second cavity. At least one motion limiting discontinuity on the second rod involves an outward-directed projection. At least one motion limiting discontinuity in the second cavity contains an inward-directed projection with a free end. The blocking element comprises a central section of the body with a passage therethrough, at least one console leg extending in the distal direction outwards from said section of the body, and at least one finger extending in the proximal direction inwards said passage. At least one leg has a pointed free end directed outwards for coupling with the internal surface of the cylinder. The blocking element is placed so that its pointed free end contacts with the internal surface of the piston rod in the proximal direction of at least one support in the proximal rod. The rod is arranged in the passage of the blocking element. At least one finger contacts with the most proximal one of the two supports of the rod so that applying proximal force to the piston rod with the cylinder held induces the proximal motion of the piston rod with respect to the cuff while the free end of the console leg moves in the distal direction along the internal surface of said cavity of the piston rod to said at least one support in this cavity. The means for motion restrict makes the cuff moving together with the piston in the proximal direction at a selected distance, while applying distal force once more to the piston rod for fluid pumping from the chamber through said passage makes the piston rod moving in the distal direction together with the blocking element due to coupling with said at least two supports of the rod while the means for motion restrict does not make the cuff moving in the distal direction with the piston rod for fluid pumping from the chamber; thereafter applying proximal force to the piston rod with the free end of the console leg moving in the distal direction along the internal surface of said cavity behind the distal end of the piston rod so that at least one console leg couples with the internal surface of the cylinder thereby helping to prevent the proximal motion of the cuff and disabling the syringe. The controls of free axial motion of the cuff involve a free end of the inward-directed projection having a friction contact with the external surface of the second rod increasing force required to move the cuff with respect to the piston rod, a proximal hollow in the external surface of the second rod adjoining the outward-directed projection of the second rod, and a distal hollow in the external surface of the second rod gapped from the proximal hollow. The distance of the proximal and distal hollows match with free axial motion of the cuff with respect to the piston rod, with the free end of the inward-directed projection in the distal hollow when cuff sealing is closest to the piston rod, and in the proximal hollow when cuff sealing is furthest from the piston rod. Force applied to the piston rod for moving the free and inward-directed projection from any of said hollows is more than force required for moving said free end along the external surface of the second rod between the hollows thereby holding the cuff in the most distal and most proximal positions unless the greatest force is applied.

EFFECT: invention prevents accidental and unintentional motion of the piston rod with respect to the cuff.

11 cl, 26 dwg