WO2008015529A2

WO2008015529A2 - Non reusable syringe with self plunger disengagement system

Info

Publication number: WO2008015529A2
Application number: PCT/IB2007/002170
Authority: WO
Inventors: Prem Chand Gupta; Ravi Kashyap; Rajendra Prashad Triapathi
Original assignee: Director General, Defence Research & Development O
Priority date: 2006-08-02
Filing date: 2007-07-30
Publication date: 2008-02-07
Also published as: WO2008015529A3

Abstract

A single-use disposable syringe is provided which includes a hollow cylindrical body (1) closed at a front end and an opening at a rear end. A first plunger (3) is housed inside the hollow cylindrical body and being located substantially adjacent to the front end. A second plunger (4) is located marginally behind the first plunger and a plunger rod (2) traverses through the second plunger and have a projection formed at about the front end for engaging with the second plunger during a backward/ retraction motion thereof. The plunger rod (2) cooperates with the first plunger (3) during a forward motion and pushes the same toward the front end for the first and the sole time, thereby expelling a fluid contained inside the hollow cylindrical body.

Description

NON REUSABLE SYRINGE WITH SELF PLUNGER DISENGAGEMENT

SYSTEM

FIELD OF INVENTION:

The present invention relates to a Syringe with Self Plunger Disengagement system assembly which can perform just like conventional syringes. The proposed Syringe with Self Plunger Disengagement system is used to injection or drains of fluids in the human body, which deactivates itself after the first and sole use, not allowing therefore, the condemned reutilization of any of its parts (needle included), considering that—in a hypodermic syringe of this type-the needle ,is, molded to body (1).

Proposed design of syringe with self- disengagement plunger system has a specially designed plunger rod with double plungers. The previously proposed concepts, however, proved to be too expensive in production or unreliable in use, since it was possible to manipulate the syringe in such a manner that it might be used again.

It is, thus, an object of the present invention to provide a syringe with self-disengagement plunger system of disposable kind which is inexpensive in production and safe in use.

BACKGROUND ART:

So far, two types of syringes have been manufactured for many years, both of them reusable. The first ones, made of glass and replaceable hypodermic needles, lasts over a century; in recent years a second type emerged from the medical equipment factories, the ones' I lied discarded type set with a plastic body unit and the standard needle, which both should be discarded after the first and sole use. Irrespective of the material used in this medical equipment, the basic components are identical in for and function. The standard syringe includes a cylindrical body (or capsule) fitted snugly onto a hollow needle, and an air-tight piston that features a wider section of its top part to help operator fingers to push it down inserting the desired Liquid into the human body or pulling it back collect the proper material.

The thrown-away type syringes and needles are already sterilized at the factory by state- of-the-art devices, and fee from any and all molesting agents, and packed into sealed plastic envelop s to remain aseptic for years until the moment of use. However, this directive be came useless due to the fact that non-authorized people and drug addicts kept n using them indiscriminately and this led to a spread of diseases and became a public nuisance. The reusing of syringes and their needles are conducive to contamination and in general use among drug addicts and infected patients can and will produce collateral harmful effects in the human body.

The syringe with self- disengagement plunger system eliminates, once for all, any reusing of the assembly so providing the safety and reliability demanded by all. It is an object of the present invention to provide a syringe with self-disengagement plunger system that prevents reuse of the syringe. It is another object of the present invention to provide a syringe with self- disengagement plunger system that is easy-to-use, reliable, and relatively inexpensive.

Various syringes have been invented, designed and developed for single time use only by providing various types of self destructive/self locking mechanisms. Some of these devices with the patent numbers are shown in table: I

Table: I

Most of these designs have problems associated with expense of manufacturing, poor reliability or user acceptability. However, even though some of these designs operate poorly and are costly, they have still been commercialised due to the great need in hospitals or clinics for any type of safety syringe.

SUMMARY OF THE INVENTION:

Syringe with self- disengagement plunger system is designed to provide maximum safety. Normal syringe consists of a plunger rod with the plunger and a cylinder, the proposed design of syringe with self- disengagement plunger system has a specially designed plunger rod with set of plungers. In the suction stroke, the plungers move to the top center and the medicine is sucked into the syringe barrel. During the downward stroke, upper plunger stops at the top center while the lower one can be pushed down ward to inject the medicine in the patient's body. On the completion of down ward stroke the lower plunger become free and cannot be pulled to reuse.

BRIEF DESCRIPTION OF THE DRAWINGS:

1. FIG. 1 shows distinctively the plunger rod (2), Plunger (3) and .plunger (4) at the initial stage, to allow the sliding of the Plunger (3) with plunger (4) to suck the liquid inside the barrel (1).

2. FIG. 2 eminences the plunger (4) condition at the lower end if the stroke thus making the unit (1) completely useless.

