RU2080881C1 - Expendable syringe - Google Patents

Abstract

FIELD: medical engineering, expendable syringes. SUBSTANCE: syringe comprises casing with needle holder which has hollow piston, rod, and coupling device for joining piston to rod. Coupling device includes longitudinal cut 10 made on rod and matched with recess 11 formed on internal side surface, lock 9 movable into recess 11, projection 12, and shoulder 13 capable of cooperating with each other. Novelty of syringe resides in fact that tabs 8 formed by longitudinal cut in rod are made resilient, projection 12 is formed on external side surface of tabs, while shoulder 13 is formed on internal side surface of piston. EFFECT: improved reliability.

Description

 The invention relates to medical equipment, namely to syringes used for only one injection.

 Known syringe containing a housing, inside of which there is a piston with a rod and a device for blocking the stroke of the piston.

 The disadvantage of the syringe is the ability to dismantle or disable the device for blocking the stroke of the piston, as a result of which the syringe can be reused.

 A syringe is also known, which contains a housing, a piston with a rod and a device for blocking the stroke of the piston.

 Such a syringe can be used repeatedly if during the injection the piston is not brought to the extreme position in which it is blocked.

 The closest in technical essence and the achieved result to this invention is a disposable syringe containing a housing with a needle holder, inside of which there is a piston with a cavity, a rod and a device for connecting the piston to the rod, including a longitudinal section made on the rod with a recess on the inner side surface, a stopper having the inability to move into the recess and made with the possibility of contacting a protrusion and a shoulder.

 In the indicated syringe, the petals formed by the transverse section are not elastic, as a result of which, when the rod moves towards the needle holder, the force transmitted by the rod to the stopper may not be sufficient to move the stopper into the recess and the shoulder will not come out of engagement with the protrusion. As a consequence, the likelihood of reuse of the syringe increases.

 The aim of the invention is to reduce the likelihood of reuse of the syringe by increasing the reliability of the disconnection of the piston with the rod by reducing the force applied to the rod.

 This goal is achieved by the fact that in a disposable syringe containing a housing with a needle holder, inside of which a piston with a cavity is located, a rod and a device for connecting the piston to the rod, including a longitudinal section made on the rod with a recess on the inner side surface, a stopper that can be moved into the recess, and made with the possibility of contacting each other, the protrusion and the flange formed by a longitudinal section of the stem petals are made elastic, the protrusion is made on the outer lateral erhnosti lobes and the collar on the inner side surface of the piston.

 Figure 1 shows a syringe in its original state; figure 2 also after injection; figure 3 section aa of figure 1; figure 4 section BB of figure 1.

 The syringe consists of a housing 1 with a needle holder 2 and a locking pin 3, a cover 4, a rod 5, a piston 6 with a cavity 7 and a device for connecting the piston to a rod containing elastic petals 8, between which a stopper 9 is located. The elastic petals 8 are formed on the rod a longitudinal section 10 with a recess 11 on the inner side surface and equipped with a protrusion 12 on the outer surface, engaging with a shoulder 13 made on the inner side surface of the piston. Petals 8 tend to shrink toward the axis of the syringe.

 The syringe works as follows.

 In the initial state, the piston 6 is in the extreme (lower) position from the needle holder 2. The movement of the rod 5 towards the needle holder 2 is limited by the locking pin 3.

 During the filling period of the syringe, the piston 6 moves the rod 5 away from the needle holder 2. The connection of the piston 7 with the rod 5 during this movement is provided due to the engagement of the tab 12 of the petals with the shoulder 13 of the piston.

 Then, the locking pin is removed by tearing or breaking it.

 During the return movement of the rod 5 (air exhaust and injection), the petals 8 of the sleeve move first in the cavity 7 of the piston, and then together with the piston 6 towards the needle holder 2. In this case, the stop 9, abutting the end surface of the piston 6, enters the recess 11, letting the petals 8 shrink among themselves.

 After the injection, the petals 8 freely leave the cavity 7 of the piston. This makes reuse of the syringe impossible.

Claims (1)

 A disposable syringe containing a housing with a needle holder, inside of which a piston with a cavity is placed, a rod and a device for connecting the piston to the rod, made in the form of a sleeve with elastic petals and a stopper, characterized in that a flange is made on the inner side surface of the piston, the sleeve is fixed to the rod, its petals are made with internal recesses and external protrusions located in the piston cavity with the possibility of contacting with the shoulder, and the stopper is located between the petals of the sleeve with the possibility of its about moving into the internal recesses of the petals.

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