DETAILED DESCRIPTION OF THE PRESENT INVENTION:

A single-use disposable syringe comprising a hollow cylindrical body (1) closed at a front end and comprising an opening at a rear end. A first plunger (3) housed inside the hollow cylindrical body and being located substantially adjacent to the front end. A second plunger (4) housed inside the hollow cylindrical body and being located marginally behind the first plunger. A plunger rod (2) traversing through the second plunger (4) and having a projection formed at about a front end for engaging with the second plunger (4) during a backward / retraction motion thereof.

In the single use disposable syringe, the front end of the hollow cylindrical body is formed with a frontal basis (6) for accommodating a hypodermic needle / syringe and the rear end of the hollow cylindrical body is provided with supporting flange (7).

The second plunger (4) is provided with a slot at about its center and the plunger rod (2) snugly traverses through the slot provided in the second plunger (4). The projection formed at about the front end of the plunger rod (2) engages for the first and the sole time with a front surface of the second plunger (4) and thereby imparts motion to the second plunger in the backward direction when the plunger rod is being retracted. The projection formed at about the front end of the plunger rod (2) completely covers the slot formed at about the center of the second plunger (4) and creates pressure gradient between the first and the second plunger when the plunger rod (2) is being retracted, thereby enabling the first plunger to retract and a fluid to enter into the hollow cylindrical body. The plunger rod (2) cooperates with the first plunger (3) during a forward motion and pushes the same toward the front end for the first and the sole time, thereby expelling a fluid contained inside the hollow cylindrical body.

One can infer from the drawings attached that the equipment is composed of a barrel (1) in which the needle is fixed to its frontal basis (6). On the other hand, in the top section of the body (1), with supporting flange (7), specially designed washers are fitted. On the interior of the cylindrical body (1), the plunger (3) is fitted with the specially designed plunger rod. Plunger (4) is placed in front of the plunger (3).

In the initial condition, the assembly is positioned at bottom end. In the upward stroke of the plunger rod (2), Plunger (3) along with plunger (4) moves upward and liquid is sucked in the barrel. In the downward stroke of the plunger rod (2) only plunger (4) moves downward and inject liquid. After reaching the plunger rod (2) with plunger (4) at bottom dead end plunger (4) disconnects and remains in this position to make the complete assembly useless. FIG. 1 shows distinctively the plunger rod (2), Plunger (3) and plunger (4) at the initial stage, to allow the sliding of the Plunger (3) with plunger (4) to suck the liquid inside the barrel (1). In this figure one can also see that at the lower limit of its travel the plunger (4) remains in this position and it is impossible to take it back. FIG. 2 eminences the plunger (4) condition at the lower end if the stroke thus making the unit (1) completely useless.

Claims

We claim:

1. A single-use disposable syringe comprising: a hollow cylindrical housing (1) comprising a front end and a rear end, the said front end being closed by a wall so as to form an interior thereof and the said wall accommodating a means providing a fluid communication path to the interior;

a first plunger (3) housed inside the hollow cylindrical body and being located substantially adjacent to the front end;

a second plunger (4) housed inside the hollow cylindrical body and being located marginally behind the first plunger; and

a plunger rod (2) traversing through the second plunger (4) and having a projection formed at about a front end for engaging with the second plunger (4) during a backward / retraction motion thereof.

2. The single use disposable syringe as claimed in claim 1, wherein the front end of the hollow cylindrical body is formed with a frontal basis (6) for accommodating a hypodermic needle / syringe which is in fluid communication with the interior of said hollow housing.

3. The single use disposable syringe as claimed in claim 1, wherein the rear end of the hollow cylindrical body is provided with supporting flange (7).

4. The single use disposable syringe as claimed in claim 1, wherein the second plunger (4) is provided with an axial slot at about its center and the plunger rod (2) snugly traverses through the slot provided in the second plunger (4).

5. The single use disposable syringe as claimed in claim 1, wherein the projection formed at about the front end of the plunger rod (2) engages for the first and the sole time with a front surface of the second plunger (4) and thereby imparts motion to the second plunger in the backward direction when the plunger rod is being retracted.

6. The single use disposable syringe as claimed in claim 1, wherein the projection formed at about the front end of the plunger rod (2) completely covers the axial slot formed at about the center of the second plunger (4) and creates pressure gradient between the first and the second plunger when the plunger rod (2) is being retracted, thereby enabling the first plunger to retract and a fluid to enter into the hollow cylindrical body.

7. The single use disposable syringe as claimed in claim 1, wherein the plunger rod (2) cooperates with the first plunger (3) during a forward motion and pushes the same toward the front end for the first and the sole time, thereby expelling a fluid contained inside the hollow cylindrical.